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In addition, the stormwater impounded in Lake Calavera is utilized in this alternative by
providing a stormwater treatment facility that would treat this water during the peak summer
months (July through September) to provide additional supply. Per the CMWD’s 2006 Lake
Calavera Annual Management and Daily Operations Plan (CMWD, 2006), the reservoir has
a 25-foot operational storage range between 189 ft-msl and 214 ft-msl. This operational
storage range provides a total storage capacity of 480 MG. The report also states that the
annual dry year runoff into the reservoir varies between 32 and 97 MG. Based on this
information, the proposed stormwater treatment plant is sized to treat 90 MG in 90 days,
which equates to 1 mgd. The location of this proposed facility is shown on Figure 4.4.
Based on similar treatment of surface water sources, the proposed stormwater treatment
plant (SWTP) is outlined based on a conventional treatment process involving a rapid mix
chamber, coagulation in a flocculation basin, sedimentation, filtration, and chlorine addition.
This process assumes that the water in Lake Calavera has characteristics typical of a
surface water supply. During planning and design of a potential plant, the processes used
could change depending on the measured water quality of Lake Calavera.
To connect this new SWTP with CMWD’s recycled water distribution system, 4,000 feet of
8-inch diameter pipeline along between the Calavera Reservoir and “C” Tank needs to be
constructed as shown on Figure 4.4. This pipeline along with a new booster pumping
station would provide a direct connection with Zone 384 and pump into the C-tank feedline.
Connection to Zone 580 is not an option due to the limited maximum month demand
(<0.4 mgd) of this pressure zone.
The Carlsbad WRF would be expanded by 5.0 mgd to provide the balance of the required
supply. It is assumed that the proposed expansion of the Carlsbad WRF from 4.0 mgd to
9.0 mgd can be accommodated at the current site and that this expansion will be limited to
the tertiary treatment processes and disinfection capacity. As the plant already has
approximately 14.4 mgd of effluent pumping capacity, no additional pumping capacity is
anticipated. However, if the pump station at Carlsbad WRF is used to meet PHD, additional
pumping capacity will be needed.
To determine the capital construction cost of this alternative, the following key components
were included:
• 1-mgd stormwater treatment plant (SWTP) with microfiltration and UV disinfection.
• 1-mgd discharge pumping station at the new SWTP to serve Zone 384.
• 4,000 feet of 8-inch diameter pipeline between the Calavera Reservoir and “C” Tank.
• 5-mgd tertiary filter capacity expansion at Carlsbad WRF.
• 5-mgd chlorine contact basin capacity expansion at Carlsbad WRF.
• No expansion of effluent pumping capacity at Carlsbad WRF.
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• 1,500 feet of 8-inch diameter pipeline and 75 hp pump station sized for 0.75 mgd to
convey flow from Gafner WRP to distribution system (future Expansion Segment 8 in
El Camino Real).
The estimated capital cost of this alternative is $18.9 million. A detailed breakdown of this
estimate is included in Appendix B. Assuming an annual demand of 4,098 afy made
possible by this expansion, the unit supply cost of this alternative is estimated at $335/af.
4.4.6 Alternative 6 - Utilize Shadowridge WRP
This alternative also expands CMWD’s current supply mix by securing water from a new
supply source, while continuing to use recycled water from the Carlsbad WRF, Meadowlark
WRF, and the Gafner WRP. Meadowlark WRF remains at current capacity in this
alternative providing 3.0 mgd. Gafner WRP is connected to the distribution system, allowing
full utilization of the 0.75 mgd allocation. Seasonal storage is used for 0.2 mgd of MMD
supply.
In addition, this alternative would utilize recycled water from a reactivated Shadowridge
Water Reclamation Plant (SRWP), the location of which is shown on Figure 4.4. The VID is
currently evaluating the necessary improvements required for reactivating the plant and has
discussed the potential alternatives with CMWD. The two potential alternatives evaluated
by VID’s study that would provide recycled water to CMWD’s system are shown in
Table 4.8 (a third alternative supplied recycled water only to VID’s service area).
Table 4.8 Alternatives for Expansion of Shadowridge WRP
Recycled Water Master Plan
Carlsbad Municipal Water District
Shadowridge WRP
Alternative(1)
Plant Capacity
(mgd)
Supply to CMWD(2)
(mgd)
Unit Cost(3) w/ O&M
($/acre-foot)
Unit Cost w/o O&M
($/acre-foot)
Alternative 2 1.0 0.7 $1,520 $714
Alternative 3 2.0 1.7 $1,070 $567
Notes:
(1) Alternative 1 does not consider service to CMWD’s recycled water system.
(2) These flows are average annual supply. See discussion below for further information.
(3) Source: Draft Summary of Shadowridge WRF Upgrade and Renovation Alternatives. VID’s reactivation
study assumed Carlsbad would purchase all excess water. See discussion below for further information.
As seen in Table 4.8, the anticipated average annual supply to CMWD would be 0.7 mgd
and 1.7 mgd under Alternatives 2 and 3, respectively. It is important to note that under each
of the alternatives, the calculations of unit cost assume that CMWD will purchase all
recycled water not used by the Shadowridge Golf Course.
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As shown in Table 4.8, VID’s study also included operations and maintenance costs. Since
the comparison presented in this section for each supply alternative presents capital costs,
the operations and maintenance costs are deducted in Table 4.8 for relative comparison
purposes. Operations and maintenance costs by supply source will be included in
Section 4.4.8.
Since the demand of the Shadowridge Golf Course will peak in the summer and be very low
in the winter months, the availability of this supply will be opposite from CMWD’s seasonal
supply requirements, as shown in Table 4.9.
Table 4.9 Seasonal Supply Related to Shadowridge WRP Recycled Water Master Plan
Carlsbad Municipal Water District
Average Day
(mgd)
Maximum Month(1)
(mgd)
Minimum Month(2)
(mgd)
CMWD’s Existing Demand 3.6 6.1 0.7
Build Out Demand
(with Neighboring Agencies)
8.1 13.5 1.6
Supply with Alternative 2 0.7 0.3 1.0
Supply with Alternative 3 1.7 1.3 2.0
Notes:
(1) Discussions with CMWD staff indicated that demands of the Shadowridge Golf Course during Maximum Month demand conditions are anticipated to be 0.7 mgd.
(2) Source: Draft Summary of Shadowridge WRF Upgrade and Renovation Alternatives. VID’s reactivation study assumed Carlsbad would purchase all excess water. See discussion below for further information. Discussions with CMWD staff indicated that demands of the Shadowridge Golf Course during Minimum Month demand conditions are anticipated to be zero.
As shown in Table 4.9, even under the build-out conditions, the minimum month demand of
1.6 mgd would still be less than the 2.0 mgd supply during minimum months from
Shadowridge WRP (Alternative 3). As the unit costs shown in Table 4.8 necessitate that
CMWD purchase all excess water generated by Shadowridge WRP, CMWD would not be
able to take supply from Meadowlark WRF while paying for its full allotment of 2 mgd.
Based on this, Shadowridge WRP Alternative 3 is not financially feasible and Alternative 2
was used for this study. It should be noted that CMWD’s build-out minimum month demand
would still under utilize supply from Meadowlark WRF under this alternative.
Carlsbad WRF would be expanded by 5.75 mgd to provide the balance of the required
supply. It is assumed that the proposed expansion of the Carlsbad WRF from 4 mgd to
9.75 mgd can be accommodated at the current site and that this expansion will be limited to
the tertiary treatment processes, disinfection, and effluent pumping capacity. As the plant
already has approximately 14.4 mgd of effluent pumping capacity, additional pumping
capacity is not anticipated. However, if the pump station at Carlsbad WRF is used to meet
PHD, additional pumping capacity will be needed.
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The unit costs shown in Table 4.8 do not include conveyance from Shadowridge WRP to
CMWD’s distribution system. As a part of discussions with VID, several alternatives for
delivery of recycled water from the Shadowridge WRP to CMWD’s system were suggested.
The two most feasible of these delivery methods were:
• Conveyance by gravity through Shadowridge WRP’s existing failsafe pipeline to
Carlsbad WRF, where it would need to be pumped back up to Zone 550.
• Construction of a pump station at Shadowridge WRP to supply the recycled water to
Zone 660. The capacity to transfer the additional supply from Zone 660 to Zone 550
would need to be developed within the infrastructure of CMWD’s distribution system.
Table 4.10 Preliminary Costs for Delivery from Shadowridge WRP
Recycled Water Master Plan
Carlsbad Municipal Water District
Cost Component
Alternative 1: Gravity Flow to El Camino Real and
Palomar Airport Rd.
Alternative 2: Pressurized Flow to Zone 660 at
Melrose Dr. and Faraday St.
Pump Station
Size (hp) 70 60
Cost $660,000 $550,000
Transmission Main $190,000 $750,000
PRS - $50,000
Total $850,000 $1,350,000
Based on the preliminary cost estimate shown in Table 4.10, it is estimated that
conveyance through the gravity pipeline would be the most cost-effective solution and will
be used for comparison costs for this supply alternative. Alternative 2 is the more costly
option due to the additional transmission main improvements required to convey flow
through Zone 660 and a new pump station that would be needed at Shadowridge WRP.
To determine the capital construction cost of this alternative, the estimated capital costs
from VID’s reactivation study were combined with the conveyance and expansion costs for
Carlsbad WRF. The following key components were included:
• 1-mgd reactivation of Shadowridge WRP (cost from VID study).
• 1-mgd pump station to Zone 550 at the delivery point from Shadowridge WRP (near
El Camino Real and Palomar Airport Road).
• 750 feet of 12-inch diameter pipeline between the failsafe pipeline, pump station, and
distribution system.
• 5.75-mgd tertiary filter capacity expansion at Carlsbad WRF.
• 5.75-mgd chlorine contact basin capacity expansion at Carlsbad WRF.
• No additional effluent pumping capacity at Carlsbad WRF.
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• 1,500 feet of 8-inch diameter pipeline and 75 hp pump station sized for 0.75 mgd to
convey flow from Gafner WRP to distribution system (future Expansion Segment 8 in
El Camino Real).
The estimated capital cost of this alternative is $22.8 million. A detailed breakdown of this
estimate is included in Appendix B. Assuming an annual demand of 4,098 afy made
possible by this expansion, the unit supply cost of this alternative is estimated at $404/af.
4.4.7 Supply Evaluation Summary
A summary of the supply alternatives evaluation is shown in Table 4.11 and graphically
presented on Figure 4.7.
Table 4.11 Supply Alternatives Cost Comparison Recycled Water Master Plan
Carlsbad Municipal Water District
Supply Source Facility
Treatment Flow (mgd) Alternative 1 Maximize CWRF Alternative 2 Maximize MWRF Alternative 3 Maximize GWRP Alternative 4 Abandon GWRP Alternative 5 Maximize CWRF and Lake Calavera Alternative 6 Utilize Shadowridge WRP Carlsbad WRF 10.25 9.75 7.00 11.00 9.00 9.75
Meadowlark WRF 3.00 3.50 3.00 3.00 3.00 3.00
Gafner WRP(4) 0.75 0.75 4.00 - 0.75 0.75
Calavera Reservoir SWTF - - - - 1.00 -
Seasonal Storage - - - - 0.25 0.20
Shadowridge WRP - - - - - 0.30
Total Supply (mgd) 14.00 14.00 14.00 14.00 14.00(5) 14.00
Capital Cost ($ million) $10.8 $16.9 $73.6 $10.2 $18.9 $22.8
Unit Cost(1) ($/acre-foot) $191 $300 $1,305 $181 $335 $404
Notes:
WRF = Water Reclamation Facility; WRP = Water Reclamation Plant; SWTF = Stormwater Treatment Facility
(1) Unit Cost based on average supply capacity of 9,106 afy (an increase of 4,098 afy from the current supply of 5,008 afy).
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$191
$300
$1,305
$181
$335 $404
$0
$200
$400
$600
$800
$1,000
$1,200
$1,400
$1,600
0
2
4
6
8
10
12
14
16
Alt. 1 Alt. 2 Alt. 3 Alt. 4 Alt. 5 Alt. 6 Unit Supply Cost ($/af)Supply Capacity (mgd)CWRF GWRP MWRF
SWTP Seasonal Storage SWRP
Unit Cost ($/af)
Figure 4.7 Supply Alternatives Comparison
As shown on Figure 4.7, the majority of the recycled water supply capacity is produced at
the Carlsbad WRF in all alternatives, ranging from 7 to 11 mgd of the total 14-mgd supply
capacity. This figure clearly shows that the variations between alternatives are determined
by the supply mix of the remaining 3 to 7 mgd of the total 14-mgd supply capacity.
In addition to the supply mix of each alternative, Figure 4.7 also shows the estimated unit
capital supply cost in dollars per acre-foot. These unit supply cost are based on the project
components discussed in Sections 4.4.1 through 4.4.6, which are presented in more detail
in Appendix B. The total capital costs of each alternative are depreciated over a 30-year
period and amortized with a 6 percent interest rate. As shown in Figure 4.7, the estimated
unit supply costs range from $181/af to $1,305/af. It should be noted that this cost does not
include the cost of secondary treatment at EWPCF, land acquisition costs, existing costs of
recycled water, nor operations and maintenance cost of treatment and distribution system
facilities.
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Based on the capital unit supply cost comparison, it can be concluded that Alternative 4 is
the most cost-effective alternative and that Alternative 1 is a close second-best alternative.
However, it should be noted that this evaluation does not include O&M cost, which is
discussed in the next section. A final recommendation is therefore made at the end of this
chapter. Some additional benefits of Alternatives 1 and 4 are:
• Carlsbad WRF was originally designed to be expanded to 16 mgd and the facility
layout and distribution system are designed with this ultimate capacity in mind.
Carlsbad WRF has therefore sufficient land available for expansion.
• Carlsbad WRF has the necessary treatment processes and configuration to remove
TDS and manganese to acceptable levels through the microfiltration and reverse
osmosis process that treats 20 percent of the total flow. Note that it is assumed that
expansion of the microfiltration and reverse osmosis process is not necessary and the
long-term efficiency of use of the microfiltration and reverse osmosis process to treat
manganese should be evaluated during design of the expansion.
• Carlsbad WRF is owned and operated by CMWD and therefore does not require any
inter-agency agreements. CMWD will have more control over the expansion,
operation, and maintenance of this facility compared to the Gafner WRP or
Meadowlark WRF, which are owned and operated by other agencies.
Alternative 2 maximizes the use of the Meadowlark WRF at 3.5 mgd. This alternative would
require CMWD to obtain all the supply rights from this plant from OMWD. This would only
be feasible if OMWD obtained more recycled water from CMWD’s distribution system,
which would require an expansion of the Carlsbad WRF similar in size to Alternative 1.
OMWD could purchase recycled water from CMWD through a new connection pipeline
along El Camino Real that would connect CMWD’s Zone 384 with OMWD’s recycled water
system near La Costa Golf Course as OMWD already has infrastructure in place south of
this golf course. Moreover, Alternative 2 would also require OMWD to construct one or
more booster pump stations to deliver water from the new connection to their higher
pressure zones, which are currently fed by gravity from Mahr Reservoir and the
Meadowlark WRF. As this supply strategy is not attractive for operational, design, and
reliability considerations, it is not likely that OMWD would exchange supply from
Meadowlark WRF with supply from Carlsbad WRF. Due to the uncertainty of OMWD’s
expansion plans and schedule, it is recommended that CMWD not plan for additional
supplies from the Meadowlark WRF.
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Alternative 3 is not recommended as it is the most expensive alternative in $/af. The
relatively high cost is attributed to the required MF/RO treatment required for the plant
expansion at the Gafner WRP, due to Gafner WRP’s limited onsite space. Another factor
impacting the cost of this alternative is the water quality constraints as Gafner WRP would
need to provide water meeting the TDS requirements of the basin plan.
Alternative 5 is not recommended as the SWTP and pipeline make this alternative relatively
costly as it would only operate potentially 7 months per year during a wet year. In addition,
treated stormwater may pose water quality concerns and variable lake levels may cause
environmental concerns and could require mitigation measures. With sufficient secondary
effluent and potential treatment capacity available at the Carlsbad WRF, the use of runoff
water in Lake Calavera as a recycled water supply source is not cost-effective at this time.
Alternative 6 is not recommended since it is more costly than Alternatives 1, 2, 4, and 5, but
does not provide the benefit of maintaining facilities under CMWD’s own control. CMWD is
able to take advantage of economies of scale in expanding the Carlsbad WRF more
efficiently than reactivating the Shadowridge WRP, while not being concerned with
interagency agreements and coordination to ensure that the Shadowridge WRP operates at
capacity to meet a contracted 1-mgd delivery of recycled water. This alternative would also
underutilize the Meadowlark WRF in the near-term, making the overall supply cost even
higher.
4.4.8 Unit Cost Comparison by Supply Source
In addition to the comparison of supply alternatives, the unit supply cost for each supply
source was calculated to take into account the purchase agreements for recycled water
from neighboring agencies as well as the operations and maintenance costs paid by
CMWD. The unit costs for each supply source are shown in Table 4.12. Note that the flows
shown are based on full utilization of each source, and thus are not necessarily comparable
to the unit costs shown in the previous section.
As shown in Table 4.12, Carlsbad WRF is CMWD’s lowest cost supply source when
considered on a unit cost basis. Meadowlark WRF is CMWD’s second lowest cost supply
source. Note that Gafner WRP and Meadowlark WRF both have minimum purchase
agreements, below which unit costs of supply will effectively increase. It is assumed that
Shadowridge WRP would have a similar agreement.
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Table 4.12 Supply Source Unit Cost Comparison
Recycled Water Master Plan Carlsbad Municipal Water District
Supply Source Facility
Unit Cost ($/af)
Based On Capital O&M Total
Carlsbad WRF(1) 10.25 mgd $259 $249(2) $508
Gafner WRP(3) 0.6 mgd $988
Meadowlark WRF(4) 2.67 mgd $80 $481 $561
Shadowridge WRP(5) 0.7 mgd $715 $805 $1,520
Calavera SWTF(6) 1 mgd $610 $448 $1,058
Notes: (1) Based on cost estimate for expanding Carlsbad WRF from 4 mgd to 10.25 mgd (Alternative 1) and existing capital recovery; incorporates effluent pumping cost to Zone 384. The unit cost of 259 $/af includes 68 $/af for the existing capital recovery associated with 4 mgd of capacity and 191 $/af for future capital recovery associated with the 6.25 mgd expansion. The O&M unit cost of $249 includes $78
associated with fixed costs and $171 associated with non-fixed costs. Note that this supply comparison assumes 5,725 afy utilization of the treatment plant capacity. Actual utilization may be substantially less due to peaking and the timeline of connecting customers.
(2) Derived from Encina JPA FY08/09 costs listed in Encina JPA FY10/11 budget and supply volume from CMWD sales report to MWD for FY08/09. It was assumed that personnel and internal service fund costs would be similar to current costs. Non-personnel expenses, such as energy, chemicals, and repairs were
assumed to scale based on utilization of Carlsbad WRF. (3) Based on current 2010 rate set at 99% of CMWD potable water rate and minimum purchase of 395 afy (0.35 mgd) of recycled water. Based on wholesale rate; no consideration of capital and O&M costs are
included. Note that unit cost would also be applicable to supply of 0.75 mgd if capital costs for connection are excluded. (4) Based on capital recovery and O&M percentages listed in August 20, 2003 agreement with VWD and
VWD operating budget for FY10/11. Assumed purchase of 2,989 afy. (5) Costs based on preliminary cost estimate of PBS&J study on reactivation of Shadowridge WRP. Assumed minimum purchase of 728 afy.
(6) O&M cost are based on typical water treatment O&M costs from AWWA/WEF QualServe performance measurement program ($1,373 per MG processed). Calavera supply is 276 afy or 90 MG.
4.4.9 Potable Water Supplement Alternative
CMWD’s existing facilities have sufficient capacity to accommodate existing and future
customers through build out conditions for a portion of the year. However, the supply
capacity is insufficient to meet the peak demands during the summer. The supply
Alternatives 1 through 6 presented previously all provided combinations of treatment plant
expansions to meet the build out recycled water demand with tertiary treated water.
However, another alternative is to not build any new facilities and use potable water to
supplement the recycled water supply during peak months. This option is referred to as the
Potable Water Supplement Alternative and is compared with Alternative 4 to determine if it
is cost-effective for CMWD should expand its treatment facilities.
This comparison is based on the incremental treatment capacity needed to serve a build
out demand of 9,106 afy. As the existing treatment facilities can serve about 5,008 afy and
meet the seasonal demand needs, the incremental treatment capacity or potable water
supplement capacity is based on an annual demand of 4,098 afy.
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To evaluate the cost effectiveness of using potable supplement water for seasonal peaking,
the annual amount of supply in excess of the existing supply capacity was calculated based
on a build-out demand of 9,106 afy. Based on the historical seasonal demand variation
shown in purple on Figure 4.8, the required amount of potable supplement water was
estimated at 2,271 afy.
As it is anticipated that the build out demand of 9,106 afy will be reached around year 2030,
the need and cost of potable supplement water will increase over time. To estimate the cost
of this alternative, the potable water rate projected by SDCWA for year 2018 was used.
This year represents the approximate time that about half of the remaining customers are
connected, a few years before completion of Phase III. This is also SDCWA’s furthest year
out for which a rate projection is available. SDCWA estimates that their wholesale rate will
reach $1,757 per afy by 2018. Based on this wholesale rate and an annual potable water
supplement demand of 2,271 afy, the annual cost of this alternative is estimated at nearly
$4 million. This equates to a unit supply cost of $974/af using an annual demand of
4,098 afy.
2.0 2.0 2.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 2.0
0.9 0.8 1.2
3.9 4.0 4.0 4.0 4.0 4.0 4.0 4.0
2.4
0.8
0.8 0.8 0.8 0.8
3.4 5.1 5.7
4.2
3.9
0
200
400
600
800
1,000
1,200
0
2
4
6
8
10
12
14
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Monthly Demand (af)Average Daily Demand per Month (mgd)Meadowlark WRF Carlsbad WRF
Gafner WRP Potable Supplement
CMWD Build-out Demand (afy)
Figure 4.8 Required Potable Supplement as Seasonal Supply
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Table 4.13 presents a comparison of using potable supplement water with the capital and
O&M cost associated with serving the incremental demand of 4,098 afy through an
expansion of Carlsbad WRF as recommended in Alternative 4. The cost of Alternative 4
includes $181/af for capital expansion as shown in Table 4.11. In addition, the demand
weighted O&M cost for operating the treatment plant expansion is about $377/af. The
combined cost of Alternative 4 is therefore estimated at $568/af.
Table 4.13 Comparison of Potable Water Supplement with Alternative 1
Recycled Water Master Plan Carlsbad Municipal Water District
Cost Component
Potable Water
Supplement
Alternative(1)
Alternative 4
6-mgd Carlsbad WRF
Expansion(2)
Capital Cost ($) - $10,800,000
Annual Cost ($/year) $3,990,147 $785,000
Unit Cost ($/af) $974(3) $568(4)
Notes: (1) Based on annual demand of 9,106 afy for build out. Assumed to have negligible capital costs (potentially,
additional potable supplement water through an air gap). (2) Based on annual demand of 9,106 afy for build-out of CMWD service area and neighboring agencies. (3) Unit cost only reflects the cost of 4,098 afy of wholesale treated water and does not include the unit cost for
the other supply sources needed to meet the annual demand of 9,106 afy. (4) Based on $191 per af for capital recovery of the Carlsbad WRF expansion; $78 per af for fixed O&M costs at Carlsbad WRF; $171 per af for non-fixed costs at Carlsbad WRF; $377 per af for O&M and $481 per af
for Meadowlark WRF
As shown in Table 4.13, Alternative 4 is much more cost-effective than purchasing potable
supplement water. This comparison does not include the cost of supplying up to 5,008 afy
with the existing facilities, as those costs will be the same for both alternatives. This
analysis also does not consider the loss of MWDSC’s LRP reimbursement, energy cost due
to elevation difference between the potable water connection and Carlsbad WRF.
It should be noted that the use of potable supplement water may be practical and required
on an incidental basis, but that this is not a valid long-term supply strategy, especially when
potable water rates continue to increase over time.
4.4.10 Recommended Supply Alternative
The recommended alternative for expanding recycled water supply is Alternative 4, which
calls for a 7-mgd treatment plant expansion at the Carlsbad WRF. Alternatively, CMWD
may want to consider Alternative 1, which calls for a 6.25-mgd treatment plant expansion at
Carlsbad WRF.
The expansion of Carlsbad WRF will need to be implemented based on the phasing of
demands and expansion segments discussed in Chapter 9. Phasing of each increment of
expansion of the treatment plant and the associated supply strategy will be discussed in
more detail in Chapter 9.
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Chapter 5
RECYCLED WATER REGULATIONS
The production, discharge, distribution, and use of recycled water are subject to federal,
state, and local regulations. The primary objective of these regulations is to protect public
health. This chapter starts with a discussion of the roles and responsibilities of the agencies
involved in the use of recycled water. Subsequently, the existing regulations on federal,
state, regional, and local level are described. This chapter is concluded with a discussion
on future regulations and the impact to the Carlsbad Municipal Water District (CMWD).
5.1 OVERVIEW OF REGULATING AGENCIES
The 1996 Memorandum of Agreement (MOA) between the California Department of Public
Health (CDPH), the State Water Resources Control Board (SWRCB), and the Regional
Water Quality Control Boards (RWQCBs) allocate the primary areas of responsibility and
authority between these agencies on the use of recycled water. The CDPH is the primary
state agency responsible for public health, whereas the SWRCB and the RWQCBs are the
primary state agencies charged with protection, coordination, and control of surface and
groundwater quality. These agencies work together to develop plant discharge or master
reclamation permits for recycled water projects. Generally, the CDPH interprets the laws
dictated by the California Code of Regulations (CCR) applicable to reclamation and makes
recommendations on individual projects to the RWQCB. The RWQCB issues the final
permit for water reclamation projects. In addition, in the County of San Diego, the CDPH
has delegated the review of proposed recycled water use areas, use site distribution plans,
complete cross connection control shutdown testing, and use site inspections to the
County’s Department of Environmental Health (DEH). The roles of the agencies involved in
the management of recycled water are summarized in Table 5.1.
5.2 FEDERAL REGULATIONS
While wastewater discharges are governed by both federal and state requirements,
currently there are no federal regulations that directly govern water recycling practices in
the United States.
Federal regulations relevant to the discharge of recycled water, wastewater, and any other
liquid wastes to “navigable waters” are contained in the 1972 amendments to the federal
Water Pollution Control Act of 1956, commonly known as the federal Clean Water Act
(Public Law 92-500).
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Table 5.1 Roles of Agencies Involved in Recycled Water Use
Recycled Water Master Plan Update Carlsbad Municipal Water District
Responsibility CDPH
RWQCB
City of
Carlsbad
RW
Customer DEH
Treatment Facility
Review treatment plant design
criteria
x X
Title 22 Engineering Report x X
Treatment Plan Inspections x X
Discharge Permits x X
Enforcement actions for
non-compliance
x X
Distribution System
Review for standards
compliance
x X
Recycled water permits X
Annual Title 17 Inspections X
Backflow prevention device
testing
X x
Review cross-connection
programs
x
Customer Site Areas
Develop standards for use areas X x
Review/approve supplier rules
and regulations
x X
On-site inspection x x X X
Cross-connection inspection X X X
Cross-connection testing X X X
Monitoring on-site use X X x
Enforcement actions for
non-compliance
x X x
Notes: Source: California-Nevada Section American Water Works Association (AWWA, 1997) X = Entity with primary responsibility
x = Entity with secondary responsibility
Federal requirements relevant to the use of recycled water for groundwater recharge are
contained in the 1986 amendments of the Safe Drinking Water Act of 1974 (Public Law
93-523). The Safe Drinking Water Act focuses on the regulation of drinking water and
control of public health risks by establishing and enforcing maximum contaminant levels
(MCLs) for various compounds in drinking water.
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5.3 STATE REGULATIONS
State requirements for production, discharge, distribution, and use of recycled water are
contained in the:
• California Water Code, Division 7 (Water Quality), Sections 1300 through 13999.16
(Water Code);
• California Administrative Code, Title 22 – Social Security, Division 4 – Environmental
Health. Chapter 3 – Water Recycling Criteria, Sections 60301 through 60475;
• California Administrative Code, Title 17 – Public Health, Division 1 – State
Department of Health Services, Chapter 5 – Environmental Sanitation, Subchapter 1,
Group 4 – Drinking Water Supplies, Sections 7583 through 7630.
In addition, guidelines for the production, distribution, and use of recycled water have been
prepared or endorsed by state agencies administering recycled water regulations. A
summary of existing and future CDPH statutes and regulations, along with the pertinent
available guidance documents, is listed in Table 5.2.
Table 5.2 Summary of California Recycled Water Regulations Recycled Water Master Plan
Carlsbad Municipal Water District
Regulations
Title 22, Division 4, Environmental Health, Chapter 3
Title 17, Division 1, California Department of Public Health, Chapter 5
Statewide Recycled Water Policy
Statutes
Health and Safety Code, Division 6, Part 1, Sanitary Districts Act of 1923, Chapter 4
Water Code, Division 7, Water Quality, Chapters 7 & 7.5
Draft Legislation
Groundwater Recharge Reuse (August 2009)
Guidance Documents
Preparation of an Engineering Report for the Production, Distribution and Use of Recycled
Water
Sources:
(1) http://www.cdph.ca.gov/healthinfo/environhealth/water/Pages/Waterrecycling.aspx (CDPH, 2009a)
(2) http://www.cdph.ca.gov/certlic/drinkingwater/Pages/Lawbook.aspx (CDPH, 2009b)
5.3.1 State Water Code
The Porter-Cologne Water Quality Control Act (CWC – Division 7), which was promulgated
in 1969, established the SWRCB as the state agency with primary responsibility for the
coordination and control of water quality, water pollution, and water rights. Nine RWQCBs
were established to represent the SWRCB regionally and carry out the enforcement of
water quality and pollution control measures. In addition, each RWQCB is required to
formulate and adopt water quality control plans, establish requirements for waste discharge
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to waters of the state, and has the authority to carry out provisions of the federal Clean
Water Act. The San Diego RWQCB has jurisdiction over the City of Carlsbad.
5.3.2 Code of Regulations – Title 22
In accordance with the requirements of Division 7 – Chapter 7 of the Water Code, CDPH
prepared Title 22 in 1975. The current requirements of Title 22, as revised in 1978, 1990,
and 2001, regulate production and use of recycled water in California. Title 22 establishes
the quality and/or treatment processes required for an effluent to be used for a specific non-
potable application, such as irrigation. The following categories of recycled water are
identified:
• Undisinfected secondary recycled water
• Disinfected secondary-23 recycled water (23 refers to the coliform count requirement
of 23 MPN/100 mL)
• Disinfected secondary-2.2 recycled water (2.2 refers to the coliform count
requirement of 2.2 MPN/100 mL)
• Disinfected tertiary recycled water
• Disinfected tertiary recycled water with conventional treatment
• Disinfected tertiary recycled water without conventional treatment
The recycled water uses allowed by Title 22 are dependent on the effluent quality of the
supply source. As the effluent of the Carlsbad Water Reclamation Facility (WRF),
Meadowlark Water WRF, and the Gafner Water Reclamation Plant (WRP) are all classified
as ‘Disinfected Tertiary Recycled Water’ per Title 22, the effluent water quality of each
meets or exceeds the criteria listed in Table 5.3.
Table 5.3 Effluent Quality Standards for Unrestricted Use per Title 22 Recycled Water Master Plan Update
Carlsbad Municipal Water District
Treatment Oxidized, Coagulated (or Filtered), and Disinfected
BOD5 Not Specified
TSS Not Specified
Turbidity 2 NTU (Daily Average)
5 NTU (Maximum during 5% of the time in a 24-hour period)
10 NTU (Maximum at any time)
Total Coliform MPN(1) 2.2/100 mL (Medium)
23/100 mL (Maximum in 30 days)
Note:
(1) No sample shall exceed an MPN (most probable number) of 240 total coliform bacteria per 100 milliliters during any 30-day period.
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The effluent from the Carlsbad WRF, Meadowlark WRF, and Gafner WRP meet or exceed
these requirements. As such, the recycled water may be used for all applications listed in
Table 5.4.
Table 5.4 Approved Use Applications for Disinfected Tertiary Recycled Water
Recycled Water Master Plan Update
Carlsbad Municipal Water District
Irrigation Uses
Food crops where recycled water contacts the edible portion of the crop, including all crop roots
Parks and playgrounds
School yards
Residential landscaping
Unrestricted-access golf courses
Food Crops, surface-irrigated, above-ground edible portion, and non contacted by recycled
water
Cemeteries
Restricted-access golf courses
Ornamental nursery stock and sod farms with unrestricted public access
Freeway landscaping
Pasture for milk producing animals for human consumption
Nonedible vegetation with access control to prevent use as a park, playground or school yard
Vineyards with no contact between edible portion and recycled water
Non food-bearing trees, including Christmas trees not irrigated less than 14 days before harvest
Fodder and fiber crops and pasture for animals not producing milk for human consumption
Seed crops not eaten by humans
Food crops undergoing commercial pathogen destroying processing before consumption by
humans
Any other irrigation uses not prohibited by other provisions of the California Code
Requirements
Supply for Impoundment
Non-restricted recreational impoundments, with supplemental monitoring for pathogenic organisms
Restricted recreational impoundments and publicly accessible fish hatcheries
Landscape impoundments without decorative fountains
Supply for Cooling and Air Conditioning
Industrial or commercial cooling or air-conditioning involving cooling tower, evaporative condenser, or spraying that creates mist
Industrial or commercial cooling or air-conditioning not involving cooling tower, evaporative condenser, or spraying that creates mist
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Table 5.4 Approved Use Applications for Disinfected Tertiary Recycled Water
Recycled Water Master Plan Update
Carlsbad Municipal Water District
Other Allowed Uses
Flushing toilets and urinals
Priming drain traps
Industrial process water that may contact workers
Structural fire fighting
Decorative fountains
Commercial laundries
Soil compaction
Dust control on roads and streets
Flushing sanitary sewers
Consolidation of backfill material around potable water pipelines
Backfill consolidation around nonpotable piping
Artificial snow making for commercial outdoor use
Commercial car washes, not heating the water, excluding the general public from washing processes
Industrial process water that will not come into contact with workers
Industrial boiler feed water
Non-structural fire fighting
Mixing concrete
Cleaning roads, sidewalks, and outdoor work areas
Other Uses Subject to RWQCB Approval
Groundwater recharge (permits issued on a case-by-case basis by the RWQCBs)
The current Title 22 requirements are also known as the “Purple Book”. The most recent
compilation of recycled water laws can be found online
[http://www.cdph.ca.gov/certlic/drinkingwater/Pages/Lawbook.aspx].
Regardless of the approved regulatory uses of Title 22 water, CMWD is limited to those
uses stated either in its individual permit, or in a general permit that covers multiple users in
the area. Currently, under Section B of CMWD’s permit, requirements are only stipulated for
landscape irrigation. Other additional uses of recycled water not identified in the permit
would need approval from the local RWQCB and CDPH office.
5.3.3 Code of Regulations – Title 17
The focus of Title 17 is protection of (potable) drinking water supplies through control of
cross-connections with potential contaminants, including non-potable water supplies such
as recycled water. Title 17, Group 4, Article 2 – Protection of Water System, specifies the
minimum backflow protection required on the potable water system for situations in which
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there is potential for contamination to the potable water supply. Recycled water is
addressed as follows:
• An air-gap separation is required on “Premises where the public water system is used
to supplement the recycled water supply.”
• A reduced pressure principle backflow prevention device is required on “premises
where recycled water is used…and there is no interconnection with the potable water
system”.
• A double-check valve assembly may be used for “residences using recycled water for
landscape irrigation as part of an approved dual plumbed use area unless the
recycled water supplier obtains approval from the local public water supplier to utilize
an alternative backflow prevention plan that includes an annual inspection and annual
shutdown test of the recycled water and potable water systems”.
5.3.4 Draft Groundwater Recharge Legislation
A draft regulation issued on August 8, 2008 specifically addresses Groundwater Recharge
Reuse. The regulations address requirements for the engineering report and monitoring
and reporting projects that use recycled water for groundwater recharge. Specific
requirements included in these draft regulation are as follows:
• Groundwater recharge can only be undertaken with disinfected tertiary recycled
water.
• Recharged recycled water must be retained underground for a minimum of six (6)
months prior to extraction for use as drinking water supply.
• Monitoring of groundwater is mandated at a location where:
– recycled water has been retained in the saturated zone for 1-3 months, but will
take at least 3 months before reaching the nearest domestic water supply well
– locations between the recharge area and the nearest down gradient domestic
water supply well
5.3.5 Statewide Recycled Water Policy
To reduce the uncertainty of the regulatory requirements for recycled water, the SWRCB
adopted a statewide Recycled Water Policy in May 2009 (SWRCB, 2009). The impetus for
the development of a statewide Recycled Water Policy stemmed from the current water
crisis and a need to streamline and expedite the use of recycled water throughout the state
in a manner consistent with existing state and federal laws. The purpose of the policy is to
provide direction to the RWQCBs and the public on the appropriate criteria for issuing
permits for recycled water projects. The policy follows Title 22 requirements and intends to
streamline recycled water use through the following measures:
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• Streamlining of Recycled Water Use Permits. The policy establishes consistent
criteria that are intended to streamline the permitting process for the vast majority of
recycled water applications. These criteria should expedite projects and allow the
RWQCBs both the time and authority to focus resources on projects with site-specific
conditions. Projects that are eligible for enrollment under a general order shall be
enrolled within 60 days. Other applications not enrolled in a general order shall be
considered for permit adoption within 120 days by the RWQCB if certain criteria are
met.
• Mandated Recycled Water Use. The SWRCB establishes a statewide mandate to
increase the use of recycled water by 200,000 acre-feet per year (afy) by 2020 and
by an additional 300,000 afy by 2030. Agencies not providing a downstream
beneficial use for recycled effluent are required to make it available on reasonable
terms. Existing legislation considers it a waste if recycled water is not utilized when
available (Water Code Sections 13550 et seq.). As part of this new policy, the
SWRCB would exercise its authority pursuant to Water Code Section 275 to enforce
the aforementioned mandates. The mandates are contingent on the availability of
sufficient capital funding for the construction of recycled water projects from private,
local, state, and federal sources.
• Salt Nutrient Management Plans. By 2014, all basins are required to develop salt
and nutrient management plans (with a two-year extension available). Such plans will
help areas meet water quality objectives on a basin wide basis instead of restricting
individual recycled water projects. The Basin Plan developed by the Santa Ana
Watershed Project Authority (SAWPA) and the Basin Plan being developed by the
San Diego County Water Authority (SDCWA) have become examples for the entire
state on how to prepare these plans. The salt and nutrient management plans work in
conjunction with the Basin Plans, which cover salts as well as other constituents, to
preserve the existing groundwater quality.
• Anti-Degradation. Projects that use recycled water for groundwater recharge are
approved depending on a basin’s capacity to assimilate the increased concentrations
of chlorides and other compounds that may be present in recycled water. If
necessary, projects would need to implement anti-degradation measures in order to
gain approval. Recycled water use projects that meet the criteria for streamlined
permitting in a basin with a salt and nutrient management plan do not need to perform
an anti-degradation investigation. These criteria are defined in detail in the Recycled
Water Policy (SWRCB, 2009).
• Funding. The SWRCB will request priority funding for storm water and recycled water
projects that augment the local water supplies from Department of Water Resources
(DWR).
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Additional measures are included in the policy to ensure that recycled water use does not
adversely affect groundwater basin quality. Such measures include:
• Monitoring of Groundwater Basins. The salt and nutrient management plans
require the use of monitoring wells to record water quality data, which needs to be
submitted to the Regional Board every three years.
• Constituents of Emerging Concern. Groundwater recharge projects are required to
test and monitor constituents of emerging concern (CECs). A Blue Ribbon Panel has
conducted a study on CECs and has prepared a Final Report, which is anticipated to
be adopted in 2011. This report has prioritized four compounds for groundwater
recharge projects based on their toxicological relevance. These four compounds are
caffeine, a female hormone (17beta‐estradiol), an antibacterial agent (triclosan), and
a disinfection by-product (N-nitrosodimethylamine). These CECs need to be
monitored to determine if the concentrations may be cause for any concern. Due to
the limited data available on CECs, there are no Action Levels (AL) or MCL
established at this time.
• Control of Incidental Runoff. Landscaping projects using recycled water are
required to control the incidental runoff of recycled water through measures that
include, but are not limited to, the following practices: installation and use of proper
sprinkler heads; an operations and management plan (can apply to multiple sites);
and application of limited irrigation during precipitation events.
If an agency producing recycled water is not using it for a beneficial use as defined in the
policy, that agency needs to provide that water to a purveyor on reasonable terms. As
CMWD is currently planning to utilize the maximum amount of available recycled water
possible, the policy does not have a significant impact on CMWD. CMWD could use the
general use permit to streamline the permitting process for future irrigation customers. In
addition, CMWD may want to monitor the impact of this policy to determine when any
additional funding assistance will be available.
5.3.6 CDPH Guidelines
To assist with the compliance with the requirements outlined in Title 22, the CDPH has
prepared a number of guideline documents. Documents relevant to the production,
distribution, and use of recycled water are:
5.3.6.1 Engineering Report
According to CWC Section 13522.5, all water purveyors that use, or propose to use,
recycled water must prepare an engineering report according to the guidelines described in
the Guideline for the Preparation of an Engineering Report on the Production, Distribution,
and Use of Recycled Water. This guideline is included in Appendix E. This report must be
submitted to the appropriate RWQCB and CDPH. The report must describe the recycled
water production process, including raw and treated water quality, treatment process, plant
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reliability features, supplemental water supply, monitoring program, and contingency plan to
prevent distribution of inadequately treated water. The report must include maps of the
distribution system and describe how the system will comply with CDPH and American
Water Works Association (AWWA) guidelines and Title 17. The report must also include
maps and descriptions of proposed use areas, types of uses proposed, people responsible
for supervising the uses, design of the user systems, and the proposed user inspection and
monitoring programs.
5.3.6.2 Cross-Connection Control
The Manual of Cross-Connection Control/Procedures and Practices was prepared by
CDPH in 1981 (and updated periodically) and focuses on establishing a cross-connection
control program to protect the public against backflow and back-siphonage of
contamination. Main elements of the manual include areas where protection is required,
causes of backflow, approved backflow preventers, procedures, installation, and
certification of backflow preventers and water shutoff procedures for conditions that pose a
hazard to the potable water supply.
It should be noted that the proposed revisions outlined for the Draft California 2010
Plumbing Code – Chapter 16 – Part II dated May 13, 2009 (see Appendix B), prohibit the
use of backflow preventers between potable and recycled water systems and specifies that
a recycled water system shall not have any connections to a potable water system
(Section 1613.0 under A).
5.4 REGIONAL WATER QUALITY CONTROL BOARD
While CDPH provides input to protect public health, the RWQCB created provisions in a
permit for the protection of beneficial uses of water and the protection of water quality.
These provisions are based on the Water Quality Control Plan the RWQCB has adopted,
otherwise known as the Basin Plan. The Basin Plan is the RWQCB guide for the protection
of the beneficial uses of water and the enhancement of water quality. This document
provides water quality objectives for continued beneficial use of water resources. This
study’s area of interest falls within Basin Plan hydrological unit 904.00, which is divided into
five hydrologic subareas (HSAs). A map of the Basin location is shown in Figure 5.1. For
this hydrologic region, the groundwater constituent limits from the Basin Plan are listed in
Table 5.5. Groundwater constituent concentrations cannot exceed these limits more than
10 percent of the time during any one-year period.
21-Carlsbad510Fig5.1-8308A00.ai
Carlsbad Watershed
FIGURE 5.1
CARLSBAD MUNICIPAL WATER DISTRICT
Loma Alta
Buena Vista Creek
Agua Hedionda
Encinas
San Marcos
Escondido Creek
904.1
904.2
904.3
904.4
904.5
904.6
Hydrologic Unit 904.10 - 904.63
Hydrologic Areas:
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Table 5.5 Basin Plan Groundwater Quality Objectives
Recycled Water Master Plan Update
Carlsbad Municipal Water District
Constituent (mg/L or as noted)
El Salto
HSA (904.21)
Los Manos
HSA(1,2,3)
(904.31)
Encinas
HSA(1,4)
(904.40)
San Marcos
HSA(5) (904.50)
Batiquitos
HSA(1,5,6)
(904.51)
Total Dissolved Solids 3,500 3,500 3,500 1,000 3,500
Chloride 800 800 800 400 800
Sulfate 500 500 500 500 500
Percent Sodium 60% 60% 60% 60% 60%
Nitrate (as NO3) 45 45 45 10 45
Iron 0.3 0.3 0.3 0.3 0.3
Manganese 0.05 0.05 0.05 0.05 0.05
Methylene Blue Active
Substances
0.5 0.5 0.5 0.5 0.5
Boron 2.0 2.0 2.0 0.75 2.0
Fluoride 1.0 1.0 1.0 1.0 1.0
Notes:
Source: RWQCB, San Diego Region, Comprehensive Quality Control Plan for the San Diego Basin
(1) The water quality objectives do not apply westerly of the easterly boundary of Interstate 5.
(2) Notwithstanding the Basin Plan water quality objectives, the Regional Board will regulate discharges in HAS 904.31 in a manner that will protect the waters produced by existing operating wells.
(3) The water quality objectives apply to the portion of HSA 4.31 bounded on the west by the easterly boundary of El Camino Real.
(4) Detailed salt balance studies are recommended for determining limiting mineral concentration levels for discharge. Upon completion of the salt balance studies, significant water quality objective revision may be necessary. In the interim period of time, projects involving groundwater recharge with water quality inferior to
the listed values may be permitted following individual review and approval by the Regional Board if such projects do not degrade existing groundwater quality to the aquifers affected by the recharge.
(5) The water quality objectives do not apply to HSA 904.51 between Highway 78 and El Camino Real, and to all
lands that drain to Moonlight Creek and Encinas Creek. The objectives for the remainder of the HSAs are shown.
(6) The water quality objectives apply to the portion of HSA 904.51 bounded on the south by the north shore of
Batiquitos Lagoon, on the west by the easterly boundary of Interstate 5 right-of-way, and on the east by the easterly boundary of El Camino Real.
When issuing a recycled water reclamation or discharge permit, the RWQCB considers the
water quality objectives in the Basin Plan. Typically, constituents cannot exceed the limit set
forth by the Basin Plan for each hydrologic region. For Carlsbad, the water quality limits for
the Carlsbad WRF, Meadowlark WRF, and Gafner WRP are defined in the respective
wastewater discharge permits, which are included in Appendix E. The Carlsbad WRF
master permit (Order No. 2001-352) includes the water quality limits that apply to the entire
CMWD service area. These limits are summarized in Table 5.6.
When comparing Table 5.5 and Table 5.6, it can be concluded that the Master Reclamation
Permit requirements are more stringent for most constituents than the goals set forth in the
Basin Plan.
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Table 5.6 Master Reclamation Permit Requirements
Recycled Water Master Plan Update
Carlsbad Municipal Water District
Constituent
Daily Maximum
(mg/L)
30-Day Average
(mg/L)
12-Month Average
(mg/L)
Total Dissolved Solids (TDS) 1,200 - 1,100
Chloride 400 350 -
Sulfate 400 - 350
Boron 0.75 0.75 0.75
Iron 0.4 0.3 0.3
Manganese 0.06 - 0.05
Fluoride - - 1.0
Methylene Blue Active Substances (Surfactant) - - 0.5
Note:
Source: Master Reclamation Permit for Carlsbad Water Recycling Facility (RWQCB, 2001), included in Appendix E.
The Master Reclamation Permit issued to CMWD also contains numerous requirements for
the purveyance of recycled water. These include:
• Requirements for the initiation of recycled water service to a new customer including:
– Develop rules and regulations governing the design and construction of
recycled water use facilities (this is already in place)
– Develop a compliance inspection program (this is already in place)
– Submit irrigation plans to the CDPH and/or DEH for new connections
• Requirements subsequent to the initiation of recycled water service but prior to the
delivery of recycled water including:
– Submit a report to the CDPH and DEH certifying that the new user site
conforms with documentation previously sent to the CDPH and DEH
– Conduct a complete cross-connection shut down test for each new use site
– Verify that reclamation treatment facilities meet RWQCB requirements
• Ongoing requirements for all reuse sites after the start of service including:
– Enforce recycled water rules and regulations
– Conduct recycled water reuse site compliance inspections
– Notify the DEH and CDPH of any recycled water backflow into the potable
system
– Maintain a current list of all on-site recycled water supervisors
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5.5 LOCAL REGULATIONS
Local regulations discussed in this chapter include regulations from San Diego County and
CMWD.
5.5.1 County of San Diego Regulations
The County of San Diego also has specific regulations governing the inspection and
implementation of recycled water connections, contained in the Recycled Water Plan Check
and Inspection Manual (DEH 2001 Edition). In San Diego County, the plan check and
inspection responsibilities are shared between CDPH and the County of San Diego DEH.
CDPH is responsible for the plan review of treatment processes, treatment plants, main
conveyance systems, and proposed new and unusual uses of recycled water. In
conjunction with CMWD staff, the DEH is responsible for plan review and inspections of all
recycled water use sites.
Off-Site Requirements:
• Minimum Separation/Proximity of Utilities: Vertical separation requirements must
be met if the pipeline maintains a positive pressure during the day.
• Horizontal Separation: A 10-foot horizontal separation must be maintained between
a recycled water pipeline and a sewer main or water pipeline. Separations smaller
than 10 feet need approval from CMWD and/or the CDPH depending on the
separation distance. The state now only requires a 4-foot horizontal separation
between a disinfected tertiary treated recycled water pipeline and a potable pipeline.
• Vertical Separation: A potable water line must be installed at least 1 foot above a
recycled water line, which must be installed at least 1 foot above a sanitary sewer.
On-Site Requirements:
• Separation: At the user site, the separation of utilities is similar to the off-site
requirements, but individual purveyors may modify the required on-site distances.
Areas of potable water irrigation and recycled water irrigation must be physically
separated either by distance, concrete mow strips, or other approved methods, such
as fences or walls.
• Minimum Depth: The minimum pipeline depth is defined in the City’s landscape
manual and is as follows:
– Pressured pipeline less than 3 inches in diameter require 18-inch cover
– Pressured pipeline between 3 and 5.5 inches in diameter require 24-inch cover
– Pressured pipeline of 6 inches and greater in diameter require 36-inch cover
– Non pressured pipelines require 12-inch cover
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• System Identification. All appurtenances related to the system (sprinkler heads,
valve boxes, tags, quick couplers, etc.) must be color coded purple. All valve boxes
shall be tagged with recycled water tags. On retrofit jobs, underground piping does
not need to be changed.
• Sprinkler Location. Sprinklers located close to swimming pools, eating areas, and
sand-filled play areas for children should be of the bubbler non-spray type or have
adjustable nozzles. Alternatively, sprinklers can be located so that these areas are
not oversprayed. 180-degree turf sprinkler heads adjacent to sidewalks are not
acceptable since they overspray and cover 190 degrees.
• Sprinkler Coverage. Sprinklers must only cover the designated area. Measures
need to be taken to avoid misting and wind blown mist.
• Drinking Fountains. Drinking fountains must be protected from recycled water
runoff, spray, or mist.
• Ponds. If a pond is receiving recycled water, potable water to the pond must be
delivered through an air gap. Ponds can have fountains provided that the County’s
design guidelines are followed.
• Food Establishments. Recycled water should not be installed near drive-through
windows or outdoor patio eating areas.
• Hours of Irrigation: The County’s Manual describes standard plan notes requiring
hours for irrigation to be between 10:00 p.m. and 6:00 a.m. However, if the recycled
water meets tertiary treatment standards, the local water authority may modify the
hours for irrigation under the qualification that irrigation during public use periods is
supervised. Thus, CMWD could modify the hours of irrigation for customer sites
where supervision during public hours is possible.
• Cross-Connection Testing: The County’s manual also specifies testing procedures
and frequency to ensure that there are no cross connections with the potable water
system.
5.5.2 District Mandatory Use Ordinance
CMWD currently has an ordinance mandating the use of recycled water in accordance with
California Water Code, Sections 461, 13510, and 13550. This ordinance is included in
Appendix E of this report and summarized below.
The ordinance recognizes that recycled water can reduce dependence on imported water
and that certain uses of potable water may pose a nuisance where recycled water is
available. Accordingly, the ordinance declares that recycled water shall be used within the
jurisdiction wherever it is economically justified, financially and technically feasible, and
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consistent with legal requirements for preservation of public health, safety and welfare, and
the environment.
CMWD is responsible for making the preliminary determination as to which existing potable
water customers shall be converted to recycled water. Notice of this determination is sent to
the customer, and upon receipt the customer has 90 days to submit an implementation plan
to CMWD. The cost for the preparation of this plan should be paid by the customers with
the exception of customers that decide to ask CMWD to prepare this plan and are willing to
sign an acknowledgement to accept and install the proposed improvements in the plan
prepared by CMWD. Once approved, the plan must be implemented within six months. The
customers have 30 days to contest any preliminary determination after notice of receipt.
As part of the application process for a new development project, CMWD staff review
planning documents to determine if the proposed development requires recycled water, if
the proposed development should include provisions for future recycled water use, or if the
development is considered suitable for recycled water. Provisions for a current or future
recycled water connection may be required as a condition of approval. In addition,
applications for remodeling of a property may also be reviewed for recycled water use
feasibility. If the property in question is considered suitable for existing or future recycled
water use, the use of recycled water may be conditioned on the remodeling application.
The ordinance also specifies CMWD policies for requested recycled water service, plan
approval, field inspection, temporary use of potable water (until recycled water is available),
and the recycled water rate.
The ordinance is adequate for CMWD’s purposes as it defines CMWD’s authority in
requiring recycled water use, clearly lists criteria for identifying potential users, and outlines
the process for new customer connections.
5.5.3 District Regulations and Design Standards
CMWD has also developed rules and regulations for the use of recycled water. These rules
and regulations are in included in the following three chapters of CMWD’s General Design
Standards, Volume 2 – Potable and Recycled Water Standards (CMWD, 2010):
• Chapter 2 – Rules and Regulations for Use of Recycled Water: This chapter sets
forth the general requirements and conditions as well as the administrative
requirements pertaining to the use of recycled water in CMWD as required by the
Master Reclamation Permit, the CDPH, and the DEH.
• Chapter 3 – Design Guidelines and Procedures: This chapter provides the design
procedures, planning and design criteria, as well as the specifications for the location,
type, and size of water facilities.
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• Chapter 5 – Requirements for Onsite Recycled Water Systems: This chapter
defines the design requirements, construction specifications, and operational
requirements for onsite (private) recycled water systems.
5.6 FUTURE REGULATORY DEVELOPMENTS
Future regulatory considerations for the use of recycled water consist of the anticipated
updates to the Draft Groundwater Recharge Reuse Regulations and the 2010 California
Plumbing Code. In addition, there are developments on the regulation of endocrine
disrupting compounds (EDCs) and other CECs.
5.6.1 Groundwater Recharge
As described in Section 5.3.4, the CDPH issued Draft Groundwater Recharge Reuse
Regulations in August 2008 that contain treatment requirements for projects with an indirect
potable reuse or recharge component (CDPH 2008). These requirements have been
implemented for past projects and require such constraints as a minimum underground
detention time. The Title 22 Regulations currently call for RWQCBs to review groundwater
recharge projects on a case-by-case basis with input from CDPH. These draft regulations
will be finalized in the future. Further information regarding the development of these draft
regulations can be found on the CDPH website (CDPH, 2009).
5.6.2 Updates to the 2010 California Plumbing Code
The California Plumbing Code is being updated to relax the restrictive rules for installing
dual plumbing for indoor recycled water use, as well as gray water. These changes pertain
to Chapter 16 of Title 24, Part 5 of the California Code of Regulations.
The code revisions for recycled water were approved by the Building Standards
Commission and will be part of the 2010 Code. The new rules remove some of the
restrictions on the installation of recycled water pipe in buildings. The major features of the
new dual plumbing rules are:
• Recycled water pipe can now run in the same wall/ceiling cavity as potable pipe.
• The labeling requirements for purple pipe are relaxed.
• The annual inspection is a visible inspection, followed by a cross-connection test if
there is reason to believe there is a cross-connection, rather than an automatic cross-
connection test each year.
• The use of potable water for backup supply or makeup water is not allowed. Recycled
water systems must be completely separated from potable water systems.
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5.6.3 Constituents of Emerging Concern
Recent advances in technology have allowed the detection of constituents that were
previously undetected in the environment. Many of these constituents are classified as
CECs since they are suspected of possibly posing a public health or ecological risk. CECs
are not currently regulated by the Environmental Protection Agency (EPA), but many of
these constituents are candidates for future regulations. As more scientific information
becomes available, the EPA may impose regulations on some of these constituents. CECs
include personal care products and pharmaceutical products. Many of these CECs are also
considered EDCs.
The primary concern of CEC is indirect potable reuse. As CMWD does not practice indirect
potable reuse, CECs should not be a significant concern for CMWD at this time.
Nevertheless, CMWD should be aware of CECs since the public at large has expressed
concern with the potential for coming in contact with CECs through contact with edible
crops irrigated by recycled water.
As stated in Section 5.3.5, a Blue Ribbon Panel has prioritized four compounds for
groundwater recharge projects based on their toxicological relevance. These four
compounds are caffeine, a female hormone (17beta-estradiol), an antibacterial agent
(triclosan), and a disinfection by-product (N-nitrosodimethylamine).
In addition, other CECs are identified as viable performance indicator compounds, which
differ by the type of reuse practice. However, none of the chemicals for which measurement
methods and exposure data are available exceeded the threshold for monitoring priority.
For irrigation applications, the Panel therefore recommends monitoring emphasis be placed
on use of indicator CECs that can demonstrate that the treatment processes employed are
effective in removing CECs.
5.6.4 Endocrine Disrupting Compounds
In recent years, there has been heightened scientific awareness and public debate over
potential impacts that may result from exposure to EDCs. Humans, fish, and wildlife species
could potentially be affected by sufficient environmental exposure to EDCs. This discussion
is provided to briefly communicate what is currently known about EDCs and to describe
their position within California’s recycled water regulations.
EDCs can be either natural or anthropogenic contaminants, which are chemicals that have
been introduced to the environment by the activity of man. Plants, such as soybeans and
garlic, produce natural EDCs as a defense mechanism. However, most EDCs are
man-made synthetic chemicals, which are unintentionally released into the environment.
Certain drugs, such as birth control pills, intentionally alter the endocrine system.
Categories and sources of substances that are potential EDCs are presented in Table 5.7.
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Table 5.7 Potential Endocrine Disrupting Compounds
Recycled Water Master Plan Update
Carlsbad Municipal Water District
Category Examples of Substances Examples of Uses Examples of Sources
Polychlorinated
Compounds
Polychlorinated dioxins,
Polychlorinated
biphenyls
Industrial production
of by-products
(mostly banned)
Incineration, landfill
Organochlorine Pesticides DDT, Dieldrin, Lindane Insecticides (many phased out) Agricultural runoff
Other Pesticides
(current use)
Atrazine, Trifluralin,
Permethrin
Pesticides Agricultural runoff
Organotins Tributyltin Antifoulants on ships Harbors
Alkylphenolics Nonylphenol Surfactants (and their metabolites) Industrial and municipal effluents
Phthalates Dibutyl phthalate,
Butylbenzyl phthalate
Plasticizers Industrial effluent
Hormones 17-beta estradiol, Estrone Produced naturally by animals Municipal effluents
Synthetic Steroids Ehynylestradiol Contraceptives Municipal effluents
Phytoestrogens Isoflavones, Ligands,
Coumestans
Present in plant
material
Pulp mill effluents
Source: Canadian Wildlife Service, Pacific Wildlife Research Center (CWS, YEAR).
Regulations Pertaining to EDCs
In 1996, new legislation required that the U.S. EPA “determine whether certain substances
may have an effect in humans that is similar to an effect produced by a naturally occurring
estrogen or other such endocrine effect.” In response, the EPA developed the Endocrine
Disrupter Screening and Testing Advisory Committee. In June 2008, they issued a draft
white paper on how criteria for the synthetic birth control estrogen ethinyl estradiol might be
developed in the future.
Although some chemicals have been conclusively determined to be EDCs, many chemicals
are termed “suspect” because there is not enough data to make a decisive determination
regarding their endocrine disrupting characteristics. Some known EDCs (e.g., PCBs, DDT,
chlordane) are already regulated via surface water quality standards or drinking water
standards based on their toxicological and carcinogenic effects. However, no water quality
standards currently exist for natural and synthetic estrogens or related pharmaceutical
chemicals. Based on the current state of knowledge regarding dose-response relationships
of EDCs for various organisms at the low-levels in which they can occur in surface waters, it
is likely to be a number of years, possibly many years, before any such standards are
promulgated.
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The EPA and other stakeholders looked at 7,500 substances and in December 2009 the
EPA released its third contaminant candidate list (CCL3). The CCL3 includes
116 substances (104 chemicals and 12 microbiological contaminants) which are not
currently regulated in drinking water by the federal government but may be considered for
future regulation under the Safe Drinking Water Act (SDWA). The final CCL3 includes,
among others, pesticides, disinfection byproducts, chemicals used in commerce,
waterborne pathogens, pharmaceuticals, and biological toxins.
5.7 RECOMMENDATIONS
CMWD currently abides by the stipulations imposed by CDPH through the Master
Reclamation Permit, and DEH through CMWD standards found in Volume II Potable and
Recycled Water Standards. Nevertheless for one DEH requirement, a physical separation
between areas of irrigation with recycled and potable water, CMWD could add a qualifying
phrase to Item 5.1.3.E of Chapter 5 of the standards to ensure that this physical separation
is applied to both large, constantly pressurized pipes and small, intermittently pressurized
pipes. After the start of the sentence, “Potable and recycled lines,” CMWD could add the
qualifier, “including irrigation laterals.” This could help avoid situations where the physical
separation exists for offsite pipes, but not for onsite irrigation laterals.
CMWD staff have mentioned that significant effort is expended complying with the
increased oversight requirements of the County. While this regulatory oversight is outside
the control of CMWD, decreasing the amount of regulatory oversight would increase
CMWD staff’s productivity and efficiency.
In addition, CMWD will want to monitor funding opportunities that may result from the new
Recycled Water Policy. Such funding could become available as the State’s budget
situation improves.
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Chapter 6
HYDRAULIC MODEL
This chapter presents an overview of the activities undertaken to develop and calibrate the
hydraulic model for Carlsbad Municipal Water District’s (CMWD) recycled water distribution
system. This chapter contains the following sections:
• Hydraulic Modeling Overview – This section explains the purpose of hydraulic models
and modeling software selection.
• Existing System Model Creation – This section describes the model development and
the data and processes used to create each hydraulic model.
• Existing System Model Calibration – This section describes the processes used to
gather field data and calibrate each model in order to establish a level of confidence
in the model results.
• Future System Model Creation – This section describes the additions made to the
calibrated model to analyze future system expansion opportunities.
Detailed information on the calibration of each of the models is included in Appendix F,
Model Calibration Results. Additional information on the use of the models is included in
Appendix G, Model Manual.
6.1 HYDRAULIC MODELING OVERVIEW
Innovations in personal computing and the large selection of software have made network
analysis modeling efficient and practical for virtually any water system. Hydraulic modeling
is an important tool for analyzing a water system. Hydraulic models can simulate existing
and future water systems, identify system deficiencies, analyze impacts from increased
demands, and evaluate the effectiveness of proposed system improvements, including
those within capital improvement plans. In addition, a hydraulic model provides both the
engineer and water system operator with a better understanding of the water system
dynamics. Hydraulic models are typically composed of three main parts:
• The data file that stores the geographic location of facilities. The geographic data file
provides water system facility locations and is typically represented as an AutoCAD or
geographic information systems (GIS) file. Elements used in this file to model system
facilities include pipes, junction nodes (connection points for pipes and location of
demands), control valves, pumps, tanks, and reservoirs.
• A database that defines the physical system. The database for CMWD’s model is
linked to the geographic data file. The database includes water system facility
information such as facility size and geometry, operational characteristics, and
production/consumption data.
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• A computer program “calculator”. This calculator solves a series of hydraulic
equations based on information in the database file to define and generate the
performance of the water system in terms of pressure, flow and operation status.
The key to maximizing benefits from the hydraulic model is correctly interpreting the results
so the user understands how the water distribution system is affected by the various
components of the model. This understanding enables the engineer to be proactive in
developing solutions to existing and future water system goals and objectives. With this
approach, the hydraulic model is not only used to identify the adequacy of system
performance, but is also used to find solutions for operating the water system according to
established performance criteria.
Developing an accurate and reliable computer model begins with entering the best
available information into the database and calibrating the model to match existing
conditions in the field. Once the model has been calibrated, it becomes a valuable tool to
evaluate operational problems and to plan distribution system improvement projects.
6.1.1 Hydraulic Model Selection
Several software programs are widely used to model distribution systems. The variety of
program capabilities and features makes the selection of a particular software program
generally dependent upon three factors: user preference, the requirements of the particular
water distribution system, and the cost associated with the software.
CMWD has selected H2OMAP® Water, developed by MWH Soft, Inc., for the hydraulic
modeling of its recycled water distribution system.
6.1.2 Previous Hydraulic Model
CMWD’s initial hydraulic model of its recycled water distribution system was developed in
2000 as a part of the Encina Basin Recycled Water Distribution System Study (JPA, 2000)
using H2ONET® Version 2.0.
The hydraulic model provided to Carollo Engineers at the beginning of this project was
developed by CMWD staff in H2OMAP® Water.
6.2 EXISTING SYSTEM MODEL CREATION
CMWD provided GIS layers containing relevant information concerning its pipeline network.
Since the level of detail and topology of CMWD’s GIS layers was judged to be more
representative of the recycled water distribution system than the previous hydraulic model,
CMWD’s GIS layers were imported into the hydraulic model rather than the pipelines from
the previous hydraulic model. Facilities and controls were then adapted from the previous
hydraulic model. In summary, the model creation process involved the following steps:
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1. Link Creation. Links were created from CMWD’s GIS layers of pipeline elements to
represent CMWD’s recycled water system.
2. Node Creation. Nodes were automatically generated at the intersections of pipeline
segments. Individual nodes representing specific components of the City’s recycled
water system such as tanks and reservoirs were added.
3. Attribute Data Input. Unique attribute data was assigned to each link and node.
4. Facility Creation. Facilities were imported from the previous hydraulic model and
verified through discussions with CMWD staff.
5. Operational Data. Based on the previous hydraulic model as well as discussions with
CMWD operations staff, control parameters were assigned to the appropriate links
and nodes.
The model operates according to the operational and physical attributes assigned to each
node and link. This information is used to simulate flows and pressures within the system
as predicted by the model’s mathematical equations. A screenshot of the hydraulic model is
shown in Figure 6.1.
Figure 6.1 Screenshot of Hydraulic Model
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6.2.1 Model Links
Hydraulic models consist of links and nodes to model representations of physical system
components of a distribution system. Links are used to represent pipes, pumps, and control
valves. Pipeline segments represent the actual transmission or distribution water pipelines.
In the attribute table for each pipe, data typically includes diameter, length, C-factor, and
pressure zone. The model calculator uses the attribute data to determine increases or
decreases in energy levels across the link. Some of the reported output data that the model
calculates for links include flows, velocities, head loss, and changes in hydraulic grade line.
6.2.2 Model Nodes
Nodes represent the connections between links and may act as either a supply source,
such as a reservoir or tank, or a customer demand. Nodes also define the boundaries of
each link and separate links that may contain different attributes. Each node also has an
elevation that fixes the elevations of the connecting link elements. Attribute data associated
with each node typically includes elevation, water demand, and pressure zone. The model
calculates system pressures, hydraulic grade lines, demands, and water quality parameters
at each node.
6.2.3 Demand Allocation
Demands were initially allocated based on historical billing records for the calendar year
2008. Demands from customer meters were allocated to the existing junction within the
hydraulic model nearest the location of the meter in the City’s GIS layer of meters.
Demands were updated to 2010 demands for the five largest users, and scaling of the
overall demands for remaining users.
Locations of meters for the five largest users were imported directly from the City’s GIS
layer of meters, giving the five largest users their own nodes. These meters are assigned
the same Meter ID as the City’s GIS layer and the name of the customer is included in the
Description field for the junction element.
As shown in Table 6.1, in addition to the demands for all of CMWD’s pressure zones, a
demand of 486 gpm (0.7 mgd) was assumed for OMWD to account for the level of Mahr
Reservoir. Also, 120 gpm (0.2 mgd) of CMWD’s recycled water demand represents the La
Costa Resort and Spa south golf course fed by Gafner WRP and is isolated from the rest of
the distribution system.
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Table 6.1 Summary of Demands by Pressure Zone
Recycled Water Master Plan Carlsbad Municipal Water District
Pressure Zone
Elevations Served
(ft-msl)
Average Day Demand(1)
(gpm)
Average Annual Demand(1)
(afy)
660 240' to 460' 193 311
580 200' to 430' 142 229
550 200' to 430' 453 731
384 20' to 380' 1,476 2,381
318 50’ to 80’ 24 39
Subtotal 50' to 460' 2,287 3,690
La Costa Golf Course 61' 120 194
Subtotal (CMWD’s System) 50' to 460' 2,407 3,884
OMWD N/A 486 784
Total in Hydraulic Model 50' to 460' 2,893 4,668
Note:
(1) Demands are based on 2008 data, as the spatial data for calendar year 2009 was not available at the time of this report preparation.
6.2.4 Elevation Allocation
Elevations were linearly interpolated to all junctions from the City’s GIS layer of ground
elevation contours. This contour layer has 2-foot intervals.
6.2.5 Attribute Data Information
For junction elements, attribute data was added for the fields DMD_NODE, FACILITYID,
FAC_NODE, LARGEUSER, STATUS, LOGGER, and LOGGERID. The LOGGER and
LOGGERID fields were added as a part of the calibration process. Descriptions for the
junction fields added to the model, as well as their sources, are shown in Table 6.2.
For pipeline elements, attribute data was imported from the City’s GIS pipeline layer for the
fields Diameter, Material, Zone, Year of Installation, and Facility ID. Descriptions for the
fields added to the pipeline elements in the model, as well as their sources, are shown in
Table 6.3.
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Table 6.2 Junction Attribute Data Fields
Recycled Water Master Plan Carlsbad Municipal Water District
Field Name Description Valid Entries Source
DMD_NODE Indicates if a demand is placed on
the junction.
Boolean
(Yes or No)
Demand Allocation
FAC_NODE Indicates if the junction is a part of
a facility.
Boolean
(Yes or No)
Generated by
Consultant
LARGEUSER Indicates if the junction represents the meter of a large user. Boolean (Yes or No) City’s meter GIS layer
STATUS Indicates whether a facility is
active in the existing system.
ACT, ABAN City’s pipeline GIS
layer: “STATUS” Field
Table 6.3 Pipeline Attribute Data Fields Recycled Water Master Plan
Carlsbad Municipal Water District
Field Name Description Valid Entries Source
DIAMETER Diameter of pipeline. Integers City’s pipeline GIS layer:
“Diam” Field
MATERIAL Pipeline material. ACP, CML&C, DI, STL, PVC
(with class)
City’s pipeline GIS layer: “PIPETYPE” and
“PIPECLASS” Fields
ZONE Pipeline pressure zone. 318, 384, 550,
580, 660
City’s pipeline GIS layer:
“PressZone” Field
YR_INST Year pipeline installed. Adapted from year of “ASBUILT” field. For
pipelines with unknown “ASBUILT” field, used “SIGNDATE” field.
Integer, 9999 used for
unknown years.
City’s pipeline GIS layer: “ASBUILT” and
“SIGNDATE” Fields
FACILITYID Unique identifier. Not included on
pipelines not from the City’s GIS.
WM##### City’s pipeline GIS layer:
“FacilityID” Field
FACILITY Indicates whether an element is
part of a facility (i.e., pipeline segments used for modeling
purposes rather than actual pipeline in the ground).
Boolean
(Yes or No)
Generated by Consultant
STATUS Indicates whether a facility is
active in the existing system.
ACT, ABAN City’s pipeline GIS layer:
“STATUS” Field
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6.2.6 Operational Controls
Operational controls were initially obtained from the previous hydraulic model. These
controls were discussed with operation staff during the Operations Workshop. The updated
system controls discussed in the workshop are presented in Table 6.4.
Table 6.4 Operational Controls Recycled Water Master Plan
Carlsbad Municipal Water District
Facility Facility Type Control Details
Carlsbad
WRF
Discharge
Pump Station • Activated by operator.
• Generally two pumps on from 10:00 p.m. to 6:00 a.m.
• Third pump activated when necessary.
Carlsbad WRF Equalization Basin • During the winter and wet weather events, the equalization capacity is used to buffer effluent, as the
ocean outfall capacity is limited.
• During the summer, the equalization basin capacity is
used to buffer diurnal demand variations.
Avenida Encinas PRV Pressure Regulating
Station
• 3-inch diameter PRV set at 113 psi.
• 8-inch diameter PRV set at 108 psi.
Twin D Booster Pump
Station • Four VFD pumps able to be controlled by flow and pressure.
• Pumps would turn off if the D Tanks’ levels fall below 10 feet.
Twin D Ralph Valve • 10-inch diameter FCV/PSV(1) with maximum capacity
of 3,500 gpm.
Twin D Potable Makeup Connection • 8-inch diameter PSV(2) with capacity of at least
3,000 gpm.
• PSV is set to 74 psi.
La Costa /
Poinsettia
PRV
Pressure
Regulating
Station
• 6-inch diameter PRV set at 90 psi.
• 8-inch diameter PRV set at 85 psi.
• Pressure Relief Valve (not modeled).
• This station opens automatically during periods of high
demand to supply Zone 384(3).
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Table 6.4 Operational Controls
Recycled Water Master Plan Carlsbad Municipal Water District
Facility Facility Type Control Details
Bressi PS Pump Station • Three VFD pumps controlled primarily by pressure and secondarily by flow.
• One 7.5 hp VFD jockey pump operated during periods of low demand(3).
• 8-inch diameter Pressure Relief Valve set at 85 psi (not modeled).
• This station opens automatically during periods of high demand to supply Zone 384(3).
Faraday PRV Pressure
Regulating Station
• 6-inch diameter PRV.
• 10-inch diameter PRV.
• Settings for both valves are above an HGL of 384 to assist the Twin D tanks in the north portion of the 384
Zone.
Calavera PS Pump Station • Three VFD pumps with a hydro-pneumatic tank.
• One 5 hp VFD jockey pump operated during periods of
low demand(3).
• 8-inch diameter Pressure Relief Valve (not modeled).
Note:
(1) As discussed in Chapter 2, the valve is a combination rate of flow, pressure sustaining, and solenoid control valve, but is controlled by a SCADA based on tank level and demand. (2) As noted in Chapter 2, the valve is normally closed and can be operated remotely through SCADA.
(3) Controls or facilities were modified after calibration to reflect changes in how CMWD staff operate the system.
Controls for parameters not specified from the operations workshop were either based on
the SCADA printouts provided by CMWD, adapted from the previous hydraulic model, or
assumed from the existing system HGL.
6.3 EXISTING SYSTEM MODEL CALIBRATION
The purpose of the hydraulic computer model is to estimate or predict how the water
system will respond under a given set of conditions. One way to test the accuracy of the
computer model is to create a set of known conditions in the water system and then
compare the results observed in the field against the results of the computer model
simulation using the same conditions. Field testing of the system and pulling SCADA
information during that time can be a profound tool for verifying data used in the hydraulic
computer model and gaining greater understanding of how the water system operates.
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Field testing and SCADA review can identify errors in the data for the computer model, or it
may reveal an unknown condition in the field; for example, valves reported as being open
might actually be closed (or vice versa), or an obstruction could be discovered in a pipeline.
This can also correct erroneous model data such as incorrect pipe diameters or
connections between pressure zones. Data obtained from this process can be used to
determine appropriate roughness coefficients for pipe groups based on specific information
about the pipes. The roughness coefficient can vary with age and pipe material, as well as
by system. Therefore, these parameters were used in combination with the field testing and
SCADA results to help assign appropriate friction coefficients.
6.3.1 Field Data Gathering
The field testing consisted of placing pressure loggers at various locations throughout the
system. A collection of SCADA data of the system facilities during that time was
downloaded. A field testing plan was developed in conjunction with CMWD staff to make
efficient use of field personnel and equipment. The field data gathering plan was
implemented in October 2009.
For the purpose of model calibration, 15 pressure loggers were installed in the field to
record system pressures. The locations of the pressure loggers are shown on Figure 6.2
and listed in Table 6.5. The detailed approach to perform field testing and obtain SCADA
data for this system is provided in the “Field Testing Plan - Carlsbad Recycled Water
System” (Field Testing Plan), which is included in Appendix D. Data collected from the field
testing during this time is summarized in Appendix E. This data was compared to the
modeling results to determine the level of calibration.
The pressure loggers were set in place the evening of October 12, 2009 and recorded
pressure 24 hours a day through the evening of October 21, 2009, when the loggers were
removed and data downloaded. CMWD staff then pulled SCADA data from their system
during this time. Unfortunately, a server error rendered automatic data gathering of the
SCADA system inoperable for the time period. Data was manually copied by CMWD staff
for the night of October 16, 2009, through the morning of October 18, 2009. Based on the
available data, October 17, 2009 was then selected as the calibration day for the Extended
Period Simulation (EPS) model calibration. The SCADA data pulled during this time is listed
in Table 6.6.
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Table 6.5 Pressure Logger Locations
Recycled Water Master Plan Carlsbad Municipal Water District
Pressure Logger
Number Location
Pressure
Zone Comments
E6 Embarcadero Lane at Avenida Encinas 318
3 Alicante Rd. south of Lapis Rd. 384
E1 In front of 6827 Sand Aster Dr. 384
E2 1440 Sapphire Dr. 384
E5 Dahlia Way at Lowder Lane 384
E8 Armada Dr. southwest of Legoland Dr. 384
2 5927 Landau Ct. 384 Bad readings;
removed from
analysis.
X The Crossings Dr. south of Grand Pacific Dr. 384
XX Wind Trail Way at Glen Ave. 384
12 Town Garden Rd. southwest of Alicante Rd. 550
17 Whiptail Loop and Caribou Ct. 550
E7 Rancho Santa Fe Rd. and Avenida Soledad 550
E4 Cay Dr. at Promontory Place 580 Hydro-pneumatic
Zone
1 Rancho Bravado at Paseo Acampo 660 Hydro-pneumatic Zone
21 Lionshead Ave. at Eagle Dr. 660 Hydro-pneumatic
Zone
Note: Pressure Logger Number corresponds with numbers shown on Figure 6.2.
Agua HediondaLagoon
Twin "D" Tanks
E
l
C
a
mi
n
o
R
e
alElm A veMarron Rd
Carlsbad Blvd
Highla
n
d Dr
A londra W ayPaseo Nort
eCollege BlvdPalomar Airport
Aviara Pkwy El Fuerte StCosta AvePoinsettia LnTam arack AveCannon Rd
Calle Barcelona
"C" Tank
Carlsbad WRF
Gafner WRP
Mahr Reservoir
Meadowlark WRF
Rancho Santa FeCalavera PS
Bressi PS
"D" Tank PSPacific Ocean
Encinitas
Batiquitos Lagoon
Buena VistaLagoon Oceanside
Shadowridge WRP
Corintia Meter
OMWDMeter
LakeCalavera
El Camino RealFour SeasonsResort
La Costa Resort
Kemper SportsManagement
Legoland
Aviara ResortAssociation
San Marcos
Vista
Encinitas
Oceanside
X
03
12 01
02
E1
XX
E4
21
17
E5
E6
E2
E8
E7
Legend
Pressure Logger Locations and IDs
Pipelines by Pressure Zone318384550580660Recycled Water FacilitiesPump StationPressure Requlating Station (PRS)
Meter
WRF
Tank
Reservoir
Inactive WRP
Other FreewaysLocal StreetsWater BodyCarlsbad City LimitsSan Diego CountyCarlsbad Municipal Water District Boundary
0 5,000 10,000Feet
Figure 6.2Calibration LocationsRecycled Water Master PlanCarlsbad Municipal Water District
FILENAME: c:\pw_working\projectwise\lwang\d0102644\Figure_6_02-Calibration_Sites.mxdDATE: 5/10/2011
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Table 6.6 SCADA Data Availability
Recycled Water Master Plan Carlsbad Municipal Water District
Facility Name
Upstream Pressure
Zone
Downstream Pressure
Zone Control Details(1)
Encina/Carlsbad PS n/a 384
Pump 1 Closed Twin D Tank > 24-ft
Open Twin D Tank < 20-ft
Pump 2 Closed
Pump 3 Closed Twin D Tank > 18-ft
Open Twin D Tank < 12-ft
Twin D PS 384 550
Pump 1 Closed
Pump 2 Closed
Pump 3 Closed
Pump 4 Closed
Bressi PS 550 660
Pump 1 VSP – Target Pressure = 146 psi
Pump 2 Closed
Pump 3 Open if zone demand > 1,200 gpm
Closed if zone demand < 700 gpm
Calavera PS(2) 384 580
Pump 1 Open
Pump 2 Closed
Pump 3 Closed
Corintia FCV - 550 Open
Faraday PRV 580 384
6-inch 60 psi
10-inch 70 psi
La Costa PRV 550 384
6-inch 102 psi – Set based on SCADA
6-inch 90 psi
8-inch 85 psi
Avenida Encinas PRV 384 318
3-inch 109 psi – Set based on SCADA
8-inch 108 psi
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Table 6.6 SCADA Data Availability (Continued)
Recycled Water Master Plan Carlsbad Municipal Water District
Location
Upstream Pressure
Zone
Downstream Pressure
Zone Control Details
Ralph Valve(3) 550 384 55 psi – Set based on hydraulics.
The Encina Basin Water Reclamation Program, Phase II
Twin D Recycled Water Pump
Station Plans shows that this is a 10-in combination FCV/PSV.
However, CMWD staff indicate it is
operated as an altitude valve.
10-inch
D Tanks 384 384 Initial Level = 10.8 feet, based on SCADA
C Tank 384 384 Initial Level = 13.5 feet, based on SCADA
Mahr Reservoir 550 550 Levels set based on SCADA
upstream pressures for Corintia
Valve and pressure logger in area
Meadowlark Reservoir - 550 HGL set at HWL of 318 feet. A single pump to represent two
pumps. Pump Station Head with
two pumps running 240 feet. Max flow of pump station with two
pumps is 3,250 gpm. Based on
Mahr Reservoir O&M Manual, October 2008
Note: (1) Control details were based on operational control strategy at the time of calibration, October 2009, and are modified based on staff needs.
(2) As of Fall 2011, the Calavera Pump Station target psi was 177 psi, pump start was set for 145 psi, pump stop was set for 190 psi, and second call set for 700 gmp (3) As of Fall 2011, the Ralph Valve is SCADA controlled by both flow total through Corinitia meter and level in
D tanks.
6.3.2 Extended Period Model Calibration
One model scenario was created in the hydraulic computer model for the model calibration.
The scenario was setup as an EPS run for 24 hours with demands based on actual field
tank fluctuations and observed supply into the system. The goal of calibration was to have
the model results within 10 percent or 5 psi of the field observations.
As described previously, the recycled water demands allocated in the model were based on
the average demands obtained from the geocoded billing records of calendar year 2008.
The average 2008 demand without the demands of the La Costa Golf Course demands (fed
by Gafner WRP) and OMWD (fed by Meadowlark WRF) is 2,287 gpm. This demand was
January 2012 6-15 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 6
then scaled by 1.28 to match the total system production of 2,922 gpm recorded for
October 17, 2009. The hourly supply mass balance for this day is presented in Table 6.7.
Table 6.7 Mass Balance for Calibration Day
Recycled Water Master Plan Carlsbad Municipal Water District
Date and Time
of Recordings
Supply from Carlsbad
WRF PS
(gpm)
Supply from Corintia
Valve
(gpm)
Supply from Storage Tanks
C and D
(gpm)
Total Supply (Demand)
Balance
(gpm)
10/17/09 0:00 3,352 3,571 -1,508 8,431
10/17/09 1:00 3,340 4,360 7 7,693
10/17/09 2:00 3,220 4,290 1,142 6,368
10/17/09 3:00 3,216 3,780 1,464 5,533
10/17/09 4:00 3,209 3,940 2,057 5,092
10/17/09 5:00 3,175 3,750 2,596 4,329
10/17/09 6:00 0 3,209 2,704 505
10/17/09 7:00 0 3,372 755 2,617
10/17/09 8:00 0 2,969 1,295 1,674
10/17/09 9:00 0 3,003 1,188 1,816
10/17/09 10:00 0 2,909 1,349 1,560
10/17/09 11:00 0 2,872 1,781 1,091
10/17/09 12:00 0 2,874 1,781 1,093
10/17/09 13:00 0 14 -816 830
10/17/09 14:00 0 22 -923 945
10/17/09 15:00 0 13 -923 936
10/17/09 16:00 0 11 -922 933
10/17/09 17:00 0 9 -976 985
10/17/09 18:00 0 11 -975 986
10/17/09 19:00 0 31 -1,028 1,058
10/17/09 20:00 0 559 -1,027 1,586
10/17/09 21:00 0 854 -1,945 2,799
10/17/09 22:00 3,193 1,247 -2,321 6,761
10/17/09 23:00 3,172 1,600 274 4,498
Average 1,078 2,053 210 2,922
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The diurnal demand curves presented in Figure 6.3 were prepared from the supply mass
balance for the two days for which SCADA data was available. It should be noted that, as
SCADA data was not gathered after 1:00 p.m. for Sunday, October 18, 2009, the data from
Saturday, October 17, 2009 was used for the last six hours of the weekend diurnal demand
curve.
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
Ratio of Hourly Demand to Average Demand for the DayHour of Day
Weekday Diurnal Weekend Diurnal
Figure 6.3 System Wide Diurnal Demand Patterns
The diurnal pattern of October 17, 2009 was then used to develop diurnal curves for
individual pressure zones by adjusting for diurnal patterns that were developed for the two
golf courses that take recycled water during the daytime hours to fill the on-site lakes. The
diurnal curves used in the hydraulic model are smoothed out compared to the raw data
shown in Figure 6.3 as the actual demand variation will vary on a daily basis and simplified
curves are considered more appropriate for planning purposes.
The diurnal curves presented in Figure 6.3 indicate that CMWD’s demands peak at about
11:00 p.m. and begin to drop off in the early morning hours. Demands during the day are
minimal until the evening peak begins after 10:00 p.m. When compared with the typical
diurnal curves presented in Chapter 3, it can be concluded that the majority of CMWD’s
nightly irrigation demands occur during the early night hours, between 10:00 p.m. and
3:00 a.m., and are not evenly distributed across the 8-hour irrigation period.
January 2012 6-17 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 6
Hazen-Williams roughness coefficients (C factors) were assigned. These C factors were
developed from standard published values for pipes of similar material and age and are
presented in Table 6.8.
Table 6.8 Pipeline Roughness Coefficients
Recycled Water Master Plan
Carlsbad Municipal Water District
Class Number Pipe Material(1) Installation Year Age (Years)
Percent of Total (%)
Typical C Factor Range Selected C Factor
1 ACP after 1970 0-35 3 130–150 130
2 CML&C STL after 1970 0-35 15 140–150 130
3 DIP 1985 - 2004 7-26 7 130–150 130
4 PVC All All 75 130–160 130
5 HDPE 2000 - 2004 7-11 <1 120–150 130
Note: (1) ACP: asbestos cement pipe
CML&C STL: cement mortar lined steel DIP: ductile iron pipe
PVC: polyvinyl chloride
The calibration process required that the model simulations duplicate the boundary
conditions observed at the time of each test. Boundary conditions include sources of
supply, storage facilities, and other locations where water flows into or out of the distribution
system. The boundary conditions were set based on SCADA data from the City’s system
during the pressure logger data retrieval.
Where significant differences were revealed between the model results and the field
observations during calibration, the model data was rechecked against known data to
evaluate the accuracy of the data. This could include checking pipe diameters and similar
data. If this data appeared to be correct, additional steps were taken to verify connections
between pipes, verify pressure zone boundaries, and perform similar checks.
Adjustments made to the model during the calibration process included:
• Establishing demand patterns / diurnal curves for users in the upper zone, lower
zone, hydro-pneumatic zones, and the golf courses known to irrigate during the day.
The individual demand patterns / diurnal curves were calculated such that the overall
aggregate weighted demand pattern would match the mass balance calculated for
the calibration period.
• Updating the hydraulic model to incorporate changes to the distribution system for
which CMWD provided drawings.
• Adding hydro-pneumatic tanks to the Calavera PS and Bressi PS to better reflect how
these facilities operate.
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• Changing the Corintia Meter from a flow control valve to a throttle valve.
• Adding minor losses to the Corintia Meter vault and some pipelines to limit the
amount of flow from Mahr and allow more pumped flow from the Carlsbad WRF.
• Revising the assumed OMWD demand pattern based on the levels in Mahr Reservoir
relative to the flow through the Corintia Meter, discussions with OMWD staff, and
evaluation of OMWD’s 2004 Recycled Water Master Plan.
• Alterations of elevations in the vicinity of Whiptail Loop north of Faraday Avenue to
reflect grading changes. During the calibration process, it was determined that
grading for a development had altered the ground elevations reflected in the City’s
contour layer. Elevations were adjusted accordingly to reflect the grading.
The calibration process attempted to correct any errors found in the model data before
calibrating friction coefficients or suggesting that unknown field conditions (such as a closed
main line valve) might exist.
6.3.3 Extended Period Calibration Results
Calibration results were analyzed by comparing the differences between field observed
pressures and model results for each pressure logger, pump station, and reservoir. These
comparisons were made after errors were corrected and adjustments were made in the
model. Charts showing the comparison of model results to field data for each logger and
facility are included in Appendix F. Figure 6.4 presents the comparison of model results to
field data for three storage reservoirs; D Tanks, C Tank, and Mahr Reservoir.
A shown in Figure 6.4, the levels within the reservoirs follow the trending of the field data.
The model results for the pressure loggers, pump stations, and reservoirs are generally
judged to fall within 10 psi of the field data.
6.3.3.1 Summary of Calibration Results
The locations of the remote pressure loggers that were installed in the system to gather
field data are shown on Figure 6.2. The calibration results of these individual pressure
loggers, as well as the tank levels, pump stations, and pressure regulating valves are
presented in Appendix F.
Based on the results presented in Figure 6.4 and in Appendix F, it can be concluded that
the model results closely match field conditions for most calibration points. Hence, the
hydraulic model is therefore considered calibrated and can be used to evaluate the system
hydraulics under existing and future demand conditions, identify deficiencies, and size
facilities to address deficiencies and serve the future customers, while meeting the planning
and evaluation criteria outlined in Chapter 7 of this report.
January 2012 6-19 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 6
0
5
10
15
20
25
30
35
Level (ft)TimeMahr Reservoir -SCADA Twin "D" Tanks -SCADA
"C" Tank -SCADA Mahr Reservoir -Model
Twin "D" Tanks -Model "C" Tank -Model
Figure 6.4 Reservoir Calibration Results
It is important to note that model calibration for any water system is an ongoing effort. As
changes in the system occur from changing demands, new infrastructure development, or
changing operational settings, the model must be periodically updated and checked to
confirm that the model results are in agreement with field measurements. Therefore, this
calibration effort serves as a baseline for future calibration efforts.
6.3.4 Water Quality Calibration
Water quality samples were obtained by CMWD staff on October 14, 2010. Initial model
calibration plans (as outlined in Appendix D) were to calibrate the water quality and
hydraulic components of the model over the same time period. Due to a server outage, the
SCADA data was unavailable and the hydraulic calibration was conducted with data for
October 17, 2009. Hence, the conditions used for the hydraulic model calibration do not
coincide with the day that the water quality samples were taken.
It was necessary to make the assumption that the system operations of the recycled water
distribution system are similar from day to day and that the hydraulic conditions on the day
of water quality sampling (Wednesday October 14, 2009) were sufficiently similar to the day
of hydraulic calibration (Saturday October 17, 2009). It should be noted that water quality
modeling is extremely sensitive to the hydraulic conditions in the distribution system. The
6-20 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 6
results of this water quality calibration should take this into consideration. Table 6.9
presents chlorine residual levels sampled at each of the sampling sites.
Table 6.9 Water Quality Samples
Recycled Water Master Plan Carlsbad Municipal Water District
Sample Location
ID Location Zone Time(1)
Chlorine Residual (Total Chlorine
mg/L)
A Tamarack west of Cay Dr. 580 09:00 0.0
B Transmission Main from C Tank 384 09:25 0.0
C Cannon Rd. northeast of Faraday Av. 384 09:35 0.2
D Faraday Av. and Priestly Dr. 550 09:47 0.2
E Melrose Dr. between Faraday Av. and Priestly Dr. 660 10:00 5.5
F Aviara Py., between Ambrosia Ln. and
Mimosa Dr.
384 10:13 1.1
G Corintia St. west of Melrose Dr. N/A 10:25 3.0
H The Crossings, south of Grand Pacific Dr. and north of Palomar Airport Rd. 384 11:37 2.0
I Transmission Main near D Tank 384 11:09 3.0
J Avenida Encinas and Embarcadero
Ln.
384 11:25 3.9
K Transmission Main from Mahr Reservoir N/A 10:52 4.2
Note:
(1) All water quality samples taken on October 14, 2010.
As seen in Table 6.9, the sampled chlorine residuals ranged from 5.5 mg/L downstream of
Bressi Pump Station to undetectable levels in the north areas of CMWD. The locations and
levels of each of the sampled residuals are shown on Figure 6.5. Note that Sample E
exceeds the sampled chlorine residual at either source (Carlsbad WRF and Meadowlark
WRF), suggesting that the chlorine residual at the sources must have been fluctuating to
higher levels prior to sampling (all samples were taken within a few hours).
At Carlsbad WRF, the average chlorine residual between September 15 and September 30,
2009 was 9.1 mg/L. For Meadowlark WRF, the average minimum chlorine residual during
August 2009 was 16.3 mg/L. However, discussions with City staff have indicated that
chlorine residual is reduced to limit the chlorine residual to less than 10 mg/L. At the time of
calibration, Meadowlark WRF staff reduced the chlorine residual considerably, but without
evaluating the resulting chlorine residual on a continuous basis. The modeled initial source
chlorine residual was therefore adjusted iteratively to match the sampled chlorine residual
of 3.0 mg/L at the location of Site G. After this iterative process, a chlorine residual of
4.5 mg/L was used at Meadowlark.
"C" Tank
Carlsbad WRF
Gafner WRP
Mahr Reservoir
Meadowlark WRF
Agua HediondaLagoon
Twin "D" Tanks
C
a
min
o
R
e
alElm A veMarron Rd
Carlsbad Blvd
Hig
hla
n
d D
r
A londra W ayPaseo NorteCollege BlvdPalomar Airport
Aviara Pkwy El Fuerte StCosta AvePoinsettia LnTam arack A veCannon Rd
Calle BarcelonaRanc ho Santa FeCalavera PS
Bressi PS
"D" Tank PSPacific Ocean
Encinitas
Batiquitos Lagoon
Buena VistaLagoon Oceanside
Shadowridge WRP
OMWDMeter
Corintia Meter
LakeCalavera
Four SeasonsResort
La Costa Resort
Kemper SportsManagement
Legoland
Aviara ResortAssociation
San Marcos
Vista
Encinitas
Oceanside
I1.03.0
H0.32.0
A0.00.0
J3.83.9 F0.31.1
E1.55.5
D2.40.2
B0.00.0
K3.04.2
C0.10.2
0 5,000 10,000Feet
Figure 6.5Water Quality Calibration ResultsRecycled Water Master PlanCarlsbad Municipal Water DistrictFILENAME: c:\pw_working\projectwise\lwang\d0102644\Figure_6_05-Water Qualityy_Calibration_Results.mxdDATE: 5/10/2011Pipelines by Pressure Zone
318
384
550
580
660
Recycled Water Facilities
Pump Station
Pressure Requlating Station (PRS)
Meter
WRF
Tank
Reservoir
Inactive WRP
Other
Freeways
Private Pipeline
Local Streets
Carlsbad City Limits
San Diego County
Carlsbad Municipal Water District Boundary
Poor
Legend
Fair
Good
Calibration Correlation
Residual Sampling Sites
ID
Sample ResidualModel ResidualA#.##.#
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While some chlorine decay information can be calculated based on the sample times and
locations, detailed hydraulic information on transients within the distribution system is not
available. A chlorine jar test would allow estimation of the decay coefficient by removing
hydraulic variation within the system. However, a chlorine jar test data was not available. In
absence of chlorine jar test data, a global bulk chlorine decay coefficient of -0.05 along with
a default global wall chlorine decay coefficient of -0.15 were used.
6.3.5 Water Quality Calibration Results
Table 6.10 presents model predictions of water quality chlorine residual samples. For each
model prediction, the correlation of the model predictions to the sampled chlorine residuals
is noted with a qualitative statement. Good means that the model prediction and sampled
chlorine residual varied by less than 10 percent. Fair means that the model prediction and
sampled results varied between 10 and 50 percent. Poor means that the difference
between model prediction and sampled results was greater than 50 percent.
Table 6.10 Water Quality Calibration Results
Recycled Water Master Plan
Carlsbad Municipal Water District
Sample Location
ID
Pressure
Zone
Sampled Chlorine Residual (Total Chlorine
mg/L)
Model Predicted(1) Chlorine Residual
(Total Chlorine mg/L)
Correlation of Model Prediction to
Samples(2)
A 580 0.0 0.0 Good
B 384 0.0 0.0 Good
C 384 0.2 0.1 Fair
D 550 0.2 2.4 Poor
E 660 5.5 1.5 Good
F 384 1.1 0.3 Good
G N/A 3.0 3.9 Fair
H 384 2.0 0.3 Poor
I 384 3.0 1.0 Poor
J 384 3.9 3.8 Good
K N/A 4.2 3.0 Fair
Notes:
1) All water quality samples taken on October 14, 2010. The hydraulic model EPS calibration was conducted for October 17, 2010. Hydraulic conditions of October 17, 2010 were used for this analysis. It should be noted that water quality modeling can be extremely sensitive to the hydraulic conditions in the distribution
system and the results of this water quality calibration should take this into consideration.
2) Good = Chlorine residual variance < 10 percent; Fair = 10-50 percent; and Poor = greater than 50 percent.
6-24 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 6
As shown in Table 6.10, model predictions for chlorine residual deviated significantly from
the sampled chlorine residuals. The most significant deviations were in the upper pressure
zones of the distribution system. Average chlorine residuals for the entire distribution
system are shown by pipeline segment on Figure 6.5.
The water quality component of the model was not further calibrated. CMWD initially
planned to repeat the water quality sampling. However, with the primary purpose of the
model being the sizing of future pipelines, it was decided that the hydraulics of the model
were accurate enough for system analysis and planning.
6.4 FUTURE SYSTEM MODEL CREATION
The future system hydraulic model was created to evaluate and size expansion alignments,
pump station improvements, and storage recommendations discussed in Chapter 9.
Development of the future system model consisted of the following steps:
• Determine preliminary alignments of expansion segments based on locations of the
potential customers from the customer database
• Import preliminary expansion segments into the hydraulic model
• Assign demands from the customer database to the expansion segments (excluding
customers too far away to be included in expansion segments, adding demands for
vacant land, and remove demands from ultimate system for temporary agricultural
demands)
• Increase capacity of recycled water sources, pump stations, and storage based on
preliminary analysis in Chapter 9
• Increase sizing of pipelines to resolve deficiencies in the proposed system
The future system model was created based on expansion laterals to reach as many
customers as possible with minimal new pipeline length. The specific alignments will be
discussed in Chapter 9. Customer laterals are drawn to the customer database node within
the model. However, as will be discussed in more detail in Chapters 9 and 10, costs for the
customer laterals are developed based on the number of retrofit customers rather than
actual pipeline length. Thus, the lengths of the customer laterals are not included in
development of the expansion segment lengths.
A pipeline set was created to account for the potential decrease in friction factors as
pipelines in the distribution system age. As outlined in Chapter 7, a Hazen-Williams
roughness coefficient of 120 was used for pipelines over 20 years of age. For the future
system, all existing pipelines were assumed to be greater than 20 years of age by this time.
Where pipeline alignments fell within the City’s boundary, junction elevations were
interpolated from the elevation contours provided by CMWD. For pipeline alignments
outside the coverage of the elevation contours provided by CMWD, approximate elevations
were calculated from data obtained from USGS (USGS, 2010).
January 2012 7-1 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 7
Chapter 7
PLANNING AND EVALUATION CRITERIA
7.1 INTRODUCTION
This chapter presents the planning and evaluation criteria that were used to identify system
deficiencies in the Carlsbad Municipal Water District’s (CMWD) existing system and to size
system expansions. The planning and evaluation criteria discussed in this chapter include
system pressures, pipelines, storage reservoirs, and booster pumping stations. The criteria
discussed herein are also summarized at the end of this chapter in Table 7.1.
7.2 SYSTEM PRESSURES
The recycled water system pressure is ideally designed to be slightly lower than the potable
water system pressure. This pressure differential reduces the risk of potable water
contamination from recycled water, in the event that an adjacent recycled water main
breaks. However, this requirement often cannot be met due to the following two reasons:
1. System pressures in water systems vary and pressure zone boundaries of potable
and recycled water systems typically do not overlap.
2. It is preferred to maintain a minimum pressure in the recycled water system of
approximately 60 pounds per square inch (psi) to meet the operating requirements for
most sprinkler systems. However, the minimum pressure in potable water systems is
typically 40 psi.
As the chance of cross contamination is minimal due to disinfection and a minimum
horizontal separation of 10 feet between potable and recycled water pipelines, it is
assumed that the layout of the recycled water system expansions does not need to be
coordinated with the existing potable water system pressure ranges.
The minimum system pressure used for pipeline sizing in this RWMP is 60 psi under peak
hour demand (PHD) conditions.
While the maximum system pressure under minimum day demand (MinDD) conditions is
limited to 80 psi by the California Plumbing Code (CPC, 2007 – Section 608.2), CMWD
does not anticipate dual plumbing, or other uses which would include piping inside a
building. Thus, 125 psi will be used as the maximum pressure criteria, above which a
pressure regulator will be considered at the meter connections. In locations with pressures
exceeding 150 psi, the pipeline class used for construction of the pipeline segments should
be considered.
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7.3 PIPELINE VELOCITIES AND HEAD LOSS
The maximum velocity in pipelines should not exceed 7 feet per second (ft/s) under PHD
conditions in all existing pipelines, regardless of diameter.
Proposed distribution pipelines, those 12 inches and less in diameter, will be sized such
that the maximum velocity should not exceed 7 ft/s under PHD conditions. Proposed
transmission mains, those greater than 12 inches in diameter, will be sized such that the
maximum velocity should not exceed 5 ft/s under PHD conditions. A lower pipeline velocity
is used for transmission mains to avoid excessive sloping of the hydraulic grade line across
pressure zones.
For existing pipelines, the maximum head loss should not exceed 7 feet per thousand feet
(ft/1,000 ft) under PHD conditions with the entire distribution network in service. Proposed
pipelines will be sized so that the maximum head loss should not exceed 5 ft/1,000 ft.
As discussed in Chapter 6, the hydraulic model uses the Hazen-Williams hydraulic
calculation to calculate head loss. A Hazen-Williams roughness coefficient of 120 is used
for pipelines greater than 20 years in age, and a roughness coefficient of 130 is used for
pipelines less than 20 years in age.
Most of CMWD’s pipelines are relatively new and constructed of PVC material, for which a
roughness coefficient of 140 is typically used in design of pipelines. The roughness
coefficients used in this planning study are lower than that used in design of pipelines to
account for potential biogrowth associated with recycled water systems with lower chlorine
residuals, minor losses, which are not accounted for individually in this level of planning
study, and other potential unknown conditions.
7.4 PIPELINE SIZING CRITERIA
Pipeline sizing is based on several factors including:
• Demand conditions
• Pipeline velocity
• Pipeline head loss
Pipelines are selected so that they do not exceed velocity and head loss criteria under PHD
conditions. When a pipeline exceeds the velocity or head loss criteria during PHD, it is
upsized to the next standard size. Velocity criteria are discussed above.
The minimum pipeline size of new distribution pipelines, excluding service laterals, is
4 inches in diameter, which is used for dead-end pipelines less than 1,000 feet in length.
CMWD uses 6-inch pipelines for non-looped, dead-end pipelines greater than 1,000 feet in
length and 8-inch diameter pipelines for looped pipelines.
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The standard sizes used for pipelines include 4-inch, 6-inch, 8-inch, 12-inch, 16-inch,
20-inch, 24-inch, 30-inch, and 36-inch diameter pipelines.
7.5 STORAGE SIZING CRITERIA
To operate a recycled water system with reservoirs that are supplied from the water
reclamation facilities, two types of storage are required and an additional type of storage is
used within CMWD’s system. These are:
1. Operational Storage. The storage required to buffer demand fluctuations under
maximum day demand (MDD) conditions. The volume required for this storage
component is dependent upon the hourly variation of the customer’s demand and the
variation of flow from the various water reclamation facilities.
2. Short-term Emergency Storage. The storage volume required to protect reservoirs
from complete drainage. Emergency storage provides a few hours to respond to an
emergency and make operational adjustments without immediate interruption of
service.
3. Seasonal Storage. The storage volume used to buffer seasonal peak flows, allowing
the system to supply customer demands in excess of the maximum daily supply
capacity of CMWD’s supply sources. Seasonal storage allows recycled water to be
stored during periods of low demands, such as winter months, to be used during
periods of high demands, such as summer months. Note that seasonal storage
functions as a supply, and thus criteria for sizing seasonal storage are not applicable
unless seasonal storage was sized to meet a specific supply requirement. Seasonal
storage is discussed in more detail in Chapter 4.
7.5.1 Operational Storage
Operational storage is calculated based on the estimated recycled water demand of the
existing customers and their associated diurnal patterns. Figure 7.1 presents an analysis
based on CMWD’s system diurnal curve on October 16 and 17, 2009. The average system
demand in this 24-hour period was 4.9 mgd, which equates to an average demand of
3,413 gpm. Assuming demands in excess of the average demand for the day should be
provided by operational storage, the area above the average demand line represents the
amount of demand that must be provided from storage. This area represents approximately
1.7 million gallons (MG), which is about 33 percent of the average demand over the course
of a day (1.7 MG / 4.9 mgd).
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0
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
9,000
10,000
7:00 PM 8:00 PM 9:00 PM 10:00 PM 11:00 PM 12:00 AM 1:00 AM 2:00 AM 3:00 AM 4:00 AM 5:00 AM 6:00 AM 7:00 AM 8:00 AM 9:00 AM 10:00 AM 11:00 AM 12:00 PM 1:00 PM 2:00 PM 3:00 PM 4:00 PM 5:00 PM 6:00 PMFlow (gpm)Time of Day
Demand Met by Supply Required Storage Volume Ave Demand Demand
Required
Storage
Volume
1.7 MG(33%)
Figure 7.1 Operational Storage Requirement
CMWD’s operational storage is currently provided at various locations in the recycled water
distribution system and includes the following:
• C Tank
• Twin D Tanks
• Mahr Reservoir
In addition, supply from the treatment facilities is buffered by equalization basins consisting
of:
• Mahr Reservoir
• Equalization basin at Carlsbad WRF
Note that Mahr Reservoir is included in both categories, as CMWD does use Mahr
Reservoir for daily peaking of the 550 zone. For the purposes of this study, the supply
equalization basin at Carlsbad WRF was not counted as operational storage. But
functionally, CMWD can use this facility if necessary.
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7.5.2 Short-term Emergency Storage
Short-term Emergency Storage is required to provide operational flexibility during
emergencies, such as a temporary shutdown of any of the WRPs or pump stations. Based
on an emergency response time of 4 hours, the capacity of all reservoirs should include an
additional 17 percent of MDD (4 hrs / 24 hrs = 17% of MDD, which is equivalent to
80 minutes of PHD) to provide buffer capacity for emergency needs.
7.5.3 Seasonal Storage
Seasonal storage is treated as a source of supply and is discussed in more detail in
Chapter 4.
7.5.4 Summary
In summary, the operational and emergency storage requirements are 33 percent of MDD
and 17 percent of MDD, respectively. For planning purposes, it is therefore recommended
that CMWD have a total of 50 percent (33% + 17%) of MDD available for storage.
7.6 PUMP STATION SIZING CRITERIA
Two different pump station (PS) sizing criteria were used for the system analysis in this
study. The criterion that should be applied for the sizing of a PS is dependent upon the
location of reservoir storage in the zone that the PS pumps into. The two criteria are:
• Pressure zones with gravity reservoir storage. These zones have the benefit that
reservoirs provide additional supply during the peak hours of MDD (reservoir
drainage) and provide buffer capacity during the minimum hours of MDD (reservoir
filling). This allows pump station sizing for the average hour demand of MDD. Hence,
all pump stations that pump into a zone with gravity storage are sized for MDD.
• Pressure zones without gravity reservoir storage. These zones do not provide the
benefit of additional supply from reservoirs during the peak hours of MDD. Hence, all
pump stations that pump into a zone without gravity storage (closed system) need to
be sized for PHD with a standby pump unit.
The total pumping capacity of a PS needs to be sufficient to serve the required demand
with the largest pump unit out of service, so that one pump unit can be designated as a
spare to accommodate repairs and maintenance activities without interruption of system
operations. However, this criterion was not applied to the Carlsbad WRF PS, rated at
10,000 gpm, as CMWD has incorporated storage in the pressure zone into which the
Carlsbad WRF PS pumps.
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7.7 SYSTEM RELIABILITY CRITERIA
System reliability criteria are intended to evaluate a recycled water system’s ability to meet
recycled water demands during events such as power outages. While less critical than in a
potable water system, extended outages could result in costly loss of property, as irrigation
may not be available for customer’s landscaping, especially in the cases of customers such
as golf courses, where the landscaping represents an extensive investment. As CMWD
begins to connect users of different usage classes, such as industrial, dual plumbing, or fire
water usage types, system reliability will be even more important.
CMWD’s customers are required to maintain separation of the recycled water and potable
water systems. Hence, CMWD’s customers do not have potable water backup supplies with
the exception of the golf courses that blend recycled water and potable water in their lakes
using an air gap for the potable water supply to avoid cross connections.
In case of a power outage, the majority of CMWD’s recycled water customers can be
served from gravity storage and through PRV stations. The emergency storage capacity
discussed in Section 7.5 provides 4 hours of supply under MDD conditions to make
operational adjustments, such as the installation of a portable backup power generator.
7.8 SUMMARY PLANNING AND EVALUATION CRITERIA
The evaluation and sizing criteria described in this chapter are summarized in Table 7.1.
Table 7.1 System Evaluation Criteria
Recycled Water Master Plan
City of Carlsbad
Parameter Evaluation Criteria Demand Condition
System Pressure
Minimum System Pressure 60 psi Peak Hour Demand
Maximum System Pressure(1) 125 psi Minimum Hour Demand
Maximum System Pressure(2) 150 psi Minimum Hour Demand
Pipeline Velocity
Evaluation of Existing Pipelines:
Max. Velocity 7 ft/s Peak Hour Demand
Sizing of New Pipelines:
Max. Velocity (Diameter > 12-inch) 5 ft/s Peak Hour Demand
Max. Velocity (Diameter ≤ 12-inch) 7 ft/s Peak Hour Demand
Pipeline Head Loss
Evaluation of existing pipelines:
Max. Head Loss 7 ft/1,000 ft Peak Hour Demand
Sizing of new pipelines:
Max. Head Loss 5 ft/1,000 ft Peak Hour Demand
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Table 7.1 System Evaluation Criteria
Recycled Water Master Plan
City of Carlsbad
Friction Factor (Hazen-Williams)
Existing Pipelines (< 20 years old) 130 All conditions
Pipelines (20-50 years old) 120 All conditions
Storage Volume
Operational Storage 33% of MDD(3) Maximum Month Demand
Short-term Emergency Storage 17% of MDD(4) Maximum Month Demand
Total Storage 50% of MDD(2) Maximum Month Demand
Pump Station Standby Capacity
For Zones with Gravity Storage Meet MDD with largest
pump unit OOS(5) Maximum Month Demand
For Zones without Gravity Storage Meet PHD with largest
pump unit OOS(5)
Peak Hour Demand
Backup Power Connection for Portable Generator
(in Zones without
Gravity Storage)
Peak Hour Demand
Notes:
(1) Maximum pressure without pressure reducing valves; higher pressures are acceptable if pressure reducing valves are installed at the meter connection (CPC, 2007). (2) Maximum pressure for standard pipelines. For areas with higher pressures, the pipeline class (pressure
rating) should be considered. (3) Based on the City’s diurnal pattern on October 16 - 17, 2009. (4) Based on an emergency response time of 4 hours (4 hours divided by 24 hours). (5) OOS = out of service
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Chapter 8
EXISTING SYSTEM EVALUATION
This chapter evaluates the existing system to identify system constraints and inefficiencies
that should be resolved for optimal system operation and preparation for future system
expansion. This chapter consists of the following five sections:
• Hydraulic Analysis
• Storage Analysis
• Pump Analysis
• Energy Analysis
• Water Quality Analysis
Where appropriate, recommendations are made for addressing system deficiencies or
improving system performance. Capital cost estimates are provided for each
recommendation. The chapter concludes with a summary of system inspection
requirements. A detailed description of the existing system is included in Chapter 2.
8.1 HYDRAULIC ANALYSIS
A hydraulic analysis was performed on the existing system for Minimum Day Demands
(MinDD), Average Annual Demands (AAD), and Maximum Month Demands (MMD). Diurnal
curves that included peak hour demand were used to account for the variation of demand
throughout the day for the MinDD, AAD, and MMD scenarios. System analysis criteria are
discussed in Chapter 7 and are summarized in Table 8.1.
Figure 8.1 shows locations with pressures exceeding 125 psi. Figure 8.2 shows locations
with low pressures below 60 psi and pipes with velocities and head losses exceeding the
stated criteria in Table 8.1.
8.1.1 Distribution System
Using the hydraulic model, the distribution system was evaluated under MinMD, AAD, and
MMD demand conditions. The model predicted both high and low pressure deficiencies
under the evaluated conditions.
8-2 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 8.doc
Table 8.1 System Evaluation Criteria
Recycled Water Master Plan Carlsbad Municipal Water District
Parameter Evaluation Criteria Demand Condition
System Pressure
Minimum System Pressure 60 psi Peak Hour Demand
Maximum System Pressure(1) 125 psi Minimum Hour Demand
Maximum System Pressure(2) 150 psi Minimum Hour Demand
Pipeline Velocity
Evaluation of Existing Pipelines:
Max. Velocity 7 ft/s Peak Hour Demand
Sizing of New Pipelines:
Max. Velocity (Diameter > 12-inch) 5 ft/s Peak Hour Demand
Max. Velocity (Diameter ≤ 12-inch) 7 ft/s Peak Hour Demand
Pipeline Head Loss
Evaluation of existing pipelines:
Max. Head Loss 7 ft/1,000 ft Peak Hour Demand
Sizing of new pipelines:
Max. Head Loss 5 ft/1,000 ft Peak Hour Demand
Notes: (1) Maximum pressure without pressure reducing valves; higher pressures are acceptable if pressure
reducing valves are installed at the meter connection (CPC, 2007). (2) Maximum pressure for standard pipelines. For areas with higher pressures, the pipeline class (pressure
rating) should be considered.
Areas exceeding the 125 psi criteria are shown in Figure 8.1 by maximum pressure. As
shown in the evaluation criteria in Table 8.1, the maximum pressure was evaluated under
MinMD conditions and consisted of two criteria, a 125 psi maximum above which service
lateral pressure regulating devices should be considered and a 150 psi maximum above
which consideration should be made for higher pipeline pressure classifications during
design. Note that junctions that are a part of facilities (e.g., discharge headers for pump
stations) were excluded from this analysis and are not shown as deficient.
Approximately 35 percent (by demand) of the system exceeds the maximum pressure
criteria of 125 psi. Approximately 7 percent (by demand) of the system exceeds the second
maximum pressure criteria of 150 psi, and the associated pipelines should be designed
accordingly for higher pressures.
Low-pressure deficiencies were also identified. Areas with pressures below 60 psi are
shown on Figure 8.2. The majority of the low pressure deficiencies are not located near
pipelines with velocity or head loss deficiencies, indicating that low pressures in the system
are predominantly due to higher elevations within the existing pressure zones, rather than
localized head loss due to pipeline velocities during periods of high demand.
"C" Tank
Carlsbad WRF
Gafner WRP
Mahr Reservoir
Meadowlark WRF
Agua HediondaLagoon
Twin "D" Tanks
Calavera PS
"D" Tank PS
Pacific Ocean
Encinitas
Batiquitos Lagoon
Buena VistaLagoon Oceanside
Faraday PRS
Avenida Encinas PRS
La Costa PRS
Corintia Meter
OMWDMeter
LakeCalavera
EL CAMINO REALCANNON R D
POINSETTIA L NCOLLEGE B L
PALOMAR A I R P O R T R D
A L G A R D
C
A
R
L
S
B
A
D BL
A
VI
ARA
P
Y
MELR
O
S
E D
R
L A COSTA AV
RANCHO SANTA FE RDOLIVENHAIN R D
CA
M
I
NO JUNIPERO
Legend
Nodes with High Pressures125 - 150 psi151 - 175 psi
176 - 200 psiFacilities
Meter
Pump StationPressure Regulating Station
WRF
Tank
Reservoir
Recycled Water PipelinesDiameterLess than 6"
6" to 8"10" to 14"
16" and largerOtherFreeways
Major RoadsLocal Streets
Carlsbad Municipal Water District Boundary
Water Body
Carlsbad City Limits
San Diego County
0 5,000 10,000Feet
Figure 8.1Pressures Greater than 125 psi Carlsbad Municipal Water District
FILENAME: c:\pw_working\projectwise\lwang\d0102644\Figure_8_01 Pressure Exceeding 125 psi VerB.mxdDATE: 5/11/2011
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This page intentionally left blank.
"C" Tank
Carlsbad WRF
Gafner WRP
Mahr Reservoir
Meadowlark WRF
Agua HediondaLagoon
Twin "D" Tanks
Calavera PS
Bressi PS
"D" Tank PS
Pacific Ocean
Encinitas
Batiquitos Lagoon
Buena VistaLagoon Oceanside
Faraday PRS
Avenida Encinas PRS La Costa PRS
Meadowlark PS
The Crossings
Corintia Meter
OMWDMeter
D
C
E
LakeCalavera
Park HyattAviara Resort
La Costa Resort
BA
Legoland
Aviara ResortAssociationEL CAMINO REALCANNON RD
POINSETTIA L N
CO L LEGE BLPALOM A R A IR P O R T RD
A L G A R D
C
A
R
L
S
B
A
D B
L
AVIA
RA
PYMELR
O
S
E D
R
LA COSTA AV
RANCHO SANTA FE RDOLIVENHAIN R D
CA
M
I
NO JUNIPERO
Under AAD, MMD
Under MMDModel Nodes with Low PressuresUnder AAD, MMD, and MinMDUnder AAD, and MMDUnder MMDRecycled Water Pipelines (by Diameter)Less than 6"6" to 8"10" to 14"16" and largerWater System Facility
Meter
Pump Station (PS)Pressure Regulating Station (PRS)
WRF/WRP
Tank
Reservoir
Other FreewaysLocal StreetsWater Body
Carlsbad City LimitsSan Diego CountyCarlsbad Municipal Water District Boundary
0 5,000 10,000Feet
Figure 8.2Low Pressure and High VelocitiesRecycled Water Master PlanCarlsbad Municipal Water District
FILENAME: c:\pw_working\projectwise\lwang\d0102644\Figure_8_02-Low_Pressure_and_High_Velocities.mxdDATE: 5/12/2011Legend
Model Pipes with High Velocities / High Headloss
Under AAD, MMD
Under MMD
"D" Tank PS
Four Seasons PT12''
12''14''
6''12"18"18"4"
Four SeasonsResort
A
Aviara ResortAssociation
BPOINSETTIA LNBLACK RAIL RDDOCENA
CAM DE LAS ONDASMALLEEAVIARA PY
KESTREL DR8''
12''
10''
1
4
''24''8''
2 4 ''6''
8''24''
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The hydraulic model predicted head loss and velocity deficiencies at a total of 16 locations,
which are shown in Figure 8.2. In addition, head loss or velocity were predicted to exceed
criteria in pipelines at two locations which are a part of facilities. These pipeline segments
were identified at the Calavera Pump Station hydropneumatic tank and the discharge
pipeline from Meadowlark WRF. Since high head loss could be expected at each of these
locations, these segments were excluded from analysis.
Head loss and velocity deficiencies in 11 locations were along pipelines serving only one
customer. These deficiencies were evaluated on a case-by-case basis. It was determined
that the model predicted that pressure was reduced below the minimum pressure criteria of
60 psi at the point of connection at only one location, the Park Hyatt Aviara Resort.
Pressure at the meter was predicted to fall to 42 psi under AAD conditions and 29 psi under
MMD conditions. It should be noted that the assumed diurnal pattern for the Park Hyatt
Aviara Resort may be different during MMD conditions, with irrigation taking place over a
longer portion of the day. Since this is one of CMWD’s largest and most long-term users, it
is likely that any problems with low pressure would have already been brought to CMWD’s
attention. However, recommendations for two of the deficiencies discussed below are
anticipated to improve the pressure at this location.
Three locations of high head loss, indicated as C, D, and E on Figure 8.2, were located away
from areas of low pressure and are assumed to have limited impact on the system and not
recommended for replacement at this time. However, if one of these pipes should require
replacement due to normal maintenance, then the new pipe should be of a larger diameter.
The locations of the remaining two deficiencies are along Aviara Parkway. These two
deficiencies are listed in Table 8.2 and identified on Figure 8.2 by the corresponding
Map IDs A and B.
Table 8.2 Pipeline Deficiency Locations
Recycled Water Master Plan Carlsbad Municipal Water District
Map
ID Street From To Zone
Exist Diam.
(in)
Repl. Diam.
(in)
Length
(ft)
Low Pressure
Nearby
A Aviara
Pkwy
300' s/o
Poinsettia Ln
Kestrel Dr 384 6 12 1,100 Y
B Aviara Pkwy 300' nw/o Black Rail Ct Four Seasons Pt 384 12 16 1,100 Y
As shown in Table 8.2, a total of 2,200 feet of pipeline along Aviara Parkway is predicted, at
least in part, to cause pressure losses in the area. While velocity in these stretches of
pipeline reach a maximum of 6.3 ft/s under peak hour demand (PHD) conditions, head loss
reaches 13 feet per thousand feet, with total head loss over the deficient pipeline segments
of 25 feet (10.8 psi). It should be noted that, according to the City’s GIS pipeline layer, the
8-8 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 8.doc
diameters in the entire 4,200-foot stretch of pipeline along Aviara Parkway from Poinsettia
Lane to Four Seasons Point range in diameter from 6 inches to 14 inches, transitioning in
diameter four times over this stretch before connecting to the 14-inch pipeline extending
east from Four Seasons Parkway. Note that much of this stretch was constructed in 1989.
A pressure drop of 10 psi under PHD conditions is not significant enough to warrant
replacing the pipeline segment. If CMWD experiences low-pressure problems in the system
in this area under high demand conditions, especially as demands increase as the system
is expanded, replacement of this section may assist in resolving low-pressure problems.
Also, if one of these pipeline segments should require replacement due to normal
maintenance, then the new pipe should be of a larger diameter.
The deficiencies identified in Table 8.2 are shown in Table 8.3 along with the pipeline
segments, which have less significant effects on the system. Model predictions under AAD
conditions are also presented for reference.
Table 8.3 Pipeline Deficiencies Under Demand Conditions
Recycled Water Master Plan Carlsbad Municipal Water District
Map ID Zone Length (ft) Demand Condition
Maximum Head Loss Max
Velocity (ft/s)
Exist
Diam (in)
Par.(1)
Diam (in)
Repl.(2)
Diam (in) (ft/kft) (ft)
A 384 1,100 AAD 5.9 6.3 2.9
1,100 MMD 12.6 13.5 4.4 6 8 12
B 384 1,100 AAD 6.4 5.4 4.7
MMD 11.2 10.9 6.3 12 8 16
C 384 1,300 AAD 8.6 9.5 3.9
MMD 10.5 11.8 4.4 8 8 12
D 384 500 AAD 3.2 1.4 2.5
MMD 8.9 4.1 4.3 8 8 12
E 660 2,200 AAD 2.7 5.2 2.3
MMD 8.1 15.4 4.1 8 8 12
Notes: (1) Parallel
(2) Replacement
As previously mentioned, since pipeline deficiencies C, D, and E are not located near
pressure deficiencies, it is not recommended to replace these pipeline segments. Pipelines
A and B contribute, in part, to low pressures in the area. However, the level of head loss
associated with pipelines A and B does not warrant replacement at this time.
Recommended diameters for any potential replacement or paralleling of pipelines are
included in Table 8.3.
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8.2 STORAGE CAPACITY ANALYSIS
The storage analysis evaluates if CMWD’s existing storage capacity meets the evaluation
criteria for operational and emergency as described in Chapter 7. A definition for each
category of storage criteria is summarized below.
• Operational Storage: The storage required to buffer demand fluctuations under
maximum day demand (MDD) conditions. The required operational storage is defined
as 33-percent of MDD.
• Short-term Emergency Storage: The storage volume required to prevent a reservoir
from completely draining during an emergency situation such as a temporary supply
outage or a demand spike. The required emergency storage is defined as 17 percent
of MDD.
For this analysis, it is assumed that MDD conditions will be similar to MMD conditions.
The existing system storage facilities are summarized in Table 8.4. Storage for Zones 580
and 318 are provided by reservoir capacity in Zone 384, and storage for Zone 660 and 550
is provided by Mahr Reservoir. It should be noted that the Calavera hydro-pneumatic tank
and Bressi hydro-pneumatic tank are not listed in this table, as they are not intended to
provide storage. As will be discussed in Section 8.3, Zones 580 and 660 will not have
storage if power is not available at the Bressi and Calavera Pump Stations.
Table 8.4 Summary of Storage Facilities by Pressure Zone Recycled Water Master Plan
Carlsbad Municipal Water District
Reservoir Zone Volume (MG)
Twin D Tanks 384 2.5
C Tank 384 1.0
Mahr Reservoir 550 32.0(1)
Total Storage 35.5
Note:
(1) CMWD is only allotted 32 MG of the 50 MG capacity of the Mahr Reservoir. The remaining capacity is allocated to the Olivenhain Municipal Water District.
As shown in Table 8.4, CMWD has a total of 35.5 MG of storage. 32 MG of this is
associated with Mahr Reservoir, located in Vallecitos Water District’s (VWD) service area.
While Mahr Reservoir is used to provide operational and short-term emergency storage for
CMWD’s system, CMWD does not typically replenish the reservoir with recycled water from
Carlsbad WRF, and Meadowlark WRF is therefore the only source of replenishment for the
reservoir.
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At this time, daily demands in Zone 550 and 660 are much less than the daily supply from
Meadowlark WRF, so CMWD has some flexibility in its use of Mahr Reservoir for
operational and short-term emergency storage. As demands increase in Zones 550 and
660, CMWD will be limited in its use of Mahr Reservoir as storage unless CMWD
replenishes the reservoir from Carlsbad WRF. Operational and short-term emergency
storage requirements that were calculated based on the evaluation criteria discussed above
are presented in Table 8.5. This table also shows a comparison of these requirements with
the existing storage capacity. It should be noted that storage analysis is not conducted for
Gafner WRP since operational storage is provided by the La Costa Golf Course through on-
site ponds.
Table 8.5 Storage Capacity Evaluation Recycled Water Master Plan
Carlsbad Municipal Water District
Zone
MMD
(mgd)
Required Operational
Storage(1,2)
(MG)
Required
Short-Term Emergency
Storage(1,3)
(MG)
Total Required
Storage
(MG)
Existing
Storage
(MG)
Balance
(MG)
660 0.48 0.16 0.08 0.24 0.0(4) -0.24
550 1.06 0.35 0.18 0.53 0.0(4) -0.53
Subtotal 0.51 0.26 0.77 0.0 -0.77
Subtotal w/ Mahr 0.51 0.26 0.77 32.0(4) +31.2
580 0.35 0.12 0.06 0.18 0.0 -0.18
384 3.61 1.19 0.61 1.80 3.5 +1.70
318 0.06 0.02 0.01 0.03 0.0 -0.03
Subtotal 1.23 0.68 2.01 3.5 1.49
Total w/o Mahr 5.56 1.84 0.94 2.78 3.5 +1.49
Total w/ Mahr 5.56 1.84 0.94 2.78 3.5 +32.69
Notes:
(1) Operational and Emergency Storage requirements are based on the evaluation criteria from Chapter 7. (2) Based on the evaluation criteria, Operational Storage is 33 percent of the MMD. (3) Based on the evaluation criteria, Emergency Storage is 17 percent of the MMD, or four hours.
(4) Supplies from Meadowlark WRF are taken at a constant rate greater than the demand of Zones 550 and 660. Consequently, Operational Storage for Zone 550 is not needed. When necessary, Mahr Reservoir can be used to buffer supplies at Meadowlark WRF.
As shown in Table 8.5, there is enough storage to meet operational and short-term
emergency demand requirements under existing conditions. In addition, the following
conclusions can be made by subarea:
• Since supplies from Meadowlark WRF are taken at a constant rate and are greater
than the demand of Zones 550 and 660, operational storage is not considered
necessary within Zone 550. When necessary, Mahr Reservoir can be used to buffer
supplies at Meadowlark WRF.
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• For Zones 384, 580, and 318, which share common reservoir capacity, the total
required operational and emergency storage is 2.01 MG. For Zones 550 and 660, the
total required operational and emergency storage is 0.77 MG.
8.3 PUMP STATION CAPACITY ANALYSIS
The pump analysis evaluated the adequacy of the existing system pump station capacities.
CMWD’s existing recycled water system consists of five pressure zones and associated
booster pumping stations. The suction and discharge zones and flow capacities for each
pump station are listed in Table 8.6. This table lists both the total capacity for each pump
station and the firm capacity, which is the capacity with the largest unit out of service. Note
that each of CMWD’s booster pumping stations include a standby pump and consist of
pumping units of uniform sizing, so the design capacity is equivalent to the firm capacity. As
discussed in Chapter 7, the criteria for each pump station is to meet the PHD with the
largest unit out of service.
Table 8.6 Booster Pump Station Capacity Evaluation Recycled Water Master Plan Carlsbad Municipal Water District
Booster
Stations
Suction/
Discharge
No. of
Pumps
Total
Capacity
(gpm)
Firm
Capacity
(gpm)
PHD(3)
(gpm)
Balance
(gpm)
Bressi PS 550 to 660 2 duty, 1 standby 4,500 3,000 1,015 +1,985
Calavera PS 384 to 580 2 duty,
1 standby
2,700 1,800 724 +1,076
Twin D PS 384 to 550 3 duty, 1 standby 6,000 4,500 1,903 +2,697
Meadowlark WRF PS WRF to
550
2 duty,
1 standby
-(2) 3,250 2,083 +1,167
Carlsbad WRF PS WRF to
384
3 duty 10,000 6,667 2,777 +3,890
Notes: (1) TDH: Total Dynamic Head.
(2) Total capacity from Meadowlark WRF not reported. Single pump can produce 1,389 gpm and two pumps can product 3,250 gpm. (3) For booster pumping stations, PHD is based on annual downstream demands from Table 2.3, a seasonal
peaking factor of 1.7, and a daily peaking factor of 3.0. For treatment facility pump stations, PHD is based on treatment plant capacity from Table 2.1.
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As shown in Table 8.6, all pump stations are currently adequately sized and meet the
evaluation criteria under existing demand conditions. The Bressi PS and Calavera PS only
need to meet existing PHDs of 1,015 and 724 gpm, respectively. They are currently sized
for 3,000 and 1,800 gpm. The Twin D Pump Station is capable of transferring all of the flow
from the Carlsbad WRF to Zone 550 (approximately 2,700 gpm). Both the Carlsbad WRF
PS and the Meadowlark WRF PS are currently sized to deliver peak effluent production
from their respective plants.
However, it should be noted that the Calavera and Bressi pump stations function as the
sole supply to Zones 580 and 660, respectively. As these pump stations do not have
backup power and these zones do not have gravity storage it is recommended that backup
power be located at each pump station site.
To continue service in these pressure zones during a power outage, both pump stations
need to be equipped with the appropriate switchgear to connect a portable back-up power
generator. It is recommended that CMWD have one portable backup power generator to
continue service during minor power outages, provided that Bressi PS and Calavera PS are
not connected to the same power grid. It is assumed that interruption of recycled water
service would be acceptable during a regional power outage or rolling blackout.
8.4 PUMPING EFFICIENCY AND ENERGY ANALYSIS
The energy analysis evaluated each pump station to determine modifications or operational
changes that could increase pumping efficiency. The PS examined for possible
modifications included:
• Twin D PS
• Bressi PS
• Calavera PS
The Meadowlark WRF PS and Carlsbad WRF PS were not evaluated since their operation
is dependent on the upstream operation of the treatment facility. In addition, both of these
pump stations have either large upstream equalization basin (at Carlsbad WRF) or a large
reservoir (Mahr Reservoir) that allows for optimal pumping of plant effluent.
For the Twin D PS, it is recommended that CMWD operate the pump station at its peak
efficiency operating point, which is possible since excess flow may be deposited into the
Mahr Reservoir. For each individual unit, the best efficiency point is at 1,500 gpm and 300
feet Total Dynamic Head (TDH). Under normal operations (when Meadowlark WRF is
supplying the system), the Twin D PS is not operated on a regular basis. Thus, average
annual energy consumption was not calculated.
January 2012 8-13 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 8.doc
For the Bressi and Calavera PS, CMWD has recently retrofitted each pump station with a
smaller pump capable of more efficiently pumping flow between MinDD and the optimal
flow regime of the existing larger pumps. Prior to the retrofit, the Bressi and Calavera PS
operated only with upstream hydro-pneumatic tanks. As there is no storage upstream of the
Bressi and Calavera PS, the pump station flows must match demand in Zone 580 and Zone
660, respectively. Table 8.7 displays the current demand for each zone and the current
efficiency and kilowatts (kWs) required for pumping at the Bressi and Calavera Pump
Stations, respectively.
Table 8.7 Power Usage for Hydro-pneumatic Zones
Recycled Water Master Plan
Carlsbad Municipal Water District
Booster Stations No. of Pumps Pump Size (gpm) Zone AAD (gpm) Efficiency at AAD(1)
Estimated Power
Usage at
ADD(2)
(kW)
Bressi PS 2 duty, 1 standby 1,080 199 45% 7.2
Calavera PS 2 duty, 1 standby 620 142 56% 3.5
Notes: (1) Based on pump curves provided by CMWD and assumes VFD turndown of at least 50 percent is achievable.
(2) Power usage (kW) estimated based on the pump curves provided by CMWD and ADD.
As shown in Table 8.7, there is low efficiency when one of the existing pumps runs to meet
the indicated demand. In addition, existing pumps are too large to pump flows much lower
than AAD flows without cavitation and backflow that will damage the pumps. A smaller
pump at each pump station runs more efficiently than any of the existing pumps when
pumping flows below the AAD. The increased efficiency associated with the new smaller
pumps both save money and allow the PSs to meet MinDD without damaging the existing
pumps. Approximate energy savings are shown in Table 8.8.
Table 8.8 Summary of Facilities by Pressure Zone
Recycled Water Master Plan Carlsbad Municipal Water District
Booster Stations New Efficiency New kW, ADD Existing kW, ADD kW Savings Cost $/kWh Annual Savings(1)
Bressi 80% 4.3 7.2 2.9 $0.13 $5,000
Calavera 80% 2.5 3.5 1.0 $0.13 $1,500
Notes: (1) Annual savings rounded to nearest $500.
While the annual savings listed in Table 8.8 are not significant, the savings could cover the
cost of a small pump, which is needed regardless, since the large pumps are unable to
pump MinDD. A smaller pump also reduces wear on the larger pumps due to excessive
starting and stopping of the larger pumps.
8-14 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 8.doc
CMWD has recently retrofitted both the Bressi PS and Calavera PS with smaller pumps
capable of both pumping the MinDD and more efficiently pumping flows greater than
MinDD, but less than the optimal pumping regime of the existing pumps. This analysis
confirms this action.
8.5 WATER QUALITY ANALYSIS
The model was used to analyze recycled water quality based on the chlorine residual in the
system. The evaluation was used to determine if CMWD should install additional chlorine
injection stations to maintain adequate chlorine residuals throughout its distribution system.
For this analysis, it was assumed that the chlorine residual of recycled water leaving the
treatment plants would be 9.1 mg/L at Carlsbad WRF and 4.5 mg/L at Meadowlark WRF.
The chlorine residual at the Carlsbad WRF is based on the average chlorine residual
between September 15 and September 30, 2009. The chlorine residual at the Meadowlark
Plant is based on the discussion in Chapter 6. In absence of chlorine jar test data, a global
bulk chlorine decay coefficient of -0.05 along with a default global wall chlorine decay
coefficient of -0.15 were used. These values are consistent with the values used during the
calibration.
Figure 8.3 displays the chlorine residuals in the system as predicted by the hydraulic model.
Under AAD conditions, the major transmission mains in the system (not including small
laterals) maintain a chlorine residual above 2.0 mg/L. Also, the C Tank, Twin D Tanks, and
Mahr Reservoir all have residuals above 2.0 mg/L under AAD conditions. The chlorine
residual for all system reservoir and transmission mains is also above 2.0 mg/L under MMD
conditions.
However, under MinDD conditions, the model predicts that the chlorine residuals in the
C Tank and Mahr Reservoir are 0.02 mg/L and 0.6 mg/L, respectively. The low MinDD
creates a low turnover of water in each reservoir, thereby creating a low chlorine residual.
For MinDD conditions, many of the transmission mains have a residual below 1 mg/L,
especially those mains adjacent to the C Tank. The low residual in the C Tank may be
partially due to the limited cycling within the C Tank as its elevation is above the HGL of
Zone 384. The higher than expected residual within Mahr Reservoir is likely a limitation of
the hydraulic model to adequately predict the increased decay of chlorine residual within a
large, open body of water, as the bulk decay rate within Mahr Reservoir is likely higher than
that observed in the distribution system pipelines.
CMWD could help alleviate the low chlorine residuals under MinDD conditions by installing
a chlorination and mixing system in the low residual reservoirs. CMWD recently completed
installation of a chlorination and mixing system for Mahr Reservoir in 2008. It is
recommended that CMWD considers installing a mixing and chlorination system at the
C Tank to maintain the residual during MinDD periods.
"C" Tank
Carlsbad WRF
Gafner WRP
Mahr Reservoir
Meadowlark WRF
Agua HediondaLagoon
Twin "D" Tanks
E
l
C
a
min
o
R
e
alElm A veMarron Rd
Carlsbad Blvd
Hig
hlan
d D
r
Alondra W ayPaseo Nort
eCollege BlvdPalomar Airport RD
Aviara Pkwy
Costa Ave
P o in s e ttia L nTamarack A veCannon Rd
Calle BarcelonaRanc ho Santa FeCalavera PS
CWRF PS
Bressi PS
"D" Tank PSPacific Ocean
Encinitas
Batiquitos Lagoon
Buena VistaLagoon Oceanside
Shadowridge WRP
OMWDMeter
Corintia Meter
LakeCalavera
J11500.42.32.8
J8740.42.63.2
MWRF4.54.54.5
CWRF9.19.19.1
MAHR0.62.32.6
Four SeasonsResort
La Costa Resort
Kemper SportsManagement
Legoland
Aviara ResortAssociation
San Marcos
Vista
Encinitas
Oceanside
1200.34.05.4
J4002.33.84.0
J1142.83.94.0
TWIND3.07.47.8
J28161.97.07.5
J21581.02.73.3
J21143.07.17.8 J11821.02.83.3
J861.36.16.5
J4763.67.88.5
J24781.35.36.7
J24062.96.57.3
J19580.82.73.1
J18420.82.63.2
J7020.013.54.8
J4240.041.32.1
CTANK0.024.65.6
0 5,000 10,000Feet
Figure 8.3Existing Water System Quality Recycled Water Master PlanCarlsbad Municipal Water DistrictFILENAME: c:\pw_working\projectwise\lwang\d0102644\Figure_8_03-Existing System Water Quality.mxdDATE: 1/14/20110.0 - 1.0 mg/L
1.1 - 2.0 mg/L
2.1 - 4.0 mg/L
4.1 - 6.0 mg/L
6.1 - 9.0 mg/L
Water System Facilities
Pump Station
Pressure Requlating Station (PRS)
Meter
WRF
Tank
Reservoir
Inactive WRP
Other
Freeways
Local Streets
Carlsbad City Limits
San Diego County
Carlsbad Municipal Water District Boundary
Transmission Main Chlorine Residual
Legend
Average Chlorine Residenals (mg/L)
A#.##.##.#
MIN DD (mg/L)
MMD (mg/L)ADD (mg/L)
Model Node ID
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8.6 OPERATIONS AND MAINTENANCE
To keep the existing system operating properly, CMWD may want to start an asset
management program for its recycled water system infrastructure. Although these
infrastructure assets may function for many years with a relatively small amount of
maintenance, these assets will not last forever, and will eventually need to be replaced. The
cost of replacing these assets will be very high. CMWD should therefore start with the
implementation of an overall asset management program so that the best value possible
can be obtained from existing infrastructure and from future infrastructure investments.
As an added benefit of developing an asset management program, CMWD could use such
a program to estimate the remaining useful life of pipelines within its distribution system.
CMWD could then have a basis for establishing an asset renewal fund.
Part of this program would involve inspecting facilities every year or two to track the
condition of system components. Table 8.9 shows typical frequency of inspection and labor
hours for its recycled water facilities.
Table 8.9 Facility Inspection Criteria
Recycled Water Master Plan
Carlsbad Municipal Water District
Facility Frequency of Inspection (years) Hours Required
Pump Stations 3 - 5 1 - 2
Reservoirs 3 - 5 4
Service Connections 1 - 4 1(1)
Large Valve Stations 3 - 5 1 - 2
Pipelines 10 - 12 See Note 2
Notes: (1) Actual test may take up to 24 hours since data is recorded by a pressure logger. Time only accounts for the test preparation.
(2) For the suggested frequency, CMWD should conduct a mass balance to isolate areas that may have leaks. If a leak is found from the analysis, field verification and inspection may be required.
8.7 SUMMARY OF RECOMMENDATIONS
The existing system was found to have a few hydraulic deficiencies, energy deficiencies,
and locations with low chlorine residuals. However, all pump stations are adequately sized
and the system has sufficient storage and supplies.
Hydraulic deficiencies involved locations with high pressures, locations with low pressures,
pipes with high velocities, and pipes with high head loss. Most of the low pressures were
due to higher elevations within the existing zones. Most of the high velocity and high head
loss pipes were not adjacent or in the vicinity of low pressure nodes, with the exception of
two locations. The limited pressure deficiencies caused by these pipelines are not
8-18 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 8.doc
considered severe enough to warrant replacement at this time. However, CMWD should
continue to monitor pressures in the area and, if replacement of these pipeline segments is
warranted for other reasons, replace the pipelines with pipelines of a larger capacity.
All other low-pressure areas do not represent significant deficiencies or are due to higher
elevations within each zone. It is therefore recommended that CMWD continue present
operation without changes, in order to avoid the cost of a new pressure zone and new
pump station, unless the number of customers served by a new zone and pump station
would justify the cost.
The model predicts low chlorine residuals in the C Tank during MinDD condition. This low
residual is consistent with the residual observed during model calibration. To resolve the
deficiencies, the following recommendation was made:
• Install a chlorination and mixing system in C Tank to maintain an adequate residual
during periods of low demand.
The cost for the chlorination and mixing system is included in the capital improvement
program discussed in Chapter 10.
January 2012 9-1 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc
Chapter 9
FUTURE SYSTEM EVALUATION
9.1 INTRODUCTION
This chapter describes the evaluation of alternatives for expansion of the existing system to
maximize service of the potential customers identified in Chapter 3. The evaluation and
sizing criteria described in Chapter 7 are used to size these system expansions. This
chapter is divided into the following three sections:
• Evaluation Methodology. This section discusses the methodology used for the
creation of expansion segments, as well as the selection of the recommended
recycled water system expansion projects.
• Future System Expansion Evaluation. A future recycled water system layout that
serves all potential customers was developed and divided into expansion segments.
This section presents the pipelines and facilities for each expansion segment, which
were sized using the hydraulic model. Planning level cost estimates are also
presented for each expansion segment and are prioritized based on unit cost and
other considerations.
• Future System Recommendations. The expansion segments are compared and a
recommended system is selected for the planning horizon of this recycled water
master plan (RWMP). In addition, the ultimate system under build-out conditions is
described.
The Capital Improvement Program (CIP) for the recommended ultimate build-out system is
described in Chapter 10 of this RWMP.
9.2 EVALUATION METHODOLOGY
For the future system evaluation, the hydraulic model was used to develop potential system
expansion alternatives that can serve the projected demands while meeting the supply and
evaluation criteria constraints. This section discusses the methodology used for the creation
of alternatives and the selection of recommended recycled water system expansion
projects. This methodology includes the following steps:
• Development of the initial system layout
• Division of the initial layout into expansion segments
• Evaluation of redundancy alignments and inclusion of abandoned assets
• Selection of recommended system
The first step in developing a future system is the development of the initial layout of a
potential recycled water system. This system would serve the potential customer demands
with the potential recycled water supplies as discussed in Chapters 3 and 4, respectively.
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Pipeline alignments were laid out in an attempt to provide service to all potential customers.
The pipeline alignments were divided into expansion segments. These expansion segments
were refined with input from CMWD staff, who also identified additional pick-up customers
where feasible, along the proposed pipeline alignments.
Implementation of all expansion segments would maximize the use of recycled water;
however, the total cost of a system serving all potential customers is typically relatively
high. To make expansion of the recycled water system more cost-effective, the various
segments are evaluated based on relative cost expressed in dollars per acre-foot of
demand served. The segments are then prioritized based on this unit cost evaluation and
incorporated into a phased CIP.
9.3 FUTURE SYSTEM EXPANSION EVALUATION
The market assessment conducted in Chapter 3 identified 161 largest customers totaling
5,368 afy (4.8 mgd) as the total potential future system demand in the customer database.
This new demand includes 2,711 afy (2.4 mgd) within CMWD’s service area and 2,657 afy
(2.4 mgd) in the service areas of neighboring agencies. Expansion segments were
developed to maximize the number of customers that could be connected to the recycled
water distribution system. However, several customers were determined to be too distant
from the recycled water distribution system or isolated such that connection to recycled
water would not be viable.
To evaluate the cost effectiveness and priority of the various expansion segments, the
segments were assigned based on contiguous or nearby potential customers. The potential
segments are shown on Figure 9.1. A summary of the potential customer demands by
segment is provided in Table 9.1. Some potential customers were not able to be reached by
the proposed segments; these are summarized separately in Table 9.1 as “Excluded”. In
addition, some potential customers are located adjacent to the existing recycled water
distribution system and do not require a new pipeline. These are labeled “Adjacent to
Existing”.
9.3.1 Expansion Segments
As shown in Table 9.1, the potential demand that can be served if all expansion segments
are implemented is estimated to be 4,662 afy (4.2 mgd). This is calculated by deducting
706 afy of demand that was excluded from the customer database demand of 5,368 afy.
The potential demand of 4,662 afy (4.2 mgd) includes 3,695 afy (3.3 mgd) of demand
associated with conversions of existing potable water customers and 967 afy (0.9 mgd) of
demand associated with new customers (not offsetting existing potable water demands).
While some new demands may not be in place when Phase III is implemented, it is
assumed that all demands will be connected at ultimate build out. For developing unit costs
for each alignment, the ultimate average annual demands were used.
January 2012 9-3 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc
Table 9.1 Demands by Expansion Segment
Recycled Water Master Plan Carlsbad Municipal Water District
Expansion
Segment
Number of
Customers(4)
Average Annual Demand (afy)
Potable Water
Customers
New Demands in
Customer Database(5) Ultimate System(6)
Adjacent to Existing(1) 30 126 472 598
1 19 97 8 105
2 13 782 0 782
3 6 53 280 333
4A(2) 1 448 0 448
4B(2) 9 330 0 330
4C(2) 1 582 0 582
5 16 193 129 322
6 3 20 0 20
7 1 0 64 64
8 2 520 0 520
9 5 65 13 78
10 2 82 0 82
11 16 120 0 120
12 4 41 0 41
13 2 32 0 32
14 2 58 0 58
15 3 22 0 22
16 1 10 0 10
17 6 85 0 85
18 1 31 0 31
Total 143 3,695 967 4,662
Excluded(3) 18 706 0 706
Grand Total 161 4,401 967 5,368
Notes: (1) This category consists of potential customers adjacent to the existing recycled water distribution system
that do not require a specific expansion segment and that can directly connect to the system through a customer lateral. This category is assumed to include 30 service laterals. (2) Three segments are included in Segment 4. Each will be discussed in more detail in Section 9.3.1.
(3) These demands excluded as the associated potential customers were not able to be efficiently connected to the ultimate recycled water distribution system. (4) The specific expansion segment to which each customer is assigned can be found in Appendix C. Note
that the number of customers does not necessarily correspond to the number of service laterals required for retrofit customers. See individual expansion segment descriptions. (5) New Demands are not anticipated to be ready to connect by the time Phase III is completed.
(6) Total of Potable Water Customers and New Demands.
9-4 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc
Each of the segments is described briefly below. As shown as the sum of demands in the
category “Adjacent to Existing”, the customer database identified 598 afy of potential
demand located adjacent to the existing recycled water distribution system, which does not
require an expansion of the system. In addition, potential customers representing 706 afy of
potential demand (shown as “Excluded” in Table 9.1) were not considered viable for
connection to the recycled water distribution system in any of the expansion alternatives
due to the remote location of the customers.
9.3.1.1 Expansion Segment 1
Expansion Segment 1 consists of 15,400 feet of pipeline to serve 19 identified customers
with an ultimate system demand of 105 afy. This segment would be a part of Zone 550.
Expansion Segment 1 is located in the center of CMWD’s service area and consists of
connecting customers in the business park surrounding Palomar Airport Road. While
Phase II identified several of these customers, some of the expansions were not able to be
completed under Phase II. CMWD staff suggested the alignments shown in Expansion
Segment 1. CMWD staff estimated that 58 service laterals will be required to connect
existing potable customers in this expansion segment. Costs for the laterals have been
included in the overall cost for this segment.
It should be noted that a number of cooling tower demands totaling an estimated 44 afy
have been aggregated into Expansion Segment 1. Due to proximity, many of these
demands are for customers that are already on recycled water for irrigation and could be
served without any new pipelines. As discussed in Chapter 3, these demands were
estimated in aggregate and would require an individual connection to each commercial
building as appropriate.
9.3.1.2 Expansion Segment 2
Expansion Segment 2 consists of 17,500 feet of pipeline to serve 13 customers with an
ultimate system demand of 782 afy. This segment would be a part of Zone 384 and extend
the recycled water system north from Carlsbad WRF along Avenida Encinas to the new
power plant and across the lagoon. It is estimated that 18 service laterals will be required to
serve existing potable customers in this expansion segment.
Although previous recycled water studies have placed this expansion segment in a lower
pressure zone, it was decided to raise the hydraulic grade line (HGL) in order to increase
looping in Zone 384 and eliminate a pressure reducing station and booster pumping station.
Preliminary analysis showed maximum pressure along this alignment as 196 psi at an
elevation of 29 ft-msl. Increasing the HGL to Zone 384 will also allow uniform head
conditions for all booster pumps at the Carlsbad WRF Pump Station. In addition, this will
increase redundancy in the distribution system, as supplies from Carlsbad WRF will be
conveyed via transmission mains along Palomar Airport Road and Cannon Road in addition
to the transmission main along Poinsettia Lane.
"C" Tank
Carlsbad WRF
Gafner WRP
Mahr Reservoir
Meadowlark WRF
Agua HediondaLagoon
Twin "D" Tanks
C
a
min
o
R
e
al
E lm A veMarron Rd
C
arls
b
a
d Blv
d
A londra W ayPaseo Nort
eCollege BlvdPalomar Airport
Aviara Pkwy El Fuerte StCosta AvePoinsettia LnTam arack A veCannon Rd
Calle BarcelonaR ancho Santa FeCalavera PS
Bressi PS
"D" Tank PS
Pacific Ocean
Encinitas
Batiquitos Lagoon
Buena VistaLagoon
Oceanside
LakeCalavera
Corintia Meter
OMWDMeter
Carlsbad Village Redundancy Pipeline
4B
4C
8
"
6
"
Santa Fe I Tank
T A P P ip e lin e (n o t in C IP )Pipeline to Santa Fe I
Shadowridge WRP
San Marcos
Vista
Encinitas
Oceanside
17
4A
8
2
3
6
1
9
11
13
12
10
14
7
15 16
185
C017
C032
C177
C176
C175
C174
C173
C179
C170
C169
C168
C166
C178
C165
C164 C163
C162
C161
C064
C159
C158
C126
C116
C157
C156
C155
C153
C152 C151
C150
C149
C148
C147
C146
C145C144
C143
C102
C123
C103
C112
C101
C105
C111
C114
C136C125
C129
C134
C139C121
C124
C115
C113
C128
C108C130
C127 C118
C122
C131C120
C133
C107
C109C140
C141
C137
C135
C104
C093C099
C100
C005 C009
C001
C061C085
C087
C010
C088
C042
C056
C044
C041 C034
C051
C063
C037
C043
C078
C018
C070
C003
C013
C020
C027
C002
C004
C021
C028
0 5,000 10,000Feet
Figure 9.1Potential Expansion SegmentsRecycled Water Master PlanCarlsbad Municipal Water District
FILENAME: c:\pw_working\projectwise\lwang\d0102644\Figure_9_1-Expansions Segment by Color.mxdDATE: 4/26/2011Legend
Existing Recycled Water Pipelines (by Diameter)Less than 6"6" to 8"10" to 14"16" and largerAlready ConstructedRecycled Water FacilitiesPump StationPRS
Meter
WRF
Tank
Reservoir
Inactive WRP
Customer (by demand in afy)<1010-2525-50
50-100
>100
Other FreewaysRailroadsLocal StreetsWater BodyCarlsbad City LimitsSan Diego CountyCarlsbad Municipal Water District Boundary
Potential Expansion Segment
Other (Not for Specific Expansion segment)
Segment 15Protential Golf CourseCustomer
Segment 1
Segment 2
Segment 3
Segment 4A
Segment 4B
Segment 4C
Segment 5
Segment 6
Segment 7
Segment 8
Segment 9
Segment 10
Segment 11
Segment 12
Segment 13
Segment 14
Segment 16
Segment 17
Segment 18
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9.3.1.3 Expansion Segment 3
Expansion Segment 3 consists of 8,600 feet of pipeline to serve 6 customers with an
ultimate system demand of 333 afy. Expansion Segment 3 connects several potential
developments and existing Home Owner’s Association (HOA) customers along College
Blvd and El Camino Real, looping sections of Zone 384 and providing redundancy to the
Calavera Pump Station and Zone 384. This alignment includes 280 afy of demand
associated with new customers in addition to 53 afy of demand from retrofitting existing
potable water customers. Most of this segment would be a part of Zone 384. However, the
proposed Holly Springs HOA would require a higher HGL due to its higher elevation.
As shown, the alignment includes pipelines to the proposed Holly Springs HOA, extending
outside the public right-of-way. However, as development plans become more certain, the
alignment can be planned to follow public streets once they have been determined. Service
to the Holly Springs HOA will require a booster pumping station due to the elevation
difference of about 180 feet. It is anticipated that the developer will provide a small booster
pumping station for serving irrigations demands where the pressures fall too low. The
associated booster pumping station and distribution pipelines for the Holly Springs HOA, as
well as service laterals for all new customers, are assumed to be the responsibility of the
developer and are not included in the CIP.
Note that the Rancho Carlsbad Executive Golf Course is located near the alignment of this
expansion segment, but based on discussions with CMWD staff, it is anticipated that the
golf course will be served from Jackspar Drive, making it a part of Expansion Segment 14.
9.3.1.4 Expansion Segment 4 (VID and Oceanside)
Expansion Segment 4 is intended to evaluate the potential of serving demands within Vista
Irrigation District (VID) and the southeast portion of the City of Oceanside. Three expansion
segments were developed for Expansion Segment 4. These are:
• Expansion Segment 4A – Wholesale Service to VID at Shadowridge Water
Reclamation Plant (WRP)
• Expansion Segment 4B – Retail Service to VID and southeast Oceanside customers
north of Shadowridge WRP
• Expansion Segment 4C – Retail Service to all identified customers within VID south of
Shadowridge WRP
The alignments of each expansion segment are presented on Figure 9.2, Figure 9.3, and
Figure 9.4, while the demand and pipeline lengths are summarized in Table 9.2. As shown
in this table, the ultimate system demand of the three expansion segments totals 1,360 afy.
"C" Tank
El Fuerte StCalavera PS
Bressi PS
Shadowridge WRP
LakeCalavera
Failsafe PipelineC A N N O N R D
MELROSE DRMELROSE DRS U N S E T D R
Connect Failsafe Pipeline to Zone 550
San Marcos
Vista
COLLEGE BLEL CAMINO REAL
C A N N O N R D
PAL OMAR AIRPORT RD
LAKE BL
SHAD OWRIDGE D R
C162
C064
C119
C116
C110
C157
C155
C154
C153
C152
C151
C150
C149
C148
C147
C146
C123
C103
C101
C114
C139
C121C117C115
C109
C098
C076
C009
C008
C061
C055
C086
C054 C073
C071
C085
C044
C003
C019
C013
C026
C012
C090
C015C024
C160
C124
C111
C105
C066
C084
Utilize Existing Pipeline from Shadowridge WRP to Golf course.
C129 C134
Legend
Existing Recycled Water Pipelines (by Diameter)Less than 6"6" to 8"10" to 14"16" and largerExpansion SegmentThis ExpansionOther ExpansionsAlready ConstructedRecycled Water Facilities
Pump Station
Pressure Regulating Station (PRS)
Meter
WRF
Tank
Reservoir
Inactive WRP
Customer (by demand in afy)<1010-25
25-50
50-100
>100
Served in this Alternative
Other FreewaysRailroadsLocal StreetsPotential Golf CoursesWater BodyCarlsbad City LimitsSan Diego CountyCarlsbad Municipal Water District Boundary
0 2,000 4,000Feet
Figure 9.2VID Segment 4ARecycled Water Master PlanCarlsbad Municipal Water DistrictFILENAME: c:\pw_working\projectwise\lwang\d0102644\Figure_9_2-VID Alternative 4A.mxdDATE: 1/14/2011
"C" Tank
Alondra Way
El Fuerte StCalavera PS
Bressi PS
Oceanside
Shadowridge WRP
LakeCalavera
8"
C A N N O N R D
LAKE BL
F a ils a fe P ip e lin e
MaerkleReservoir
MELROSE DRMELROSE DRS U N S E T D R
Alternative Service via Tap connection(Requires Sliplining)
C139
C111
Connect Failsafe Pipeline to Zone 550
San Marcos
Vista5
7
5
7
113 8"8"
8
"
8
"8"8"8"8"8"8"8"
8"8"8"8"8"8"COLLEGE BLEL CA
MINO REAL
C A N N O N R D
PA LOMA R AIRPORT RD MELROSE DR4
8 " S li p lin e 8"12"6 "16"4"
6"
1 2 "
6"12"6"
C162
C158
C119C116
C157
C154
C152
C151
C150
C149
C148
C147
C146
C103
C101
C114
C129
C134
C121C117
C124
C115
C109
C009
C044
C003
C013
C026
C012
C090
0 2,000 4,000Feet
Figure 9.3VID Segment 4BRecycled Water Master PlanCarlsbad Municipal Water DistrictFILENAME: c:\pw_working\projectwise\lwang\d0102644\Figure_9_3-VID Alternative 4B.mxdDATE: 4/18/2011Served in This Alternative
Legend
Existing Recycled Water Pipelines (by Diameter)
Less than 6"
6" to 8"
10" to 14"
16" and largerProposed Expansion SegmentsThis Expansion
Other Expansions
TAP ConnectionAlready ConstructedRecycled Water Facilities
Pump Station
Pressure Regulating Station (PRS)
Meter
WRF
Tank
Reservoir
Inactive WRP
Customer (by demand in afy)<10
10-25
25-50
50-100
>100
OtherFreeways
Local StreetsRailroads
Potential Golf Courses
Water Body
Carlsbad City Limits
Carlsbad Municipal Water District Boundary
"C" Tank
College BlvdPalomar Airport Rd
El Fuerte StCalavera PS
Bressi PS
Oceanside
Shadowridge WRP
LakeCalavera
8"
MaerkleReservoir
EL Camino Real
LAKE BL
SHADOWRIDGE DRCANNON R D MELROSE DRS U N S E T D R
Connect Failsafe Pipeline to Zone 550
C139
12"
Santa Fe I Tank
F a ils a fe P ip e lin e
San Marcos
Vista8"1 2 "
16"4"4"
8 "12"12"6"12"6"
6 "
6"8"6"
6"
6"8"14"12"8"1 2 "6"
4"8"8"
4 "6"4"6"6"6"6"8"8"4"6"6"6"6"
6 "6"6"
4"
C032
C119
C116
C157
C155
C154C153
C152 C151
C150
C149
C148
C147
C146
C123
C103 C111
C114
C129
C134
C121C117
C124
C115
C109
C044
C003
C013
C026
C012
C090
Legend
Existing Recycled Water Pipelines (by Diameter)Less than 6"6" to 8"10" to 14"16" and largerProposed Expansion SegmentsThis ExpansionOther ExpansionsAlready ConstructedCustomer (by demand in afy)<1010-2525-50
50-100
>100
Water System Facilities
Pump Station
PressureRegulating Station (PRS)
Meter
Tank
Inactive WRP
Parcels Served in This Expansion Segment (C101)OtherFreewaysMajor RoadsRailroadsLocal StreetsPotential Golf CoursesWater BodyCarlsbad City LimitsSan Diego CountyCarlsbad Municipal Water District Boundary
0 2,000 4,000Feet
Figure 9.4VID Segment 4CRecycled Water Master PlanCarlsbad Municipal Water District
FILENAME: c:\pw_working\projectwise\lwang\d0102644\Figure_9_4-VID Alternative 4C.mxdDATE: 4/18/2011
January 2012 9-11 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc
Table 9.2 Expansion Segments for Serving Demands in VID (Segment 4)
Recycled Water Master Plan Carlsbad Municipal Water District
Segment
Number of
Customers(3)
Pipeline
Length
(ft)
Booster
Required
Ultimate System
Demand
(afy) Notes
4A 1 700 No 448 Uses Shadowridge WRP for storage
4B 9 23,200 No 330 Includes demand from
Segment 4A
4C 369(1) 63,800 Yes(2) 582 Includes demand from Segment 4A and 4B
Total 379 87,700 1,360
Notes: (1) While listed as one entry in the customer database, the large business park southeast of Shadowridge
WRP served by Expansion Segment 4C actually represents a large number of potential landscape irrigation demands. Considered individually, these demands are quite small. However, CMWD has converted a large number of similar landscape irrigation demands in its own business parks.
(2) A booster station would be required to serve customers connected to segment 4C from the failsafe pipeline. However, Bressi PS could be used to serve these customers directly from CMWD’s existing Zone 660.
(3) Specific customers served by each segment are shown on Figure 9.2, Figure 9.3, and Figure 9.4. Number of customers for Segment 4C is approximated based on the number of parcels.
A list of customers included in each alternative is shown in Table 9.3. Preliminary hydraulic
analysis using the hydraulic model shows that the HGL of Zone 550 will convey sufficient
pressure to directly drive flow through the failsafe pipeline. It is assumed that sufficient
operational storage is available at Shadowridge WRP to buffer the difference between
supply via the failsafe pipeline and recycled water demands over the course of the day.
However, with a ground elevation approximately 440 ft-msl at the Shadowridge WRF, if
existing storage capacity at Shadowridge WRP is used, a pump station would be required
to serve potential customers at an HGL of 550 ft-msl.
Expansion Segment 4A, depicted in Figure 9.2, consists of providing recycled water to
Shadowridge WRP through the existing failsafe pipeline to supply only the demands
associated with the Shadowridge Golf Course.
Expansion Segment 4B, depicted in Figure 9.3, consists of supplying all identified VID and
City of Oceanside (COO) customers that could be supplied at a HGL of 550 ft-msl. Again,
recycled water is provided to Shadowridge WRP through the existing failsafe pipeline.
Recycled water is then supplied to customers through a distribution system from
Shadowridge WRP.
Expansion Segment 4C would serve irrigation demands in the large business park to the
southeast of Shadowridge WRP. The increased elevation of the business park will require
an HGL of about 660 ft-msl. Based on a PHD of 1,840 gpm and a pumping head of
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133 feet, this could be accomplished through a booster pumping station sized at about
90 hp, or by using the existing capacity of the Bressi PS.
Table 9.3 Customer Demands in Expansion Segment 4 Alternatives Recycled Water Master Plan
Carlsbad Municipal Water District
Customer ID Customer Name Existing Purveyor
Ultimate
System Demand (afy) Expansion Segment
C003 Shadowridge Golf Course VID 448 4A
C103 Ocean Hills Country Club COO 148 4B
C111 Buena Vista Park VID 54 4B
C114 Rancho Buena Vista High VID 39 4B
C117 Madison Middle/Lake Elementary COO 34 4B
C121 Lake Park COO 22 4B
C124 New Venture Christian Schools COO 13 4B
C129 Breeze Hill Park VID 11 4B
C134 Breeze Hill Elementary VID 8 4B
C139 Montessori of Oceanside COO 1 4B
C101 Business Park VID 582 4C
It should be noted that demands for the business park (Customer ID C101) were estimated
based on typical water demand factors calculated from existing recycled water demands for
business parks in CMWD’s service area. The business park was not included in VID’s
identified potential customers. Since providing recycled water to the business park would
include a number of retrofit connections, costs for service laterals were included based on
the number of parcels in the business park. A total of 369 service laterals are included in
the cost for this expansion segment.
9.3.1.5 Expansion Segment 5
Expansion Segment 5 consists of 54,200 feet of pipeline to serve 16 customers with an
ultimate system demand of 322 afy. This segment would be a part of Zone 384, extending
the recycled water distribution system north along El Camino Real to serve the second
phase of Robertson’s Ranch, several existing HOAs, and existing landscape irrigation.
9.3.1.6 Expansion Segment 6
Expansion Segment 6 consists of 3,900 feet of pipeline to serve 3 customers with an
ultimate system demand of 20 afy. The La Costa Ridge HOA is currently served recycled
water by a private pump station and existing pipeline near Meadowlark WRF. It is
anticipated that CMWD will take over operation of the pump station and pipeline. Expansion
Segment 6 would build upon this existing pipeline, extending it to serve 3 additional
customers near the La Costa Ridge HOA. Costs are not anticipated or included for
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incorporating the existing private pump station and pipeline into CMWD’s system; rather the
costs for Expansion Segment 6 consist solely of new pipeline to reach the 3 additional
customers. Note that the capacity of the existing pump station was not evaluated; it was
assumed that the pump station would have sufficient spare capacity to accommodate the
additional demands.
9.3.1.7 Expansion Segment 7
Expansion Segment 7 consists of 2,500 feet of pipeline to serve 1 customer with an
ultimate system demand of 64 afy. Expansion Segment 7 provides service to the Quarry
Creek development from Zone 580. Based on an estimated elevation of 117 ft-msl, static
pressures could exceed 200 psi. Thus, a pressure regulator may be required. However, it is
anticipated that this would be constructed on site and paid for by the developer. Based on
input from CMWD staff, it is anticipated that the alignment along Tamarack Avenue and
down the hillside, crossing approximately 300 feet of HOA property outside the public right
of way, is preferable to the alignment along Milford Place or College Boulevard and Marron
Road, portions of which would extend outside CMWD’s service area.
9.3.1.8 Expansion Segment 8 (OMWD and La Costa Resort and Spa)
Expansion Segment 8 consists of 6,500 feet of pipeline to serve La Costa Resort and Spa
and OMWD’s demands lower zone demand with an ultimate system demand of 520 afy.
This segment would be a part of Zone 384. Expansion Segment 8 consists of a pipeline
along El Camino Real, connecting CMWD’s recycled water system to OMWD and existing
landscape irrigation at La Costa Resort and Spa. The feasibility of developing this
alternative depends greatly on the timing of recycled water needs from OMWD.
Alternatively, this alignment could also be used to connect LWWD’s (Leucadia Wastewater
District) currently isolated Gafner WRP distribution system to CMWD’s extensive recycled
water distribution system, assuming appropriately sized pumps would be installed at Gafner
WRP to deliver flows to Zone 384. Based on alternative 4 supply recommendation in
Chapter 4, Gafner would not be utilized as a supply source. If another supply alternative
from Chapter 4 is used, use of Gafner may be beneficial to CMWD.
9.3.1.9 Expansion Segment 9
Expansion Segment 9 consists of 5,800 feet of pipeline to serve 5 customers with an
ultimate system demand of 78 afy. This segment would be a part of Zone 318, expanding
the recycled water system south to the San Pacifico HOA and various existing landscape
irrigation and potential development. A portion of this alignment extends Zone 318 south
along Avenida Encinas to the Poinsettia Village shopping center and the Lake Shore
Garden mobile home park.
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9.3.1.10 Expansion Segment 10 (VWD)
Expansion Segment 10 consists of 3,400 feet of pipeline to serve 2 customers with an
ultimate system demand of 82 afy. This segment would be a part of Zone 550 and would
serve the commercial development in Vallecitos Water District’s (VWD) service area near
Meadowlark WRF. It is anticipated that the south leg of this alignment could be connected
directly to VWD’s pipeline (upstream from CMWD’s meter).
9.3.1.11 Expansion Segment 11
Expansion Segment 11 consists of 25,700 feet of pipeline to serve 16 customers with an
ultimate system demand of 120 afy. This segment would be a part of Zone 384, extending
Expansion Segment 2 north to the Carlsbad Village, serving existing parks, schools, and
landscape irrigation demands in the Carlsbad Village area. The proposed alignment
crosses Interstate 5 at Chestnut Avenue, extending north along the freeway to Holiday
Park, the civic center, and Buena Vista school.
This expansion segment will require either Expansion Segment 2 or Expansion Segments 5
and 12 (with the loop connection along Chestnut Avenue).
9.3.1.12 Expansion Segment 12
Expansion Segment 12 consists of 8,100 feet of pipeline to serve 4 customers
(representing 14 meters) with an ultimate system demand of 41 afy. This segment would be
a part of Zone 384. Expansion Segment 12 extends Expansion Segment 11 north from
Carlsbad Village to several schools.
Pressures for customers at the highest elevation portions of this expansion segment are
predicted by the hydraulic model to be at a minimum of 85 psi.
This alignment is dependent on Expansion Segment 2 and Expansion Segment 11 or
Expansion Segment 5 with the loop connection along Chestnut Avenue.
9.3.1.13 Expansion Segment 13
Expansion Segment 13 consists of 5,900 feet of pipeline to serve 2 customers with an
ultimate system demand of 32 afy. This segment would be a part of Zone 384, serving
customers along Paseo Del Norte and Car Country Drive, connecting the Zone 384
pipelines along Cannon Road and Palomar Airport Road.
9.3.1.14 Expansion Segment 14
Expansion Segment 14 consists of 5,900 feet of pipeline to serve 2 customers with an
ultimate system demand of 58 afy. This segment would be a part of Zone 384 and would
connect the Carlsbad Canterbury HOA and Rancho Carlsbad Executive Golf Course to the
existing recycled water distribution system, connecting some existing recycled water
pipeline segments currently conveying potable water along Jackspar Drive and Frost
January 2012 9-15 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc
Avenue. After development of Expansion Segment 3, this Expansion Segment will connect
the Zone 384 pipeline in Cannon Road with the Zone 384 pipeline in College Boulevard.
Note that the Rancho Carlsbad Golf Course could be served from Expansion Segment 3;
but based on discussions with CMWD staff, it is anticipated that the golf course will be
connected from Jackspar Drive rather than along El Camino Real.
9.3.1.15 Expansion Segment 15
Expansion Segment 15 consists of 2,300 feet of pipeline to serve a total of 9 meters for
4 HOAs (listed as 3 customers in the customer database) with an ultimate system demand
of 22 afy. This segment would be a part of Zone 384, connecting the Viaggio HOA, Aviara
Masters HOA, and Marea to the existing recycled water distribution system. A second leg of
this alignment connects the Tramonto HOA to the existing recycled water distribution
system and can connect to a potential HOA development south of Hummingbird Road.
9.3.1.16 Expansion Segment 16
Expansion Segment 16 consists of 1,400 feet of pipeline to serve 3 meters for the Pavoreal
HOA with an ultimate system demand of 10 afy. This segment would be a part of Zone 384,
connecting the Pavoreal HOA to the existing recycled water distribution system.
9.3.1.17 Expansion Segment 17
Expansion Segment 17 consists of 19,000 feet of pipeline to serve 6 customers with an
ultimate system demand of 85 afy. This segment would be a part of Zone 384, connecting
the HOAs north of La Costa Resort to the existing recycled water system. This alignment
connects the Greenview HOA, Alga Hills HOA, Jockey Club HOA, Alicante Hills HOA, and
the Fairways HOA to the existing recycled water distribution system.
9.3.1.18 Expansion Segment 18
Expansion Segment 18 consists of 5,400 feet of pipeline to serve 17 existing meters (listed
in the customer database as an aggregate of several customers in an area) with an ultimate
system demand of 31 afy. This segment would be a part of Zone 550, connecting several
existing commercial irrigation demands north of Faraday Avenue to the existing recycled
water distribution system.
9.3.2 Other System Expansion Pipelines
In addition to the 18 expansion segments developed to connect potential customers, three
expansion segments were developed for other reasons, including looping, connection to
storage, and increasing redundancy in the system. While cost evaluations for each of these
segments will be presented later in this chapter, a short description of each expansion
segment is provided here. Note that since the purpose of these segments is not to connect
potential customers, they will not be included in the expansion segment unit cost
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development in Section 9.3.3, but cost estimates for each will be discussed later in this
chapter.
9.3.2.1 Redundancy Pipeline for Carlsbad Village
This pipeline would connect Expansion Segment 12 and Expansion Segment 5 to provide a
second supply of recycled water to the Carlsbad Village. This pipeline would consist of
4,200 feet of pipeline. Since Expansion Segments 5 and 12 are both a part of Zone 384, no
pressure regulating or booster pumping stations are anticipated to be required. This
pipeline would also serve as an alternate way to connect Expansion Segment 12 if
Expansion Segment 11 or 2 are not constructed.
9.3.2.2 TAP Pipeline
The Tri-Agency Pipeline (TAP) pipeline consists of a 20-inch diameter pipeline just under
2 miles in length from College Boulevard to Cannon Road across the undeveloped area
south of Lake Calavera. The pipeline was a part of the potable water system and is no
longer necessary. This pipeline could be used as an alternative to repurposing the failsafe
pipeline in Expansion Segment 4 and could serve City of Oceanside demands in Expansion
Segment 4B without using the failsafe pipeline. An evaluation of the costs for sliplining the
TAP pipeline as an alternative to using the failsafe pipeline is included in Section 9.3.9.2.
9.3.2.3 Pipeline to Santa Fe I
The Santa Fe I tank is a 2.5 MG abandoned potable reservoir at an elevation suitable as
gravity storage for Zone 660. While the tank is connected to an abandoned pipeline along
Palomar Airport Road, portions of the pipeline have been destroyed. An alternate alignment
over a shorter distance of 4,200 feet from the north would connect the tank to pipelines
proposed as a part of Expansion Segment 4C. The rehabilitated Santa Fe I tank could then
provide gravity storage for CMWD’s existing Zone 660 as well as customers connected by
Expansion Segment 4C. Further discussion of this pipeline is included in the storage
analysis in Section 9.3.11.
9.3.2.4 Pipelines to Potential Developments
In addition to the potential customers identified in the customer database that would be
served with the expansion segments discussed above, there were additional demands
identified in Chapter 3 that are associated with new developments. Pipelines extending to
these developments are included as a separate category due to the indefinite timing of
these developments.
The demands and pipelines associated with serving these developments were included in
the hydraulic model in order to adequately size the system for build-out demand conditions.
However, unit costs were not developed for it. Development pipelines are shown on the
build-out map for reference, though it is anticipated that more detailed routing and sizing of
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these pipelines should be developed as more details on the developments are made
available.
9.3.3 Alternatives Sizing and Cost Estimates
A pipeline diameter of 8 inches was initially used for all looped pipeline segments. Smaller
diameter pipelines were used for dead end pipelines as discussed in the evaluation criteria
established in Chapter 7. Where found to be deficient using the hydraulic model, pipeline
diameters were increased based on the velocity and head loss criteria specified in
Chapter 7. Where pressures fell below the evaluation criteria of 60 psi, booster stations
were added to specific expansion segments (as noted previously in Section 9.3.1).
The length of pipeline for each alternative and associated preliminary cost estimate is
summarized in Table 9.4. The alignment demands and unit costs presented in Table 9.4
are shown graphically in Figure 9.5 along with the cumulative demand contributed by each
expansion segment. Detailed information on the unit cost development and cost estimate
assumptions are included in Chapter 10. Preliminary conveyance cost estimates are shown
here to aid in prioritization of potential expansion segments.
0
500
1,000
1,500
2,000
2,500
3,000
3,500
4,000
4,500
5,000
$0
$500
$1,000
$1,500
$2,000
$2,500
$3,000
$3,500
$4,000
$4,500
$5,000
0 1 2 3 4A 4B 4C 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Cumulative Additional Demand (afy)Conveyance Unit Cost ($/acre-ft)Conveyance Unit Cost ($/af)Cumulative Demand (afy)
Figure 9.5 Expansion Segment Unit Costs
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As shown in Figure 9.5, the estimated conveyance unit costs range significantly from less
than $100/acre-foot to over $2,500/acre-foot. Note that the other system expansion
pipelines discussed in Section 9.3.2 are not included since their primary purpose is not to
connect potential customers.
Table 9.4 Expansion Segments Preliminary Cost Estimates Recycled Water Master Plan
Carlsbad Municipal Water District
Expansion
Segment
Potential Demand
(afy)
Pipeline Length
(ft)
Capital
Cost(2)
Annual
Cost(3)
Unit
Conveyance Cost
($/af)
0 598 - $185,000 $12,000 $20
1 105 15,400 $3,025,000 $192,000 $1,833
2 782 17,500 $7,700,000 $489,000 $626
3 333 8,600 $1,755,000 $111,500 $335
4A 448 700 $485,000 $31,000 $69
4B 330 23,200 $5,220,000 $331,500 $1,005
4C 582 63,800 $14,820,000 $940,500 $1,615
5 322 54,200 $9,995,000 $634,500 $1,969
6 20 3,900 $725,000 $46,000 $2,330
7 64 2,500 $540,000 $34,500 $535
8 520 6,500 $1,505,000 $95,500 $184
9 78 5,800 $1,090,000 $69,500 $894
10 82 3,400 $650,000 $41,500 $504
11 120 25,700 $4,955,000 $314,500 $2,614
12 41 8,100 $1,545,000 $98,500 $2,391
13 32 5,900 $1,145,000 $73,000 $2,303
14 58 5,900 $1,070,000 $68,000 $1,166
15 22 2,300 $445,000 $28,500 $1,319
16 10 1,400 $265,000 $17,000 $1,753
17 85 19,000 $3,410,000 $216,500 $2,558
18 31 5,400 $1,125,000 $71,500 $2,306
Total(4) 4,662 279,200 $61,495,000 $3,906,500 n/a
Notes: (1) Includes costs for pipelines as well as pressure regulating stations and booster pumping stations as
required. These additional facilities are discussed in Section 9.3.1. (2) Capital Cost includes a construction cost contingency of 20 percent and additional markups for engineering and legal costs of 27.5 percent. Cost estimates and cost assumptions are discussed in
detail in Chapter 9. (3) Annual cost assumes a useful life of 50 years and 6.0 percent interest. (4) Excludes Expansion Segment 19 and thus differs from Table 9.1 total by 4 afy.
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9.3.4 Alternatives Ranking and Prioritization
The expansion segments presented in Section 9.3.1 were prioritized based on unit
conveyance cost estimates presented in Table 9.4. The resulting ranking is presented in
Table 9.5 and graphically shown in Figure 9.6. This figure also shows the cumulative
demand added to the existing system if all expansion segments were constructed in the
order of increasing unit cost. The total cumulative demand listed in Table 9.5 includes
CMWD’s existing and near-term demands as well as all potential demands discussed in
Chapter 3.
Table 9.5 Expansion Segments Ranking Recycled Water Master Plan
Carlsbad Municipal Water District
Rank
Expansion
Segment
Pipeline Length
(ft)
Capital
Cost(1)
Alignment Unit Cost
($/af)
Cumulative
Potential Demand
(afy)
Total
Cumulative Demand
(afy)(2)
0 0 - $185,000 $20 598 4,215
1 4A 700 $485,000 $69 1,046 4,663
2 8 6,500 $1,505,000 $184 1,566 5,183
3 3 8,600 $1,755,000 $335 1,898 5,515
4 7 2,500 $460,000 $458 1,963 5,580
5 10 3,400 $650,000 $504 2,045 5,662
6 2 17,500 $7,700,000 $626 2,827 6,444
7 9 5,800 $1,090,000 $894 2,904 6,521
8 4B 23,200 $5,220,000 $1,005 3,234 6,851
9 14 5,900 $1,070,000 $1,166 3,293 6,910
10 15 2,300 $445,000 $1,319 3,314 6,931
11 4C 63,800 $14,820,000 $1,615 3,896 7,513
12 16 1,400 $265,000 $1,753 3,906 7,523
13 1 15,400 $3,025,000 $1,833 4,011 7,628
14 5 54,200 $9,995,000 $1,969 4,333 7,950
15 18 5,400 $1,045,000 $2,145 4,364 7,981
16 13 5,900 $1,145,000 $2,303 4,396 8,013
17 6 3,900 $725,000 $2,330 4,416 8,033
18 12(3) 8,100 $1,545,000 $2,391 4,457 8,074
19 17 19,000 $3,410,000 $2,558 4,541 8,158
20 11(3) 25,700 $4,955,000 $2,614 4,662 8,279
Total(4) 279,200 $61,495,000 4,662 8,279
Notes: (1) Cost estimates and cost assumptions are discussed in detail in Chapter 9.
(2) Includes existing plus near-term demand of 3,617 afy (based on reduced 2010 demands). (3) Expansion Segment 12 requires implementation of Expansion Segment 11, which requires Expansion Segment 2.
(4) Excludes Expansion Segment 19 and thus differs from Table 9.1 total by 4 afy.
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As shown in Table 9.5, if all expansion segments are implemented, approximately 4,662 afy
of demand would be added to CMWD’s system at a total capital cost of about $61 million
for distribution system components. This equates to an average unit capital distribution
system cost of $837 per acre-foot.
0
500
1,000
1,500
2,000
2,500
3,000
3,500
4,000
4,500
5,000
$0
$500
$1,000
$1,500
$2,000
$2,500
$3,000
$3,500
$4,000
$4,500
$5,000
0 4A 8 3 7 10 2 9 4B 14 15 4C 16 1 5 18 13 6 12 17 11 Cumulative Demand (afy)Conveyance Unit Cost ($/acre-ft)Phase III Expansion Segments Build-out Expansion Segments Cumulative Potential Demand (afy)
Note: Conveyance costs do not include treatment costs.
Figure 9.6 Expansion Segment Unit Costs
As shown in Figure 9.6 the incremental new demand decreases after implementation of
Expansion Segment 4C, while the unit cost for conveyance continues to increase. Since
implementation of Expansion Segment 4C will require significant inter-agency coordination
and because this segment marks the point where the unit conveyance cost exceeds
$1,500/acre-foot, it was decided to define all segments up through Expansion Segment 15
as Phase III and categorize the remaining segments for the Build Out.
Details regarding Phase III and the Build Out Phase are discussed in more detail below.
9.3.5 Preferred Alternative - Phase III
As shown in Table 9.5 and Figure 9.6, the unit conveyance costs (not including treatment
costs) for expansion segments after Expansion Segment 15 exceed $1,500 per acre-foot. If
all expansion segments below $1,500 per acre-foot are included in Phase III, this Phase will
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capture approximately 71 percent of the remaining potential demand. A summary of the
demands and costs of the Phase III expansion segments is presented in Table 9.6.
Table 9.6 Preferred Alternative – Phase III
Recycled Water Master Plan Carlsbad Municipal Water District
Expansion
Segment
Retrofit
AAD(1)
(afy)
Ultimate
AAD(1)
(afy)
Pipeline
Length
(ft)
Capital
Cost(2,3)
Alignment
Unit Cost(4)
($/af)
0 126 598 - $185,000 $20
4A(5) 448 448 700 $485,000 $69
8 520 520 6,500 $1,505,000 $184
3 53 333 8,600 $1,755,000 $335
7 0 64 2,500 $460,000 $458
10 82 82 3,400 $650,000 $504
2 782 782 17,500 $7,700,000 $626
4B 330 330 23,200 $5,220,000 $1,005
9 65 78 5,800 $1,090,000 $894
14 58 58 5,900 $1,070,000 $1,166
15 22 22 2,300 $445,000 $1,319
Total 2,485 3,314 76,400 20,565,000 $378(6)
Notes: (1) Phase III AAD includes temporary agricultural demands but excludes development demands, which are
not anticipated to be fully in place by the time Phase III is constructed. Ultimate AAD includes development demands, but excludes agricultural demands, which will be replaced by development. (2) Includes costs for pipelines as well as pressure regulating stations and booster pumping stations as
required. These additional facilities are discussed in Section 9.3.1. (3) Capital Costs include a construction cost contingency of 20 percent and additional markups for engineering and legal costs of 27.5 percent. Cost estimates and cost assumptions are discussed in
detail in Chapter 10. (4) Unit cost assumes a useful life of 50 years and 6.0 percent interest. (5) Pipeline lengths for Expansion Alternative 4A are not anticipated to be significant due to the utilization of the existing unused failsafe pipeline from Shadowridge. (6) Overall unit cost for all expansion segments listed as a part of Phase III.
As shown in Table 9.6, it is estimated that Phase III demand of the segments listed in this
table will add approximately 3,314 afy of new demand to CMWD’s existing recycled water
system for a distribution system capital cost of about $20 million.
It is anticipated that the implementation of Phase III will take approximately 10 years,
five years for building the infrastructure to support Phase III and five years to connect the
customers. The combined unit cost of the expansion segments of Phase III without
treatment is estimated at $394 per acre-foot. The total Phase III demand with the existing
and near-term demand of 4,100 afy is estimated to reach about 7,414 afy.
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9.3.6 Preferred Alternative - Build Out
The remaining expansion segments are included in the Build-Out Phase. Expansion
segments recommended for potential incorporation into the Build-Out Phase are listed in
Table 9.7.
Table 9.7 Preferred Alternative – Build-out Phase
Recycled Water Master Plan Carlsbad Municipal Water District
Expansion
Segment
Ultimate
System
Demand (afy)
Pipeline
Length
(ft)
Capital
Cost(1,2)
Alignment Unit
Cost(3) ($/af)
4C 582 63,800 $14,820,000 $1,615
16 10 1,400 $265,000 $1,753
1 105 15,400 $3,025,000 $1,833
5 322 54,200 $9,995,000 $1,969
13 32 5,900 $1,145,000 $2,303
18 31 5,400 $1,045,000 $2,145
6 20 3,900 $725,000 $2,330
12(2) 41 8,100 $1,545,000 $2,391
17 85 19,000 $3,410,000 $2,558
11 120 25,700 $4,955,000 $2,614
Total 1,348 202,800 $40,930,000 $1,927(4)
Development of
Vacant Land 344
Total with Vacant Land
Development 1,692
Notes: (1) Includes costs for pipelines as well as pressure regulating stations and booster pumping stations as required. Such additional facilities are discussed in Section 9.3.1.
(2) Capital Costs include a construction cost contingency of 20 percent and additional markups for engineering and legal costs of 27.5 percent. Cost estimates and cost assumptions are discussed in detail in Chapter 9. (3) Unit cost assumes a useful life of 50 years and 6.0 percent interest. (4) Overall unit cost for all expansion segments.
As shown in Table 9.7, it is anticipated that the segments included in the Build Out Phase
will connect about 1,348 afy of potential customer demands for a distribution system capital
cost of nearly $41 million. The overall unit conveyance cost of these expansion segments is
$1,927 per acre-foot. The appropriate timing on incorporating these more costly system
expansions will greatly depend on the future development of potable water cost, availability,
and reliability. CMWD should continue monitoring development plans near these expansion
segments, as additional potential demands may make these expansion segments more
economically viable.
January 2012 9-23 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc
CMWD’s service area also includes potential areas of new development for which there is
limited information on timing as discussed in Section 3.5.8. Demands for these areas were
estimated at 344 afy. The demand for these potential areas of new development was
included in the sizing of pipelines and future treatment plant expansions. However, the
conveyance cost for serving these vacant areas are not included in the CIP as the onsite
development piping is typically paid for by the developers. The alignments shown on the
maps may not follow the layout of the eventual tracts and are only intended to show the
potential location of developments. The proposed build out system by pressure zone along
with the locations of booster pumping stations and pressure regulating stations is shown on
Figure 9.7.
9.3.7 Summary of Demand Projections
Based on the phasing of expansion segments discussed previously, the water demands for
each phase were estimated as shown in Table 9.8. This table summarizes the projected
demands under average annual, average day, and maximum month conditions for each
phase.
Table 9.8 Summary of Demands by Phase Recycled Water Master Plan
Carlsbad Municipal Water District
Phase
Ultimate
System Demand (afy)
Average
Day Demand (mgd)
Maximum
Month Demand(2) (mgd)
Existing + Near Term 4,100 3.7 6.3
Phase III Expansion Segments(1) 3,314 2.9 4.7
Phase III Subtotal 3,314 2.9 4.7
Phase III Total 7,414 6.6 11.0
Build Out Expansion Segments 1,348 1.2 2.0
Development of Vacant Land 344 0.3 0.5
Build-Out Phase Subtotal 1,692 1.5 2.5
Ultimate System Total 9,106 8.1 13.5
Notes: (1) Assumes that all potential customers adjacent to the existing system are connected during Phase III (2) MMD peaking factors vary by customer (see Appendix C for details).
As shown in Table 9.8, a total of 9,106 afy of demand was identified as the ultimate system
demand. It is estimated that the total Phase III demand would be approximately 7,414 afy.
In addition to a breakdown by phase, demands are presented by service area in relative to
CMWD’s service area boundary (inside versus outside) in Table 9.9.
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Table 9.9 Potential Demand Outside CMWD’s Service Areas
Recycled Water Master Plan Carlsbad Municipal Water District
Phase
Demand by Agency (afy)
CMWD VID Oceanside VWD OMWD Total
Existing 4,100 0 0 0 0 4,100
Phase III 1,954 560 218 82 500 3,314
Build-out 746 582 - 20 - 1,348
New Development 344 0 - - - 344
Total Ultimate 7,143 1,142 218 102 500 9,106
Not Feasible 11 16 37 455 187 706
Total Potential 7,155 1,158 255 557 687 9,812
As shown in Table 9.9, the new Phase III demand associated with customers inside
CMWD’s service area is 1,954 afy (59 percent) of the total Phase III demand, while the
remaining 1,360 afy (41 percent) is located in the service areas of neighboring agencies.
During the Build-Out Phase, it is estimated that CMWD could serve an additional 746 afy
while about half of the demand in this phase (602 afy) is located outside CMWD’s service
area. This means that under Ultimate System Conditions, approximately 27 percent of the
total build out demand of 9,106 afy would be served to customers outside CMWD’s service
area.
9.3.8 Supply Strategy
As discussed in Chapter 4, the recommended supply alternative consists of the expansion
of Carlsbad WRF, abandoning Gafner WRP, and continued utilization of Meadowlark WRF.
The recommended supply strategy is to utilize Meadowlark WRF as CMWD’s baseline
supply and Carlsbad WRF as CMWD’s peaking supply while incorporating seasonal
storage as possible. Figure 9.8 and Figure 9.9 show how this supply strategy would meet
the seasonal variation of demand on a monthly basis under Phase III and Ultimate demand
conditions, respectively.
"C" Tank
Carlsbad WRF
Gafner WRP
Mahr Reservoir
Meadowlark WRF
Agua HediondaLagoon
Twin "D" TanksCam
i
n
o
R
e
a
l
Elm Ave
Marron Rd
C
a
r
l
s
b
a
d
B
l
v
d
Hi
g
h
l
a
n
d
D
r
Paseo
No
rte College BlvdPalomar Airport RD
Aviara Pkwy El Fuerte StCosta AvePoinsettia LnTamarack Ave
Cannon Rd
Calle B
a
r
c
e
l
o
n
a Rancho Santa FeCalavera PS
Bressi PS
"D" Tank PSPacific Ocean
Encinitas
Batiquitos Lagoon
Buena VistaLagoon Oceanside
Shadowridge WRP
LakeCalavera
Corintia Meter
OMWDMeter
8"
Santa Fe Tank I
MaerkleReservoir
TAP Pipeline (not in CIP)
San Marcos
Vista
Encinitas
Oceanside
C017
C032
C177
C176C175
C174
C173
C172 C179
C170
C169
C168
C166
C178
C165
C164 C163
C162
C161
C064
C159
C158
C126
C119C116
C157
C156
C155
C153
C152 C151
C149
C148
C147
C146
C145
C144
C143 C102
C123
C103
C112
C101
C105
C111
C114
C136C125
C129
C134
C139C121
C124
C115
C113
C128
C108C130
C127 C118
C122
C131C120
C133
C107
C109C140
C141
C137
C135
C104
C093C099
C100
C005 C009
C001
C059
C050
C053
C061C065C071
C087
C010
C088
C042
C056
C044
C041 C034
C051
C063
C037
C043
C078
C018
C070
C045
C014C038
C003
C013
C020
C027
C026
C002
C004
C012
C021
C028
C102
C105
C115
C108
C118
C120
LegendExisting Recycled Water Pipelines (by Pressure Zone)318384550580660Potential Expansion Segments (by Pressure Zone)318384550580660Recycled Water Facilities
Pump StationPRS
Meter
WRF
Tank
Reservoir
Rehabilitate Abandoned Tank
Inactive WRPCustomer (by demand in afy)<1010-2525-50
50-100
>100
Proposed Facilities
New PRS/Valve
OtherFreewaysRailroadLocal StreetsFailsafe PipelineCarlsbad Municipal Water District BoundaryWater BodyCarlsbad City LimitsSan Diego County
0 5,000 10,000Feet
Figure 9.7Build Out System by Pressure ZonesRecycled Water Master PlanCarlsbad Municipal Water DistrictFILENAME: C:\pw_working\projectwise\jdmeyerhofer\d0102644Figure_9_7-Proposed Presure Zone.mxdDATE: 1/17/2012Not Feasible Indicated by Grey
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January 2012 9-27 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc
Figure 9.8 Phase III Supply Strategy
Figure 9.9 Build Out Supply Strategy
2.0 2.0 2.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 2.0
0.9 0.8 1.2
4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0
2.4
0.2 2.3 4.2 5.8 6.4 4.9 4.1
0.2
0
2
4
6
8
10
12
14
16
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Average Daily Demand During Month
(mgd)
Meadowlark WRF Carlsbad WRF Carlsbad WRF Expansion Average Daily Demand During Month (mgd) 2.0 2.0 2.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 2.0
0.4 0.3 0.6
2.9 4.0 4.0 4.0 4.0 4.0 4.0 2.9
0.0
0.6 2.1 3.5 4.0 2.7 2.0
0
2
4
6
8
10
12
14
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Average Daily Demand During Month
(mgd)
Meadowlark WRF Carlsbad WRF Carlsbad WRF Expansion Average Daily Demand During Month (mgd)
9-28 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc
As shown in Figure 9.8, the Carlsbad WRF needs to be expanded by about 4.0 mgd to
meet the MMD of 11.0 mgd. It is assumed that the existing 4-mgd plant would be expanded
by 4 mgd to 8 mgd to meet the Phase III demands. The capital cost, details of which are
discussed in Chapter 10, is estimated at $7.0 M. Based on the seasonal peaking factor of
1.7, the existing MMD supply capacity of 7.6 mgd corresponds to an average annual
demand of 5,008 afy. Based on an average annual Phase III demand of 7,414 afy, the
expansion is assumed to add 2,406 afy of potential demand. Based on an annual demand
increase of 2,406 afy made possible by this expansion, the unit cost would be $211 per
acre-foot for capital costs.
As shown in Figure 9.9, the Carlsbad WRF needs to be expanded by 6.4 mgd to meet the
projected built out demand of 13.5 mgd. For planning purposes, it is assumed that the
existing 4-mgd plant would be expanded by 7 mgd, or 3 mgd of additional capacity after
completion of Phase III. The estimated capital cost, details of which are discussed in
Chapter 10, is estimated at $5.5 M. Based on an average annual build out demand of
9,106 afy, the expansion is assumed to add 1,692 afy of potential demand beyond the
capacity of the Phase III system. Based on an annual demand of 1,692 afy made possible
by this expansion, the unit cost would be $236 per acre-foot.
Note that the unit cost developed in Chapter 4 is based on a single 7-mgd expansion rather
than two expansions, the first phase of 4-mgd and the second phase of 3-mgd.
As discussed in Chapter 4, using seasonal storage in Mahr Reservoir could reduce the
required treatment capacity at Carlsbad WRF by about 1 mgd for one month in the entire
summer. As shown in Figure 9.10, using Mahr Reservoir as a source of supply in the
maximum months can reduce the required build out expansion from 6.4 mgd to 6.0 mgd.
However, using seasonal storage to this degree will require very strict accounting and
operations of the water in Mahr Reservoir in order to avoid running short on supplies in the
maximum month. If demands peak higher in a year due to higher temperatures or low
rainfall, supply shortfalls could ensue. It is therefore recommend expanding the Carlsbad
WRF by 7 mgd and only using Mahr Reservoir as seasonal and emergency storage backup
supply.
January 2012 9-29 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc
Figure 9.10 Build Out Supply Strategy with Seasonal Storage
9.3.9 Utilization of Abandoned Assets
As discussed in Chapter 2, CMWD has identified several abandoned assets that could
potentially be utilized to minimize CMWD’s new capital expenditures. This analysis
evaluated the potential cost benefit of using the existing abandoned assets.
9.3.9.1 Existing 20-inch Pipeline along El Camino Real
An abandoned 20-inch diameter pipeline runs 3.5 miles along El Camino Real from
Faraday Avenue to Chestnut Avenue. The pipeline was originally part of CMWD’s potable
distribution system. Expansion Segments 3 and 5 include approximately 2.2 miles of 8-inch
diameter pipeline following the alignment of the abandoned pipeline.
It is anticipated that utilizing this pipeline would require sliplining the 20-inch diameter
abandoned pipeline with an 8-inch diameter pipeline for the recycled water system. The
anticipated capital costs associated with utilizing the abandoned asset, along with the
anticipated cost savings resulting from not installing a new parallel pipeline, are shown in
Table 9.10.
2.0 2.0 2.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 2.0
0.9 0.8 1.2
4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0
2.4
0.2 2.3 4.2 5.6 5.7 4.9 4.1
0.2
0.25 0.75
0
2
4
6
8
10
12
14
16
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Average Daily Demand During Month
(mgd)
Meadowlark WRF Carlsbad WRF
Carlsbad WRF Expansion Mahr Reservoir Seasonal Storage Average Daily Demand During Month (mgd)
9-30 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc
Table 9.10 El Camino Real Abandoned Pipeline Alternative
Recycled Water Master Plan Carlsbad Municipal Water District
Alignment
Pipeline
Segment
Length (ft)
Estimated
Construction Cost(1) Capital Cost(2)
Capital Cost
without
Abandoned Asset(3) Difference(4)
3 2,300 $200,000 $310,000 $530,000 $220,000
5 9,600 $820,000 $1,255,000 $2,205,000 $950,000
Total 11,000 $1,020,000 $1,565,000 $2,735,000 $1,170,000
Notes: (1) Includes costs for sliplining based on unit costs discussed in Chapter 10.
(2) Capital Costs include a construction cost contingency of 20 percent and additional markups for engineering and legal costs of 27.5 percent.
(3) Capital Cost for component of pipeline along El Camino Real that could be substituted by utilization of abandoned asset. This is a portion of the capital cost listed in Table 9.4 for each
alternative. (4) Anticipated savings from utilization of abandoned asset.
As shown in Table 9.10, it is anticipated that utilization of the abandoned pipeline along
El Camino Real could result in a cost savings of nearly $1.2 million.
9.3.9.2 Existing 21-inch TAP Connection
A 21-inch diameter pipeline runs across natural open space from College Boulevard to
Cannon Road south of Lake Calavera. The pipeline was part of the potable water system
and CMWD currently plans to replace this pipeline. This pipeline could be used as an
alternative to repurposing the failsafe pipeline in Expansion Segment 4. It is estimated that
about 2 miles of the pipeline would be useful as a transmission main for recycled water to
supply Oceanside customers (identified as a part of Expansion Segment 4B).
It is anticipated that utilizing this pipeline would require sliplining the 21-inch diameter
abandoned pipeline with an 8-inch diameter pipeline for the recycled water system. The
anticipated capital costs associated with utilizing the abandoned asset, along with the
anticipated additional cost to Expansion Segment 4B, are shown in Table 9.11.
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Table 9.11 TAP Connection Alternative
Recycled Water Master Plan Carlsbad Municipal Water District
Alt.
Pipeline Segment
Length
(ft)
Estimated
Construction
Cost(1)
Capital
Cost(2)
Original
Capital Cost of
Alternative
4B
Capital
Cost of
Alternative 4B with
TAP
Alternative Difference
4B 10,800 $920,000 $1,410,000 $5,220,000 $6,630,000 $1,410,000
Total 10,800 $920,000 $1,410,000 $5,220,000 $6,630,000 $1,410,000
Notes: (1) Includes costs for sliplining based on unit costs discussed in Chapter 10.
(2) Capital costs include a construction cost contingency of 20 percent and additional markups for engineering and legal costs of 27.5 percent.
As shown in Table 9.11, it is anticipated that total capital cost if Alternative 4B was to use
the TAP connection would be approximately $6.6 M, a $1.4 M additional cost over using the
failsafe pipeline for delivery of recycled water to VID and Oceanside. However, the
development of Expansion Segment 4 costs has assumed that the failsafe pipeline will be
provided at no cost. This pipeline could serve as an alternative should the pipeline
acquisition exceed this cost difference. In addition, if VID customers were not supplied as a
part of Expansion Segment 4, the pipeline could serve as an alternative to allow service of
Oceanside customers without needing to cross into VID’s service area.
Note that, if Expansion Segment 4A is not implemented, this could potentially save the
costs of connecting to the failsafe pipeline associated with Expansion Segment 4A.
9.3.10 Redundancy
9.3.10.1 Redundancy Pipeline for Carlsbad Village
Expansion Segments 11 and 12 would be served through a single pipeline from Expansion
Segment 2. To limit the potential for service interruptions, Expansion Segment 12 and
Expansion Segment 5 could be looped with a 0.5-mile pipeline, allowing for redundancy in
supplying the Carlsbad Village area. The estimated capital cost associated with adding this
0.5-mile pipeline is shown in Table 9.12.
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Table 9.12 Redundancy Pipeline for Carlsbad Village
Recycled Water Master Plan Carlsbad Municipal Water District
Alignment
Diameter
(in)
Pipeline
Length (ft)
Estimated
Construction
Cost(1) Capital Cost(2)
Chestnut Ave. from Valley
Street to El Camino Real
12 4,200 $630,000 $965,000
Notes: (1) Based on unit costs discussed in Chapter 10.
(2) Capital costs include a construction cost contingency of 20 percent and additional markups for engineering and legal costs of 27.5 percent.
As shown in Table 9.12, it is anticipated that total capital cost for a pipeline between
Expansion Segments 5 and 12 would be approximately $1.0 M.
9.3.10.2 Supply of Full System without Meadowlark WRF
CMWD currently has the capability to maintain full supply of its recycled water system
under MMD conditions with the ultimate supply capacity of Carlsbad WRF and with the
supplemental potable connection at the Twin D Tanks, while Meadowlark WRF is offline.
This analysis evaluates the additional capacity necessary to supply MDD conditions under
built out conditions with Meadowlark WRF offline and the Gafner WRP no longer available.
The results are shown in Table 9.13.
Table 9.13 Analysis of Supply without Meadowlark WRF Recycled Water Master Plan
Carlsbad Municipal Water District
Source
Built Out Capacity/Demand (mgd)
Built Out Capacity/Demand(1) (gpm)
Ultimate Carlsbad WRF 11.0 7,600
Potable Supplement 4.3 3,000
Total 15.3 10,600
Maximum Month Demand(2) 13.5 9,400
Balance +1.8 +1,200
Notes: (1) Although capacity is shown in units of gpm, supplies are calculated for maximum month demand
conditions. Operational storage to accommodate daily peaking is discussed in Section 9.3.11. (2) MMD from build-out system including areas of potential development and neighboring agencies in addition
to potential customers identified within CMWD’s service area.
As discussed in Chapter 2, the existing potable water connection can supply 3,000 gpm of
supplement water. Based on the supply analysis presented in Section 9.3.8, the ultimate
supply capacity of Carlsbad WRF is recommended to be increased from 4 to 11 mgd.
January 2012 9-33 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc
As Zone 550 and Zone 660 typically receive flow from Meadowlark WRF, the Twin D pump
station must be sized to meet demands of both of these zones (as the potable supplement
connection and the Carlsbad WRF feeds Zone 384). Table 9.14 presents an analysis of the
capacity of the Twin D pump station under ultimate demand conditions. This analysis is
conducted under MMD conditions since operational storage is recommended to be
incorporated into Zone 550 to accommodate daily peaking (see Section 9.3.11).
Table 9.14 Twin D Capacity Analysis
Recycled Water Master Plan Carlsbad Municipal Water District
Booster Station
Existing
Pump Station Capacity
(gpm)
Built Out
Zone 550 and 660 MMD
(mgd)
Built Out
Zone 550 and 660 MMD(1)
(gpm)
Twin D 4,500 4.9 3,400
Notes: (1) As discussed in Section 9.3.11, operational storage is recommended to be included in Zone 550 to accommodate daily peaking.
As shown in Table 9.14, the existing capacity of the Twin D pump station is sufficient to
meet Maximum Day Demands for Zones 550 and 660 of the built out system. It should be
noted that the pump station cannot accommodate peak hour demands of Zones 550 and
660. As discussed in Section 9.3.11, the storage analysis recommends operational storage
within Zones 550 and 660.
9.3.11 Storage Analysis
The storage analysis evaluates the existing storage capacity based on the evaluation
criteria in Chapter 7 for operational and emergency storage. A definition for each category
of storage criteria is summarized below.
• Operational Storage: The storage required to buffer demand fluctuations under
maximum day demand (MDD) conditions. The required operational storage is defined
as 33 percent of MDD.
• Short-term Emergency Storage: The storage volume required for preventing a
reservoir from completely draining during an emergency situation such as a
temporary supply outage or a demand spike. The required emergency storage is
defined as 17 percent of MDD.
A third component of storage used in CMWD’s system, seasonal storage, is treated as a
source of supply and is discussed in more detail in Chapter 4.
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As described in Chapter 8, CMWD currently has 35.5 MG of storage, 32.0 MG of which is
available in Mahr Reservoir.
Operational and emergency storage requirements were calculated based on the evaluation
criteria. Demands for Zone 742 (La Costa Ridge) are incorporated into Zone 550. For
Zones 318 and 580, the reservoir capacity is assumed to be located in the larger Zone 384,
from which each of these zones will be supplied. For Zones 550 and 660, demand in the
existing system does not require operational storage as Meadowlark WRF supplies a
greater flow than the demand of Zones 550 and 660. However, for the future system, it is
anticipated that storage will be required for Zones 550 and 660 once demands in
Zones 550 and 660 exceed available supply from Meadowlark WRF on a MMD basis.
Note that demands for the La Costa Resort and Spa south golf course are incorporated into
Zone 384, since the recommended supply alternative would include abandonment of
Gafner WRP; although currently, operational storage for the La Costa Resort and Spa
south golf course is provided by on-site ponds. Total future required operational and
emergency storage requirements are compared to the existing storage in Table 9.15.
Table 9.15 Storage Capacity Evaluation for Build-out Recycled Water Master Plan
Carlsbad Municipal Water District
Zone
Built
Out MMD
(mgd)
Operational Storage(1,2)
(MG)
Short-Term
Emergency Storage(1,3)
(MG)
Total
Required Storage
(MG)
Existing Storage
(MG)
Balance
(MG)
660 0.6 0.2 0.1 0.3 0.0(4) -0.3
550 4.2 1.4 0.7 2.1 0.0(4) -2.1
Subtotal 4.8 1.6 0.8 2.4 0.0(4) -2.4
Subtotal w/ Mahr 4.8 1.6 0.8 2.4 32.0(4) +29.6
580 0.4 0.2 0.1 0.2 0.0 -0.2
384 8.0 2.7 1.4 4.0 3.5 -0.5
318 0.2 0.1 < 0.1 0.1 0.0 -0.1
Subtotal 8.7 2.9 1.5 4.3 3.5 -0.8
Total w/o Mahr 13.5 4.4 2.3 6.7 3.5 -3.2
Total w/ Mahr 13.5 4.4 2.3 6.7 35.5 +28.8
Notes: (1) Operational and Emergency Storage requirements are based on the evaluation criteria from Chapter 7.
(2) Based on the evaluation criteria, Operational Storage is 33 percent of the MMD. (3) Based on the evaluation criteria, Emergency Storage is 17 percent of the MMD, or four hours. (4) Supplies from Meadowlark WRF are taken at a constant rate greater than the demand of Zones 550 and
660. Consequently, Operational Storage for Zone 550 is not needed. When necessary, Mahr Reservoir can be used to buffer supplies at Meadowlark WRF.
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As shown in Table 9.15, a deficit of 3.2 MG is anticipated at build-out if capacity in Mahr
Reservoir is not considered.
Zone 550 and Zone 660 is grouped together as these zones are both fed from Meadowlark
WRF. As shown in Table 9.15, a total storage volume of 2.4 MG is required for these
zones. If there is sufficient MMD supplies such that capacity within Mahr Reservoir is not
needed for seasonal storage, the required storage could be satisfied through use of Mahr
Reservoir, assuming CMWD develops a method of replenishing Mahr Reservoir from its
other supply sources (since daily demand in Zone 550 and Zone 660 will exceed supply
from Meadowlark WRF). Otherwise, it is recommended that the ultimate system include
2.5 MG of new storage capacity for Zone 550. This can be met by rehabilitating the 2.5 MG
Santa Fe I tank in Zone 660.
Note that the demands for expansion segment Alternative 4C are used to calculate this
storage requirement. The total required storage volume will be significantly less if
Alternative 4C is not implemented.
Zones 318, 384, and 580, as well as proposed Zones 425 and 742, are grouped together
as these zones are all planned to be fed from Carlsbad WRF (Zone 384). As shown in
Table 9.15, a total of 0.8 MG of storage is required for these zones. The hydraulic model
predicted a significant decline in zone hydraulic grade line (HGL) across the pressure zone
during peak hour demand conditions, especially to the north of the zone. The C Tank was
predicted to empty during peak periods. As mentioned in Chapter 2, the base elevation of
the C Tank is approximately 8 feet above the zone HGL of 384 ft-msl. This may result in the
need for an additional storage reservoir in the north of the system.
While rehabilitating the Santa Fe I tank would resolve the shortage shortfall anticipated at
build out (excluding Mahr Reservoir), it is most likely not cost effective to connect to the
Santa Fe I tank until Expansion Segment 4C is constructed. As Expansion Segment 4C is
not part of Phase III, as separate storage analysis for Phase III was conducted, which is
summarized in Table 9.16.
As shown in Table 9.16, a storage shortfall of 2.0 MG is anticipated for Phase III when Mahr
Reservoir is not included. Based on the assumption that CMWD would maintain operational
storage within its distribution system under its control, additional storage is recommended
to be placed at the existing Twin D tank site, sized at 2 MG. With this additional storage,
PHD could then be supplied to Zones 550 and 660 from the Twin D storage. At build out, it
is recommended to also rehabilitate the Santa Fe I tank and use this for storage. Hence, a
total of 4.5 MG of new storage is recommended and included in the CIP.
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Alternatively, CMWD can use Mahr Reservoir or equalization basins at Carlsbad WRF to
meet the deficit during Phase III and add storage in build out through rehabilitation of the
Santa Fe I tank. However, to maintain control of storage within CMWD’s distribution
system, the recommendation of this report is to add 2 MG of storage at the Twin D tank site
as a part of Phase III and rehabilitate the Santa Fe I tank as a part of the build out phase.
Table 9.16 Storage Capacity Evaluation for Phase III Recycled Water Master Plan
Carlsbad Municipal Water District
Zone MMD (mgd)
Operational Storage(1,2) (MG)
Short-Term
Emergency Storage(1,3) (MG)
Total
Required Storage (MG)
Existing Storage (MG) Balance (MG)
660 0.6 0.2 0.1 0.3 0.0 -0.3
550 2.9 1.0 0.5 1.5 0.0 -1.5
Subtotal 3.6 1.2 0.6 1.8 0.0 -1.8
Subtotal w/ Mahr 3.6 1.2 0.6 1.8 32.0 +30.2
580 0.4 0.2 0.1 0.2 -0.2
384 6.8 2.2 1.2 3.4 3.5 +0.1
318 0.2 0.1 0.0 0.1 -0.1
Subtotal 7.4 2.4 1.3 3.7 3.5 -0.2
Total w/o Mahr 11.0 3.6 1.9 5.5 3.5 -2.0
Total w/ Mahr 11.0 3.6 1.9 5.5 35.5 +30.0
Notes: (1) Operational and Emergency Storage requirements are based on the evaluation criteria from Chapter 7.
(2) Based on the evaluation criteria, Operational Storage is 33 percent of the MMD. (3) Based on the evaluation criteria, Emergency Storage is 17 percent of the MMD, or four hours.
9.3.12 Pump Station Analysis
This analysis compares the capacity of each existing pump station to the corresponding
built out demands to determine whether additional pumping capacity is required. Table 9.17
presents a summary of this analysis.
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Table 9.17 Ultimate Pump Station Capacity Analysis Recycled Water Master Plan
Carlsbad Municipal Water District
Booster Pumping
Station
Pressure
Zone
MMD
(mgd)
MMD
(gpm)
Required
Capacity
(gpm)
Firm
Capacity
(gpm)
Balance
(gpm)
Bressi PS 660 0.6 448 952 3,000 +2,552
Calavera PS 580 0.4 312 935(1) 1,200 +265
Twin D PS 550, 660 4.8 3,341 3,371 4,500 +1,159
Carlsbad WRF PS(2,3) all 14.0 9,722 9,722 10,000 +278
Notes: (1) No operational storage for daily peaking is included for Calavera PS in Zone 580. A peaking factor of 3.0 was applied.
(2) For reliability purposes it is assumed that this PS needs be able to supply the system wide MMD with Meadowlark WRF out of service. (3) CMWD does not plan for standby pumping capacity at Carlsbad WRF.
As shown in Table 9.17, all pump stations have sufficient pumping capacity to meet the
projected demands. Hence, no pump station expansions are included in the CIP.
Note that as Carlsbad WRF has occasionally been used in the past to serve PHD, if CMWD
maintains the capability for supplying PHD from Carlsbad WRF, additional capacity may be
required. The recommendation of this report is to maintain MMD pumping capacity. Hence,
no pump station expansions are included in the CIP.
9.4 SUMMARY OF FUTURE SYSTEM RECOMMENDATIONS
9.4.1 Distribution System
The recommendations detailed in this chapter are summarized in Table 9.18. Detailed cost
estimates for each of these recommendations are included in the capital improvement
program (CIP), which is presented in Chapter 10.
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Table 9.18 Future System Recommendations
Recycled Water Master Plan Carlsbad Municipal Water District
Phase Description Category Size/Capacity
Phase III Expansion Alignment 2 Pipeline 17,500 feet
Phase III Expansion Alignment 3 Pipeline 8,600 feet
Phase III Expansion Alignment 4A Pipeline 1 vault
Phase III Expansion Alignment 4A Pipeline 700 feet
Phase III Expansion Alignment 4B Pipeline 23,200 feet
Phase III Expansion Alignment 7 Pipeline 2,500 feet
Phase III Expansion Alignment 8 Pipeline 6,500 feet
Phase III Expansion Alignment 9 Pipeline 5,800 feet
Phase III Expansion Alignment 10 Pipeline 3,400 feet
Phase III Expansion Alignment 14 Pipeline 5,900 feet
Phase III Expansion Alignment 15 Pipeline 2,300 feet
Phase III Zone 384 Reservoir Storage 2 MG
Phase III Increase Capacity of Carlsbad WRF Treatment 4 mgd
Build-out Expansion Alignment 1 Pipeline 15,400 feet
Build-out Expansion Alignment 4C Pipeline 63,800 feet
Build-out Expansion Alignment 5 Pipeline 54,200 feet
Build-out Expansion Alignment 6 Pipeline 3,900 feet
Build-out Expansion Alignment 11 Pipeline 25,700 feet
Build-out Expansion Alignment 12 Pipeline 8,100 feet
Build-out Expansion Alignment 13 Pipeline 5,900 feet
Build-out Expansion Alignment 16 Pipeline 1,400 feet
Build-out Expansion Alignment 17 Pipeline 19,000 feet
Build-out Expansion Alignment 18 Pipeline 5,400 feet
Build-out Redundancy Pipeline Carlsbad Village Pipeline 4,200 feet
Build-out Slipline Pipeline to Santa Fe Tank I Pipeline 3,600 feet
Build-out Increase Capacity of Carlsbad WRF Treatment 3 mgd
Build-out Rehabilitate Santa Fe Tank I Storage 2.5 MG
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Chapter 10
CAPITAL IMPROVEMENT PROGRAM
10.1 INTRODUCTION
The purpose of this chapter is to provide the Carlsbad Municipal Water District (CMWD)
with a phased capital improvement program (CIP) that will guide CMWD with the
implementation of recycled water system expansions in an effort to offset potable water
demand requirements as much as possible.
The previous chapter proposed a recommended recycled water system. In this chapter,
cost assumptions are presented, followed by a description of the proposed Phase III and
Build Out systems, and the proposed project phasing. This chapter is concluded with an
estimate of the costs of the recommended CIP.
10.2 COST ESTIMATING ASSUMPTIONS
10.2.1 Scope and Accuracy Range
The cost estimating criteria presented herein develop a consistent methodology for
comparing alternatives. This methodology allows for different alternatives to be evaluated
on the same cost basis.
Cost estimates presented in this master plan are based on the current Engineering and
News Record (ENR) 20 cities cost index of 9,035 published in May 2011. Future
adjustments of cost estimates presented in this report can be estimated by increasing the
estimated capital cost by the ratio of the future ENR to 9,035.
The cost estimates presented in the CIP have been prepared for general master planning
purposes and for guidance in project evaluation and implementation. The actual costs of a
project will depend on actual labor and material costs, competitive market conditions, final
project scope, implementation schedule, and other variable factors such as preliminary
alignment generation, detailed utility surveys, and environmental and local considerations.
The Association for the Advancement of Cost Engineering (AACE) defines an order-of-
magnitude estimate for master plan studies as an approximate estimate made without
detailed engineering data. It is normally expected that an estimate of this type would be
accurate within +50 percent to -30 percent. This section presents the assumptions used in
developing order of magnitude cost estimates for recommended facilities.
The AACE International defines five different class estimate categories as summarized in
Table 10.1.
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Table 10.1 Class Estimates
Recycled Water Master Plan Carlsbad Municipal Water District
Class Status of Design Accuracy Range
Low Side High Side
5 N/A -20% to -50% +30% to +100%
4 1% to 5% -15% to -30% +20% to +50%
3 10% to 40% -10% to -20% +10% to +30%
2 30% to 70% -5% to -15% +5% to +20%
1 80% to 110% -3% to -10% +3% to +15%
5 Rough Order-of-Magnitude Planning Estimate
4 Detailed Planning Level Estimate
3 Project Budget Estimate
2 Detailed Project Control Estimate
1 Bid Check Estimate
Note:
Percentages are based on the construction cost value and not on an incremental subtotal after each percentage category
The budgeting level estimates needed for planning purposes and CIPs are usually based
on Class 5, and as such, the costs developed in this master plan shall be considered
Class 5 estimates, unless noted otherwise. A definition of the five different class estimates
is described below.
Class 5. This estimate is considered as rough order-of-magnitude estimate. It is usually
prepared based on limited information, where little more than proposed facility
type, its location, and the capacity are known. Strategic planning purposes
include, but are not limited to, market studies, assessment of viability, evaluation
of alternate schemes, project screening, location and evaluation of resource
needs and budgeting, and long-range capital planning. Examples of estimating
methods used would be cost/capacity curves and factors, scale-up factors, and
parametric and modeling techniques. Little time is expended in the development of
this estimate. The typical expected accuracy range for this class estimate is -20 to
-50 percent on the low side and +30 to +100 percent on the high side.
Class 4. This estimate is prepared based on information where the preliminary engineering
is 1 to 5 percent complete. Detailed strategic planning, business development,
project screening, alternative scheme analysis, confirmation of economic and/or
technical feasibility, and preliminary budget approval are needed to proceed with
this class estimate. Examples of estimating methods used would include
equipment and/or system process factors, scale-up factors, as well as parametric
and modeling techniques. This estimate requires more time to develop. The
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typical expected accuracy range for this class estimate is -15 to -30 percent on the
low side and +20 to +50 percent on the high side.
A Class 4 estimate may also be justified by the methods presented for this cost
evaluation if suitable definitions of project components, individual consideration of
special project components/conditions, and independent cost verifications are
conducted. Commensurate reductions in project contingencies should also be
considered for the Class 4 estimate.
The following class estimates are typically used during the preliminary and final design
stages of a project and are not applicable to estimates developed using this estimating
guide. They are described in this report for information and consistency. These estimate
classes include Class 3, Class 2, and Class 1:
Class 3. This estimate is prepared to form the basis for the project authorization, and/or
funding. Typically, engineering is 10 to 40 percent complete, and would comprise
process flow diagrams, preliminary piping runs for major processes, facility layout
drawings, and complete process and facility equipment lists. This estimate
becomes the project control or project budget estimate until more detailed
estimates are completed. Examples of methods used would be a high degree of
detailed unit cost, and quantity takeoffs for major processes. Factoring and/or
scale-up factors can be used for less significant or support areas of the project.
This estimate requires a great deal of time to prepare, where actual equipment
and processes have been designed. The typical expected accuracy range for this
class estimate is -10 to -20 percent on the low side, and +10 to +30 percent on the
high side.
Class 2. This estimate is prepared to form a detailed control baseline for the project.
Typically, engineering is 30 to 70 percent complete, and would comprise process
flow diagrams, piping and instrument runs for all processes, final facility layout
drawings, complete process and facility equipment lists, single-line diagrams for
electrical components, and schedules. This estimate becomes the detailed project
control estimate. Examples of methods used include a high degree of
deterministic estimating, as well as detailed quantity takeoffs for all facility
processes and/or systems, with little factoring and/or scale-up factors used,
except for minor project support areas. This estimate usually becomes the final
estimate and requires a great deal of line-item information, which can take
significant time to prepare. The typical expected accuracy ranges for this class
estimate are -5 to -15 percent on the low side and +5 to +20 percent on the high
side.
Class 1. This estimate is prepared to confirm the control baseline for the project. Typically,
engineering is 80 to 100 percent complete, which comprises virtually all
engineering and design documentation of the project, and complete project
execution and commissioning plans. This estimate becomes the final control
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baseline of the project. Examples of methods used are the highest degree of
deterministic estimating, with very detailed quantity takeoffs for all facility
processes and/or systems of the project. This type of estimate usually becomes
the bid check estimate and can require the most effort to create. The typical
expected accuracy ranges for this class estimate are -3 to -10 percent on the low
side and +3 to +15 percent on the high side.
All classes of cost estimates described, and any resulting conclusions on project financial or
economic feasibility or funding requirements, are prepared for guidance in project
evaluation and implementation. The final costs of the project, and resulting feasibility, will
depend on actual labor and material costs, competitive market conditions, actual site
conditions, final project scope, implementation schedule, continuity of personnel and
engineering, and other variable factors. Therefore, the final project costs will vary from the
estimate developed using the information in this master plan. Because of these factors,
project feasibility, cost-benefit ratios, risks, and funding needs must be carefully reviewed
prior to making specific financial decisions or establishing project budgets to help ensure
proper project evaluation and adequate funding.
This evaluation is concerned only with estimates at the planning and conceptual phase of
the projects for CMWD. Therefore, only Class 5 estimates have been developed. For the
development of the CIP, a construction cost contingency and other markups will be applied
consistent with Table 10.2. The markups are intended to account for costs of engineering,
design, administration, and construction management.
10.2.2 Markups and Contingency
The cost estimates are based on current perceptions of conditions at the project locations.
These estimates reflect Carollo’s professional opinion of costs at this time and are subject
to change as the project details are defined. Carollo has no control over variances in the
cost of labor, materials, equipment, services provided by others, contractor’s methods of
determining prices, competitive bidding, or market conditions, practices, or bidding
strategies. Carollo cannot, and does not, warrant or guarantee that proposals, bids, or
actual construction costs will not vary for the costs presented as shown.
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Table 10.2 General Cost Estimating Assumptions
Recycled Water Master Plan Carlsbad Municipal Water District
Description
Percent of
Construction Cost
Construction Cost 100.0%
Construction Cost Contingency 20.0%
Construction Cost + Contingency 120.0%
Engineering and Design 10.0%
Project Administration 2.5%
Construction Management 5.0%
Construction Inspection 10.0%
Total Markups 127.5%
Total Project Cost(1) 153.0%
Note:
(1) Percentages are based on the construction cost value and not on an incremental subtotal after each category. Total Project Cost = Construction Cost + Contingency x Total Markups.
10.2.3 Unit Construction Costs
The construction cost estimates presented in this report are based on the unit construction
costs listed in Table 10.3. Construction costs for recycled water system pipelines include
pipe material, valves, appurtenances, excavation, installation, bedding material, backfill
material, transport, and paving where applicable. The costs of acquiring easements for
pipeline construction are not included in the estimates presented in this report.
Table 10.3 Unit Construction Cost
Recycled Water Master Plan Carlsbad Municipal Water District
Category Unit Construction Cost
Pipelines $/lineal ft
4-inch diameter 100
6-inch diameter 110
8-inch diameter 120
12-inch diameter 150
16-inch diameter 290
18-inch diameter 350
20-inch diameter 400
24-inch diameter 500
30-inch diameter 650
36-inch diameter 750
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Table 10.3 Unit Construction Cost
Recycled Water Master Plan Carlsbad Municipal Water District
Category Unit Construction Cost
Special Pipeline Construction Markup (%) or $/lineal ft
Slip-lining(1) (8" into a 21") $85 /lineal ft
Booster Pumping Stations – New Construction $/hp
< 100 hp $6,000
100 to < 500 hp $4,500
500 hp and greater $3,500
Storage $/gallon
< 1 MG $2.00
1 to < 2 MG $1.75
2 to < 5 MG $1.50
5 MG and greater $1.25
Miscellaneous $/unit
Customer Laterals $4,000 $/lateral
Enclosure Structures $300 $/sf
PRV (in pre-existing vault) $50,000 $/station
Note:
(1) The unit cost for sliplining was developed based on the elevation differences, diameter, and length of the TAP connection. It is assumed that the unit construction costs would be similar for the other projects requiring sliplining of existing pipelines.
For booster pumping stations (PS), unit costs are included based on the required
horsepower assuming the project involves a new PS requiring new piping and all
associated appurtenances. If a PS project only requires the replacement or addition of a
pump to an existing PS, the unit costs will be evaluated on a per site basis at that time. Unit
costs for PSs are estimated per horsepower of design size.
10.2.4 Excluded Costs
There are several other components that may be needed to support the development of
major water supply facilities. Since most of these items are unique and project specific, they
should be applied on a project-by-project basis. Therefore, no unit costs were included in
Table 10.3 for the following items:
• Land acquisition. Cost for purchasing land or right of way are not included due to
variability of real estate market conditions.
• Power transmission lines. The cost of these to support a major pumping or
treatment is often on a shared cost basis with the power utility.
• Maintenance roads. If pipelines are installed in remote areas, maintenance roads
are sometimes required to access the facilities.
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• Overall program management. If the sheer magnitude of the capital cost program
exceeds the capacity of City of Carlsbad staff to manage all of the work, then the
services of a program management team may be required.
• Public information program. Depending on the relative public acceptability of a
major water facility or a group of facilities, there may be a need for a public
information program, which could take many different shapes.
• Customer retrofits. Retrofit costs are associated with separating the customer’s
existing potable water system from a new recycled water system. An example would
be a park where restroom and drinking fountain water supply pipes would need to be
isolated from an existing irrigation system. Additional costs include posting signage,
which identifies where recycled water is being used. Customer retrofits are one-time
costs and are dependent upon the complexity of existing irrigation systems at each
individual site. This cost estimate excludes cost of customer retrofits.
• Foundation requirements. Foundation reinforcement or support requirements are
very site specific with regard to necessary method and type, and a geotechnical study
is typically needed to determine such requirements. These costs, therefore, have not
been included in any of the unit cost curves.
• Other costs. These costs may be necessary on some projects and could include
environmental mitigation and permitting costs; special legal, administrative, or
financial assistance; easements or rights-of-way and land acquisition costs; and
expediting costs, such as separate material procurement contracts. These other costs
typically range from 5 to 15 percent of construction cost.
10.3 SUMMARY OF RECOMMENDATIONS
This section summarizes the projects recommended in Chapter 8 (Existing System
Analysis) and Chapter 9 (Future System Analysis). The detailed cost estimate for each
component of each project is presented followed by a summary of the cost estimate data by
project type and phase.
10.3.1 Project Cost Estimates
Table 10.4 presents the detailed cost estimate for each component of the projects based on
the recommended projects and quantities described in Chapters 8 and 9 and the unit costs
presented in Table 10.3.
10-8 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 10 Table 10.4 Detailed Project List
Recycled Water Master Plan Carlsbad Municipal Water District Project ID Category Description Planning Phase Size Unit Capacity Unit Cost Construction Cost Capital Cost P01 Pipeline Expansion Alignment 1 Build-out 3,100 ft 4 in 100 $ per lineal ft $310,000 $475,000 P02 Pipeline Expansion Alignment 1 Build-out 5,200 ft 6 in 110 $ per lineal ft $575,000 $880,000
P03 Pipeline Expansion Alignment 1 Build-out 7,100 ft 8 in 120 $ per lineal ft $855,000 $1,310,000 P04 Pipeline Expansion Alignment 1 Build-out 58 meters 4,000 $ per meter $235,000 $360,000 P05 Pipeline Expansion Alignment 2 Phase III 1,300 ft 6 in 110 $ per lineal ft $145,000 $225,000 P06 Pipeline Expansion Alignment 2 Phase III 3,700 ft 8 in 120 $ per lineal ft $445,000 $685,000 P07 Pipeline Expansion Alignment 2 Phase III 3,900 ft 12 in 150 $ per lineal ft $585,000 $900,000 P08 Pipeline Expansion Alignment 2 Phase III 200 ft 16 in 290 $ per lineal ft $60,000 $95,000 P09 Pipeline Expansion Alignment 2 Phase III 4,900 ft 20 in 400 $ per lineal ft $1,960,000 $3,000,000 P10 Pipeline Expansion Alignment 2 Phase III 3,500 ft 24 in 500 $ per lineal ft $1,750,000 $2,680,000 P11 Pipeline Expansion Alignment 2 Phase III 18 meters 4,000 $ per meter $75,000 $115,000 P12 Pipeline Expansion Alignment 3 Phase III 3,000 ft 6 in 110 $ per lineal ft $330,000 $505,000 P13 Pipeline Expansion Alignment 3 Phase III 1,400 ft 8 in 120 $ per lineal ft $170,000 $265,000 P14 Pipeline Expansion Alignment 3 Phase III 4,200 ft 12 in 150 $ per lineal ft $630,000 $965,000 P15 Pipeline Expansion Alignment 3 Phase III 2 meters 4,000 $ per meter $10,000 $20,000 P16 Pipeline Expansion Alignment 4A Phase III 2 interc. 100,000 $ per conn. $200,000 $310,000 P17 Pipeline Expansion Alignment 4A Phase III 700 ft 12 in 150 $ per lineal ft $105,000 $165,000 P18 Pipeline Expansion Alignment 4A Phase III 1 meters 4,000 $ per meter $5,000 $10,000 P19 Pipeline Expansion Alignment 4B Phase III 500 ft 4 in 100 $ per lineal ft $50,000 $80,000 P20 Pipeline Expansion Alignment 4B Phase III 4,000 ft 6 in 110 $ per lineal ft $440,000 $675,000 P21 Pipeline Expansion Alignment 4B Phase III 5,400 ft 8 in 120 $ per lineal ft $650,000 $995,000 P22 Pipeline Expansion Alignment 4B Phase III 11,700 ft 12 in 150 $ per lineal ft $1,755,000 $2,690,000 P23 Pipeline Expansion Alignment 4B Phase III 1,600 ft 16 in 290 $ per lineal ft $465,000 $715,000 P24 Pipeline Expansion Alignment 4B Phase III 9 meters 4,000 $ per meter $40,000 $65,000 P25 Pipeline Expansion Alignment 4C Build-out 2,600 ft 4 in 100 $ per lineal ft $260,000 $400,000 P26 Pipeline Expansion Alignment 4C Build-out 22,600 ft 6 in 110 $ per lineal ft $2,490,000 $3,810,000 P27 Pipeline Expansion Alignment 4C Build-out 11,400 ft 8 in 120 $ per lineal ft $1,370,000 $2,100,000
July 2011 10-9 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 10 Table 10.4 Detailed Project List
Recycled Water Master Plan Carlsbad Municipal Water District
P28 Pipeline Expansion Alignment 4C Build-out 27,200 ft 12 in 150 $ per lineal ft $4,080,000 $6,245,000 P29 Pipeline Expansion Alignment 4C Build-out 369 meters 4,000 $ per meter $1,480,000 $2,265,000 P30 Pipeline Expansion Alignment 5 Build-out 7,000 ft 4 in 100 $ per lineal ft $700,000 $1,075,000 P31 Pipeline Expansion Alignment 5 Build-out 9,300 ft 6 in 110 $ per lineal ft $1,025,000 $1,570,000 P32 Pipeline Expansion Alignment 5 Build-out 33,700 ft 8 in 120 $ per lineal ft $4,045,000 $6,190,000 P33 Pipeline Expansion Alignment 5 Build-out 4,200 ft 12 in 150 $ per lineal ft $630,000 $965,000 P34 Pipeline Expansion Alignment 5 Build-out 31 meters 4,000 $ per meter $125,000 $195,000 P35 Pipeline Expansion Alignment 6 Build-out 2,100 ft 6 in 110 $ per lineal ft $235,000 $360,000 P36 Pipeline Expansion Alignment 6 Build-out 1,800 ft 8 in 120 $ per lineal ft $220,000 $340,000 P37 Pipeline Expansion Alignment 6 Build-out 3 meters 4,000 $ per meter $15,000 $25,000 P38 Pipeline Expansion Alignment 7 Phase III 2,500 ft 8 in 120 $ per lineal ft $300,000 $460,000 P39 Pipeline Expansion Alignment 8 Phase III 6,500 ft 12 in 150 $ per lineal ft $975,000 $1,495,000 P40 Pipeline Expansion Alignment 8 Phase III 1 meters 4,000 $ per meter $5,000 $10,000 P41 Pipeline Expansion Alignment 9 Phase III 1,600 ft 6 in 110 $ per lineal ft $180,000 $280,000 P42 Pipeline Expansion Alignment 9 Phase III 4,200 ft 8 in 120 $ per lineal ft $505,000 $775,000 P43 Pipeline Expansion Alignment 9 Phase III 4 meters 4,000 $ per meter $20,000 $35,000 P44 Pipeline Expansion Alignment 10 Phase III 3,400 ft 8 in 120 $ per lineal ft $410,000 $630,000 P45 Pipeline Expansion Alignment 10 Phase III 2 meters 4,000 $ per meter $10,000 $20,000 P46 Pipeline Expansion Alignment 11 Build-out 2,700 ft 4 in 100 $ per lineal ft $270,000 $415,000 P47 Pipeline Expansion Alignment 11 Build-out 7,500 ft 6 in 110 $ per lineal ft $825,000 $1,265,000 P48 Pipeline Expansion Alignment 11 Build-out 10,400 ft 8 in 120 $ per lineal ft $1,250,000 $1,915,000 P49 Pipeline Expansion Alignment 11 Build-out 5,100 ft 12 in 150 $ per lineal ft $765,000 $1,175,000 P50 Pipeline Expansion Alignment 11 Build-out 29 meters 4,000 $ per meter $120,000 $185,000 P51 Pipeline Expansion Alignment 12 Build-out 500 ft 4 in 100 $ per lineal ft $50,000 $80,000 P52 Pipeline Expansion Alignment 12 Build-out 2,500 ft 6 in 110 $ per lineal ft $275,000 $425,000 P53 Pipeline Expansion Alignment 12 Build-out 5,100 ft 8 in 120 $ per lineal ft $615,000 $945,000 P54 Pipeline Expansion Alignment 12 Build-out 14 meters 4,000 $ per meter $60,000 $95,000 P55 Pipeline Expansion Alignment 13 Build-out 5,900 ft 8 in 120 $ per lineal ft $710,000 $1,090,000 P56 Pipeline Expansion Alignment 13 Build-out 8 meters 4,000 $ per meter $35,000 $55,000 P57 Pipeline Expansion Alignment 14 Phase III 1,400 ft 4 in 100 $ per lineal ft $140,000 $215,000 P58 Pipeline Expansion Alignment 14 Phase III 1,000 ft 6 in 110 $ per lineal ft $110,000 $170,000
10-10 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 10 Table 10.4 Detailed Project List
Recycled Water Master Plan Carlsbad Municipal Water District
P59 Pipeline Expansion Alignment 14 Phase III 3,500 ft 8 in 120 $ per lineal ft $420,000 $645,000 P60 Pipeline Expansion Alignment 14 Phase III 6 meters 4,000 $ per meter $25,000 $40,000 P61 Pipeline Expansion Alignment 15 Phase III 1,000 ft 4 in 100 $ per lineal ft $100,000 $155,000 P62 Pipeline Expansion Alignment 15 Phase III 1,300 ft 6 in 110 $ per lineal ft $145,000 $225,000 P63 Pipeline Expansion Alignment 15 Phase III 9 meters 4,000 $ per meter $40,000 $65,000 P64 Pipeline Expansion Alignment 16 Build-out 1,400 ft 6 in 110 $ per lineal ft $155,000 $240,000 P65 Pipeline Expansion Alignment 16 Build-out 3 meters 4,000 $ per meter $15,000 $25,000 P66 Pipeline Expansion Alignment 17 Build-out 1,800 ft 4 in 100 $ per lineal ft $180,000 $280,000 P67 Pipeline Expansion Alignment 17 Build-out 13,200 ft 6 in 110 $ per lineal ft $1,455,000 $2,230,000 P68 Pipeline Expansion Alignment 17 Build-out 4,000 ft 8 in 120 $ per lineal ft $480,000 $735,000 P69 Pipeline Expansion Alignment 17 Build-out 26 meters 4,000 $ per meter $105,000 $165,000 P70 Pipeline Expansion Alignment 18 Build-out 4,700 ft 6 in 110 $ per lineal ft $520,000 $800,000 P71 Pipeline Expansion Alignment 18 Build-out 700 ft 8 in 120 $ per lineal ft $85,000 $135,000 P72 Pipeline Expansion Alignment 18 Build-out 17 meters 4,000 $ per meter $70,000 $110,000 P73 Pipeline Retrofit Customers near Existing System Phase III 30 meters 4,000 $ per meter $120,000 $185,000
P74 Pipeline Redundancy Looping Build-out 4,200 ft 12 in 150 $ per lineal ft $630,000 $965,000 P75 Pipeline Customers Near Existing System Phase III 17 meters 4,000 $ per meter $70,000 $110,000
P76 Storage C Tank Chlorination and Mixing System Existing $75,000 $115,000
P77 Storage Zone 384 Reservoir Phase III 2.0 MG 1,500,000 $ per MG $3,000,000 $4,590,000 P78 Pipeline Pipeline to Santa Fe Tank I Build-out 3,600 ft 12 in 150 $ per lineal ft $540,000 $830,000 P79 Storage Rehabilitate Santa Fe Tank I Build-out 2.5 MG 1,500,000 $ per MG $3,750,000 $5,740,000 P80 Treatment Increase Capacity of Carlsbad WRF Phase III 4.0 mgd separate estimate $5,490,000 $7,000,000
P81 Treatment Increase Capacity of Carlsbad WRF Build-out 3.0 mgd separate estimate $4,300,000 $5,500,000
Total $56,180,000 $83,680,000
January 2012 10-11 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 10
As shown in Table 10.4, the total estimated construction cost of all identified projects is
$56,180,000, and the corresponding capital cost with the additional markups and
contingencies from Table 10.2 is $83,680,000.
While most projects listed in Table 10.4 are based on the unit costs presented in
Table 10.3, separate estimates were developed for the increases in treatment plant
capacity (Project ID P80 and P81) and are included in Appendix B. Additional lump sum
costs were used for the connection to the failsafe pipeline (Project ID P16) and the C Tank
Chlorination and Mixing System (Project ID P76).
For conservative planning purposes, unit costs for the rehabilitation of the Santa Fe Tank
(Project ID P79) were assumed to be similar to new construction.
Project Phasing
Existing system recommendations, summarized in Chapter 8, are discussed separately as
an existing phase. It is anticipated that these improvements would be implemented at the
same time as Phase III. As discussed in Chapter 9, the system expansions are divided into
two 10-year phases, Phase III and the Build-out Phase. The system expansions of the
recommended system are described by phase below.
Existing: The existing system analysis consisted of one recommendation - a chlorination
system for the C Tank. The capital cost for this recommendation is estimated as $0.1 M.
Phase III (2011-2020): Phase III includes the most feasible alignments as described in
Chapter 9. This would expand CMWD’s recycled water system to the north area of
Carlsbad and begin initial expansion into the neighboring agency through wholesale service
to Shadowridge Golf Course. The overall system cost of these expansions is estimated at
$32.3 M; and therefore would require a further increase in recycled water funds, either
generated by rates and/or outside funding. It is assumed that the opportunities for funding
would increase in the next decade to accommodate the increase in annual recycled water
system expansion costs.
Build-out Phase (2021-2030): The Build-out Phase includes the expansion alignments not
included in Phase III, as well as the backbone pipelines to the potential new developments
with uncertain timing. The overall system cost of these build out expansions is estimated at
$51.3 M, which is about double the cost of the Phase III expansion. Hence, a greater level
of revenue generation from rates and outside funding would be required to implement these
projects.
10-12 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 10
10.4 CAPITAL IMPROVEMENT PROGRAM
10.4.1 CIP by Planning Phase
As discussed previously, the CIP is divided into two phases. The first phase consists of the
projects to be implemented as a part of the Phase III improvement program, while the
second phase consists of the remaining projects anticipated through build-out of the
recycled water system. Table 10.5 summarizes the breakdown of costs for each of the two
phases (shown in million dollars).
Table 10.5 Capital Cost by Planning Phase and Project Type Recycled Water Master Plan
Carlsbad Municipal Water District
Project Type Existing Phase III Build-out Phase Total
Pipelines $0.0 $20.7 $40.1 $60.7
Treatment $0.0 $7.0 $5.5 $12.5
Storage $0.1 $4.6 $5.7 $10.4
Total $0.1 $32.3 $51.3 $83.7
Note: (1) Capital Costs are based on the cost assumptions discussed in Section 10.2. Detailed information for each
project can be found in Table 10.4.
As shown in Table 10.5, the capital cost for Phase III is estimated at $32.3 M while the
capital cost associated with the Build-out Phase is estimated at $51.3 M. Figure 10.1
presents the capital costs for each identified phase.
$0.1
$32.3
$51.3
$0
$10
$20
$30
$40
$50
$60
Existing Phase III Build-out PhaseCapital Cost($ million)
Figure 10.1 Capital Cost by Phase
The locations of the projects included in Phase III and the Build-out Phase are shown on
Figure 10.2.
"C" Tank
Carlsbad WRF
Gafner WRP
Mahr Reservoir
Meadowlark WRF
Agua HediondaLagoon
Twin "D" TanksCami
n
o
R
e
al
E lm A veMarron Rd
C
arls
b
a
d Blv
d
Hig
hla
n
d Dr
A londra W ayPaseo Nort
eCollege BlvdPalomar Airport
Aviara Pkwy El Fuerte StCosta AvePoinsettia LnTam arack AveCannon Rd
Calle BarcelonaRanch o Santa FeCalavera PS
CWRF PS
Bressi PS
"D" Tank PSPacific Ocean
Encinitas
Batiquitos Lagoon
Buena VistaLagoon Oceanside
Shadowridge WRP
LakeCalavera
Corintia Meter
OMWDMeter
8"
20
San Marcos
Vista
Encinitas
Oceanside
3
17
5
8
2
7
6
1
9
11
11
13
12
10
14
16
18
4
15
2
0
"8"16"1
2
"
8"
8"
8
"
8
"
8"
8"8"
8
"8"8"8"8"8"8"8"8"8 "
8
"
8"8"8"
8"8"
8"8"
8
"
8"
8"8"8"8"8"8"8"8 "
8"8"8"
8
"
8"
8"
8"8"8"8 "
8 "
8"8"8"8"8"8"8"
8"
8
"
8"8"12"8"
8"20"8"8"8"
1
2"
8"
8"8"8
"
8"
8"
8"8"8"8 "
C017
C177
C179
C170
C169
C166
C178
C165
C164 C163
C161
C064
C031
C158
C126
C116 C157
C156
C155
C153
C152 C151
C149
C148C146
C145C144
C143 C102
C123
C103
C101
C105
C111
C114
C129
C134
C139C121
C124
C115
C113
C128
C108C130
C127 C118
C122
C131C120
C133
C107
C109
C140
C141
C104
C098
C100
C005
C001
C008
C071
C062
C087
C010
C088
C041
C068
C051
C063
C037
C078
C018C047
C046
C003
C019
C013
C027
C004
C021
C022
C007
C016
C036 C015
C006
Legend
Recycled Water FacilitiesInactive WRP
Pump StationPRV
Meter
WRF
Tank
Reservoir
Potential Expansion SegmentsPhase IIIBuild OutDevelopment AreasAlready ConstructedExisting Recycled Water PipelinesDiameterLess than 6"6" to 8"10" to 14"16" and largerFuture DevelopmentResidential All OthersDevelopment not anticipated toutilize Recycled Water (Small Parcel)OtherFreewaysMajor RoadsLocal StreetsRailroadsWater BodyCarlsbad Municipal Water District BoundaryCarlsbad City LimitsSan Diego County
0 5,000 10,000Feet
Figure 10.2Phasing of Potential Expansion SegmentsRecycled Water Master PlanCarlsbad Municipal Water DistrictFILENAME: c:\pw_working\projectwise\lwang\d0102644\Figure_10_2-Phasing of Potential Expansion Segments.mxdDATE: 1/14/2011
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10.4.2 CIP by Project Type
As shown in Table 10.5, pipelines represent the largest component of the total capital cost
at about $61 M. Treatment and storage are similar in cost, at approximately $11 M and
$10 M, respectively. Figure 10.3 presents the capital cost by project type graphically.
Pipelines $60.7M
73%
Treatment $12.5M
15%
Storage
$10.4M 12%
Total Build Out CIP
$83.7 million
Figure 10.3 Capital Cost by Project Type
10.4.3 Escalated CIP
As discussed in Chapter 9, it is anticipated that completing the infrastructure to support
Phase III will require approximately 5 years with an additional 5 years to connect all the
customers to the distribution system. It is assumed that the Build-out Phase will follow a
similar schedule. Based on this schedule, the approximate timeline for implementation of
the two phases are shown in Table 10.6.
Table 10.6 Timeline of Phasing
Recycled Water Master Plan Carlsbad Municipal Water District
Phase Design and Construction of Infrastructure Connection of Customers
Phase III 2011 – 2015 2015 – 2020
Build-out 2021 - 2025 2025 – 2030
10-16 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 10
The estimated escalated capital project costs are shown in Table 10.7. Cost escalation is
calculated with a 3-percent inflation rate and uses the mid-year of each estimated phase of
implementation. It is assumed that the existing system improvements would be
incorporated into construction of Phase III. The mid-year of Phase III is 2013 while the
mid-year of the Build-out Phase is 2023. A base year of 2010 was used to calculate cost
escalation.
Table 10.7 Escalated CIP by Planning Phase
Recycled Water Master Plan Carlsbad Municipal Water District
Phase Capital Cost Escalated Capital Cost
Existing $0.1 $0.2
Phase III $32.3 $35.3
Build-out $51.3 $75.4
Total $83.7 $110.9
Note:
(1) Calculation of escalated cost assumes a baseline year of 2010 and an inflation rate of 3 percent.
Figure 10.4 depicts the escalated capital cost as compared to the present day cost
graphically.
$0.1
$32.3
$51.3
$0.2
$35.3
$75.4
$0
$10
$20
$30
$40
$50
$60
$70
$80
$90
Existing Phase III Build-out PhaseCapital Cost($ million)Capital Cost Escalated Capital Cost
Figure 10.4 Escalated Capital Cost
January 2012 10-17 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 10
As shown in Figure 10.4, the escalated capital cost figures more significantly into the
Build-out Phase than Phase III. The anticipated unit cost of recycled water for each
expansion phase is compared with the projected cost of imported water in Figure 10.5. As
shown, the average unit cost for each phase is below the projected imported water costs for
the same time period. Unit costs were calculated using annualized capital cost based on a
depreciation period of 50 years and six (6) percent interest.
$0
$500
$1,000
$1,500
$2,000
$2,500
2010 2015 2020 2025 2030Unit Cost ($/af)Year
Treatment and Storage Conveyance
Treated Imported Water Cost (SDCWA)Projection
Recycled Water System Expansion
Phase III
Build Out
Figure 10.5 Comparison of Unit Costs to Imported Water
Based on the potable water cost curve presented in Figure 10.5, it can be concluded that
the expansion of CMWD’s recycled water system in both Phase III and through Build Out
conditions is a cost-effective alternative to potable water supply. In addition to the cost
benefit, recycled water provides increased supply reliability, especially during drought
periods, and allows CMWD to remain more in control of the overall water supply cost for its
customers.
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