HomeMy WebLinkAbout1979-08-21; City Council; 5577-3; Encina facility capacity and EDU flow ratey-V •/•'
CITY OF CARLSBAD
0 _o_ Initial: ^.^
AGENDA BILL NO • ^^^.^^L^^^^t *^3__ Dept. Hea/£
DATE: August 21, 1979 C. Atty
DEPARTMENT: Public Works C. Mgr.
SUBJECT: ENCINA WATER POLLUTION CONTROL FACILITY CAPACITY AND EDU FLOW RATE
STATEMENT OF THE MATTER
Council has requested that staff report from time to time regarding our use of capacity
rights at the Encina Water Pollution Control Facility. The effective management of
Encina treatment capacity requires the analyses of such items as flow rate per equivalent
dwelling unit (EDU), wet weather flows, vacancy rates, litigation, etc.
The attached staff report analyzes pertinent factors as well as several policy choices
available to the City Council. Should the Council concur with staff's recommendations,
the remaining capacity at Encina will be assigned to the following categories in the
amounts indicated: . Fn[,
Available for allocation (second phase) 1,312.91
Available for City Capital Improvement Projects and
failing septic systems 101.67
Grove litigation settlement 660.98
Available for projects of benefit to community 270.00
EXHIBITS
Staff report dated August 8, 1979 from the Public Works Administrator
Resolution No.
RECOMMENDATION
That City Council adopt Resolution No.*S"9o7'changing the City's EDU flow rate from 253
gallons per day to 246 gallons per day; and
That Council, by minute motion, adopt as City policy that, for purposes of determining
available sewage treatment capacity in the City service area, staff use a vacancy factor
of 3$; and
That Council, by minute motion, determine the number of EDUs to make available for second
pnase a I location; and
That Council, by minute motion, indicate their intent to use the Encinitas lease capacity
and reserve 101.67 EDUs for City capital projects and failing septic systems and reserve
270 EDUs for projects deemed by Council as being of benefit to the community.
AGENDA BILL NO. 5577 - Supplement #3 Page 2
Council Action:
8-21-79 Council adopted Resolution 5907, determining the number of
gallons of sewage equal to one equivalent dwelling unit and
adopting it as a regulation pursuant to Section 13.08.081(f)
of the Carlsbad Municipal Code; and
by minute motion, Council adopted as City policy, for purposes
of determining available sewage treatment capacity in the
City service area, that a vacancy factor of 3% be used.
Council determined that further action be delayed until the
report on the Second Phase Sewer Allocation is returned to
Counci 1.
MEMORANDUM
TO: City Manager
FROM: Public Works Administrator
DATE: August 8, 1979
SUBJECT: UPDATE ON SEWER PLANT CAPACITY AND EDU FLOW RATE
You have asked me to review and update my October 12, 1978 report on capacity at
Encina and to verify the accuracy of our flow rate of 253 gallons per day per
equivalent dwelling unit (EDU).
AVAILABLE CAPACITY
Our present capacity at the Encina Water Pollution Control Facility is 3,430,000
gallons per day (3.43 MGD). In addition to this, we have leased 75,000 gallons per
day from the Encinitas Sanitary District and may, in conjunction with settlement of
the Grove lawsuit, lease 56,672 gallons per day capacity from the Vista Sanitation
District. The Encinitas lease expires on September 30, 1982. The Vista lease ex-
pires upon completion of the Encina Phase III expansion project which is estimated
as being sometime within the first half of 1982.
In summary, we own, have leased, or are about to lease a total of 3,561,672 gallons
per day capacity.
WHAT IS COMMITTED; WHAT IS USED
Exhibit "A" is a chart containing flow and issued permit information from the month-
ly Encina JAC report. In order to use this information to determine how we are
using our capacity, we must estimate how many of the issued permits are actually
"on-line and flowing." This calculation accounts for periods when residences may
not be occupied, when industrial facilities are shut down for maintenance, when
stores or other commercial spaces are vacant. It also accounts for units which are
still under construction. In the previous report (October 12, 1978) and in this
report, the "on-line and flowing" figure is arrived at by multiplying the issued
permits by a percentage factor which represents our best estimate of on-line con-
nections. The difference between the percentage used and 100% represents those
issued permits which are under construction plus those which may be vacant at that
point in time. You will notice that the percentage used in recent months is higher
than that used in 1977 and 1978. This reflects the reality of the moratorium in
that most construction from pre-moratori urn permits has been completed.
Once the number of outstanding permits "on-line and flowing" is determined, we can
calculate the average flow rate per EDU.
In my October 12, 1978 report, it was necessary to go through a complex series of
calculations to determine the impact of wet weather flow for an average year. This
was necessary because the only reliable flow data was for an extremely wet year.
This last twelve-month period reflects the impact of a more normal rain season.
Use of the adjusted flow rates includes the impact of infiltration and inflow due
to wet weather and therefore may be used without further interpretation.
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POLICY DECISIONS
There are three basic policy decisions that must be made before we can determine
the number of EDUs available for allocation. The first decision is whether to
change the EDU flow rate or not. The second decision is whether to make allowance
for a vacancy factor or not. The third decision is whether to commit the Encinitas
leased capacity or not.
EDU Flow Rate
Using adjusted EDU flow rate data for the past twelve months gives an average flow
rate per EDU of 245.8 gallons per day. I suggest we use 246 GPP as the new flow
rate per EDU.
Using this recommended figure, our owned capacity of 3,430,000 gallons per day
would yield 13,943 EDUs. This is an increase of 372 EDUs over the previously used
13,571.
Vacancy Factor
Earlier in this report there was some discussion concerning percentage of issued
permits "on-line and flowing." The difference between 100% and the percentage of
"on-line and flowing" can be considered, for purposes of discussion, to be the va-
cancy factor. This is the number of units not contributing to sewage flow because
they are vacant residential units, industrial facilities shut down for maintenance,
stores or other commercial spaces that are vacant or they are units that are still
under construction.
At the present time, the vacancy factory's estimated to be 7%. This figure is
broken into*under construction"(4%) and"vacant"(3%). If the Council is willing
to make the prudent assumption that there will never be less than 3% of total out-
standing permits vacant, they can make the further policy determination that up
to 103% of our total capacity can be committed without exceeding our legal capacity
limits. This additional 3% equals 102,900 gallons per day. Using the recommended
flow rate of 246 gallons per day/EDU, this equates to an additional 418 EDUs.
Encinitas Capacity
As previously mentioned, Council had determined to hold the Encinitas capacity in
reserve because of concerns relating to the expiration date of the lease. Because
of the accelerated construction schedule for Encina Phase III, Council may wish to
reconsider their prior decision. Available capacity from the Encinitas lease totals
305 EDUs (75,000 * 246).
Potential Uses
City projects/septic tanks - The City Engineer, in a memo dated September 8, 1978,
outlined a list of potential City projects that could require sewer capacity. This
list totaled 151 EDUs. He also mentioned the need for a reserve to handle failed
septic systems. Council acted to set aside 75 EDUs to meet this need. As of this
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date, there are 66.67 EDUs remaining in this allotment. The list in the Septem-
ber 8, 1978 memo has been reviewed in light of Council's "Paired Weighting Exer-
cise," the reduced availability of capital construction funds and the projected
completion time for Encina Phase III. It is my opinion that the City Engineer's
previous list can be reduced to a total of 90 EDUs that may need to be supplied
from present capacity. To this must be added some capacity for failing septic sys-
tems. If Council considers using the Encinitas capacity, I would recommend assign-
ing an additional 35 EDUs to the present capital program/septic failure reserve.
Projects of special benefit to the community - From time to time the City Council
is faced with the problem of responding to the needs of major industrial firms to
enlarge existing facilities or construct new facilities to allow for relocation to
Carlsbad. Council may also face the needs of a proposed cultural or community fa-
cility that they would like to see built to meet the needs of our citizens. At
the present time, there is no way that Council can respond to these needs which,
while highly desirable to the Council, are unpredictable as to when they may pre-
sent themselves. It is suggested that Council may wish to reserve a significant
portion of the Encinitas capacity to meet such needs. I would recommend that the
remaining 270 EDUs be earmarked to meet this requirement.
It is staff's recommendation that the Encinitas Sanitary District lease capacity
of 75,000 GPD not be included in the allocation program as it is presently estab-
lished. It is staff's further recommendation that the Encinitas lease capacity
be committed to increasing available capacity for the City Capital Improvement
Program and for failed septic systems (35 EDUs) and, in addition, that the balance
of available capacity (270 EDUs) be committed to projects which Council may deter-
mine to be of special benefit to the community.
EDUs AVAILABLE FOR ALLOCATION
Assuming that Council concurs with staff's recommendations on the policy issues of
EDU flow rate, vacancy factor and Encinitas lease capacity, we will have total ca-
pacity rights equivalent to 14,361.4 EDUs with 2,040.96 EDUs available to meet legal
and policy commitments and to allocate in conformance with the allocation proced-
ures currently being formulated. The attached Worksheet No. 1 outlines the steps
leading to these numbers.
Should Council elect to leave the EDU flow rate unchanged and not approve the use
of a vacancy factor, Worksheet No. 4 outlines the calculations that would result in
1,244.56 EDUs available to meet legal, policy and allocation needs.
To help understand the use of the worksheets, it is appropriate to discuss some of
the constraints that exist regarding determination and distribution of available
EDUs. These are:
1. As of June 30th, 12,743 EDUs have been issued.
2. 66.67 EDUs have been committed to City Capital Improvement Projects and failing
septic systems. This item was inadvertently ommitted from consideration in the
October 12, 1978 report.
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3. Settlement of the Grove litigation provides for:
a. Assignment to Grove of 448 EDUs from the 640 EDUs indicated as available
in the October 12, 1978 report.
b. Assignment to Grove of 19.2% of any additional capacity found to exist at
the Encina plant. This 19.2% applies to an additional 81 EDUs determined
available as of October 12, 1978 (see note on Worksheet No. 2), to 46 EDUs
reserved for Plaza Camino Real expansion but never issued, to EDUs re-
claimed from recalculation of existing Plaza Camino Real expansion needs,
to additional capacity gained from recalculation and to additional capacity
gained from use of a vacancy factor.
c. 230 EDUs will be made available from the Vista Sanitation District.
Worksheet No. 2 attempts to pick up at the October 12, 1978 report and bring things
forward to the present. Accounting for errors made in earlier reports, for con-
ditions of the Grove settlement, and for Council actions regarding City needs, I
arrive at a total of 2,046.23 EDUs distributed as follows: allocation 1,318.58
EDUs; Grove 660.98 EDUs; Capital Improvement Projects 66.67 EDUs. This figure
exceeds the number arrived at on Worksheet No. 1 by 5.27 EDUs. I have been unable
to locate the exact source of this discrepancy but have tracked it to the methods
previously used to arrive at the 640 EDUs figure in the October 12, 1978 report.
Worksheet No. 3 ignores all previous actions except those that have obligated ca-
pacity or those that Grove might be able to claim as additional found capacity.
I arrive at a total of 2,040.56 EDUs distributed as follows: allocation 1,312.91
EDUs; Grove 666.98 EDUs; Capital Improvement Projects 66.67 EDUs. This figure
is only 0.4 EDU different from that arrived at on Worksheet No. 1. This discrep-
ancy is a result of rounding off the larger numbers and is within acceptable toler-
ance. I recommend that these figures be used.
SUMMARY
If Council concurs with staff recommendations, they will make the capacity avail-
able from ownership in the Encina plant and from the Vista Sanitation District
lease available to meet existing legal, policy and allocation program needs. This
action would result in assignment of available capacity as follows: __..
Available for second round allocation 1,312.91
Available to Grove, et al 660.98
Available to Capital Improvement Projects, et al 66.67
If Council concurs with staff recommendations regarding the Encinitas lease ca-
pacity, they will assign the 305 EDUs available as follows: 35 to supplement exist-
ing Capital Improvement Projects balance (66.67 + 35 = 101.67 EDUs total) and 270
as a special reserve to meet those needs that Council may determine to be of spe-
cial benefit to the community.
RECOMMENDATIONS
That Council approve a resolution changing the City's EDU flow rate from 253 GPD to
246 GPD; and further
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That Council accept, as a matter of policy, that the City's vacancy factor, in its
sewer service area, will never be less than 3% and that such additional EDUs as
may result be made available for allocation; and further
That the total EDUs available for the second phase allocation are 1,312.91 EDUs;
and further
That the Encinitas capacity is made available for use and that it shall be used to
create a category for projects of benefit to the community (270 EDUs) with the bal-
ance going to the existing City Capital Improvement Program and failing septic sys-
tem category raising it to a total of 101.67 EDUs.
A
Ronald A. Beckman, P.E.
Public Works Administrator
RABrVEB
Attachments
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/ / / / s
COLUMN -12 3 4 5•.———.,.-.. ,. -. .—,...— |——. .———,. — — ....„,- ,..._, ,.••- ,.,.•.!• „».,!... -. 1 ...^— . — —..•.-...., ..— — .. -„.! 1 II . .1 -.,—.-,.-
MO/YR
OCT 77
NOV 77
DEC 77
OAN 78
FED 78
PAR 78
APR 78
i'AY 78
JIM 78
OUL 78
AUG. 78
SEP 78
OCT 78
MOV 78
DEC 78
OAN 79
FEB 79
MAR 79
APR 79
KAY 79
OUN 79
*EXCEEDED
LEGAL
CAPACITY
FLOW
(MGD)
2.411
2.136
2.864
3.642*
3,497*
3,249
3.574*
2.659
2.707
2,282
2.590
2.880
2.842
2.628
2.910
3.228
3.042
2.817
2.784
2.766
3.097
,
CONNEC-
TIONS
12,097
12,110
12,138
12,145
12,162
12,188
12,195
12,211
12,429
12,521
12,551
12,568
12,585
12,585
12,721
12,721
12,722
12,730
12,733
12,741
12,743
3ROSS
EDU
199.3
176.4
235.0
299.9
287.5
266.6
v 293.1
217.8
217.8
182.3
206.4
229.2
225.8
208.8
228.8
253.8
239.1
221.3
218.6
217.1
243.0
•
CONTRIB .
CONNECT.
**to
84.0
84.0
84.5
84.5
84.5
85.5
85.5
85.5
86.5
87.0
88.5
89.0
89.5
90.0
90.5
91.0
91.5
92.0
92.5
93.0
93.0
*
ADJUSTED
CONNEC-
TIONS
'10,161
10,172
10,257
10,263
10,277
10,421
10,427
10,440
10,751
10,893
11,108
11,186
11,264
11,326
11,512
11,576
11,641
11,712
11,778
11,849
11,851
6
ADJUSTED EDU
FLOW RATE
237.3
210.0
279.2
354.9
340.3
311.8
342.8
254.7
251.8
209.5 .
233.2
257.5
252.3
232.0
252.8
278.8
261 .3
. 240.5
236.4
233.4
261.3
i
7
COMMENT
DRY
DRY
WET
WET
WET
WET
WET
DRY
DRY
DRY
DRY
DRY
DRY
DRY
DRY
i WET
WET
DRY
DRY
DRY
DRY
WORKSHEET NO. 1
TOTAL EDUs AVAILABLE
GPP
Capacity available at Encina Water Pollution Control Facility 3,430,000
Capacity leased from Vista Sanitation District 56,672
Capacity leased from Encinitas Sanitation District (not included in
allocation) —
TOTAL AVAILABLE CAPACITY 3,486,672
Assumed: EDU = 246 GPD
Vacancy Factor = 3%
Calculations: EDUs
1. 3,430,000 GPD * 246 GPD/EDU = 13,943.1
2. 13,943.1 EDUs x 1.03% = 14,361.4
3. Vista lease 56,672 GPD * 246 GPD/EDU = 230.0
4. #2 plus #3 = 14,591.4
5. Permits issued to date = 12,743.0
6. #4 minus #5 = 1,848.4
7. Permits recalled (Plaza Camino Real recalculation) = 192.56
8. #6 plus #7 = 2,040.96
TOTAL AVAILABLE FOR ALLOCATION, GROVE SETTLEMENT AND PARTIAL AMOUNT
FOR CAPITAL IMPROVEMENT PROJECTS (66.67 EDUs) IS 2,040.96 EDUs
WORKSHEET NO. 2
DISTRIBUTION OF AVAILABLE EDUs
Method No. 1
Assumed: EDU = 246 GPD
Vacancy Factor = 3%
Calculations: EDUs
1. EDUs per October 12, 1978 report + 640.0
2. Additional EDUs resulting from net overestimate (see note) + 81.0
3. Grove share of #1 - 448.0
4. Grove share of #2 (19.2%) - 15.5
5. Recalculation of Plaza Camino Real needs (EDUs reclaimed) + 192.56
6. Grove share of #5 (19.2%) - 36.97
7. Permits reserved for Plaza Camino Real expansion but not issued + 46.0
8. Grove share of #7 (19.2%) - 8.83
9. Additional capacity from reduction in flow rate (13,943 - 13,571) + 372.0
10. Grove share of #9 (19.2%) - 71.42
11. Additional capacity due to vacancy factor of 3% + 418.0
12. Grove share of #11 (19.2%) - 80.26
13. Leased capacity from Vista Sanitation District + 230.0
Net EDUs available for allocation (sum of all + and -) 1,318.58
Net EDUs to Grove (#3, #4, #6, #8, #10, #12) 660.98
Net EDUs to Capital Improvement Projects, et al 66.67
TOTAL EDUs 2,046.23
NOTE: The additional 81 EDUs result from two errors in the October 12, 1978 report.
The first error was an overestimation, by 156 EDUs, of issued permits for September,
1978 (12,724 estimated versus 12,568 actual). This overestimate is partially offset
by the error of neglecting to set some of the 640 EDUs aside for City projects. It
was assumed, in error, that the City allocation was in addition to the 640 EDUs.
WORKSHEET NO. 3
DISTRIBUTION OF AVAILABLE EDUs
Method No. 2
Assumed: EDU = 246 GPD
Vacancy Factor = 3%
Calculations EDUs
1. Total owned capacity (3,430,000 * 246) + 13,943.1
2. Permits issued - 12,743.0
3. Permits reserved for Capital Improvement Projects, et al - 66.67
4. Grove share - basic - 448.0
5. Permits reclaimed from Plaza Camino Real expansion + 192.56
6. Grove share of #5 (19.2%) - 36.97
7. Grove share of EDU flow rate reduction - 19.2% of (13,943 - 13,571) - 71.42
8. Additional capacity due to vacancy factor of 3% + 418.0
9. Grove share of #8 (19.2%) - 80.26
10. Grove share of 46 EDUs reserved for Plaza Camino Real but not issued* - 8.83
11. Grove share of 81 EDUs error in October, 1978 report* - 15.5
(see note on Worksheet No. 2)
12. Leased capacity from Vista Sanitation District . + 230.0
Net EDUs available for allocation (sum of all + and -) 1,312.91
Net EDUs to Grove (#4, #6, #7, #9, #10, #11) 660.98
Net EDUs to Capital Improvement Projects, et al 66.67
TOTAL EDUs 2,040.56
*City share included in #1.
WORKSHEET NO. 4
DISTRIBUTION OF AVAILABLE EDUs
Method No. 3
Assumed: EDU = 253 6PD
Vacancy Factor = 0%
Calculations: EDUs
1. [3,430,000 - 230,000 (wet weather flow)] * 235.8 + 13,571.0
2. Permits issued - 12,743.0
3. Permits reserved for Capital Improvement Projects, et al - 66.67
4. Grove share - basic - 448.0
5. Permits reclaimed from Plaza Camino Real expansion + 192.56
6. Grove share of #5 (19.2%) - 36.97
7. Grove share of 46 EDUs reserved for Plaza Camino Real but not issued* - 8.83
8. Grove share of 81 EDUs net overestimate in October, 1978 report* - 15.5
9. Leased capacity from Vista Sanitation District + 230.0
Net EDUs for allocation (sum of + and -) 668.59
Net EDUs to Grove (#4, #6, #7, #8) 509.30
Net EDUs for Capital Improvement Projects, et al 66.67
TOTAL EDUs 1,244.56
*City share included in #1.
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RESOLUTION NO._59JIZ _
A RESOLUTION OF THE CITY COUNCIL OF THE CITY OF CARLSBAD,
CALIFORNIA, DETERMINING THE NUMBER OF GALLONS OF SEWAGE
EQUAL TO ONE EQUIVALENT DWELLING UNIT AND ADOPTING IT AS
A REGULATION PURSUANT TO SECTION 13. 08. 081 (f) OF THE
CARLSBAD MUNICIPAL CODE _____ __
WHEREAS, Section 13.08.081 of the Carlsbad Municipal Code provides for
the determination of the amount of sewage generated from particular buildings
or uses based on a unit of measure of one equivalent dwelling unit which is
defined as equal to an approximation of the amount of sewage generated by an
average single-family residence; and
WHEREAS, Subsection 13. 08. 081 (f) of said section authorizes the City
Council to adopt regulations for applying it, including a determination of the
number of gallons of sewage which shall equal one equivalent dwelling unit; and
WHEREAS, the City Council desires to make that determination, upon recom-
mendation of the Public Works Administrator, in his memorandum of August 8,
|979;
NOW, THEREFORE, BE IT RESOLVED by the City Council of the City of Carlsbad
as fol lows:
|. The above recitations are true and correct.
2. The City Council determines that 246 gallons per day of sewage shall
be equal to one equivalent dwelling un'it.
3. This determination is adopted as a regulation pursuant to Subsection
13. 08. 081 (f) of the Carlsbad Municipal Code.
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PASSED, APPROVED AND ADOPTED by the City Council of the City of Carlsbad,
California, at a regular meeting held the 21 st day of August , 1979,
by the following vote, to wit:
AYES: Councilmen Packard, Skotnicki, Anear and
Counci1 woman Casler
NOES: None
ABSENT: Councilman Lewis
RONALD C. PACKARD, MAYOR
ATTEST:
yJ&£v /T
ALETHA L. RAUTENKRANZ, CITY CLERK
(SEAL)
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