HomeMy WebLinkAbout1979-11-20; City Council; 5761-3; Satellite Reclamation Master PlanCITY OF CARLSBAD
Initial:
AGENDA BILL NO. 5761 - Supplement #3 ^.——_——. Dept. Head jf<_
DATE: November 20, 1979 C. Atty
DEPARTMENT: Public Works C- M9^.
SUBJECT:
SATELLITE RECLAMATION MASTER PLAN
STATEMENT OF THE MATTER___, . ^
On June 5, 1979, Council awarded a contract for preparation of the Satellite Master -
Plan to Lowry & Associates. Council also awarded a contract for the preparation of
a Draft Environmental Impact Reporfon -the Master Plan. Both documents have been
prepared and presented to the City. Copies of each have been distributed to Council
for review.
While review of both documents is necessary to properly evaluate the proposals con-
tained in the Master Plan, it is the draft E.I.R. with its prescribed C.E.Q.A. process
that determines when both documents can be formally acted on by the Council. The
E.I.R. is now in the 45-day review period. Allowing two weeks for response to ques-
tions, then scheduling for Planning Commission public hearings, the documents should
be to the Council for public hearings and action in February or March.
The contract for preparation of the E.I.R. provides for further work in the form_of
responding to questions posed during the review period and appearing at the public
hearings. The contract requirements for preparation of the Master Plan has been
met. Council must accept the report for payment purposes in order to pay the con-
sultant the balance owed. Throughout the conduct of the study and the preparation
of the report, the consultant has met with staff to insure that their performance
of the terms of the contract was consistent with City policy.
RECOMMENDATION
It is recommended that City Council accept the report, Wastewater Reclamation Master
Plan Study, by Lowry & Associates for payment purposes.
Council Action:
11-20-79 The matter was continued. . •
11-28-79 - Continued to December 4, 1979
12-4-79 Council approved staff recommendation listed above.
CITY OF
"Waste Watef
Master
Study
SEPTEMBER 1B7B
owryssociates
,owrv f> /.. f..ssoclates c^^c,,
3505 Camino <Ll fcio,Soulk,Suit* 334,SanSbie9o,Ca/lfomia 92/08, ('14)283-7145
October 3, 1979
HONORABLE MAYOR AND CITY COUNCIL
City of Carlsbad
P. 0. Box 265
Carlsbad, CA 92008
Honorable Council Members:
Subject: Waste Water Reclamation Plan Study Report
We are most pleased to transmit to you with this letter
50 copies of our report, "City of Carlsbad, Waste Water
Reclamation Master Plan Study." The study was authorized
by Council Resolution No. 5800, adopted on June 6, 1979,
and was carried out in accordance with the terms of the
resolution. The study area encompasses the entire City
and its sphere of influence, with the exception of those
lands served by the Leucadia County Water District and
the San Marcos County Water District.
A recommended master plan for staged development of a re-
claimed water system incorporating several satellite
reclamation plants is presented in the report. At the
outset, the reclamation plants would primarily produce re-
claimed water for irrigation of agricultural lands. As
urbanization takes place, it is visualized that irrigation
of landscaping and open space in residential areas would
gradually supplement agricultural irrigation. Industrial
use of reclaimed water is encouraged, but cannot be quan-
tified without more detailed information of the nature of
Carlsbad's future industries.
In its initial phase, the recommended waste water reclama-
tion system would consist of several relatively small
satellite plants, each serving a limited nearby use area.
Over the years, capacity of the plants would be enlarged
and their distribution networks merged into a single system.
Eventually, the southerly and easterly sections of the City
would have dual water service, with reclaimed water furnish-
ed for all needs other than potable use.
• 7748 SKY PARK 8LVD . 'RVINE. CALIFORNIA 92714
714, 751-3820
HONORABLE MAYOR AND CITY COUNCIL
October 3, 1979
Page 2
All satellite plants other than that at Lake Calavera Hills
would be connected by treated effluent pipelines at the
Encinas ocean outfall for disposal of surplus reclaimed water.
These excess effluent disposal lines would also serve as
reclaimed water distribution lines. In a later stage, as
consolidation takes place, a pipeline connecting Lake Calavera
Hills to the ocean outfall would be installed.
Typical of a master plan effort, the accompanying report ap-
proached its task in the broad context. Alternatives are
examined in a general way and the recommended master plan is
presented in outline form. Thus, the adopted master plan
should constitute a flexible guideline for City Council and
staff as the reclamation program proceeds. However, the
recommended plan is intended to be sufficiently detailed to
permit implementation to begin without delay.
We wish to call your attention to a key recommendation in
the report dealing with water quality objectives. Present
groundwater quality objectives of the San Diego Regional
Water Quality Control Board require a substantial degree of
salt removal before reclaimed water can be used in much of
the study area. Desalting is costly and may vitiate the re-
clamation program, at least to a significant degree. It is
believed that the Regional Board will consider revision of
its groundwater quality objectives for the area upon receipt
of an adequately documented request from the City of Carlsbad.
We recommend that such a request be made.
The City of Carlsbad is to be complimented for its far-sighted
interest in waste water reclamation at this time. We trust
that the accompanying report will provide a potent tool to
guide your planning as you move toward enhancement of present
and future local water resources through reclamation.
Lowry & Associates appreciates very much having had the op-
portunity to prepare the recommended waste water reclamation
master plan. Please let us know if we can be of further
service.
Sincerely,
LOWRY & ASSOCIATE
&<
Dennis O'Leary
Senior Vice President
jay
Enclosures
TABLE OF CONTENTS
CHAPTER PAGE
I INTRODUCTION
Purpose 1-1
Authorization 1-3
Organization of Study 1-4
The Study Area 1-6
Background 1-6
Acknowledgements 1-9
II SUMMARY AND RECOMMENDATIONS
Introduction II-l
Regulatory and Water Quality
Considerations II-l
Production and Distribution of Reclaimed
Water II-2
Considerations Applicable to Waste Water
Reclamation Planning for Carlsbad 11-3
Comparison of Regional and Satellite Waste
Water Reclamation Programs 11-5
Analysis of Individual Satellite Waste
Water Reclamation II-5
Integration of Individual Satellite Waste
Water Reclamation Projects 11-6
Additional Planning Considerations 11-11
Recommendations for Implementation of a
Satellite Waste Water Plan by the City
of Carlsbad 11-12
III REGULATORY AND WATER QUALITY CONSIDERATIONS
Water Quality III-l
State Policy III-2
Regulatory Constraints III-3
Ground Water Quality Objectives III-5
Irrigation Criterion 111-8
IV PRODUCTION AND DISTRIBUTION OF RECLAIMED
WATER
Degree of Treatment IV-1
Reclaimed Water Distribution IV-1
Excess Effluent Piping IV-2
Storage Facilities IV-4
Effect on Encina IV-5
Reclamation System Capacity IV-7
Waste Water Quality Considerations IV-8 L
TABLE OF CONTENTS (Cont'd)
CHAPTER PAGE
V CONDITIONS APPLICABLE TO WASTE WATER
RECLAMATION PLANNING FOR CARLSBAD
Introduction V-l
Classification of Irrigation by Type V-l
Land Use V-2
Population Projections V-7
Waste Water Flows V-9
Availability of Sewage Flows for
Reclamation V-14
Reuse Markets V-15
Estimated Magnitude of Reclaimed Water
Market V-25
Flows from Upstream Agencies V-27
Reclamation Activities by Other Agencies... V-28
VI COMPARISON OF REGIONAL AND SATELLITE WASTE
WATER RECLAMATION PROGRAMS
General Concept VI-1
Cost Comparison of Separate and Regional
Concepts VI-2
Cost of Pumping VI-7
Ease of Implementation VI-8
Short-Term and Long-Term Disadvantages VI-9
Conclusion VI-10
VII ANALYSIS OF INDIVIDUAL SATELLITE WASTE
WATER RECLAMATION SYSTEMS
Introduction VII-1
Batiquitos Reclamation Facility VII-3
Palomar Airport Reclamation Facility VII-11
Encina Reclamation Facilities VII-18
Buena Vista Reclamation Facility VII-21
Lake Calavera Reclamation Facility VII-24
Agua Hedionda Reclamation Facility VI1-26
VIII INTEGRATION OF INDIVIDUAL SATELLITE WASTE
WATER RECLAMATION PROJECTS
Concept of Master Plan VIII-1
Phased Development of An Integrated System. VIII-1
Distribution Svstem VIII-5
ft
TABLE OF CONTENTS ( Cont'd)
CHAPTER PAGE
IX ADDITIONAL PLANNING CONSIDERATIONS
Regional Solids Handling IX-1
Contacts with Irrigators IX-3
Pricing Considerations for Reclaimed
Water IX-4
RECOMMENDATIONS FOR IMPLEMENTATION OF A
SATELLITE WASTE WATER PLAN BY THE CITY OF
CARLSBAD
General Conclusion X-l
Recommendations X-l
Purveying Agency X-2
Sale of Reclaimed Water X-3
Timing of Implementation X-6
Implementation Steps X-7
APPENDIX
RECLAMATION PLANT DESIGN PRINCIPALS
Reclamation Plant Design Features A-l
Waste Water Quality A-l
Reclaimed Water Quality A-l
Treatment Methods A-2
Sludge Handling Facilities A-3
Back-Up Odor Control Facilities A-4
Redundant Treatment Units A-4
Aesthetic Treatment A-5
Miscellaneous Features A-5
k
CHAPTER
III-l
III-2
III-3
III-4
III-5
III-6
III-7
III-8
III-9
111-10
V-l
V-2
V-3
V-4
V-5
V-6
V-7
VI-1
VII-1
VII-2
VII-3
VII-4
VII-5
VII-6
VII-7
VII-8
LIST OF TABLES
Anticipated Waste Water Characteristics
Total Dissolved Solids Levels
Title 22 Requirements for Irrigation
of Food Crops
Average Precipitation
Mean Temperatures
Class "A" Pan Evaporation (Southern
California Coastal Area)
University of California Criteria for
Irrigation Waters
Crop Salinity Tolerance
Average Crop Consumptive Use
Typical Water Balance
Estimated Land Available for Reuse
Waste Water Flows Available for
Reclamation
Estimated Urban Land Available for
Irrigation
Water Use in Residential Area
Cost Estimate Retrofit for Dual Water
System
Potential Industrial Uses
Anticipated Reclamation Programs of
Upstream Agencies
Table of Costs
Overview Report Projects Presents
Batiquitos Anticipated Reclaimed Water
Quality
Summary of Estimated Construction
Costs Batiquitos System
Palomar Anticipated Reclaimed Water
Quality
Existing and Projected Waste Water
Flows Palomar Airport Site
Summary of Costs Palomar Airport
System
Summary of Costs Encina System
Waste Water Flows Available Buena
Vista Reclamation Facility
PAGE
III-l
III-l
III-4
III-8-
III-8
III-9
111-10
111-10
111-13
111-15
V-5
V-13
V-18
V-19
V-21
V-24
V-28
VI-5
VII-2
VII-6
VII-10
VII-14
VII-14
VII-17
VII-20
VII-22
I
1v
LIST OF TABLES (Cont'd)
CHAPTER PAGE
IX-1 Estimated Effect of Solids Handling IX-2
at Encina
IX-2 Estimated Operation & Maintenance IX-5
Costs
X-l Reclamation Facilities Hypothetical X-7
Schedule
k
LIST OF FIGURES
CHAPTER PACE
1-1 Study Area 1-7
III-l Groundwater Quality Objectives III-6
III-2 Landscape Irrigation-Distribution of 111-12
Annual Requirements
III-3 Agricultural Irrigation-Distribution 111-14
of Annual Requirements
V-l City General Plan V-3
V-2 Existing Land Use V-4
V-3 Agricultural Land V-6
V-4 Population Projection for Study Area V-8
V-5 1978 Waste Water Flows in Study Area V-10
V-6 Projected 1985 Waste Water Flows in V-ll
Study Area
V-7 Projected Ultimate Waste Water Flows V-l2
in Study Area
V-8 Study Area Water Use V-l7
V-9 Proposed Future Parks V-22
V-10 Projected Reclaimed Water Use For V-26
Study Area
VI-1 Satellite Concept VI-3
VI-2 Regional Concept VI-4
VII-1 Batiquitos Plant Phase 1 (1985) VII-4
VII-2 Palomar Airport Phase 1 (1985) VII-12
VII-3 Lake Calavera Hills Phase 1 (1985) VII-25
VIII-1 Master Plan Initial Phase - 1985 VIII-3
VIII-2 Master Plan Intermediate Phase - 1995 VIII-6
VIII-3 Master Plan Ultimate Phase - 2005 VIII-7
X-l SDG&D Projected Power Cost X-4
X-2 Estimated Unit Cost of Water X-5
VI
CHAPTER I
INTRODUCTION
PURPOSE
In investigating various ways to alleviate its current sewer mora-
torium, the City of Carlsbad is continuing to give serious consideration
to waste water reclamation as a means of providing additional treatment
capacity. At the same time, the City is fully aware that waste water rec-
lamation can furnish a significant source of supplemental water supply,
with adequate pre-planning for reclaimed water use. Irrigated agriculture,
still an important activity within and adjacent to Carlsbad, is perceived
as an immediate and near-term market in the face of potential future short-
ages of potable water supply. Additional opportunities to substitute re-
claimed water for potable water are under consideration, particularly open
space and landscape irrigation, a demand that is expected to increase
commensurately with City growth.
The Lake Calavera Hills waste water reclamation project implements
the satellite concept in the northeast area of Carlsbad. Before giving
further consideration to additional satellite treatment plants in other
areas served by the municipal sewer system, the City Council desires to
develop a master plan for waste water reclamation within its jurisdication.
The master plan would indicate location and capacity of potential waste
water reclamation plants, opportunities for use of reclaimed water and
associated volumes, approximate costs, and approximate scheduling. It
would provide the foundation for making more specific decisions on the
viability of future reclamation proposals, as to both concept and detail.
The contemplated master plan would take into account the program al-
ready developed for Lake Calavera Hills as an element of citywide reclama-
tion activities, including possible future consolidation with reclaimed
water distribution and excess effluent disposal networks. At the same
time, it would provide a means of coordinating with reclamation activities
presently being effected within the City by the Leucadia County Water
District and the San Marcos County Water District in their respective juris-
dictions. Thus, the immediate focus of the master plan study effort would
be upon those portions of the City outside of the Lake Calavera Hills,
Leucadia County Water District and San Marcos County Water District service LLareas. •-
The study described in this report was undertaken with the objective
of recommending a waste water reclamation plan in keeping with the City's
desires and needs. Following systematic review of alternatives, recommenda-
tions are made for adoption of a plan that will provide sound and logical
guidance toward establishing a network of reclamation satellites within the
City. Once adopted, the reclamation master plan can provide a reference
document for the City Council; moreover, it should be invaluable to City
staff in planning for reclamation projects, and in review of projects pro-
posed by other agencies and private parties.
An accompanying environmental impact report (EIR) analyzes effects
of the reclamation program on the environment and on the social
structure of the City.
The primary advantage that will accrue from the construction of rec-
lamation and reuse facilities will be the creation of a supplemental water
supply within the study area. A secondary advantage is the provision of
additional waste water treatment facilities in a timely manner, at minimum
cost to.the City.
The importance of supplemental water supply stems from water short-
ages expected to develop in the San Diego area in the mid-1980's. These
shortages could result from diversion of Colorado River water to the Central
Arizona Project, and possible increased use of Colorado River water by the
City of Los Angeles. Failure to implement the Peripheral Canal in the
Sacremento Delta area could also contribute to shortages.
Opportunities for waste water reclamation and reuse in the City of
Carlsbad have been the subject of considerable study and discussion over
the past few years. In March of 1978, Lowry & Associates presented a
report entitled Overview of Waste Water Possibilities to the City Council
and this report was reviewed and accepted in principal by Council action.
Following the submittal of a proposal for the construction of a waste
water reclamation plant to serve the proposed Lake Calavera Hills develop-
ment, the City retained James M. Mongtomery, Inc., to prepare a project
report and EIR for a satellite plant to serve the northeast section of the j,
City, draining to Agua Hedionda Lagoon. I
1-2
AUTHORIZATION
This work has been undertaken by Lowry & Associates in accordance with
the terms of an agreement with the City of Carlsbad. That agreement was
approved by Resolution No. 5800, adopted by the City Council on June 5, 1979.
SCOPE
The study presented herein was performed for the purpose of formulating
a waste water reclamation master plan to be recommended for adoption by the
City of Carlsbad. The area covered by the study includes the entire City
of Carlsbad and its sphere of influence area, with the exception of both
those areas encompassed by the study Environmental Impact And Facilities
Plan For A Satellite Sewage Treatment Facility (James M. Montgomery, Con-
sulting Engineers, Inc., December 1978) and lands served by special sewerage
districts. As explained, a plan now exists for the former area and special
sewerage districts are in the process of developing their own waste water
reclamation plans.
The study areas are broken-down into subareas based upon configuration
of the City of Carlsbad interceptor and trunk sewer systems. Subareas are
designated as follows:
Buena Vista
Agua Hedionda
Coastal
Coast
Upper Cayon De Las Encina
Batiquitos
The study includes a review and screening of projects and alternative
sites for reclamation plants. Scope of the individual projects is estab-
lished through an analysis of the reuse market potential in each area.
Waste water flows available for reclamation are analyzed and incorporated
into the project concept.
1-3
Waste water quality is determined in order to establish the degree of
treatment necessary for various uses, both from a practical standpoint and
to conform to regulatory constraints. Design concepts are contained in
Appendix A. Overall cost parameters are established in order to prepare
budget estimates for the various projects. Finally, the development of an
integrated reuse system is analyzed and presented. Specific recommendations
for implementation of the program are presented.
The recommended plan is not intended to become a waste water treatment
and disposal program. Rather, it should provide for creation of a supple-
mental source of water for the community. For this reason, the designation
of reuse areas is presented on a general basis without identifying specific
irrigation areas responsible for disposing of the effluent from a particu-
lar treatment plant.
ORGANIZATION OF STUDY
The information presented in this report is based on a number of
engineering, environmental, and planning reports prepared for the City of
Carlsbad, other public agencies in the area, and for private developers
over the past several years. Principal among these was the report entitled,
An Overview Of Waste Water Reclamation Opportunities, prepared by Lowry &
Associates for the City of Carlsbad in March 1978.
This master plan study is organized to first present basic population
and land use data, followed by an explanation of reclamation concepts and
descriptions of initial construction projects. Finally, the combining of
individual reclamation plants into an integrated system capable of providing
reclaimed water on a demand basis throughout the service area is described.
1-4
1. Information Pertinent to Waste Water Reclamation
The information presented consists of data pertinent
to Carlsbad that can be utilized to develop specific rec-
lamation projects. Population projections are used to
estimate the future waste water flow which can be reclaimed
and reused. This information is followed by information
on present and future land use patterns, from which the
potential market for reclaimed water can be estimated.
The combination of these two factors, reclaimed water sup-
ply and reuse markets, form the basis of the recommended
reclamation master plan.
2. Satellite and Regional Concepts
The next section of the study is devoted to an analysis
of the advantages and disadvantages of a satellite reclama-
tion system as compared to a system utilizing regional rec-
lamation systems.
3. Description of Satellite Program
The portion of the study immediately following the com-
parison of concepts is utilized to present a detailed des-
cription of the satellite plant concept. The principles
involved, together with the facilities which must be con-
structed, are explained at this point.
4. Individual Reclamation Facilities
The following major portion of the study is devoted to
the description of individual satellite facilities that are
considered in the first phases of the reclamation master
plan.
5. Integrated Reuse System
Integration of the individual reclamation facilities
into an overall reuse system covering the entire study area
is the subject of the last major portion of the study.
Methods by which the individual plants are joined together
and operated as a single system are described.
6. Implementation
Final section is devoted to a brief summary of the
conclusions and a list of specific implementation steps.
The recommended waste water reclamation master plan itself
is shown and described in Plate A in the rear pocket. /-
ftI
1-5
This report does not present details of design of individual reclama-
tion plants. It is anticipated that the scope of specific projects will be
developed by City staff when specific proposals are submitted to the City
by developers or when funding for City sponsored projects becomes available.
At that time, specific planning for individual projects will be performed
in accordance with the concept presented in the reclamation master plan.
THE STUDY AREA
The area covered in this study includes the City of Carlsbad and its
sphere of influence, with the exception of lands served by the Leucadia
County Water District (LCWD), and lands served by the San Marcos County
Water District (SMCWD).
Initially, the service area of the proposed Lake Calavera Hills Rec-
lamation Plant had been excluded from the study area. However, after
consideration it was determined that, since the Lake Calavera Hills Plant
will be an integral part of the recommended reclamation master plan, this
area should be included. Although it was not considered-in the discussion
of individual reclamation facilities, the Lake Calavera Hills area is in-
cluded as a part of the final recommended reclamation master plan.
The boundaries of the study area are shown on Figure 1-1. Within
that boundary, a detailed examination is made of the water reclamation
opportunities, including potential reuse markets, quality requirements,
waste water availability, reclamation plant locations.
BACKGROUND
Over past years there has been a considerable interest in reclamation
and reuse of waste water in Southern California. Such programs are usually
directed toward conservation of water and energy, along with provision of
a supplemental water supply. As a result, the City is now seeking to de-
velop a comprehensive waste water reclamation and reuse program. In part,
«
I
1-6
LAKE CALAVERA
STUDY AREA
COUNTY
• •- STUDY BOUNDARY
anticipation of possible water shortages in Southern California by the mid-
1980' s is prompting many local agencies to consider similar programs.
If shortages do develop, there may be necessity for Devaluating entire
classes of water use. A shortage of potable water is certain to bring
pressure to limit marginal uses, either in the form of differential rates,
or outright rationing of potable supplies. Domestic water use will certain-
ly have first priority. However, experience in the recent drought con-
ditions and during periods of temporary shortage indicate that water agencies
are quick to impose restrictions on lawn watering, car washing, and other
non-vital domestic uses.
It is reasonable to assume that as water shortages occur the use of
potable supplies for landscape irrigation will come under criticism. At
that time, the availability of reclaimed water will become vitally import-
ant if landscape irrigation and similar lesser priority uses are to be
continued.
Agricultural use of imported water in San Diego County is based on
the legal concept of "excess water." This means that the primary use of
the imported water supply is intended to be for domestic purposes, and
that agricultural use can take place only after domestic needs are satisfied.
Such a definition would seem to automatically eliminate agricultural uses
as the water supply becomes more critical. It is possible that farm inter-
ests might be able to to legislate reduced supplies for agricultural pur-
poses as the general supply becomes critical. However, it is obvious that
the existence of an alternate supply of reclaimed water would be essential
if cost-effective irrigation is to be continued under such circumstances.
This view of the future demonstrates the importance of developing a
waste water reclamation and reuse program as soon as possible. The
existence of even the rudiments of such a system will make the transition
to a water short situation much easier. With this in mind, the recommended
reclamation master plan places emphasis on the value of an early start.
Waste water reclamation facilities established at this time should form the
nucleus of a regionwide system. Provision of waste water reclamation
iti
1-8
facilities throughout the Carlsbad region can be expected to accelerate,
should water shortages materialize in the mid-1980's. Early experience
with reclamation and reuse will have inestimatable value as the situation
develops.
Waste water reclamation and reuse has long been recognized as a sound
conservation practice and a wise use of a limited natural resource. However,
reclaimed water has not been utilized extensively because of the economics
of the water supply systems of Southern California. Even in our semi-arid
climate, raw water is supplied at nominal costs. This is due, to a great
extent, to the fact that most of the capital investment for major water
supply systems has long since been depreciated. The purchase price of
water is further reduced by tax funding utilized by the major suppliers.
At the opposite extreme from these broadly-funded water projects are
the few reclamation projects presently in existence. These tend to be
individual locally financed systems with the entire capital and operational
costs of producing reclaimed water assigned to the project. Historically,
this has meant that the cost of reclaimed water to the consumer is greater
than the purchase price of an equal volume of potable water.
The cost of potable water has increased significantly in recent years
and is expected to increase further in the 1980's. Already, the price
structure has reached the point where reclaimed water can, under certain
circumstances, be provided at a price competitive with that of the potable
water supply.
ACKNOWLEDGEMENTS
Lowry & Associates wishes to acknowledge the assistance rendered in
the preparation of this report by all members of the City Engineering,
Planning and Administrative staff. Valuable assistance was also received
from staffs of other public agencies in the area, from the Comprehensive
Planning Organization and from the San Diego County Department of Sanita-
tion and Flood Control.
1-9
Particular contributions were made by the following persons:
Paul D. Bussey City Manager
Ronald A. Beckman Public Works
Administrator
Lester G. Evans City Engineer
Thomas C. Hagaman Associate Planner
Charles D. Grimm Assistant Planner.
k
1-10
CHAPTER II
SUMMARY
AND
RECOMMENDATIONS
This chapter contains a brief summary of the information presented in
this report. The major items discussed and the conclusions reached are
presented on a chapter-by-chapter basis.
INTRODUCTION (CHAPTER I)
The introductory chapter explains the purpose, authorization, scope,
and organization of the study. The study area covered in the report is
defined as the sewerage service area of the City of Carlsbad. This is, in
essence, the City of Carlsbad and its sphere of influence, with the excep-
tion of lands served by the Leucadia County Water District and the San
Marcos County Water District. The Lake Calavera Hills study area covered
in a previous report is also included within the study area. In view of
anticipated shortages of potable-water in the area during mid-1980's, a
program of reclamation and reuse would conserve water and energy and provide
a supplemental supply of water to the area for agricultural uses, landscape
irrigation and industrial use.
REGULATORY AND WATER QUALITY CONSIDERATIONS (CHAPTER III)
A critical consideration in any waste water and reuse program is the
matter of water quality. Anticipated waste water characteristics are such
that no unusual problems in treatment are anticipated. The most important
constituent of interest is the total dissolved solids (TDS) in the waste
water and reclaimed water. This characteristic is important both with
reference to regulatory constraints and the salt tolerance of irrigated
crops and landscaping. Toxic materials must be completely"eliminated frcm
the sewerage system by means of a source of a control program.
Reclamation and reuse projects are subject to regulation by the Stats
Regional Water Quality Control Board, the State Department of Health
Services, and the County Health Department. The regulations and require-
ments established by these agencies can be met with present technology
within reasonable economic parameters. Planning must also conform to air
quality standards, zoning regulations, and other similar requirements.
Specific requirements and compliance methodology will be determined at the
time of final design of the individual projects.
Regulations established by the State Department of Health Services for
reclamation plants require assurance of proper operation of facilities with
any single unit out of service for maintenance or repair.
Regulatory constraints imposed by the Regional Water Quality Control
Board profoundly affect the reclamation program. Enforcement of ground-
water quality objectives established by the Regional Board for total dis-
solved solids would require demineralization by reverse osmosis throughout
much of the study area. Operating costs for demineralization would require
charges for reclaimed water well in excess of present rates for agricultural
irrigation water. It is recommended that the City petition the Regional
Board for a revision of groundwater objectives in some portions of the
study area. Revisions that would eliminate the need for demineralization
would reduce the cost of reclaimed water below that for potable water.
Regional Board staff has indicated that they would be receptive to a request
for revision.
The Regional Water Quality Control Board has established groundwater
objectives for IDS within each hydrologic sub-basin within the San Diego
area. Direct irrigation with reclaimed water will require adherence to the
so-called "one-third" rule. Demineralization by reverse osmosis will be
necessary to meet this requirement.
PRODUCTION AND DISTRIBUTION OF RECLAIMED WATER (CHAPTER IV)
Reclaimed water meeting both regulatory and practical requirements
can be produced from the anticipated waste water supply by well-established
treatment technology. The salt content of the reclaimed water will
necessitate advanced waste treatment facilities in the form of demineraliza-
tion. Compliance with health requirements for the use of reclaimed water
in areas in close proximity to human activity may require advanced waste
11-2
treatment in the form of coagulation, clarification, and filtration.
Irrigation of food crops will require the same advanced waste treatment
steps.
The reclaimed water will be distributed to areas of reuse by a separ-
ate water system, which must be clearly distinguishable from the potable
water supply of the City. It was determined that this distribution piping
can be combined with excess effluent pipes delivering reclaimed water to the
ocean outfall at Encina.
Storage facilities are a vital part of any reclamation and reuse
system. The amount of storage provided will determine the percentage of
reclaimed water which can beneficially be reused. Reclamation of the
total output of a particular plant will require large seasonal storage
facilities. Access to the ocean outfall for disposal of excess reclaimed
water will reduce storage needs but will also reduce the total volume
available for reclamation.
The only major effect on Encina of the development of a reclamation
and reuse program will be to delay the necessity for constructing addition-
al treatment facilities at Encina beyond the time in which they would
otherwise be required. Use of the Encina ocean outfall for excess effluent
disposal will require modification of the federal NPDES permit and waste
discharge requirements when flow volumes through the outfall approach 18 MGD.
CONSIDERATIONS APPLICABLE TO WASTE WATER RECLAMATION PLANNING
FOR CARLSBAD (CHAPTER V)
Two types of irrigation with reclaimed water were defined in the
study by James M. Montgomery Engineering Company. Type I irrigation would
apply to uses which substitute reclaimed water for potable water in
existing or proposed irrigation activity. Type II irrigation was defined
as "Irrigation for the principal purpose of disposing of reclaimed water.1'
All of the irrigation practices discussed in this report are Type I usages.
k
11-3
Existing land use plans for the study area are utilized to define
potential reuse markets for the initial stages of the reclamation and reuse
program. The City General Plan is followed to project ultimate reuse markets
for the program.
Population projections are of primary importance in the planning of
reclamation projects. The Comprehensive Planning Organization's (CPO)
Series IV-B projection is generally accepted for phasing purposes by local
government agencies.
An analysis of existing land use and ultimate land use as determined
by the City General Plan indicates that in the early phases of the reclama-
tion program, agricultural reuse will be of primary importance. As land is
urbanized and taken out of agricultural use, there will be a slight increase
in the reuse market if all of the landscaped and open space areas mandated
by present City regulations are irrigated with reclaimed water. This means
that the reclamation and reuse program is not necessarily dependent upon
maintenance of agricultural uses in the City.
Industrial use was not determined to be a major potential market for
reclaimed water at this time; industrial demand will depend upon future
planning by individual industrial firms, virtually impossible to forecast
at the present time.
Future sewage flows from upstream member agencies of the Encina
Joint Powers group will be substantial. Three of these agencies discharge
their waste water into interceptor sewers which pass through the study area.
Reclamation programs within the upstream agencies will limit the quantity
of their waste water available for reclamation in Carlsbad. However, studies
indicate that there will be as much as 5.6 MGD of flow available from this
source.
II-4
COMPARISON OF REGIONAL AND SATELLITE WASTE WATER RECLAMATION
PROGRAMS (CHAPTER VI)
There are two general master plan concepts which could be followed in
formulating a reclamation program for the City of Carlsbad. One is the
satellite concept, visualized as a number of relatively small facilities
located in upstream areas close to the reuse markets. The other concept
would involve a single major regional reclamation facility located at the
Encina plant.
It is virtually impossible to develop a firm cost comparison between
the two systems because of the large number of variables and the decisions
which must be made regarding allocation of costs and origin of funds. How-
ever, a broad "order of magnitude" approach to the subject indicates that
there is less than a 10%differential between the two concepts. The satellite
concept is expected to be slightly more costly than the regional concept.
Cost comparison includes the capitalized cost of pumping effluent back from
the central plant to the areas of reuse.
The satellite program can be implemented with greater flexibility than
the regional approach, since a satellite system would consist of a number
of individual projects which can be planned and financed separately.
Further, the satellite approach keeps a greater number of options open as
the program develops.
In view of the greater flexibility and potential for quicker implemen-
tation of the satellite program, that approach has been selected as the
basis for the recommended reclamation master plan for Carlsbad.
ANALYSIS OF INDIVIDUAL SATELLITE WASTE WATER RECLAMATION
SYSTEMS (CHAPTER VII)
Chapter VII is devoted to a discussion of details of specific reclama-
tion plants considered for the recommended reclamation master plan. Facil-
ities discussed are those which would be constructed in the first phase of
fti
II-5
the program, when each reclamation plant is essentially a separate, inde-
pendently operating system.
Four satellite reclamation plants form the basis for the program. The
location, reuse market, waste water flow, excess effluent connection and
storage facilities for each of these are discussed. These facilities are
summarized on the following data sheets. Total reclamation capacity is
expected to be 6.6 MGD by 1985. This will increase to a minimum of 7.5 MGD
by 1995.
INTEGRATION OF INDIVIDUAL SATELLITE WASTE WATER RECLAMATION
PROJECTS (CHAPTER VIII)
The recommended reclamation master plan anticipates that the individual
reclamation projects discussed in the preceeding chapter will, over the
years, be integrated into a single reclamation and reuse system. Three
time periods are considered: the initial phase, ending in 1985; the
intermediate phase, running through 1995; and the ultimate phase, arbi-
trarily selected as the year 2005.
During the initial phase of the program, each of the reclamation
facilities will operate on an independent basis. During this time, it will
be necessary to have firm contracts with users of the reclaimed water to
assure an adequate market.
During the intermediate phase of the program the various independent
systems will be interconnected by the excess effluent lines. By that time,
major storage facilities will be constructed. During the ultimate phase of
the program, the system will operate on a completely "demand" basis, with
reuse customers being able to withdraw water from the excess effluent dis-
tribution piping system whenever they wish. Additional storage will be pro-
vided during this ultimate phase in order to maximize use of the reclaimed
water.
11-6
SITE SELECTION
LIMITS
DATA SHEET
BATIQUITOS RECLAMATION FACILITY
RECLAMATION
Capacity
(MGD)
ANNUAL REUSE
(Acre-Feet/Year)
STORAGE VOLUME
EXCESS EFFLUENT
CONNECTION
(Diameter in Inches)
ADVANCED WASTE
TREATMENT
* Demineral ization by
1985 1995
0.2 0.4
200 400
20 40
12 12
None *
Reverse Osmosis
2005
1.0
1000
100
12
*
11-7
*e ^55^^-v^-'
SITE SELECTION
LIMITS
DATA SHEET
PALQMAR AIRPORT RECLAMATION FACILITY
RECLAMATION
Capacity
(MGD)
ANNUAL REUSE
(Acre-Feet/Year)
STORAGE VOLUME
EXCESS EFFLUENT
CONNECTION
(Diameter in Inches)
ADVANCED WASTE
TREATMENT
*Deminera1ization by
1985
2.5
1500
80
18
*
Reverse Osmosis
1995
5.0
3000
200
2@18
*
2005
5.0
5000
500
2@18
*
J
11-8
1000 0 IOOO
SCALE IN FEET
DATA SHEET
ENCINA RECLAMATION FACILITY
RECLAMATION
Capacity
(MGD)
ANNUAL REUSE
(Acre-Feet/Year)
STORAGE VOLUME
EXCESS EFFLUENT
CONNECTION
(Diameter in Inches)
ADVANCED WASTE
TREATMENT
1985
00
0
0
None
None
*Coagulation, Clarification &
**Deminera1ization by Reverse
1995
•0.9
500
0
None
*
Filtration
Osmosis
2005
1.9
1500
0
None
**
II-9
> IOOO 0 IOOO
I
SCAUE IN FEET
DATA SHEET
LAKE CALAVERA HILLS RECLAMATION FACILITY
RECLAMATION
Capacity
(MGD)
ANNUAL REUSE
(Acre-Feet/Year)
STORAGE VOLUME*
EXCESS EFFLUENT
CONNECTION
(Diameter in Inches)
ADVANCED WASTE
TREATMENT
Underground
1985
0.5
500
300
None
None
1995
1.2
1000
600
None
None
2005
1.2
1300
800
12
None
11-10
ADDITIONAL PLANNING CONSIDERATIONS (CHAPTER IX)
There are a number of additional planning considerations which will
influence the recommended reclamation master plan.
The feasibility of using the Encina plant as a central location for
handling all sludge solids from satellite plants throughout the area served
by that plant is now being seriously considered. Reports by consulting
engineers for Encina indicate that regional solids handling could be carried
out at Encina if additional sludge digestion and dewatering facilities were
constructed at that location. These findings were verified in the course
of this study. If Encina were to become the regional sludge handling center,
it would still be desirable to provide sludge handling capabilities at each
of the reclamation plants.
As has been previously discussed, the ultimate reclamation and reuse
system will provide reclaimed water on a demand basis for all customers.
However, during the initial stages of the program, individual contracts will
be required to assure a ready market for reclaimed water. Landscape irri-
gation within new developments can be expected to constitute a major portion
of the reuse market.
Determination of the pricing policies for reclaimed water is beyond the
scope of this study. However, some background information is presented,
indicating that the capital cost for waste water treatment will probably be
borne by private developers, grant funds or governmental sources outside of
the general fund of the City of Carlsbad. For this reason, it is not con-
sidered essential to recover these costs through the sale of reclaimed
water. Advanced waste treatment facilities necessary to produce a reclaimed
water suitable for irrigation use are treated in the same manner. The cost
of secondary treatment of waste water should be borne by the sewer service
charge levied against all users in the City of Carlsbad.
11-11
The result of eliminating these costs from the funds that must be
recovered by the sale of reclaimed water leaves only operation and main-
tenance (O&M) costs for advanced waste treatment and distribution of re-
claimed water.
RECOMMENDATIONS FOR IMPLEMENTATION OF A SATELLITE WASTE WATER
PLAN BY THE CITY OF CARLSBAD (CHAPTER X)
The general conclusion reached in this study is that a waste water
reclamation and reuse program is desirable and feasible and should be
adopted and implemented by the City of Carlsbad. This program can be
supported in its early stages with minimum capital funds from the City by
requiring contributions from private developers and by accepting grant
funds. Once the system is established, revenue from reclaimed water sales
would be used to finance the expansion of the system in a manner similar
to that followed in expanding potable water systems. Development of a
fiscal program was beyond the scope of this study.
It is recommended that, as a matter of policy reclaimed water be
offered for sale at no less than its true cost of production and distribu-
tion, after deducting the cost of sewage treatment.
A series of implementation steps is recommended. These consist of the
acceptance of this report and the adoption of a program of waste water
reclamation and reuse by the City of Carlsbad. Specific requirements for
implementation are as follows:
1. Accept report and approve plan recommended in Chapter 10.
2. Establish reclamation as a formal City plan.
3. Certify E.L.R.
4. Distribute report.
5. Adopt ordinances to implement plan.
6. Establish policy of receiving proposals to construct recla-
mation projects. J4.
11-12
7. Instruct staff to develop funding guidelines.
8. Petition Regional Board to modify groundwater objectives
in specified areas.
9. Encourage use of reclaimed water for agricultural and
landscape irrigation.
11-13
CHAPTER III
REGULATORY AND
WATER QUALITY CONSIDERATIONS
WATER QUALITY
A critical consideration in planning for waste water reclamation is
the matter of water quality. Chemical constituents of waste water used for
reclamation purposes, quality of the reclamation plant effluent, regulatory
requirements and actual crop needs must all be considered. In the past,
the study area has been supplied with potable water from the Colorado
River. Presently, however, a blended water consisting of 50% Colorado
River water and 50% Northern California water is being furnished. Antici-
pated waste water characteristics for both the Colorado River supply and
the blended supply are shown in Table III-l. The data are based on normal
increments of biological and chemical constituents expected with one cycle
of domestic use. Waste water characteristics indicated in Table III-l do
not present any unusual problems in treatment.
The most important constituent of interest is the total dissolved
solids (TDS) in the waste water and reused water. Typical values for
TDS in the anticipated water supply and in the waste water are given in
Table II1-2. In order to meet the requirements for TDS content of
irrigated water in certain controlled areas, it may be necessary to pro-
vide demineralization facilities at the reclamation plant. This is a
relatively expensive operation and could seriously affect the sales of
reclaimed water. The effects of this question of TDS control will be dis-
cussed in following sections of this report.
TABLE III-l
ANTICIPATED WASTE WATER
CHARACTERISTICS
ITEM
CONCENTRATION
img/1)
oiocnernical Oxygen Demand 250
Suspended Solids 250
Total Dissolved Solids:
«ith Colorado River Supply 1COO
Viitn Slendea Supply SOO
"otal Phosphorus 10
"otal Nitrogen 30
TABLE III-2
TOTAL DISSOLVED SOLIDS LEVEL
(Average Values)
CONCENTRATION
Colorado River Water
Blended Water Supply
Increment Due to One Cycle of
Comestic Use
Ground <later Objectives
'/-.here ADD! icaDie)
Safe Agricultural Limitations
'00 - 900
500 - 5CO
Toxic materials must be completely eliminated from the system. Since
treatment for toxic removal would be prohibitively expensive, the only feasi-
ble method of controlling toxic substances is by a source of control program,
which prevents introduction of toxics into the waste water flow. Federal
law (40CFR403) now requires agencies operating publicly owned sewage
collection, treatment and disposal systems to establish and enforce effec-
tive industrial waste pre-treatment programs meeting federal criteria.
Thus, intensive source control will be necessary at most locations, whether
or not waste water reclamation is instituted.
STATE POLICY
Where waters of the United States are not involved, the law con—
trolling water quality in the State of California is the Porter Cologne
Act. This act is the basic authority under which the State Water Resources
Control Board (SWRCB) and the nine Regional Water Quality Control Boards
(RWQCB) operate. The importance of reclamation and reuse was recognized
officially by the State Water Resources Control Board in adopting its
Policy and Action Plan for Water Reclamation in California in January. 1977.
This policy was adopted to implement the legislative direction con-
tained in Water Code Section 13512. The policy states:
"The factors compelling the initiation of an
action plan involving many agencies and enti-
ties are (a) impending water shortages in cer-
tain areas of California (b) the high level of
treatment now given to waste waters, and (c)
the constraints and unknowns involved with the
use of reclaimed water to augment 'fresh water1
supplies".
As a further recognition of the need to encourage waste water re-
use, Governor Brown formed the Office of Water Recycling (OWR) with the
avowed purpose of increasing the use of reclaimed waste water by 400,000
acre feet per the year in the State. OWR administers programs at the
state level intended to implement federal actions and to promote local /•
programs involving waste water reclamation and reuse. V
III-2
REGULATORY CONSTRAINTS
Reclamation and reuse projects are subject to regulation by the State
Regional Water Quality Control Board, the State Department of Health
Services and the County Health Department. All three of these agencies
exercise coordinated control over the reuse of reclaimed waste water. How-
ever, the principal control is exercised by the Regional Board through
issuance of waste discharge requirements for all waste water treatment plant
or reclamation facilities.
For purposes of this study, it is important to understand that regula-
tions and requirements established by the various agencies can be met with
present technology, usually within reasonable economic parameters.
In addition to_ the primary control exercised by the Regional Water
Quality Control Board and the health agencies, air quality standards, zoning
regulations, and other similar requirements may also impinge upon the pro-
ject.
As the various reclamation projects proceed to final design, it will
be necessary to consult with the regulatory agencies regarding the specific
application of certain regulations as they affect design. The recommenda-
tions for design given in Appendix A will form an adequate basis of design.
Many of these constraints have been established in a conservative manner
to protect the public health and water quality. As reuse experience is
gained, some regulations may be relaxed, thus simplifying the operation
and reducing the costs over the years.
Public health regulations contained in Title 22 of the California
Administrative Code require that provision be made for satisfactory opera-
tion of reclamation facilities at times when any individual treatment unit
may be out of operation for maintenance or repair. In order to comply with
these "reliability" requirements, it is necessary to either provide re-
dundant units, or to utilize design criteria sufficiently conservative to
permit marginal operation with one unit out of service. Design of each
reclamation plant must be analyzed to demonstrate satisfactory operation
with critical units out of service.
III-3
The degree of treatment and bacterial limits required by the
Department of Health for the irrigation of food crops are shown in
Table III-3.
TABLE II1-3
TITLE 22 REQUIREMENTS
FOR IRRIGATION OF FOOD CROPS
A. Reclaimed water must be treated as follows:
1. Oxidized - Subjected to biological
secondary treatment process.
2. Coagulated - Dosed with a coagulating
chemical and mixed to form relatively
heavy suspended particles.
3. Settled - Allowed to stand quiescent
so that particles will settle out by
gravity.
4. Filtered - Passed through a sand, car-
bon, or artificial filter bed so that
smaller particles are removed by strain-
ing or adsorption.
3. Reclaimed water must be disinfected with
chlorine to the following levels of coliform
count (by most probable numoer method).
1. Median level less than 2.2 per 100 ml.
2. Maximum (not more than once every 30
days) 23 per 100 ml.
C. An alternative treatment method using fil-
tration and extended chlorine contact may
be substituted for the system described above.
The maximum salt content of the reclaimed water is established by
the Regional Board based on ground water objectives for the basin in
which the reclaimed water will be used. The objectives are established
to protect existing beneficial uses of the ground water. The objectives
for each sub-basin are listed in the Comprehensive Water Quality Control
Plan for the San Diego Basin, (Basin Plan).
III-4
In addition to conformance with regulatory requirements, salt content
of the reclaimed water must be controlled to prevent crop damage when the
water is used for irrigation. Under some circumstances, sensitivity of
certain types of vegitation to salts will impose more severe limitations
on reclaimed water salinity than the requirements of regulatory agencies.
Typical salinity tolerance for local crops will be discussed later in
this chapter.
GROUND WATER QUALITY OBJECTIVES COPY
The Regional Water Quality Control Board has established ground water
quality "objectives" for each hydrologic sub-basin within the San Diego area.
Objectives were established in order to protect existing beneric-cl ir=s.
The numerical objectives for each sub-basin are shown in the Comprehensive
Water Quality Control Plan for the San Diego Basin, (Basin Plan), adopted
by the Regional Water Quality Control Board with the approval of the State
Water Resources Control Board and EPA.
The most critical water quality objective applicable to irrigation
with reclaimed water is the permissible level of total dissolved solids
(TDS). As pointed out above, permissible levels may vary from place to
place, depending upon the hydrologic sub-basin and location within the sub-
basin. Figure III-l shows the TDS objectives applicable to various points
within the study area, ranging from "no objective" to values of 1,000 mg/1
and 1,200 mg/1. The southerly portion of the study area, between Inter-
state 5 and El Camino Real, could be considered for a relaxation of TDS
objectives, since the beneficial uses within this area are minor. While
some of the area has no ground water objectives, Hydrologic subunit 4.40 has
ground water objectives of 1200 mg/1.
Irrigation within that area having a ground water quality objective
of 1,200 mg/1 TDS will require demineralization in order to comply with
the so-called "one-third" rule of the Regional Board. This rule is based
on the assumption that approximately two-thirds of the irrigation water is
utilized for evaporation and evapotranspiration. The remaining one-third r
ft
III-5
i- EBE IMP
NO OBJECTIVE
1200 MG/l
1000 MG/L
PRESENTLY 10OO-12OO MG/L
PROPOSED NO OBJECTIVE
0
HYDROGRAPHIC SUBUNIT
NUMBER
• •• STUDY BOUNDARY
BROUIMOWATEP? DUALITY
OBJECTIVES
is assumed to percolate into the ground water, carrying the concentrated
salts from the entire original application. To limit the impact of salt
upon usable ground water the Regional Board requires that the original
irrigation water can have a IDS content no greater than one-third of the
ground water objective for IDS. Unless this rule is modified, demineraliza-
tion facilities must be provided to reduce reclaimed water IDS to a con-
centration of 400 mg/1 where the ground water quality objective is 1200
mg/1 IDS.
A discussion with the staff of the Regional Board has revealed that
the Board would be receptive to a proposal to eliminate the ground water
objectives in much of the area where the agricultural market now exists.
Based on available water quality data, the present ground water objectives
in the agricultural areas appear to be unnecessarily stringent. There-
fore, the City of Carlsbad has an opportunity to petition the Regional
Board to eliminate the ground water objectives within the study area.
The petition to the Regional Board would have to address itself to an
analysis of the quantity and quality of existing beneficial use in the
affected basin. The area suggested for revision is shown on Figure III-l.
Neither the Regional Board or Lowry & Associates staff has found any
existing wells in the area proposed for revision of ground water objectives.
If a full examination of the area indicates that there are, in fact, no
beneficial uses in existence, there will be little objection to the relaxa-
tion of the criteria. A request for a revision to the Basin Plan accom-
panied by engineering and hydrogeologic exhibits would have to be submitted
by the City to the Regional Board. While the preparation and submittal
of such data is beyond the scope of this study, it is felt that such a
oetition would receive favorable action.
Pending such a change in ground water objectives, the treatment
facilities considered in this study and discussed in this report are
adequate to meet existing regulations. If, in the future, the ground
water objectives for portions of the study are revised, the demineraliza-
tion equipment now prepared will not be required. Other treatment facili-
ties would remain the same as presented herein.
III-7
IRRIGATION CRITERION
The general findings of a number of detailed irrigation studies are
summarized in the following sections. Data presented include irrigation
requirements, storage needs, climatological information and other pertinent
data. The data presented represents conservative criteria, as employed in
a number of individual design projects in the North County area. These
criteria guide planning and evaluation of the various alternatives to be
considered.
Climatological Data
The irrigation needs of any landscaping or agricultural crop are de-
pendent, to a great extent, on the climate in the growing
precipitation and its distribution throughout the year are
most important of the climatological factors. Temperature
figures are also important. Data for Carlsbad,extracted
San Diego County", U.C. Extension, 1970, are presented in
through III-6.
•* m•^Vi
area. Annual
perhaps the
and evaporation
from "Climates of
Tables II 1-4
DE9I
COPY
TABLE III-4
AVERAGE PRECIPITATION*
i
MONTH Inches
I January 1.96
February 2.52
March 1.60
April .96May .18
June .06
July .02
August . 10
September .13
October . 47
November .90
December 1.80
j ANNUAL 10.70
•From Oceanside Station as reported
in "Climates of San Diego County",
UC Ext. Service, 1970.
TABLE III-5
MEAN TEMPERATURES*
MONTH
January
February
March
April
May
June
July
August
September
October
November
December
YEAR
MAXIMUM
61.2
61.3
62.6
63.9
66.0
68.1
71.3
72.9
72.2
59.6
67.3
64.0
66.7
•From Oceanside Station
'Climates of San Diego
Service, 1970. All in
MEAN MINIMUM
51.9 42.6
52.7 44.0
54.2 45.6
56.9 49.9
59.8 53.6
62.6 57.1
66.5 61.2
67.2 61.5
65.5 58.3
61.7 53.3
57.4 47.4
54.1 44.1
59.2 51.6
as reported in
County", UC Ext.
Degrees Fahrenheit.
k
III-8
TABLE II1-6
CLASS "A" PAN EVAPORATION
(SOUTHERN CALIFORNIA COASTAL AREA)
MONTH
January
February
March
April
May
June
July
August
September
October
November
December
ANNUAL
*From "climates of
UC Ext. Service,
INCHES
2.5
3.3
4.1
4.9
5.8
6.6
7.0
7.0
5.8
4.6
3.6
3.1
58.3
San Diego County,"
1970.
Water Quality
Irrigation water quality has been divided into three classes by agri-
cultural scientists. Characteristics of each class are given in Table III-7.
As can be seen, the important criteria are TDS, chloride content, and per-
cent sodium. For the purposes of this study, it is assumed that Class II
irrigation water will be satisfactory. This class of water is good for
general purpose agricultural irrigation and landscape irrigation. Care
must be taken in selecting salt tolerant plants, particularly in landscaping
projects. However, as pointed out earlier, a reclaimed water quality of
about 800 mg/1 TDS is anticipated, a level acceptable for most irrigation
purposes.
k
III-9
TABLE II1-7
UNIVERSITY OF CALIFORNIA
CRITERIA FOR IRRIGATION WATERS*
FACTORS
CLASS 1-
EXCELLENT TO
GOOD
CLASS 2-
GOOD TO
INJURIOUS
CLASS 3-
INJURIOUS TO
UNSATISFACTORY
Electrical Conduct-
ance, ECxlQfi 325-C
Total Dissolved
Solids**
Boron, ppra
Chloride/ ppm
Percent Sodium
Less than 1,000 1,000 - 3,000 More than 3,000
Less than 700 700 - 2,000 More than 2,000
Less than 0.5 0.5-2.0 More than 2.0
Less than 175 175 - 350 More than 350
Less than 60 60 - 75 More than 75
'From Bulletin No. 104-7, State Department of Water Resources
••Computed from EC
Notes: Class 1 - Excellent to Good. Regarded as safe and suitable
for most plants under any conditions of soil or
climate.
Class 2 - Good to Injurious. Regarded as possibly harmful
for certain crops under certain conditions of
soil or climate, particularly in the higher range
of this class.
Class 3 - Injurious to Unsatisfactory. Regarded as probably
harmful to most crops and unsatisfactory for all
but the most tolerant.
Typical salinity tolerance for local crops are presented in Table III-8,
TABLE III-8
CROP SALINITY TOLERANCE
CROP TCS
(mg/1}
Avocados 800
Oranges 1000
Tomatoes 1500
Lemons 1100
Grapefruit 1100
Tangerines 1100
Miscellaneous - Vegetables 1100
Strawberries 600
Miscellaneous - Fruits & Huts 1000
Pasture & Landscape Grasses 1500
k
111-10
To assure marketability, reclaimed water should have a IDS content
compatible with its planned uses. A IDS concentration of 800 mg/1 or
less would be considered comparable to the unblended Colorado River supply.
With the current water supply consisting of a 50-50 blend of Northern
California water and Colorado River water, reclaimed water with a IDS con-
centration approximating 800 mg/1 can be delivered without demineralization.
This can be accomplished only if self regenerating water softeners are
prohibited within the sewer service area and sources of industrial wastes
are adequately controlled. Should the quality of the domestic water supply
degrade, demineralization facilities would again become necessary.
Reclaimed water which must be demineralized in order to meet Regional
Board standards will be of a considerably higher quality than otherwise
available. It is conceivable that reclaimed water of such high quality may
be marketed at premium rates in small quantities, perhaps distributed by
trailer/truck to florists and other speciality growers.
Urban Consumptive Use
Landscape water needs are somewhat higher than those of agriculture.
Irrigation of landscaping normally extends throughout the year, whereas
agricultural irrigation is usually seasonal. In addition, there is a ten-
dency to overirrigate landscaping, since the activity is aesthetic rather
than economic.
Typical total annual consumptive use for landscaping is shown in i
Table III-9. Figure III-2 presents a monthly distribution of total land- !j
scape needs. This data is based on experienced obtained at the Irvine I
Ranch Water District, where landscaping irrigation has been closely monitored i
for several years.
k
ni-n
20%
O
Z
* 15%
UJ
O
UJo
Z
UJo
UJ
Q.
0%
JAN. FEE MAR. APR. MAY JUNE JULY AUG. SEPT. OCT. NOV. DEC.
MONTH
LANDSCAPE IRHIGAT1OIM
DISTRIBUTION OF ANNUAL REQUIREMENTS
FIGURE 111-2 k
111-12
TABLE II1-9
AVERAGE CROP CONSUMPTIVE USE
(INCHES)
MONTH
November
December
January
February
March
April
May
June
July
August
September
October
TOTAL
AVOCADOS*
2.
2.
2.
2.
2.
3.
3.
3.
4.
4 .
3.
2.
36.
4
2
1
2
7
0
5
3
2
0
4
9
4
DECIDUOUS
FRUIT*
2
2
3
4
4
4
4
3
3
32
.3
0
0
0
.0
.4
.0
.3
.7
.5
.8
.3
.3
CITRUS*
2.
1.
1.
1.
2.
2.
3.
3.
3.
3.
3.
2.
32.
^9
9
9
4
7
2
4
3
6
1
6
6
PASTURE*
2.
2.
2.
2.
3.
4.
4 .
S.
5.
5.
4 .
4.
48.
8
6
6
6
7
1
9
2a
5
7
1
6
LAWN 4* *
LANDSCAPE
2.
2.
1.
1.
1.
2.
2.
4.
7.
7.
5.
3.
42.
5
1
3
3
7
1
9
2
5
5
1
8
0
'Applies to Western San Diego County area.
"Applies to Irvine Ranch Water District.
Agricultural Consumptive Use
There has been a considerable body of data accumulated on the consump-
tive use of various agricultural crops. Information from the Soil Con-
servation Service for coastal San Diego County areas is also shown in
Table III-9. These data indicate that crop needs vary from 2.5 inches per
month to 4.0 inches per month, distributed unevenly throughout the year.
Figure III-3 shows a typical annual distribution of the total agricultural
needs, which can be utilized for preliminary planning of irrigation projects.
Agricultural irrigation needs are more likely to vary from year to
year. In wet years there will be a considerable reduction in agricultural
irrigation demand, whereas irrigation requirements will tend to increase
in drier years. In addition, as indicated, wintertime irrigation use will
be essentially zero, since growers take advantage of natural rainfall during
this period.
in-13
25%
20%
2 15%
UJ
Q
_J
<
O
u. lo°/°-
O
UJ
z
UJ
O 507(T ° /0
UJ
Q.
0%
JAN. FEE MAR. APR. MAY JUNE JULY AUG. SEPT. OCT. NOV. DEC.
MONTH
AGRICULTURAL IRRIGATION-DISTRIBUTION
OF ANNUAL REQUIRMEiMTS
FIGURE 111-3 k
111-14
H
E
P
1
•1
.
|
|
I
1
E
C
c
1
1
1
1
1
Water Balance
The concept of water balance takes into account consumptive use require-
ments of the planned irrigation activity, precipitation characteristics and
ability to store water in determining how much acreage can be irrigated with
a given annual volume of water. It is highly desirable to base reclaimed
water irrigation planning on the water balance concept. A typical water
balance calculation is presented in Table 111-10, which makes use of assumed
data. Such a calculation must be made for any reclaimed water irrigation
project which incorporates reclamation of the total annual output of water.
Similarly, it is advantageous to employ the water balance concept for
projects other than total waste water reclamation to relate peak summer
month demands with storage requirements for most effective use of a given
volume of water.
TABLE I II -10
TYPICAL WATER BALANCED
| RAINFALL 110% RUNOFF AVAIL. PLANT IRR. TOTAL LOSS TOTAL
MO. (2) RAINFALL 920» (3) RAINFALL USE(4) REQ'D IRR. «10%(5) SPRAYED
OCT .43 .47 .09 .38 4.05 3.67 3.67 .37 4.04
NOV 1.70 1.87 .37 1.30 2.34 1.34 1.34 .13 1.47
DEC 2.61 2.87 .57 2.30 2.60 .30 .30 .03 .33
1 JAN 2.89 3.18 .64 2.54 2.55 .01 .01 .00 .01
FEB 2.51 2.76 .55 2.21 2.61 .40 .40 .04 .44
MAR , 2.71 2.98 .60 2.33 3.69 1.31 1.31 .13 1.44
APR 1.77 1.9S .39 1.56 4.12 2.56 2.56 .26 2.82
MAY .46 .51 .10 .41 4.87 4.46 4.46 .44 4.90
JUN .05 .06 .01 .05 5.23 5.18 5.18 .52 5.70
JUL .08 .09 .02 .07 5.78 5.71 5.71 .57 6.28
! AUG .19 .21 .04 .17 5.51 5.34 5.34 .53 5.87
1 SEP .19 .21 .04 .17 4.73 4.56 4.56 .46 5.02
| 15.59 17.16 3.42 13.74 48.58 34.84 34.34 3.48 38.32
(1) All data in inches per month (4) Grassland per Soil Conservation
(2) Average rainfall (assumed) Service
(3! Assume 20% runoff (5) Spray loss assumed 10\
ki
111-15
CHAPTER IV
PRODUCTION AND DISTRIBUTION
OF RECLAIMED WATER
k
DEGREE OF TREATMENT
It is necessary to provide a treatment which will meet all the require-
ments the Regional Water Quality Control Board and the health departments
and provide a safe, reliable and odor-free operation.
Because reclamation plants may be constructed in close proximity to
developed areas, a high degree of operating reliability is desired. The
plants must operate odor-free. Experience has shown that the activated
sludge process is capable of achieving a high level of operational reli-
ability while being essentially odor-free. Sludge should either by trans-
ported to a regional handling facility or aerobically digested. In
addition, odor control measures, such as building enclosures, air filters,
scrubbers, and exhaust systems, should also be designed into the system
as additional safeguards.
Treatment facilities for reducing organic and suspended material in
the waste water and for providing adequate disinfection can readily be
designed. All of the reclamation plans included in the recommended recla-
mation master plan will utilize conservative engineering practices for the
design of adequate facilities. Design criteria to be utilized for reclama-
tion plants are given in Appendix A.
RECLAIMED WATER DISTRIBUTION
A vital element of any reclamation and reuse program is a provision
of a reclaimed water distribution system. Such a system is established to
receive effluent from the waste water reclamation plant and pump, store,
and distribute reclaimed water for beneficial use.
Piping in a separate reclaimed water distribution system can often be
made up in large part by disconnecting existing agricultural distribution
lines from potable supply lines. In residential areas, however, it will be
necessary to provide two parallel systems, one conveying potable water to
homes, and the other furnishing reclaimed water to landscape irrigation
facilities. Irrigation of residential landscaping with reclaimed water is
carried on in close proximity to human activity and is therefore subject to
stricter controls by the Regional Water Quality Control Board and State
Department of Health Services. A "dual water supply system" is subject to
a producer/primary user permit from these agencies.
EXCESS EFFLUENT PIPING
Waste discharge requirements issued by the Regional Water Quality
Control Board will prohibit the discharge of reclaimed water to streams
or water courses at any time. In the winter when irrigation needs are
minimal and when storage facilities are full, it will be necessary to dis-
pose of excess effluent in some acceptable manner. The most practical way
of doing this, other than by providing large and expensive storage facil-
ities, is by a pipe connection to the ocean. Each plant producing reclaimed
water will have to be provided with a connection to the Encina ocean out-
fall so that the treated effluent not required for irrigation purposes and
for which storage capacity is unavailable can be discharged in compliance
with the waste discharge requirements.
In this study, the term excess effluent connection or excess efflu-
ent line will be used in lieu of "fail-safe". It is believed that the
term is more descriptive and less confusing. Without excess effluent
connections, reclamation projects would be limited by the volume of winter
storage available. Plants would have to be sized so that the available
reservoirs could store all of the winter flow not required for irriga-
tion purposes during those months. The alternative is to overirrigate
during the winter months, using more water than actually required. This,
however, introduces a waste water disposal aspect to the program. Since
this study concerned with beneficial reuse of reclaimed water, disposal
systems employing overirrigation are not considered a legitimate appli-
cation of the concept of reuse.
The concept followed in this study is to provide a separate line
from the reclamation plant directly to the Encina ocean outfall so that ff
IV-2
excess secondary effluent can be discharged directly to the ocean. The
route of these excess effluent lines will, in all probability, pass through
areas of potential reuse. The lines can therefore serve a double purpose.
They can act as outlets to the ocean and also distribute reclaimed water
to the areas of reuse. Every attempt will be made to locate these lines
so as to maximize their suitability for this double use. It appears at
this time that piping can be laid out so as to provide for this double
use by connecting the various satellite plants to a series of pipelines
that will be joined at or near the Encina plant. The pipes/will function
in a manner similar to a conventional potable water distribution system.
Since it is assumed that reuse will be on a demand basis in the
future, the distribution pipelines will have to be made large enough to
accommodate simultaneous demands throughout the entire reuse service area.
The actual size of the lines will be determined at the time of final design.
Factors influencing the design will include peak to average flow ratios,
exact location and elevations of the points of reuse, size and location of
storage facilities, and other similar technical parameters. Distribution
pressures will be on the order of 10 psi to 20 psi. These relatively low
pressures are established in anticipation of requiring each reuser to pro-
vide pumps to bring the pressure up to whatever level is required for his
particular use.
The other agencies in the Encina system, which will be undertaking
reclamation programs of their own, can participate in the use of the dis-
tribution and excess effluent pipeline system if they so desire. Par-
ticipation in construction and operation of this system will eliminate
the necessity for these upstream agencies to build fail-safe connections
all the way to the ocean outfall. If these agencies were to plan to use
Carlsbad's excess effluent pipelines, it would be necessary to increase
the size of these lines. A decision to use the excess effluent system
will therefore have to be made by the upstream agencies, prior to the time
that Carlsbad undertakes actual construction of the facilities. The pipe
sizes utilized in this study do not include any flow from upstream areas.
IV-3
STORAGE FACILITIES
As has been previously explained, the amount of storage volume con-
structed in the system will directly affect the total amount of reclaimed
water available for reuse. The location of the storage facilities is of
importance when planning the distribution pipeline sizes. The location
of major storage reservoirs will be determined by site conditions. There
are relatively few suitable locations in the study area. Consequently,
the size of thdtjreclamation plants will be greater than would be the case
if unlimited storage volumes were available.
As the reclamation and reuse system grows from a series of inde-
pendent projects to an integrated distribution system it may be found
feasible to construct smaller equalizing reservoirs at strategic points on
the distribution system. These balancing reservoirs would be particularly
useful when the system starts to operate on a "demand" basis. Short periods
of high demand could be satisfied by withdrawals from the equalizing reser-
voirs in the same way that a potable water system operates. With equalizing
reservoirs a greater quantity of water could be delivered through a given
pipe system or, conversely, a given quantity of water could be delivered
through a system of smaller diameter pipe.
The exact location, size, and elevation of the equalizing reservoirs
will depend upon the locations, quantity, and frequency of the reuse demand.
Consequently, the planning of these smaller storage facilities must be de-
layed until the actual market develops.
Previous studies carried out by Lowry & Associates in the Leucadia,
San Marcos, and Carlsbad area indicate that sites for major storage reser-
voirs are relatively scarce and expensive to develop. A survey of the
entire study area using topographic maps supplemented by field reconnais-
sance was carried out. This survey confirmed previous experience by
indicating a scarcity of locations suitable for large scale storage.
Varying irrigation requirements from month to month would make it
necessary to provide 90-day to six-month storage volune if all of the L
IV-4
reclaimed water is to be beneficially reused. This fact can be demon-
strated by a water balance analysis of any reclamation project. The alter-
nate approach is to provide some lesser volume of storage and to waste a
portion of the reclaimed water to the ocean. The smaller volume of storage
will permit flexibility in day to day or week to week irrigation operation.
With a given treatment capacity, the percentage of reclaimed water benefi-
cially reused will vary directly with the volume of storage. Using this
principle, the storage volume should be as great as possible. A 30-day
volume was used as a standard in this study.
Only one major surface storage reservoir capable of holding any-
where near 30-day production of proposed reclamation plants was found.
This site will be utilized in the layout of the recommended reclamation
master plan.
Groundwater basins can be utilized as storage facilities in the same
manner as aboveground reservoirs. Underground storage has the additional
advantage of providing additional treatment as the reclaimed water perco-
lates through the soil. If adequate ground water basins were available,
this method could be utilized for all of the necessary storage capability.
Unfortunately, in the Carlsbad area there are only limited groundwater
aquifers available for this purpose. Location of aquifers was mapped by
the State Department of Water Resources in Ground Water Occurrence and
Quality: San Diego Region, Bulletin 106-2. The only aquifer of suitable
size is located in the Agua Hedionda Basin. This basin is presently being
studied for possible future use by the Lake Calavera Hills Reclamation
Facility, and will be incorporated into the recommended master plan. No
accurate estimate has been made of the possible volume of this basin.
EFFECT ON ENCINA
The Encina facility was originally conceived and planned to provide
a central point of waste water treatment for all member agencies of
the Encina group. It was intended to be expanded in increments to handle
increasing waste water flows from the member agencies. At the present time, zf
IV-5
treatment capacity is 13.75 MGD, with primary treatment only. Phase III
expansion of Encina will provide both primary and secondary treatment for
a flow of 18.0 MGD. Site planning studies indicate that the ultimate
treatment capacity of the facility will be physically limited by the size
of the site to a flow of 45.0 MGD. Additional treatment capacity beyond
that level would have to be provided at alternative sites.
The creation of a series of satellite reclamation plants would con-
stitute a departure from the previous waste water disposal policy of
Carlsbad. Hitherto all waste water was transported to a single point for
treatment and disposal by discharge to the ocean. With the construction
of satellite plants there will be more flexibility permitted in waste water
planning for Carlsbad. It will no longer be necessary to rely on capacity
at Encina for all of the waste water treatment capability required by
Carlsbad. Consequently, there will be substantial effects on the future
of operations at the Encina Water Pollution Control Facility. An analysis
of the effects of the construction of a system of satellite plants is
necessary in order to be certain that there will be no duplication of effort
or waste of funds.
The ultimate effect of providing additional treatment capacity at
satellite facilities would be to supplement the capacity at Encina and to
provide additional treatment capacity beyond the 45.0 MGD capability. Viewed
in this light, the construction of satellite plants in no way duplicates
the need for capacity at the central location. The existence of satellite
plants may allow more time until treatment capacity above the 18.0 MGD
level is required at Encina.
Preliminary indications are that the amount of treatment capacity pro-
vided by satellite plant construction may satisfy all the needs of the City
of Carlsbad for several years into the future. This might mean that
Carlsbad will not need to participate in the Phave IV expansion of Encina,
depending upon the timing and size of that expansion.
IV-6
Use of the Encina ocean outfall for disposal of excess effluent
from satellite plants in Carlsbad and other Encina Joint Powers agencies
will increase flows through the ocean outfall. Hydraulic studies carried
out for Encina indicate that an increase in outfall capacity can be
physically accomplished by construction of a low-head pump station. The
need for additional outfall capacity would occur whether or not satellite
plants were constructed, as a result of normal growth among the
participating communities.
It will be necessary to obtain a new federal permit for any increased
discharge through the ocean outfall above 18 million gallons per day.
However, the Encina Joint Powers will eventually have to take this step
whether or not a waste water reclamation program is instituted.
In summary, reclaimed water may be produced by a regional reclamation
plant at Encina or by means of a system of satellite plants at various
locations in the study area. It appears that the creation of a system
of satellite plants will affect planning at Encina only with regard to
timing of treatment facility expansion. Since the treatment capacity of
the satellite plants will supplement that of Encina, additional facili-
ties will be required there at somewhat later dates than would be neces-
sary if the satellite system were not implemented. There will be essential-
1y no effect on the timing of increased ocean outfall capacity.
RECLAMATION SYSTEM CAPACITY
The capacity of a reclamation and reuse system depends upon the re-
lationship between reclamation plant capacity, volume of storage available,
pattern of reuse, and ability to discharge excess effluent to the ocean
when necessary. As these variables change, the volume of waste water
actually reclaimed will vary considerably.
At one extreme, in a system with no storage, reclamation plant capacity
would constitute the maximum reuse rate available at any given time. Dur-
,,g periods when reuse rates are less than maximum, all excess effluent
IV-7
would be discharged to the ocean. At the other extreme, a system with
unlimited storage would permit all reclaimed water to be stored until
needed for use. In this case, there would be 100% use and no discharge to
the ocean. Where a particular system falls between these two extremes
will depend upon the amount of storage that can be economically provided.
Since the Encina ocean outfall is conveniently accessible, this study
will consider provision of reclaimed water treatment capacity equal to
anticipated needs for the maximum month of the year. Storage volume would
then be limited to that required for balancing peak demands. If
necessary, enlarged storage facilities could be added to the system to
meet unanticipated future growth of reclaimed water demand. Creation of
seasonal storage capacity at the expense of future water users would
increase availability of reclaimed water without having to expand treatment
plant capacity.
WASTE WATER QUALITY CONSIDERATIONS
Experience with the Encina system and elsewhere in San Diego County
has revealed that waste water reaching coastal treatment plants usually
has a significantly higher salt content than found in normal domestic sewage
flows. One reason for this phenomenon may be infiltration of brackish water
along the sewer lines in coastal areas. A higher quality of waste water
can be expected at inland locations, where satellite plants would be
constructed. Therefore, the satellite concept could involve less ex-
oenditure for demineralization facilities than might be necessary if a
regional reclamation plant were located on the coast.
The Carlsbad City Council has established a policy with precludes use
of industrial waste water in reclamation projects. This restriction is
based on concern about the possibility that industrial waste might be
harmful to treatment and sludge digestion processes. Normally, a fraction
of the regional sewerage system flow consists of waste from industrial
plants which utilize the community sewers for disposal. Waste water
k1
IV-8
presently arriving at the Encina Joint Powers plant conveys an increment of
industrial waste to the facility. Satellite reclamation plants located
peripherally on a system may be located so that little or no industrial
waste is commingled with the sewage flows being processed.
(t
IV-9
CHAPTER V
CONDITIONS APPLICABLE TO
WASTE WATER RECLAMATION PLANNING
FOR CARLSBAD
k
INTRODUCTION
This portion of the report presents information useful in planning
the specific projects which will constitute the recommended reclamation
master plan. The information has, for the most part, been assembled
from previously issued planning reports, engineering studies and other
similar sources. Major references include the following:
Overview of Waste Hater Reclamation Opportunities, March 1978,
(Lowry & Associates);
Areawide Water Quality Management Plan, March 1978, (Daniel,
Mann, Johnson & Mendenhall and Lowry & Associates);
Comprehensive Water Quality Control Plan Report, July 1975,
(State Water Resources Control Board and Regional Water
Quality Control Board, San Diego Region);
Encina Regional Sewerage Survey, November 1971, (Brown and
Caldwell);
Sewerage System Improvement Program, November 1976, (Brownge Syste
1 dwe 11);and Caldwell); and
City of Carlsbad-Environmental Impact Report and Facilities
Plan for a Satellite Sewage Treatment Facility, December 1978,
(James M. Montgomery, Consulting Engineers, Inc.).
CLASSIFICATION OF IRRIGATION BY TYPE
The previous engineering study carried out for the City of Carlsbad
by James M. Montgomery, Consulting Engineers, Inc., entitled
City of Carlsbad, Environmental Impact Report and Facilities Plan for A
Satellite Sewage Treatment Facility, referred to two types of irrigation
with reclaimed water. Type I would include those uses which would re-
place potable water. During the discussion of the Montgomery report,
it was established that Type I irrigation applies equally to existing
and future uses. Therefore, irrigation of landscaped areas not yet in
existence will constitute a Type I use.
Type II irrigation use of reclaimed water was defined as "irrigation
for the principal purpose of disposing of reclaimed water" Such irrigation
would by definition not occur if reclaimed water were not available. In
essence, Type II irrigation use is a waste water disposal practice, rather
than a reclamation and reuse.
All irrigation with reclaimed water discussed in this report would
fall into the category of Type I. Irrigation practices as part of the
recommended reclamation master plan will be either to replace present
agricultural water uses, or to irrigate landscaped areas to be developed in
the future which would otherwise have to be irrigated with potable water.
LAND USE
An important factor in the development of the recommended reclamation
master plan is land use pattern, both existing and proposed. The land
use and population elements of the City General Plan were utilized to
perform this study. Discussions with the Planning Department staff
indicated that the General Plan will not be radically revised in future
years so that the several land use patterns shown at this time will re-
main fixed throughout the time period covered by the reclamation master
plan. Figure V-l presents specific categories of land use excerpted from
the General Plan. The various land use classifications have been combined
into more general groupings, namely, dense residential, single family
residential, commercial, agricultural and industrial. These are the uses
of particular interest to reclamation planning. In a similar manner,
existing land use is plotted on Figure V-2. The two maps represent
present and ultimate land use patterns within Carlsbad. Present land uses
within the study area include approximately 3800 acres of agricultural
land. Not all of this land is irrigated every year depending on market
conditions. At the present time, there is no urban property being
irrigated with reclaimed water. However, it is assumed that 75% of area
development will be so irrigated within the coming years.
k
V-2
I
OJ
L EG E IMP
COMMERCIAL
RESIDENTIAL
OPEN SPACE
GOVERNMENT/INDUSTRIAL
5 || OTHER
m •••• STUDY BOUNDARY
CITY GENERAL PLAN
L E Q EM D
COMMERCIAL
RESIDENTIAL
AGRICULTURAL
OTHER
it•• STUDY BOUNDARY
EXISTING LAMP UBE
In 1975, the Comprehensive Planning Organization (CPO) inventoried
agricultural land uses in the Carlsbad area. The inventory identified
two categories, intensive crop agriculture and field crops. In addition,
the City Planning Department has compiled a map of the active agriculture
lands within the coastal zone. Figure V-3 shows the location of lands
either currently being used for agricultural activities or which have
been so used within the last five years. The agricultural land is
located almost exclusively in the area south of Agua Hedionda Lagoon and
Creek and north of Batiquitos Lagoon and San Marcos Creek. The estimated
total area classified by CPO as agricultural land is approximately 3800
acres. This area is provided w.ith domestic and agricultural water by
the Carlsbad Municipal Water District (CMWD).
The CPO inventory identifies 4900 acres of agricultural land within
the CMWD boundaries. For the same year, CMWD reported a total water
sales to agriculture of 3,968 acre feet. Thus, agriculture consumed an
average of 0.8 acre feet of water per gross acre of agricultural land.
Multiplying this water demand figure by the amount of agricultural land
within the study area, the present annual agricultural demand within the
study area is approximately 3,000 acre feet per year. Estimated
agricultural land available for reuse is shown in Table V-l.
TABLE V-l
ESTIMATED LAND AVAILABLE FOR REUSE
YEAR
1985
1995
2005
2015
1
AGRICULTURAL
(ACRES)
3,800
2,800
1,900
1,200
V-5
Ien
0c
LEOENP
AGRICULTURAL
STUDY BOUNDARY
AGRICULTURAL LAND
POPULATION PROJECTIONS
Estimates of future population size and distribution are of primary
importance in planning reclamation projects. The source of reclaimed water
is waste water produced by the resident population. For this reason, the
population projections made by various planning agencies are of primary
importance to this report.
The Comprehensive Planning Organization's (CPO) Series IV-B population
projection is generally accepted for phasing purposes by all government agen-
cies within San Diego County. Series IV-B population projections for the
study area show the 1985 population within the study area to be approxi-
mately 42,800; and the 1995 population to be approximately 63,000 people.
According to the Carlsbad General Plan, the ultimate population of the
study area is 154,000 people. It should be remembered that all population
projections are subject to revision, depending upon demographic trends;
for example, CPO periodically updates its preditions and is now involved
in developing its Series V, an update of Series IV-B.
Population projections in previous engineering studies by Brown and
Caldwell have been based on extensions of historic records. Usually these
extensions are keyed to a logistic "S" curve. This curve is generally
accepted as a typical growth pattern of a community. The historic record
of population, the Series IV-B projections, and the estimated ultimate
population are all plotted as part of a single logistic "S" curve on Fig-
ure V-4. This projection of population is utilized for estimates of
waste water flows for the years beyond the limits of the Series IV-B
projections.
k
V-7
160,000 -
140,000 -
120,000
1960 1970 1980 1990 2000 2010 2020 2030
POPULATION PROJECTION FOR
STUOV AREA
FIGURE V-4
A major difference of approach exists between the CPO staff use of
Series IV-B population figures and the adopted position of Carlsbad. CPO
has taken the assumed population growth for each community and distributed
it within the community in accordance with a number of population control
assumptions. The City, on the other hand, has adopted the position that,
while it agrees with the total number of dwelling units projected by CPO,
it does not feel that these dwelling units can be accurately distributed
throughout the various areas of the City under the control assumptions
utilized. Instead, the City feels that location of population growth will
be decided by market considerations in conformance with the City General
Plan and within applicable zoning restrictions.
The City Planning Department is presently developing projections of
population distribution. Waste water flows utilized in this study are
based on preliminary data obtained from the City staff. The accuracy of
the population data projections are not vital to this study since it is
not proposed to necessarily reclaim and reuse all of the sewage flow
reaching a specific reclamation site, but only that amount necessary to
satisfy anticipated reuse markets. Therefore, lack of precision in pro-
jecting future population distribution should not significantly affect
waste water reclamation planning.
WASTE WATER FLOWS
Based on the foregoing discussion of population projections and
allowing for flow from upstream agencies, waste water flows throughout
the Encina sewer service area can be estimated. Figures V-5 through V-7
show the existing and projected annual average waste water flows at various
locations throughout the area. The flow estimates have been made assuming
a per capita flow of 100 gpd. The value of 100 gallons per day per person
is an assumed average figure. It includes flow not only from actual dwell-
ing units, but a per capita contribution of flow from commercial and other
nonresidential connections. Population distribution as projected by City
staff is assumed for the 1985 flows and General Plan land use was employed
to calculate ultimate flows within the City.
V-9
VISTA 34
MITER STATIONPUMP STATION COPYm I*1*4*1 Culuvcru
BUENA ,-
- STATION
HEOIONDA
L E QENO
EXISTING SEWER
l.S FLOW IN M6D
ENCINA WATER
CONTROL FACILITY
BATIQUITOS
TB-7B \A/ASTE VA/ATER
FLOXA/B IM STUDY AREA
(IIM MOO)
LEUCADIA
PUMP STATIONENCINITAS
PUMP STATION
II II II 1^ J K J L J L i K I L J K J
VISTA
METER STATIONBUENA VISTA
PUMP STATION
COPY
IAGUA HEDIONDAIPUMP STATION
L.EBEIUD
EXISTING SEWER
1.5 FLOW IN MOD
fNCINA WATER
P&LLUTION CONTROL FACILITY SAN MARCOS I
PUMP STATION
BATIQUITOS
PUMP STATION
PROJECTED 1BBB
XA/ABTE WATER FLOWS *
IIM STUDY ARE A (IN MOD)
LEUCADIA
PUMP STATIONENCINITAS
PUMP STATIONHAbLI) ON bl-KHb IV 1) rorui.ATION
I'KOIl ( 1 lONb. (VIIIIOIII
Kl i:i AMATKIIt |'t AN1 S
i
ro
SCAII
BUENA VISTA
PUMP STATION
VISTA
9.1
METER STATIpN ....••••"»»"1111"1
1.3
L-EGEMP
iiiini NEW SEWER
mm MUM EXISTING SEWER
^!'S FLOW IN MGD
C
run*'
JAGUA HEOIONDA
STATION
ENCINA WATER 1O..1
POLLUTION CONTROL FACILITY V SAN MARCOS L^ PUMP STATION!*
OC
PROJECTED ULTIMATE
XA/ABTE XA/ATER FLOVA/S*
m IIM STUPY AREA(llM MGP)
IIASCD UN SAIUKAIION I'OI'IJLATIOHS. ENCINITAS
VVIIIIUin lll'li'l KLAM KLCI.AMATION PUMP STATION
I'l AMIS
IBATIQUITOS
PUMP STATION
1.0
to«|qult»»Logeon _^3Ssf.v
?'f *>
3.1
r LEUCADIA
PUMP STATION
As previously established, projected total agricultural market
potentially available will require 3,000 acre feet of reclaimed water a
year. Thus, during the peak demand month of July, 690 acre-feet of water
will be consumed. This is equivalent to a 7.5 MGD demand. It must be
remembered, however, that only 35% of the total volume of reclaimed water
produced is actually reused. During the winter, most of the water treated
would be discharged to the ocean outfall through the excess effluent con-
nection. Estimates of the volume of waste water available for possible
reclamation at critical points on the sewage collection system are shown
in Table V-2.
TABLE V-2
Waste Water Flows
Availabile for Reclamation
(MGD)
LOCATION
Vista Meter Station
Agua Hedionda Pump Station
Buena Pump Station
San Marcos Pump Station
Batiquitos Pump Station
Leucadia Pump Station
Encina Pump Station
Encina Water Pollution
Control Facility
1978
3.
6.
0.
2.
0.
2.
0.
11.
4
2
5
5
2
0
6
8
1985
4
8
1
3
0
3
1
17
.1
.0
. 5
.8
.3
.0
.0
.6
2005
9
29
4
9
1
3
1
43
.1
.3
.2
.2
.0
.1
.5
.3
The location of the waste water available for reclamation is, for the
most part, upstream of many of the areas of agricultural reuse. This is a
unique situation. Normally, reclaimed water must be transported some
distance to the areas of reuse. In this respect, Carlsbad has an ideal
situation with regard to layout of the reclamation and reuse system.
k
V-13
AVAILABILITY OF SEWAGE FLOWS FOR RECLAMATION
The quantity of water reclaimed at a given location should be based
either on the market potential, or on the size of facility that can be
economically constructed. Since there is a complete sewerage system
serving the study area, it is feasible to plan to extract and reclaim
any portion of the total raw waste water flow arriving at a selected recla-
mation plant site. The remainder of the sewage would then flow to the
Encina facility for treatment and ocean disposal. The fraction of sewage
selected for use could be small or large, depending upon demand in the area
served by the reclamation plant.
This approach has the advantage of introducing a high degree of
flexibility into the planning and operation of reclamation facilities. It
will not be'necessary to base planning upon the total quantities of waste
water being generated in lands upstream from the reclamation plant. Instead,
only that portion of the flow which can be economically handled would be
reclaimed and reused.
It is visualized that reclamation facilities would operate on a con-
tinuous basis, with excess effluent being discharged to the ocean when not
required for reuse purposes.
The capacity of a reclamation plant at a given location will depend
primarily on the anticipated reuse market. However, it is possible that
a plant would be constructed to a larger capacity for purposes of construc-
tion economy, or in anticipation of increases in the reuse market.
Similarly, there is no need to reuse the total output of a satellite
waste water reclamation plant each day of the year. In fact, to reduce the
need for large storage reservoirs, satellite plants may be sized intention-
ally large, as previously pointed out. The unused portion of the reclaimed
water would be discharged to the ocean through the excess effluent lines.
For the purposes of this study, treatment plants are sized to meet the peak
monthly irrigation demand without requiring supplemental water from storage.
In agricultural irrigation, approximately 23% of the total annual water
demand usually occurs in July.
V-14
REUSE MARKETS
The following analysis of reuse markets within the study area indicates
that the greatest need for reclaimed water is for irrigation purposes. In
the early years of the program, existing agricultural water uses will pre-
dominate. Agricultural demand will be supplemented and eventually could
be replaced by a growing reuse market for landscape irrigation. Data
developed in the following sections of this study indicate that the land-
scape irrigation market will eventually be greater than the present agri-
cultural use of irrigation.
This chapter contains an analysis of the existing agricultural market
in the study area based on lands presently utilized for agricultural pur-
poses, or suitable for long-term agricultural use. Agricultural land use
in Carlsbad is subject to a number of pressures which could result in its
phasing out over the years. In the future, consideration must be given to
the existence and development of other markets, such as landscape
irrigation on public and quasi-public lands, and industrial use.
For the purposes of this study, the reuse market for the first phase
of the recommended reclamation master plan is based on the presently avail-
able agricultural land within the study area, plus whatever new urban
landscape irrigation market may develop by 1985. The reuse market for
the ultimate development of the reclamation and reuse system has been
estimated for the year 2005, based primarily on new urban development
needs. Adoption and implementation of the recommended master plan would
not require perpetuation of agricultural land uses, nor would it encourage
phasing out of such uses. The plan is intended to be designed in such a
manner that accommodates any combination of agricultural and urban land
uses, ranging from existing conditions to the ultimate General Plan
condition of no agricultural acreage.
Recommendations regarding preservation and maintenance of agricultural
land are presently under study by City staff. These decisions could be
adopted and implemented independently of the reclamation master plan.
The existence of a supplemental source of irrigation water may possibly
affect decisions regarding the maintenance of agricultural areas.
V-15
The relative importance of these markets over the years is illustrated
in Figure V-$ which shows total water use for domestic consumption, land-
scape irrigation, and agricultural irrigation. While agricultural
irrigation demand will constitute the initial market for reclaimed
water, Figure V-8 clearly demonstrates that landscape irrigation of
urban lands will be the primary long range market. As the City of
Carlsbad continues to urbanize, landscape irrigation will become increas-
ingly important consumer of potable or reclaimed water.
Thus, a substantial market opportunity for reclaimed water already
exists. It will be necessary to convert considerable acres from the use
of potable water to reclaimed water. This endeavor will take an active
marketing program, possibly accompanied by financial inducements and
regulations favoring use of reclaimed water. Activities necessary to
"establish agricultural reuse—of~ reel aimed water will be one of the major
implemention steps in the recommended reclamation master plan.
As one possible financial inducement, availability of reclaimed
water for irrigation purposes at prices below present prices for potable
water might generate interest in new agricultural activity within the
study area. Growing of fodder crops is an example of an agricultural
activity which is marginal at present, but which might be developed suc-
cessfully with a slight shift in some of the economic factors. Changes
of this nature would tend to increase the potential agricultural market
o.r" and above that indicated by past activity.
The inventory of agricultural land prepared by the City staff
identified several classes of land based on their suitability for long-
term agricultural use. These classifications would be of interest to a
reclamation project if specific areas were to be purchased and reserved for
agricultural use. However, the recommended reclamation master plan
constitutes a broad approach, without specific recommendations and land
reservations. For this reason, the recommended reclamation master plan
will not be seriously impacted by specific agricultural land use decisions.
Conversion of agricultural land to other uses such as residential develop-
ment, would not affect the outcome of this change, since the recommended
reclamation master plan will not be based on a fixed agricultural market.k
V-16
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
40,000 n
£ 3O,OOO-
HI
jj 20,000-
10,000
0-
DOMESTIC
CpNSUMPT
(1)
197O 1980 1990
III I
2000 2010 2020
YEAR
(1) PROJECTION BASED ON 1OO GAL/DAY/PERSON
(2) PROJECTION BASED ON .13 AC-FT/YEAR/PERSON
STUDY AREA WATER USE
V-17
FIGURE V-8
Urban Markets
At the present time, there is no irrigation of landscaping, parks,
or other urban areas in Carlsbad with reclaimed water. Once a source of
reclaimed water is available, it is visualized that the City would wish
to make maximum use of reclaimed water for irrigation of such areas.
Table V-3 shows the anticipated acres of various types of urban land
that could become available for urban irrigation over the years.
TABLE Y-3
ESTIMATED URBAN LAND
AVAILABLE FOR IRRIGATION
(Acres)
YEAR
1985
1995
2005
2015
NEIGHBORHOOD
PARKS
0
200
400
600 '
MAJOR
PARKS
0
500
1000
1500
GOLF
COURSE
0
0
200
' 400
SCHOOL
GROUNDS
0
100
300
500
RESIDENTIAL
OPEN SPACE
0
900
1300
2100
TOTAL
0
1700
3400
5100
Upon full development of urban areas indicated by the General Plan,
it is envisioned that reclaimed water will be used primarily in urban
markets for landscape irrigation. As already pointed out, to accomplish
this objective it will be necessary for the City of Carlsbad to require
installation of dual water systems in many of the new residential and
commercial developments.
Public health regulations do not now permit use of reclaimed water at
individual households. However, the regulations do permit reclaimed water
to be used for irrigation of public and quasi-public lands, such as golf
courses, schools, public open space and parks in residential and condo-
minium developments. Table V-4 shows a breakdown of all possible uses of
reclaimed water within a typical low-medium density development. If only
the greenbelts in the area were irrigated with reclaimed water, approxi-
mately 0.45 acre feet per year of reclaimed water can be used on each
gross acre of residential development. If neighborhood parks and other
V-18
such land are included in the irrigation program, it is reasonable to ex-
pect that on the average about 0.7 acre feet per year of reclaimed water
would be consumed per gross acre of new developed urban lands. This
figure is based on the assumption that approximately 8% of the gross urban
acreage will be under irrigation. This is the unit rate of consumption
which is used to determine total urban reclaimed water demand in this
study.
TABLE V-4
WATER USE IN RESIDENTIAL AREA
LAND USE
Greenbelt
Streets
Houses & Driveways
Yards
TOTAL
.__..2 CONSUMPTIONAREA
(ACRES) USE OF WATER ACRE FEET/YEAR GALLONS PER DAY
.15 Irrig?tion .45 402
.25 None
.09 Indoor Use .75 670
(To Se«er)
.41 Irrigation 1.23 1,098
1.00 2.43 2,170
Average 2.5 Houses/Acre 3270 Gallons Per Day
Estimated by Rick Engineering Company
N'ote: Irrigation Rate « 3 Acre Feet/Irrigated Acre/Year
Thus, the 9100 acres slated for urban development in Carlsbad could
theoretically consume 6400 acre feet of reclaimed water per year. It
is unlikely that a reclaimed water system will be installed to serve every
acre of newly developed residential lands. In addition, some of the
larger open space areas and parks will probably be left in ther native,
unirrigated condition. Based on experience in the Irvine Ranch Water
District which presently has a program for the installation of dual water
supply systems, it is estimated that the actual ultimate urban demand will
be approximately 75% of the theoretical demand, or 4,800 acre feet per year.
k
V-19
It is interesting to note, with respect to use of reclaimed water
in urban areas, that a typical acre of residential-low/medium zone
will produce an average of 0.8 acre feet per year. From this, it can be
seen that the requirements for landscape of sewage irrigation will absorb
almost 87.5% of the waste water produced in that same area. The land-
scaping needs discussed are those required in order to conform with the
regulationsof the City Planning Department.
The potential market for landscape irrigation in urban areas could
be expanded considerably by the construction of a second water distribution
system in presently-developed areas. However, retrofitting would be
expensive relative to the amount of reclaimed water utilized. An order
of magnitude cost estimate of a typical retrofitting project is given
in Table V-5. This indicates that the additional capital cost required
to utilize reclaimed water would be approximately $2600 per acre. Using
the previously established value of 0.45 acre feet of irrigation water
per acre per year, it can be calculated that a cost differential of
$1,000 for reclaimed water over potable water would be necessary in order
to recover the capital costs within a period of ten years. On this basis,
it does not appear that retrofitting will be adopted for purely economic
reasons. If, in the future, the potable water supply should become
as critical as anticipated, substitution of reclaimed water for potable
water may be the only means by which green areas and parks can be
irrigated. At that point in time, the cost calculations discussed above
might become more attractive.
Another use for reclaimed water would be through the creation of new,
or "retrofitted", fire distribution pipelines, utilizing reclaimed water.
Many older cities in the East still employ separate water supplies from
rivers for fire-fighting purposes. Since fire supply normally dictates the
size of water distribution mains and storage reservoirs there would be a
considerable saving in the construction of the potable water system. How-
ever, preliminary calculations indicate that the overall cost of utilizing
reclaimed water for fire-fighting purposes would be considerably greater
than a continuation of present practices. There may be a very short-term
high demand; however, in the overall, the demand for reclaimed water for L
j
V-20
fire-fighting purposes is small, and a large distribution system made up
of large pipes is necessary to distribute the water to meet fire flow re-
quirements.
TABLE V-5
COST ESTIMATE -.
RETROFIT FOR DUAL WATER SYSTEM*
1. 4,000 Lineal Feet 8" Diameter Main
3520.00
2. Relocate Connections at Irrigated Areas
20 Each 9 5500.00
3. Testing Stations
4. Signs L.S.
5 Each 9 31,000.00
Engineering
Contingencies
Testing
•5 30,000
= 10,000
5,000
• 5,000
5100,000
TOTAL 5130,000
Average Cost * 52,600/Ac.
» S 650/E.D.U.
'Assume "Typical" 50 Acre Urbanized Area -
4,000 Feet of Street, 200 Homes
Park Areas
There are three major parks contemplated for the study area. Although
none of these are being actively designed at this time, they are all con-
tained in long-range thinking of various planning agencies in the county.
The approximate location of the projected parks are shown in Figure V-9.
Contacts with County of San Diego Parks and Recreation Department staff
indicates that the current tendency is to keep park land in a natural,
unirrigated condition. Therefore, the proposed major parks may not
constitute a major market. However, should irrigation water be required
for parks, reclaimed water could be provided easily once the facilities
proposed in the recommended reclamation master plan are constructed. It is
V-21
CARLSBAD
LAKE CALAVERA
REGIONAL PARK
AGUA HEDIONDA
CITY PARK
L E G E IMD
PROPOSED PARK
• •- STUDY BOUNDARY
BATIQUITOS
REGIONAL PARK
PROPOSED FUTURE
also possible that, if reclaimed water should provide an inexpensive source
of irrigation water, the present trend may be reversed and parks may
constitute a larger potential market than presently anticipated.
Industrial Reuse Markets
The San Diego area has historically been dependent upon imported
water for the greater part of its supply. Consequently, there has never
been an abundance or surplus of water in the area. This has mitigated
against the establishment of any large water-using industry in the past.
The same situation will exist in future years. Cost of water in San Diego
County generally inhibits the development of major water-using industrial
complexes, either in the County or within the study area. It is, of course,
possible that some "wet" industrial plant might locate in the study area
if a suitable water.supply of^reclaimed water could be assured. However,
such decisions would result from site studies by individual firms and are
not subject to prediction at this time. Therefore, potential industrial
reuse is not presently a quantifiable factor in planning a reclamation
program for Carlsbad.
The type of industry presently existing in the City does not lend it-
self to large scale water consumption. Thus, for planning purposes, no
substantial industrial reuse is included in calculations of reclaimed
water markets made in this study. Nevertheless, reuse of reclaimed water
by industry should be encouraged in every way possible. One obvious
approach is to provide reclaimed water as inexpensively as possible to
industrial areas and to promote use of this water wherever possible.
Availability of a source of reclaimed water might provide an inducement
to an industry considering relocation or expansion in Carlsbad.
Should a substantial industrial reuse market develop, reclaimed
water could be supplied by expansion of the facilities in the recommended
master plan or by reducing volumes available for other uses. Production
capacity in the recommended reclamation master plan will be based upon
size of existing and readily predictable agricultural markets. However, it
would be possible to make available greater quantities of reclaimed water
oy increasing the capacity of reclamation plants or increasing the volume <J
V-23
of storage facilities, as already explained. As an extreme example, the
entire sewage flow to the Encina plant, estimated to reach 18 MGD by the
year 1985, might be converted to industrial use.
Examples of industrial uses to which supplemental reclaimed water
could be put are shown in Table V-6. Also shown there are the advanced
treatment steps that would be required to produce the quality of water
necessary for the various uses. The additional treatment steps would pre-
sumably be provided by the industry, although, if the pricing structure
were properly arranged, the additional treatment facilities could be
installed at the reclamation plant at the expense of the City, with the
extra cost passed on to the industrial user. It should be noted that use
of reclaimed water for food processing and related activities would not be
acceptable.
TABLE V-6
POTENTIAL INDUSTRIAL USES
USE
1. Cooling water
(Single Pass)
2. Cooling Water
(Multiple Pass)
3. General Hash Down
Uses - Minimum
Human Contact
4. Hash and Cleaning
Uses With Human
Contact
5. Process Water
General Use
6. Plating Process
7. Aesthetic Ponds
s Fountains
*In Addition to Secondary
ADVANCED*
TREATMENT
REQUIRED
None
Demineralization
None
Coagulation ,
Clarification,
& Filtration
Filtration
Filtration s
Demineralization
Filtration
TYPICAL**
QUANTITY
500,000 GPD
100,000 GPD
50,000 GPD
10,000 GPD
200,000 GPO
100,000 GPD
50,000
Treatment and Disinfection.
**3ased on Industry Employing 200 Persons.
1
M
k "IJ
V-24
Highway Landscaping
Another potential reuse market is irrigation of landscaping along
the major highways in the area. The market is fairly minor. It is
estimated the total area of irrigated land adjacent to freeways within the
study area is less than 100 acres. For convenience, this demand has been
included in the total urban market as landscape irrigation.
ESTIMATED MAGNITUDE OF RECLAIMED WATER MARKET
As previously indicated, during the initial development period, the
reclaimed water system will serve mainly agricultural markets. With a
strong marketing program, an agricultural market of 3,000 acre feet per
year could be developed by the mid-1980's. In time, agricultural demand
could diminish as urban development occurs in accordance with the City
General Plan. Ultimately, the urban demand is expected to reach 4,800
acre feet per year. In the intervening years, the reclaimed water market
will be a mix of both agriculture and urban markets. Figure V-10 is an
estimate of the reclaimed water market demand over the years. Agricultural
demand is based on water sales by Carlsbad Municipal Water District. Depth
of irrigation is derived from total annual water sales divided by the total
area classified as agricultural. Total demand is the product of depth of
irrigation times the total area of agricultural land available for irriga-
tion in any year. Urban demand is based on total urban area being irriga-
ted multiplied by 0.7 acre feet per acre.
The data presented demonstrates that if the agricultural demand were
to decrease to zero as the result of urbanization, overall reclaimed water
demand could increase from 3,000 acre feet per year to almost 5,000 acre
feet per year to satisfy potential requirements for landscape irrigation
water. This assumes that all new urban development will be provided with
double water systems, and that the City will pursue a policy of requiring
landscape irrigation with reclaimed water.
k
V-25
1
M
-
5000
4000 -
m >- 3000 .
2000 .
1000 -
1980 1985 1990 1995 2000 2005 2010 2015 2020 2025
UPEND YEAR
AGRICULTURAL DEMAND
URBAND DEMAND
PROJECTED RECLAIMED WATER USE
FOR STUDY AREA
FIGURE V-10 k
V-26
FLOWS FROM UPSTREAM AGENCIES
All other member agencies of the Encina Joint Powers group are up-
stream from the City of Carlsbad and discharge their waste water via inter-
ceptor sewers which pass through the City. These agencies are Vista Sanita-
tion District, the Buena Sanitation District, San Marcos County Water Dis-
trict, Leucadia County Water District and Encinitas Sanitary District. If
needed to satisfy irrigation demands, at least a portion of the flow from
these agencies could become available for reclamation and reuse in Carlsbad,
provided that agreements could be reached between the affected parties. It
is difficult to anticipate the quantity of waste water that might be in-
volved in an interagency reclamation program, since upstream agencies may
wish to practice reclamation and reuse within their own borders. For
example, Leucadia County Water Distrfclrahd San Marcos County Water District
are proceeding with waste water reclamation programs of their own. while
the opportunity to reinstitute waste water reclamation at Ecke Ranch in
the Encinitas Sanitary District still exists.
Discussions with the staffs of the various districts indicate that
planning for reclamation within their own borders will reduce the flows
available to Carlsbad significantly. The anticipated amount of such recla-
mation activity within each district is shown in Table V-7. The remaining
flow will continue to be conveyed to Encina as raw sewage and could be made
available to Carlsbad for reclamation purposes. The available flow will be
included in the planning of reclamation plants discussed in the following
chapters.
V-27
TABLE V-7
ANTICIPATED RECLAMATION PROGRAMS
OF UPSTREAM AGENCIES
MEMBER AGENCY PROGRAM DESCRIPTION
QUANTITY OF
RECLAIMED WATER
(MGD)
Buena Sanitation District
Vista Sanitation District
San Marcos County Water
District
Leucadia County Water
District
Encinitas Sanitary
District
Landscape Irrigation at
Shadow Ridge Development
Reactivation of San Marcos
Plant with Landscape Irri-
gation
Reactivation of Leucadia
Plant with Golf Course
Irrigation
New Plant with Landscape
Irrigation
-Plant and Irrigation at
Ecke Ranch
TOTAL
1.0 MGD
0.6 MGD
0.75 MGD
RECLAMATION ACTIVITIES BY OTHER AGENCIES
At the County of San Diego level, interest in reclamation programs has
been demonstrated by the formation of the San Diego Region Water Reclamation
Agency. This group was established to investigate and develop innovative
methods of reclaiming and reusing waste water.
In addition, the County of San Diego and the City of San Diego are
joint sponsors of the San Diego Water Reuse Study. The two agencies are
using federal and state grants and their own funds to conduct planning
of a number of reclamation projects throughout the County.
The San Diego Water Reuse Study is part of the EPA Clean Water Grant
Program and is being carried out under Section 201 of Public Law 92-500.
This section of the law covers detailed planning of specific projects.
Reports prepared under Section 201 are intended to be final planning docu-
ments that can be utilized for the start of final design. In this respect,
the reuse study is not a review of the feasibility of reclamation, nor is it
a regional planning effort. That effort was accomplished in the Section 208
Areawide. Water Quality Management Plan prepared by CPO. Technically, the
V-28
output of the reuse study will consist of specific proposals for the con-
struction of specific reclamation projects.
Reclamation activities in surrounding sewering agencies have also
been evident in the past year. The Leucadia County Water District (LCWD)
has recently received permission to reactivate its existing waste water
plant at a capacity of 0.75 million gallons per day (MGD). In addition,
LCWD proposes to construct a new satellite plant with a capacity of 2.75
MGD in order to provide additional sewerage capacity and reclamation
potential with their service area.
The San Marcos County Water District (SMCWD) is also reactivating
and expanding its treatment plant up to a capacity of 0.6 MGD. Reuse by
landscape irrigation will be practiced in the San Marcos County Water Dis-
trict area. _ - - -
The Buena Sanitation District (BSD), which is operated by the San
Diego County Department of Sanitation and Flood Control, is considering
the construction of a new satellite plant within its service area. This
would be funded by the DAON Company, developers of a considerable acreage
within that district.
When viewed in the perspective of planning activities by other
agencies, it can be seen that their efforts do not duplicate the City of
Carlsbad's master planning program. In fact, the San Diego Water Reuse
Study may be considered the next procedural step toward applying for federal
and state construction grant funds for waste water reclamation facilities,
should that be the City's desire. Establishment of a master plan by the
City will permit integration of the output from the Reuse Study into the
City's reclamation planning efforts.
V-29
CHAPTER VI
COMPARISON OF REGIONAL
AND SATELLITE WASTE WATER
RECLAMATION PROGRAMS
GENERAL CONCEPT
This chapter describes and compares satellite reclamation systems
and regional reclamation systems. Discussion of the various items will
provide background for development of specific projects described in the
following chapter.
A satellite program, as developed in this study, would incorporate
three basic phases. Phase 1 would be construction of essentially in-
dependent reclamation facilities, each with its own distribution piping
and designated irrigation area. The intermediate phase would involve
joining of these previously independent systems into a partially integrated
system, with some of the facilities modified to serve more than one
reclamation plant. The final phase of the satellite concept would be
achieved when all of the reclamation facilities are completely integrated
into a reclaimed water distribution system, which would also serve for
discharge of excess effluent into the ocean.
Storage facilities, either aboveground or in subsurface aquifers,
would be connected to the distribution piping system so that all of the
reclamation plants can share common storage. In the latter two phases
of the satellite program, it is anticipated that reclaimed water would be
provided to customers on a "demand" basis. The distribution piping system
would eventually•permit flow from each of the satellite plants to all
points of the system. A piping connection from the distribution system to
the Encina ocean outfall would provide an excess effluent line, in lieu of
the "fail-safe connection" required for an independent satellite facility.
The pipe network can thus serve two purposes, distribution of reclaimed
water and discharge of excess effluent to the ocean.
The regional concept as applied to Carlsbad would provide a single
major reclamation plant near the existing Encina Water Pollution Control
Facility. An examination of the master plan for Encina indicates that
there will not be sufficient area available on the present site for the
necessary advanced waste treatment facilities required for reclamation.
It would therefore be necessary to provide additional land adjacent to the
existing facility. A major pumping station would be required to pump the
reclaimed water back upstream to the areas of reuse, which have previously
been discussed.
The distribution piping layout would be essentially the same for
both concepts. However, in the case of the satellite concept, flow
would be at least partially by gravity from the satellite plants, down
toward the ocean. On the other hand, the flow from a regional plant would
be under pressure back upstream. There would be a considerably greater
power requirement for the regional facility due to this necessity for
additional pumping.
Major storage facilities and distribution storage facilities in the
reuse area will be similar for both concepts. As previously explained, lack
of economic storage sites will minimize the amount of long-term storage that
will be provided for either concept. Diagrammatic illustrations of the two
concepts are shown in Figure VI-1 and Figure VI-2.
COST COMPARISON OF SEPARATE AND REGIONAL CONCEPTS
Order of magnitude cost estimates can be performed for economic com-
parison of the satellite and regional concepts. While not exact, such cost i
estimates provide a useful tool in comparing construction and operating costs
of alternative projects intended to accomplish the same end result. Where
reclamation of waste water is planned, order of magnitude cost estimates can
be employed to arrive at the approximate cost per unit of reclaimed water
for each alternative system under consideration. Since reclaimed water
pricing normally is a critical consideration in feasibility of a planned
reclamation project, comparative unit costs give valuable insight on
relative economic viability among several alternatives under consideration.
VI-2
/ R R IGA TION
STORAGE
-^RESERVOIR
DISTRIBUTION
PIPE
WASTE WATER REGIONAL
TREA TMENT PLANT
7SATELLITE CONCEPT
STORAGE
RESERVOIR
IRRIGATION
oc
m
<
KJ
COLLECTION
SEWERS
COLLECTION
SEWERS
REGIONAL
TREA TMENT PL ANT
RECLAMATION
PLANT
REGIONAL. CONCEPT
Although the following analysis is devoted to economic costs of var-
ious reclamation alternatives, the selection process should not be based
exclusively upon economics. Social and environmental considerations are
matters of major importance, which are dealt with in the environmental
impact report.
A precise estimate of construction and operating costs would require
detailed planning and engineering beyond the scope of this study. However,
it is possible to examine recent cost trends to establish order of magnitude
estimates. Table VI-1 presents an example cost comparison between a single
regional plant with a reclaimed water capacity of 6 MGD and a system of four
1.5 MGD satellite plants. Minor cost figures which are common to both con-
cepts have been omitted. The comparison indicates that, in the example
instance, there is a difference of approximately $6 million for construction
of facilities under the two differing concepts.
TABLE VI-1
TABLE OF COSTS
CENTRAL RECLAMATION PLANT SATELLITE RECLAMATION PLANTS
COMPONENT COST COMPONENT COST
6 MGD SECONDARY TREATMENT
PLANT EXPANSION
6 MGD ADDITION OF CHLORINE
AND FILTRATION FACILITIES
6 MGD DEMINERALIZATION
FACILITIES
15 MILES - 12-INCH DISTRIBUTION
MAINS
10 MILES - 36-INCH TRUNK SEWERS
30-DAY STORAGE RESERVOIR
CAPITALIZED COST FOR PUMPING
TOTAL
ENR INDEX » 3300
11.8
2.7
5.0
2.5
2.2
2.7
0.7
FOUR 1.5 MGD SECONDARY
TREATMENT PLANTS
15 MILES - 12-INCH
DISTRIBUTION MAINS
5 MGD DEMINERALIZATION
FACILITY
FOUR 1.5 MGD CHLORINE
6 FILTRATION FACILITIES
FOUR 30-DAY STORAGE
RESERVOIRS
17.2
2.5
5.4
3 .6
BEST
COPY
VI-5
The above cost estimate involves a large number of simplifications
and assumptions. Estimated operating costs have not been included, nor has
the cost per acre foot of reclaimed water been projected for each alterna-
tive. However, the example illustrates that construction costs alone may
not be the most significant factor in selection of a reclamation alterna-
tive. Reclamation alternative costs given in Table VI-1 include all
capital costs and the capitalized additional cost of pumping from the
regional plant back to the areas of reuse.
A complete comparison between the two concepts would include energy
costs, operation and maintenance costs, and applicable financing costs.
Power costs for secondary treatment will be approximately the same re-
gardless of location. The extra pumping requirements for the regional
concept have been reflected in the capital cost figures. Other pumping
costs are assumed to be identical.
Estimates of operation costs were prepared in the "Overview Report".
These indicate that costs at a typical satellite plant would be approxi-
mately $640 per million gallons treated. Additional cost for deminerali-
zation was estimated to be $600 per million gallons. Cost for treatment
at Encina was estimated to be $670 per million gallons after construction
of Encina, Phase III. However, this was based on estimated service
charges and is felt to be on the high side. Cost figures obtained from a
number of secondary plants in Southern California indicate a range of
from $450 to $550 per million gallons. For purposes of this study,
operation and maintenance costs are estimated to be as follows:
Satellite Plants
Satellite Plants
Secondary $ 650/million gallons
Demineralization $ 60Q/mil1ion gallons
Satellite Plants - Total $l,250/nrillion gallons
Regional Plants
Regional Plants
Secondary $ 600/million gallons
Demineralization $ 600/million gallons
Regional Plants - Total $1,200/million gallons
VI-6
The normally expected economics of scale will not be as great for
the satellite plants contemplated for Carlsbad, since there will be a
number of plants in operation, thus permitting sharing of personnel and
equipment.
These estimates result in an annual cost of $2.7 million for the
satellite system and $2.6 million for the regional system. Here again,
as in the case of the capital cost comparison the satellite concept is
estimated to be slightly more costly than the regional concept.
Financing and interest charges do not enter into the type of compari-
son being considered here. They are dependent on the source of funds
and the identity of the borrower. This comparison is based on 1980 total
costs with no consideration of funding source, inflation, or actual time
of construction.
The matter of the source of funding has another aspect. If the com-
parison were to be made on a normal "cost effectiveness" basis, the source
of secondarily treated waste water at Encina following the construction
of the Phase III expansion would provide more effluent than could be
utilized by the potential reuse market. The construction of additional
facilities at satellite plants would be redundant at this time. However,
when it is considered that the satellite plants would probably not be
constructed with city general funds and that additional treatment capacity
will be required by Carlsbad in the future, the seeming duplication of
capacity becomes simply a matter of timing. In essence, the capacity at
the satellite plants would be constructed at an earlier date with alternate
sources of funding.
COST OF PUMPING
The cost comparison shown above includes an item listed as "capital
ized cost of pumping". This item reflects the additional cost that must
be borne-by the centralized system to reflect the fact that the reclaimed
water will have to be pumped back upstream to the points of reuse. It is
recognized that pumping facilities will also be required at the satellite
VI-7
plants to produce pressures necessary to distribute the reclaimed water to
the areas of reuse. However, there will be an additional cost to the
centralized system for pumping effluent the additional 200 to 300 feet
back up to the elevation of most of the satellite plants. The cost item
included to reflect this fact is based on pumping 50% of the reclamation
plant capacity to a height of 250 feet, at a cost of seven cents per
kilowatt-hour. This annual cost is capitalized at an interest rate of
8%, giving a present worth capital cost of $700,000 to be assessed against
operation of a central waste water reclamation plant.
EASE OF IMPLEMENTATION
The satellite concept is more adaptable to phased construction than is
the regional approach. Implementation would be by means of a number of
independent projects. Each individual satellite plant could be constructed
in phases as funding becomes available. The satellite concept thus lends
itself more readily to funding in smaller increments. This is an approach
that could utilize developer contributions more readily than a single large
project.
On the other hand, the regional concept implies establishment of a
single large system at the outset of the program. In order to develop a
working reclamation and reuse program the central reclamation plant would
most economically be planned and constructed as a single unit. Similarly,
all of the reclaimed water distribution lines upstream of the areas of reuse
would have to be constructed at one time. Thus, this concept lends itself
to a single project which would presumably be financed from a single
source.
A case in point with regard to ease of implementation exists in a
comparison between the time already expended in planning and designing
of the Encina Phase III expansion and the time required to process
approvals for the Lake Calavera Hills reclamation plant. Several years
have already been spent at Encina, while the Lake Calavera Hills facility
was ready for design within a little more than one year after it was con-
ceived in its present form. Experience at Leucadia in the rehabilitation
VI -3
of their existing plant and a similar project for San Marcos are other
illustrations of the manner in which small reclamation projects can more
ahead with relative ease.
The most immediate short-term benefit of the satellite concept is
that it can be implemented on an incremental basis and the facilities
placed in operation within a minimum period of time. Reclaimed water could
be available for reuse at a typical small satellite plant in approximately
one year following a decision to proceed.
SHORT-TERM AND LONG-TERM DISADVANTAGES
The principal long-term disadvantage of the satellite concept is the
possibility of planning and constructing facilities at a location where
they will not be suitable for changing reuse markets. Conversely, a
centralized plant would be built at only one location and, hence, there is
even less flexibility.
Long-term planning for the Encina Water Pollution Control Facility
contemplates an ultimate sewage treatment capacity of 45 MGD. However,
flows of this magnitude are not projected within the time period used
in this study. For purposes of this report any capacity provided at
satellite reclamation sites would be necessarily deducted from the flow
at Encina. Thus, a potential disadvantage of the satellite system could
arise if Encina were actually constructed to the 45 MGD maximum, and
duplicate satellite treatment capability were also provided. Such dupli-
cation may be avoided simply by not expanding Encina above the capacity
reauired when treatment capacities of satellite plants in the region are
taken into account. Implementation of the satellite concept would there-
fore reduce the ultimate planned capacity of the regional treatment plant
under present population projections.
Since it constitutes essentially a single project approach, once a
central reclamation system is initiated it can not be cut off without con-
siderable financial loss. A satellite program, on the other hand, can
k
VI-9
be readily stopped at any point in its development without accruing sub-
stantial fiscal losses.
CONCLUSION
Information presented in the preceeding sections indicates that the
satellite concept is preferable to a centralized approach in planning for
major waste water reclamation in Carlsbad. Although cost factors of the
regionalized approach give evidence of being more favorable than those of
the satellite concept, the differential is not significant. It is on the
order of 10%. The relative ease of implementation of the satellite pro-
gram on an incremental and phased basis makes it preferable in that it
can be started almost immediately without the use of public funds. The
satellite concept therefore lends itself more readily to the basic
assumption inherent in this study, which is that a reclamation and reuse
program is desirable and should be implemented with maximum speed and
with minimum public expenditure.
k
VI-10
CHAPTER VII
ANALYSIS OF INDIVIDUAL
SATELLITE WASTE WATER
RECLAMATION SYSTEMS
INTRODUCTION
This chapter is devoted to a discussion of specific reclamation plants
under consideration for the recommended reclamation master plan. The
facilities discussed are those which would be constructed in the first
phases of the program when each reclamation plant and its local distribution
facilities would be essentially a separate independently operating system.
Review of potential reclamation plant sites in Carlsbad best starts
with those described in the Overview Report. Ten suggested projects were
presented at that time. For this study the entire Carlsbad area was re-
viewed once more to determine if there were any other locations which might
be suitable for reclamation plants and reuse facilities. It was determined
that the sites originally listed in the overview report remain the most
viable selections. It was therefore unnecessary to add any sites to the
previous list.
There have been a number of developments affecting the overview pro-
jects. These include the implementation of some of the projects originally
discussed and the lessening of interest in others. A presentation of the
present status of each of the projects in the overview report is contained
in Table VII-1.
The following sections deal with the facilities recommended for each
of the reclamation plants included in the recommended reclamation master
plan.
k
TABLE VI1-1
OVERVIEW REPORT PROJECTS
Present Status
f\3
Number
1
2
3
4
5
6
7
8
9
10
"Reclamation
'•Included 1n
Designation
Buena Vista
Vista
Agua lledionda
Lake Calavera Hills
Encina
Buena
San Marcos
Batiquitos
Leucadia
La Costa South
Comments
Market potential not firm.
VSD not planning reclamation at this time.
Growth pressures reducing market
potential.
Under design by private developer.
Delayed pending expansion of Encina plant.
May not be required as separate entity.
May be replaced by proposed major
Palomar Airport reclamation plant.*
May be replaced by proposed major
Palomar Airport reclamation plant.*
Specifically requested by several land developers.
Already implemented by Leuadia County
Hater District.*
Developments there are served by larger
Leucadia County Water District satellite
plant proposal.*
Present Status
Defer until future.**
Defer until future.
Marginal need.
Assume already implemented.**
Defer until Encina expan-
sion completed.**
Consider part of airport
project.**
Consider part of airport
project.**
High priority.**
In operation.
Under design by Leucadia
County Water District.
plant proposed within district,
recommended reclamation master plan.
L J I J t J I, J I J I J t J L J t J i. J LI i, J t J
BAT1QU1TOS RECLAMATION FACILITY
Location
The Batiquitos reclamation facility would be located so as to provide
reclaimed water to agricultural areas lying northerly and westerly of
Batiquitos Lagoon. Waste water flows would be generated in existing and
proposed residential developments within the area to the north and east of
the facility. Features pertaining to the Batiquitos reclamation facility
are shown in Figure VII-1. The various items shown in Figure VII-1 will be
discussed in the following sections.
The service area for this facility is confined to areas north of
Batiquitos Lagoon. The areas to the south and east of the lagoon are pre-
sently served by Leucadia County Water District. Programs for reclamation
and reuse of waste water are being implemented by that agency within its
boundaries.
There is a proposed County regional park located on the north shore
of Batiquitos Lagoon. Land is presently being acquired for park purposes
by San Diego County. The regional park could constitute a market for re-
claimed water in the future if landscape irrigation is incorporated into
the park planning.
Suggested Plant Sites
A field examination of the area indicates that there are several sites
which offer possibilities for locating a reclamation facility within a 1000
meter radius. These are discussed below in a general way in order to in-
dicate some of the advantages of the individual sites.
The most obvious location for a reclamation site would be in the vicin-
ity of the existing waste water pumping station north of Batiquitos Lagoon.
This site has the advantage of being located directly on the existing North
Batiquitos sewer line at a point where all flow would reach the plant by
VI1-3
ENCINA
TREATMENT
PLANT
„ E 6 E N D
AGRICULTURAL
MARKETS
SITE SELECTION LIMITS
TREATMENT PLANT
LCWD PUMP
STATION
MAJOR TRANSMISSION
LINES
LCWD TRANSMISSION
LINE
|
BAT I QUIT OB PLANT
PHASE 1 (10BS)
gravity. A plant located on this site would be in close proximity to the
Covington Brothers development and its reuse needs. A disadvantage of this
site is that it would be located in a very visible area, both from the new
development and from the freeway. This would necessitate aesthetically
pleasing construction involving extra expense. The limited amount of land
available for a treatment plant would require compact design, which also
tends to increase the cost.
Another potential location for the Batiquitos facility would be in
the agricultural area to the west of Interstate 5. A treatment plant at
this point could be located on a less exposed land that would not require
as much aesthetic treatment. An advantage of the site is that it would
be closer to areas of agricultural reuse.
A third possible site would be in the center of the agricultural
reuse area to the north of Batiquitos Lagoon. This site is similar to the
second since it is located close to an area of agricultural reuse. Once
again, the larger area available for construction would require less con-
struction cost.
All of the sites discussed above are located within the coastal zone,
and would have to obtain approval of the State Coastal Commission prior-to
construction. The facilities will serve essentially only existing develop-
ments and the Covington development, which has previously received a
Coastal Zone Permit. Therefore, the question of development within the
coastal zone being encouraged by the proposed reclamation facility should
not become a part of the Coastal review. It is anticipated that the only
questions raised will concern the construction site itself. Concerns
within that limitation can be satisfied by proper esthetic treatment.
Waste Water Quality and Reclaimed Water Quality
Waste water reaching the Batiquitos plant would be domestic waste from
existing and proposed homes in the area. Anticipated quality of the waste
water and the reclaimed water following secondary treatment is shown in
VII-5
Table VII-2. Test data from the Green Valley Trunk Sewer in the Leucadia
County Water District system is utilized as a basis for the raw water
quality. Characteristics of the waste water found there indicate a need
for demineralization for irrigation of areas east of Interstate 5. From
this table it can be seen that the reclaimed water would be suitable for
general use west of Interstate 5, but that demineralization would be re-
quired in order to use it on lands subject to TDS restrictions east of
Interstate 5.
TABLE VII-2
BATIQUITOS ANTICIPATED RECLAIMED
WATER QUALITY
CONSTITUENT
Biochemical Oxygen
Demand
Suspended Solids
Total Dissolved
Solids
Total Phosphorus
Total Nitrogen
WASTE
WATER
(mg/11
200-
250
800131
10
30
BASIC IJ";
RECLAIMED
WATER
(mg/1)
30
30
300
10
20
TREATED1 '
RECLAIMED
WATER
(mg/1)
5
0
500
1
5
(2) Advanced Treatment Including Demineralization
(3) Assumes Blended Water Supply
Potential Waste Water Flows
Waste water flows that can be utilized for reclamation would be from
existing and planned residential developments in the area. Two major trunk
lines traverse the general area where the Batiquitos treatment plant is to
be located. One line runs north of Batiquitos Lagoon, terminating at a
pumping station on the north side of the lagoon, immediately east of Inter-
state 5. Series IV-B population projections show flows of about 0.4 MGD
in this sewer by 1985. These flow projections include approximately k
VII-6
0.15 MGD from a proposed mobile home park, located west of Interstate 5
and immediately north of Batiquitos Lagoon. Flows from this proposed
project are included, even though it is anticipated that Coastal Commission
approval for that project may be difficult to obtain. Ultimate flows are
expected to reach 1.0 MGD. These flows are based on the expectation that
the La Costa North area east of El Camino Real and south of Palomar Air-
port Road will be sewered to the trunk line located in Palomar Airport
Road rather than to the Batiquitos facility.
The other trunk line extends along the coast highway. This line
carries flow from the Leucadia County Water District and the Encinitas
Sanitary District. The 1985 and ultimate waste water flow through this
sewer is projected to be 4.0 MGD and 4.6 MGD respectively. However, it
should be pointed out that, since both agencies plan to develop reclaimed
water programs,it is likely that flows in the trunk line will be less than
the projected totals. These flows are not included in the planning for
the Batiquitos reclamation plant. However, the gravity sewer and the pro-
posed Leucadia fail-safe connection may be incorporated into the
Batiquitos planning.
Reuse Market
The initial potential market for reclaimed water consists of approxi-
mately 614 acres of agricultural land that are considered to be within
economic distance of the reclamation plant general location. The locations
are shown on Figure VII-1. Based on use of previously established criteria,
this market will require an annual average flow of 420 acre feet.
There are plans for the development of a 300 dwelling unit residential
development on property owned by Covington Brothers immediately north of
Batiquitos Lagoon. This subdivision has received City and Coastal Com-
mission approval and therefore is ready to proceed with construction as
soon as sewerage capacity is available. The reuse requirements of this
development are considered part of the initial market for the Batiquitos
facility.
VII-7
The County park proposed along the north shore of the lagoon is expected
to have a total size of approximately 1,080 acres. Based on preliminary
planning, it appears that very small amount would be in irrigation land-
scaping.
There are no existing or potential industrial reuse locations in this
area.
Storage Facilities
There are several potential storage facility sites within the service
area of the contemplated Batiquitos reclamation plant. These sites are
located on natural drainage courses where diversion facilities must be
constructed to avoid impoundment of natural runoff. Acquisition at sites
and construction of these storage facilities should be keyed to the growth
of the reclamation plant. The exact order of construction of the storage
facilities is not of critical importance since any one of the sites can be
adapted for use within the reuse system at any given point in time.
Capacity of the storage reservoirs would be determined at the time of
design. Obviously, the largest economically sized reservoir would be con-
structed so as to maximize the amount of reclaimed water that can be used.
Excess Effluent Lines
An excess effluent outlet from the Batiquitos site can be constructed
to the Encina treatment facility with little difficulty. The regional plant
and outfall is located only 10,000 feet from the existing waste water pump-
•mg station site. The easement for the existing gravity sewer lines serving
the area can be utilized for this outlet thus simplifying the land acquisi-
tion problem. The same pipeline will be used for the distribution of re-
claimed water to the agricultural reuse areas.
VII-8
Development Program
The initial step recommended to develop the Batiquitos system is to
construct a secondary level sewage treatment plant with up to 0.4 MGD capa-
city. This treatment plant is sized to treat the sewage flows expected
from the north Batiquitos trunk sewer in 1985. Concurrently a 12-inch •
pressure effluent line would be constructed from the treatment plant to the
Encina ocean outfall. Those agricultural lands shown on Figure VII-1 would
tap off of the effluent line to irrigate on an "as needed" basis. A local
storage reservoir, capable of holding approximately 30 days' storage would
be provided to supply peak days during July. It is assumed that the irriga-
ted area would be located west of Freeway 1-5, where demoralization to
meet water quality objectives is not required.
Using this configuration, approximately 64 acres of agricultural lands
could be irrigated with reclaimed water. Approximately 35% of the reclaimed
water would be utilized for irrigation. The remaining 65% would be dis-
charged to the ocean, primarily during winter months.
An alternative development program is to provide 90 day storage capa-
city instead of an effluent disposal line. This would enable the plant to
store all of the effluent treated and thereby serve an additional irrigation
market. Under this configuration, approximately 180 acres of land would be
irrigated with no discharge to the ocean. Eventually, when an effluent line
is connected to the ocean and other satellite plants are brought on line,
the 150 million gallon capacity reservoir would be converted to a peaking
reservoir capable of storing approximately 20 days' -flow.
As will be seen in the following chapter, the reclamation master plan
indicates an effluent disposal line although a holding reservoir could be
constructed initially as an alternative. It makes little practical differ-
ence which facility is constructed first. The pipeline would be slightly
less expensive to construct. However, timing problems in obtaining ease-
ments might tend to make a private developer opt for the storage reservoir.
The final decision might depend on the source of funding.
VII-9
During the intermediate phase of the development of the system, the
Batiquitos reclamation plant would be expanded to provide service for new
residential developments within its service area. Present indications are
that .agricultural lands within the coastal zone will be preserved through
this phase. Urban land, with its accompanying market for landscape irriga-
tion, will be located to the east of the reclamation plant site. Storage
facilities constructed in the initial phase will hold only a portion of the
increased reclaimed water production capacity. This would mean an increased
percentage of discharge to the ocean until larger storage reservoirs are
constructed in the final stages of the recommended reclamation master plan.
The estimated cost for constructing each of the components of this
system is shown on Table VII-3. The table represents total estimated cost
of construction. The figures presented do not consider the source of funds.
Since initial funding by private developers is anticipated, there should be
little or no cost to the City of Carlsbad for the first phase of the pro-
ject.
TABLE VII-3
SUMMARY OF ESTIMATED CONSTRUCTION COSTS
BATIQUITOS SYSTEM
COMPONENT
0 . 4 MGD Capacity
Secondary Treatment Plant
0.4 MGD Capacity
Filtration and Extended
Chlorination
12 Million Gallon Capacity (30 Da)
Storage Reservoir and
Associated Piping
12,000 - 12" Pressure Pipe
and Effluent Pump Station
TOTAL
COST
31,200,000
S 300,000
S 600,000
S 360,000
S 2,460,000
Note: Cost includes: engineering and construction
supervision 3 10%, and contingencies I 10%.
SNR Index =3300
PALOMAR AIRPORT RECLAMATION FACILITY
Location
The location of the various features comprising the Palomar Airport
reclamation facility are shown in Figure VII-2. They will be discussed in
the following sections. There is a confluence of major sewer lines immedi-
ately south of Palomar Airport which make this location ideally suited for
a major reclamation facility. The service area contains a good deal of
industrial development which offers a possible market for reuse, and at
the same time makes the contemplated site more acceptable for a reclama-
tion plant.
Suggested Plant Sites
As stated, the industrial nature of the area is compatible with siting
of a waste water reclamation plant. Four suggested sites have been studied.
However, in this instance it should be emphasized that a number of other
sites might be made available depending upon specific land use decisions and
the layout of the new industrial areas. All are located within a 1,000
meter radius circle.
One site would be at the west end of the proposed Japatul development
north of the airport. This location would require pumping of raw waste
water from the existing sewer lines to the plant site. The biggest advant-
age of this site is that it could probably be acquired as part of the Japa-
tul development, thus minimizing land acquisition difficulties. Reclaimed
water from this site would have to be pumped to the areas of the agricultural
reuse.
Another location considered is the area to the west of the existing
Carlsbad Industrial Park south of Palomar Airport. This location has the
advantage of being directly over all of the existing sewer lines thus
minimizing the pumping of raw waste water for reclamation purposes. A
disadvantage of this location is its relatively low elevation which would
require Dump in all areas of reuse.
vii-n
ITE SELECTION LIMITSPALOMAR AIRPORT
RECLAMATION PLANT
TREATMENT
E O E N D
AGRICULTURALMARKETS
MAJOR TRANSMISSION
LINES
(NEW STORAGE
RESERVOIR
PA L. OM AP Al P IP GST
PHASE 1 (1B8B)
A third site investigated is on County-owned land in the southwest
quadrant of the El Camino Real-Palomar Airport intersection. This location
also on the existing sewer lines, thus minimizing pumping of raw waste
water. It is also at a higher elevation, which would make it possible to
serve much of the agricultural reuse area by gravity.
Waste Water Quality and Reclaimed Water Quality
The waste water quality at the Palomar Airport site can be estimated,
based on data accumulated by the San Marcos District and the Buena Sanita-
tion District as shown in Table VII-4, along with the anticipated quality
of reclaimed water following secondary treatment and demineralization. Re-
quirements for ground water objectives in this area are also listed in
Table VII-4. The reclaimed water produced by the proposed plant would meet
the irrigation requirements for the area.
Potential Waste Water Flows
Existing and projected waste water flows to the Palomar Airport site
are shown on Table VII-5.
Construction of new residential and industrial developments in the
immediate area of Palomar Airport will supplement the flows from upstream
agencies in the coming years. It is not anticipated, however, that there
will be any significant increase in flows from those upstream agencies.
This is based on the assumption that new flow from these areas will, for
the most part, be utilized for landscape irrigation of upstream areas and
and thus would not be come available for reuse in Carlsbad. If this trend
should not occur, the additional flows would be available in Carlsbad.
VII-13
TABLE VI1-4
PALOMAR
ANTICIPATED RECLAIMED
WATER QUALITY
1
3
CONSTITUENT
Biochemical Oxygen
Demand
Suspended Solids
Total Dissolved
Solids (4)
Total Phosphorus
Total Nitrogen
WASTE BASIC
WATER RECLAIMED
(mg/1) WATER
(mg/1)
250 30
250 30
aOO(3) 800
10 10
TREATED' 'RECLAIMED
WATER
(mg/1)
5
0
400
1
30 20 5
(1) Secondary Treatment And Disinfection
(2) Advanced Treatment Including Demineralization
(3) Assumes Blended Water Supply
(4) Ground Water Obiective 1200 ms/l in area
TABLE VII-5
EXISTING AND PROJECTED WASTE WATER FLOWS
PALOMAR AIRPORT SITE
FLOW SOURCE
San Marcos County
Water District
Suena Sanitation
District
La Costa North
(Carlsbad)
TOTAL
NOTE: Flows based on
plants will be
PRESENT FLOWS
(WGO)
2.46
.54
0
3.10
Series IV-B projections
constructed.
1985 FLOWS ULTIMATE FLOWS
(MGD) (HGD)
3.78
1.45
.53
5.76
and the assumption
9.16
4.18
3.0
16.34
that no upstream
«f
k y
VII-14
Reuse Market
There is a substantial agricultural area existing to the west, south,
and east of Palomar Airport Road. The existing reuse demand in this area
is estimated to be as high as 2,450 acre feet a year. The areas are shown
on Figure VII-2.
There are existing and proposed industrial developments immediately
south of Palomar Airport and the proposed Japatul Industrial Park to the
north of Palomar Airport. Current estimated reclaimed water demand is
minimal. The estimated potential demand of these industrial areas is
difficult to project. However, the availability of reclaimed water could
attract more water consuming industries. Should such a demand develop,
reclaimed water could be readily supplied with the facilities proposed.
Cooling water is visualized as the major reuse activity. Single-pass
cooling would not constitute a consumptive reuse, since most of the water
would be returned to the disposal system.
In summary, it appears that the reuse requirements for the Palomar
Airport reclamation facility would for some time be dependent upon agricul-
tural activities. The quantity of industrial reuse would not be significant
nor would new developments in the immediate area create a substantial urban
market.
Storage Facilities
A number of sites could serve for small volume storage for the
Palomar Airport facility. A larger reservoir site is located southeast
of Palomar Airport and El Camino Real Roads, and is shown on Figure VII-2.
As with the Batiquitos plant, the planned plant capacity would be maximized
which, in turn, would minimize reservoir requirements.
VII-15
Excess Effluent Line
The size of the proposed Palomar Airport reclamation facility would
make it necessary to construct an 18-inch pressure effluent outlet to the
Encina ocean outfall. Ultimate planning includes two lines to the ocean
outfall. Such a configuration would serve the maximum irrigation market.
Development Program
The Palomar Airport reclamation system could develop in a number of
ways. Ultimately, a plant is required with a treatment capacity of 5.0 MGD.
This could be built in stages if desired. In light of its ultimate capacity,
the Palomar Airport plant would be the major source of reclaimed water for
the completed reuse system network.
The logical first step would be to construct a 2.6 MGD plant. This
plant would utilize waste water originating in Carlsbad and flows from
Buena and San Marcos for reclamation purposes. An 18-inch diamater ef-
fluent disposal line would also be constructed along the south side of
Palomar Airport Road, roughly in the location shown on Figure VII-2. During
the intermediate phase of the program, the plant would be expanded to a
capacity of 5.0 MGD. During the same time period, a second distribution
pipeline would be constructed from Palomar Airport Road, passing through
the area north of that road. This will permit irrigation of developing
urban areas, as well as the agricultural areas along the coast which
are expected to be retained.
Alternatively, a 1 MGD plant could be constructed with a 100 million
gallon storage reservoir, but no excess effluent connection would be
provided. The reservoir would serve as a peak demand storage facility
after the reclamation plant is built to its ultimate capacity and an
excess effluent connection is installed.
VII-16
'Finally, in the ultimate stages of the program, a major new storage
reservoir would be constructed at a central point in the system. The
estimated cost of the completed system is shown on Table VII-6.
TABLE VII-6
SUMMARY OF COSTS
PALOMAR AIRPORT SYSTEM
COMPONENT
2.5 MGD Capacity
Secondary Treatment Plant
2.5 MGD Capacity
Filtration and Chlorination
Demineralization
75 Million Gallon Capacity (30 Da)
Storage Reservoir and
Associated Piping
20,000'-18"—Pressure— . - ••-
Pipe and Pump Station
TOTAL
COST
S 6,000,000
$ 1,500,000
S 2,500,000
$ 1,000,000
S 600,000
$11,600,000
Note: Price includes: engineering and construction
supervison 9 10% and contingencies 8 10%.
EUR Index » 3300
k
VII-17
ENCINA RECLAMATION FACILITIES
Location
The Encina facility can be incorporated into the satellite concept
as a source of relatively small quantities of reclaimed water. A small
reclamation plant would be sited at the present Encina Water Pollution
Control Facility and would take advantage of some of its processing units.
Since the volumetric requirements of the waste water reclamation program
are substantially lower than the total combined agencies' sewage flow,
only a fraction of the waste water arriving at the regional plant would be
reclaimed at any time during the coming years.
Upon completion of the Encina Phase III expansion presently under
design, the plant would be providing secondary treatment for up to 18 MGD
by the year 1985.
Reclamation Plant Site
In the case of the reclamation facility at Encina, the only site con-
sidered is that of the present Encina Water Pollution Control Facility.
Master planning of the Encina site contemplates use of all of the land for
the ultimate 45 MGD plant. It will, therefore, be necessary to obtain
additional land in order to provide advanced treatment facilities required
to meet water quality standards for reclaimed water. Because of its
location on the coast, no storage facilities or excess effluent line will
be required at the Encina reclamation plant.
Waste Water Quality and Reclaimed Water Quality
Waste water quality at Encina is well documented by analytical data
submitted to the Regional Water Quality Control Board as part of the Encina
monitoring program. Based on test results, it is concluded that the
VII-18
quality of waste water at Encina is relatively poor for reuse purposes.
Salt content is currently 1200 mg/1 expressed as IDS. Demineralization of
this waste water will be necessary before it can be reused. This is both
an expensive and energy intensive process. The Encina plant is downstream
from all industrial discharges to the sanitary sewer. Hence, the waste
water may contain trace metals or other toxic materials incompatible with
the planned reuse. A strictly enforced source control program would be
required to prevent crop damage from toxic materials in the waste water flow.
Reuse Markets and Development Program
Agricultural markets do exist for reclaimed water in the immediate
vicinity of the Encina plant. However, they can be adequately served by
contemplated pressure effluent disposal lines for other plants which con-
verge at the Encina site.
The present plant expansion will require several years to complete.
Until the necessary secondary treatment facilities are constructed, Encina
cannot begin to produce reclaimed water. Since the construction of Encina
Phase III expansion is expected to be completed by mid-1982, Encina should
not be expected to play a major role in the reclaimed water program until
after the immediate development period previously described.
Encina's role in the overall reclamation program will not occur until
the intermediate phase of the recommended reclamation master plan. The pro
vision of secondary treatment facilities at Encina is part of the Phase III
expansion there. Present scheduling of construction and allowance for a
start-up period will mean that secondary effluent will not be available
until early 1985. Reclamation and reuse of a portion of the Encina plant
is anticipated for 1985.
Once the outlying satellite treatment plants are constructed and the
reclaimed water demand is established on a demand basis,plans can be formu-
lated to bring Encina into the system- The Encina facility is excellently
located to serve new industry with reclaimed water. The possibility should
VII-19
be kept in mind during any future discussion with industries considering
locating in Carlsbad; should the opportunity arise, reclaimed water of
lesser quality can be supplied from Encina at any time following completion
of Phase III.
As currently envisioned, the three outlying plants would produce suf-
ficient reclaimed water to meet first phase agricultural demand. However,
as urban demand grows, an estimated 0.8 MGD of additional treatment capacity
will be required by 2005. This addttional capacity can be developed at Encina.
Once advanced waste water treatment facilities are constructed, the plant
can be connected directly into the excess effluent lines constructed from
the outlying satellite plants. As demand increases, appropriately treated
flows from the Encina reclamation facility would be pumped back to the reuse
areas. The cost of a 1.0 MGD capacity advanced waste water treatment
facility at Encina, including filtration, extended chlorination and 1.0 MGD
desalting is estimated to be $1.5 million. A breakdown of this cost estimate
is shown in Table VI1-7. The desalting unit will be required to produce
a satisfactory quality of reclaimed water for irrigation purposes.
TABLE VI1-7
SUMMARY OF COSTS
ENCINA SYSTEM
COMPONENT
Secondary Treatment
Plant
1.0 MGD Capacity
Filtration and Extended
Chlorination
1.0 MGD Capacity
Oemineralization
TOTAL
COST
$ 0*
S 600,000
S 900,000
51,500.000
*Use Secondary Facilities at Sncina
ENR Index = 3300
]
VII-20
I
BUENA VISTA RECLAMATION FACILITY
Location
The City of Oceanside currently owns a 0.5 MGD capacity secondary
sewage treatment plant located on Buena Vista Lagoon near the El Camino
Real crossing. Although the plant is not currently in use, secondary
treated effluent could be readily produced.
The plant contains facilities for conventional activated sludge treat-
ment with anaerobic sludge digestion. Existing facilities would have to be
overhauled and rehabilitated. The use of anaerobic sludge digestion is
deemed inadvisable at this site because of potential odor problems. A de-
cision would have to be made at the time of rehabilitation concerning con-
struction of a new aerobic digestion unit at the site or directing the
waste solids to the regional system for processing.
Unfortunately, the market for reclaimed water in the area is quite
limited. In addition, the institutional arrangements necessary to lease
or acquire the plant from the City of Oceanside may be complicated.
Potential Waste Water Flow
City of Carlsbad waste water will be available in limited quantity
at the Buena Vista site. However, flows from the upstream Vista Sanitation
District or City of Oceanside systems could be diverted for use at this
location. Raw sewage flows through adjacent interceptors now exceed the
capacity of the Buena Vista plant and also exceed anticipated reuse needs.
The estimated quantities of sewage from the Vista Sanitation District and
the City of Carlsbad are shown in Table VII-8.
Rough estimates indicate that there could be as much as 75 acres of land
available for irrigation by 1985. An area of this size would utilize flow
from a plant with a capacity of 0,5 MGD during the peak summer irrigation
season. f.A
VII-21
TABLE VI1-8
WASTE WATER FLOWS AVAILABLE
BUENA VISTA
RECLAMATION FACILITY
YEAR FLOW
VISTA SANITATION
DISTRICT
(MGD)
1980
1985
1990
1995
2000
2005
3
4
4
6
7
9
.9
.1
.9
.0
.9
.1
FLOW
CARLSBAD
(MGD)
0
0
0
0
0
0
.1
.4
.5
.6
.7
.9
TOTAL
(MGD)
4
4
5
6
3
10
.0
.5
.4
.6
.6
.0
Storage Facilities
Since a relatively large quantity of waste water can be obtained for
reclamation purposes from Vista Sanitation District, it would not be neces-
sary to provide substantial storage volumes at this location. Therefore,
only relatively small equalizing storage reservoirs would be planned.
Effluent Connection
An excess effluent outlet can be provided for the Buena Vista plant
by the construction of a line paralleling El Camino Real, tying into the
proposed Lake Calavera effluent line. In lieu of this, the Buena Vista
plant could be of the "on-line" variety,.producing reclaimed water only
when needed. Otherwise, the raw sewage would continue on to Encina for
treatment and disposal. With this configuration, full treatment capacity
would have to be held in reserve at Encina.
]
i
VII-22
3
3
Development Program
Because of its location apart from the rest of the reclamation facili-
ties shown in the reclamation master plan, the Buena Vista facility could
be independently reactivated at almost any time. The exact timing would
depend upon the growth and development of a need for reclaimed water in the
immediate area.
Initially, the plant could be operated on an "on-line" basis, with
excess reclaimed water being discharged to the sanitary sewer. While this
arrangement would not provide additional sewer capacity, it would permit a
reclaimed water distribution system to be developed in the area. The exist-
ing 0.5 MGD plant would be able to meet the peak irrigation demands for
about 85 acres of landscape.
During the intermediate development phase of the program, the option
to integrate the Buena Vista plant into the overall satellite system would
be open. To joint Buena Vista to the network, a pressure reclaimed water
pipeline would be constructed parallel to Camino Real to join the proposed
Lake Calavera pipeline south of the Lake Calavera Hills development. Dual
water systems in new urban development along the connecting pipeline could
expand the reclaimed water market.
The final stage of development of the Buena Vista system would be to
retrofit the existing urban areas with reclaimed water Lines. In this way,
highway right-of-way and peak landscape irrigation could use reclaimed water.
An alternative approach to establishing a reclamation program for the
Buena Vista plant might be development of a larger project in cooperation
with the City of Oceanside. The additional waste water flow available at
the Oceanside Buena Vista pumping station could be combined with the flows
from Carlsbad. The reclamation system might serve reclaimed water to lands
in the City of Oceanside as well as in the City of Carlsbad. However, dis-
cussion of waste water reclamation opportunities in the City of Oceanside
is beyond the scope of this master plan study; a separate program would
have to be developed for the City of Oceanside and coordinated with that
of the City of Carlsbad. «
VII-23
LAKE CALAVERA RECLAMATION FACILITY
A 3,700 acre area near the Lake Calavera Hills development was the
subject of a previous study by James M. Montgomery,Consulting Engineers,
Inc. entitled Environmental Impact Report and Facilities Plan for a
Satellite Sewage Treatment Facility. The report proposed that a 1.2 MGD
satellite treatment plant be constructed at a site approximately one mile
southwest of Lake Calavera. The location of the plant is shown on Figure
VII-3.
As currently proposed, the project consists of a 1.2 MGD oxidation
ditch satellite waste water treatement plant on a four acre parcel. First
phase construction would be for a flow of 0.5 MGD. Effluent would be
percolated into the ground and then pumped out for reclamation through
agricultural irrigation. Sludge would be thickened, dewatered, and hauled
to the nearest Class II landfill. Effluent flows in excess of irrigation
needs would be percolated for later use or shunted down an excess effluent
line to the outfall of the Encina water pollution control facilities. The
proposed facilities are shown in Figure VII-3.
The Lake Calavera Hills reclamation program has received the approval
of the City Council. For purposes of this study, it is assumed that the
Lake Calavera Hills plant will be constructed as presently planned. It is
therefore included in the recommended reclamation master plan. An excess
effluent outlet from this facility to the Encina plant is visualized as a
later development of the reclaimed water distribution system.
Present planning for the Lake Calavera Hills reclamation plant antici-
pates that subsurface storage of treated effluent will be utilized in the
first phases. The major subsurface aquifer at the head waters of Agua
Hedionda Lagoon will be utilized for storage purposes during the intermediate
and final phases of the program development. Ultimately, an excess effluent
line would be constructed to the pipelines serving the Palomar Airport
Facility. During this same time period, the Lake Calavera Hills capacity
would be increased to 1.2 MGD in order to reclaim water produced by
additional residential developments anticipated in the area.
VII-24
•k
j
I
r\3en
CALAVERA TREATMENT PLANT
LEGEND
TREATMENT
AGRICULTURAL
MARKETS
GROUNDWATER STORAGE
MAJOR TRANSMISSION
LINES
LAKE CALAVERA
HILL* PHASE 1 (1MB)
AGUA HEDIONDA RECLAMATION FACILITY
The "Overview Report" called for a 0.3 MGD capacity satellite treat-
ment plant to be constructed at the eastern end of Agua Hedionda Lagoon.
It now appears that the Lake Calavera plant and Buena Vista plant are
capable of meeting all of the reclaimed water demand in the area. There-
fore, the construction of the Agua Hedionda plant is not considered as part
of the recommended program. If, in the future, an increased irrigation
demand devlops and a major trunk line is constructed down Agua Hedionda
Creek, constructing the Agua Hedionda facility may become feasible.
VII-26
CHAPTER VII!
INTEGRATION OF
INDIVIDUAL SATELLITE
WASTE WATER
RECLAMATION PROJECTS
k
CONCEPT OF MASTER PLAN
The information contained in this chapter will be utilized to de-
velop a recommended reclamation master plan for the study area. As has
been explained, it will be possible to produce reclaimed water suitable
for general irrigation purposes with conventional secondary treatment of
the waste water. Advanced waste treatment facilities will be required
in order to meet the health requirements embodied in the Title 22 regula-
tions. In addition, advanced waste treatment in the form of demineraliza-
tion will be necessary in some locations to comply with the TDS limitations
imposed by the Regional Board.
The siting of reclamation plants will require particular care.
Satellite plants will be located in relatively close proximity to built-
up areas. Sites must, therefore, be compatible with the surrounding land
use. This will require landscaping and architectural treatment.
The individual reclamation plants described in the proceeding chapter
will be operated as independent units during the initial phase of the
implementation of the recommended reclamation master plan. Then starting
in the mid-1980's the plan will enter its intermediate phase. During this
time period there will be a gradual integration of the previously inde-
pendent facilities. The excess effluent lines originally constructed to
provide an outlet to the ocean will be connected into a single distribution
system so that reclaimed water from any plant can theoretically be utilized
anywhere in the study area. Major storage facilities operating on a sys-
temwide basis will be added during this phase. The completed system will
constitute the ultimate phase of the recommended reclamation master plan.
PHASED DEVELOPMENT OF AN INTEGRATED SYSTEM
At the present time there appear to be a number of private developers
willing to undertake the construction of reclamation plants and to provide a
substantial portion of the necessary market through the irrigation of land-
scaping areas within their developments. This landscape irrigation market.
coupled with the agricultural market already existing in Carlsbad, should
justify construction of the initial phases of several independent waste wate
water reclamation systems.
It is anticipated that the initial components will be constructed
for the most part by private interests, primarily to provide waste water
treatment capacity. Reclaimed water should be sold under contract to
support financing of system operation and maintenance. It appears that a
number of the individual satellite facilities discussed in the previous
chapter will be installed by the mid-1980's. During that same period, agri-
cultural demand for reclaimed water should grow substantially, as irrigators
shift from potable water supplies. This will occur if reclaimed water is
delivered with consistently good quality at a price lower than imported
water. Figure VIII-1 shows the first phase of the recommended reclamation
master plan.
The specific facilities recommended for the initial phase are as fol-
lows:
1. Batiquitos System
A reclamation plant with a capacity of 0.2 MGD and an excess
effluent connection to the ocean. To maximize reuse of the
reclaimed water, a 30 day storage reservoir would also be
provided. Volume would be 6.0 million gallons.
2. Palomar Airport System
A reclamation plant with a capacity of 2.5 MGD and an excess
effluent connection running through the reuse area south of
Palomar Airport Road. A local storage facility with a mini-
mum of a 10 day capacity would also be provided. The mini-
mum volume would be 25.0 million gallons. A larger reservoir
would be desirable if an economical site could be found.
3. Lake Calavera Hills System
In accordance with present planning by the City, the initial
phase construction at Lake Calavera Hills would consist of
a capacity of 1.2 MGD and a subsurface disposal and storage
volume suitable for a flow of 0.5 MGD. The capacity of this
facility would be limited to 0.5 MGD until additional dis-
posal capabilities are provided.
k
VIII-2
i
U)
LAKE CALAVERA HILLS
RECLAMATION PLANT
2000 0
SCALE IN FEET
SITE SELECTION LIMITSPALOMAR AIRPORTPLANT
LAKE CALAVERA HILLS
STUDY AREA BOUNDARY
ENCINA TREATMENT PLANTk fr)
\\ ^V^*^ v^B
o
LEGEND
TO IRRIGATION DEMAND
AGRICULTURAL LANDS
Sj^:a GROUNDWATER STORAGE
Illlll MAJOR TRANSMISSION LINES
MASTER PLAN INITIAL
PHASE-1985
SITE SELECTION LIMITS BATIQUITOS
RECLAMATION PLANT
The intermediate phase of the recommended plan would add the follow-
ing facilities.
1. Batiquitos System
Enlarge reclamation plant to a capacity of 0.4 MGD.
2. Palomar Airport System
Enlarge reclamation plant to a capacity of 5.0 MGD. Add
major storage reservoir on exiting excess effluent line.
Add parallel excess effluent line passing through area north
of Palomar Airport Road.
3. Lake Calavera Hills System
Provide additional subsurface disposal area to increase
usable capacity of system to 1.2 MGD.
4. Encina Satellite System
Construct a reclamation plant with a capacity of 0.9 MGD.
This plant would use secondary effluent from the
regional treatment plant.
The ultimate phase of the plan would add the following:
1. Lake Calavera Hills System
An excess effluent line connecting this facility to the rest
of the system would be provided.
2. Encina Satellite System
Enlarge reclamation plant up to a limit of 18.0 MGD to accoma-
date any specific industrial reuse that develops during this
time period.
3. Buena Vista System
Reactivate existing City of Oceanside treatment plant for
local reuse purposes. Capacity of plant to be 0.5 MGD. This
would require an agreement with Oceanside or outright purchase
of the facilities. Construct an excess effluent line con-
nected to the other pipe lines in the distribution system.
k
VIII-4
Increasingly, irrigation of public and quasi-public landscape should
create a demand for reclaimed water. As new customers for the reclaimed
water appear, the increased demand should result in extension of indivi-
dual distribution systems and their conversion to an areawide reclaimed
water network. Figure VI11-2 shows how the facilities constructed for each
individual satellite plant would be formed into a ragionwide system, serving
primarily agricultural markets during this intermediate phase. By the time
the program reaches the stage of development shown on Figure VIII-3, most
of the reuse would be on a demand basis. Individual users of reclaimed
water would have it available in a distribution system at the times and in
the quantities that they desire, rather than on a predetermined contractual
basis.
As the Carlsbad area becomes increasingly urbanized, urban landscape
markets are expected to consume an even greater percentage of the reclaimed
water produced. Most likely, distribution would be by means of a dual water
system. The majority of the non-potable water would be primarily utilized
for landscape irrigation purposes. Demand is expected to reach 4800 acre
feet per year. Advanced treatment facilities would be added at Encina and
the plant would be integrated into the reclaimed water network.
DISTRIBUTION SYSTEM
The piping system which is required to distribute reclaimed water from
the individual satellite reclamation plants to their respective use areas
constitutes the backbone distribution system serving all of the potential
market areas. Smaller delivery lines to individual users would be con-
structed from the basic pipe network at the expense of those individual
users.
Operating pressure of the reclaimed water distribution system would
be substantially lower than that of the potable system, as a means of pro-
tecting the potable supply from contamination and also to eliminate the
need for high pressure pumping of reclaimed water throughout the area. This
k
VIII-5
LAKE CALAVERA
RECLAMATION
SCAll IN FEET
LAKE CALAVERA HILLS
STUDY AREA BOUNDARY
SITE SELECTION
PALOMAR
RECLAMAT
ENCINA TREATMENT PLANT
TO IRRIGATION DEMAND
AGRICULTURAL LAND/
OPEN SPACE
URBAN LAND
GROUNDWATER STORAGE
Illlll MAJOR TRANSMISSION LINE
MASTER PLAN INT RMEDIATl
PHASE -1995 SITE SELECTION LIMITS BATIQUITOS
RECLAMATION PLANT
INTERCONNECTION WITH
OCEANSIDE RECLAMATI
STSTEM Calov*ra •
LAKE CALAVERA HILLS
RECLAMATION PLANT
1000 0 4000
SCALE IN FEET
BUENA VISTA '
TREATMENT PLANT
LAKE CALAVERA HILLSSTUDY AREA BOUNDARY
SITE SELECTION LIMITSPALOMAR AIRPORT
LAMATION PLANT
ENCINA TREATMENT PLANT)
LEGEND °
TO IRRIGATION DEMAND
TO IRRIGATION DEMANDREQUIRING RETROFIT OFEXISTING URBAN LANDS
OPEN SPACE
URBAN LANDS
GROUNDWATER STORAGE
RESERVOIR
Si I MAJOR TRANSMISSION LINES
SITE SELECTION LIMITS BATIQUITOS
RECLAMATION PLANTMASTER PLAN ULTIMATE
PHASE-2005
approach to the operation of the reclaimed water system would make it
necessary for the individual users to provide their own pumping systems
in order to boost the water to whatever pressure they require. Since the
pressure requirements would vary considerably with the type of reuse being
practiced, each user can utilize pumps to provide whatever pressure he
requires. At the same time, the operator of the overall system would not
be required to provide unneeded pressure throughout the pipe network.
The exact size and location of the distribution pipe lines would not
determined during detailed planning and design of those facilities. At
this time it can be estimated that the two lines from the Palomar Airport
area to Encina would be 18 inches in diameter. The line serving the
Batiquitos area would be 8 inches to 10 inches in diameter and the ultimate
connection from Lake Calavera Hills would be on .the order of 12 inches to
18 inches in diameter.
VIII-8
CHAPTER IX
ADDITIONAL PLANNING
CONSIDERATIONS
REGIONAL SOLIDS HANDLING
The feasibility of using the Encina plant as a central location for
handling all sludge solids from satellite plants throughout the area
served by that plant is now being seriously considered. From the point
of view of those operating the various reclamation plants, there would
be a number of advantages to such an arrangement. Since each of the
reclamation plants would be located in an area accessible to the waste
water sewerage system, it would be possible to discharge waste activated
sludge from the treatment processes into the sewer lines for processing
at Encina. Solids handling is the most critical and sophisticated of
all of the waste water treatment functions. Concentrating flows at one
location will enable solids to be handled by personnel specially trained
in this specific area.
Table IX-1 shows the effect of discharging to Encina the sludge from
satellite treatment plants with a combined capacity of 6.6 MGD. The
existing primary sedimentation tanks at Encina can accommodate the addi-
tional solids loading with a 2% reduction in primary treatment capacity.
Additional digester capacity would have to be provided at Encina, as
would additional filter belt press capacity at Encina.
Preliminary studies have been made by consulting engineers for the
Encina Joint Advisory Committee (JAC) which confirm that the extra solids
load could be handled at Encina without difficulty, providing the extra
digestion and dewatering facilities are provided. These studies have
emphasized that the discharge of such solids to Encina should not in any
way relieve the agencies operating the satellite plants from any obliga-
tion to contribute financially to the ultimate handling and disposal of
those solids. It would be reasonable to develop a separate set of cost
criteria for handling solids at Encina. The cost of resolving any
special problems arising from this function could be allocated back to the
operators of the satellite plants who have been relieved of the obligation
by discharge to Encina.
k
TABLE IX-1
ESTIMATED EFFECT OF SOLIDS HANDLING AT ENCINA
Sludge Volume from Satellite Treatment
Plants to be Added to the Primary
Clairifiers at the Encina Treatment Plant - 160,000 Gallons/day
Percentage of Total Flow - 1*
Additional Primary Sedimentation
Capacity Required
Necessary Additional Primary
Sludge Digester Capacity Required
NONE
- 140,000 Cubic Feet
Additional Digester Facilities Necessary - 80 feet by 20 feet
Deep Digester
Additional Primary Digested Sludge
Produced (Dry Solids)- 9,000 Ibs/day
Additional Filter Belt Presses Required - 2 Presses 8
2 Meters Each
Even if centralized solids handling facilities were provided at Encina,
it is recoimiended that sludge treatment and disposal capabilities also
be provided at the satellite plants envisioned in the recommended reclama-
tion master plan. These facilities would then serve as a backup system
in case of any unforeseen difficulties at Encina. They would also permit
the construction of the plants for first phase operation without having
to wait for solids handling capabilities to be developed at Encina.
If a regional solids handling program were established at Encina,
and if, in addition, the satellite plants on the system were to provide
backup solids handling capability, there would be an opportunity for inte-
grated operation of the satellite plants and the regional facility. As
an example, if there were an excess of solids at one point in the overall
system, satellite plants elsewhere could treat a comparable amount of
solids on-site, thus relieving the load at Encina.
k
IX-2
CONTACTS WITH IRR1GATORS
As has been previously discussed, the ultimate reclamation and reuse
system would provide reclaimed water on a demand basis for all customers.
This condition would be achieved only after several years of operation when
the entire storage and distribution system is in place and operational.
In the interim, it would be necessary to ensure a contractual market for
reclaimed water. This can best be done by establishing specific contracts
with irrigators, both agricultural and landscaping, to assure that they
will accept and use fixed amounts of the reclaimed water. Such arrange-
ments will be required by the Regional Board if no fail-safe connection is
provided. Even with a connection to the ocean, it would be desirable to
ensure as large a sale as possible in order to establish a fixed price
for the reclaimed water.
Since the developers of new residential areas are interested not only
in use of the reclaimed water but also in providing additional waste water
treatment facilities, arrangements for residential landscaping irrigation
with reclaimed water should be easy to arrange in the future. Contracts may
be established with homeowners' associations or special service areas of
the City of Carlsbad. Landscape irrigation utilizes more flow in the winter-
time and is better able to absorb fixed amounts of water by over-irrigation
if necessary. It is possible that reclamation facilities can be constructed
with guaranteed sales to landscape irrigators and demand sales to agricul-
tura users. It would be expected that if a particular reclamation plant
could be established on this basis, agricultural use would increase over
the early years. For this reason, it is recommended that initially, con-
tracts with landscape irrigators be considered the primary means of guaran-
teeing sale of reclaimed water.
As indicated above, one method of facilitating use of reclaimed water
for landscape irrigation would be the creation of landscaping districts,
service areas, or improvement districts which could contract for the re-
claimed water and pay through special assessments or service charges. Such
areas would probably tend to be formed coterminous with new developments,
thus permitting developers to take the responsibility for initiation of the
systems and to construct the required irrigation piping.
IX-3
PRICING CONSIDERATIONS FOR RECLAIMED WATER
The reclamation program will be performing two functions, treating
waste water and producing reclaimed water. Revenue will be produced from
both services. For treating domestic waste water, monthly service charges
will be collected. Similarly, a water charge may be collected from the
sale of reclaimed water.
As presently envisioned, the capital facilities for the satellite
system will be funded either by developer contribution or by grant funds.
State and Federal Clean Water Grant funds could, if the projects were eligible
for an extra 10% federal grant for innovative projects, amount to 97.5% of
eligible project cost, with the City of Carlsbad paying the remaining 2.5%.
Without the bonus, the grants would still amount to 87.5% of eligible
project costs, with the City paying the balance. Consequently, the City
should acquire the capital facilities without imposing major expenditures
on Carlsbad residents. The other remaining cost of the reclamation pro-
gram is the annual operation and maintenance (O&M) cost.
The O&M cost can be met by revenues collected for treating waste water
and selling reclaimed water. Logically, the sewer fees should cover the
O&M costs of secondary treatment of the waste water and transporting the
effluent to the ocean outfall. The O&M cost of providing waste water
treatment and reclaimed water storage should be met by the sale of re-
claimed water. Without knowing the exact plant layout or the final config-
utation of the reclamation system, it is difficult to separate the share
of the O&M costs attributable to each function. As a rough estimate,
Table IX-2 shows the approximate O&M costs of secondary treatment plus
conveyance and advanced waste treatment and storage for three satellite
waste water reclamation plants.
ft
IX-4
TABLE IX-2
ESTIMATED OPERATION & MAINTENANCE COSTS (1)
SATELLITE
PLANT
Calavera
(1.2 MGD)
Batiquitos
(1.4 MGD)
Palomar
(5.0 MGD)
COMPONENT
SECONDARY
TREATMENT
$115,000
$105,000
$347,000
$567,000
PIPES
!. PUMPS
$ 43,000
$ 20,000
$ 57,000
$120,000
A.W.T. (2) (3) STORAGE
S 36,000 $ 46,000
S 22,000 $ 17,000
$128,000 S 90,000
$186,000 $ 63,000
TOTAL
$ 240,000
$ 164,000
$ 622,000
$1,026,000
(1) For Interim Phase - 1985
(2) Advance
C3)' Power C
r.'ater Treatment
osts Based on 76
is extended CSlorination and Filtration
Per Xillowatt Hour
Only
As discussed earlier, at the intermediate point of the reclamation
program, in 1995, the three satellite plants will produce 6.6 MGD of
reclaimed water per day. The system is capable of producing about 7,400
acre-feet per year of reclaimed water. However, because of the annual
variation in agricultural water demand, about 2,650 acre-feet per year
will actually be sold for reuse. The remaining effluent will be discharged
to the ocean outfall. The O&M cost for advanced waste treatment and stor-
age was shown to be $249,000 per year. For the sales of the 2,650 acre-
feet per year of reclaimed water to pay for the O&M cost, the water must
sell for $93 per acre-foot. This is the price estimated at this time for
reclaimed water produced by the recommended master plan facilities. It
compares favorably with the $140 per acre foot price charged by Carlsbad
Municipal Water District.
The cost figure given above does not include O&M for demineralization,
which is estimated by the manufacturer of the equipment to be approximately
$200 per acre foot. Such an increment to the cost of reclaimed water
obviously will have a profound effect on the reuse market. The recommended
revision of ground water objectives can thus be seen to be a critical item
in the reclamation and reuse program.
IX-5
MODIFICATION OF WATER QUALITY OBJECTIVES
The foregoing discussion illustrates why the City of Carlsbad should
seek revision of the groundwater quality objectives of the Basin Plan at
the outset of its waste water reclamation planning. It has just been
pointed out that demineralization costs would add approximately $200 per
acre foot to the cost of reclaimed water, resulting in a profound adverse
effect on the viability of the reclamation program.
At several points earlier in this report, factors influencing the need
for demineralization have been explained. These factors are: (1) an exces-
sive level of salts contained in the sewage supply used to produce reclaimed
water, and (2) compliance with anticipated total dissolved solids limitations
of the Regional Water Quality Control Board. Demineralization required to
correct high sewage salinity can be avoided by locating the proposed reclama-
tion plants in areas where the salinity of raw sewage flows is within
acceptable limits. Demineralization required to meet the regulatory re-
quirements of the Regional Water Quality Control Board can be avoided only
if the groundwater quality objectives of the Basin Plan are modified.
Under the provisions of the Porter-Cologne Act, a regional water
quality control board may revise the water quality objectives of its Basin
Plan from time to time. Amendments usually take place when changes in
beneficial use of the waters of the state occur, or as more detailed infor-
mation concerning the type or level of beneficial use in a hydrologic sub-
unit becomes available.
The San Diego Regional Water Quality Control Board recently reviewed and
updated the water quality objectives of its Basin Plan. Revisions made have
been reviewed and approved by the State Water Resources Control Board and
EPA. In a number of areas throughout its region, the Board eliminated
numerical groundwater quality objectives, since it had been determined that
groundwater uses do not exist.
In the vicinity of the waste water reclamation plan study area, the
Regional Board eliminated groundwater quality objectives west of Freeway k
IX-6
1-5 in the Buena Vista, Agua Hedionda, Canyon De Las Encinas and San Marcos
Creek Basins. In addition, it eliminated groundwater quality objectives
in the San Marcos Creek Drainage Basin from State Highway 78 downstream to
El Camino Real. Thus, lands lying between El Camino Real and the freeway
continue to be subject to groundwater quality objectives. It is within these
lands that preponderance of waste water reclamation activities is visualized
to take place.
As already reported, a survey made as part of this study has shown that
groundwater uses do not exist in the reclaimed water use area contemplated
for the Batiquitos, Palomar Airport and Encinas reclamation plants. There
appears to be more than sufficient justification for requesting the Regional
Water Quality Control Board to eliminate numerical groundwater quality
objectives in an additional large area of Carlsbad. Generally, the area
would be described' as having its southerly boundary along the north shore
of Batiquitos Lagoon; its westerly boundary along Freeway 1-5, extending
from Batiquitos Lagoon to Agua Hedionda Lagoon; its northerly boundary along
the southerly shore of Agua Hedionda Lagoon to the inland extremity of the
lagoon, then along the divide between Agua Hedionda Drainage Basin and the
Canyon De Las Encina Drainage Basin to El Camino Real; its easterly boundary
along El Camino Real from the aforementioned divide south to San Marcos
Creek.
Elimination of groundwater quality objectives within the area just des-
cribed should make it possible to practice waste water reclamation without
demineralization, provided that the reclamation plants are located where
acceptable quality sewage can be obtained. As already pointed out, reduction
of demineralization to a minimum or its complete elimination can determine
the financial viability of a contemplated reclamation project.
Obviously, the City of Carlsbad should submit a request for revision of
groundwater quality objectives. The following steps would be involved:
(1) Assembling all information available on groundwater use or
lack of such use within the defined area into a brief report;
k
IX-7
(2) Submittal of the above report to the Regional Water Quality
Control Board, along with a request that the water quality
objectives for groundwaters be eliminated; and
(3) Testimony at a public hearing of the Regional Water Quality
Control Board. The Regional Board would probably schedule
this hearing upon receipt of the request from the City of
Carlsbad.
IX-8
CHAPTER X
RECOMMENDATIONS FOR
IMPLEMENTATION OF A SATELLITE
WASTE WATER PLAN BY THE
CITY OF CARLSBAD
ft
GENERAL CONCLUSION
The general conclusion reached in this study is that a waste water
reclamation and reuse program for the City of Carlsbad is desirable and
feasible and should be adopted and implemented by the City.
RECOMMENDATIONS
Reclaimed Water System Configuration
The type, location and phasing of waste water reclamation facilities
recommended as a result of this master plan study are presented on Plate
A in the rear pocket of this report. Plate A is intended to constitute a
formal presentation of the recommended reclamation master plan, subject
to revision before formal adoption by the Carlsbad City Council.
The recommended plan is based on the assumption that a number of
satellite plants will be constructed independently over the next few years.
During the first phase of construction, each plant would be operated as a
separate entity with provision for storage or reuse of the anticipated waste
water flows.
Briefly, establishment of the ultimate waste water reclamation system
is visualized as progressing in the following stages:
1. Initial phase will provide for independent systems at Bati-
quitos, Palomar Airport and Lake Calavera Hills. The first
two will be provided with excess effluent connections to the
ocean. Lake Calavera Hills will utilize subsurface disposal.
2. The intermediate phase of the master plan will include
enlargements of the three reclamation facilities, the con-
struction of a parallel excess effluent line from Palomar
Airport to the ocean, and the enlargement of the disposal
capability at Lake Calavera Hills. A major storage reservoir
would be provided on the Palomar Airport excess effluent line.
A small reclamation plant using secondary effluent from the
regional treatment plant could be constructed at Encina.
k
3. The ultimata phase of the master plan envisions the addition
of an excess effluent line from Lake Calavera Hills and
the reactivation of the Buena Vista treatment plant
presently owned by the City of Oceanside. An excess effluent
connection from Buena Vista to the rest of the distribution
system would be provided.
This program can be developed in its early stages with minimum
capital funds from the City by relying on grant funds and private de-
velopers. Once the system is established fees for reclaimed water usage
would be used to finance the expansion of the system in a manner similar
to that utilized for expansion of potable water systems.
PURVEYING AGENCY
No attempt has been made to analyze the institutional structure of
the waste water reclamation and reuse facilities. Reclamation and reuse
bridges the historic gap between waste water treatment and disposal
agencies and water purveying agencies. Both functions can be, and often
are, administered by a single entity. This has the advantage of providing
a complete water management capability administered under one responsi-
bility.
Sewering agencies are best suited to operate and maintain the recla-
mation facilities since they are, in essence, waste water treatment plants.
The storage and distribution of reuse water is an activity identical to
storage and distribution of potable water and, hence, would more naturally
fall within the area of expertise of water purveying agencies. The City
of Carlsbad presently carries out both of these activities and, hence is
well suited by existing legal power and experience to act as the opera-
tor of the integrated reclamation and reuse program.
k
X-2
SALE OF RECLAIMED WATER
The policy recommended is that reclaimed water be offered for sale
at no less than the true net cost to produce and distribute. If this
cost is greater than the cost of potable water, it is doubtful that there
will be agricultural customers. Landscape irrigation may still be a
viable market since developers would find themselves in the position of
having to subsidize the reclaimed water facilities in order to obtain
waste water treatment and disposal capacity.
Establishing the true cost of imported water, or reclaimed water,
is an exceedingly difficult matter. Imported water has been subsidized
over the years by a number of federal and state programs, going all the
way back to the mid-19301s. As previously discussed, sources of funds
for reclamation facilities are expected to be varied, with only a small
percentage coming from city general funds. In addition, the property
tax income from many of the water agencies acts as a subsidy to the
narket price of potable water.
Despite all these complications, the final decision to be made by
an irrigator will be dependent upon his or her actual cost. Increasing
costs of providing imported water, particularly with regard to anticipated
increases in the cost of energy, which will impact imported water to a
higher degree, will change the relative cost of the two sources of water
on an almost continuing basis. Projections of the cost of power and the
resultant cost of both imported and reclaimed water are shown in Figure
X-l and X-2. These curves indicate that over the years the cost of potable
water will increase to the point where reclaimed water will be competitive.
At that time a natural agricultural market will develop. In the interim,
if desired, the reclaimed water could be artificially subsidized, either by
a surcharge on the landscape irrigation uses or from City funds. No esti-
mates of the amount of this subsidy have been prepared for this study.
X-3
.15 -
.10 -
at
Ul
O.
in
H"ztuu
.05 -
.00 -I
1975 I960 1985 1990
YEAR
1995 2000
SDG&E PROJECTED POWER COST
FIGURE X-1
X-4
1500-1
1000-
intt
Oa
O
O
aeu
OS
Ul
°- 500
Ou
0-1
1980 1990 2000
NOTE:YEAR
A.W.T.& DISTRIBUTION- O&M ONLY
A. W.T.& DISTRIBUTION CAPITAL &O&M
TREATMENT & A.W.T.-O&M ONLY
TREATMENT&A.W.T.-CAPITAL&O&M
POTABLE WATER
2010
ESTIMATED UNIT COST OF WATER
FIGURE X-2
X-5
TIMING OF IMPLEMENTATION
The concept of waste water reclamation and reuse developed in this
report is based upon providing a maximum flexibility in construction
of the various parts of the system. However, three key years are
stressed. The first is 1985. By that time it is anticipated that indi-
vidual reclamation facilities, essentially independent of each other, will
be established. Each of these independent systems will provide necessary
storage facilities for excess effluent disposal capabilities and firm
marketing contracts for the disposal of the reclaimed water produced. The
second key date is 1995. This marks the mid-point of the conversion of
the reclamation and reuse system from a series of independent projects to
a single integrated system. The final point in time is the year 2005.
This is the date by which it is assumed that the individual reclamation
systems will have been connected into an integrated, reclaimed water
storage and distribution system, serving customers on a "demand" basis.
Beyond the year 2005, land use patterns will be permanently estab-
lished and further population growth will consist of infilling of estab-
lished urban areas. In the future, it is possible that improved tech-
nology will permit basic changes in public health regulations that could
permit a substantial increase in use of reclaimed water. These
changes could include permission to use dual plumbing within homes,
utilizing reclaimed water not only for irrigation purposes, but for toilet
flush water, laundry water and other presently prohibited non-potable
uses. These types of reuse are not included in the recommended master plan.
Enlargement of the reclamation and reuse facilities could be achieved by
increasing reclamation plant capacity, providing additional storage volume,
and expanding the distribution system.
It is recognized that some approximate schedule would be useful in
overall planning and in marketing of the reclaimed water. Table X-l pre-
sents a tentative schedule, showing the assumed timing of construction
of the various reclamation plants and major portions of the excess
effluent piping system in a matrix format. It should be borne in mind
that these recommendations are for general guidance only, and can be
modified in either direction at any time. h
X-6
I
[
E
i
I
I
I
I
TABLE X-l
RECLAMATION FACILITIES
HYPOTHETICAL SCHEDULE
YEAR BATIQUITOS PALOMAR
AIRPORT
ENCINA LAKE
CALAVERA
HILLS
1980
1985
1990
1995
2000
2005
(1) T - Treatment Plant Construction
A - Advanced Waste Treatment Construction
S - Storage Facility Construction
E - Excess Effluent Construction
IMPLEMENTATION STEPS
In order to implement the reclamation master plan illustrated on
Plate A the following specific steps are recommended to the Carlsbad City
Council:
1.Acceptance of this report and approval of the recommended
reclamation master plan. The plan includes the following:
A.Initial Phase
(1) Batiquitos
a. Plant 0.2 MGD
b. Storage 6.0 MG
c. Excess Effluent Connection
(2) Palomar Airport
a. Plant 2.5 MGD
b. Storage 25.0 MG
c. Excess Effluent Connection
X-7
(3) Lake Calavera Hills
a. Plant 1.2 MGD
b. Subsurface Disposal 0.5 MGD
B. Intermediate Phase Additions
(1) Batiquitos
a. Plant 0.2 MGD (0.4 MGD total)
(2) Palomar Airport
a. Plant 2.5 MGD (5.0 MGD total)
b. Parallel Excess Effluent Connection
c. Storage Reservoir 100 MG
(3) Lake Calavera Hills
a. Subsurface Disposal 0.7 MGD (1.2 MGD total)
(4) Encina
a. Plant 0.9 MGD
C. Ultimate Phase Additions
(1) Batiquitos - none
(2) Palorcar Airport - none
(3) Lake Calavera Hills
a. Excess Effluent Connection
(4) Encina - none
(5) Buena Vista (Optional)
a. Plant 0.5 MGD
b. Excess Effluent Connection
2. Establishment of a reclamation master plan as a formal City plan.
3. Certification of the accompanying Environment Impact Report.
4. Distribution of the reclamation master plan to interested govern-
mental and private agencies.
5. Adoption of ordinances required to implement the plan. These
would include standards for dual pipe systems in new developments
and use of reclaimed water for landscape irrigation within new
developments.
6. Establishment of a policy of receiving and considering specific
proposals for construction of reclamation facilities from developers
and other funding sources.
X-8
7. Instruct staff to develop guidelines for funding individual
projects submitted by private parties.
8. Petition Regional Water Quality Control Board to remove IDS
restrictions from the specific portions of the study area.
This petition should be supported with data indicating that
beneficial use of groundwater in this area is not significant.
9. Encourage, by whatever means are found feasible, the use of
reclaimed water for agricultural and landscape irrigation.
X-9
APPENDIX A
RECLAMATION PLANT DESIGN PRINCIPLES
RECLAMATION PLANT DESIGN FEATURES
The following paragraphs contain a discussion of the design features
which should be incorporated into each reclamation plant. These are in-
tented to serve as a guideline for City staff when reviewing specific
proposals for the construction of reclamation facilities.
WASTE WATER QUALITY
A general discussion of waste water quality appears in the body
of the study. As explained, it is anticipated that the waste water
received at the various reclamation plants will be normal domestic flow.
Based on present planning of the water supply agencies in the area, it is
assumed that a blend of Colorado River water and Northern California water
will be the source of supply. The anticipated waste water quality charac-
teristics were shown in Table III-l.
RECLAIMED WATER QUALITY
As is discussed in detail in the body of the study, it will be neces-
sary to produce a reclaimed water meeting all Regional Water Quality Con-
trol Board and Department of Health standards. A good quality secondary
effluent will be required. It will also be necessary to provide water
with a salt content capable of meeting the ground water objectives in the
various sub-basins of the study area. Unless present Basin Plan water
quality objectives are revised, it will be necessary to comply with the
"one-third" rule for reclaimed water used directly for irrigation purposes.
In addition to regulatory constraints, in order to provide reclaimed water
suitable for general irrigation, design criteria will provide for a maximum
TDS level of 800 mg/1. The critical criteria for reclaimed water quality
are shown in Table III-7.
TREATMENT METHODS
As established in the discussion of treatment methods, only acti-
vated sludge systems will be permitted in the proposed reclamation plants.
All reclamation plants shall employ aeration systems providing for a
complete mix of the aeration tank. Plants with a capacity of up to 1.5
MGD, or less, will be required to provide extended aeration systems. For
purposes of this program, extended aeration is defined as any system
having an aeration volume equal to a 24-hour flow with facilities for
adding adequate oxygen to permit the complete stabilization of the organic
matter in the waste water. Oxygen may be added either by a diffused air
system, mechanical aerators, or such other methods as may be approved.
Pre-engineered "package plants" will be considered if they provide all of
-the necessary appurtenant equipment, and if they incorporate adequate
flexibility in the operating procedures. Oxidation ditches are another
type of extended aeration plant which will be considered if the site is
suitable.
Plants with a capacity in excess of 1.5 MGD shall be of the conven-
tional activated sludge type having treatment tank volumes with a minimum
of six hours detention time. Primary settling tanks will not be manda-
tory if adequate aeration and secondary settling facilities are provided.
Only conventional systems will be permitted. No contact stabilization, or
other modifications of the conventional activated sludge process, will be
considered.
k
A-2
SLUDGE HANDLING FACILITIES
Each reclamation plant shall provide complete sludge handling cap-
ability, including return activated sludge (RAS), waste activated sludge
(WAS), digestion, and sludge dewatering. Separate RAS and WAS pumping
capability shall be provided, together with adequate standby or cross-
over facilities so that both systems are operational with any single pump
out of service.
Only aerobic digestion systems will be permitted. Adequate oxygena-
tion equipment, either diffused air or mechanical aeration, shall be
utilized. For extended aeration systems, the digester can be considered
a holding tank for excess sludge. It shall, however, be provided with
sufficient oxygen to completely reduce the organic material in the WAS
and to assure aerobic conditions in the digester-holding tank at all
times. Conventional activated sludge systems shall be provided with di-
gesters capable of completely reducing and storing WAS.
Dewatering facilities capable of producing a dewatered sludge with
a moisture content of no greater than 85% shall be provided. In general,
mechanical dewatering is preferred.
The sludge handling facilities shall be designed so that in the
event that Encina provides regional sludge handling capability, the facil-
ities at the individual reclamation plants can be maintained on a standby
basis, ready for immediate use if problems should develop at Encina.
A-3
BACK-UP ODOR CONTROL FACILITIES
Each reclamation plant shall be designed so as to minimize any pos-
sibility of odor resulting from normal operation of the plant. The intent
is to provide any and all odor control systems or equipment in addition
to conservative design.
In order to provide complete assurance of an odor-free operation,
backup odor control facilities shall be included in the design of all
plants. These will, in general, include the enclosure of all units and
equipment where odors could originate as a result of malfunction of the
treatment process, and the exhausting and scrubbing of all air from these
enclosed areas. Additional backup odor control facilities as may be
found desirable by City staff shall be included in the design.
REDUNDANT TREATMENT UNITS
All reclamation plants will be subject to the requirements of Title
22. These requirements include a Compliance Report, prepared by the
design engineer, indicating the provision of redundant treatment units,
or the ability of the plant to operate with any single unit of a
multiple-unit system out of service. It is not considered necessary to
provide complete redundancy by the construction of extra standby treatment
units. However, a detailed analysis of the loading rates and the probable
effluent quality resulting from any short-term overloading shall be in-
cluded in the initial presentation of any reclamation plant proposal.
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A-4
AESTHETIC TREATMENT
It is recognized that the reclamation plants proposed in this study
will be, for the most part, constructed in areas readily accessible to
the public. For this reason, complete aesthetic treatment will be required.
Depending upon the exact location and exposure of the plant, landscaping
and architectural treatment of the exterior of the plant are considered
a minimum. Plants which are visible from higher elevations must consider
the aesthetic treatment of the interior of the plant as well as the
periphery.
MISCELLANEOUS FEATURES
An adequate office and work space shall be provided at each plant
location. Potable water, toilet, and lavatory facilities will be re-
quired. It will not, however, be necessary to provide a locker room and
shower facilities at each plant.
It is anticipated that a central laboratory will be provided,
either at Encina or some other location, for the carrying out of chemical
tests. Therefore, no laboratory will be required at the individual re-
clamation plants. However, a small space close to a potable water supply
shall be provided, with a cabinet for holding glassware and sample
bottles. This facility will be utilized for simple tests and the handl-
ing of samples taken at the plant.
All plant sites shall be fenced and provided with security lighting.
The lighting shall be incorporated into the architectural aesthetic
treatment of the plant. Vehicular access shall be provided to each re-
clamation plant. Three automobile-size parking spaces shall be provided
inside the plant site.
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A-5
Each reclamation plant shall be provided with a sign, or such
other identifying information as may be required by the City. A standard
method of identifying reclamation plants will be developed by City staff.
It is anticipated that this will, in all probability, take the form of an
architecturally treated major sign, or other identifying marker, with an
explanation of the purpose of the facility.
Standby electric power shall be provided at each site. An automatic
transfer switch and start-up circut will be used to activate the generator.
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-6