HomeMy WebLinkAboutR-10893 APPROVING A NEGATIVE DECLARATION (EID 1455-2018) AND AMENDMENTS TO THE WATER AND WASTEWATER MANAGEMENT ELEMENT OF THE GENERAL PLAN (GENP-1454-2018)RESOLUTION NO. 10893 (2018 Series)
A RESOLUTION OF THE CITY COUNCIL OF THE CITY OF SAN LUIS
OBISPO, CALIFORNIA APPROVING A NEGATIVE DECLARATION
(EID 1455-2018) AND AMENDMENTS TO THE WATER AND
WASTEWATER MANAGEMENT ELEMENT OF THE GENERAL PLAN
(GENP-1454-2018)
WHEREAS, State law requires cities and counties to adopt a General Plan; and
WHEREAS, the Water and Wastewater Management Element of the City of San Luis
Obispo City General Plan was last updated in 2016 in compliance with State law; and
WHEREAS, a periodic update of the Water and Wastewater Management Element is
necessary for the information to remain current; and
WHEREAS, the City of San Luis Obispo has prepared the 2018 Water and Wastewater
Management Element to address a reduction is safe annual yield from Whale Rock and Salinas
reservoirs and update other background information in the Element; and
WHEREAS, the 2018 Water and Wastewater Management Element was evaluated in
accordance with the California Environmental Quality Act pursuant to an initial environmental
study (EID 1455-2018) and the Community Development Director has prepared a negative
declaration of environmental impact; and
WHEREAS, the Planning Commission, held a hearing on April 11, 2018 and adopted a
resolution recommended the City Council approve a Negative Declaration (EID 1455-2018) and
adopt the proposed amendments to the General Phan, Water and Wastewater Management Element
(GPA 1454-2018).
NOW, THEREFORE, BE IT RESOLVED by the Council of the City of San Luis Obispo
as follows:
SECTION 1. Finding. The City Council, after considering the 2018 Water and
Wastewater Management Element, environmental determination, staff recommendations, public
testimony and correspondence, and reports thereon, finds that proposed modifications to the Water
and Wastewater Management Element is consistent with the General Plan.
SECTION 2. Environmental Determination. In compliance with the California
Environmental Quality Act (CEQA), staff prepared an Initial Study, Negative Declaration (EID
1455-2018) to analyze the potential environmental impacts of the proposed amendment to the
WWME. The City Council hereby approves the Negative Declaration and directs staff to file a
Notice of Determination.
R 10893
Resolution No. 10893 (2018 Series)
Page 2
SECTION 3. Approval of the 2018 Water and Wastewater Management Element. The
City Council hereby adopts the amendments to the 2018 Water and Wastewater Management
Element, as set forth in Exhibit A attached hereto and incorporated herein by this reference.
Upon motion of Vice Mayor Christianson, seconded by Council Member Rivoire, and on the
following roll call vote:
AYES: Council Members Gomez, Pease and Rivoire,
Vice Mayor Christianson and Mayor Harmon
NOES: None
ABSENT: None
The foregoing resolution was adopted this 15`h day of May 2018.
Mayor Ueidi flarmon
ATTEST:
�4u
Teresa Purrington,
City Clerk
APPROVED AS
J.,CfiYi`stine Dietrick
City Attorney
IN WITNESS WHEREOF, I have hereunto set my hand and affixed the official seal of the City
of San Luis Obispo, California, this 1%6�'- day of
Teresa Purrington,
City Clerk
R 10893
Adopted: February 24, 1987
Last Revised: May 15, 2018
(Council Resolution No. 10893, 2018)
Resolution No. 10893 (2018 Series)
EXHIBIT A
Chapter 8
Page 8-2
Please see the next page.
Resolution No. 10893 (2018 Series)
EXHIBIT A
Water and Wastewater Element
Page 8-3
CHAPTER 8 WATER AND WASTEWATER
TABLE OF CONTENTS
INTRODUCTION ........................................................................................................................................................... 8-5
A. WATER MANAGEMENT ...................................................................................................................................... 8-6
INTRODUCTION ................................................................................................................................................... 8-6
A 1.0 Background ............................................................................................................................................. 8-6
A 1.1 Purpose ................................................................................................................................................... 8-6
MULTI-SOURCE WATER SUPPLY ..................................................................................................................... 8-7
A 2.0 Background ............................................................................................................................................. 8-7
A 2.1 Goal ........................................................................................................................................................ 8-9
A 2.2 Policies .................................................................................................................................................. 8-10
A 2.3 Programs .............................................................................................................................................. 8-10
WATER RESOURCE AVAILABILITY ................................................................................................................ 8-11
A 3.0 Background ........................................................................................................................................... 8-11
A 3.1 Goal ...................................................................................................................................................... 8-14
A 3.2 Policies .................................................................................................................................................. 8-14
A 3.3 Programs .............................................................................................................................................. 8-16
SILTATION .......................................................................................................................................................... 8-15
A 4.0 Background ........................................................................................................................................... 8-15
A 4.1 Goals ..................................................................................................................................................... 8-16
A 4.2 Policies .................................................................................................................................................. 8-16
A 4.3 Programs .............................................................................................................................................. 8-16
WATER SUPPLY ACCOUNTING AND DEMAND PROJECTION .................................................................... 8-17
A 5.0 Background ........................................................................................................................................... 8-17
A 5.1 Goals ..................................................................................................................................................... 8-18
A 5.2 Policies .................................................................................................................................................. 8-18
A 5.3 Programs .............................................................................................................................................. 8-18
WATER CONSERVATION ................................................................................................................................. 8-19
A 6.0 Background ........................................................................................................................................... 8-19
A 6.1 Goal ...................................................................................................................................................... 8-20
A 6.2 Policies .................................................................................................................................................. 8-20
A 6.3 Programs .............................................................................................................................................. 8-20
RECYCLED WATER ........................................................................................................................................... 8-21
A 7.0 Background ........................................................................................................................................... 8-21
A 7.1 Goals ..................................................................................................................................................... 8-23
A 7.2 Policies .................................................................................................................................................. 8-23
A 7.3 Programs .............................................................................................................................................. 8-23
B. WASTEWATER MANAGEMENT ....................................................................................................................... 8-24
INTRODUCTION ................................................................................................................................................. 8-24
B 1.0 Background ........................................................................................................................................... 8-24
B 1.1 Purpose ................................................................................................................................................. 8-24
WASTEWATER SERVICE.................................................................................................................................. 8-25
B 2.0 Background ........................................................................................................................................... 8-25
B 2.1 Goal ...................................................................................................................................................... 8-25
B 2.2 Policies .................................................................................................................................................. 8-25
B 2.3 Programs .............................................................................................................................................. 8-26
WASTEWATER TREATMENT ........................................................................................................................... 8-27
B 3.0 Background ........................................................................................................................................... 8-27
B 3.1 Goals ..................................................................................................................................................... 8-27
B 3.2 Policies .................................................................................................................................................. 8-27
B 3.3 Programs .............................................................................................................................................. 8-27
Resolution No. 10893 (2018 Series)
EXHIBIT A
Chapter 8
Page 8-4
COLLECTION SYSTEM ..................................................................................................................................... 8-28
B 4.0 Background ........................................................................................................................................... 8-28
B 4.1 Goal ...................................................................................................................................................... 8-30
B 4.2 Policies .................................................................................................................................................. 8-30
B 4.3 Programs .............................................................................................................................................. 8-30
LIST OF FIGURES
Figure 1 Multi Source Water Supply .................................................................................................................. 8-8
Figure 2 Recycled Water Master Plan Area and Distribution System ............................................................. 8-22
Figure 3 Capacity Constrained Areas .............................................................................................................. 8-26
Figure 4 Inflow and Infiltration Illustrated ......................................................................................................... 8-29
LIST OF TABLES
Table 1. City Water Resource Availability ....................................................................................................... 8-11
Table 2. Annual Recycled Water Availability based on Influent Flow ............................................................. 8-14
Table 3. Whale Rock Reservoir Capacity Change .......................................................................................... 8-15
Table 4. Reservoir Storage Capacity ............................................................................................................... 8-16
Table 5. Water Supply Accounting .................................................................................................................. 8-17
Table 6. Highest Average Daily Flows to the Water Resource Recovery Facility, 2006-2017 ....................... 8-29
Resolution No. 10893 (2018 Series)
EXHIBIT A
Water and Wastewater Element
Page 8-5
INTRODUCTION
The City's General Plan guides the use and protection of various resources to meet community purposes. It reflects
consensus and compromise among a wide diversity of citizens' preferences, within a framework set by State law. The
General Plan contains elements that address various topics.
The City decided to adopt an element addressing water resources and wastewater services because of the vital role of
these resources and the far-reaching impacts of water policies on community growth and character. This element
translates the Land Use Element's capacity for development into potential demand for water supply and wastewater
services. This element outlines how the City plans to provide adequate water and wastewater services for its citizens,
consistent with the goals and policies of other General Plan elements.
Before adopting or revising any General Plan element, the Planning Commission and the City Council must hold public
hearings. The City publishes notices in the local newspaper and on the City’s website to let citizens know about the
hearings at least ten days before they are held. Also, the City prepares environmental documents to help citizens
understand the expected consequences of its planning policies before the hearings are held.
Anyone may suggest or apply for amendments to General Plan elements.
Resolution No. 10893 (2018 Series)
EXHIBIT A
Chapter 8
Page 8-6
A. WATER MANAGEMENT
INTRODUCTION
A 1.0 Background
The original Water and Wastewater Management Element was adopted in 1987 around the time the City
experienced a severe drought period which lasted from 1986 to 1991. During this point in time mandatory water
use restrictions were instituted and restrictions on new development were imposed. Following this period, the
City pursued additional water supplies to meet the existing water needs of the community, as well as to fulfill the
goals of the General Plan. The policies in the Water Management section of the Element were written in a
manner to address the water scarcity issues the City was facing. With the addition of the Nacimiento Water
Project to the City’s water portfolio, the City has an adequate water supply to serve the community’s existing and
future water needs as defined by the General Plan. The 2010 revisions to the Water and Wastewater
Management Element reflected the change in the water supply situation.
The 2016 revisions to the Water and Wastewater Management Element updated the City’s water resource
availability to include the full allocation of the Nacimiento Reservoir increasing the City’s contractual supply from
3,380 acre feet to 5,482 acre feet annually, updated the daily per capita water use assumption used in water
supply accounting, and incorporated information from the Whale Rock Reservoir Bathymetric Survey and
Volumetric Study completed in 2013.
The 2018 revisions to the Water and Wastewater Management Element provide information from the 2018
update to the City’s safe annual yield model. The update verified historical data, validated and documented
calculations used in the model, incorporated data from the 2006‐2016 drought, and reviewed various climate
change scenarios. The updated data reduced the safe annual yield from Salinas and Whale Rock Reservoirs from
6,940 acre feet to 4,910 acre feet. Updates are also provided to background information related to the
Sustainable Groundwater Management Act and the adoption of the Recycled Water Master Plan in 2017.
A 1.1 Purpose
The Water Management section of the Element includes goals, policies, and programs related to water supply,
demand, and other emerging issues.
Resolution No. 10893 (2018 Series)
EXHIBIT A
Water and Wastewater Element
Page 8-7
MULTI-SOURCE WATER SUPPLY
A 2.0 Background
The City is the sole water purveyor within the city limits. This allows the City to maintain uniformity of water
service and distribution standards, and to be consistent in developing and implementing water policy. As the sole
water purveyor, the City maintains control over water quality, distribution, and service to users of the system, as
well as ensuring consistency with the City's General Plan policies and goals.
The Water Element of the General Plan, first adopted in 1987, identified multiple water projects to meet
projected short and long-term water demand. Having several sources of water avoids dependence on any one
source that may not be available during a drought or other water supply reduction or emergency. There is usually
greater reliability and flexibility if sources are of different types (such as surface water and groundwater) and if
the sources of one type are in different locations (such as reservoirs in different watersheds). In November of
1990, the Council affirmed the multi-source concept.
Consistent with the multi-source concept, the City obtains water from five sources: Salinas Reservoir (Santa
Margarita Lake), Whale Rock Reservoir, Nacimiento Reservoir, recycled water from the City’s Water Resource
Recovery Facility, and groundwater. See Figure 1.
Salinas Reservoir
The Salinas Dam was built in 1941 by the War Department to supply water to Camp San Luis Obispo and,
secondarily, to meet the water needs of the City of San Luis Obispo. The Salinas Reservoir (Santa Margarita Lake)
captures water from a 112-square mile watershed and can store up to 23,843 acre-feet. In 1947, the Salinas Dam
and delivery system was transferred from the regular Army to the U.S. Army Corps of Engineers. Since the late
40s or early 50s, the San Luis Obispo County Flood Control and Water Conservation District has operated this
water supply for the City under a lease from the U.S. Army Corps of Engineers. Water from the reservoir is
pumped through the Cuesta Tunnel (a one-mile long tunnel through the mountains of the Cuesta Ridge) after
which it flows by gravity to the City’s Water Treatment Plant on Stenner Creek Road.
Whale Rock Reservoir
The Whale Rock Reservoir is a 40,662 acre-foot reservoir created by the construction of an earthen dam on Old
Creek near the town of Cayucos. The dam was designed and constructed by the State Department of Water
Resources in 1961 to provide water to the City of San Luis Obispo, Cal Poly State University, and the California
Men’s Colony. The Whale Rock Dam captures water from a 20.3-square mile watershed and water is delivered to
the three agencies through 17.6 miles of 30-inch pipeline and two pumping stations. The City of San Luis Obispo
owns 55.05 percent of the water storage rights at the reservoir. The remaining water storage rights are divided
between the two State agencies with Cal Poly owning 33.71 percent and the California Men’s Colony owning
11.24 percent.
Nacimiento Reservoir
The Nacimiento Reservoir provides flood protection and is a source of supply for groundwater recharge for the
Salinas Valley. It is owned and operated by the Monterey County Water Resources Agency. Since 1959, the San
Luis Obispo County Flood Control and Water Conservation District has had an entitlement to 17,500 acre-feet per
year (AFY) of water from the reservoir for use in San Luis Obispo County. Approximately 1,750 AFY have been
designated for uses around the lake, leaving 15,750 AFY for allocation to other areas within the County of San
Luis Obispo.
Resolution No. 10893 (2018 Series)
EXHIBIT A
Chapter 8
Page 8-8
Figure 1 Multi Source Water Supply
Resolution No. 10893 (2018 Series)
EXHIBIT A
Water and Wastewater Element
Page 8-9
The County completed construction of a 45-mile pipeline project to deliver water from the Nacimiento Reservoir
to five participating agencies and cities in 2010. The City has a contractual entitlement to 5,482 AFY of water from
the project.
Recycled Water
Recycled water is highly treated wastewater approved for reuse by the California Department of Public Health for
a variety of applications, including landscape irrigation and construction dust control. Completed in 2006, the
Water Reuse Project created the first new source of water for the City since 1961 following construction of Whale
Rock Dam. The Project resulted in improvements at the City’s Water Resource Recovery Facility and an initial
eight miles of distribution pipeline. The City’s first delivery of recycled water took place in 2006. The City
estimates demand exists for approximately 1,000 acre feet of recycled water for landscape irrigation and other
approved uses. In addition to use landscape irrigation, the City is examining several alternatives for maximizing
the long-term beneficial use of recycled water. Alternatives include providing groundwater recharge within the
San Luis Obispo Valley Basin for indirect potable reuse (IPR), or direct potable reuse (DPR). Additional information
is provided on recycled water in subsections A 3.0, A 7.0, and B 3.0 of this Element and in the 2017 Recycled
Water Master Plan.
Groundwater
The groundwater basin beneath the City is relatively small and recharges very quickly following normal rainfall
periods. The groundwater basin also lowers relatively quickly during periods of below-average rainfall. Extensive
use of groundwater sustained the City through most of the drought of 1986-1991. The City’s two largest
producing wells were shut down in 1992 and 1993 when elevated nitrate levels were detected. The City stopped
utilizing the Pacific Beach well in April 2015.
The City envisions groundwater playing an important role in ensuring continued resiliency in its water supply
portfolio. The Sustainable Groundwater Management Act (SGMA) is a statewide law that requires local agencies
to adopt groundwater management plans that relate to the needs and resources of their communities. In 2017,
the City became a Groundwater Sustainability Agency (GSA) over the area of the San Luis Obispo Valley
Groundwater Basin, designated by the California Department of Water Resources as a Medium Priority Basin,
that lies beneath and within its jurisdictional boundaries. The San Luis Obispo Valley Groundwater Basin “eligible
entities” (City, County, Golden State Water Company, Edna Ranch Mutual Water Company-East, Varian Ranch
Mutual Water Company, and Edna Valley Growers Mutual Water Company) are all working collaboratively to
comply with SGMA requirements for the entire groundwater basin. The GSA structure includes a Groundwater
Sustainability Commission which is an advisory body to the City Council and the Board of Supervisors. The
Commission consists of one member from the City Council, one County Supervisor and a representative of each
of the identified water companies. The City, County, and eligible entities are required by SGMA to work together
to create Groundwater Sustainability Plans by January 31, 2022.
Private wells are in use in the City, such as the well operated by San Luis Coastal Unified School District at San Luis
Obispo High School. The City’s Laguna Lake Golf Course also has two wells that meet a portion of the irrigation
demand for the course. The remainder of the irrigation demand for the golf course is met using recycled water
from the City’s Water Resource Recovery Facility.
A 2.1 Goal
Ensure a long-term, reliable water supply to meet both current and future water demand associated with
development envisioned by the General Plan.
Resolution No. 10893 (2018 Series)
EXHIBIT A
Chapter 8
Page 8-10
A 2.2 Policies
A 2.2.1 Multi-Source Water Supply
The City shall utilize multiple water resources to meet its water supply needs.
A 2.2.2 Water Service within the City
A. The City will be the only purveyor of water within the City.
B. Appropriate use of privately-owned wells is allowed on individual parcels. The use of the water from
a well shall only be utilized on the parcel on which it is situated.
A 2.3 Programs
A 2.3.1 Work cooperatively on regional water issues and water resource planning (Water Resource Advisory
Committee, Whale Rock Commission, Groundwater Sustainability Commission, etc.).
A 2.3.2 Participate with the County of San Luis Obispo in the Integrated Regional Water Management Plan process.
A 2.3.3 Participate with other appropriate agencies in controlling invasive species which could impact the City’s
water supplies (i.e. quagga mussels).
A 2.3.4 Work with appropriate agencies to minimize water quality impacts from new development and other
activities in the watersheds of the City’s water supplies.
A 2.3.5 Continue to work with the County of San Luis Obispo on the operation and maintenance of Salinas Reservoir
and Nacimiento Water Project.
A 2.3.6 Complete sanitary surveys for the Salinas and Whale Rock Reservoirs every five years.
Resolution No. 10893 (2018 Series)
EXHIBIT A
Water and Wastewater Element
Page 8-11
Water Resource Availability
A 3.0 Background
As described in Section A 2.0, the City has five water resources to meet current and future City water demand:
Salinas Reservoir (Santa Margarita Lake), Whale Rock Reservoir, Nacimiento Reservoir, recycled water from the
City’s Water Resource Recovery Facility, and groundwater. In order to ensure water supply reliability, the City
must determine the amount of water available from these water resources on an annual basis. The method to
determine the available yield from each resource varies based on water right, contractual agreement, or the
amount of water actually supplied.
For Salinas and Whale Rock Reservoirs the term “safe annual yield” is used to define the annual amount of water
available from these two resources. The two reservoirs are operated in a coordinated manner to increase the
available water. In contrast, the “dependable yield” from Nacimiento Reservoir is the contractual amount of
water to which the City has rights. Since Nacimiento Reservoir is operated as a water supply project for Monterey
County, the concept of safe annual yield is not used for the City’s contractual water supply from this source. For
recycled water, the annual amount delivered is counted in the water availability calculation. Though groundwater
is part of the City’s water portfolio the City does not consider this supply in estimating available water resources
to meet community needs at this time.
Another issue the City must address is the potential impact of climate change on the City’s water resources.
Climate change could have a significant impact on future water availability in the form of droughts or increased
siltation in reservoirs as a result of wildland fires which could affect the safe annual yield of the City’s reservoirs.
As data becomes available and research on the topic continues, the City will make adjustments for long-term
impacts to its water supply resources.
The following sections provide more detail about each water resource. Table 1 is a summary of the City’s
available water resources.
City Water Resource Availability
Water Resource 2018 Annual Availability
Salinas Reservoir (Santa Margarita Lake) and
Whale Rock Reservoir 4,910 AF Safe Annual Yield
Nacimiento Reservoir 5,482 AF Contractual Limit
Recycled Water 238 AF 2017 Annual Usage
Siltation to 2060 (500 AF) Policy A 4.2.2
TOTAL 10,130 AF
Note: The quantity of recycled water included as part of the City’s available water resources identified above, is the actual prior year’s recycled
water usage (2017), per Policy A 7.2.2.
Source: City of San Luis Obispo Utilities Department, 2018.
Resolution No. 10893 (2018 Series)
EXHIBIT A
Chapter 8
Page 8-12
Salinas and Whale Rock Reservoirs
For Salinas and Whale Rock Reservoirs the term “safe annual yield” is used to define the quantity of water which
can be withdrawn every year, under critical drought conditions.
The City maintains an Excel‐based model that estimates a safe annual yield based on historical climatic conditions
and reservoir operations. The model uses the historical record of inflow, evaporation, precipitation, and
downstream releases. To determine safe annual yield, the model then calculates the maximum amount that
could be withdrawn each year without drawing the reservoir below its minimum pool constraint.
Salinas Reservoir and Whale Rock Reservoir are located in different climate regions and have differing
characteristics. Whale Rock Reservoir has a larger storage volume than Salinas, but it has a smaller watershed to
provide natural recharge. Salinas Reservoir receives more runoff each year, but experiences higher temperatures
and higher evaporation rates, and spills more frequently than Whale Rock Reservoir. To maximize the available
supply from the two reservoirs, the City has operational strategies that recognize these differences. In general,
the strategies involve withdrawing water from Salinas Reservoir when it is available and using Whale Rock
Reservoir as‐needed to supplement the supply from Salinas.
The City’s safe annual yield model of the two reservoirs was first developed in 1988. At that time, the critical
drought period that controlled the safe annual yield was the 1946‐1951 drought. In 1991, the model was updated
to incorporate the hydrologic conditions experienced during the 1986‐1991 drought. That drought was the most
severe in the historical record to that point and became the new controlling condition for estimating safe annual
yield. The City estimated the combined SAY from the two reservoirs as 6,940 acre‐feet per year (AFY). This
estimate included the anticipated loss of storage volume due to siltation through the year 2010.
In 2017, the City contracted with Water Systems Consulting, Inc. (WSC) to update the safe annual yield model.
The update verified historical data, validated and documented calculations used in the model, incorporated data
from the 2006‐2016 drought, and reviewed various climate change scenarios. Based on the 2017 update, the
City’s safe annual yield, from the coordinated operation of Salinas and Whale Rock Reservoirs is 4,910 acre feet.
This includes reductions due to siltation at both reservoirs to the year. Future losses due to siltation are
addressed in Section 4.0 of this Element.
Nacimiento Reservoir
The “dependable yield” from Nacimiento Reservoir is the contractual amount of water that the City has rights to
from Nacimiento Reservoir. This amount is 5,482 acre-feet per year. The San Luis Obispo County Flood Control
and Water Conservation District (County) has held an entitlement to 17,500 acre-feet of water from Nacimiento
Lake since 1959. Since that time, a small portion has been dedicated for uses in the immediate areas around the
Lake. Several times in the past, the County has evaluated opportunities for utilizing water to meet identified
needs throughout the County. In the early 1990’s, the City was facing dire drought conditions and dwindling
water supplies and was considering building an emergency water supply project on its own to provide a new
water source. The City requested the County allocate 3,000 acre feet to the City on a permanent basis. While the
County denied this request, this triggered the initiation of investigations on a county-wide basis for separate
contracts for use of the available water from Nacimiento Reservoir.
Engineering studies, environmental impact reports, dependable yield analyses, and preliminary design reports
were undertaken in an effort to meet the various water needs within the County. In 2004, the County requested
interested agencies to approve the contractual agreements for participation in the Nacimiento Project. The four
initial project participants included the cities of San Luis Obispo and Paso Robles, the Atascadero Mutual Water
Company, and the Templeton Community Services District. All of these agencies executed participation
agreements with San Luis Obispo County for entitlements of water which totaled 9,630 acre feet. Since 2004, the
Resolution No. 10893 (2018 Series)
EXHIBIT A
Water and Wastewater Element
Page 8-13
County Service Area 10A, which serves the southern portion of Cayucos, has become a project participant (25
AFY). In addition, 1,750 acre-feet was reserved for uses around the lake.
On June 29, 2004, the City Council authorized participation in the Nacimiento Water Project for the delivery of
3,380 acre-feet of water. This amount is considered to be the City’s dependable yield from this water source and
will be utilized to meet existing and future water demands based on analyses prepared during the Nacimiento
Project planning process (“Nacimiento Reservoir Reliability as a Water Source for San Luis Obispo County”, Boyle
Engineering Corporation, October 2002).
In March 2016, the City Council approved the addition of 2,102 acre feet per year from Nacimiento Reservoir. At
that time, the City’s primary water supply and reliability reserve were fully satisfied by other existing water
supplies, so the additional 2,102 acre feet was included in the City’s secondary water supply. Secondary water
supplies are used to meet short-term losses to the City’s water supply due to events such as drought, pipeline
maintenance, and repair of infrastructure. With uncertainty of future climatic conditions, regulation and aging
infrastructure, the additional supply of Nacimiento water to the City’s portfolio reduces pressure on use of water
supplies in the Whale Rock and Salinas reservoirs. It would serve to extend these stored supplies during critical
water shortage periods. With the reduction of safe annual yield identified in the update of the model in 2018, the
additional 2,102 acre feet from the full allocation of Nacimiento Reservoir will be utilized to meet the City’s water
demands over time, as buildout of the General Plan is realized, consistent with the City’s Water Supply
Accounting & Demand Projection policies in Section A 5.2.
Recycled Water
With an average influent flow of 3.30 million gallons per day in 2017, the City’s Water Resource Recovery Facility
produces over 3,000 acre-feet of disinfected tertiary-treated effluent per year. A minimum of 1,807 acre-feet is
discharged to San Luis Obispo Creek annually to provide satisfactory habitat and flow volume for fish species
(steelhead trout) within the San Luis Obispo Creek environment. The balance makes up the City’s available
recycled water resource (See Table 2) which is available for approved uses including:
Landscape and golf course irrigation
Wetlands, wildlife habitat, stream augmentation
Groundwater recharge
Toilet flushing
Vehicle washing
Surface irrigation of orchards and vineyards
Landscape impoundments
Industrial cooling processes
Food crop irrigation
The design phase for the upgrade of the WRRF continues in 2018 to accommodate General Plan buildout and
maximize recycled water production. The upgrade will enable the City to consider potable reuse in the future.
Additional background information on recycled water, as well as applicable goals, policies and programs, is
provided in subsection A 7.0 of the Water Section and subsection B 3.0 of the Wastewater Management Section.
Resolution No. 10893 (2018 Series)
EXHIBIT A
Chapter 8
Page 8-14
Annual Recycled Water Availability based on Influent Flow
Average Influent Flow
to WRRF (MGD)
Treated
Effluent
Produced
(AFY)
Minimum Average
Daily Creek
Release (MGD)1
Minimum
Annual Creek
Release (AFY)
Average Daily
Recycled Water
Availability (MGD)
Annual Recycled
Water Availability
(AFY) 1
2017 Average
Flow 3.30 3,696 1.6129 1,807 1.69 1,889
Future Flow at
WRRF Design
Capacity
5.4 5,966 1.6129 1,807 3.79 4,159
NOTES:
1. 2017 data was derived from WRRF average monthly influent data. Future annual recycled water volume is based on the design capacity of
the WRRF of 5.4 mgd in the design phase in 2018.
Source: City of San Luis Obispo Utilities Department, 2016.
A 3.1 Goal
Manage the City’s water resources to meet the current and future water demand requirements associated with
development envisioned by the General Plan.
A 3.2 Policies
A 3.2.1 Basis for Planning
The City will plan for future development through the Land Use Element taking into consideration available
water resources from the Salinas, Whale Rock, and Nacimiento Reservoirs and recycled water.
A 3.2.2 Coordinated Operation
The City will coordinate the operation of the Salinas, Whale Rock, and Nacimiento Reservoirs to maximize
available water resources.
A 3.2.3 Groundwater
The City will continue to use groundwater to enhance the resiliency of the City’s water supply portfolio.
A 3.3 Programs
A 3.3.1 An update on the water resource availability will be presented to the City Council as part of an annual Water
Resources Status Report.
A 3.3.2 The City will update the safe annual yield computer model for Salinas and Whale Rock Reservoirs following
severe drought periods to determine if any changes are necessary to the safe annual yield amount.
A 3.3.3 The City will monitor ongoing research on the potential for long-term impacts associated with climate change
to water supply resources.
Resolution No. 10893 (2018 Series)
EXHIBIT A
Water and Wastewater Element
Page 8-15
SILTATION
A 4.0 Background
Siltation at reservoirs is a natural occurrence that can reduce the storage capacity over long periods. The
reduction of available storage reduces the safe annual yield of the reservoirs. Siltation at reservoirs varies
depending on factors such as rainfall intensity and watershed management practices. Numerous studies and
reports addressing siltation at Salinas Reservoir have been completed. The Whale Rock Reservoir Bathymetric
Survey and Volumetric Study was completed in May 2013.
During the drought period ending in 1991, water at Salinas Reservoir fell to record low levels. Recognizing the
unique opportunity presented by the low water level, the County of San Luis Obispo contracted with a local
engineering consultant to provide an aerial survey of the lake and prepare revised storage capacity information.
Early studies indicated average annual siltation rates from 23 acre-feet per year to 34 acre-feet per year. The
study done by the U.S. Geological Survey in 1975 estimated that the siltation rate was approximately 82 acre-feet
per year. The 1990 analysis conducted by the County of San Luis Obispo indicates that the siltation rate is on the
order of 40 acre-feet per year.
It should be noted that siltation impacts to the reservoirs are a long-term impact to the resources and should be
considered in the City’s long range plans for adequate water resources. At an annual siltation rate of 40 AFY at
each reservoir, it would take approximately 530 years to fill up the Salinas Reservoir and 960 years to fill up
Whale Rock Reservoir. Siltation does not occur uniformly over time but the situation should continue to be
monitored into the future.
The purpose of the 2013 bathymetric survey and volumetric study at Whale Rock Reservoir was to determine the
level of siltation that has occurred in the reservoir since the dam’s completion in 1961. The study concluded that
sedimentation has reduced reservoir capacity by 4.2 percent in 52 years as shown in Table 3 and 4.
Whale Rock Reservoir Capacity Change
1961 Capacity: 40,662 Acre-Ft @ Spillway ELV 216.0 NGVD29
2013 Capacity: 38,967 Acre-Ft @ Spillway ELV 218.3 NAVD88
Capacity Loss due to
Siltation: 1,695 Acre-Ft
Difference in Years: 52 Years
Siltation Rate: 32.6 Acre-Ft/Year
Percentage Capacity Loss: 4.2%
Source: Whale Rock Reservoir Bathymetric Survey and Volumetric Study, 2013.
The safe annual yield from the two reservoirs will be continually reduced as a result of siltation. The City’s
computer model is used to calculate the reduction in safe annual yield from Salinas and Whale Rock reservoirs to-
date, which is reflected in the safe annual yield amount in Section A 3.0 which accounts for estimated siltation
losses to 2017.
Since the storage capacity for Salinas Reservoir was last estimated in 1990, the annual loss of 40 acre-feet per
year can be applied from that date.
Resolution No. 10893 (2018 Series)
EXHIBIT A
Chapter 8
Page 8-16
Reservoir Storage Capacity
Agency %
Entitlement
Original
Storage
Capacity
(AF)
Revised
Storage
Capacity
(AF)
Difference
(AF)
Revised Total
Available
Water * (AF)
City of San
Luis Obispo 55.05 22,384 21,451 933 20,350
Cal Poly 33.71 13,707 13,136 571 12,462
CMC 11.24 4,570 4,380 191 4,155
Total 100 % 40,662 AF 38,967 AF 1,695 AF 36,967 AF
Source: Whale Rock Reservoir Bathymetric Survey and Volumetric Study, 2013.
*Total Available Water is agency share of reservoir storage capacity minus agency proportional share of
minimum pool requirements.
The estimated loss in storage capacity for Salinas Reservoir between 1990 and 2010 is 800 acre-feet. The loss at
Whale Rock Reservoir between 1961 and 2013 was 1,695 acre-feet. Based on these reduced storage capacities,
the computer model was used to estimate the safe annual yield from the combined operation of the two
reservoirs. With an estimated loss of 40 acre-feet per year at each reservoir, the total safe annual yield from the
two reservoirs is estimated to be reduced by 10 acre-feet per year.
A 4.1 Goals
A 4.1.1 Accurately account for siltation in the Salinas and Whale Rock Reservoirs.
A 4.1.2 Recognize and account for future projected water losses due to siltation at Salinas and Whale Rock
Reservoirs.
A 4.2 Policies
A 4.2.2 Accounting for Future Siltation
The City will account for estimated safe annual yield losses at Salinas and Whale Rock Reservoirs through
2060 by deducting 500 acre feet of available water supplies to account for these future losses. The siltation
rate will be updated as information becomes available from subsequent siltation analyses.
A 4.3 Programs
A 4.3.1 Work cooperatively with other agencies and/or watershed management groups, including the County of San
Luis Obispo and Resource Conservation Districts, implementing best management practices (BMPs) to reduce
erosion and subsequent siltation consistent with other City watershed management goals and water quality
objectives included in the Conservation and Open Space Element.
A 4.3.2 Continue public education and outreach to property owners in the watersheds above the reservoirs to
encourage practices that reduce erosion and other practices that could impact siltation or water quality in
the reservoirs.
A 4.3.3 Consider periodic siltation studies at each reservoir to evaluate and document the impacts associated with
siltation.
A 4.3.4 An update on siltation at the City’s reservoirs will be provided to the City Council as part of the annual Water
Resources Status Report.
Resolution No. 10893 (2018 Series)
EXHIBIT A
Water and Wastewater Element
Page 8-17
WATER SUPPLY ACCOUNTING AND DEMAND PROJECTION
A 5.0 Background
The City is located in a Mediterranean climate that is prone to drought. As a result, the City has in the past
experienced serious water supply deficits. In 1991, during an extended drought, the community was within 18
months of running out of water in Salinas and Whale Rock Reservoirs. In fact, Salinas Reservoir was below
minimum pool and was not available to the City toward the end of this drought period. In 1996, citizens voted to
incorporate Section 909 into the City’s Charter identifying a water reliability reserve. In an effort to reduce the
impacts of drought on the community, the City Council has enacted numerous water policies to strengthen its
water resources portfolio. The City will account for water supplies necessary to meet three specific community
needs: 1) primary water supply, 2) reliability reserve, and 3) secondary water supply.
1. Primary water supply is the amount needed to meet the General Plan build-out of the City.
2. Reliability reserve provides a buffer for future unforeseen or unpredictable long-term impacts to the City’s
available water resources such as loss of yield from an existing water supply source and impacts due to
climate change.
3. Secondary water supply is the amount needed to meet peak water demand periods or short-term loss of
City water supply sources. The City’s secondary water supply is identified as any water supply resources
above those needed to meet the primary water supply and reliability reserve.
In order to support growth projections and other goals of the General Plan, the City must project how much
water will be needed to serve residents, businesses, and other users. This can be done by using different
methods, all of which involve assumptions about future usage rates and the numbers and types of users expected
in the future. There will always be some uncertainty in estimating development capacity (such as the number of
dwellings or residents) as well as the usage per customer type (such as acre-feet per dwelling or per resident).
The estimating method must use reasonable assumptions, based on experience, to assure an adequate level of
water supply while not overstating demands.
To project the City’s primary water supply and reliability reserve into the future the City will use 117 gpcd which is
the maximum allowed per capita water use under Senate Bill X7-7. This water use rate is used with the City’s
build-out population and current population to project the primary water supply and reliability reserve. The City’s
remaining water resources make up secondary water supply.
Table 5 Water Supply Accounting
Proposed Water Supply Accounting and Demand Projections
(City Buildout Population * 117 gpcd * 365
days) / 325,851 gallons =
Primary Water Supply
+
20% of Current City
Population * 117 gpcd * 365
days) / 325,851 gallons =
Reliability Reserve
+
All Remaining Supplies
Secondary Water Supply
= Annual
Availability
Notes:
1. The “Total” water supply is identified in Table 1. It includes safe annual yield from Salinas and Whale Rock Reservoirs, contractual
limit from Nacimiento Reservoir, annual recycled water usage for 2017, and deducts siltation losses at Salinas and Whale Rock
Reservoirs to 2060.
2. Primary Water Supply is calculated using the City’s buildout population and the water use rate of 117 gallons per capita per day
per policy A 5.2.2.
3. Reliability Reserve was calculated using the City’s population and 20 percent of the water use rate of 117 gallons per capita per
day, per policy A 5.2.3.
4. Secondary Water Supply includes the remaining water resources, identified in Table 1, per policy A 5.2.4.
Source: City of San Luis Obispo Utilities Department, 2018.
Resolution No. 10893 (2018 Series)
EXHIBIT A
Chapter 8
Page 8-18
A 5.1 Goals
A 5.1.1 Identify and meet the City’s multi- source water supply needs.
A 5.1.2 Accurately forecast future water demand for planning purposes.
A 5.2 Policies
A 5.2.1 Water Use Rate
The City will utilize the per capita water use rate allowed by Senate Bill X7-7 for projecting future potable
water demand established as 117 gallons per capita per day.
A 5.2.2 Primary Water Supply
The City shall establish the amount of water needed for General Plan build-out using the water use rate
established in Policy A 5.2.1 multiplied by the projected General Plan build-out population identified in the
Land Use Element.
A 5.2.3 Reliability Reserve
The City will establish a reliability reserve that is 20-percent of the water use rate established in Policy A 5.2.1
multiplied by the current population. The water supply designated as the reliability reserve may not be used
to serve future development.
A 5.2.4 Secondary Water Supply
After accounting for primary water supply and a reliability reserve, any remaining water supplies shall be
utilized for meeting short-term water supply shortages or peak water demands.
A 5.2.5 Paying for Water for New Development
New development shall pay its proportionate or “fair share” for water supplies, expanded treatment and
distribution system capacity and upgrades.
A 5.3 Programs
A 5.3.1 An update on water supply accounting and demand projections will be presented to the City Council as part
of the annual Water Resources Status Report.
A 5.3.2 The City will conduct periodic updates to water development impact fees.
A 5.3.3 Prepare and update the Urban Water Management Plan every five years as required by the State.
A 5.3.4 Analyze and prepare water supply assessments for large new developments in accordance with State law.
A 5.3.5 Analyze the impacts of water efficiency programs and services to reduce overall water demand within the
City.
Resolution No. 10893 (2018 Series)
EXHIBIT A
Water and Wastewater Element
Page 8-19
WATER CONSERVATION
A 6.0 Background
Water conservation was first referenced as a part of the City's water management policy in 1973. In 1985, the
City adopted the Annual Water Operational Plan policy establishing water conservation as a means of extending
water supplies during projected water shortages. Since 1985, many technological and philosophical changes have
occurred which are proving water conservation to be both a short-term corrective measure for immediate water
supply shortages and a long-term solution to water supply reliability.
Because of the experience during the drought of 1986 to 1991, the City developed a Water Shortage Contingency
Plan (Plan) to deal with immediate, short-term water shortages. The Plan is designed to require mandatory
actions when there is a projected five year supply of water remaining from available water resources. The Plan
uses water allocations based on customer classification as a means to decrease water use during critical water
shortages. For instance, residential customers are given a water allocation based on the average water use for
multi- or single-family households having three occupants. If there are more residents, additional water may be
allocated with sufficient proof. Commercial customers are allocated water either by a reduction based on their
historical water use or by the average water use by business type. The Plan is also a required component of the
City’s Urban Water Management Plan which is updated every five years per State Water Code.
The Water Conservation Act of 2009, Senate Bill X7-7 (SB X7-7), was incorporated into the California Water Code
in 2009. The legislation directs urban water suppliers to adopt one of four methods to determine their urban
water use target. The method selected by the City corresponds to the Central Coast hydrologic region. The
Central Coast region’s 2020 target of 117 gallons per capita per day is the lowest in the state.
In terms of water supply reliability, the City was one of the original signatories to the Memorandum of
Understanding Regarding Urban Water Conservation (MOU) and has actively pursued the implementation of the
water efficiency best management practices (BMPs) prescribed in the MOU. The MOU was a negotiated
agreement between water purveyors statewide and environmental organizations on how best to utilize the
State’s water resources by incorporating conservation into their water management practices.
The BMPs have been developed over the years by water purveyors, environmental groups, and industry
stakeholders. They represent the best available water conservation practices based on research and experience
and include:
Water conservation pricing and rate structures
Technical assistance for water customers
Incentives for indoor and outdoor water saving technologies
Public information and outreach
Water audits
Additionally, the City has adopted the Ahwahnee Principles as part of the General Plan’s Conservation and Open
Space Element (COSE). The water conservation components of the principles align with both the indoor and
outdoor water conservation BMPs.
The City continues to update its water conservation efforts in response to changing water demand, supplies,
technology, and economic conditions.
Resolution No. 10893 (2018 Series)
EXHIBIT A
Chapter 8
Page 8-20
A 6.1 Goal
The efficient use of the City’s water resources to protect both short- and long-term water supply reliability.
A 6.2 Policies
A 6.2.1 Long-term Water Efficiency
The City will implement water-efficiency programs which are consistent with accepted best management
practices and comply with any State-mandated water use reductions.
A 6.2.2 Short-term Water Shortages
Mandatory water conservation measures as described in the City’s Water Shortage Contingency Plan,
included in the City’s Urban Water Management Plan, may be implemented when the City's water supplies
are projected to last five years or less.
A 6.3 Programs
A 6.3.1 Work cooperatively with other San Luis Obispo County water agencies to identify cooperative water
efficiency measures that can be implemented in each jurisdiction.
A 6.3.2 Participate in State and regional water conservation efforts and research and development opportunities.
A 6.3.3 Implement the Water Shortage Contingency Plan, included in the City’s Urban Water Management Plan, as
required.
Resolution No. 10893 (2018 Series)
EXHIBIT A
Water and Wastewater Element
Page 8-21
RECYCLED WATER
A 7.0 Background
Water recycling was envisioned as part of the City’s overall water supply strategy since the 1980’s. In 1994, the
City completed a major capital improvement project at the Water Resource Recovery Facility that included
addition of tertiary treatment and other unit processes required to meet stringent effluent quality limits intended
to protect and enhance the receiving waters of San Luis Obispo Creek. While a municipal water reuse program
was envisioned at the time of this upgrade, the City did not receive regulatory approvals for diversion of treated
effluent for off-site landscape irrigation and other approved uses until 2002.
Recycled water deliveries began in October 2006. Additional sites continue to be connected to the recycled water
distribution system through retrofits of existing irrigation systems as well as the irrigation systems associated
with new development in the area. In the future, recycled water will be delivered to development in the Airport,
Margarita, and Orcutt specific plan areas and is being considered with development proposals for the Avila
Ranch, San Luis Ranch, and Madonna on LOVR specific plans. Recycled water will be used for the irrigation of
parks, streetscape, and median landscaping, common area (homeowners association) landscaping, and
landscaping in commercial centers, industrial areas, and business parks.
The City’s 2017 Recycled Water Master Plan identifies the areas of the City to be served with recycled water (See
Figure 2, Recycled Water Master Plan Area and Distribution System), as well as potential customers and
anticipated future recycled water demand.
Resolution No. 10893 (2018 Series)
EXHIBIT A
Chapter 8
Page 8-22
Figure 2 Recycled Water Master Plan Area and Distribution System
Resolution No. 10893 (2018 Series)
EXHIBIT A
Water and Wastewater Element
Page 8-23
A 7.1 Goals
A 7.1.1 Maximize recycled water use for all approved purposes.
A 7.2 Policies
A 7.2.1 Recycled Water Supply
The City will make available recycled water to substitute for existing potable water uses as allowed by law
and to supply new non-potable uses.
A 7.2.2 Accounting for Recycled Water
The City will add total recycled water usage from the prior year to the City’s water resource availability on an
annual basis.
A 7.3 Programs
A 7.3.1 Expand the recycled water distribution system to serve customers in the Recycled Water Master Plan area.
A 7.3.2 Review development proposals for projects within the Recycled Water Master Plan area to ensure recycled
water is utilized for appropriate uses.
A 7.3.3 Annual recycled water usage will be presented to the City Council as part of the annual Water Resources
Status Report and will be added to the City’s water resource availability per policy A 3.2.1.
A 7.3.4 Consider the potential to deliver available recycled water supplies to customers outside the city limits,
including analysis of policy issues, technical concerns, and cost recovery, provided it is found to be consistent
with the General Plan.
A 7.3.5 Continue to explore potable reuse consistent with statewide regulations.
Resolution No. 10893 (2018 Series)
EXHIBIT A
Chapter 8
Page 8-24
B. WASTEWATER MANAGEMENT
INTRODUCTION
B 1.0 Background
The Wastewater Management section was first incorporated into the Water and Wastewater Management
Element of the General Plan in 1987. The City owns and operates, under regulatory permits, a wastewater
collection system and a water resource recovery facility that produces recycled water. In order to adequately
maintain the systems, meet the needs of the community, and meet increasingly stringent regulations the City
implements infrastructure replacement and upgrade projects at the Water Resource Recovery Facility and
throughout the wastewater collection system. It also has a pretreatment program.
The 2018 revisions include updated data related to the City’s wastewater flows.
B 1.1 Purpose
This section of the Water and Wastewater Management Element establishes goals, policies, and programs to
ensure provision of adequate sanitary sewer infrastructure and wastewater treatment capacity to accommodate
existing and future development in order to protect public health, human safety, and the environment.
Resolution No. 10893 (2018 Series)
EXHIBIT A
Water and Wastewater Element
Page 8-25
WASTEWATER SERVICE
B 2.0 Background
The City is the sole provider of wastewater service within the City. The service provides collection and treatment
for residential, commercial, and industrial users on properties within the city limits. In 2018, the number of
service connections is estimated to be 12,000. Through agreement, the City also provides service to the San Luis
Obispo campus of California Polytechnic State University (Cal Poly) and the County of San Luis Obispo Airport.
The collection system is primarily a gravity flow system. Where gravity flow is not feasible due to the topography,
wastewater lift stations and pressurized force mains are used to move wastewater to the City’s Water Resource
Recovery Facility on Prado Road. Sewer pipelines measure from six inches to 48 inches in diameter.
The City completed a two-year Flow Monitoring and Inflow/Infiltration Study in 2012. Using data from this
Study, pipeline condition data from its asset management database, and growth assumption from the General
Plan’s Land Use (2014) and Housing (2015) elements, the City completed hydraulic modeling and its
Wastewater Collection System Infrastructure Renewal Strategy in 2016. The Renewal Strategy identified a
prioritized list of capital projects to address the City’s aging infrastructure. The Renewal Strategy also
identified capacity constrained areas during wet weather events due to inflow and infiltration, shown in Figure
3. Inflow and infiltration is discussed further in section B.4.0.
The Water Resource Recovery Facility is designed for an average dry-weather flow of 5.1 million gallons per day
(mgd). Instantaneous peak flows exceeding 20 mgd are not uncommon during storm events due to infiltration
and inflow into the wastewater collection system, discussed further in subsection B 4.0. As the City grows to its
build-out population outlined in the Land Use Element, the average dry-weather flow of wastewater is expected
to reach 5.4 mgd. In 2018, design for the expansion of the Water Resource Recovery Facility to accommodate
General Plan buildout is underway. When the WRRF is expanded in the future it will have a treatment capacity of
5.4 mgd.
B 2.1 Goal
Adequate wastewater collection and treatment service to meet the long-term needs of the City.
B 2.2 Policies
B 2.2.1 Service Outside the City Limits
To receive City wastewater service, property must be annexed to the City. The City Council may authorize
exceptions to this policy provided it is found to be consistent with the General Plan.
B 2.2.2 Service Capacity
The City's wastewater collection system and Water Resource Recovery Facility shall support population and
related service demands consistent with the General Plan.
B 2.2.3 Wastewater Service for New Development
New development shall pay its proportionate or “fair share” of expanded treatment and collection system
capacity and upgrades. New development will only be permitted if adequate capacity is available within the
wastewater collection system and/or Water Resource Recovery Facility.
B 2.2.4 City as Exclusive Provider
The City will be the only provider of public wastewater treatment within the City (but on-site pretreatment of
wastewater to meet City Standards may be required).
Resolution No. 10893 (2018 Series)
EXHIBIT A
Chapter 8
Page 8-26
Figure 3 Capacity Constrained Areas
B 2.3 Programs
B 2.3.1 Expand capacity in the City’s collection system and Water Resource Recovery Facility in support of projected
wastewater flows.
B 2.3.2 Evaluate the potential for the wastewater flows of a proposed project to exceed the capacity of collection
and treatment systems.
B 2.3.3 The City will conduct periodic updates to its wastewater development impact fees.
Resolution No. 10893 (2018 Series)
EXHIBIT A
Water and Wastewater Element
Page 8-27
WASTEWATER TREATMENT
B 3.0 Background
The Water Resource Recovery Facility processes wastewater in accordance with standards set by the State's
Regional Water Quality Control Board (RWQCB). The RWQCB issues a permit to the City under the National
Pollutant Discharge Elimination System (NPDES), setting standards for the discharge of treated wastewater. The
standards are to protect beneficial uses of the receiving water (San Luis Obispo Creek) including recreation,
agricultural supply, and fish and wildlife habitat.
The Water Resource Recovery Facility removes solids, reduces the amount of nutrients, and eliminates bacteria in
the treated wastewater which is then discharged into San Luis Obispo Creek. Solids are separated and treated, to
create biosolids. Biosolids are beneficially reused as compost, and/or soil amendment. As described in Section A
7.0, the Water Resource Recovery Facility has been producing tertiary treated recycled water for delivery to
water customers in the City since 2006.
The design phase for the upgrade of the Water Resource Recovery Facility is underway with completion of
construction anticipated in 2022. The upgrade will enable the City to consider potable reuse, part of a One Water
concept, in the future.
B 3.1 Goals
B 3.1.1 Wastewater treatment that meets or exceeds regulatory requirements and ensures the protection of public
health and the environment.
B 3.1.2 Maximize recycled water production.
B 3.2 Policies
B 3.2.1 Treating Wastewater
The City will treat all wastewater in compliance with approved discharge permits.
B 3.2.2 Recycled Water Production
The City will produce high-quality, dependable recycled water, suitable for a wide range of uses.
B 3.2.3 Beneficial Use
The City will pursue treatment and disposal methods which provide for further beneficial use of wastewater
and biosolids.
B 3.3 Programs
B 3.3.1 Prepare and implement Water Resource Recovery Facility master plan consistent with regulatory
requirements.
B 3.3.2 Work cooperatively on regional water quality issues.
Resolution No. 10893 (2018 Series)
EXHIBIT A
Chapter 8
Page 8-28
COLLECTION SYSTEM
B 4.0 Background
The first sanitary sewers were built in San Luis Obispo in the late 1800s. Today portions of the collection system
are over 100 years old. It includes nine lift stations, approximately 135 miles of gravity sewer line and three miles
of force main. Approximately 2,900 manholes provide access to the collection system. The sewer lines are made
of a variety of materials, including terra cotta salt-glazed pipe, vitrified clay pipe (VCP), polyvinyl chloride (PVC),
and asbestos concrete.
The City’s wastewater collection system requires maintenance to ensure uninterrupted flows and minimize
sanitary sewer overflows. Area and preventive maintenance programs are regularly evaluated to ensure their
effectiveness. The City also utilizes video inspection to prioritize problem areas for replacement, maintenance,
assess overall mainline conditions, conduct inflow and infiltration evaluations, and assess new construction.
The City issues discharge permits to and conducts inspections of facilities that have the potential to discharge
pollutants in concentrations that could pose a threat to worker safety, the wastewater collection system, and/or
the Water Resource Recovery Facility. Through its Pretreatment Program, the City also implements programs to
target constituents of special concern.
Like most cities in California, San Luis Obispo has separate sewer and storm drain systems. This means each
system of pipes in the ground is designed to accommodate either sewer or stormwater flows. One set of pipes
takes sanitary waste to the Water Resource Recovery Facility while a second set carries stormwater runoff from
street drains directly into bioswales, detention basins, or creeks.
The City’s wastewater collection system and the Water Resource Recovery Facility have long experienced
problems associated with wet weather infiltration and inflow (I & I). Inflow is water that enters the collection
system at points of direct connection (non-soil) such as around manhole covers or through illegal connection of
roof drains, downspouts, or landscape drains. Infiltration is water that flows through the ground into the
collection system usually through cracks in public sewer mains and/or private sewer laterals (See Figure 4). I & I
overloads the collection system during heavy rains and can result in sanitary sewer overflows. During periods of
significant rain events, the Water Resource Recovery Facility can become hydraulically overwhelmed (as
mentioned previously, instantaneous peak flows exceeding 20 mgd are not uncommon during storm events)
increasing the chance of effluent violations and the release of partially treated wastewater to San Luis Obispo
Creek. Table 6 includes data on the highest average daily flows experienced at the Water Resource Recovery
Facility during rain events over a nine-year period.
Resolution No. 10893 (2018 Series)
EXHIBIT A
Water and Wastewater Element
Page 8-29
Table 6. Highest Average Daily Flows to the Water Resource Recovery Facility, 2006 to 2017
Average Daily Flows 1 Year
19.75 mgd 2006 (April)
7.24 mgd 2007(December)
9.83 mgd 2008 (January)
11.67 mgd 2009 (October)
13.51 mgd 2010 (December)
13.23 mgd 2011 (March
7.10 mgd 2012 (January)
5.17 mgd 2013 (January)
5.12 mgd 2014 (March)
5.24 mgd 2015 (February)
5.63 mgd 2016 (March)
9.00 mgd 2017 (February)
Note:
1. Instantaneous peak flows are higher.
2. August dry weather flow to the Water Resource Recovery Facility was 1.91 mgd in 2016 and 2.80 mgd in 2017.
Source: City of San Luis Obispo Utilities Department, 2018.
Figure 4 Inflow and Infiltration Illustrated
Resolution No. 10893 (2018 Series)
EXHIBIT A
Chapter 8
Page 8-30
B 4.1 Goal
Collect and convey all wastewater under safe and sanitary conditions to the Water Resource Recovery Facility.
B 4.2 Policies
B 4.2.1 Collection System Maintenance
The City will manage the collection system to ensure that the proper level of maintenance is provided and
that the flow in sanitary sewers does not exceed design capacity.
B 4.2.2 Infiltration and Inflow
The City will minimize stormwater and groundwater infiltration and inflow into the sewer system.
B 4.3 Programs
B 4.3.1 Investigate and carry out cost-effective methods for reducing infiltration and inflow into the wastewater
collection system.
B 4.3.2 Develop education and outreach materials to increase public awareness of problems associated with
excessive infiltration and inflow (I & I) into the wastewater collection system and the City’s efforts to reduce
I & I.
B 4.3.3 Support the retrofit of commercial and residential sewer laterals to reduce infiltration and inflow into the
wastewater collection system.
B 4.3.4 Update the Sewer System Management Plan to maintain its applicability.
B 4.3.5 Maintain, and revise as necessary, master plans for the extension of wastewater services to developing areas
of the City and to ensure orderly replacement of aged infrastructure.
B 4.3.6 Review development proposals to ensure new development does not adversely impact existing infrastructure
and that necessary infrastructure will be in place to support the development.
B 4.3.7 Provide a Pretreatment Program pursuant to the Clean Water Act to ensure that all discharge requirements
are met.
Resolution No. 10893 (2018 Series)
EXHIBIT A