WATER SUPPLY
ASSESSMENT
FOOTHILL CENTRAL
SPECIFIC PLAN UPDATE
October 2023
Prepared for:
City of Rialto
Prepared by:
6789 Quail Hill Pkwy, #421
Irvine, CA 92603
www. dopudjawells.com
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Table of Contents
Executive Summary ...................................................................................................................................... 6 1 Introduction ..................................................................................................................................................... 8
1.1 Background and Purpose .............................................................................................................. 8
1.2 Objective .................................................................................................................................................... 9
1.3 Report Organization ........................................................................................................................ 10 2 Description of Proposed Project ..................................................................................................... 11
2.1 Project Location and Description ........................................................................................... 11
2.2 Population Projection ................................................................................................................... 12
2.3 Existing Land Uses ........................................................................................................................... 14
2.4 Proposed Project Land Use Categories ........................................................................... 16 3 Existing and Projected Water Demand.................................................................................... 19
3.1 Water Demand Estimate Methodology............................................................................ 19
3.2 Historical Water Demands ........................................................................................................ 21
3.3 Estimated Project Water Demands ................................................................................... 24
3.4 Other Planned and Future Water Uses .......................................................................... 26
3.5 System Water Losses .................................................................................................................... 28 4 Regional Setting and Groundwater Management ......................................................... 29
4.1 Groundwater Management ..................................................................................................... 29
4.1 Role of the Regional Water Supplier .................................................................................. 30
4.2 Imported Water for Groundwater Recharge ............................................................... 31 5 Local Water Supplies .............................................................................................................................. 31
5.1 Groundwater ........................................................................................................................................ 32
5.2 Surface Water .................................................................................................................................... 43
5.3 Stormwater .......................................................................................................................................... 45
5.4 Recycled Water ................................................................................................................................ 45
5.1 Exchanges, Transfers, and Emergency Supply ........................................................... 46 6 Demand Management Measures ............................................................................................... 48
6.1 Water Use Efficiency and Conservation Programs ................................................. 48 7 Current and Projected Future Water Supply ...................................................................... 49
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7.1 Water Supply Reliability .............................................................................................................. 49
7.2 Water Year Characterization .................................................................................................... 51
7.3 Future Water Supply Projects ................................................................................................ 52
7.4 Single-Dry and Multiple-Dry Year Water Supplies .................................................. 52 8 Water Supply Adequacy and Reliability Evaluation ...................................................... 56
8.1 Normal Water Year ......................................................................................................................... 56
8.2 Single Dry Year .................................................................................................................................. 56
8.3 Multiple Dry Year ............................................................................................................................. 57 9 Conclusion ..................................................................................................................................................... 61
9.1 Verification and Approval Process ........................................................................................ 61
iii
Table of Tables
Table ES.1: Water Supply Adequacy and Reliability Evaluation under Normal Year Scenario, AFY ............................................................................................................... 7 Table ES.2: Water Supply Adequacy and Reliability Evaluation under Single and Multiple-Dry Year Scenario, AFY ................................................................................ 7 Table 1.1 Does the Proposed Project Meet the SB 610 Definition of a “Project” .. 9 Table 2.1: Project Water Service Purveyors ................................................................................. 12 Table 2.2: RWS Area Historic and Projected Populations ................................................. 12 Table 2.3: Existing Land Use Types: Foothill Specific Plan ............................................... 15 Table 2.4: Existing Land Use Types: Rialto Central Area Specific Plan1 ................... 15 Table 2.5: Existing Land Use Designations Compared to Proposed Project Land Use Designations ............................................................................................................... 17 Table 2.6: Breakdown of Proposed Land Use Types – Foothill Boulevard Specific Plan Area .................................................................................................................................. 17 Table 2.7: Breakdown of Proposed Land Use Types - Rialto Central Specific Plan Area .............................................................................................................................................. 18 Table 3.1: Water Demand Factors ...................................................................................................... 21 Table 3.2: Existing Water Demand and Projection for the Foothill Boulevard Specific Plan .......................................................................................................................... 23 Table 3.3: Existing Water Demand and Projection for the Rialto Central Specific Plan ............................................................................................................................................. 23 Table 3.4: Projected Water Demands for the Project ........................................................ 24 Table 3.5: Projected Net Increase in Project Water Demand ....................................... 24 Table 3.6 Planned and Future Water Uses Expected for the Rialto Water Service Area ............................................................................................................................................. 28 Table 5.1: Summary of Groundwater and Diversion Rights ............................................ 42 Table 5.1: City of Rialto Historical Water Supply by Source, AFY ................................. 47 Table 5.2: Fontana Water Company Historical Water Supply by Source, AFY . 47 Table 7.1: City of Rialto Projected Water Supply by Source, AFY ................................ 54 Table 7.2: Fontana Water Company Projected Water Supply by Source, AFY. 55 Table 8.1: Water Supply Adequacy and Reliability Evaluation under Normal Year Scenario, AFY ........................................................................................................................ 58 Table 8.2: Water Supply Adequacy and Reliability Evaluation under Single-Dry Year Scenario, AFY ............................................................................................................ 59 Table 8.3: Water Supply Adequacy and Reliability Evaluation under Multiple- Dry Year Scenario, AFY .................................................................................................. 60
iv
Table of Figures
Figure 2-1: Project Boundary and Water Purveyor Areas ................................................ 13 Figure 2-2: Existing Land Use Designations within Project Area ............................... 14 Figure 2-3: Proposed Land Use Types within Project Area ............................................. 18 Figure 3.1 Developments within City of Rialto ......................................................................... 27 Figure 5.1: Adjudicated Groundwater Basins serving the City of Rialto ................ 33
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Acronyms and Abbreviations
Acronyms and abbreviations used throughout this report include:
AFY Acre-Feet per Year
BTAC Basin Technical Advisory Committee
C Commercial
CEQA California Environmental Quality Act
City City of Rialto
C-MU Commercial-Mixed Use
C-P Commercial-Pedestrian
CUWCC California Urban Water Conservation Council
CWC California Water Code
DMU Downtown Mixed Use (1983 Rialto Central Area Specific Plan)
DMUZ Downtown Transit-Oriented Zone
du Dwelling Units
DWR Department of Water Resources
FMUZ Foothill Transit-Oriented Zone
FWC Fontana Water Company
gpd gallons per day
IEUA Inland Empire Utilities Agency
IRUWMP Integrated Regional Urban Water Management Plan
MAF Million Acre-Foot
MFR Multi-Family
mgd Million Gallons per Day
MWD Municipal Water District
P-F Public Facilities
Project Foothill Central Specific Plan Update
RBGC Rialto Basin Groundwater Council
R-HD Residential-High Density
R-MU Residential-Mixed Use
RWS Rialto Water Services
R-X Increased Density Residential
SB 221 Senate Bill 221
SB 610 Senate Bill 610
SFR Single Family Residential
SPU Foothill Central Specific Plan Update
SWP State Water Project
Veolia Veolia North America
WDF Water Demand Factors
WMP 2020 Water Master Plan
WSA Water Supply Assessment
WWTP Wastewater Treatment Plant
6 Executive Summary
This Water Supply Assessment (WSA) has been prepared for the City of Rialto by Dopudja and Wells Consulting in accordance with California Water Code (CWC) sections 10910 through 10915 for the Foothill Central Specific Plan Update (Project). The Project is a proposed redevelopment and merging of two distinct areas: the currently adopted Foothill Boulevard Specific Plan and the Rialto Central Specific Plan areas. Spanning a combined 482-acres, the Project site is located in the central portion of the City of Rialto in an existing mixed- use district. This WSA was developed to assist the City of Rialto in determining if water supplies are sufficient to meet the projected Project water demands, in addition to the City’s existing and other planned and anticipated future water uses. This was accomplished by:
o Identifying land use specifics and associated water demand factors for the proposed Foothill Central Specific Plan Update. o Determine water demand projections consistent with the methodology used in the City’s latest Water Master Plan. o Identifying all available water supply entitlements and water rights for the proposed Project
o Performing a detailed water supply assessment under normal, single- dry, and multiple-dry year conditions.
o Determine if the City will have sufficient water supply to meet the total projected water demand for the proposed Project, in addition to existing and planned future uses.
Water Demands
The anticipated Project water demands for the Buildout Scenario have been computed using the updated land uses and dwelling densities.
When considering the highest density demands for the redevelopment buildout, the projected water demand amounts to 2.18 million gallons per day (MGD), equivalent to approximately 2,446 acre-feet per year (AFY). This represents a 769 AFY net increase in water demand from the proposed Project when compared to the currently adopted Specific Plan areas under normal year conditions. Total water demand for the City’s water service area at buildout is as follows:
o Normal Year: 11,263 AFY
o Single-Dry Year: 12,390 AFY
o Multiple-Dry Year: 12,390 AFY
7 Water Supplies
The City has a diverse local water supply portfolio that relies on implementation of sustainable groundwater management practices.
The majority of water supply obtained by the City is from four different adjudicated groundwater basins. When considering water supply under normal, single-dry, and multiple-dry year conditions, the City anticipates no future changes to its existing water supply portfolio, the projected water supply for the City’s water service area at buildout (2045) is as follows:
o Normal Year: 13,356 AFY
o Single-Dry Year: 14,193 AFY
o Multiple-Dry Year: 14,193 AFY
Summary of Findings
The City’s water supplies are sufficient to meet the projected water demand, in addition to the City’s existing and other planned and anticipated future water uses. The City is anticipated to have a surplus of water supply over the planning period as shown in Tables ES.1 and ES.2. Additional information can be found in Section 8.
Table ES.1: Water Supply Adequacy and Reliability Evaluation under Normal Year Scenario, AFY
2020 2025 2030 2035 2040 2045
Water Supply Planning Projection
Total Water Supply 9,036 11,155 11,861 12,569 13,023 13,477 Water Demand Planning Projection
Total Water Demand 9,036 9,569 9,628 10,007 10,251 10,494 Net Increase in Project Water Demand
Net Increase in Demand 0 769 769 769 769 769
Water Supply Sufficiency
Potential Surplus / (Shortfall) 0 817 1,464 1,793 2,003 2,214
Table ES.2: Water Supply Adequacy and Reliability Evaluation under Single and Multiple-Dry Year Scenario, AFY
2020 2025 2030 2035 2040 2045
Water Supply Planning Projection
Total Water Supply 9,036 11,886 12,636 13,385 13,856 14,326 Water Demand Planning Projection
Total Water Demand 9,036 10,526 10,591 11,008 11,276 11,544 Net Increase in Project Water Demand
Net Increase in Demand 0 846 846 846 846 846
Water Supply Sufficiency
Potential Surplus / (Shortfall) 0 514 1,199 1,531 1,734 1,936
8 1 Introduction
This Water Supply Assessment (WSA) has been prepared for City of Rialto (City) by Dopudja and Wells Consulting in accordance with Water Code sections 10910 through 10915 for the Rialto Foothill Central Specific Plan Update (“Project”).
The Project aims to merge two distinct areas: the currently adopted Foothill Boulevard Specific Plan area, last updated in 2010, and the currently adopted Rialto Central Specific Plan area, last updated in 1983. The Project site is along Foothill Boulevard, a major arterial highway that runs east-west through Central Rialto and is bounded by Maple Avenue to the west and Pepper Avenue to the east. The northern boundary is loosely Etiwanda Avenue, and the Project is bounded by Merrill Avenue to the South. The overall land use is a mix of residential and neighborhood serving commercial spaces.
1.1 Background and Purpose
This report was prepared for the City of Rialto for the Foothill Central Specific Plan Update in accordance with California State Senate Bill 610 (SB 610) and Senate Bill 221 (SB 221), effective January 1, 2002. SB 610 and SB 221 aim to enhance the connection between land use decision-making and the accessibility of water supply to improve the communication and coordination among water suppliers and local land use agencies (cities and counties) when a significant project is proposed.
SB 610 amended California Water Codes (CWC) sections 10910-10915 to require a water supply assessment for any proposed project or development that is subject to California Environmental Quality Act (CEQA) documentation and that is a “project” defined by CWC section 10912(a). Concurrently, SB 221 mandates that approval from a city or county for specific residential subdivisions requires an affirmative written verification, confirming an adequate water supply.
Not every project bound by the requirements set by SB 610 could require the mandatory water verification set by SB 221. Similarly, not all projects subject to the requirements of SB 221 require a WSA to be included in the water environmental documentation as required by SB 610.
9 1.2 Objective
The objective of the WSA is to assess whether the combined projected water supplies held by the water agency, spanning regular, single-dry, and multiple- dry year conditions over a 20-year span, effectively meet the projected water demand associated with the proposed Project. This also extends to encompass the water agency's current, planned, and anticipated future uses, including, but not limited to, residential and commercial applications.
As previously described, to require a WSA, a project must satisfy one or more of the criteria outlined in accordance with CWC Section 10912(a). The marked checkboxes denote the specific requirements pertinent to the Project under consideration herein. As shown in Table 1.1 below, the proposed Project does meet the definition of a “Project” as specified in CWC Section 10912(a).
Table 1.1 Does the Proposed Project Meet the SB 610 Definition of a “Project”
“Project” as defined by 10912(a) Applicable to
Project
A proposed residential development of more than
500 dwelling units. Yes
A proposed shopping center or business
establishment employing more than 1,000 persons
or having more than 500,000 square feet of floor
space.
Yes
A proposed commercial office building employing
more than 1,000 persons or having more than
250,000 square feet of floor space.
No
A proposed hotel or motel, or both, having more than
500 rooms. No
A proposed industrial, manufacturing, or processing
plant, or industrial park planned to house more than
1,000 persons, occupying more than 40 acres of land,
or having more than 650,000 square feet of floor
area.
No
A mixed-use project that includes one or more of the
projects specified in this subdivision. Yes
A project that would demand an amount of water
equivalent to, or greater than, the amount of water
required by a 500 dwelling unit project.
Yes
10 1.3 Report Organization
This WSA is organized as follows:
o Section 2 provides an overview of the Project, including Project background, locations, and the proposed changes to land use type. o Section 3 details existing and projected water demands associated with the Project.
o Section 4 provides an overview of the proactive groundwater management measures undertaken by the regional water service provider, the City, and other agencies within the region. o Section 5 details existing and future water supplies for the City and made available to the Project.
o Section 6 outlines the water demand management measures currently implemented and planning for implementation by the City of Rialto. o Section 7 evaluates the availability of water supplies during single-dry and multiple-dry years.
o Section 8 provides a detailed assessment of whether the total projected water supplies are sufficient to meet the projected water demand associated with the proposed Project.
o Section 9 presents the conclusion and verification process for the WSA.
The information contained in this WSA is based on the city’s adopted General Plan, adopted Specific Plans for development opportunity areas, the 2020 Upper Santa Ana River Watershed Integrated Regional Urban Water Management Plan (IRUWMP) and the City of Rialto 2020 Water Master Plan (WMP). The WMP data has been updated with relevant water demand and supply reliability and other information provided by the California Department of Water Resources (DWR), City of Rialto, and the City where appropriate.
11 2 Description of Proposed Project
The following sections describe the Project, and provide an overview of the Project location, proposed land uses, and existing and projected water demands.
2.1 Project Location and Description
The Project is located in San Bernadino County within the City of Rialto. The Project location is between State Route 210 and Interstate 10 along Foothill Boulevard, a major arterial highway that runs east-west through Central Rialto.
The Project site is bound by Maple Avenue on the West and Pepper Avenue on the East with Merrill Avenue being the southernmost boundary and Etiwanda Avenue being the Northern most boundary. The Project comprises 482 acres within the City of Rialto.
Overall land use in the Project area is a mix of single family, multifamily, and high density residential and neighborhood-oriented commercial and public spaces. Approximately 25% of the Project area is currently vacant, consisting of various size lots.
The Project has set out a vision and strategy aimed at shaping the future growth and development of the City. The Project is designed to align with the City's General Plan. The Project comprises two areas: the Foothill Boulevard Specific Plan area, last updated in 2010, and the Central Rialto Specific Plan area, last updated in 1983. This Project aims to merge these two regions. and create a unified vision and identity for the Project area. The City’s General Plan identifies these two areas as the Foothill Boulevard and Downtown Rialto development opportunity areas per Figure 2.3.
The Project encompasses a set of policies intended to establish a network of pedestrian and bicycle pathways. These pathways are designed to facilitate pedestrian access to key transit routes such as the Metrolink, as well as commercial zones within the community. Additionally, the Project seeks to promote higher-density housing and the development of neighborhood centers that encourage a blend of employment and housing options. The overall aim is to offer housing and employment opportunities near transit hubs.
The City of Rialto’s water service area's water supply and distribution system is operated and maintained by RWS through a concession agreement with the
12 City, managed by contract with Veolia North America (Veolia). Although the City of Rialto maintains ownership of the water system, for the purposes of this report RWS will be referred to as the purveyor. While the primary water service provider for the Project area is RWS, a small portion of it is serviced by Fontana Water Company (refer to Table 2.1). Figure 2-1 illustrates the Rialto water service area, the boundary of the proposed Project, and the corresponding boundaries of each water purveyor.
Table 2.1: Project Water Service Purveyors 1
Existing Specific Plan
Designation Acres % Study
Area
Rialto Water Service Area 457 95%
Fontana Water Company 25 5%
Total 482 100%
Notes:
(1) Data obtained from GIS provided by City for 2020 WMP
2.2 Population Projection
Population projections were provided in the recently adopted Water Master Plan for the City of Rialto’s water service area and are based on information provided by the California DWR planning tool. Additional information regarding the data and methodologies used can be found in Rialto’s 2020 IRUWMP. Table 2.2 shows historical and projected future population growth within the City of Rialto’s water service area. In 2020, the estimated population was approximately 56,000 and was projected to be approximately 74,000 by 2045, with most of the growth for the City occurring over the next 10 to 15 years.
It should be noted that the unique condition of the City of Rialto’s water service area includes most of the nearly built-out portions of the city, with high development potential area being served by others. For purposes of this WSA, the following population estimates were used to assist with projecting intermediate future water demands by year from now to buildout.
Table 2.2: Historic and Projected Populations1
Year Population
2020 55,860
2025 59,669
2030 63,738
2035 68,084
2040 71,064
2045 74,175
Notes: (1) Data obtained from 2020 Rialto IRUWMP
13 Figure 2-1: Project Boundary and Water Purveyor Areas
14 2.3 Existing Land Uses
The Project merges two preexisting Specific Plans, the Rialto Central Specific Plan and the Foothill Boulevard Specific Plan. To provide a clearer picture of the current land uses, the land uses have been divided into each individual plan along with their corresponding Specific Plan designations, all of which are described below. Figure 2-2 illustrates the boundary and associated land use for the currently adopted Rialto Central and Foothill Boulevard Specific Plans.
Figure 2-2: Existing Land Use Designations within Project Area
The currently adopted Foothill Boulevard Specific Plan area is largely characterized by commercial and high density residential land uses promote mixed-use development and revitalization split into four zones. The four zones defined in the Foothill Boulevard Specific Plan promote mixed-use development and revitalization.
The Commercial-Pedestrian (C-P) district encourages pedestrian-oriented commercial development, allowing vertical mixed-use on three-acre parcels.
Similarly, the Commercial-Mixed Use (C-MU) district emphasizes multi-story development for a mix of commercial and residential uses. The Residential- Mixed Use (R-MU) district focuses on higher-density residential, permitting vertical mixed-use and 'live-work' units. Lastly, the Residential-High Density (R- HD) district aims to increase residential units along Foothill Boulevard, allowing various housing types and 'live-work' units.
15 Table 2.3: Existing Land Use Types: Foothill Specific Plan 1 Existing Specific
Plan Designation
Area
(Acres)
Occupied
Area
(Acres)
% Vacant
Commercial
Pedestrian (C-P) 155 119 23%
Commercial
Mixed Use (C-MU) 21 9 59%
Residential Mixed
Use (R-MU) 36 17 53%
Residential (R-
HD) 46 20 56%
Total 258 169 36%
Notes:
(1) Data obtained from City GIS
The Central Rialto Specific Plan zone is characterized by a diverse range of land uses described below. The Single-Family Residential (Residential 12) zone focuses on enhancing single-family structure design. The Multiple-Family Residential (Residential 21) zone aims to diversify housing types. The Increased Density (Residential 35) zone encourages affordable housing development and higher allowable densities. The Office zone accommodates offices and professional services, with a focus on compatibility with nearby residential areas. The Downtown Mixed-Use zone supports commercial, residential, and civic uses to bolster the economic vitality of the specific plan area.
Table 2.4: Existing Land Use Types: Rialto Central Area Specific Plan1 Existing Specific Plan
Designation Area (Acres) Occupied
Area (Acres) % Vacant
Downtown Mixed-Use 59 48 19%
Office 14 12 11%
Residential 12 67 66 1%
Residential 21 47 34 29%
Residential 35 18 18 1%
School Facility 19 19 0%
Total 224 196 12%
Notes:
(1) Data obtained from GIS provided by the City for Project
16 2.4 Proposed Project Land Use Categories
The following are the proposed Project land use categories:
o Single Family Residential (SFR): Low-density residential area in downtown Rialto for single-family homes, separate from multi-family and non-residential uses, to maintain a family-friendly environment. o Multi-Family Residential (MFR): Medium-density residential zone promoting walkable neighborhoods with various housing types like apartments, townhomes, and duplexes.
o Increased Density Residential (R-X): Encourages housing development through higher allowable density and flexible lot development standards, featuring medium- to high-density housing types. o Foothill Transit-Oriented Zone (FMUZ): Encourages retail on the ground floor and office or residential spaces above, near future Bus Rapid Transit stops along Foothill Boulevard.
o Downtown Transit-Oriented Zone (DMUZ): Focuses on a walkable mixed-use central area with ground-floor retail, higher-intensity offices, and residential spaces, particularly near the Rialto Metrolink Station. o Commercial (C): Supports retail establishments with on-site parking, allowing offices on higher floors and residential development under specific criteria.
o Public Facilities (PF): Designation for public and community-serving facilities like Civic Center, government buildings, schools, and recreational centers.
Table 2.5 below details how the existing land use designations transition into the new land use categories defined by the Project.
Tables 2.6 and 2.7 offer a detailed breakdown of the new land use designations within the area, outlining the total land area, occupied land area, and percent land area that is vacant with the new designations from the proposed Project.
Table 2.6 presents the new designations that are within the currently adopted Foothill Boulevard Specific Plan area and Table 2.7 presents the new designations that are within the currently adopted Rialto Central Specific Plan.
17 Table 2.5: Existing Land Use Designations Compared to Proposed Project Land Use Designations1
Original
Former
Specifi
c Plan
Acres
FMUZ
2 Acres
DMUZ
3 Acres
Commercial
2,3
Acres
SFR 3
Acres
MFR 3
Acres
R-X 3
Acres
P-F 3
Commercial
Pedestrian
(C-P)
Foothill 64 0 91 0 0 0 0
Commercial
Mixed Use
(C-MU)
Foothill 13 0 8 0 0 0 0
Residential
Mixed Use
(R-MU)
Foothill 36 0 0 0 0 0 0
Residential
(R-HD) Foothill 46 0 0 0 0 0 0
Downtown
Mixed-Use
Rialto
Central 0 32 16 0 1 0 10
Office Rialto
Central 0 14 0 0 0 0 0
Residential
12 Rialto
Central 0 0 0 14 52 0 0
Residential
21 Rialto
Central 0 14 7 0 20 4 2
Residential
35 Rialto
Central 0 0 0 0 0 18 0
School
Facility
Rialto
Central 0 0 0 0 0 0 19
Notes:
(1) Data obtained from GIS provided by the City for Project (2) Refer to Table 2.8 for details regarding occupied areas within each land use designation.
Table 2.6: Breakdown of Proposed Land Use Types – Foothill Boulevard Specific Plan Area
Proposed Specific
Plan Designation Acres % Vacant Occupied
Acres
FMUZ 159 43% 91
Commercial (C) 99 25% 74
Total 258 36% 165
Notes:
(1) Data obtained from GIS provided by the City for Project
18 Table 2.7: Breakdown of Proposed Land Use Types - Rialto Central Specific Plan Area1
Proposed
Specific Plan
Designation
Area (Acres)
Occupied
Area
(Acres)
% Vacant
DMUZ 60 43 28%
P-F 31 30 2%
Commercial (C) 22 21 8%
SFR 14 14 0%
MFR 74 66 10%
R-X 23 21 5%
Total 224 196 12%
Notes:
(1) Data obtained from GIS provided by the City for Project
Figure 2.3 illustrates where the new land use designations are within the Project area.
Figure 2-3: Proposed Land Use Types within Project Area
19 3 Existing and Projected Water Demand
This section summarizes the projected water demands for the proposed Project and overviews other planned and future water uses within the Rialto water service area. The WSA is based on full buildout conditions to estimate the net increase in water demand from the proposed Project. The WMP provided existing water demand and projected buildout water demand for the entire City of Rialto’s water service area. Water demands for existing developments in the SPU area were included in the WMP and based on WDFs applied to each corresponding land use identified in the City’s adopted General Plan (including the Specific Plan land use designations from the Foothill Boulevard and Rialto Central plans).
Projected water demands for the Project have been estimated based on the water demand factors (WDF) established in the latest WMP. This section offers a comprehensive description of the current water demands and outlines the methodology employed to project future water demand associated with the SPU, including:
o Land use and demographic projections- Overview of current and projected water demand with present land use zoning and how land use zone changes are expected to change demand for water in the future. o Demand forecast- Provides the methodology used to forecast demand to year 2045 based on actual 2020 water demands.
3.1 Water Demand Estimate Methodology
According to 2020 data provided by the City, the study area is largely built-out, with 75% of the land occupied, leaving only 25% of the land vacant. It is expected that new developments and growth will primarily result from increased housing density and intensified land use or redevelopment of existing land.
Existing Study Area and Growth Expectations
Due to the mixed land use categorization of the Project area, where parcels often combine residential and commercial elements, water use categorization was based on specific plan zoning codes, including the four (4) zones identified from the currently adopted Foothill Boulevard Specific Plan and six (6) identified from the Rialto Central, or Downtown Specific Plan, were used for this purpose. Refer to Table 2.3 and 2.4 for summary of the specific plan zoning codes.
20 Historical Water Usage and Selection of Water Demand Factors Historical water demand projections for the Project area were determined by applying WDFs established from the WMP to each proposed land use. The choice to utilize the WMP's demand values, rather than those from the IRUWMP, was driven by the WMP's methodology for calculating WDFs, which relied on actual historic billing data projected forward, rather than an estimated count of metered connections projected across the region.
WDFs were applied to develop a conservative, yet realistic estimate of water demand. To determine existing water demand, the following categories were exclusively classified as commercial:
o Commercial-Pedestrian (C-P)
o Commercial-Mixed Use (C-MU)
o Residential- Mixed Use (R-MU)
o Downtown Mixed-Use (DMU)
This approach most closely accounts for the current usage and therefore current demand for these categories. However, when considering the area's build-out potential, which includes vacant land, calculations for these categories combined both residential and non-residential demand to account for the desired mixed use of these parcels. This approach accounts for the expectation that increased density and the integration of work and recreational spaces would play a role in the conceptualization of future land use.
Calculation Methodology for Residential Zones
Following the WMP methodology, residential WDFs were calculated on a per capita basis. For this WSA, the per capita WDFs were converted to a per dwelling usage using the existing dwelling unit data and land area from the 2020 WMP GIS data as follows:
o WMP lists 96 gpd/capita as the residential demand factor. o This residential demand factor was multiplied by population given in the GIS provided by the City to arrive at demand.
o The resulting demand was divided by the number of units to arrive at unit demand factors.
All other demand factors, consistent with the WMP, were calculated on an area-specific basis.
21 Water Demand Factor Summary
The following values were used in the calculation of water demand, in gallons per day (gpd) per acre and in acre-feet per year (AFY) per acre, for the study area:
Table 3.1: Water Demand Factors 1
Land Use Type Water Demand
Factor
Water Demand
Factor
Commercial 1500 gpd/acre 1.68 afy/acre
Government/Institutional 2050 gpd/acre 2.30 afy/acre
Residential 353 gpd/du 0.40 afy/du
1 Data obtained from 2020 WMP
3.2 Historical Water Demands
Tables 3.2 and 3.3 summarize the anticipated buildout water demand for the currently adopted Foothill Boulevard Specific Plan and Rialto Central Specific Plan based on the methodology presented in Section 3.1.
For residential water demand calculations, the existing density (dwelling units per acre) served as a fundamental factor. To establish the existing density within the Project area, data from the GIS employed in the WMP was utilized.
Specifically, the number of existing dwelling units was extracted from the GIS dataset and then divided by the number of occupied acres, which was also sourced from the GIS. This calculation yielded the existing density in units of dwelling units per acre.
For residential water demand calculations, existing density (dwelling units per acre) in the Project area was crucial. This was determined using GIS data:
o Extracted existing dwelling units from GIS dataset
o Divided by the number of occupied acres from GIS
o Result: Existing density in dwelling units per acre, a fundamental factor for the calculations."
To calculate the EWD for land uses that included a residential component, the number of existing acres (as indicated by the GIS parcel data provided for the WMP) was multiplied by the existing density, and then further adjusted by the water demand factor to derive the existing water demand. A realistic calculation of existing density was used as opposed to using the maximum density figures. For build-out projections, vacant lots within strictly residential zones were assumed to reach their maximum density potential. However, in mixed-use areas, a different approach was taken. Here, it was assumed that
22 existing residential density would be multiplied by the ratio of max density divided by existing density to account for the potential of the corresponding land use areas to be developed at the maximum density allowed per acre.
23 Table 3.2: Existing Water Demand and Projection for the Foothill Boulevard Specific Plan 1 Existing Specific
Plan
Designation
Area
(Acres)
Vacant
Area (Acres)
Existing Water
Demand Factor
Type
Existing
Water
Demand
(mgd)
Buildout Water
Demand Factor
Type
Building out
Water
Demand
(mgd)
Water
Use
Growth
(AFY)
Commercial
Pedestrian (C-P) 155 36 Commercial 0.179 Commercial
+ Residential 0.235 63
Commercial
Mixed Use (C-
MU)
21 12 Commercial 0.013 Commercial
+ Residential 0.041 32
Residential
Mixed Use (R-
MU)
36 19 Commercial 0.026 Commercial
+ Residential 0.074 54
Residential (R-
HD) 46 26 Residential 0.107 Residential 0.423 354
Total 258 93 N/A 0.324 N/A 0.774 504
Notes: (1) Data obtained from GIS provided by the City for Project
Table 3.3: Existing Water Demand and Projection for the Rialto Central Specific Plan 1 Existing
Specific Plan
Designation
Area
(Acres)
Vacant Area
(Acres)
Existing Water
Demand Factor
Existing
Water
Demand
(mgd)
Buildout Water
Demand Factor
Building out
Water
Demand
(mgd)
Water
Use
Growth
(AFY)
Downtown
Mixed-Use 59 11 Commercial 0.072 Commercial
+ Residential 0.124 28
Office 14 2 Commercial 0.018 Commercial 0.021 3
Residential 12 67 1 Residential 0.290 Residential 0.294 4 Residential 21 47 13 Residential 0.076 Residential 0.176 112 Residential 35 18 0 Residential 0.097 Residential 0.098 1 School Facility 19 0 Government 0.039 Government 0.039 0 Total 224 27 N/A 0.591 N/A 0.724 148
Notes: (1) Data obtained from GIS provided by the City for Project
24 3.3 Estimated Project Water Demands
This section summarizes the proposed WDFs assigned to each of the land use designations for the Project.
Table 3.4 illustrates buildout water demand for the proposed land use types. As shown in Table 3.5, based on the projected water demand at buildout conditions, the Project is estimated to have a 769 AFY net increase in water demand when compared to the currently adopted Specific Plans (Tables 3.2 and 3.3).
Table 3.4: Projected Water Demands for the Project
Existing
Specific Plan
Designation
Total
Area
(Acres)
Vacant
Area
(Acres)
Existing Water
Demand Factor
Existing Water
Demand (mgd)
Buildout Water
Demand Factor
Buildout Water
Demand (mgd)
Water Use
Growth,
AFY
FMUZ 159 68 Commercial 0.137 Commercial
+ Residential 1.04 1,014
DMUZ 60 17 Commercial 0.065 Commercial
+ Residential 0.366 338
P-F 31 1 Government 0.062 Government 0.063 1
Commercial (C) 121 27 Commercial 0.142 Commercial 0.184 48 SFR 14 0 Residential 0.025 Residential 0.025 0
MFR 74 7 Residential 0.331 Residential 0.388 63
R-X 23 1 Residential 0.107 Residential 0.116 9
Total 482 121 N/A 0.869 N/A 2.184 1,473
Notes: (1) Data obtained from GIS provided by the City for Project
Table 3.5: Projected Net Increase in Project Water Demand Specific Plan
Designation
Buildout Water
Demand (mgd)
Buildout Water
Demand (AFY)
Currently Adopted
Plans 1 1.497 1,678
Foothill Central SPU 2.184 2,447
Total Net Increase 0.687 769
Notes (1) Includes Foothill Boulevard and Rialto Central Specific Plans.
25 26
3.4 Other Planned and Future Water Uses
All anticipated developments in the near term were identified to estimate water demand for the years 2025 and 2030. Developments were identified in coordination with the City as either complete, in construction, or as having commenced pre-development planning services. Water demand for each development site was estimated based on the methodology presented in Section 3.1. Figure 3.1 illustrates the location of each project site and details regarding each development are summarized in Table 3.5.
Projects Completed or Approved since 2020
The City has identified ten development sites that have been completed or are currently under construction, which resulted in new demand for the Rialto water service area since 2020. Demand associated with these developments was included in the 2025 water demand projection.
Anticipated Future Water Uses Post 2025
Based on the information provided by the City’s planning division, 9 project sites were identified as anticipated development projects which have commenced pre-development and planning activities but have not received jurisdictional approval. Water demand associated with these project sites were included in the 2030 water demand projection.
27 Figure 3.1 Developments within City of Rialto
28 Table 3.6 Planned and Future Water Uses Expected for the Rialto Water Service Area 1, 2 Project
Site
Within
Project
Area?
Status
Water
Demand
Factor
Land
Area
(acres)
Additional
Water Demand
(mgd)
Additional
Water Demand
(AFY)
11 No Complete Commercial 54 0.082 91
21 No Complete Commercial 17 0.026 29
31 No Complete Commercial 31 0.047 52
41 Yes Complete Residential 14 0.178 200
51 Yes Complete Residential 1 0.010 11
61 Yes Complete Residential 5 0.035 40
71 No Complete Commercial 8 0.012 13
81 No In Progress Commercial 13 0.020 22
91 No In Progress Commercial 18 0.027 31
101 No Complete Commercial 5 0.007 8
112 No In Progress Commercial 4 03 03
122 No In Progress Commercial 3 0.005 5
132 No In Progress Commercial 5 03 03
142 Yes In Progress Residential 2 0.012 14
152 Yes In Progress Residential 5 0.024 27
162, 4 No In Progress Commercial 3 0.004 5
172, 4 No In Progress Commercial 4 0.007 7
182, 4 No In Progress Commercial 16 0.023 26
192 No In Progress Commercial 2 0.003 3
Total 210 0.522 584
Note:
(1) Projects verified by City of Rialto since 2020
(2) Projects listed as current at https://www.yourrialto.com/314/Current-Projects (3) No additional water demand produced from redevelopment as the development is not changing in type or area.
(4) Project area is outside Rialto water service area
3.5 System Water Losses
Distribution system losses are part of every water distribution system, consisting of water loss from leaks, unmetered water consumptions, theft, and meter inaccuracies. The City monitors its water loss and prepares an annual water audit to estimate the volume of water loss. Based on the results of the last five years, average water loss was estimated to be approximately 6.9- percent. To estimate expected water loss under for this WSA, 6.9-percent water loss was assumed as part of the water supply assessment results presented in Section 8.
29 4 Regional Setting and Groundwater
Management
The City and Fontana Water Company are located within the Upper Santa Ana River watershed, an area with unique hydrological characteristics, significant groundwater storage capacity, and an area with long-standing integrated water management efforts undertaken by agencies located within the watershed. Agencies within the region coordinate and collectively manage the groundwater basins by managing pumping and securing imported water deliveries for groundwater recharge. This section will overview the roles of the regional water service providers and the proactive groundwater management measures undertaken by the City, Fontana Water Company, and other water service providers in the region.
4.1 Groundwater Management
Among the various water management efforts undertaken within the region, the City and Fontana Water Company are active members of the following planning committees promoting sustainable groundwater management practices:
o City of Rialto is a member of the San Bernardino Basin Groundwater Council to assist with actively managing, restoring, and maintaining local groundwater basin levels.
o City of Rialto and Fontana Water Company are both members of the Rialto Basin Groundwater Council to optimally manage the basin and protect from overdraft and mitigate low groundwater levels.
o City of Rialto is a member of the Basin Technical Advisory Committee to assist with implementing management strategies included in the 2007 Upper Santa Aan River Watershed Integrated Regional Water Management Plan.
Regional water management actions have led to the development and implementation of active management strategies to ensure a reliable water supply future for cities and communities within Riverside and San Bernardino Counties. It is estimated that the total usable storage in the Bunker Hill Basin, Rialto-Colton Basin and the North Riverside Basin is approximately 7.6 MAF and the Chino Basin has approximately 6 MAF of storage (DWR Bulletin 118 Basin Descriptions).
30 4.1 Role of the Regional Water Supplier
In the 1960s, the over-commitment of water in the Santa Ana River watershed led to lawsuits between water users in the upper and lower watersheds regarding the use of both surface flows and groundwater. The lawsuits culminated into the Chino Judgement, Orange County Judgement and the Western San Bernardino Judgment. Under the terms of the settlements, the court appointed Watermasters responsible for providing a specific amount of Santa Ana River base flow to Orange County and maintaining the safe yield in the Chino and San Bernardino Basin Areas.
The judgments resolved the major water rights issues that had prevented the development of long-term, region-wide water supply plans and established specific objectives for the management of the groundwater basins. It should be noted that majority of the water supply for the proposed Project comes from San Bernardino Basin which is managed by the Western San Bernardino Judgement. Under the Western San Bernardino Judgement, the San Bernardino Valley MWD leads basin management activities for the basin and is one of two regional water agencies in the area. The following section overviews the San Bernardino Valley MWD and their role in basin management.
San Bernardino Valley MWD
San Bernardino Valley MWD is the regional water provider for the City and also leads basin management efforts for the San Bernardino Basin.
The San Bernardino Valley MWD covers about 353 square miles in southwestern San Bernardino County, about 60 miles east of Los Angeles, and has a population of about 714,000. It spans the eastern two- thirds of the San Bernardino Valley, the Crafton Hills, and a portion of the Yucaipa Valley and includes the cities and communities of San Bernardino, Colton, Loma Linda, Redlands, Rialto, Bloomington, Highland, East Highland, Mentone, Grand Terrace, and Yucaipa.
San Bernardino Valley MWD receives State Water Project (SWP) water at the Devil Canyon Power Plant Afterbay (near California State University San Bernardino). Water is transported 17 miles eastward to various spreading grounds, agricultural, and wholesale domestic delivery points in the San Bernardino Basin; and transported westward for direct delivery and recharge in the Colton-Rialto basin. Supplemental water purchased for groundwater recharge is either delivered directly to groundwater spreading basins for recharge, or taken in-lieu of pumping groundwater, both actions resulting in an increase in groundwater
31 available for future use. The City actively participates in basin management efforts and coordinates supplemental imported water purchases with San Bernardino Valley MWD as necessary. Basin management activities are currently administered through the following planning committees:
o San Bernardino Basin Groundwater
o Rialto Basin Groundwater Council
o Basin Technical Advisory Committee
4.2 Imported Water for Groundwater Recharge
The City does not currently purchase imported water for direct retail use but does purchase imported water from San Bernardino Valley MWD for groundwater storage and basin management. In 1991, the City executed an agreement with San Bernardino Valley MWD to purchase up to 2,500 AFY of supplemental water for groundwater recharge for 20 years, with the option of two 10-year extensions.
Purchases made by the City for supplemental water varies yearly and is dependent on groundwater conditions and availability of imported water from San Bernardino Valley MWD. Additional information regarding availability and the reliability of imported water can be found in the City of Rialto’s 2020 IRUWMP, Part 1, Chapter 3.
5 Local Water Supplies
The City has a diverse portfolio of local water supplies that relies on sustainable groundwater management practices for future water supply reliability. This is accomplished by providing supplemental water for groundwater recharge whenever cumulative groundwater extractions exceed predefined groundwater operating yields, when groundwater levels are lower than specified groundwater elevations at key wells, or when surplus imported water is available for purchase from the regional wholesale agency for replenishing groundwater basins. Water supplies for the City are obtained from the following sources, with most of the City’s water supply obtained from groundwater sources:
o Groundwater from four different adjudicated groundwater basins: The Rialto-Colton Basin, Lytle Creek Basin, North Riverside Basin, and the Bunker Hill Basin. The City also purchases additional groundwater from
32 the Bunker Hill Basin and delivered through a shared delivery system called the Baseline Feeder.
o Surface water from canyon surface flows on the east side of the San Gabriel Mountains, including the North Fork Lytle Creek, Middle Fork Lytle Creek, and South Fork Lytle Creek. These sources of supply are treated at the Oliver P. Roemer Water Filtration Plant which is owned and operated by West Valley Water District. The City has acquired and owns 25% of the capacity of the plant.
o Emergency and stand-by agreements with the City of San Bernardino, Riverside-Highland Water Company, West Valley Water District, and Fontana Water Company for unforeseen catastrophic and emergency events.
o Purchased or Imported Water is currently not a source of supply for the City, but the city does actively participate in regional efforts and purchases imported water from the State Water Project via San Bernardino Valley Municipal Water District (San Bernardino Valley MWD) for groundwater recharge and basin management activities.
The Fontana Water Company water supplies are obtained from sources similar to the City of Rialto. Fontana Water Company receives water supply from the following sources:
o Surface water from canyon surface flows on the east side of the San Gabriel Mountains, including the North Fork Lytle Creek, Middle Fork Lytle Creek, and South Fork Lytle Creek. These sources of supply are treated at the Summit Surface Water Treatment Plant that is owned and operated by Fontana Water Company.
o Imported Water purchased from the Inland Empire Utilities Agency (IEUA) and San Bernardino Valley MWD and treated at the Summit Surface Water Treatment Plant.
o Recycled water for irrigation purchased from IEUA
o Groundwater from three different adjudicated groundwater basins: The Rialto-Colton Basin, Lytle Creek Basin, and the Chino Basin.
5.1 Groundwater
The majority of Rialto’s water supply consists of groundwater, and the City will continue to rely on groundwater as its preferred source of supply in future years. The City and Fontana Water Company produce groundwater from five different adjudicated groundwater basins as depicted in Figure 5.1. Each basin with unique hydrological characteristics and significant groundwater storage capacity. It should be noted that the figure identifies the San Bernardino Basin, which encompasses the Bunker Hill and Lytle Creek Subbasins.
33 Regional water management actions taken by the City, Fontana Water Company, and surrounding agencies within the watershed have led to comprehensive and robust management policies to ensure a reliable water supply future for cities and communities within Riverside and San Bernardino Counties. This section provides an overview of each groundwater basin utilized by the City and Fontana Water Company.
Figure 5.1: Adjudicated Groundwater Basins serving the City of Rialto
Chino Basin
The Chino Basin (Basin Number 8-2.01) is a subbasin of the Upper Santa Ana Valley Basin (Basin Number 8-2) contained within the DWR’s South Coast Hydrologic Region. The Chino Basin is in San Bernardino County and is one of the largest groundwater basins in southern California, containing approximately 5 million AF of water in storage, with an
34 additional 1 million AF of unused storage capacity. The groundwater management plan for the Chino Basin is contained within the Chino Basin Municipal Water District, vs. City of Chino, et al., 1978 (Chino Basin Judgement). The Chino Basin is an adjudicated basin. According to the DWR Bulletin 118 (California’s groundwater), DWR has not identified the Chino Basin as one of the basins being in “critical condition of overdraft”.
The Chino Basin contains 235 square miles of the upper Santa Ana River watershed and is bounded by the Rialto-Colton, Chino, San Jose, and Cucamonga faults, and by the Puente Hills and the San Gabriel Mountains.
In 1975, several Chino Basin produces filed suit in California State Court for San Bernardino County to settle the problem of allocating water rights in the Chino Basin. In 1978, the Court authorized the Chino Basin Judgement adjudicating water rights in the Chino Basin and establishing the Chino Basin Watermaster. The Chino Basin Judgement adjudicated all water rights in Chino Basin and contains a physical solution to meet the requirements of water users having rights in or dependent upon the Chino Basin. The Judgment also appointed the Watermaster to account for and implement the management of the Chino Basin. The Judgment declared that the initial operating safe yield of the Chino Basin is 145,000 AFY. The Basin is managed through implementation of the Chino Optimum Basin Management Plan. Per the Judgment, Fontana Water Company groundwater right is approximately 11.7 -percent of operating safe yield. Groundwater production from the Chino Basin from 2016 to 2020 averaged approximately 11,800 AFY (2020 UWMP). Groundwater extractions above their allocation of operating safe yield must be replenished by purchasing imported water through a program with the Chino Basin Watermaster.
In 2020, the Chino Basin Watermaster and parties reset the Safe Yield of the basin to 131,000 AFY. The Safe Yield is defined in the Chino Basin Judgment as “the long-term average annual quantity of ground water (excluding replenishment of stored water but including return flow to the Basin from use of replenishment or stored water) which can be produced from the Chino Basin under conditions of a particular year without causing an undesirable result.” The allocation of the Safe Yield of the Chino Basin includes three separate Pools: the “Overlying Agricultural Pool (82,800 AFY)”, the “Overlying Non-Agricultural Pool (7,366 AFY)”, and the “Appropriative Pool (40,834 AFY)”. Fontana Water Company currently owns appropriative rights based on a 0.002 percent
35 share of the ‘Operating Safe Yield’. Fontana Union Water Company, of which Fontana Water Company is a principal shareholder (over 40 percent of outstanding stock), currently owns appropriative rights based on an 11.66 percent share of the ‘Operating Safe Yield’.
Appropriators who are parties to the Chino Basin Judgment, such as Fontana Water Company, are authorized to extract groundwater in excess of the allocated quantities. However, appropriators pay an assessment for such extractions to the Chino Basin Watermaster. The assessments are used to purchase untreated imported water to recharge the Chino Basin. Water to replenish the Chino Basin is purchased from Metropolitan Water District by IEUA in cooperation with the Chino Basin Watermaster. Future additional supplemental sources of replenishment water are expected to come from recycled water and from increased recharge of storm water.
The Chino Basin is a main source of water supply for the Fontana Water Company. Historical groundwater production from the Chino Basin is shown in Table 5.2. Projected future production from the Chino Basin in normal, single-dry, and multiple-dry years is shown in Table 7.2. As stated in the Fontana Water Company 2020 Urban Water Management Plan, Section 7 Water Service Reliability and Drought Risk Assessment, groundwater supply from Chino Basin is assumed to provide 100- percent of the remaining water supply during a single-dry and multiple- dry year condition.
Bunker Hill Basin
The Bunker Hill Basin (Basin Number 8-2.06) is a subbasin of the Upper Santa Ana Valley Basin (Basin Number 8-2) contained within the DWR’s South Coast Hydrologic Region. The Bunker Hill Basin is in San Bernardino County and is one of the largest groundwater basins in southern California, containing approximately 5.97 million AF of usable storage and includes several principal recharge areas where supplemental water is delivered for groundwater recharge.
Supplemental water consists of captured stormwater or purchased imported water from the State Water Project. The Bunker Hill Basin contains 120 square miles of the upper Santa Ana River watershed and consists of the alluvial materials that underlie the San Bernardino Valley.
This subbasin is bounded by contact with consolidated rocks of the San Gabriel Mountains, San Bernardino Mountains, and Crafton Hills, and by several faults. The southern boundary is the Banning fault, the east boundary is the Redlands fault, the San Andreas fault is roughly the
36 northern boundary, the Glen Helen fault abuts the northwest boundary, and the southwest boundary is the San Jacinto fault. The groundwater management plan for the Bunker Hill Basin is contained within the Western Municipal Water District of Riverside County, et al. vs. East San Bernardino County Water District, et al., 1969. (Western Judgement). In addition, San Bernardino Valley MWD initiated the Basin Technical Advisory Committee (BTAC), made up of water agency staff and regional stakeholders to implement regional water management plans and strategies based on past planning efforts and underlying regional agreements and judgements. The Bunker Hill Basin is an adjudicated basin and included as part of the San Bernardino Basin as described in the Western Judgement. According to the DWR Bulletin 118 (California’s Groundwater), DWR has not identified the Bunker Hill Basin as one of the basins being in “critical condition of overdraft”.
The Western Judgement calculated the natural safe yield of the San Bernardino Basin to be 232,100 AFY, including all groundwater extractions and surface water diversions. A copy of the Western Judgement is provided in Appendix X. Surface water within the San Bernardino Basin is diverted from Mill Creek, Lytle Creek, and the Santa Ana River. The Western Judgement allocates the natural safe yield of the basin into the following two categories:
o Plaintiff Parties: include the City of Riverside, Riverside Highland Water Company, Meeks and Daley Water Company, and Regets of the University of California. Plaintiffs received 27.95 percent of natural safe yield, or 64,862 AFY. Plaintiffs cannot exceed their allocation of natural safe yield unless they participate in projects defined as “New Conservation”, projects that would increase the amount of water (stormwater capture, imported water, other) available for groundwater recharge.
o Non-Plaintiff Parties: include the City of Rialto and agencies within San Bernardino County. Non-Plaintiffs receive 72.05 percent of the natural safe yield, or 167,238 AFY. Non-Plaintiffs are allowed to exceed their allocation of safe yield as long as they purchase and recharge a like amount of supplemental imported water to the San Bernardino Basin for groundwater recharge.
The Western Judgement describes annual accounting procedures for both Plaintiff and Non-Plaintiffs. These reports are published annually and are required by the Western Judgement. Based on the 2022 Western-San Bernardino Annual Watermaster Report, the Non-Plaintiffs
37 have XXX AFY of net credit accumulated in the San Bernardino Basin and are, therefore, not required to recharge. Although there is no recharge required under the Western Judgement, the Non-Plaintiffs have continued to recharge the San Bernardino Basin.
Baseline Feeder - Bunker Hill Basin
In 1991 the City entered into a multi-party agreement with San Bernardino Valley MWD, West Valley Water District, and Riverside Highland Water Company to construct the Baseline Feeder pipeline. The Baseline Feeder is a 48-inch transmission pipeline and the City owns 33- percent of the pipeline capacity from Meridian Avenue and Baseline Road to Cactus Avenue and Baseline Road. Following the 1991 multi- party agreement, the City also entered into agreement with West Valley Water District to jointly construct and operate a 1.0 million gallon reservoir and booster pump station to convey groundwater pumped from the Bunker Hill Basin into the Baseline Feeder. The City owns 33- percent of the reservoir and associated booster pump station. City Well #4A produces groundwater from Bunker Hill Basin and pumps directly into the reservoir and is then boosted into the Baseline Feeder for delivery to the City. All water delivered through the Baseline Feeder is Bunker Hill Basin groundwater and is included in the total Bunker Hill Basin production for the purpose of this document.
In 2012, the parties restated and amended their agreement to include additional capital facilities. The amended agreement allowed for the City to construct two new groundwater wells located in the Bunker Hill Basin and have rights to access up to 2,500 AFY at the established operational costs for 20 years. A copy of the Baseline Feeder agreements is provided in Appendix X.
The Bunker Hill Basin is the main source of water supply for the City. The City’s historical groundwater production from the Bunker Hill Basin is shown in Table 5.1. Projected future production from the Bunker Hill Basin in normal, single-dry, and multiple-dry years is shown in Table 7.1.
Rialto-Colton Basin
The Rialto-Colton Basin (Basin No. 8-2.04) is a subbasin of the Upper Santa Ana Valley Basin (Basin Number 8-2) contained within the DWR’s South Coast Hydrologic Region. The Rialto-Colton Basin underlies a portion of the Upper Santa Ana Valley in southwestern San Bernardino County and northwestern Riverside County and has approximately 1.75 million AF of usable storage and includes several principal recharge
38 areas where supplemental water is delivered for groundwater recharge.
Supplemental water consists of either captured stormwater or purchased imported water from the State Water Project. The basin was adjudicated under the 1961 Rialto-Colton Basin Court Decree. The groundwater management plan for the Rialto-Colton Basin is contained within the 1961 Rialto-Colton Basin Court Decree, the Rialto Basin Settlement Agreement, Western Judgement, and the Rialto Basin Groundwater Council (RBGC) Framework Agreement (2021). According to the DWR Bulletin 118 (California’s Groundwater), DWR has not identified the Rialto-Colton Basin as one of the basins being in “critical condition of overdraft”.
The Rialto-Colton Basin Court Decree defines water rights for a portion of the Rialto-Colton Basin, the northwestern half of the basin. Under the Decree, when the three index wells average mean groundwater level elevation is above 1002.3 feet msl measured during March, April, and May of each year, there are no restrictions on groundwater production from the basin. When the average mean groundwater falls below 1002.3 feet msl and is above 969.7 feet msl, parties to the Decree are limited to a total groundwater production which equates to their fixed right plus adjustable rights. When the mean groundwater level elevation falls below 969.7 feet msl, groundwater production capacity is reduced by one percent per foot below the 969.7 feel msl level, but shall be limited to a maximum 50-percent of each parties adjustable rights. In 2020, groundwater level elevation was measured below 969.7 feel msl and resulted in a 29-percent reduction in allowable groundwater production from the basin. These conditions are imposed on all parties stipulated in the 1961 Rialto-Colton Basin Court Decree.
The City and the Fontana Water Company produce groundwater from a small area, known as “No Man’s Land”, adjacent to the boundary of the Rialto-Colton Basin as defined in the 1961 Decree. No Man’s Land is believed to be within the Rialto-Colton subbasin. To manage the No Man’s Land groundwater basin area, the City of Rialto, City of Colton, West Valley Water District, San Bernardino Valley MWD, Cucamonga Valley Water District, and Fontana Water Company entered into a Settlement Agreement in 2018. The Settlement agreement established reallocated groundwater production to account as part of total Rialto- Colton Basin production. As part of the Settlement Agreement, the parties agreed to form the Rialto Basin Groundwater Council, which was established in 2021 to develop and implement a sustainable groundwater management plan and restore groundwater levels. Both
39 the City and Fontana Water Company are members of the Rialto-Colton Groundwater Council.
Under the Western Judgement, three index groundwater wells are located in the Rialto-Colton Basin and the Riverside North Basin to annually measure and assist with managing groundwater level elevations. If the static groundwater level elevation for the index wells is below 822.04 feet msl, the Non-Plaintiff Parties (defined under Section
5.3) are obligated to recharge the basin by purchasing supplemental imported water and/or reduce groundwater production. Water rights for the Rialto-Colton Basin are not defined in the Western Judgement or the Rialto-Colton Basin Court Decree. To assist with basin management, San Bernardino Valley MWD estimated safe yield based on historical groundwater level elevations. The estimate used the period of 1979 through 2014 to establish the average groundwater production of 13,623 AFY for both Plaintiff and Non-Plaintiff Parties. The Western Judgement established 10,242 AFY of annual production safe yield for the Non- Plaintiff Parties. Safe yield is a groundwater management goal representing a long-term balance between the amount of groundwater recharged and withdrawn from the aquifer.
In recent years, groundwater production from the Rialto-Colton Basin has been impacted due to groundwater contamination of volatile organic compounds and perchlorate. A groundwater treatment program has been established to extract and remove the contamination from the groundwater basin and provides the City with the ability to secure all of their water rights in the basin. To mitigate impacts from groundwater contamination, the City entered in agreement with the County of San Bernardino to lease 1,600 AFY of its water rights in order to allow the San Gabriel Valley Water Company to extract and remove volatile organic compounds from the contamination plume. As part of the conditions with the County of San Bernardino, the City received funding to construct a new groundwater well to replace the quantity of groundwater leased to the County of San Bernardino. A copy of the agreements with the County of San Bernardino and San Gabriel Valley Water Company is provided in Appendix X.
The City has a total water right allocation in the Rialto-Colton Basin of 4,366 AFY, includes 1,520 AFY of fixed rights and 2,846 AFY adjustable rights that are subject to the restrictions previously mentioned. The Fontana Water Company has a total water right allocation in the Rialto- Colton Basin of 5,934 AFY, includes 370 AFY of fixed rights, 550 AFY
40 adjustable rights, and 5,014 AFY of adjustable rights in No Mans Land that are subject to the restrictions previously mentioned. Over the last ten years, the average percent reduction has been approximately 30- percent. Pursuant to the 1961 Decree and declining groundwater elevations in the three index wells, both parties forecast a 30-percent reduction to its adjustable rights in 2025. The reduction is anticipated to reduce by two percent every five years thereafter (e.g. 28-percent reduction in 2030) and is a result of implementing the programs and policies of the Rialto Basin Groundwater Council and pursuing supplemental imported water supply to recharge the basin.
The Rialto-Colton Basin is a source of water supply for the City and Fontana Water Company. Historical groundwater production from the Rialto-Colton Basin is shown in Table 5.1 and 5.2. Projected future production from the Rialto-Colton Basin in normal, single-dry, and multiple-dry years is shown in Tables 7.1 and 7.2.
Riverside Arlington Basin
The Riverside-Arlington Basin (Basin No. 8-2.03) is a subbasin of the Upper Santa Ana Valley Basin (Basin Number 8-2) contained within the DWR’s South Coast Hydrologic Region. The Riverside-Arlington Basin underlies a portion of the Upper Santa Ana Valley in southwestern San Bernardino County and northwestern Riverside County and has approximately 243,000 AF of usable storage with little to no principal recharge areas where supplemental water could be delivered for groundwater recharge. This subbasin is bound by impermeable rocks of Box Springs Mountains on the southeast, Arlington Mountain on the south, La Sierra Heights and Mount Rubidoux on the northwest, and Jurupa Mountains on the north. The northeast boundary is formed by the Rialto-Colton fault, and a portion of the northerly boundary is a groundwater divide beneath the city of Bloomington. The groundwater divide is an alluvial separation that divides the Riverside portion from the Arlington portion of the subbasin. The Riverside-Arlington Basin has no artificial recharge areas and is replenished by infiltration from Santa Ana River flows, underflow from the Rialto-Colton fault, intermittent underflow from the Chino Basin (DWR Basin No. 8-2.01), applied water from irrigation, and percolation of precipitation. (DWR Bulletin 118).
The Riverside-Arlington Basin is partially adjudicated under the Western Judgement. The Watermaster manages groundwater under the adjudicated portion of the basin. The groundwater management plan for the Riverside-Arlington Basin is contained within the Western
41 Judgement. According to the DWR Bulletin 118 (California’s Groundwater), DWR has not identified the Riverside-Arlington Basin as one of the basins being in “critical condition of overdraft”.
The Western Judgement includes the portion of the Riverside-Arlington Basin upstream of Riverside Narrows. Groundwater extractions in the Riverside North Groundwater Basin (the portion of the Riverside Basin area that is located in San Bernardino County) are governed by the Western Judgement. Under the Western Judgement, water rights for use in Riverside County are limited to 21,085 AFY and groundwater extractions for use in San Bernardino County are unlimited, provided that the groundwater level elevations at the three index groundwater wells are above 822.04 feet msl. Based on estimated prepared under the 2015 IRWMP, it was determined that the estimated sustainable supply from the Riverside North Basin for use in San Bernardino County was 30,100 AFY, based on historical groundwater level elevation records and will be used for the purpose of this document.
The Riverside-Arlington Basin is a source of water supply for the City. The City’s historical groundwater production from the Riverside-Arlington Basin is shown in Table 5.1. Projected future production from the Riverside-Arlington Basin in normal, single-dry, and multiple-dry years is shown in Tables 7.1.
Lytle Creek Basin
Lytle Creek Basin is part of the San Bernardino Basin and is not identified as a separate subbasin in DWR Bulletin 118; however, the subbasin is an integral part of the Upper Santa Ana Valley Groundwater Basin.
Historically, local agencies have recognized the Lytle Creek subbasin as a distinct groundwater subbasin. In the Western Judgment, the Bunker Hill and Lytle Creek subbasins are combined into the San Bernardino Basin. Sediments within the Lytle Creek subbasin are, for the most part, highly permeable, and the aquifer has a high specific yield. High permeability and specific yield tend to result in an aquifer that responds rapidly to changes in inflow (precipitation and streamflow) and outflow (groundwater pumping, streamflow, and subsurface outflow). Lytle Creek subbasin is adjoined on the west by the Rialto-Colton Basin along the Lytle Creek fault, and on the east and southeast by the Bunker Hill Basin along the Loma Linda fault and Barrier G. The northwestern border of the subbasin is delineated by the San Gabriel Mountains, and runoff from the mountains flows south through Lytle and Cajon Creeks into the basin. It is important to note that the water rights in Lytle Creek Basin
42 are set forth in long-standing court judgments governing the rights of the parties. The Lytle Creek Basin was adjudicated under the 1924 Judgment No. 17,030 from the Superior Court of San Bernardino County and is managed by the Lytle Creek Water Conservation Association, which is made up of the successors to the stipulated parties of the judgment. The City can divert up to a maximum of 115.63 miner’s inches and the Fontana Water Company can divert up to 3,480.78 miner’s inches from the basin. Additional information regarding each parties surface water rights is described below. A copy of the 1924 Judgment is provided in Attachment XX.
The Lytle Creek Basin is a source of water supply for the City and Fontana Water Company. Historical groundwater production from the Lytle Creek Basin is shown in Table 5.1 and 5.2. Projected future production from the Lytle Creek Basin in normal, single-dry, and multiple-dry years is shown in Tables 7.1 and 7.2.
Summary of Groundwater Rights
Table 5.1 summarizes the groundwater rights owned and utilized, pursuant to court-approved agreements by the City. Copies of the agreements are included in Appendix XX.
Table 5.1: Summary of Groundwater and Diversion Rights
Source of
Supply
Water Right or
Contract Description
Chino
Basin
Chino Basin
Judgement, 1978
Unrestricted pumping, subject to
replenishment through Watermaster
Safe Yield = 131,000 AFY through 2030
Fontana Water Company receives 11.68
percent of operating safe yield. Rialto
does not pump groundwater from this
basin.
Bunker
Hill Basin
Western-San
Bernardino
Judgement, 1961
Unrestricted pumping, subject to
replenishment through Watermaster.
Safe Yield = 232,100 AFY
Non-Plaintiffs, which includes the City of
Rialto, receive 72.05 percent of the
natural safe yield. Fontana Water
Company does not pump groundwater
from this basin.
43 Table 5.1: Summary of Groundwater and Diversion Rights Source of
Supply
Water Right or
Contract Description
Rialto-
Colton
Basin
Rialto-Colton
Basin Decree, 1961
Rialto Basin
Groundwater
Council
Framework
Agreement
Settlement
Agreement
Wester-San
Bernardino
Judgement, 1961
Adjustable rights subject to reductions
based on groundwater level elevations
at Index wells.
Rialto Fixed Rights = 1,520 AFY
Rialto Adjustable Rights = 2,846 AFY
Rialto Water Right Lease = 1,600 AFY
Fontana Fixed Rights = 370 AFY
Fontana Adjustable Rights = 550 AFY
Fontana Adjustable Rights (No Man’s
Land) = 5,014 AFY
Lytle
Creek
Basin
Lytle Judgement
1897 McKinley
Decree
1924 Judgment
Rialto can divert up to 115.63 miner’s
inches from the Lytle Creek Region (~
1,600 AFY)
Fontana can divert up to 3,480.78
miner’s inches from the Lytle Creek
Region (~50,400 AFY). This includes up
to 1,300 miner’s inches of groundwater
production.
Riverside-
Arlington
Basin
Western-San
Bernardino
Judgement, 1961
Unrestricted pumping, subject to
replenishment through Watermaster
and groundwater level elevations at
Index wells.
Safe Yield (estimated) = 30,100 AFY
Rialto’s estimated yield is approximately
1,200 AFY based on historical
production. Fontana Water Company
does not pump groundwater from this
basin.
5.2 Surface Water
The City and Fontana- Water Company have rights to divert surface flows and groundwater from the Lytle Creek Basin. The Lytle Creek Basin flows through the eastern San Gabriel Mountains and has three forks, the North, Middle, and
44 South forks. Lytle Creek is part of the Lytle Creek Watershed and originates near Mount San Antonio in the San Bernardino National Forest. Surface water from Lytle Creek is used by Southern California Edison to generate hydroelectric power and then continues downstream for diversion and treatment by the City, Fontana Water Company, and other water purveyors with diversion rights.
Lytle Creek
The City has a total diversion right of 115.63 miner’s inches, approximately 1,600 AFY of surface water diversion rights in Lytle Creek. The Fontana Water Company has a total diversion right of 3,480.78 miner’s inches, approximately 50,400 AFY of surface water diversions. The surface water diversion rights for Lytle Creek were determined in the 1897 McKinley Decree entered in Los Angeles Superior Court Case No. 20.790. The City obtained their diversion rights from ownership of stock in the Lytle Creek Water & Improvement Company and purchasing the Rialto Domestic Water Company. The City owns 21.98% of the shares of the Lytle Creek Water & Improvement Company and obtained an additional 72.4 miner’s inches from its stock share. After purchasing the Rialto Domestic Water Company, they secured an additional 43.23 miner’s inches. Fontana Water Company’s total diversion right includes rights for Fontana Union Water Company and Fontana Water Company.
The City and Fontana Water Company try to utilize all their surface water diversion rights in the Lytle Creek Basin. Surface water that is diverted to the City is sent and treated at the Oliver Roemer Water Filtration Facility owned and operated by the West Valley Water District. In 1995, the City executed an agreement with West Valley Water District to jointly construct the Oliver Roemer Water Filtration Facility to treat Lytle Creek surface water rights for potable water uses. The City owns 1.5 MGD of treatment capacity in the facility. Surface water that is diverted to the Fontana Water Company is sent and treated at the Summit Surface Water Treatment Plant owned and operated by the Fontana Water Company.
When surface flows from Lytle Creek drop below 7,182 gpm (798 miner’s inches), all diversion right holders must reduce their diversions in accordance with the schedule set forth by the 1897 Decree. If the City and Fontana Water Company are not able to receive their full Lytle Creek surface water diversion right, they are permitted to make up the difference by pumping additional groundwater from the Lytle Creek Basin.
45 The Lytle Creek Basin is a source of water supply for the City and Fontana Water Company. Historical surface water diversions from the Lytle Creek Basin is shown in Table 5.1 and 5.2. Projected future surface water diversions from the Lytle Creek Basin in normal, single-dry, and multiple- dry years is shown in Tables 7.1 and 7.2.
5.3 Stormwater
The City and Fontana Water Company collaborate with regional water service provides to develop and implement regional stormwater capture projects to assist with capturing and diverting stormwater for groundwater recharge.
These efforts increase groundwater reliability and align with sustainable groundwater basin management planning efforts as part of the San Bernardino Basin and Rialto-Colton Groundwater Council initiatives.
Additional information on regional efforts can be found in the City of Rialto’s 2020 IRUWMP, Part 1, Chapter 3..
5.4 Recycled Water
The City maintains and operates a sewer collection and wastewater treatment facility. In 2020, approximately 3 MGD of wastewater was collected and the Rialto Wastewater Treatment Plant (WWTP) that was generated within the City’s water service area. The WWTP also collects and treats sewer flows from the West Valley Water District and portion of the City of Fontana service areas through Extra-Territorial Agreements. The current treatment capacity of the WWTP is 11.7 MGD and has an average daily flow of approximately 7 MGD. The city currently has limited uses for recycled water and is currently only used for freeway landscape irrigation and remaining is discharged to the Santa Ana River. The City is currently having discussions with regional parties to identify potential uses and associated projects for maximizing the reuse of recycled water. Today, the city’s current recycled water demand is approximately 10 AFY and will be the planning assumption as part of this effort.
IEUA is the regional wastewater treatment provider to the Cities of Chino, Chino Hills, Fontana, Montclair, Ontario, Upland, and Rancho Cucamonga.
IEUA treats approximately 50 MGD of wastewater from its regional treatment plants and beneficially reuses over 30,000 AFY to increase local water supply reliability, enhance groundwater level elevations, and reduce dependance of imported water supply. To increase recycled water use, the Fontana Water Company executed an agreement with the City of Fontana for the direct use of recycled water in the southern portion of their service area, along with purchasing recycled water from groundwater recharge. The City of Fontana is
46 entitled to use up to approximately 12,000 AFY of treated recycled water from IEUA.
Recycled water is a source of water supply for the City and Fontana Water Company. Historical recycled water use for each party is shown in Table 5.1 and
5.2. Projected future recycled water usage in normal, single-dry, and multiple- dry years is shown in Tables 7.1 and 7.2
5.1 Exchanges, Transfers, and Emergency Supply
The City and Fontana Water Company do not exercise regular or long-term water supply transfers or exchanges. Any transfers or exchanges would be determined on an as-needed basis to mitigate emergency or catastrophic events. In preparation for such events, both parties have emergency and stand-by agreements. The City has agreements with the City of San Bernardino, West Valley Water District, Riverside-Highland Water Company, and Fontana Water Company. Fontana Water Company has agreements with the Cucamonga Valley Water District, and West Valley Water District. Since these are non-normal water supply agreements, water supply from these arrangements is not included as part of this evaluation.
Table 5.1: City of Rialto Historical Water Supply by Source, AFY Primary Water
Source
Retail
Agency Location or Basin Name 2016 2017 2018 2019 2020 2021 Groundwater Rialto Bunker Hill Basin 1,963 514 1,268 912 1,508 2,209 Groundwater Rialto Bunker Hill via Baseline Feeder 1,478 1,625 1,827 1,740 1,668 1,357 Groundwater Rialto Lytle Basin 1,332 2,130 2,143 1,252 999 1,692 Groundwater Rialto Rialto-Colton 1,113 1,456 1,818 1,543 2,015 1,983 Groundwater Rialto North Riverside-Arlington 1,389 1,608 694 1,110 1,156 617 Surface Water Rialto Lytle Creek Surface Diversion 0 0 0 0 1,583 967 Recycled Rialto Wastewater Treatment Plant 0 0 0 0 0 0 Imported Water Rialto Rialto Groundwater Council 0 0 0 0 0 0 Total Water Supply Rialto Rialto Water Service Area 7,275 7,333 7,750 6,557 8,929 8,825
Table 5.2: Fontana Water Company Historical Water Supply by Source, AFY Primary Water
Source
Retail
Agency Location or Basin Name 2016 2017 2018 2019 2020 2021 Groundwater Fontana Chino 16,299 10,640 10,796 9,351 11,859 13,830 Groundwater Fontana Lytle Basin 2,649 4,111 5,148 6,046 6,422 6,095 Groundwater Fontana Rialto-Colton 2,563 2,378 2,679 2,469 2,538 3,204 Groundwater Fontana Rialto-Colton (No Man's) 4,341 4,533 4,069 3,143 2,633 2,171 Surface Water Fontana Lytle Creek Surface Diversion 1,419 3,867 2,298 3,869 5,966 2,658 Recycled Fontana Inland Empire Utilities Agency 7 128 163 149 387 358 Imported Water Fontana Inland Empire Utilities Agency 7,617 11,824 12,961 10,771 10,027 12,023 Imported Water Fontana San Bernardino Valley MWD 0 0 0 0 0 0 Total Water Supply Fontana Fontana Water Service Area 42,512 49,305 51,075 46,569 49,859 40,339
48 6 Demand Management Measures
Knowing the degree of variability in Southern California’s hydrology and impact on local water supplies, there has been an increased focus on water conservation and efficiency measures at the state, regional, and local levels. In 2009, the state Legislature passed Senate Bill 7 (SBX7-7), more commonly known as “20x2020”. This law seeks to achieve a 20-percent reduction in urban per capita water use across California by 2020. The law also defined methodologies to define water use targets and reporting requirements indented to promote conservation standards with the California Urban Water Conservation Council (CUWCC) Best Management Practices. The following summary of programs are currently administered by the City and are used to assist with promoting efficient water use. If needed, the City can increase conservation programming and implement higher restrictive water use stages under its water waste prevention ordinance to aid in managing water demands and available supplies.
6.1 Water Use Efficiency and Conservation Programs
In 2009, the City joined the CUWCC and has implemented several demand management practices. The City recognizes the importance of these measures for water supply reliability and sustainable use practices and has made a commitment to comply with SBX7-7. The following water use efficiency and conservation programs are currently administered by the City. o Water Waste Prevention Ordinance No. 1560 - outlines efficient water use measures and four stages of increasingly restrictive prohibition with related penalties for non-compliance.
o Metering Program – establish policy to replace all existing meters and have new water services as part of a routine calibration and replacement program to continually improve accurate meter readouts. o Conservation Pricing – the City administers a tiered rate structure to promote economic incentives to customers who use water efficiently. o Public Education and Outreach Programming – the City actively participates in local and community outreach events, market rebates and incentives to its customers through water bill inserts, and uses multiple social media outlets and business forums to communicate with customers. Monthly bills include consumption charts and comparison metrics to promote efficient use and increase the customers awareness in achieving conservation targets.
49 o Program to Assess and Manage System Losses – the City administers leak detection program to decrease leak response time and minimize overall water loss throughout the distribution system.
o Water Conservation Program Coordination and Support - the program has sponsors landscaping classes for the community taught by professionals to promote more drought tolerant landscaping. o Incentive Programs – the City offers rebates and incentives to all water customers promoting efficient water use behaviors. Current rebates offered to all customers include installation of high efficiency toilets, high efficiency washing machines, weather based smart irrigation timers, automatic shut off nozzle and turf replacement.
7 Current and Projected Future Water Supply
Tables 7.1 and 7.2 provide a summary of current and future water supplies under normal year conditions, average hydrology for the City of Rialto and Fontana Water Company. The City anticipates no future changes to its existing water supply portfolio and will therefore remain unchanged through the planning period for this evaluation. With most of the the City’s water supply from large groundwater basins with significant storage, limited yearly variability from the type of water year is realized. Yearly changes in the quantity of water supply are further minimized by the implementation of sustainable groundwater management actions currently administered within the local groundwater basins. Under dry year conditions, the City will produce additional groundwater from the Bunker Hill Basin, and the Fontana Water Company produces additional groundwater from the Chino Basin to provide 100-percent of the remaining water supply. Additional information about local groundwater management actions can be found in Section 5.
7.1 Water Supply Reliability
This section evaluates the availability of water supplies during single-dry and multiple-dry water years. Although the City does not anticipate future changes in water supply, the following section highlights potential factors that could limit and reduce the expected quantity of water supply available from the City or the Fontana Water Company through the 2045 planning period.
Water Quality Impacts
Water quality is a major concern for many water utilities, including the City, as most of their water supply comes from groundwater sources.
50 Over the years, water quality legislation and the detection of groundwater plumes of various chemical pollutants has challenged the ability to increase or even maintain local water supplies. Many of the water quality challenges present would require the installation of a treatment facility or must be blended with a higher quality water source before delivering the water into the service area. In 2005, the City adopted a zero-tolerance perchlorate contamination policy which ultimately took existing groundwater wells out of service that tested positive with detectable levels of perchlorate. Clean up efforts are by agreement with the San Bernardino County and Emhart, in coordination with the U.S. Environmental Protection Agency and the Santa Ana Regional Water Quality Control Board. The City has proactively managed water quality challenges by implementing necessary treatment and as a result, is not expecting water quality impacts to the City’s water supplies or corresponding water supply reliability.
Climate
Local groundwater and surface water supplies are influenced by climate.
The City and the Fontana Water Company are in semi-arid climate and located at the base of the San Bernardino mountains in the interior valley. The climate of the area can be characterized as having relatively hot, dry summers and cool winters. The largest position of precipitation occurs during the winter months of December through March with snowfall in the San Bernardino mountains above 6,000 feet msl. Based on historical records, the region has been experiencing below-average precipitation since 1999. Temperature increases are also expected to occur throughout the inland valley. (2020 UWMP Part 1, Table 2-3) In extended drought conditions, surface water supply in the Lytle Creek region can be severely impacted and groundwater in the Basin has experienced a drop in groundwater level elevation over 300 feet. As a result, the City and Fontana Water Company are vulnerable to water shortages due to seasonal hot weather and climate variability. Since both water purveyors receive groundwater from multiple adjudicated groundwater basins and managed by the Chino and Wester-San Bernardino Watermaster’s in collaboration with the local Groundwater Councils, groundwater levels are monitored regularly and supplemental imported water for groundwater recharge is purchased to maintain long term sustainability of the basins.
51 Regulatory Conditions
Current and emerging regulatory conditions associated with groundwater quality could impact both water purveyors if emerging contaminants are tested at levels exceeding the proposed maximum contaminant levels.
7.2 Water Year Characterization
This section evaluates the availability of water supplies during single-dry and multiple-dry year water years for the proposed project. "Normal Year" refers to the water supply available under standard conditions, during a normal year. This could pertain to a single year or an average calculated from several years that best represents average water supply conditions
Single-dry year is the year that represents the lowest water supply available to the Project.
Multiple-dry year period represents the lower average supply available to the Project for a consecutive five-year period.
With most of the water supply coming from groundwater sources, there is limited yearly variability due to the large size of the groundwater basin and associated storage capacity. Yearly impacts are further minimized by the sustainable groundwater management actions that the City and Fontana Water Company participate in which identifies supplemental water supply requirements (purchased imported water for stormwater/recycled water recharge) for groundwater recharge and storage.
In years with below-average hydrology, pumping rights from the Rialto Basin and surface water could potentially be reduced. However, the City has the flexibility to shift its groundwater pumping from the Bunker Hill Basin, Lytle Creek Basin, and Riverside-Arlington Basin to meet water demands during dry years. The City’s total groundwater supplies are not reduced in dry years and 2020 is considered the base year for all year types. Fontana Water Company can also shift groundwater production and will produce additional groundwater from the Chino Basin as necessary to provide 100-percent of the remaining water supply under all dry year conditions. The City and Fontana Water Company do not anticipate a supply shortage in a single-dry or multiple-dry year event.
52 7.3 Future Water Supply Projects
The City does not currently have plans for developing new water supply projects but does participate and invest in sustainable groundwater management planning efforts. These efforts consist of purchasing supplemental imported water for groundwater recharge and potential development of groundwater diversion and recharge projects to enhance groundwater level elevations and overall reliability of the underlying groundwater basins. Although not a new water supply project, the City does recognize the importance of sustainable use practices and is committed to implementing water use efficiency and conservation measures in accordance with the California Urban Water Conservation Council and accompanying legislation.
Under existing supply conditions, both water purveyors first maximize surface water supply from Lytle Creek, when available, and groundwater production rights from the various adjudicated groundwater basins. Any deficits between water supply and demand are met by pumping additional water from groundwater storage or purchasing supplemental imported water for direct delivery (only Fontana Water Company). Both water purveyors participate in sustainable water management activities that identify the need to purchase supplemental imported water for groundwater recharge and storage.
7.4 Single-Dry and Multiple-Dry Year Water Supplies
Table 7.1 provides a summary of the current and future water supplies under single-dry and multiple-dry year conditions for the proposed project. Based on the assessment performed in the 2020 IRUWMP, the City applied a Reliability Factor of 10-percent to their water supply reliability analysis to account for future uncertainties in supply projections. This recommendation comes from the results of a study done by RAND Corporation that evaluated uncertainty factors in regional supply and demand projections. Additional information can be found in Part 1, Chapter 5 of the 2020 IRUWMP on how the Reliability Factor was established.
Future water supply projections for this evaluation are consistent with the methodology established under the 2020 IRUWMP and will be the basis of projection for the City. If additional water supply is necessary to meet water demands during a single-dry and multiple-dry year condition, groundwater supply from the Bunker Hill Basin will be increased as necessary to provide 100- percent of the remaining water supply.
53 The Fontana Water Company established current and future water supplies under single-dry and multiple-dry year conditions based on historical record.
Additional information can be found in Section 7 of their 2020 Urban Water Management Plan. For this evaluation, the total water supply required from the Fontana Water Company was estimated based on the additional water supply required by the proposed project. Water supply needs for the existing area were included as part of their 2020UWMP. As indicated in Section 7, Fontana Water Company will produce additional groundwater from the Chino Basin to meet 100-percent of the remaining water supply during a single-dry and multiple-dry year condition. Table 7.2 provides a summary of the supply availability from Fontana Water Company for the proposed project area.
Table 7.1: City of Rialto Projected Water Supply by Source, AFY Primary Water
Source
Retail
Agency Location or Basin Name 2025 2030 2035 2040 2045
Groundwater Rialto Bunker Hill Basin1 2,580 3,227 3,875 4,270 4,665 Groundwater Rialto Bunker Hill via Baseline Feeder 2,500 2,500 2,500 2,500 2,500 Groundwater Rialto Lytle Basin 1,600 1,600 1,600 1,600 1,600 Groundwater Rialto Rialto-Colton 1,528 1,557 1,586 1,614 1,642 Groundwater Rialto North Riverside-Arlington 1,200 1,200 1,200 1,200 1,200 Surface Water Rialto Lytle Creek Surface Diversion 1,241 1,241 1,241 1,241 1,241 Recycled Rialto Wastewater Treatment Plant 10 10 10 10 10 Imported Water3 Rialto Rialto Groundwater Council 384 412 440 469 498 Total Water Supply Rialto Rialto Water Service Area 11,043 11,747 12,452 12,904 13,356
Planning Projections
Normal Year Rialto Rialto Water Service Area 11,043 11,747 12,452 12,904 13,356 Single-Dry 1,2,3 Rialto Rialto Water Service Area 11,763 12,510 13,256 13,725 14,193 Multiple-Dry 1,2,3 Rialto Rialto Water Service Area 11,763 12,510 13,256 13,725 14,193
Notes:
(1) Supply from the Bunker Hill Basin will increase as necessary to provide 100-percent of the remaining water supply under all dry year conditions. (2) Water supply assumed to increase by 10-percent in single-dry and multiple-dry year conditions to accommodate anticipated increase in water demand above normal year demand. Additional groundwater is pumped from groundwater storage during dry year conditions to meet 100-percent of the remaining water demand.
(3) For dry year conditions, imported water purchased under the Rialto Groundwater Council is assumed to be not available and therefore not included in the single-dry and multiple-dry year supply projections.
Table 7.2: Fontana Water Company Projected Water Supply by Source, AFY Primary Water
Source
Retail
Agency Location or Basin Name 2025 2030 2035 2040 2045
Groundwater Fontana Chino 9,278 9,983 11,128 12,293 13,183 Groundwater Fontana Lytle Basin 6,390 6,390 6,390 6,390 6,390 Groundwater Fontana Rialto-Colton 5,865 5,976 6,087 6,199 6,310 Groundwater3 Fontana Rialto-Colton (No Man's) 0 0 0 0 0 Surface Water Fontana Lytle Creek Surface Diversion 4,860 4,860 4,860 4,860 4,860 Recycled Fontana Inland Empire Utilities Agency 1,000 1,500 2,000 2,500 3,000 Imported Water Fontana Inland Empire Utilities Agency 15,000 15,000 15,000 15,000 15,000 Imported Water Fontana San Bernardino Valley MWD 3,200 3,200 3,200 3,200 3,200 Total Water Supply Fontana Fontana Water Service Area 45,593 46,909 48,665 50,442 51,943
Planning Projections
Normal Year Fontana Fontana Water Service Area 45,593 46,909 48,665 50,442 51,943 Single-Dry 1,2 Fontana Fontana Water Service Area 34,006 34,987 36,297 37,623 38,742 Multiple-Dry 1,2 Fontana Fontana Water Service Area 36,526 37,580 38,987 40,411 41,613
Notes:
(1) Supply from Chino Basin will increase as necessary to provide 100-percent of the remaining water supply under all dry year conditions. (2) Quantities for multiple-dry year conditions vary by year per Table 7-6 in Fontana Water Company’s 2020 Urban Water Management Plan. The values provided are total supply projections at the end of the fifth year. (3) Production from No Man’s Land is included as part of Rialto-Colton Basin groundwater production per the Rialto Basin Groundwater Council Framework Agreement.
56 8 Water Supply Adequacy and Reliability
Evaluation
This section provides a detailed assessment of whether the total projected water supplies available to the City and Fontana Water Company during normal, single-dry, and multiple-dry year conditions over the next 20 years are sufficient to meet the projected water demand associated with the proposed Project, in addition to existing and planned future water uses. While the City water demand in Tables 8.1 through 8.3 are based on 2020 retail water demands from the adopted water master plan, it should be noted that actual water demand for calendar year 2021 was 8,825 and 2022 was 7,837 AFY which is lower than the base 2020 water demand estimate. This trend is also relevant to the Fontana Water Company, with calendar year 2021 (40,339 AFY) and 2022 (36,752 AFY) water demand also coming in significantly lower than 2020 usage.
Therefore, the surplus supply displayed in Tables 8.1 through 8.3 are a conservative assessment when compared to actual water demand for the City.
The quantity of water supply that would be available during single-dry and multiple-dry years at buildout are summarized in Tables 7.1 through 7.2.
8.1 Normal Water Year
Table 8.1 illustrates water supply and demand projections under normal supply and demand conditions. The total net increase in annual water demand for the proposed Project is estimated at 794 AFY. Table 8.1 demonstrates that the City and the Fontana Water Company (portion of proposed Project served) will have sufficient water supply in a normal year scenario to serve existing, planned future uses, and the projected net increase in water demand of the proposed Project over the 20-year evaluation period.
8.2 Single Dry Year
Table 8.2 illustrates water supply and demand projections under a single-dry year supply and demand condition, which assumes water demands will increase by 10-percent above normal year conditions and no supplemental imported water for groundwater recharge would be available for purchase.
Assuming no supplemental imported water is available for groundwater recharge is a conservative measure to capture the potential legal, regulatory, climatic, and environmental factors that have the potential to affect the availability and reliability of SWP supplies. Additional information on imported water reliability can be found in the 2020IRUWMP. The total net increase in
57 annual water demand for the proposed Project is estimated at 873 AFY. Table
8.2 demonstrates that the City and the Fontana Water Company (portion of proposed Project served) will have sufficient water supply in a single-dry year scenario to serve existing, planned future uses, and the projected net increase in water demand of the proposed Project over the 20-year evaluation period.
8.3 Multiple Dry Year
Table 8.3 illustrates water supply and demand projections under a multiple-dry year supply and demand condition, which assumes water demands will increase by 10-percent above normal year conditions and no supplemental imported water for groundwater recharge would be available for purchase.
Assuming no supplemental imported water is available for groundwater recharge is a conservative measure to capture the potential legal, regulatory, climatic, and environmental factors that have the potential to affect the availability and reliability of SWP supplies. Additional information on imported water reliability can be found in the 2020 IRUWMP. The total annual net increase in water demand for the proposed Project is estimated at 873 AFY.
Table 8.3 demonstrates that the City and the Fontana Water Company (portion of proposed Project served) will have sufficient water supply in a multiple-dry year scenario to serve existing, planned future uses, and the projected net increase in water demand of the proposed Project over the 20-year evaluation period.
58 Table 8.1: Water Supply Adequacy and Reliability Evaluation under Normal Year Scenario, AFY Primary Water Source Retail
Agency Location or Basin Name 2020 2025 2030 2035 2040 2045 Water Supply Planning Projection
Normal Year Rialto Rialto Water Service Area 8,929 11,043 11,747 12,452 12,904 13,356 Normal Year 1,2 Fontana SPU Service Area 107 112 114 117 119 121 Planning Projection Combined Estimated Water Supply 9,036 11,155 11,861 12,569 13,023 13,477
Water Demand Planning Projection
Normal Year Rialto Rialto Water Service Area 8,929 8,960 8,967 9,343 9,585 9,826 Normal Year 1 Fontana SPU Service Area 107 112 114 117 119 121 Anticipated and Future Developments
New Demand Since 2020 3 Completed or Approved 0 497 497 497 497 497 Anticipated Demand 4 Near-Term Developments 0 0 50 50 50 50 Planning Projection Combined Estimated Water Demand 9,036 9,569 9,628 10,007 10,251 10,494
Estimated Water Supply Less Water Demand 0 1,586 2,233 2,562 2,772 2,983
Propose Net Increase in Project Water Demand – SPU 5 0 769 769 769 769 769
Water Supply Sufficiency - Potential Surplus / (Shortfall) 0 817 1,464 1,793 2,003 2,214
Notes:
(1) The estimated portion of water supply from Fontana Water Company is based on their percentage of total anticipated demand for the corresponding area served within the Foothill Central Specific Plan Update area. (2) Water supply associated with the area of the Foothill Central SPU serviced by the Fontana Water Company will come from a combination of water supply sources.
Based on the supply reliability assessment, Section 7 of the Fontana Water Company Urban Water Management Plan, groundwater supply from the Chino Basin will increase as necessary to provide 100-percent of the remaining water demand. Therefore, total water supply will equal total water demand associated with the portion of the Foothill Central SUP serviced by the Fontana Water Company under this evaluation. (3) In coordination with the City of Rialto, XX new development sites have been completed, in-progress, or have already been approved by City Council post 2020.
Refer to Section 3.4 for additional information regarding new demand associated with developments and infill projects completed since 2020. (4) Anticipated development projects that the city has identified as commencing pre-development services and likely to receive approval in the near-term. Refer to Section 3.4 for additional information regarding new demand associated with developments and infill projects completed since 2020. (5) Net increase in demand associated with the proposed Foothill Central SPU was applied to start in the 2025 forecast as a conservative planning measure as the likelihood of realizing the full extent of demand associated with the Project is unlikely.
59 Table 8.2: Water Supply Adequacy and Reliability Evaluation under Single-Dry Year Scenario, AFY Primary Water Source Retail
Agency Location or Basin Name 2020 2025 2030 2035 2040 2045 Water Supply Planning Projection
Single-Dry 1 Rialto Rialto Water Service Area 8,929 11,763 12,510 13,256 13,725 14,193 Single-Dry 2,3 Fontana SPU Service Area 107 123 126 129 131 133 Planning Projection Combined Estimated Water Supply 9,036 11,886 12,636 13,385 13,856 14,326
Water Demand Planning Projection
Single-Dry 4 Rialto Rialto Water Service Area 8,929 9,856 9,863 10,277 10,543 10,809 Single-Dry 4 Fontana SPU Service Area 107 123 126 129 131 133 Anticipated and Future Developments
New Demand Since 2020 4,5 Completed or Approved 0 547 547 547 547 547 Anticipated Demand 4,6 Near-Term Developments 0 0 55 55 55 55 Planning Projection Combined Estimated Water Demand 9,036 10,526 10,591 11,008 11,276 11,544
Estimated Water Supply Less Water Demand 0 1,360 2,045 2,377 2,580 2,782
Proposed Net Increase in Project Water Demand – SPU 4,7 0 846 846 846 846 846
Water Supply Sufficiency - Potential Surplus / (Shortfall) 0 514 1,199 1,531 1,734 1,936
Notes:
(1) Supply from the Bunker Hill Basin will increase as necessary to provide 100-percent of the remaining water supply under all dry year conditions. Single-dry year scenario also assumes no supplemental imported water for groundwater recharge would be available for purchase by the Rialto Groundwater Council. (2) Water supply associated with the area of the Foothill Central SPU serviced by the Fontana Water Company will come from a combination of water supply sources.
Based on the supply reliability assessment, Section 7 of the Fontana Water Company Urban Water Management Plan, groundwater supply from the Chino Basin will increase as necessary to provide 100-percent of the remaining water demand. Therefore, total water supply will equal total water demand associated with the portion of the Foothill Central SPU serviced by the Fontana Water Company under this evaluation. (3) The estimated portion of water supply from Fontana Water Company is based on their percentage of total anticipated demand for the corresponding area served within the Foothill Central Specific Plan Update area. (4) Single-dry year scenario assumes water demands will increase by 10-percent above normal year conditions. (5) In coordination with the City of Rialto, 10 new development sites have been completed, in-progress, or have already been approved by City Council post 2020.
Refer to Section 3.4 for additional information regarding new demand associated with developments and infill projects completed since 2020. (6) Anticipated development projects that the city has identified as commencing pre-development services and likely to receive approval in the near-term. Refer to Section 3.4 for additional information regarding new demand associated with developments and infill projects completed since 2020. (7) Net increase in demand associated with the proposed Foothill Central SPU was applied to start in the 2025 forecast as a conservative planning measure as the likelihood of realizing the full extent of demand associated with the Project is unlikely.
60 Table 8.3: Water Supply Adequacy and Reliability Evaluation under Multiple-Dry Year Scenario, AFY Primary Water Source Retail
Agency Location or Basin Name 2020 2025 2030 2035 2040 2045 Water Supply Planning Projection
Multiple-Dry 1 Rialto Rialto Water Service Area 8,929 11,763 12,510 13,256 13,725 14,193 Multiple-Dry 2,3 Fontana SPU Service Area 107 123 126 129 131 133 Planning Projection Combined Estimated Water Supply 9,036 11,886 12,636 13,385 13,856 14,326
Water Demand Planning Projection
Multiple-Dry 4 Rialto Rialto Water Service Area 8,929 9,856 9,863 10,277 10,543 10,809 Multiple-Dry 4 Fontana SPU Service Area 107 123 126 129 131 133 Anticipated and Future Developments
New Demand Since 2020 4,5 Completed or Approved 0 547 547 547 547 547 Anticipated Demand 4,6 Near-Term Developments 0 0 55 55 55 55 Planning Projection Combined Estimated Water Demand 9,036 10,526 10,591 11,008 11,276 11,544
Estimated Water Supply Less Water Demand 0 1,360 2,045 2,377 2,580 2,782
Proposed Net Increase in Project Water Demand – SPU 4,7 0 846 846 846 846 846
Water Supply Sufficiency - Potential Surplus / (Shortfall) 0 514 1,199 1,531 1,734 1,936
Notes:
(1) Supply from the Bunker Hill Basin will increase as necessary to provide 100-percent of the remaining water supply under all dry year conditions. Multiple-dry year scenario also assumes no supplemental imported water for groundwater recharge would be available for purchase by the Rialto Groundwater Council. (2) Water supply associated with the area of the Foothill Central SPU serviced by the Fontana Water Company will come from a combination of water supply sources. Based on the supply reliability assessment, Section 7 of the Fontana Water Company Urban Water Management Plan, groundwater supply from the Chino Basin will increase as necessary to provide 100-percent of the remaining water demand. Therefore, total water supply will equal total water demand associated with the portion of the Foothill Central SPU serviced by the Fontana Water Company under this evaluation. (3) The estimated portion of water supply from Fontana Water Company is based on their percentage of total anticipated demand for the corresponding area served within the Foothill Central Specific Plan Update area. (4) Multiple-dry year scenario assumes water demands will increase by 10-percent above normal year conditions. (5) In coordination with the City of Rialto, 10 new development sites have been completed, in-progress, or have already been approved by City Council post 2020.
Refer to Section 3.4 for additional information regarding new demand associated with developments and infill projects completed since 2020. (6) Anticipated development projects that the city has identified as commencing pre-development services and likely to receive approval in the near-term. Refer to Section 3.4 for additional information regarding new demand associated with developments and infill projects completed since 2020. (7) Net increase in demand associated with the proposed Foothill Central SPU was applied to start in the 2025 forecast as a conservative planning measure as the likelihood of realizing the full extent of demand associated with the Project is unlikely.
61 9 Conclusion
As summarized in Tables 8.1 through 8.3, the City’s water supplies are sufficient to meet the projected water demands, in addition to the City’s existing and other planned and anticipated future water uses. As noted in Section 8, the surplus supply displayed in Tables 8.1 through 8.3 is a conservative assessment when compared to actual water demand for the City.
9.1 Verification and Approval Process
The City Council must approve this WSA at a regular or special meeting and must be included in the draft Environmental Impact Report being prepared for the proposed Foothill Central SPU.