City of Gonzales
COMMUNITY DEVELOPMENT DEPARTMENT
STAFF REPORT
TO: Honorable Mayor Rios and City Council
DATE: February 21, 2023
FROM: Taven Kinison Brown, Community Development Director THROUGH: Trevin Barber, City Manager
SUBJECT: Water Supply Assessment for Vista Lucia Specific Plan
RECOMMENDATION
Staff recommends that the City Council:
• Receive a presentation of the Water Supply Assessment for the Vista Lucia Specific Plan. • Acknowledge that the Water Supply Assessment will be used to inform environmental review for the Vista Lucia Specific Plan Project and may be used as an informational foundation for other development projects under review, including the Rianda Family Cooler Project, the Puente Del Monte Specific Plan, the development of the D’Arrigo 138 acres within City Limits east of Hwy 101, and future buildout of the Gonzales Agricultural Industrial Park.
BACKGROUND
As the City approached its 2010 General Plan update and later negotiated an expansion of the City’s Sphere of Influence to include the Vista Lucia Specific Plan (VLSP), the Puente Del Monte Specific Plan (PDMSP) proposal and various parcels owned by D’Arrigo Bros, it was wholly apparent that there is adequate water available to serve the projects.
The Water Supply Law (Water Code Section 10910 et seq.) also known as SB610 requires that subdivisions greater than 500 units be analyzed for sufficiency of water supplies over a 20 year horizon that includes existing and proposed uses during that horizon. The WSA must also analyze “dry” years in addition to normal or average conditions. SB610 requires the City of Gonzales to prepare a WSA for the VLSP project. The City operates a public water system that serves customers within its current City AGENDA
ITEM
2 limits; and will also serve the areas to be annexed into the City.
In the spring and summer of 2022, it became known to the City that the Puente Del Monte Specific Plan property-owner’s group of Jackson Family Investments and the Rianda Family Trust, had separated their once unified approach to the PDM Specific Plan development, to now include an agriculture processing cooler facility on the 107-acre portion of the plan area owned by the Rianda Family Trust. This change in affairs affected the scope and focus of the Water Supply Assessment, in that the cooler would have a different water use than the residentially focused Puente Del Monte Specific Plan. Additionally, it became apparent that Jackson Family Investments would be waiting for a period of time to see how the cooler project would fare through the City and LAFCo exercises before committing to a redesign or reorganization of the Specific Plan areas anticipated for development on the remaining Jackson Family Investment properties. The “Project” now is the Vista Lucia Specific Plan community. Future development projects may build upon the information presented in the WSA.
The WSA report has been prepared by Zanjero Consulting, under contract to the Pembrook Development team behind the Vista Lucia Specific Plan effort. The report was reviewed by the City’s engineering consultant, Schaaf & Wheeler the City of Gonzales Community Development Director and Public Works Director.
Representatives with Zanjero and Schaaf & Wheeler will be present or available online to speak to technical or detailed questions should the Commission and Council have questions.
REVIEW AND ANALYSIS
Please refer to the attached Administrative Draft of the Water Supply Assessment for the Vista Lucia Specific Plan Area for full details. The report is organized according to the following sections named below:
• Project Introduction
• Proposed Project Estimated Water Demands
• Estimated Water Demands for Existing City Customers and Other Planned Uses • Water Supply Characterization
• Sufficiency Analysis & Conclusions
Project Introduction
As described in more detail in the Vista Lucia Specific Plan, the Proposed Project plans for 3,498 dwelling units, with 995 designated low density, 1,239 designated medium density, 540 designated as medium-high density, 620 designated as high density, and 104 designated as mixed-use The Proposed Project anticipates 57 acres of neighborhood and community parks, 20 acres designated as promenades, 2 acres designated as neighborhood greens, 73 acres dedicated to stormwater detention, and 42 acres for schools.
For purposes of this WSA, the Proposed Project anticipates all land uses to be completed by 2050 to allow the analysis to fully evaluate the complete project. Consistent with the City’s projections, the Proposed Project is anticipated to be completed within 30 years. The specifics and timing of the later phases will be determined by market conditions.
Proposed Project Estimated Water Demands.
The VLSP community is anticipated to require approximately 1,501 acre-feet of water each year at full build-out. This demand is summarized below:
Table 2-6. Summary of proposed Project Water Use
Proposed Project
Acre-Feet per Year at Full Buildout
Indoor Outdoor Misc. Subtotal Loss Factor Grand Total
Vista Lucia Residential 901 283 - 1,351 150 1,501
Non-Residential 36 131
Table 2-7: Proposed Project Water Demands under Dry-Year Conditions Multiple Dry Year
Normal Single Dry Year 1 Year 2 Year 3-5
% Increase (reduction) 0% 5% 5% 0% -10%
Resulting Change in Demand (af/yr) 0 75 75 0 -150
Total Demand (af/yr) 1,501 1,576 1,576 1,501 1,351
The Proposed Project will be constructed on a 768-acre site currently used for the farming of crops irrigated with groundwater. The current water consumption of the Proposed Project site was from 2016 – 2021, to be approximately 1,900 – 2,000 acre-feet a year.
The Proposed Project is expected to require 1,375 acre-feet per year under normal conditions, with only 297 acre-feet per year of that demand used outdoors (and therefore most likely to evaporate rather than be captured by the City’s wastewater collection system, see Sections 3, 4, and 5). This analysis demonstrates that the Proposed Project is expected to generate significantly less consumptive demand for groundwater than the site’s current agricultural land use.
Estimated Water Demands for Existing City Customers and Other Planned Uses Water use data from the most recent 5 years, from 2016 to 2021, provided the primary basis for analyzing current water use trends. In 2021, the most recent year for which data is available, the City of Gonzales served 1,958 service connections, all of which are metered. Of these connections, 1,599 were singlefamily residential, 176 were multi-family residential, 132 were commercial or institutional, 39 were industrial, and 12 were landscaping.
In addition to serving the Proposed Project, as described in Section 2, the City of Gonzales will continue to serve its existing customers and will extend water service to other planned developments (Puente Del Monte, Rianda Cooler, D’Arrigo, and Franscioni). Including all anticipated residential and non-residential indoor and outdoor water demands plus non-revenue water, the existing City and other planned developments are expected to generate 4,992 acre-feet of water demand annually at full buildout. These demands are summarized in Table 3-9. Summary of Existing City and Other Planned Development Water Demand.
Water Supply Characterization
Many existing water users, including the existing customers of the City of Gonzales and existing irrigated agriculture on the site of the Proposed Project, share groundwater available in the aquifer beneath the Proposed Project. This section provides a detailed characterization of the aquifer, as well as historic and projected uses of this shared resource. Section 5 details the sufficiency of groundwater resources to meet the long-term needs of the Proposed Project.
The Proposed Project is located near the intersection of three subbasins: the 180/400-Foot Aquifer Subbasin (Basin No. 3-004.01), the Eastside Subbasin (Basin No. 3-004.02), and the Forebay Subbasin (Basin No. 3-004.04), as defined by DWR Bulletin 118.1 The subbasins cover areas of 140 square miles, 90 square miles, and 147 square miles respectively.
1 California Department of Water Resources, California’s Groundwater Update 2020 Highlights (2020).
City of Gonzales Sustainable Yield
The City of Gonzales straddles the intersection of the three subbasins described above, which somewhat complicates the consideration the City’s future water use in each subbasins’ GSP. However, the three GSPs are all consistent in their approach to municipal water use in future water budgets, which were the basis for calculating the sustainable yield values presented in this WSA. All three subbasins’ GSPs state that, “Because the [groundwater] model assumes no urban growth, future municipal pumping was assumed to be equal to current municipal pumping. Future agricultural pumping is then calculated as the total projected pumping minus the current municipal pumping.” As calculated in Section 3.1 of this WSA, current pumping by the City of Gonzales is 1,910 acre-feet per year and the net consumption of groundwater after accounting for recharge is 874 acre-feet per year.
For the purposes of this WSA, it is assumed that 874 acre-feet of net water consumption by the City of Gonzales (2020-2021 average) represents the best available estimate of the long-term net consumption by the City accounted for in GSP future water budgets. Therefore, 874 acre-feet per year is considered an available consumptive supply to the existing City customers for the purposes of the sufficiency analysis presented in Section 5.
Sustainable Yield Conclusions
The Proposed Project will be supplied by the City of Gonzales, which is in turn supplied by groundwater from the Salinas Valley Groundwater Basin. While all of the City’s existing wells are located in either the Eastside or the 180/400-Foot Aquifer Subbasin, the City could conceivably pump water from any of the three groundwater subbasins underlying Gonzales to serve its existing customers, the Proposed Project, and other planned uses. As described above, this WSA used the sustainable yields calculated by the three subbasins’ GSPs as the basis to calculate the water supply available to the existing City, the Proposed Project, and the City’s other planned developments.
The average sustainable yield of the three subbasins would be 1.60 acre-feet/acre/year. As a conservative assumption, this WSA assumes that the most restrictive subbasin’s sustainable yield estimate will limit the groundwater supply available to the proposed project. Therefore, the sustainable yield of 1.37 acrefeet/acre/year for consumptive water use calculated for 180/400-Foot Aquifer Subbasin is assumed to represent the water supply available to the Proposed Project and the City of Gonzales’ other planned developments on a per acre basis. The water use of the existing City of Gonzales has already been accounted for as an “Urban Use” in the various Subbasins’ water budgets.
The sustainable yield of 1.37 acre-feet/acre/year for consumptive water use can then be multiplied by the number of acres in the Proposed Project and the City’s other planned developments to arrive at the total quantity of water available as consumptive supply. These calculations are presented in Table 4-2. With a total acreage of 2,239, the total sustainable consumptive groundwater supply available to the Proposed Project and the City of Gonzales’ other planned developments is 3,072 acre-feet per year. In addition, the City of Gonzales was estimated to have had a current net consumption of 874 acre-feet of groundwater, which the GSPs assume will be constant throughout the planning period. The City’s current consumption is a static value not scaled by acres. The grand total supply of sustainable yield for net consumption is estimated to be 3,946 acre-feet/year, as presented in Table 4-2.
The report continues and describes Water Rights, Financing and Regulatory Approvals Sufficiency Analysis & Conclusions
As illustrated in Figure 5-1, the total net consumptive use of the Proposed Project, Existing City, and other planned developments is 2,398 acre-feet per year. The sustainable yield available to serve these uses is 3,946 acre-feet per year. Therefore, this WSA finds that there is sufficient groundwater available to sustainably supply the Proposed Project, Existing City, and other planned uses.
As detailed in this WSA, sufficient groundwater resources exist to meet the forecast demand of the Proposed Project as described in Section 1. While approximately 6,493 acre-feet of groundwater pumping will be required to meet the combined total demand of the existing City, the Proposed Project, and other planned developments, the net consumptive use is only approximately 2,398 acre-feet. This value represents the amount of groundwater extracted that will primarily leave the basin through evapotranspiration and evaporation.
Also, during single and multiple dry years, the total combined demands are expected to increase extraction to as much as 6,818 acre-feet as a result of increased demand for irrigation water, but also decrease to as low as 5,844 acre-feet when temporary shortage provisions are instituted. Net consumptive use is expected to increase and decrease by equal proportions during single and multiple dry years but will remain well below the available sustainable yield.
Potential Uses of the Water Supply Assessment.
The Water Supply Assessment will be used to inform environmental review for the Vista Lucia Specific Plan Project, and may be used as an informational foundation for other development projects under review, including the Rianda Family Cooler Project on Gloria Road, the Puente Del Monte Specific Plan effort as it may be modified by the Rianda Cooler Project, the development of the D’Arrigo 138 acres within City Limits east of Hwy 101, and future buildout of the Gonzales Agricultural Industrial Park.
Explain the Recommendation and How it Supports the Vision Gonzales will continue to be a safe, clean, family-friendly community, diverse in its heritage, and committed to working collaboratively to preserve and retain its small-town charm.
Explanation:
The City has planned to grow into the Sphere of Influence areas east of the City of Gonzales as negotiated with the County of Monterey in 2014 through a Memorandum of Agreement. The City will guide development to be consistent with its General Plan and its Vision and will assure that infrastructure and utility systems, such as the provision of municipal water and delivery systems will be in place to serve the new development in a cost effective, revenue neutral manner. Review and acceptance of the reporting included in this Vista Lucia Specific Plan Water Supply Assessment report acknowledges that sufficient ground water is present in the underlying aquifers, and that the conversion of these particular agricultural lands will use less water than historical or present agricultural practices.
Explain how the Recommendation Directly Implements the Mission The City Council and staff of the City of Gonzales will realize our Vision by providing the leadership, commitment, and resources necessary to provide excellent services that enhance the quality of life of our diverse community.
Explanation: As above, the City will guide development to be consistent with its General Plan and its Vision and will assure that infrastructure and utility systems, such as the provision of municipal water and delivery systems will be in place to serve the new development in a cost effective, revenue neutral manner.
City services will be delivered in a cost-effective, respectful, and friendly manner to ensure the safety and well-being of the residents and the promotion of business, recreational, housing and employment opportunities in an environmentally sustainable manner.
Explanation: As above, the City will guide development to be consistent with its General Plan and its Vision and will assure that infrastructure and utility systems, such as the provision of municipal water and delivery systems will be in place to serve the new development in a cost effective, revenue neutral manner. Additionally, financing systems and cost recovery through property assessments or district levies (or other mechanisms) for services to be provided into the new neighborhoods, including water service in the eventual Vista Lucia Specific Plan area, will assure that no greater financial burden will fall on existing city residents through approval of new developments and residential neighborhoods as contemplated and forecast in the VLSP Water Supply Assessment.
Strong fiscal policies allow us to provide appropriate infrastructure for:
• Public Safety X Yes No N/A
• Housing X Yes No N/A
• Recreation X Yes No N/A
• Environment X Yes No N/A
• Education X Yes No N/A
ALTERNATIVES
• Receive a presentation of the Administrative Draft of the Water Supply Assessment for the Vista Lucia Specific Plan Area (VLSP SWA). And / Or:
• Request additional information or direct refinement to the Water Supply Assessment, which would continue the matter to a date certain or uncertain.
BUDGET IMPACT
The preparation of the Water Supply Assessment for the Vista Lucia Specific Plan Project has been paid for by Pembrook Development. City of Gonzales staff time and city consultant and peer reviews have been paid for through Reimbursement Agreements with the Pembrook Development. Invoices are billed against the developer’s deposit so that no impact on city budget results.
CONCLUSION
Staff recommends the City Council:
• Receive a presentation of the Water Supply Assessment for the Vista Lucia Specific Plan. • Acknowledge that the Water Supply Assessment will be used to inform environmental review for the Vista Lucia Specific Plan Project and may be used as an informational foundation for other development projects under review, including the Rianda Family Cooler Project, the Puente Del Monte Specific Plan effort, the development of the D’Arrigo 138 acres within City Limits east of Hwy 101, and future buildout of the Gonzales Agricultural Industrial Park.
Attachments:
1. Vista Lucia WSA (Public Review Draft)
2. WSA - Appendix A
3. WSA - Appendix B