CONSIDERATION OF DRAFT STAFF REPORT - ADOPT THE 2023 STORMWATER MASTER PLAN IN SUPPORT OF THE ENVISION STOCKTON 2040 GENERAL PLAN UPDATE
RECOMMENDATION
It is recommended that the City Council approve a resolution to adopt the 2023 Stormwater Master Plan prepared in support of the Envision Stockton 2040 General Plan Update.
Summary
The 2023 Stormwater Master Plan (SWMP) supersedes the 2008 Conceptual Storm Drain Master Plan. The 2023 SWMP (Exhibit 1) includes an updated stormwater infrastructure assessment, development of a hydrologic and hydraulic computer model of the City's stormwater system, assessment of system deficiencies for existing and buildout conditions based on the 2040 General Plan Update, identification of infrastructure needs, and development of Capital Improvement Plan (CIP) with cost estimates.
The 2023 SWMP was recommended to Council by the Council Water Committee on February 9, 2023.
By this action, the City Council will adopt the 2023 SWMP to serve as a guiding document for future stormwater infrastructure planning requirements within the City.
DISCUSSION
Background
On November 18, 2008, the City Council adopted the Conceptual Storm Drain Master Plan (SDMP) by Resolution No. 08-0465. This SDMP was prepared to support the 2035 General Plan and served as a planning document to help define and document the specific backbone utility systems required by the Preferred Land Use Alternative of the Stockton 2035 General Plan.
The Envision Stockton 2040 General Plan Update (GPU) was adopted on December 4, 2018, by Resolution No. 2018-12-04-1503-01 and projected different buildout land uses in comparison with the 2035 General Plan. The GPU provided guidance for reevaluating the City's public infrastructure, such as roadways, storm, sewer, and water distribution systems. Utility Master Plan Supplements (UMPS) for water, storm and sanitary sewer services were also prepared in coordination with the Envision Stockton 2040 GPU.
The GPU action also certified the Environmental Impact Report (EIR), Findings of Fact, and Mitigation Monitoring and Reporting Program for the Envision Stockton 2040 GPU and the UMPS.
In conjunction with the Envision Stockton 2040 GPU, the City identified future development areas that are both within existing City Limits and outside of City Limits via the April 2020 Sphere of Influence/Municipal Service Review (SOI/MSR). The City Council adopted the SOI/MSR on July 14, 2020 by Resolution No. 2020-07-14-1103.
The Envision Stockton 2040 GPU and the SOI/MSR provide near-term and future development projections used in the preparation and analysis of all Utility Master Plans.
On June 9, 2020, a Professional Services Contract was awarded to Hazen and Sawyer, Inc. (H&S) for the preparation of the Stormwater Master Plan (SWMP). The SWMP updates the infrastructure inventory, assesses system deficiencies for existing and buildout conditions based on the 2040 General Plan, develops a hydrologic and hydraulic computer model of the City's Stormwater System, identifies infrastructure needs, and develops CIP projects with cost estimates.
Present Situation
The primary purpose of the 2023 SWMP is to identify the extent and nature of stormwater flooding under existing and future conditions and develop CIP projects that MUD could implement to alleviate stormwater flooding and support future development in the City.
Hazen and Sawyer utilized PC-Stormwater Management Model (PC-SWMM) software to analyze and model the hydrology and hydraulics of the City's stormwater infrastructure. The modeling efforts focused on the 10-year, 24-hour storm event, consistent with City standards. Other flood protection and levee maintenance agencies, including the San Joaquin Area Flood Control Agency, San Joaquin County Channel Maintenance & Zone 9 and local reclamation districts typically develop infrastructure to help manage larger flood events, such as the 100 or 200-year floods, through levee and channel maintenance and improvement projects.
The focus of this 2023 SWMP was urban stormwater conveyance infrastructure like catch basins, pipelines, and pump stations. The modeling efforts analyzed the existing conditions and future anticipated development, the locations of which were established and prioritized in coordination with MUD staff and other City stakeholders via an Online Stakeholder Input Survey and subsequent discussions.
Hazen and Sawyer developed improvement concepts grouped into high, medium, and low-priority categories based on stakeholders' input and coordination efforts. The improvement projects ranged in cost from under $5 Million to over $75 Million. In addition to these large projects, opportunities exist to address smaller-scale drainage deficiencies and maintenance needs throughout the City, such as pump station rehabilitation and undersized pipe and catch basin replacement projects.
The financial team also assessed MUD baseline financials, which indicated expenditures are projected to increase and that current stormwater utility revenues are inadequate. The assessment only considered operational costs and excluded the identified CIP projects.
It was recommended that the City and MUD, concurrent with the adoption of the 2023 SWMP, start efforts to conduct an effective educational outreach program and implement an updated assessment strategy to generate a reliable and predictable revenue source sufficient for MUD stormwater operations and capital costs of the high and medium-priority projects.
The team also recommended that the City leverage the availability of Federal and State grants and low-cost loans to help pay for the CIP projects.
All development impact fees/connection fees, including stormwater connection fees, are currently under review through a separate City effort led by the Community Development Department.
On February 9, 2023, the 2023 SWMP was presented to the Council Water Committee and received a recommendation to forward the 2023 SWMP to Council for consideration and adoption.
It is recommended that the City Council adopt the 2023 Stormwater Master Plan in concurrence with the Envision Stockton 2040 General Plan Update.
FINANCIAL SUMMARY
There is no impact on the City's General Fund or any other unrestricted fund from this action.
DRAFT STAFF REPORT ATTACHMENT A