City Council
259 N. Wilma Avenue
Ripon, CA 95366
MEMO
To: Honorable City Council
From: Kevin Werner, City Administrator
Date: 05/13/2025
Subject: Woodard & Curran
RECOMMENDED ACTION:
Approve and authorize the Mayor to sign the agreement with Woodard & Curran to prepare the 2025 Wastewater Treatment Plant Facility Plan in the not to exceed amount of $181,985 (funding source: $154,700 allocated to the Wastewater PFFP Capital Fund and $27,285 allocated to the Sewer WWTP Reserve Fund).
BACKGROUND:
The City’s Waste Water Treatment Plant (WWTP) was constructed in the 1970s, with major expansion occurring in the 1990s. The total area covered by the WWTP is roughly 120 acres, with 100 acres occupied by percolation ponds, storage ponds, treatment ponds, or industrial disposal areas, as shown in the figure below.
The City’s WWTP is currently permitted under the State Water Resource Control Board waste discharge requirements (WDR) program since the plant does not discharge to surface waters.
Ripon’s WDR (Order 94-263) originally contained a flow discharge limit of 1.4 MGD, with the ability to increase discharges in the future to 2.34 MGD, pending State Water Resource Control Board approval. The latest permit revision (2008) increased the average discharge rate limit to
1.8 MGD which is where the WWTP currently stands.
The figure below shows the current and projected influent flow to the WWTP as it compares to regulatory limits.
In addition to regulating the maximum discharge rate, the City’s permit regulates water quality limits that must be achieved through the treatment ponds.
Once the Phase 1 Extended Aeration Improvement project is completed, the City’s WWTP treatment capacity will match the regulatory permitted discharge.
At the time the influent flow reaches the regulatory permitted discharge limit, a new WDR order will be issued for the City’s WWTP with more stringent water quality limits that will only be achieved with a more advanced treatment technology than what is currently used by the City.
At the March 3, 2015 City Council Meeting, Council approved the WWTP Facilities Plan prepared by RMC (now Woodard & Curran). This plan provided a guide to a phased approach to capital upgrades, including the estimate of capital cost associated with these treatment technology improvements. These cost estimates were used in the 2017 AB1600 Development Impact Fees Study that established the current City development fees.
The City is required to update its AB1600 Development Impact Fees Study, which are also referred to as PFFP Capital Fees, every eight years. At the April 2025 City Council meeting, the City Council approved a Professional Services Agreement for Goodwin Consulting Group, Inc, to update the City’s AB1600 Development Impact Fees Study.
DISCUSSION/ANALYSIS:
The capital cost related to the WWTP capital improvements is a significant cost that will need to be considered in the upcoming AB1600 Development Impact Fee Study. Staff requested a proposal from Woodard & Curran to assist in updating the 2015 WWTP Report. Their proposed scope of work, as outlined in the attached Exhibit A, includes:
A review of existing treatment and disposal infrastructure to establish a performance baseline;
Updated flows and load projections to align with current and future population trends; A critical review of alternatives identified in the 2015 report, supplemented with additional options where appropriate;
Identification of near-term improvement needs to address capacity, operational, and compliance drivers; and
A refined long-term capital improvement strategy that integrates regulatory outlook, treatment technologies, and disposal feasibility.
This study will also recommend the split in capital cost between new and existing users, which will be not only used as part of the AB1600 Development Impact Fees Study, but also as part of the future sewer rate studies.
FISCAL IMPACT:
The proposed agreement with Woodard & Curran is for a not to exceed amount of $181,985.
This cost will be funded through the Wastewater PFFP Capital Fund ($154,700) and the Sewer WWTP Reserve Fund ($27,285), which have a balance of $6.7 million and $1.9 million, respectively.
Attachments:
1. Agreement_Woodard & Curran
2. Exhibit A_Woodard & Curran