City Council
259 N. Wilma Avenue
Ripon, CA 95366
MEMO
To: Honorable City Council
From: James Pease, Public Works Director
Date: 06/09/2026
Subject: Professional Services Agreement - WaterSolve LLC RECOMMENDED ACTION:
Approve and authorize the Mayor to sign the Professional Services Agreement with WaterSolve LLC to survey the Wastewater Treatment Ponds for sludge content and provide a report of findings in the not to exceed amount of $19,600 (funding source: Sewer Enterprise Capital 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.
At the May 13, 2025 City Council Meeting, Council approved the WWTP Facility Plan Update to be prepared Woodard & Curran. The finalized plan will provide a guide to a phased approach for capital upgrades, including the estimate of capital cost associated with these treatment technology improvements. These cost estimates will be used in the upcoming AB1600 Development Impact Fees Study that establishes the City development fees which is currently underway.
DISCUSSION:
The WWTP Facility Plan Update is nearing completion, and City staff is currently reviewing and providing comments on the final draft. The plan identifies a reduction in available treatment pond volume resulting from the accumulation of sludge over time, which has adversely affected treatment capacity and operational efficiency.
A critical first step in addressing this issue is to complete a comprehensive sludge survey of the City's four treatment ponds to accurately quantify the volume and distribution of accumulated sludge. This information is essential because the costs associated with dredging, hauling, and disposal can vary significantly depending on the volume and characteristics of the material present. In addition to supporting project cost development, the survey results will provide staff with information regarding sludge accumulation patterns and available treatment capacity, allowing for the evaluation of operational improvements to enhance treatment performance and overall plant efficiency.
Staff solicited and received three proposals to perform a comprehensive sludge survey and sampling assessment of the City's four wastewater treatment ponds. WaterSolve LLC was determined to be the lowest responsive and responsible firm. WaterSolve LLC has extensive experience conducting similar wastewater treatment pond evaluations and has successfully completed several comparable projects. Exhibit A of the attached Professional Services Agreement outlines the scope of services to be provided by WaterSolve LLC.
FISCAL IMPACT:
The attached Professional Services Agreement with WaterSolve LLC to complete the sludge survey, sampling, analysis, and reporting services are for a total amount not to exceed $19,600 and will be funded by the Sewer Enterprise Capital Fund.
Attachments:
1. WWTP Lagoon Sludge Survey PSA - WaterSolve LLC