Old and Middle River Pump Stations Water Quality Monitoring Instrumentation Improvements Project
Summary
SCH Number
2026060634
Public Agency
Contra Costa Water District
Document Title
Old and Middle River Pump Stations Water Quality Monitoring Instrumentation Improvements Project
Document Type
NOE - Notice of Exemption
Received
Posted
6/12/2026
Document Description
This Project consists of the installation of upgraded water quality monitoring equipment at CCWD’s Old River and Middle River intakes in the Sacramento-San Joquin Delta. Currently, water samples at these intakes are pumped out of wet wells that pass through two-inch diameter piping, which is at high risk of being blocked by the spread of invasive golden mussels (Limnoperna fortunei). The purpose of this project is to install new water quality monitoring equipment that will provide more reliable monitoring data and will decrease the risk of being blocked by golden mussels. A total of two multiparameter sondes will be installed, one at Old River and one at Middle River. Each sonde will be incased in a six-inch diameter HDPE pipe stilling well and mounted to the existing concrete cantilever platforms located in front of the fish screen at each intake, where they will extend into the water to collect water quality data. These larger diameter stilling wells will significantly decrease the risk of clogging due to golden mussels and will be easier to access and maintain. See Figure 1 for a Project vicinity map and Figures 2 and 3 for Project location maps. Data from these sondes will be transmitted back to the electrical building at each site through new and existing conduits.
The Project is expected to take three months, with construction occurring between June and August of 2026. Equipment laydown and vehicle staging will occur in previously disturbed areas, such as paved roads and parking areas, within the boundaries of the pump stations on CCWD property. The following types of equipment are expected to be present at the project site: crew trucks, a boat or barge, and power tools.
Project activities will occur in previously developed and disturbed areas on CCWD property. No vegetation removal or tree removal will occur. No ground disturbance will occur, and there will be no impact to the banks or beds of the rivers at either intake. Equipment installation will occur from land via the concrete cantilever platforms and from a boat or barge in the water immediately below the platform. The Project is not anticipated to adversely affect natural resources or areas of known cultural or historic resources.
Contact Information
Name
Cody Ericksen
Agency Name
Contra Costa Water District
Job Title
Associate Planner
Contact Types
Lead/Public Agency / Project Applicant / Parties Undertaking Project
Address
Phone
Email
Location
Cities
unincorporated areas of both counties
Counties
Contra Costa, San Joaquin
Regions
Countywide, Unincorporated
State Highways
SR 4
Waterways
Old River, Middle River, Indian Slough, North Victoria Canal, Italian Slough
Other Location Info
The Old River and Middle River Pump Stations Water Quality Monitoring Instrumentation Improvements Project (Project) is located at Contra Costa Water District's (CCWD) Old River Pump Station at 17521 CA-4, Discovery Bay, CA, 94505, and Middle River Pump Station at 18520 W State Route 4, Stockton, CA, 95220.
Notice of Exemption
Exempt Status
Categorical Exemption
Type, Section or Code
Class 1, Section 15301(b)
Reasons for Exemption
This project is exempt as it involves the repair and maintenance of an existing facility owned by a public utility.
Exempt Status
Categorical Exemption
Type, Section or Code
Class 6, Section 15306
Reasons for Exemption
This project is exempt as it involves basic data collection which will not result in major disturbance to an environmental resource.
County Clerks
Contra Costa, San Joaquin
Attachments
Notice of Exemption
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