Arsenic Treatment Facility Project at Laurel Water Treatment Plant
Summary
SCH Number
2025010320
Public Agency
Stinson Beach County Water District
Document Title
Arsenic Treatment Facility Project at Laurel Water Treatment Plant
Document Type
NOE - Notice of Exemption
Received
Posted
1/10/2025
Document Description
Stinson Water obtained an emergency Small Community Drought Relief Grant in late 2021 to address low water levels during that year’s drought. In March of 2022, a new well was drilled at Stinson Water’s existing Ranch Tank Well site to replace an old, failing well, and to maintain operational flexibility and reliability of existing water supply sources to mitigate low water levels during future droughts. Upon performing water quality testing on the new well, arsenic levels in some of the well water samples were above the maximum contaminant level (“MCL”).
Multiple arsenic treatment methods were evaluated and plans for locating the treatment equipment were investigated. Stinson Water ultimately decided to pursue a plan to procure and install an arsenic treatment system to be centrally located at its Laurel WTP site. In addition to treating the water from the new Ranch Tank Well for arsenic, locating the proposed treatment equipment at the existing Laurel WTP site will allow Stinson Water to treat water from all of its water sources for arsenic (some of Stinson Water’s other sources contain lesser amounts of arsenic below the MCL). The proposed treatment equipment under consideration will utilize two (2) pressure vessels (72 inch diameter x 66 inch high) filled with a media that will remove or significantly reduce arsenic from the raw sources to levels well below the MCL. The treatment equipment under consideration will produce treated water at a rate of 200 gallons per minute (“gpm”).
The project will have a small footprint and will be installed in the WTP’s existing gravel parking lot. The project site consists of a 375 square foot area of the parking lot that currently houses a backhoe and a steel storage container (see Photo 1, Photo 2, and Photo 3). The concrete pad that the equipment will sit on will be poured on top of the gravel parking area. There will be no disturbance of the environment surrounding the WTP.
Contact Information
Name
Kent Nelson
Agency Name
Stinson Beach County Water District
Job Title
General Manager
Contact Types
Lead/Public Agency / Project Applicant
Phone
Email
Name
Allan Richards
Agency Name
Stetson Engineers
Job Title
Principal
Contact Types
Project Applicant / Parties Undertaking Project
Phone
Location
Cities
Stinson Beach
Counties
Marin
Regions
Southern California
Cross Streets
Buena Vista Ave
Zip
94970
Parcel #
195-260-48
Notice of Exemption
Exempt Status
Categorical Exemption
Type, Section or Code
Title 14, Division 6, Chapter 3, Section 15303
Reasons for Exemption
Section 15303(d) states that “Water main, sewage, electrical, gas, and other utility extensions, including street improvements, of reasonable length to serve such construction” are eligible for exemption. The proposed project will be an extension of Stinson Water’s existing water treatment facilities and take up a small amount of space. Because of limited space in the main water treatment plant building, the new facilities will be located slightly downhill from the rest of the facilities, but still on Stinson Water’s property.
Exempt Status
Emergency Project
Type, Section or Code
Sec. 21080(b)(4); 15269(b)(c)
Reasons for Exemption
This exemption is appropriate for the proposed Project given the potential for severe future droughts and wildfire seasons. The need for potable water from the new Ranch well is urgent because future drought conditions may (as during previous droughts) significantly reduce surface water resources that the District uses in conjunction with well water to provide safe and reliable drinking water to the community of Stinson Beach. The Project is consistent with the example provided in 15269 (b), as the use of the water originating from the newly drilled is necessary to address the anticipated emergency of the northern California wildfires and ongoing drought.
County Clerk
Marin
Attachments
Notice of Exemption
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