Middle Green Valley Development Project (Lake or Streambed Alteration Agreement No. EPIMSSOL-34638-R3)
12 Documents in Project
Summary
SCH Number
2009062048
Lead Agency
Solano County
Document Title
Middle Green Valley Development Project (Lake or Streambed Alteration Agreement No. EPIMSSOL-34638-R3)
Document Type
NOD - Notice of Determination
Received
Posted
6/26/2024
Document Description
The Project is limited to two sites where new outfalls and rock slope protection (RSP) will be installed in Green
Valley Creek:
At site 1, Mason Road Crossing, there are two existing earthen outfalls on the upstream and downstream sides of
Mason Road Bridge. Mason Road will be widened in this area, and to accommodate this widening the existing
outfalls will be reestablished and upgraded by armoring the banks of Green Valley Creek with RSP aprons (Exhibit
A).
The upstream outfall will consist of a trapezoidal area approximately 66.5 feet long and 12 feet wide, covering an
area of 781 square feet. This area will be excavated to a depth of 18 inches, and filled with 9-inch diameter Class II
angular rip-rap. The outfall will extend from a proposed roadside ditch to the thalweg of Green Valley Creek. The
outfall will drop into Green Valley Creek at a 6:1 slope, and will have a center one foot lower than the outer edges.
The downstream outfall will consist of a trapezoidal area approximately 103 feet long and 12 feet wide, covering an
area of 1,219 square feet. This area will be excavated to a depth of 18 inches, and filled with 9-inch diameter Class
II angular rip-rap. The outfall will extend from a proposed roadside ditch to the thalweg of Green Valley Creek. The
outfall will drop into Green Valley Creek at a 6:1 slope, and will have a center one foot lower than the outer edges.
At site 2, a trapezoidal area approximately 16 feet long and 18 feet wide, covering an area of 266.9 square feet will
be excavated to a depth of 18 inches, and filled with 9-inch diameter Class II angular rip-rap (Exhibit B). The rip-rap
will surround a 48-inch high density polyethylene or polymer-coated steel pipe conveying water from a proposed
stormwater detention basin.
Temporary cofferdams made of sandbags surrounded by polyethylene plastic sheeting will be installed at both
sites. These cofferdams will be constructed to dewater the western portion of Green Valley Creek while conveying
water downstream through the eastern portion.
The Project will result in permanent impacts to 2,266.9 square feet and 40 linear feet of stream and riparian habitat;
and temporary impacts to approximately 4,450 square feet and 102 linear feet of stream and riparian habitat.
Contact Information
Name
Alexander Single
Agency Name
CDFW
Job Title
Environmental Scientist
Contact Types
Responsible Agency
Phone
Location
Cities
Fairfield
Counties
Solano
Regions
Northern California, San Francisco Bay Area
Other Location Info
1. Site one, Mason Road Crossing, is located at Latitude 38.23601 °N, Longitude -122.15590 °W; the
northeast ¼ of the southeast ¼ of Section 35, Township 5 North, Range 3 West of the Mount Diablo Base
Range and Meridian; U.S. Geological Survey Cordelia 7.5-minute quadrangle.
2. Site two, Stormwater Detention Basin Outfall, is located at Latitude 38.22795 °N, Longitude -122.15200
°W; the northeast ¼ of the northeast ¼ of Section 1, Township 4 North, Range 3 West of the Mount Diablo
Base Range and Meridian; U.S. Geological Survey Cordelia 7.5-minute quadrangle.
Notice of Determination
Approving Agency
CDFW
Approving Agency Role
Responsible Agency
Approved On
County Clerk
Solano
Final Environmental Document Available at
2825 Cordelia Road, Suite 100
Fairfield, CA 94534
Determinations
(1) The project will have a significant impact on the environment
No
(2a) An Environmental Impact Report was prepared for this project pursuant to the provisions of CEQA
Yes
(2b) A Mitigated or a Negative Declaration was prepared for this project pursuant to the provisions of CEQA
No
(2c) An other document type was prepared for this project pursuant to the provisions of CEQA
No
(3) Mitigated measures were made a condition of the approval of the project
Yes
(4) A mitigation reporting or monitoring plan was adopted for this project
Yes
(5) A Statement of Overriding Considerations was adopted for this project
No
(6) Findings were made pursuant to the provisions of CEQA
Yes
Attachments
Notice of Determination
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