L.L. Anderson Dam Spillway Modification Project
3 Documents in Project
Summary
SCH Number
2008052096
Lead Agency
Placer County Water Agency
Document Title
L.L. Anderson Dam Spillway Modification Project
Document Type
NOD - Notice of Determination
Received
Posted
7/7/2008
Present Land Use
Project area zoned: Timberland; Surrounding areas zoned Agriculture, Resource Protection, Rural Residential, Timberland, Urban Uses (1994)
Document Description
The presently proposed project involves widening the existing spillway at L.L. Anderson Dam and replacing and raising the dam crest parapet wall to pass the PMF. The spillway crest would need to be widened 32 feet to maintain the peak reservoir stage at El. 5,273 feet during the general-storm PMF. The spillway widening would be achieved by rock excavation with blasting and machinery, construction of new spillway structure, seepage cutoff through grouting of new spillway structure rock foundation, rock bolting and shotcrete, re-establishing automatic control system to the existing power adjacent to the new spillway structure, demolition of the existing spillway structure, and placement of excavated rock spoil against downstream face of the dam. The existing spillway structure would also serve as a temporary (seasonal) cofferdam in the spillway during construction before it is demolished. Parapet wall replacement would be achieved by closing a portion of one lane on the dam crest, demolishing the existing parapet wall, excavating into the dam crest, forming, reinforcing, and installing a new reinforced concrete wall. In addition, due to a camber in the crest height across the dam profile, approximately 1,000 feet of the dam crest pavement will be removed and raised with aggregate base and new pavement to achieve a uniform road elevation of 5,273 feet or greater.
Contact Information
Name
Jon Mattson
Agency Name
Placer County Water Agency
Contact Types
Lead/Public Agency
Address
Phone
Location
Coordinates
Counties
Placer
Zip
95631
Total Acres
15
Parcel #
067-160-104-510
Waterways
Middle Fork American River
Township
15N
Range
13E
Section
36
Other Location Info
Foresthill
Notice of Determination
Approving Agency
Placer County Water Agency
Approving Agency Role
Lead Agency
Approved On
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
No
(2b) A Mitigated or a Negative Declaration was prepared for this project pursuant to the provisions of CEQA
Yes
(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
N/A
(5) A Statement of Overriding Considerations was adopted for this project
No
(6) Findings were made pursuant to the provisions of CEQA
No
Disclaimer: The document was originally posted before CEQAnet had the capability to host attachments for the public. To obtain the original attachments for this document, please contact the lead agency at the contact information listed above. You may also contact the OPR via email at state.clearinghouse@opr.ca.gov or via phone at (916) 445-0613.