Streambed Alteration Agreement (1600-2006-0027-R5) Regarding the San Dimas Spreading Grounds Restoration Project


SCH Number
Lead Agency
Fish & Game #5
Document Title
Streambed Alteration Agreement (1600-2006-0027-R5) Regarding the San Dimas Spreading Grounds Restoration Project
Document Type
NOE - Notice of Exemption

Document Description
The Operator proposes to alter the streambed, banks and channel by restoring the spreading grounds basins, earthen channel, and the culverts. The spreading grounds basins, earthen channel and the culverts underneath Romola Avenue were either damaged or washed out by spillway flows from the upstream Puddingstone Diversion Dam during the January 2005 Storm Disaster, including the portion of San Dimas Wash that passes through the basins. The basin levees, earthen channel, and culverts under Romola Avenue need to be repaired and restored. The project will restore water conservation efforts of approximately 1,600 acre-feet per year, emergency (e.g., police, fire) vehicle access from San Dimas Canyon Road to the neighborhood adjacent to the spreading grounds facility, and prevent potential erosion of the channel behind residential property located below the spillway of Puddingstone Diversion Dam. The restoration project at San Dimas Canyon Spreading Grounds will occur in two stages. During the first stage, the four 24-inch CMP culverts beneath Romola Avenue will be extended and the wash regarded to accommodate the passage of low flow beneath Romola Avenue during the 2005-06 storm season. During the second stage of the facility restoration, anticipated to begin in 2007 or 2008, the culverts will be replaced with the same size or larger culverts to ensure the passage of flow. Also, earth-moving equipment will be used within San Dimas Wash to repair the basin levees and earthen channel, to reconfigure the damaged basins, and to create channels to convey water to the basins. Regarding will result in one channel to direct major storm flow and spillway flow and one to two low-flow (less than 50 cfs) channels to convey water to the spreading basins. It is expected that large flows (greater than 2,000 cfs) will wash out the spreading basins. To increase spreading efficiency and reduce maintenance efforts, the basins will be reconfigured within the existing footprint resulting in fewer, larger basins. The exact configuration and number of basins and channels will be determined during the final design. Native material on site and from the upstream San Dimas Sediment Placement Site or Dalton Sediment Placement Site will be used to repair the basin levees. SAA #1600-2006-0027-R5

Contact Information
Naeem Siddiqui
Department of Fish and Game, Region 5
4949 Viewridge Avenue
San Diego, CA 92123

Phone : (562) 493-6897


San Dimas
Los Angeles

Notice of Exemption

Exempt Status
Categorical Exemption
Type, Section or Code
Section 15302
Reasons for Exemption
The project is the reconstruction of an existing structure to its original design configuration (no increase in capacity or change in location), and therefore, it meets the definition of a Class 2 project. No native vegetation shall be impacted by the proposed project.

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 or via phone at (916) 445-0613.

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