The California Department of Fish and Wildlife (CDFW) has executed Streambed Alteration Agreement number EPIMS-RIV-15087-R6, pursuant to section 1602 of the Fish and Game Code to the Project Applicant, The Metropolitan Water District of Southern California, as represented by Jennifer Harriger.
The Project is associated with impacts to stream habitat related to access road improvements to increase protection of the Colorado River Aqueduct siphons over Work Areas 16, 17, 19, 21, 23, and 24. Access road improvements involve the installation of low-water crossings which will impact desert streams. Existing unpaved roads provide access to each of the Project site locations. The Project realigns segments of the existing unpaved access roads that are located directly on top of or adjacent to structurally vulnerable segments of the siphon. Lowwater crossings will be installed where the realigned access roads cross drainage features. The low water crossings are designed as earthen crossings with approximately 30-inch diameter riprap placed downstream to dissipate energy and reduce erosion. The low-water crossings will require rough grading and excavation to prepare the site for the placement of geotextile fabric and the 30-inch riprap. The riprap will be placed immediately downstream of the low-water crossing. Imported fill material will then be placed upstream of the riprap and graded to ensure adequate grade for the low-water crossing ingress and egress points, as well as match the elevation of the drainage. The riprap and earthen fill material will be sourced from a nearby supplier and imported to the Project sites. Temporary Work Areas have been included around each project site to allow for the ability to maneuver the equipment that will be used to construct the low-water crossings. Vegetation removal within the temporary work area may be required in order to maneuver equipment. No grading, or compaction within the temporary work area is anticipated. Construction crews will avoid established shrubs, as feasible. If avoidance is not practicable, crews will crush vegetation and leave the subsurface root structure intact, as feasible.
The Project will permanently impact 0.61 acres and temporarily impact 1.15 acres of fish and wildlife resources subject to Fish and Game Code section 1600 et. seq. To compensate for these impacts, the Project shall complete one of the following: 1) purchase no less than 0.61 acres of stream habitat re-establishment and 3.56 acres of stream habitat rehabilitation credits through a CDFW-approved mitigation bank within Wester Riverside County, 2) purchase no less than 5.35 acres of ephemeral /intermittent stream preservation credits from The Mojave Desert Tortoise Conservation Bank, Site 6, or 3) acquire, rehabilitate, and perpetually conserve a mitigation site containing no less than 2.98 acres of streambed or riparian habitat within the Whitewater River Watershed.