Garden Gulch Creek Tributary Pond and Culvert Project (Streambed Alteration Agreement No. 1600- 2018-0807-R1I)

Garden Gulch Creek Tributary Pond and Culvert Project (Streambed Alteration Agreement No. 1600- 2018-0807-R1I)

The California Department of Fish and Wildlife (CDFW) has executed Streambed Alteration Agreement (1600-2018-0807-R1I), pursuant to Fish and Game Code section 1602, to the project Applicant, Gas for Less LLC, as represented by Brian Donnell. The project consists of four stream crossing upgrades on an unnamed tributary to Garden Gulch Creek and spillway improvements to an existing on-stream impoundment. The scope of work required at each location is summarized below. Stream Crossing #1: The existing crossing consists of an undersized 18-inch corrugated metal pipe (CMP) culvert on an ephemeral stream. The existing CMP culvert will be removed and replaced with a 30-inch CMP culvert. The replacement will require excavation of approximately 12 yards of earthen fill. The inlet and outlet will be armored with approximately five cubic yards (cy) of 6-inch to 12-inch diameter rock. A critical dip consisting of 4-inch to 6- inch diameter sharp angular rock will be installed five feet from culvert centerline on both sides. The road prism will be rocked for 50 feet from culvert centerline with crushed road base to reduce surface erosion. The culvert replacement and road surface improvements will require approximately 1,235 square feet (sq ft) of total ground disturbance. No permanent vegetation removal is required at this location. Stream Crossing #2: The existing crossing consists of an undersized 8-inch CMP culvert on an ephemeral stream. The culvert will be removed and replaced with a rocked ford, armored with angular rock which will be sized appropriately to resist washout. The road prism will be rocked for 50 feet from culvert centerline with crushed road base to reduce surface erosion. The CMP removal will require excavation of approximately 12 cy of earthen fill, and the entirety of the crossing improvement will require approximately 1,235 sq ft of ground disturbance. No permanent vegetation removal is required at this location. Stream Crossing #3: The existing crossing consists of an undersized 18-inch diameter CMP on an intermittent stream, directly below a pond. The culvert will be removed and replaced with a rocked ford, armored with angular rock which will be sized appropriately to resist washout. The road prism will be rocked for 50 feet from culvert centerline with crushed road base to reduce surface erosion. The CMP removal will require excavation of approximately 9 cy of earthen fill, and the entirety of the crossing improvement will require approximately 800 sq ft of ground disturbance. A clear water diversion may be required for construction if flowing water is present during construction. No permanent vegetation removal is required at this location. Stream Crossing #4: The existing crossing consists of an undersized and misaligned 24-inch diameter CMP on an intermittent stream, directly above a pond. The culvert will be removed and replaced with a rocked ford, armored with angular rock which will be sized appropriately to resist washout. The road prism will be rocked for 50 feet from culvert centerline with crushed road base to reduce surface erosion. The CMP removal will require excavation of approximately 27 cy of earthen fill, and the entirety of the crossing improvement will require approximately 2,450 sq ft of ground disturbance. A clear water diversion may be required for construction if flowing water is present during construction. The culvert removal and ford installation will require the permanent loss of one ponderosa pine, two alders, and one black oak. Impoundment Spillway Improvement: An existing 0.32-acre onstream impoundment requires improvements to the overflow/spillway. The current spillway is 15 feet wide by 12 feet in length, comprised of a failing concrete apron and rock slope protection (RSP). The proposed improvement includes installation of a larger RSP spillway approximately 13 feet wide and 170 feet long. The new spillway installation will require excavation of approximately 197 cy of earthen fill, placement of approximately 91.5 cy of RSP underlain with woven geotextile liner. The spillway improvement will require approximately 2,550 sq ft of ground disturbance and permanent removal of annual grasses.

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