99--Bioengineering Specifications for Cochiti and Corrales priority sites

Mandatory requirements: No exceptions The bioengineering bankline shall be constructed of blocks of densely packed coconut fiber that fit together to form a continuous, structurally sound bankline protection. The bankline protection will consist of three lines (lifts) of blocks set on top of each other. Each line of blocks will be offset 2 feet towards the bankline from the underlying line of blocks. Each block shall be 16 inches in height and 9 inches thick, with an attached woven coir fabric that extends a minimum of 75 inches from the bottom of the block and a minimum of 48 inches from the top of the block. The fabric shall wrap around the front face of the block. Fabric from each block shall overlap at least 6 inches unto adjacent blocks. The fabric must have a minimum dry strength of 1100 lbs/ft. Stakes used for securing the fabric to the soil shall be a minimum of 2 feet long, with a minimum cross-sectional dimension of 2 inches by 4 inches. Stakes shall be wooden or have similar biodegradable attributes. Blocks and fabric shall be able to provide all of the necessary structural support and erosional resistance until the pole plantings have become established. Coyote willows at a density of 2-3 poles/foot will be planted with each lift of the bioengineered bankline. Each block shall not weigh more than 100 lbs. Each block shall have a unit weight between 7 to 10 lbs per linear foot. The blocks shall be a proven streambank erosion control product. The total linear feet of block needed for the Cochiti priority sites shall be 4,500. The total number of stakes needed for the Cochiti priority sites shall be 5,000. The total linear feet of block needed for the Corrales priority site shall be 1,500. The total number of stakes needed for the Corrales priority site shall be 2,000. Blocks shall be capable of easy installation such that two persons can handle the product. Blocks shall be capable of being anchored by stakes as needed.