Section Env-Wq 713.13 - Aerated Lagoon Design: Embankments, Dikes & Bottom(a) Aerated lagoon dikes, embankments, and bottoms shall form a stable structure impervious to seepage of lagoon liquid.(b) The minimum top width of a dike or embankment shall be 8 feet to permit access by maintenance vehicles.(c) Aerated lagoon dikes and embankments shall have inner faces not steeper than a 3:1 slope nor shallower than a 4:1 slope, and outer faces not steeper than a 3:1 slope.(d) Aerated lagoons shall be designed such that surface water shall not flow or drain into the lagoons.(e) Aerated lagoon dikes shall be designed to provide a minimum of 3 feet of freeboard above normal lagoon water surface elevation.(f) For aerated lagoon systems, the design water depth shall range from a minimum of 10 feet to a maximum of 20 feet.(g) Seeding and erosion control shall be as follows: (1) Outside slopes shall be seeded with perennial type, slow growing, spreading grasses that minimize erosion and can be mowed; and(2) Inside slopes shall have rip rap or comparable material of suitable size and weight installed from the top of the dike to at least one foot below normal lagoon operating level to protect the slopes from erosion and wave action.(h) The lagoon bottom shall be smooth and level at all points. Finished elevations shall vary not more than 3 inches from the average elevation of the bottom.(i) A minimum separation of 4 feet between the bottom of the pond and the maximum ground water elevation shall be provided unless an effective underdrain system is provided.(j) A minimum separation of 2 feet between the liner bottom at the bottom of the lagoon and any bedrock formation shall be provided.N.H. Admin. Code § Env-Wq 713.13
Adopted byVolume XXXIV Number 46, Filed November 13, 2014, Proposed by #10693, Effective 10/15/2014, Expires10/15/2024.