Loading...
HomeMy WebLinkAboutNCG020923_Bayview Sand Mine - Water Height Control-2_20171213Water Height Control: Construction Details Half-pipe Water Level Control with Flash Board Risers NRCS Code 587 Bayview Sand Mine Powells Point, NC Currituck County DESCRIPTION A structure in a water management system that conveys water, controls the direction or rate of flow, maintains a desired water surface elevation or measures water. Water height control structure is standard structure used by agricultural and horticultural farms in North Carolina to raise or lower water height in ditches and ponds per need (NRCS). Water height control structure to be installed in the north berm of the sedimentation pond at the Bayview Sand Mine. Overflow to be directed down stabilized ditch to nearby Betsy’s Creek, eventual outflow to Currituck Sound. PURPOSE To convey water from one elevation to a lower elevation within, to, or from a water conveyance system, such as a ditch, channel, canal, or pipeline designed to operate under open channel conditions. Typical structures: drops, chutes, turnouts, surface water inlets, head gates, pump boxes, and stilling basins (NRCS). This water management system will be used to maintain a maximum water surface elevation in the sedimentation pond at the Bayview Sand Mine. Sedimentation pond is a part of the dewatering management system of the Bayview Sand Mine, used to remove settleable matter and turbidity from mine dewatering wastewater. CONSTRUCTION Structure consists of 26’ x 3’ horizontal galvanized steel culvert running under the sedimentation pond berm . A vertical 6’ half pipe 52” x 30” is attached on the north end of the culvert with stacked flash boards allowing adjustable height of the water level in the sedimentation pond. Water flows over the flash boards and into the discharge pipe and down the rip-rap stabilized ditch. Overflow ditch is lined with riprap for 20 feet down its length. Existing slopes adjacent to the culvert are heavily grassed with natural grass and weeds with no erosion present. MAINTENANCE Structures will be checked and necessary maintenance, including removal of debris, shall be performed after major storms and at least semi-annually. Ken Elliott, consulting December 3