SECTION 245 - SILT DIKE
245.01 Description. This work consists of furnis hing, installing, maintaining and
removing temporary silt dikes. Silt dikes shall be used for velocity reduction of stormwater run-off. Silt dikes shall be considered to have “minimal” capabilities for sediment filtration of stormw ater run-off. With the ex ception of placement along the ends and edges of a construction bridge across a Water of the U.S., silt dikes shall not be used as a discharge structure or the last sediment control item in a “BMP train” prior to stormwater discharge off Department Right-of-Way or into Waters of the U.S.
245.02 Materials. Silt dikes shall have a dike height of at least nine inches (9”) in the
center. The outer cover shall be a woven ge otextile fabric placed around the inner plane and allowed to extend beyond at least one side of the device for a minimum of two feet (2’) to form an apron. The device may also have aprons on both sides, each of which shall extend from the device a minimum of two feet (2’). In the event that the silt dike has an apron extending from only one side, geotextile fabric shall be placed under the silt dike as shown on the standard drawing. Silt dikes shall rebound to their originally installed height when driven over by vehicles or equipment. Silt dikes shall not be damaged when driven over by vehicles or equipment. The silt dike shall also be one listed on the Department’s APL.
245.03 Construction Requirements. The flexibility of the materials in silt dikes allows
them to conform to various channel configurations. The dikes shall be attached to the ground with wire staples. The staples shall be No. 11 gauge wire and be at least six inches long. As a minimum, the staples shall be placed as recommended by the manufacture. Prior to placement of the silt dikes, the Cont ractor shall make sure the surface on which the dike is to be placed is flat. The silt di kes shall be placed in ditch, keeping excess fabric extended up and downstream of the dam. Excess material shall be trenched into the ground on the upstream end and stapled on the downstream end. A minimum 6-inch overlap between end sections shall be required should the width require multiple silt dikes to be installed. The overlapped end se ctions shall be connected with wire wraps or staples every 12 inches on center. The dike aprons shall be entren ched at the upstream side and anchored to the ground at downstream end using staples. This device can be used on surfaces that do not allow for trenching by securing the aprons with sand or gravel bags or other manner as described by the manufacturer. The device can be easily removed for maintenance and is considered to be reusable. Silt dikes which do not
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