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Hennepin Conservation District <br />Repairing Erosion Damage <br />1.0 Slope Restoration <br />Eroded areas can be restored by regrading existing material. Clean dirt fill should <br />be used where additional material is needed. The regraded surface must have a <br />uniform slope with a level cross-section; it must not have any depressions or bumps. <br />The fill should be covered with four inches of loamy topsoil for the vegetative cover. <br />Where possible, eroded areas should be regraded to slopes no greater than 1 on <br />2 (50% grade;. This can be achieved by extending the regraded slope at the toe, <br />r,,*ting the slope back at the crest, or constructing a retaining wall at the top of the <br />slued. <br />Six-inch diameter drains must be installed along the toe of all affected slopes and <br />behind all retaining walls. Corrugated polyethylene erforated tubing is <br />recommended. Drains shall be laid to a neat fine and grade in a trench excavated <br />into undisturbed soil. Thera should be no void spaces between the tubing and the <br />walls of the trench after backfilling. Turn both ends to provide outlets. Except for <br />outlets, drains must be three feet below the final graded surface. A dent guard <br />must be placed over all out'ets. <br />Retaining walls can be used to shorten the regraded slope. The retaining wall <br />should be placed at the top of the s!cpe and not exceed five feet in height. Six-inch <br />drains must be installed behind all retaining wails using specifications cited above. <br />Drains should be Placed at the same elevation as the bottom cf the exposed wail ar,ri <br />four feet behind *he wall where possible. An engineer must be consLlted for the <br />design of retaining walls needed to protect structures. <br />205 Ridge Plata Bldg 12450 Wayrata Poulev,ard Minnetonka, Minnesota 55343 Telephone (t)12) 5.4-85T2 <br />