Laserfiche WebLink
June 16, 2022 <br />102 <br /> <br />Specifications for Construction of Public Utilities, as it presently exists or may hereafter be <br />amended. <br />2. Manholes shall be installed at the end of each sewer, at all changes in sewer size, grade, <br />pipe material or alignment and at all junctions. The maximum permitted manhole spacing <br />shall be based on Table 19. Manhole Spacing. <br /> 3. Curves in pipes or box culverts without an inlet or manhole are prohibited. Tee joints, <br />elbows and wyes are also prohibited. <br />4. If a proposed lot or development site is to be graded so as to redirect post development <br />flow into a gutter or when an existing gutter or ditch is to be integrated into the proposed <br />stormwater conveyance system, a maximum depth of six (6) inches shall be permitted in the <br />roadside gutter or ditch. <br />(k) Retention and Detention Basins. <br />1. Retention basins and detention basins shall be designed to safely discharge the peak <br />discharge of a post development one hundred (100) year frequency storm event through an <br />emergency spillway in a manner which will not damage the integrity of the basin. <br />2. Retention basins and detention basins and water carrying facilities shall be stabilized in <br />accordance with current engineering and Soil Conservation Service practices. <br />3. Retention basins and detention basins shall be designed and maintained to insure the <br />design capacity after sedimentation has occurred. <br />4. Along rivers and other areas prone to bank instability, retention and detention ponds shall <br />be located in areas that will decrease the probability of bank failures or accelerate existing <br />bank failure problems resulting from the saturation of river bank soils.All discharge pipes <br />shall terminate with a precast concrete or corrugated metal end section. <br />5. Basins which are not designed to release all stormwater shall be specifically identified as <br />retention basins or permanent pond basins and shall provide aerators and/or fountains to <br />prevent stagnant water. All other basins shall have provisions for de-watering, particularly <br />the bottom and shall not create swampy and/or unmaintainable conditions. Low flow <br />channels and tile fields may be used to de-water the bottom of the basin. Discharge <br />structures shall be designed to eliminate the possibility of blockage during operation. <br />6. Retention basins and detention basins which are designed with earth fill dams shall <br />incorporate the following minimum standards: <br />a. The maximum water depth shall not exceed ten (10) feet, unless a variance is <br />approved by the Planning Commission. <br />b. The minimum top width of all dams shall be five (5) feet. <br />c. Basins without restricted access shall have impoundment areas with side slopes no <br />greater than six (6) horizontal to one (1) vertical. Basins with steeper side slopes <br />shall be protected by fencing that will discourage access. Fence material shall