Where headroom is restricted, equivalent pipe arches may be used in lieu of circular pipes. (Ord. 644. Passed 8-17-88.)
1043.22 PIPE MATERIAL, CLASS AND GAGE THICKNESS.
All storm sewers shall be either reinforced cement concrete, corrugated aluminum or corrugated galvanized steel pipe. Storm sewers shall be of the proper class and thickness to support the above fill material. Pipe class and gage or thickness shall be noted on the plans. (Ord. 644. Passed 8-17-88.)
1043.23 ALLOWABLE HEADWATER DEPTH.
At all inlets or manholes, the maximum allowable headwater depth shall be one foot below the top of the inlet grate or the manhole cover. (Ord. 644. Passed 8-17-88.)
1043.24 MANHOLES OR INLETS AT HORIZONTAL PIPE DEFLECTIONS.
A manhole or inlet shall be provided at all horizontal deflections in the storm pipe system exceeding five degrees. (Ord. 644. Passed 8-17-88.)
1043.25 MINIMUM AND MAXIMUM COVER.
A minimum of eighteen inches of cover shall be maintained over all storm drain pipes, The top of storm drain pipes shall be at least one-half foot below subgrade elevation. The maximum cover over storm drain pipes shall be ten feet, unless otherwise approved by the Township. (Ord. 644. Passed 8-17-88.)
1043.26 STORM SEWER SYSTEM OUTLETS.
Storm sewer outlet pipes shall extend to proposed stormwater management facilities, natural watercourses and the like. A concrete endwall shall be required on all storm sewer system outlet pipes. (Ord. 644. Passed 8-17-88.)
Stormwater roof drains shall not discharge water directly over a sidewalk, into any sanitary sewer line or into a street or paved area without a straight curbed gutter. (Ord. 644. Passed 8-17-88.)
1991 Replacement
(a) All storm sewer easements through undedicated land shall be a minimum of twenty feet in width.
(b) Where a site is traversed by a watercourse, a drainage easement or right of way conforming substantially with the line of such watercourse and of such width as will be adequate to preserve natural drainage and provide sufficient width for maintenance shall be created, as determined by the Township.
(Ord. 644. Passed 8-17-88.)
All storm sewers and/or drainage swales shall be designed to carry the runoff into a detention basin or similar facility utilized to control the rate of runoff, unless approved otherwise by the Township. (Ord. 644. Passed 8-17-88)
1043.30 RUNOFF CONTROL MEASURES.
(a) Rate and Quantity. The rate and quantity of stormwater runoff from any proposed subdivision and/or land development shall not exceed the rate and quantity of runoff prior to development (i.e. zero increase runoff). This standard shall be maintained for all storms (i.e. both high frequency and low frequency).
(b) Runoff Control Devices. The increased runoff which may result from subdivisions and/or land developments shall be controlled by permanent runoff control measures that will provide the required runoff control specified above. All runoff control devices will be evaluated for their effectiveness to maintain the above-mentioned standard for all storms with a return period of up to 100 years.
(c) Detention Basin Verses Other Available Methods, Detention basins are the most desirable technique for controlling the rate of runoff from a subdivision and/or land development. However, the use of other available runoff control measures is allowable. Runoff control measures other than detention basins may include on-lot berms and on-lot or centralized seepage beds. All pertinent detention basin design standards shall be applicable to any on-lot facilities.
(d) Groundwater Recharge. In general, all runoff control measures shall be designed to encourage groundwater recharge and shall be permitted only if suitable surface conditions are present. Soils testing and certification by a registered professional engineer, geologist, soils scientist, or the like, shall be required before any groundwater recharge system will be allowed.
(Ord. 644. Passed 8-17-88.)