Resolution 894 - Laserfiche WebLink

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• 2. INNOVATIVE SYSTEMS. The City Engineer will review innovative system designs where minimum site conditions are not acceptable for standard system installation. Applications shall be made according to the Variance Section of the Code. a. Lot Size: The lot shall have an adequate area for all existing _and expected improvements in addition to areas of soil suitable for the installation of two on-site sewage treatment systems, known as the "primary drainfield site" to be used initially, and the "alternate drainfield site" to be used should the primary site ever fail. In all cases, the area dedicated for drainfield use shall be identified on the plot plan with sufficient soil and slope data to ensure proper -design. - b. Flooding Hazard: There must be no hazard of flooding in the area'where these systems are installed. C, Shallow Trench Systems: This system is intended for areas of moderately high ground water table depth where percolation rates are in the normal range. 1. Percolation Rate: The percolation rate must be faster than . 60 minutes per -inch and slower than 0.5 minutes per inch. 2. Depth to Groundwater or Seasonally Saturated Horizons: For proper functioning of this system the minimum depth to groundwater or seasonally saturated conditions shall be more than 3 feet. 3. Slope: The land slope in the area proposed for the soil absorption'field shall not be greater than 12%. 4. Position on the Landscape: The system shall be installed on level areas, on top of rises on convex slopes, on sides of rises on plane. The systems shall not be installed in depressions, swales, or drainageways. 5. Soils: The following soil classification series shall ..in most cases be considered unsuitable for the installation of standard systems, but acceptable for a properly designed shallow trench system: Hayden - HbB, HcC2 LeSueur - LtB Nessel - NeB -11