2007-P11206 - septic - Laserfiche WebLink

Home Browse Search

located in landscape positions where there is a large watershed uphill of the location being investigated, free water and saturated soils are observed following heavy precipitation events. In higher landscape positions where little uphill watershed exists the soils do not receive enough inflow to become saturated for long periods of time if at all, water will runoff the surface versus soaking into the sub soil. Soil borings indicate the site is underlain by high chroma loam, and clay loam soils to approximately 5.5 feet. The parent material for the area, high chroma loam soils with many threads of calcium carbonates (often misidentified as low chroma iron reductions), were found to the depth of the borings. Many gray sand coatings on ped faces, calcium carbonates, and reddish iron concretions (referred to as ochres in the geologic culture) were observed. These soil features are a result of the soil parent material not a fluctuating seasonal water table. The confirmation of these features being the result of the soil parent material not a fluctuating seasonal water table was evidenced through the monitoring of three piezometers and one monitoring well from — July 2003 — May 2007. In July 2003 three piezometers were installed at the locations shown on Figure 1 at depths of 66 inches, 38 inches, and 28 inches below the ground surface. These depths were selected based on the results of the soil boring indicating a soil texture, soil color, and/ar soil structure change at ar near these depths. The monitoring well was installed at a depth of 68 inches. The piezometers and monitoring well were installed using the installation instructions obtained from the Army Corps of Engineers. The piezometers and monitoring well were observed monthly from the month of installation through May 2008, excluded November — March. On several occasions the observations were made 1-3 days following a large precipitation event to obtain data during worst case scenarios. All of the observations made yielded the same results, no free water or saturated soils were observed. Soil percolation tests were performed at the locations shown on Figure 1. The results from the tests are in Appendix A. The results of the soil borings, groundwater monitoring, and percolation tests indicate that the site can support a standard subsurface drain field at the proposed area depicted on Figure 1. A soil sizing factor of 2.0 square feet per gallon per day has been selected. Sizing of Treatment S sy tem — The existing residence is a small two bedroom seasonal cabin without a well. To accommodate possible future construction the Onsite Wastewater System (OWS) will be designed to accommodate a three bedroom, Type II single family dwelling with an estimated daily flow from the residence of 300 gallons per day. Description of the Treatment Process— • Primary Treatment - Sewage is gravity discharged from the house to a septic tank. Natural biological activities taking place inside of the septic tank will separate solids and suspended particles. Solids are reduced to some extent through this process. • Final Treatment — Effluent is directed to a new 480 square foot drain field. As the effluent trickles down into the soil biochemical processes remove harmful viruses and bacteria. 2