Cultus Lake Park Sanitary Sewer Infrastructure Assessment

Fraser Valley Regional DistrictCultus Lake Sanitary Sewer Infrastructure Assessment – Final Report4.7 Discharge to GroundFor all identified treatment options, discharge to the ground is required. The MSRregulation prescribes a certain minimum pipe length for disposal fields based on flow,effluent class, soil percolation rate, type of soil, and the use of effluent filtration andmonitoring. In March 2010, Levelton Consultants Ltd. Conducted a percolation test for theEast Field. Table 15 summarizes the percolation test results for the test holes.Table 15: Levelton Consultant Percolation Test – East FieldPercolationRateTest Hole #Minutes/25mmPH10?01 5.65PH10?02 2.15PH10?03 1.43PH10?04 0.88PH10?05 1.62PH10?06 5.0Average Percolation Rate 2.79Preliminary sizing for the required disposal pipe length for each treatment option werecarried based on an average percolation rate of 2.79 minutes/25 mm. Table 16 providesthe required drainage pipe for each Option.Table 16: Drainage Pipe Lengths for each optionOption 2 Option 3DescriptionClass C Class AMaximum Day Design Flow (m3/day) 1893 1893Percolation rate (minutes/25 mm) 2.79 2.79Number of meters of drainage pipe for each 10 m 3 /d of56.5 56.5maximum daily flowRequired number of meters based on maximum daily flow 10,695 10,695Required number of meters based on maximum daily flow 10,695 6,417and the maximum percentage reductionNumber of Disposal Fields (duty/standby)(2/1) (2/1)Total number of drainage pipes based on 2 duty/1 standby) 16,043 9,626Existing drainage pipes available ?East Field (m) 9,544 9,544Drainage pipes deficit (m)6,499 82Table notes:For effluent Class A, continuous monitoring is required.For Class A, and C, the regulation requires filtration of the effluent prior to discharge to thedisposal field to prevent solids carrying over into the disposal field.For effluent Class A, 40% reduction of disposal field length as per MSR, Schedule 4, Table3 is appliedNumber of meters of drainage pipe is based on the percolation rates in MSR Schedule 4Table 4Project No. 30825 – September, 2012 Page 23