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r2 IV. SEPTIC SYSTEM OPERATIONAL PARAMETERS AND COMPONENTS The primary and 100%replacement areas, in addition to distances in relation to existing and future domestic well locations,must be denoted on the Site Plan and/or septic system installation permit for submittal to EHD and other possible County Departments. Future septic system operation for Parcels 2 and 4 is as follows: Effluent filters are to be installed at the septic tank outlets. Effluent will gravity flow from each septic tank, travel to a four-hole D-box and be equally distributed between perforated leachline pipes within a conventional leachfield. A 42 inch diameter seepage pit shall be installed at the end of each leachline. One hundred percent replacement areas should be easily accommodated on each Parcel due to the area of each Parcel. IV. CONCLUSIONS AND RECOMMENDATIONS NLS§ 4.1. The nitrate loading calcul ions show the resultant effluent from the project, assessed as a whole, was determined to b 6.2 pp e trogen, which is below the Federal nitrate Maximum Contaminant Level f 10 ppm itrate as nitrogen, or 45 ppm as nitrate. Each proposed Parcel taken individually finds that two of the four Parcels slightly exceed the MCL and are certainly within a margin of error. NLS§ 4.2, SSS§ 6.7. It is the policy of the EHD to monitor water wells on a Parcel where the nitrate loading calculations indicate exceedance of the MCL. It is my professional opinion that monitoring is not necessary for this project because exorbitant wastewater flows have been incorporated into the c culations as a safety factor. Secondly,the indigenous soil analytical test results demonstrate very low concentrations of subsurface soil nitrate-nitrogen caused by significant suppression of nitrification and promotion of denitrification, thus leading to low nitrate concentrations in the groundwater. Even with extensive agricultural production upgradient to the property, low nitrate concentrations are observed ink e'underlying groundwater. SSS§ 5.4, 6.8. The surface and subsurface soils obviously possess a degree of permeability because stormwater infiltrates and percolates, which was observed after a series of heavy rainfall events. Given the soils underlying the subject property show inadequate permeability, it is my professional engineering recommendation to enlarge the system to the next upgrade (i.e., a 3 bedroom house to be upgraded to a 4 bedroom system). For example, if a 3 bedroom house is to be constructed which would call for a 1200 gallon tank and a leachfield infiltration area of 1098 sf, instead install a 1600 gallon tank and an infiltration area of 1467 sf. If a four bedroom or larger home is proposed to be constructed, a 2000 gallon tank and 1812 sf shall be installed. If the lowest wastewater application rate of 0.100 gals/sf/day is applied to the infiltrative area of 1467 sf,we find that a leachfield area will manage 147 gpd. A wastewater flow of 147 gpd is a reasonably expected volume from a 3 bedroom/2 bath house. Page -10- Chesney Consulting