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V. CONCLUSIONS AND RECOMMENDATIONS SSS§ 5.4, 6.8. The shallow subsurface soils at 36" below existing grade where the proposed filter bed is to be installed, reveals a slow permeability. There is a change in soil structure at approximately 5-ft below grade from a sandy clayey silt to a silty sand. Permeability is highly favorable at the 8-ft sump depth. The acceptance/application rate correlated with the observed perc rate as referenced on Page 3 is determined to be 0.123 gals/sq ft/day. Therefore, the shallow filter bed soils at the 30" inch depth will theoretically accept 1,400 sq ft x 0.123 gals/sq ft/day = 172 gpd. If the soil at this depth cannot manage incoming effluent/rainwater, the adjacent sump will temporarily manage inflow. The sump floor exclusively can theoretically manage: 2' x 20' =40 sq ft x 1.2 gals/sq ft/day =48 gpd. In addition to taking advantage of the native filter bed soils for nitrate mitigation, a sustainable factor has also been incorporated into the OWTS design. It has been observed that the roots of deep rooted grasses can penetrate filter fabric to some extent, which separates the backfilled top soil from the drain rock. This penetration allows the grass to utilize an indeterminable portion of the ammonium fraction of the septic effluent as a food source and alleviate nitrate loading. This project specifically utilizes CIMIS evapotranspiration data due to this grass utilization design and the ETo data is correlated with evapotranspiration from reference grass. Data from Region 12 indicates ETo to be approximately 47 inches during the domestic irrigation season of March through October, and specifically for the following months: April: 5.27" irrigation water May: 5.98" June: 7.99" July: 8.46" August: 7.65" September 5.54" Therefore, a landscape contractor should set the irrigation not to exceed this value throughout the irrigation season. In addition, when the lawn is mowed, the clippings must be transported off-site and not allowed to fall back into the grass, otherwise, the nitrogen cycle is completed and potentially adds more nitrogen to the underlying disposal area. NLS§ 4.1. The nitrate loading calculations show the resultant effluent from the subject property will theoretically possess a nitrate-nitrogen concentration of approximately 1.8 ppm which is approximately one-fifth the Federal nitrate Maximum Contaminant Level (MCL). NLS§ 4.2, SSS§ 6.7. All On-site Wastewater Treatment Systems (OWTS) will eventually fail. A reasonably long lifespan for the primary area system can be expected based on the proposed design of the OWTS consisting of equal distribution of effluent under pressure, and the indigenous clay loam soil structure with an acceptable permeability. This lifespan can be measured in years provided the system is not abused with influent consisting of fats, oils, and grease (FOG) and other components that EHD would deem as an illegal disposal, such as petroleum hydrocarbons, etc. 8 Chesney Consulting