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D. GROUNDWATER INFORMATION Groundwater elevation measurements were taken on March 23, 1999 from the domestic well that will serve the office. The static water level was measured at 25.98 ft from the top of the casing. A well log for this well was not available. The groundwater under the subject property is being influenced by Interstate 5. West of the highway,the water level is approximately 10 feet below grade. The reason for this influence by the highway is unknown without in-depth studies. As with all groundwater tables, there are fluctuations in elevation. The critical issue with regards to the groundwater elevation under the subject property is that there is sufficient distance between the bottom of the leachline trench or sump and the highest anticipated depth to groundwater for wastewater treatment to occur. Nearby studies have suggested the groundwater directional flow to be toward the west, although this is contrary to what has been observed. The flow cannot be accurately established because of the referenced influence. To determine the extent of past nitrate impact to the underlying drinking water aquifers, a water sample was taken from the well that will serve the future office. This well water contains a nitrate concentration of 29 ppm, which indicates a medium nitrate impact to the respective aquifer(s). Total Kjeldahl Nitrogen (TKN) is the total of the organic and ammonia nitrogen _ fractions and was tested at 5.4 ppm. With a pH of 7.6,the ammonia level may be contributing to this concentration. The water has a relatively high level of Total Dissolved Solids (TDS)at 553 ppm. It is known that the top aquifer in this locale has been heavily impacted from nitrate contamination. Delta N15 tests were completed on the top aquifer and the underlying drinking water aquifers directly south of the subject property. Test results can be found in the Appendix and indicate the source to be predominately from the organic soil fraction and possible influence from sewage disposal systems. From additional studies done in the area, nitrate contamination appears to be widespread in this location. Consequently, mitigation design measures must be implemented for any proposed expansion in the future. E. SURFACE WATER INFORMATION The only body of surface water is the detention basin which is sufficient distance away to not be impacted from septic effluent. III. NITRATE LOADING STUDY RESULTS A. WASTEWATER FLOW CALCULATIONS AND CHARACTERISTICS To adequately determine nitrogen loading from the proposed conventional effluent leachfield, wastewater flows must be determined as accurately as possible. These wastewater flow 3 Naffey Ag Rgsearch