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Cr2. Proposal to monitor and verify the engineered system is working(i.e., sampling): have conducted well-over 500 nitrogen environmental impact tests, studies and assessments over the past 30 years in both the agronomic and civil engineering disciplines. For my projects where I want to determine nitrate concentrations within the vadose zone water, I use a Soil Solution Access Tube (SSAT)made by the Irrometer Company. I am proposing to use this device for sampling effluent under the filter bed after it travels through the soil environment for 2 ft from the soil-effluent interface. The exact location of the filter bed perimeter must be denoted by the installer. An auger is used to drill a boring at an angle under the filter bed. A 48" SSAT is then used to extract a vadose zone water sample as illustrated in the attached data sheets. 3. A clarification is requested on using a rainfall recharge rate of 11 inches/yr. First of all,there are many different methods to assess or quantify nitrate-nitrogen loading from a source or sources,just not the Hantzsche/Finnemore Equation. I've used the Hantzsche/Finnemore Equation most of the time for EHD Nitrate Loading Studies because I believe that from a mathematical standpoint, it determines quantities and concentrations very well, provided the data used in the equation is as accurate as possible. Within this equation, I have always used rainfall amounts derived from the attached San Joaquin County Department of Public Works Isohyetal Map of Mean Annual Precipitation, which is relatively accurate. When the authors submitted their paper on nitrate loading (Hantzsche,N.N. and Finnemore, E.J. 1992. Predicting Ground-Water Nitrate-Nitrogenpacts. Ground Water. Vol 30,No.4:490- 499) in 1992, evapotranspiration was poorly understood. It wasn't until 2001 when the American Society of Civil Engineers completed extensive studies and calculations on evapotranspiration that it became the scientific method that it is today for evapotranspiration studies and information. In my opinion, it is correct for Hantzsche/Finnemore to have the annual volume of rainfall for any given location in their equation because this rainfall volume has the potential to drive nitrate down to the groundwater. The only reason I include the Evapotranspiration Table in my studies, and have done so for the past 18 years, is to demonstrate that 1.) Deep percolation will only occur in the winter months when nitrification is at its lowest due to lower soil temperatures, and 2.)Evapotranspiration is a quantifiable phenomenon that proves that by keeping a leachline or filter bed as high in elevation as possible (or close to the soil surface), significant transpiration(if there is plant life over the disposal field) or bare soil evaporation will readily occur during the referenced months out of any given year. 4. The"very large nitrate loading safety factor" is derived by using 2 people per bedroom of any given single family residential structure in conjunction with the assumption that each of those people will use 69 gals per capita/day, 365 days per year. This is not reality and severely inflates the nitrate loading. Demographic data should be used in these calculations. Page 2 of 3 Chesney Consulting