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LOGE 1928: American Crane Rental Page 2 May 29, 2019 Discussion of 2012 Provost & Pritchard Report The Provost & Pritchard report assumes that a lot line adjustment will reduce the size of the parcel, and hence the project area (A), to 8.42 acres. This is different from the current project, which will include 11.80 acres. For employee use numbers, Provost & Pritchard state that "it is known from Mr. Powell that there will be a maximum of 31 employees, which include office personnel, truck drivers and mechanics. Approximately twenty one of these employees will be truck drivers. Customers are anticipated to be minimal at two per day for a total of 33 people on-site daily." The facility is assumed to operate 255 days per year, equivalent to a five- day work week. In fact, the corresponding Use Permit indicated 35 employees and three customers, for a total of 38 people on-site. These numbers are similar, but not identical, to the current employee levels to be discussed later in this letter. Provost & Pritchard use the value of 15 gallons per person per day to determine the daily effluent flow. This value was derived from the San Joaquin County Sewage Standards, and was intended for septic system sizing; septic sizing numbers are not appropriate for nitrate loading determinations because they contain a surge factor. Provost & Pritchard further state that "the EHD allows a reduction of the 15 gals/person/day for transient workers such as truck drivers down to 5 gals/person/day. But as a safety factor, the 15 gals/person/day will remain to demonstrate that even with this incorporated safety factor, the nitrate loading calculations ... comply with EHD requirements." In fact, Provost & Pritchard apply the 15 gal/person/day use rate to the customers as well, though it is highly unlikely that customers at a crane rental facility will stay on the site long enough to use the restroom multiple times. The resulting use rate for employees and customers was calculated by Provost & Pritchard as follows: (31 employees + 2 customers)(255 days)(15 gal/person/day) = 12,225 gal/year = 345.8 gal per day (gpd) Through a discussion of various use values and nitrate reduction within the septic tank, Provost & Pritchard arrive at a value of 82 mg/L-N as the nitrate concentration of the septic effluent (Nw) at the American Crane facility. This value is similar to the 85 mg/L- N value typically used by Live Oak for commercial projects. Provost & Pritchard assume that rain has a concentration of 0.1 mg/L-N (Nb), though Hantzsche and Finnemore use the value of 1 mg/L-N. Provost & Pritchard assume that the soil on the Site will denitrify (d) at a rate of 15 percent based on the "fine-grained silty sand soil" located on the Site. Live Oak would assign a fine-grained silty sand a typical 25 percent denitrification factor (Hantzsche and Finnemore) due to its silt content.