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CONFIDENTIAL ATTORNEY-CLIENT PRIVILEGE Mr. Scott'lalm Cassel Dlahm Fag uncles, LLP September 9, 2008 Page 3 L Chesney's design application rate was far too high for the actual BOD concentration. For high strength wasted atcr, Crites and Tchobanoglous (1998, 'fable 13-7) recommend loading rates about 20"a of those used by Chesney in the prinnary area. Chesney in fact does reference Crites and Tchobanoglous (1998), but did not follow the recommendations in the reference. 2. Even for the assumed domestic strength wastewater, his stated design application rate (I gpd/ft') for the primary disposal system was much higher than the application rates recommended by Crites and Tchobanoglous or State Water Resources Draft AB 885 Regulations or EPA for the 42 min/in percolation rate he measured in the double ring infiltration test performed in the primary area. 3. Chesney claims that his design is for a filter bed,yet he uses individual infiltrative chambers with segregated infiltrative surfaces rather than a continuous true gravel-lined filter bed. Chesney uses the gross outline of the primary area (1,800 ft) in his calculation of infiltrative area versus the actual open area contained under the Infiltrator chambers (1,030 ft'). Including the louvered side areas in the infiltrators, the total area would still be only 1,440 ft'. He thus overestimates the design infiltrative surface area by 25 to 75%. 4. Chesney identifies the soil at the bottom of the infiltrators as ML or MI./CL. This would be considered "silt and/or sandy clay loam" under the San Joaquin County regulations, corresponding to a 0.225 soil factor. The total conventional leach line requirement should therefore have been 540 lineal feet. Chesney has only supplied 412 lineal feet in the primary disposal system. The secondary disposal system does provide an additional 80 lineal feet of leach line and 140 equivalent feet of leach line in the seepage pits, although the primary and secondary,systems cannot be operated concurrently. While the above four issues undoubtedly contribute to reduced primary disposal system capacity, the main reason for the very poor performance of the primary disposal system to date is that the system was constructed in wet,puddling conditions. This very likely resulted in the formation of a surface seal and in compaction of the soil under the Infiltrators. Four-hour duration percolation tests performed by Brown and Caldwell on two of the Infiltrator laterals gave an average final percolation rate of 0.44 inches per hour (136 minutes/inch), which is 18% to 28% of the values from the original tests by Chesney, confirming that in-sim percolation rates are unusually low. Construction in excessively wet conditions also resulted in compression of the Infiltrators into the underhving mud during cover placement, thereby furtherreducing infiltrative surface area and effluent storage volume. This was confirmed by excavation and inspection of the far southwest lateral by the contractor when requested by Mr. Schenone. Chesney did specify scarification of the soil/effluent interface on the Preliminary Septic System Schematic. However,Chesney did not provide any guidance regarding prevention of compaction, compression and surface sealing for construction during wet periods. Chesney also did not inspect the construction as he had reported]), promised to Mr. Schenone.