SITE INFORMATION AND CORRESPONDENCE

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Bert E. Van Voris • - 15 - 17 September 2004 Supervising Engineer management,18 yet recommends application of sulfuric acid to improve process water penetration, soil aeration, and crop growth. The RWD strongly recommends that`Bermuda grass be established and permeability maintained with gypsum and sulfuric acid treatment, if necessary."19 It states, "with improved management of salt tolerant crops,the land application system areas will satisfactorily accommodate the period of phasing out process wastewater application as Musco,implements its long- term compliance plan.i20 Comment. The RWD does not cite the technical report describing the soil sampling results obtained in 2003 by Kennedy/Jenks. Soil sampling results presented in Dellavalle's reports, and summarized in the RWD, do not include SAR as required by the MRP. The RWD characterizes site soils as containing very little nitrogen,yet data show instances where soil nitrate concentrations were very high(e.g.,two profiles in Field 95 and profiles in Park West). Most significantly, the RWD does not, but should, utilize in its analysis soil data collected prior to 2000 (e.g., 1999 Annual Monitoring Summary Report dated 31 January 2000). Comparison of recent data with pre-2000 data clearly shows the extent to which Musco's discharge has degraded the quality of site soils. Compared to soil not influenced by the discharge sampled in 1999 in the vicinity of what was then called Field 1 (now called South Ridge), the upper profile of site soils now contain extremely high concentrations of sodium, chloride, and other IDS constituents.21 The impact of salt loading to site soils is summarized below: pH EC Sodium ESP SAR (x 103 ms/cm) (meq/L) Upper profile' 1999 6.5 1.3 1.5 < 0.1 0. 6 2003 9.0 12.73 107.2 39.2 44 .5 Mid-profile2 1999 7. 9 0.4 4.0 4. 6 4.1 2003 8 .2 2.73 20.4 16.2 13. 9 Bottom profile' 1999 7 .4 1.7 12. 8 7. 9 6.7 2003 8.1 1.47 10. 10 10.0 8.9 Upper profile collected at 0" in 1999 and 0-6" in 2003 2 Mid-profile collected at 36" in 1999 and 27-39" in 2003 3 Bottom profile collected at 60" in 1999 and 60-72" in 2003 The RWD should provide data on infiltration rates in the various application fields. Tailwater collection occurs either in constructed channels or, as in the case of Field 95, in natural surface water drainage ways. Discharge Prohibition A.2 prohibits the direct or indirect discharge of wastes within 100 feet of a surface water or surface water drainage course unless such discharge has been authorized by the Executive Officer. Staff will research the case file to determine whether such authorization was provided. In any event, even if it was authorized,the conveyance of tailwater in surface water drainage ways has