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i Mr. Ben Hall - 2 - 26 May 2004 Musco Family Olive Company feasibility of supplying recycled water to farmland within Westside Irrigation District by means of the District's canal"system. Comment: The thorough characterization of groundwater must include characterization of all constituents that may be potentially impacted by the discharge and of all aquifer zones potentially affected by the discharge, such that a complete evaluation of potential impacts on State waters can be made. The Plan does not indicate whether the subject canals and distribution lines of either District connect to a water of the United States, but, if so, a National Pollutant Discharge Elimination System permit will be required for the discharge. Environmental Issues. Once all wastewater is recycled offsite, the LTU will be seeded or allowed to go --back to natural vegetatioif grid the property encompassing the LTU iriay Eventually be zoriedindus#rial. Y T- In describing environmental impacts of Musco's LTU discharge, the Plan indicates these impacts pose little threat to soil and groundwater duality. The Plan reasons that the low rainfall and the LTU's extensive clay soils will cause inorganic solids to be retained within the first foot or two of the soil profile and it concludes seepage from the 84-million gallon wastewater storage reservoir will be minimal, stating that natural soils underlying the unlined reservoir have a conductivity of less than 10-6 cm/sec. The Plan projects it will tape decades before groundwater affected by Musco's discharge migrates offsite and impacts the valley floor aquifer. In addressing environmental impacts from interim operations, the Plan states that all necessary aeration facilities are installed in the reservoir and that Musco flushes out distribution pipelines following irrigation. The Plan restates that Musco has been working on retaining a neutral third party to monitor for nuisance odor incidents. Comment: Past and ongoing discharge has resulted in storage of salt within the vadose zone, and it has increased the salt content of LTU surface soils to the degree that seed germination has been severely impacted. Sulfuric acid has been used by Musco to dissolve and leach salts from the root zone into the vadose zone to improve germination and crop health. The conductivity and seepage from beneath the reservoir are greater, and groundwater velocity is greater, than represented in the Plan. The dam's blanket drain discharges water may be comprised of over 40 percent impounded wastewater, as estimated in a recent evaluation by Regional Board staff.t Concentrations of decomposition byproducts in MW-16, about 250 feet downstream of the dam, have doubled since the dam began operation. Regardless, slow groundwater velocity is not an acceptable mitigation measure. Closure of the LTU and reservoir, and resolution of impacts on groundwater caused by them, must be addressed in accordance with State Board Resolution 92-49. Aeration apparently still remains insufficient, as self-monitoring data indicates that Musco does not consistently maintain dissolved oxygen levels above the 2 mg/L, the requirement ' Documented in 28 April 2004 Notice of Violation