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Ben Hall -2- 12 May 2011 Horacio Ferriz Musco Family Olive Company concern. The well development sheets indicate all three newly installed wells were noted as producing a lot of very fine sand and purge water remained very turbid at over 1000 NTUs. Volumes purged from these newly installed wells ranged between 12.1 gallons and 19.1 gallons, yet the NTU value never dropped below 1000 NTUs. The US Environmental Protection Agency's Test Methods for Evaluating Solid Waste, Physical/Chemical Methods, SW-846, Chapter 11, 11.4.3 (c) states: "samples containing less than 5 N.T.U. turbidity are acceptable for analysis when the analytic method is sensitive to turbidity (such as the analysis of metals). Samples containing greater than 5 N.T.U. are only acceptable when well development is certified by a qualified hydrogeologist as the best obtainable." According to ASTM Standard D5092-04: Standard Practice for Design and Installation of Ground Water Monitoring Wells: "...development should be continued until representative water, free of the drilling fluids, cuttings, or other materials introduced or produced during well construction, is obtained. Representative water is assumed to have been obtained when turbidity readings stabilize and the water is visually clear of suspended solids... The timing and duration of well development and the turbidity measurements should be recorded on the well completion diagram." As discussed during our conference call on 11 May 2011, Musco must re-develop the wells to obtain the lowest turbidity value consistent with the SW-846 and the ASTM Standard discussed above. If the wells can not be cleaned up due to improperly sized well screens and filter pack, then these wells may need to be replaced. As required by the ASTM Standard, the timing and duration of well development, and turbidity measurements, shall be recorded on revised well completion logs. Determination of Groundwater Flow Direction The report discusses the use of"equilibrated" groundwater elevations from wells MW-10R, MW-18R, MW-20R, and MW-21 R to construct a groundwater flow model across the area of the ponds and states that the gradient across this area is 0.01 feet per foot with a groundwater flow direction toward the northeast. To calculate groundwater flow direction and gradient all the wells of interest in the vicinity of the surface impoundments must be used. Those wells include: MW-10R, MW-12, MW-17, MW-18, MW-18R, MW-20, MW-20R, MW-21, MW-21R, MW-22, and MW-32. This list does not incorporate all wells surrounding the surface impoundments, but only those that are newly or recently installed or have recently gone dry. Groundwater elevations for the newly installed wells are not reported on Figure 7 or Figure 8; the report does not provide field data sheets or a table summarizing depth to water measurements of the newly installed wells recorded during sampling events; and the report does not provide calculated groundwater elevations above mean sea level. The report California Environmental Protection Agency