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CA t1ro-& J A N 0 81983 �o io o. g ROUTE 2 • BOX 605 • WOODLAND, CALIFORNIA 95695 • PHONE (916) 662.6516 January 5, 1983 Mr. Bob Fujii, Area Engineer California Regional Water Quality Control Board Central Valley Region 3201 S Street Sacramento, CA 95816 Dear Bob, Enclosed hemewith are the results of analyses of soils beneath the evaporation ponds at Forward, Inc. They are highly significant, and strongly suggest- that the ponds leaked a substantial amount of brine into the groundwater; perhaps as much as 2570 of all the brine that has been received since the outset of this operation. I will explain the reasoning that leads to this conclusion, but first, it may be instructive to explain the type of analyses and what they mean in general terms. These analyses were made on saturation extracts. This is a standard soils procedure that is well known to soil scientists. It is known further that for a wide range of soils, the amount of water necessary to saturate a soil is roughly double the amount of water that the soil will hold at field capacity, so it follows that if one wishes to estimate the concentra- tion of the salts in the soil at field capacity, he must multiply the sat- uration extract analyses by two. The most significant constituent in the analyses may be the chloride. You will note that the chlorides are high; in the order of 1000 to 140 mg/1. This in itself is very good evidence that the ponds have leaked a signicant amount of brine. into the soils beneath them. I will explain why this is so. According to all persons with whom I have talked, including Forward, Inc. personnel, neighbors, etc. this soil was farmed to irrigated crops before it was turned into a dump. Furthermore, the source of irrigation water was deep wells on or near the property* I have perused the analyses of wells in the immediate vicinity and determined that the irrigation water is very low in chlorides--considerably lower than bicarbonates. The enclosed analyses show that the soil solution contains roughly 10 times as much chloride as it does bicarbonate. Further, chlorides make up less than 10% of the total dissolved solids in the groundwater, as opposed to about 50% of the total dissolved solids in the soil solution from beneath the ponds. In short, the soil solution from beneath the ponds does not at all resemble the groundwater that was used to irrigate the site. *It is well known that agricultural soils tend to come into chemical equi- librium with the water with which they are irrigated--to the extent that soil' scientists can predict what a soil will be like after having been irrigated for -a time with7a' cert quality water