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with refuse as the landfill operation proceeds. When considered by itself, the lost of approximately 290 to 300 acres of topsoil may not be significant on a county or state-wide basis. However, it would contribute to the cumulative loss of potentially arable land in California. To illustrate this trend, of the 100.2 million acres of land in California, 39.0 million acres of land were in agricultural use in 1960. This has been reduced to 33.5 million acres by 1980, an average of 275,000 acres less per year. Obviously, this cannot continue indefinately without seriously reducing our food producing capability. Another matter for consideration relative to soil impacts is erosion. Left in its natural state, soils on-site are not particularly prone to erosion because they are stabilized by the root systems and above ground portions of established vegetation. However, if this vegetation is removed and the compacted earth is loosened by earthwork, erosion and subsequent siltation of receiving waters could become a significant problem. The rate of erosion for denuded and disturbed soils can be many times that of natural, stabilized soils. In the soils section it has been identified that erosion is the dominant limitation of soils on-site. Erosion is caused by rainfall and runoff as the kinetic energy of falling rain drops displaces soil particles. Rain falling on denuded areas runs off, carrying suspended soil particles downslope and into minor stream channels. As the volume and velocity of runoff increases, deposited particles are scoured from the channels and transported farther downstream. Deposition �,,iill occur again when the runoff slows down such as when channel slope decreases or when barriers or dams are encountered. However, there are many erosion control methods which could be employed to mitigate this impact. The mitigation section discusses possible measures. Virtually all soil impacts discussed in this section would be character- istic of most sites for a landfill, perhaps worse in other locations. Loss of potential arable land, increased erosion and loss of topsoil are inherent impacts of this method of solid waste disposal. Hydrologic Conditions/Water Quality Surface Water Surface water runoff patterns would be slightly modified from its present condition. Sheet runoff which flows to the north and northwest would instead be diverted by temporary and permanent diversion structures to a branch of South Paddy Creek. An increase in runoff contributed to the creek by this modification should be anticipated. Only during periods of unusually heavy participation would there be any noticeable impact on the quality of the surface runoff. During periods of heavy precipitation, both the excavated and filled areas would be subject