WATER RESOURCES OF ORANGE COUNTY 81
diverted to the artesian aquifer through drainage wells. However, during extremely wet years, such as 1960, flow into these wells when added to the normal recharge raises the piezometric surface so that the wells in some lakes refuse to take water and some wells even discharge water into the lakes.
Surface outflow from a lake may be conveyed in open channels and culverts or pumped out through pipes. Conceivably, open channels can be used to drain any of Orange County's lakes. However, gravity drainage of many of the landlocked lakes would be expensive because of the depth and length of channel excavation required. For instance, to drain Lake Sherwood through an open channel would require a channel more than 10 miles long with cuts up to 45 feet deep. The channel would, of course, provide drainage for those intervening lakes through which it could be routed, but it might drain some of them dry.
Open channels require considerable maintenance; they require wide rights-of-way; they are often unsightly; and they break up the continuity of the land; they interfere with land transportation; and they may add to water-control problems elsewhere by introducing water where there is already an excess. A combination of open channels, culverts, and pumps can often be used to advantage.
Artesian wells can be used to remove water from or to put water into a lake. If the lake level is higher than the piezometric surface, water from the lake will flow into the well; if the piezometric surface is higher than the lake level, water will flow out of the well. The natural direction of flow can, of course, be reversed by using pumps; however, pumping of water down drainage wells is prohibited by State Board of Health regulations.
PROBLEMS
Surface-water problems in Orange County stem from two main causes---floods and water deficiency.
Types of flooding that occur in Orange County are: (1) floods resulting from surface runoff which are short-lived, and (2) floods resulting from high ground-water conditions which persist much longer. Type 1 floods are far more frequent than type 2 floods. Type 1 floods are confined to areas contiguous to streams and lake depressions that have large surface inflows. Type 2 floods are confined mostly to lake flood plains, "Bottoms" in closed basins and reach a peak at about 6-year intervals. Because of the long duration