Lehigh Acres, a residential community with a population of about 13,500 and comprising an area of about 94 square miles (243 square kilometres) in the eastern part of Lee County, has been under development since 1954. Prior to development the area was poorly drained. By 1974, more than 150 miles (241 kilometres) of drainageways had been constructed to drain the area. The water-bearing formations underlying Lehigh Acres include the water-table, sandstone, lower Hawthorn, and Suwannee aquifers. The water-table aquifer is usually not more than 30 feet (9 metres) thick; it contains water of relatively good quality, except for iron and color. Water levels in this aquifer probably have been affected by construction of drainage canals. The sandstone aquifer, used extensively throughout the area as a source of water supply usually contains water of good quality although the water is hard and in places may contain concentrations of dissolved solids and iron which exceed the recommended limits of the U.S. Public Health Service and the State of Florida for drinking water. The lower Hawthorn and Suwannee aquifers, usually encountered at depths between 440 and 850 feet (135 and 262 metres), contains water with relatively high concentrations of sodium, sulfate, chloride, and dissolved solids. Three streams, the Orange River, Hickey Creek, and Bedman Creek and the canals connected to them, provide drainage of the area. Except for the Orange River, where the water is of good chemical quality, little is known of the water quality. Similarly, little information is available on stream discharge except for the Orange River where the average annual discharge was 41.1 cubic feet per second (11.6 cubic metres per second) between 1935-46. Most lakes and ponds in Lehigh Acres are hydraulically connected to the water-table aquifer such that factors which affect one also affect the other. Theoretical drawdown curves indicate that the drainage canals may affect ground-water levels to a distance of 6,000 feet (1,800 metres) under certain conditions. Leeland Lake, the only known sinkhole lake in Lee County, is about 208 feet (64 metres) deep and contains water more nearly similar to the sandstone aquifer, although the lake may by hydraulically connected to both the water-table and sandstone aquifers.