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4.4.2 Hydrogeology <br /> The glacial outwash gravels in the river valley and on the <br /> terraces typically have high porosities and permeabilities, and <br /> thus readily transmit ground water. The glacial outwash gravels <br /> generally form unconfined aquifers which may store significant <br /> amounts of water and also recharge water to the underlying <br /> bedrock. Ground water occurs within the glacial outwash between <br /> the soil grains. Ground water also occurs within the bedrock <br /> along secondary fractures, joints, and planes of weakness in the <br /> rock and flows primarily though these zones in the rock. <br /> The movement of ground water through the bedrock aquifers and the <br /> overlying glacial outwash is strongly influenced by topography, <br /> which generally controls the location of recharge and discharge <br /> areas. Ground water within the mountain region generally moves <br /> from topographically high areas (recharge areas) to <br /> topographically low areas within and along stream valleys <br /> (discharge areas) . <br /> The hydrogeology of the Rocky Mountain Geologic Province does not <br /> favor the development of deep ground-water resources; however, <br /> the shallow alluvial ground water contained in the glacial <br /> outwash of the river valley is easily developed. The terrace <br /> river gravels do not contain abundant ground water, probably <br /> because they are too well drained. Ground water in the meadows <br /> northwest of the site represents one of the three sources of <br /> drinking water for the city of Carbondale. Additionally, the <br /> water supply at the site is derived from a shallow alluvial well <br /> on the property. <br /> 4.4.3 Surface Water <br /> The site drainage is primarily to the north. The arrows on <br /> Figure 3 show the pattern of surface water drainage for the <br /> developed portion of the property. The surface water drainage <br /> from the site ultimately discharges into an irrigation ditch <br /> which runs west along the north edge of the property. This ditch <br /> provides irrigation water to the hay meadows in the river valley <br /> and eventually discharges into the Roaring Fork River. <br /> 4.4.4 Public Water Use <br /> The potable water supply for the subject site is provided by a <br /> shallow alluvial well located on the property. Inhabitants of <br /> the river meadows north of the property also depend on the <br /> shallow alluvial aquifer for potable water. The City of <br /> Carbondale public potable water supply comes from three sources; <br /> wells along the Crystal River Valley south of town, surface water <br /> in Nettle Creek, and wells in the Roaring Fork River Valley <br /> 16 <br />