Laserfiche WebLink
<br />position, and water holding capacity of the soils; and the time of snow <br />disappearance. Precipitation is almost totally delivered in the fall/ <br />winter/spring period as snow or rain. Most winter/spring snowmelts <br />bring the soil misture to or above field capacity. Excess moisture <br />drains downslope at various rates, dependent upon soil porosity and <br />the hydrologic driving force of the water column upslope (Smith [5]). <br /> <br />Soil parent materials in the area are largely of volcanic or granitic <br />origin with IIlOderate to rapid waterflow rates. Transient grolDld-water <br />tables form on slopes to various depths each winter/spring due to <br />daily snowmelt from 1 to S cm (1/2 to 2 in) of water. Water held <br />between saturation and field capacity drains rapidly through the soil <br />to streams. As a result of rock fracturing and layering, the water <br />frequently appears at outcrop zones as seepage. Below field capacity <br />some lIlOisture movement still occurs downslope. <br /> <br />Water movement rates, water holding capacities, and soil character- <br /> <br /> <br />istics vary according to geologic parent material and other factors. <br /> <br /> <br />Soil properties which are directly related to water movement are <br /> <br /> <br />listed for some of the IIlOre porous soils in this area (table 1). <br /> <br />A nuclear tracing study illustrates typical flow rates. Soil water- <br />flow rates of 2. 7S m (9.1 ft) per 24 hours were measured when a <br />tracer was injected at 2800 mm (109.8 in) depth and did not mix with <br /> <br />13 <br />