The drainage basin or watershed is a zone of production, where precipitation accumulates to be delivered to streams and rivers, and sediment is produced by landscape erosion (Schumm, 1977). When precipitation falls on a landscape, some portion of the water seeps into the ground and makes its way to the drainage network as shallow subsurface throughflow or as slow flowing groundwater. Water that does not infiltrate into the subsurface flows across the surface and moves rapidly to the drainage network as direct runoff. Because flow rates vary with pathways, the hydrology of the stream network is directly related to the relative percentage of water following various flow paths from the landscape to the drainage channels. Flow path depends on a number of drainage basin and climatic characteristics such as the infiltration capacity of the soil and bedrock, topography, vegetation, seasonal effects (frozen ground, snow cover, and foliage), variation in precipitation intensity through time, and land use (Burt, 1992). Each drainage basin will have an annual hydrologic regime that results from the integration of all of these variables.