wasting, but rather fluvial erosive processes such as sheet flow or channel flow tend to incise and erode to form a singular channel. Therefore, the characteristics of the source area, or potential source area, influence the drainage density and evolution of a drainage basin. Relation to water balance Drainage density is tied to the water balance equation: Where is the change in reservoir storage, R is precipitation, ET is evapotranspiration, Gi and Go are the respective groundwater flux into and out of the basin, Gs is the groundwater discharge into streams, and Qw is groundwater discharge from the basin through wells. Drainage density relates to the storage and runoff terms. Drainage density relates to the efficiency by which water is carried over the landscape. Water is carried through channels much faster than over hillslopes, as saturated overland flow is slower due to being thinned out and obstructed by vegetation or pores in the ground. Consequently, a drainage basin with a relatively higher drainage density will be more efficiently drained than a higher density one. Because of the more extensive drainage system in a higher density basin, precipitation entering the basement will, on average, travel a shorter distance over the slower hillslopes before reaching the faster-flowing channels and exit the basin through the channels in less time. Conversely, precipitation entering a lower drainage density basin will take longer to exit the basin due to travelling over the slower hillslope longer. In his 1963 paper on drainage density and streamflow, Charles Carlston found that baseflow into streams is inversely related to the drainage density of the drainage basin: This equation represents the effect of drainage density on infiltration. As drainage density increases, baseflow discharge into a stream decreases for a given basin because there is less infiltration to contribute to baseflow. More of the water entering the drainage basin during a precipitation immediately following a rainfall event exits quickly through streams and does not become infiltration to contribute to baseflow discharge. Gregory and Walling (1968) found that the average discharge through a drainage basin is proportional to the square of drainage density: This relation illustrates that a higher drainage density environment transports water more efficiently through the basin. In a relatively low drainage density environment, the lower average discharge results predicted by this relation would be the result of the surface runoff spending more time travelling over hillslope and having a larger