Relationship between annual runoff and watershed area for the eastern United States

Runoff contour maps were used to estimate annual runoff for about 1000 ungauged sites in the eastern U.S.A. as part of a study of the long-term effects of acidic deposition on surface water chemistry. To resolve concerns that the use of contour maps might introduce a bias because of the size of the ungauged sites in relation to the sizes of the catchments used in developing maps, the relationship between annual runoff and catchment area was determined for two regions. Runoff was not directly correlated with catchment area, nor was runoff normalized by precipitation so correlated.