Map of land use and location of sites sampled in the WCC watershed.
White Clay Creek
The watershed is a combination of forests (22%), agriculture (51%), and development (13%). Land use is variable in the watershed but mainly rural (agriculture) in PA and mostly suburbanized (homes and industry) in DE.
Analyses indicated Good water quality in the headwaters but as the watershed becomes larger water conditions became more degraded corresponding to an increase in impervious surfaces (e.g., parking lots and roads), and developed areas (e.g., buildings).
Poor water quality conditions in the Lower Mainstem of WCC should not be attributed solely to changes in land use since water quality is Poor below the East, West and Middle Branches, including sites in the forested State Parks, before it ever reaches the heavily populated and developed area of Newark, DE.
WCC & Schuylkill Watersheds
An analysis of WCC sites and sites in the Schuylkill watershed showed that more forests and less agriculture in the watershed resulted in higher water quality.
In the Schuylkill watershed there is a clear relationship between forest, agriculture, and water quality, but this pattern is less clear for the WCC watershed.
Contrary to expectation some of the best water quality sites in WCC have the highest percentage of agriculture and lowest forest.
The relationship between population density and MAIS also differs between watersheds: water quality is much more degraded in the WCC watershed compared to the Schuylkill for a given population density.
Land use and MAIS scores for Stream Watch sites (1-12 yrs of data) in WCC and 138 sites in the Schuylkill (Sch) watershed (1-14 yrs of data). R2 show the strength of the relationship between the MAIS scores and land use variable for Schuylkill and WCC sites (i.e., the closer to 1.0 the stronger the relationship). See report for details.