STREAM ASSESSMENT IN THE LITTLE CONESTOGA CREEK WATERSHED

Following rapid deforestation in the 1700's as a result of European colonization, Lancaster County, Pennsylvania is again experiencing rapid land-use change as highly productive agricultural lands are converted into suburban development. Since the 1950's the County's population has increased by to 15% per decade and is presently around 460,000. Between 1970 and 1990 the proportion of county land defined as urban more than doubled. These changes coupled with a greater awareness of the links between land use and water quality have resulted in numerous attempts to improve local streams through stream restoration projects.

The goal of this study is to comprehensively assess one of the major watersheds in Lancaster County (the Little Conestoga Creek) to determine its potential for stream restoration. Land use changes can influence both the physical dynamics of a stream as well as the water quality. Water samples taken from the Creek have shown elevated level of nutrients in several areas with a correlation to land use, agreeing closely with a similar study conducted by the USGS (Loper and Davis, 1998). Remote sensing and aerial photography since the 1940's integrated into a Geographic Information System (GIS) has enabled the changes in land use and stream morphologies to be analyzed over time. Other field data such as sediment cores and stream cross sections have been integrated into the study to comprehensively quantify temporal variations in the stream. This data, integrated with the water quality and aerial photography, has allowed the progression and evolution of the stream to be linked to the change in land use over time. This historical approach to studying the watershed has proved successful in determining how the stream morphology has changed and is currently changing. This is propitious for future restoration projects because it shows which sites are most heavily impacted, how they are responding to change, and thus what steps will be most productive and advantageous on a long-term basis.