University of Kentucky
Geomorphic Changes in Inner-Bluegrass Streams, Lexington, KY
Institution
University of Kentucky
Faculty Advisor/ Mentor
Christopher Sass
Abstract
Stream effects resulting from urbanization can be difficult to assess, especially without quantifiable measures. Agencies have spent billions of dollars rehabilitating streams to decrease these effects through Best Management Practice usage. This study’s goal was to establish monitored sites of urban effected streams, measuring their morphology and hydrology long term within Kentucky’s Inner-Bluegrass Region. Four initial stream reaches representing different riparian variables and flow regime in the same watershed were chosen and established over the summer of 2014. Reach selection was based on riparian vegetation and stream flow. Establishment of reaches included longitudinal profiles, pool and riffle cross-sections, and pebble counts. Rosgen classification was used to establish baseline conditions. As a part of the historical monitoring, documentation of urbanization, how urbanization influences streams’ geomorphic characteristics, and how those characteristics have changed. Once establishment was complete, a process of analyzing data, researching past stream movement through the landscape and classification, and comparing past and present geomorphic characteristics began. We assessed lateral stream movement using historical aerial photographs, along with measured erosion and changes to the stream channels. Stream reaches were more entrenched, straighter, and wider than historically, encouraging higher flow velocities and increasing the rate stream channels carve the landscape through erosional processes. As our research continues, we expect results to illustrate streams in the urban Inner-Bluegrass region function much differently than in the past. This knowledge will aid us in creating systems that work for the new hydrologic regime being delivered to urban stream sites.
Geomorphic Changes in Inner-Bluegrass Streams, Lexington, KY
Stream effects resulting from urbanization can be difficult to assess, especially without quantifiable measures. Agencies have spent billions of dollars rehabilitating streams to decrease these effects through Best Management Practice usage. This study’s goal was to establish monitored sites of urban effected streams, measuring their morphology and hydrology long term within Kentucky’s Inner-Bluegrass Region. Four initial stream reaches representing different riparian variables and flow regime in the same watershed were chosen and established over the summer of 2014. Reach selection was based on riparian vegetation and stream flow. Establishment of reaches included longitudinal profiles, pool and riffle cross-sections, and pebble counts. Rosgen classification was used to establish baseline conditions. As a part of the historical monitoring, documentation of urbanization, how urbanization influences streams’ geomorphic characteristics, and how those characteristics have changed. Once establishment was complete, a process of analyzing data, researching past stream movement through the landscape and classification, and comparing past and present geomorphic characteristics began. We assessed lateral stream movement using historical aerial photographs, along with measured erosion and changes to the stream channels. Stream reaches were more entrenched, straighter, and wider than historically, encouraging higher flow velocities and increasing the rate stream channels carve the landscape through erosional processes. As our research continues, we expect results to illustrate streams in the urban Inner-Bluegrass region function much differently than in the past. This knowledge will aid us in creating systems that work for the new hydrologic regime being delivered to urban stream sites.