THE EFFECT OF LAND COVER ON SEDIMENT QUALITY IN THE BLACK RIVER, OH

Anthropogenic activities within a watershed can create poor sediment quality in the receiving waters. The Black River, located in northeast Ohio, is well-suited to assess the effect of land cover on stream sediment quality because the upstream watershed is less developed compared to the downstream watershed where the Black River flows through the city of Elyria. According to the National Land Cover Database, the upstream watershed is approximately 1% medium and high intensity developed, 25% forested, and 59% agricultural land cover. Downstream, where the Black River flows through the city of Elyria, the watershed is approximately 31% medium and high intensity developed, 13% forested, and 10% agricultural land cover. The mud fraction of stream channel sediment was measured by X-ray fluorescence and shows that as developed land cover increases, Pb content also increases. In the upstream part of the watershed, having 1% medium and high intensity developed land cover, the average Pb content is 18 ± 7 ppm (n= 34). Within the city of Elyria, medium and high intensity developed land cover is 31% and the average Pb content is 54 ± 44 ppm (n= 14). Further downstream, the Black River cuts through the Berea Sandstone which contains a pyrite-rich layer at its base. This pyrite-rich layer contains 411 ± 5 ppm Pb. Within this reach of the Black River the average Pb content increases slightly to 62 ± 28 ppm (n= 23). Anthropogenic activities associated with developed land cover and naturally occurring sources result in higher Pb concentrations within the city of Elyria compared to the upstream part of the watershed. Characterizing how watershed land cover and natural sources contribute heavy metals to river sediment can aid in remediation design efforts to improve sediment quality in rivers.