Effect of Historic Milldam Density on Current Water Quality Indicators in a Portion of the Chesapeake Bay Watershed

Suspended sediment, nitrogen, and phosphorus are a significant source of pollution in the Chesapeake Bay, and levels of these pollutants in the watershed’s streams and rivers are concerning. Traditional approaches to reducing sediment and nutrient loads have focused primarily on upland soil erosion, but often fail to include in-stream processes like bank erosion. It has recently been shown that in the North American Piedmont geographical region, historic sediment that accumulated behind milldams in the 18th and 19th centuries, referred to as legacy sediment, is an underestimated source of sediments in the Chesapeake Bay. Breached dams result in altered stream structures that exacerbate bank erosion and erosion of legacy sediment. In this study, I aimed to examine the relationship between historic milldam density in a watershed and the current water quality leaving the watershed. I expected to find positive correlations with watersheds with higher milldam densities having higher current levels of suspended sediment, total nitrogen, and total phosphorus. Watersheds were constructed using ArcMap software based on USGS stream gauge stations in Pennsylvania and Maryland in the Chesapeake Bay watershed. Milldam density for each of these watersheds was calculated as number of dams per hectare, and linear regression analyses were run for each of the water quality variables. No statistically significant results were found for the 14 studied watersheds. More research is needed to determine whether there is a relationship between historic milldam density and current water quality indicators

A Survey of Hydra Species in Selected South Central Pennsylvania Lakes

Species of the genus Hydra are freshwater invertebrates present in lentic ecosystems around the world. Research on the phylogeny and biogeography of the genus has identified four species groups. However, little work has been done on Hydra ecology during the last forty years, even though the freshwater habitats where they are found are often substantially impacted by human activities. Our project aimed to characterize the distribution of Hydra species in selected lakes in south central Pennsylvania. We sampled six lakes within Lancaster and Dauphin counties. Based on preliminary sampling of a lake on the Elizabethtown campus, we hypothesized that the species H. oligactis and H. vulgaris would be present in all locations. Plant material was gathered from lake bottoms near shore and examined for Hydra using stereoscopic microscopes. Hydra species were identified based on bud morphology and structure of nematocysts, and detection probabilities for each species were estimated using the program MARK. Hydra were found from all four species groups and at all six locations, although the lakes varied in size, dissolved oxygen levels, and whether an inflowing stream was present