EFFECT ON WATER QUALITY DUE TO DAM RESTORATION

Hammer Creek is part of the Conestoga River drainage basin in Lancaster County, Pennsylvania. In 1966, the Speedwell Forge Lake was artificially formed on this creek for recreational uses, but was drained in 2011 due to powerful storms which broke the dam behind it. Due to the popularity of Speedwell Forge Lake, dam reconstruction started in 2014 and will be completed in late 2015. This project captures the impact of ongoing construction on the water quality of Hammer Creek, compared to other reference streams in the same watershed.

Water quality data was collected downstream and upstream of dam construction on Hammer Creek, downstream of a previously dammed stream (Mill Creek), and at a nearby free flowing stream (Lititz Run). Hammer Creek, Mill Creek, and Lititz Run are part of the Conestoga River drainage basin, and all creeks have similar watersheds and average discharge. Riparian, Channel and Environmental (RCE) Inventories scores for all four streams are similar, suggesting that they should have similar biological and physical characteristics.

Temperature, dissolved oxygen, turbidity, total nitrogen, total phosphorus, and chemical oxygen demand measurements were collected weekly for 5 weeks. Water quality varied and fluctuated for all four streams over the weeks, partially due to summer precipitation patterns. Overall, dam reconstruction appears to only have a minor effect on Hammer Creek’s water quality, as only minimal difference in water quality parameters were observed upstream and downstream of the construction area. However, the water quality of the control streams varied from Hammer Creek, indicating that external factors may also be affecting water quality. Mill Creek’s variations in data could be explained by the previously constructed dam, and Lititz Run could have yielded fluctuating results due to a nearby waste-water treatment plant. Due to these four sites being located in a heavy agricultural area, the water quality in all streams may be affected by agricultural runoff more than from the dam restoration.