Surface water quality patterns of White Clay Creek subwatersheds in Delaware and Pennsylvania
| Author(s) | Franks, Lydia G. | |
| Date Accessioned | 2025-03-13T16:05:11Z | |
| Date Available | 2025-03-13T16:05:11Z | |
| Publication Date | 2024 | |
| SWORD Update | 2025-03-05T17:01:18Z | |
| Abstract | Changes in land use and land cover significantly impact surface water quality. Excess nutrients, chloride, and rising water temperatures from anthropogenic activity contribute to declining aquatic ecosystems, however, best management practices (BMPs) and restoration approaches allow us to mitigate these impacts. Ongoing monitoring is necessary to observe changes in water quality resulting from water quality improvement efforts and refine management approaches. This study examined water quality trends across monitoring sites within small-scale drainages in the White Clay Creek watershed and relationships with land cover, as well as recommendations for structural and non-structural BMPs based on results. Using simple linear regression and the nonparametric Mann Kendall test for monotonic trends, nutrients, chloride, and water temperature were examined with land and agricultural cover, seasons, and streamflow. Water temperature across all study sites exceeded the seasonal criteria for cold water fishes. Chloride concentrations remained, primarily, below the target level of 50.0 mg/L. Nitrate was found to remain consistently near or above the 3.0 mg/L TMDL target for total nitrogen at all sites, with five-year medians ranging from 3.2 mg/L to 10.0 mg/L, with the highest nitrate concentrations observed at East Branch sites. Orthophosphate concentrations were most frequently seen below the 0.2 mg/L TMDL target level for total phosphorus and were found to have significantly decreased throughout the study period. Weak correlations were present between several land cover types and water quality parameters, while weak to strong correlations were found among various farming types and annual median nitrate concentrations. Statistically significant relationships were seen between nitrate in surface waters and percent forest cover of the areas drained, and between nitrate and multiple farm types including percent mushroom, row crop, meadow, pasture (horse/cattle), and fallow cover. The percentage of mushroom farm cover and annual median nitrate concentrations within drainage areas displayed a very strong, positive correlation. Moderate, positive correlations were found among percent row crop cover and percent animal pasture with annual median nitrate concentrations across drainage areas. Further investigation is warranted in the White Clay Creek at East Branch sites exhibiting chronically poor nitrate concentrations and increased monitoring is needed to explore trends more thoroughly. These findings provide a foundation for recommendations or further research, and while this study is only focused on specific components of a larger issue, intervention at local levels is needed to contribute to the overall health of the watershed. | |
| Advisor | Kauffman, Gerald J. | |
| Degree | M.S. | |
| Program | University of Delaware, Water Science and Policy Program | |
| Unique Identifier | 1511476146 | |
| URL | https://udspace.udel.edu/handle/19716/35912 | |
| Language | en | |
| Publisher | University of Delaware | |
| URI | https://www.proquest.com/pqdtlocal1006271/dissertations-theses/surface-water-quality-patterns-white-clay-creek/docview/3174361670/sem-2?accountid=10457 | |
| Keywords | Best management practices | |
| Keywords | Land cover | |
| Keywords | Surface water | |
| Keywords | Water temperature | |
| Keywords | Water quality | |
| Keywords | White Clay Creek | |
| Title | Surface water quality patterns of White Clay Creek subwatersheds in Delaware and Pennsylvania | |
| Type | Thesis |