Semanchik, Kristie, Department of Biology, Bucknell University, 1 Dent Drive, Lewisburg, PA, 17837, ks065@bucknell.edu; McTammany, Matthew, Department of Biology, Bucknell University, 1 Dent Drive, Lewisburg, PA, 17837, mmctamma@bucknell.edu.
Local to the West Branch of the Susquehanna, Turtle Creek is an agricultural stream that runs through a heterogeneous landscape of open farmlands, riparian buffers, and forested areas. Pennsylvania’s Department of Environmental Protection (DEP) has begun restoration projects to reduce nutrient and sediment inputs and to improve Turtle Creek’s stream health. DEP’s projects along Turtle Creek include bank stabilization and riparian buffers. Riparian vegetation typically serves as a buffer between streams and farmlands, as it can filter and absorb excess nutrients from manure and fertilizer before entering the waterway. Riparian vegetation also shades streams and reduces water temperature, which is critical to stream health. However, due to the “farm-by-farm” approach used in most stream restoration programs, these projects add to the heterogeneity of vegetation along Turtle Creek, as the development of riparian vegetation is primarily up to individual property owners. This study aims to evaluate the influence of riparian vegetation on stream temperature by comparing reaches along this heterogeneous stream system. We monitored 18 sites, 14 on Turtle Creek’s main stem and 4 on tributaries to Turtle Creek. The main stem reaches were divided into 5 categories based on riparian land cover (open development, open agriculture, new riparian, old riparian, and remnant forest). HOBO Pendant temperature loggers were set to collect water temperature hourly at each site from June 8th, 2023 to August 1st, 2023. Water samples were collected on a bi-weekly basis to measure concentrations of nutrients and major ions in the streams. Temperature increased as the stream moved from upstream to downstream, with a sharp increase in temperature as the stream flowed from its headwaters into agricultural areas of the valley floor. Long reaches with Remnant Forests produced a cooling effect on the stream between monitoring sites. Stream temperature is influenced by a multitude of factors such as water source, vegetation density, air temperature, and urbanization. While these factors play a pivotal role in regulating water temperature, regional climate is the most important natural factor affecting stream temperature. Therefore, as the climate continues to warm, maintaining riparian buffers and remnant forests could be critical to mitigate rising stream temperature.
Stream Temperature, Riparian Buffers,
Heterogeneous Landscape