Long-term trends in climate and hydrology in an agricultural headwater watershed of central Pennsylvania, USA.
Climate change has emerged as a key issue facing agriculture and water resources in the US. Long-term (1968-2012) temperature, precipitation and streamflow data from a small (7.3 km2) watershed in east-central Pennsylvania was used to examine climatic and hydrologic trends in the context of recent climate change. Annual mean temperatures increased 0.38°C per decade, which led to an expansion of the growing season, and increased evapotranspiration (+37.1 mm per decade). Additionally, mean annual precipitation also increased while the overall change in streamflow decreased. In general, the findings suggest some challenges for producers and water resource managers with regards to increased rainfall and runoff. However, some changes such as an enhanced growing season can be viewed as a positive effect.