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ARS Home » Northeast Area » University Park, Pennsylvania » Pasture Systems & Watershed Management Research » Research » Publications at this Location » Publication #314973
Title: Long-term trends in climate, hydrology, and water quality in a central Pennsylvania watershed: more grazing?

Author
item Kleinman, Peter
item LU, HAIMING - Nanjing Research Institute For Agriculture
item Elkin, Kyle
item Buda, Anthony
item Collick, Amy
item Folmar, Gordon
item Bryant, Ray

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 7/25/2018
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Adapting agriculture and water resource management to climate change requires local knowledge of what change is occurring. 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, hydrologic, and water quality trends in the context of recent climate change. Over the four decade period of observation, annual mean temperatures increased 0.38°C per decade, which led to increased evapotranspiration (+37.1 mm per decade). Although mean annual precipitation also increased, the overall effect of higher evapotranspiration resulted in decreased streamflow. The lengths of warm season, growing season and summer season increased by 2.82, 2.83 and 4.00 days per decade respectively. The length of the cold season decreased at a fairly uniform rate of -0.74 days per decade, and the number of frost days also decreased at a rate of -3.64 days per decade. Seasonally, total precipitation during the growing season (mid-April to mid-October) was 34% higher than during non-growing season with June being the wettest and February being the driest months. Significantly wetter Octobers combined with the trend for later arrival of the first autumn freeze suggests opportunities for an extended fall grazing season on cool season grasses. The average length of periods of low streamflow, represented by the maximum consecutive days during which mean streamflow was lower than the 10th percentile, was 16 days and ranged from 0 to 70 days. This indicator of drought increased at an average rate of 1.9 days per decade over the study period. Hotter and drier summers suggest an opportunity for including warm season grasses in the grazing rotation. Nitrate losses decreased and phosphate losses increased in this predominantly row cropped landscape. 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.