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Stone and Robert's Run |
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Location, Logistics and AccessThis testbed consists of three watersheds-Benner, Stone and Robert’s Runs in the headwaters of West Branch Susquehanna River. These basins are located in northcentral PA, Clearfield County on lands managed by PA Bureau of Forestry and PA Game Commissions. We have had long-term cooperative agreements with these agencies since 1988 that allow us to access and study these watersheds. All are within 100 km of Penn State and served by gravel roads to stream gage sites. Winter access by 4WD truck is generally possible, but roads are not plowed for snow. No electric power is available at the research sites and line-of-sight radio communication is difficult due to the terrain.SettingThese three watersheds are part of EPA’s Long-Term Monitoring Project established to assess the impacts of the Clean Air Act on stream water chemistry in vulnerable forest ecosystems within the Mid-Appalachian region. Watersheds are all approximately 1000 ha with perennial first and second order streams. The streams are home to native brook trout populations and sculpins also occur in some streams. Terrain has not been glaciated and is moderately steep; average slopes are approximately 10-20%. The residual soils are derived from sandstone and shale and have relatively little buffering capacity. Streams likewise have relatively little buffering capacity, but Benner Run is the least acidic and Stone Run is the most acidic during runoff episodes. Stream water has relatively low total dissolved solids with conductivities generally less than 50 μS/cm. Suspended solids concentrations are extremely low, less than 100 NTU turbidity at high flows is common. Hydrology is dominated by rainfall events with winter snowfall representing 5-15% of precipitation depending upon the year. Infiltration capacity of the sandy to silty loam soils is very high and little overland flow occurs. Snow cover typically occurs for 1-2 months in winter. The basins are entirely forested with mixed deciduous tree species like oak, maple and cherry dominating. Some forest cutting has occurred in the past on these basins. Mean annual precipitation is approximately 120 cm. Mean annual air temperature is about 9 ◦C.Scientific InfrastructureAt the watershed sites, no facilities are available except for small gaging station sheds and climate stations. At Penn State University there are numerous offices and lab facilities, including a complete inorganic water chemistry laboratory with trained staff run by the Penn State Institutes of the Environment (PSIE) and Pennsylvania Water Resources Research Center. Field vehicles are available for project use from PSIE. Full library and computer services are also available along with other infrastructure typically found at a university.InstrumentationAt each watershed site a gaging station heated with propane gas has been established with an off-stream stilling well. Water level recorders with electronic data loggers and strip-chart recorder output are available. Battery operation (12V) of equipment is employed. Piping is set up to accommodate automatic water samplers in the streams. A non-recording precipitation gage with Alter wind shield is available in small openings near each stream gage. Streams are manually gaged and computed discharge is related to a staff gage elevation at each site to establish a rating curve. Rating curves and channels are very stable.Research InventoryResearch and monitoring began in 1988 at each site as part of the EPA Episodic Response Project. Since that time with a few gaps continuous streamflow data are available up to 2003. In 1988-90 streams were intensively sampled during stormflows and baseflows to evaluate impacts of episodic acidification and high dissolved aluminum concentrations on trout and sculpins. Since that time the basins have been operated as part of the EPA Long-Term Monitoring Project as described above with monthly grab sampling of the streams at the mouth of the watersheds. Complete cation and anion chemistry analysis of water samples has been obtained with relatively few data gaps from 1988 to 2003. Several short-term studies of water chemistry and aquatic ecosystems have been conducted by students on these watersheds over the past 15 years. Several data gaps that have occurred were due to changing EPA administrations and funding lapses.Scientific IssuesImpacts of reduced atmospheric emissions of pollutants on stream chemistry and aquatic ecosystems have been the primary issue addressed by operating this facility. Initial emphasis was placed upon reduction of sulfur emissions. Gradual decreases in stream sulfate and increases in ANC levels in streams have been noted over the past 15 years. Impacts of reduced nitrogen emissions will be the major issue for the future. Studies of fish populations in these streams have focused on defining lethal conditions during episodic acidification and the relative importance of groundwater refugia in the headwaters of these streams to preserve crticial biodiversity. Detailed studies have also been conducted on the importance of DON in the export of nitrogen by these streams and the fraction of nitrate in streams that can be attributed to direct atmospheric deposition. A long list of publications, theses and dissertations has resulted from all of the student and PI research on these watersheds.
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Susquehanna River Basin Hydrologic Observing System |
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