Riparian Zone
Prepared by Jonathan Angier, Environmental Quality Laboratory, Beltsville, Maryland
Riparian zones typically consist of vegetated corridors adjacent to stream channels. These areas are considered effective natural barriers, which prevent agricultural pollution from being exported and contaminating the larger ecosystem. Part of the OPE3 study consists of determining how well the riparian zone functions at removing agricultural nutrients (nitrogen and phosphorus) and pesticides.
The OPE3 riparian zone contains a small 1st-order stream that is fed predominantly by groundwater originating in the adjacent agricultural field. The stream is instrumented with five sampling stations fitted with weirs, which are used to measure stream flow. Flow data is collected at each of the weirs in 15 minute intervals. There are approximately 170 piezometers (wells that are only open at discrete 8-inch intervals beneath the surface) throughout the riparian zone. These are used to evaluate subsurface groundwater movement, and for collecting samples. About 60 of these piezometers are fitted with pressure transducers that collect continuous water level data at 10 minute intervals. Sap flow sensors have been placed in five trees within the riparian zone, to take direct measurements of tree sap flow during the growing season.
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