Rain generated surface runoff water quality and quantity monitoring of bottomland hardwood forests: A review of designs, challenges, and research needs

Abstract The Mississippi River Basin has been extensively altered with levees, channelization, and agricultural land conversion. Much of the disturbed land was historically bottomland hardwood forests (BHF) and wetlands. As knowledge about sediment and nutrient nonpoint pollution has expanded, several wetland restoration and water quality monitoring programs have been developed through the United States Department of Agriculture Natural Resources and Conservation (e.g., the Agricultural Conservation Easement Program, Environmental Quality Incentive Program, and Edge‐of‐Field (EOF) Water Quality Monitoring Activity). Traditional water quality monitoring includes the use of pressure transducers, piezometers, and grab samples. The EOF water quality monitoring system generally focuses on agricultural inputs and uses non‐contact measurement sensors. EOF monitoring stations include a flume, water sampler, and an ultrasonic level sensor. This system can monitor water quality in most flow conditions; however, BHF wetlands have more complex flow requiring a modification of the standard EOF station. By using a laser Doppler velocimeter (e.g., LaserFlow, Teledyne ISCO) in place of the flume and ultrasonic sensor, stage and velocity can be calculated in bidirectional flow at various speeds and levels. Nonetheless, more research is required into alternative instrumentation in complex heterogeneous hydrology found in BHFs.