1a.Objectives (from AD-416):
Quantify surface and subsurface hydrologic effects on runoff chemical transport and determine the scaling relationship between laboratory derived chemical loading parameters to field scale processes.
1b.Approach (from AD-416):
Conduct chemical loading experiments on a multi-segment recirculating flume which has hydrologic controls for surface and subsurface water to identify the dominant hydrologic process affecting chemical transport and conduct a stream injection study and compare results with the laboratory flume study to derive the scaling relationship between lab and field results.
A specially constructed flume that has the capability to simulate all the hydrologic components of a flowing ditch has been constructed. This flume has four 5-m segments and each segment has independent control for the subsurface hydrology. Experiments are underway to quantify chemical transport processes in the flume. The first experiment is to quantify the transport of a reactive (phosphorus) and a conservative (bromide) tracer as the subsurface hydrology of the streambed is changed from seepage to saturation and drainage. The outcome of this research is the improved understanding on how chemicals or pollutants are transported in agricultural drainage ditches.