Construction on the soil model at Coweeta Hydrologic Laboratory has begun! We will be using the model for a water and nutrient reaction and transport experiment to answer questions, such as: What is the dominant process (e.g., biogeochemical or hydrologic) for controlling export of nutrients from a hillslope? Under what conditions can we expect these controls to change? How does subsurface flow vary spatially along a hillslope?
The model was built for an experiment by John Hewlett and Alden Hibbert in 1963 to measure and describe nonstorm flow of water through soil along a hillslope to support base flow generation. (A picture of a similar, precursor soil model, used by John Hewlett and Lloyd Swift in 1961, is shown.) The model has not been used since then.
Kevin, Brian, and I surveyed the model—it looked good—and cleaned up leaf litter and debris around it. Then we constructed a hoop-house, a shelter made from lumber, rebar, PVC pipes, and a large plastic sheet (which weighed over 100 pounds!). Guy-ropes held it in place. The hoop-house is designed to keep out rain while letting in sunlight. Nobody was hurt during the field trip, although the hillslope was steep and slippery, the stairway narrow, and the weather wet.