THE IMPACT OF STORM ON THERMAL TRANSPORT WITHIN THE HYPORHEIC ZONE OF A LOW GRADIENT THIRD-ORDER SAND AND GRAVEL BEDDED STREAM

The impacts of temperature on stream and hyporheic environments are far reaching, and one event that affects temperature in this environment is a storm event. The goal of this study was to evaluate the impacts of storm events on thermal transport in the hyporheic zone (HZ) and stream stage of a low gradient sand and gravel bedded stream. Wells were installed at two different sites in the Little Kickapoo Creek, and temperature loggers were positioned at different depths to record substrate temperatures. The stream stage and stream temperatures were also recorded. It was observed after analyzing the thermal data that the after storm thermal response in the stream and HZ depends on the temperature of the incoming storm water runoff, the pre-storm temperature trend, diurnal heating, and upwelling groundwater temperature. Baseflow stream temperature trend depends on diurnal temperature but lags behind the diurnal temperature trend. There is a drop in stream temperature and a spike in substrate temperature during a storm response in the summer and the converse of this observation occurs during the autumn. The rate of thermal response dampens with increasing substrate depth during the summer and it increases with increasing depth during the autumn. The thermal response in the stream and at 30 cm below the surface lagged the storm event by ~30minutes and at the 60 cm depth lagged the storm by ~1hour in the summer, whereas, in the autumn the 30cm response lagged behind the storm by ~1hour and the stream lagged behind by ~2hours and the 60cm lag were quite erratic between the wells.