HR: 0830h
AN: H51C-1068    [PDF]
TI: Temperature Patterns and Cooling Through a Short Step-Pool Reach in a Headwater Stream, Dry Creek, Idaho
AU: * Rothwell, E L
EM: ericrothwell@mail.boisestate.edu
AF: Geoscience,Boise State University, 1910 University Drive, Boise, ID 83725 United States
AU: McNamara, J P
EM: jmcnamara@boisestate.edu
AF: Geoscience,Boise State University, 1910 University Drive, Boise, ID 83725 United States
AU: Luce, C H
EM: cluce@fs.fed.us
AF: Rocky Mountain Research Station, USDA Forest Service, 316 E.Myrtle, Boise, ID 83702 United States
AU: Chandler, D
EM: dchandle@mendel.usu.edu
AF: Plants Soils and Biometrics, Utah State Univerisity, 2300 Old Main Hill, Logan, UT 84322 United States
AB: Stream temperature is a controlling variable of stream ecology and can be influenced by hyporheic exchange. The extent of the role hyporheic exchange plays in small streams is not well understood because few studies have been able to close the energy balance for the study reaches. The objectives of this study are to quantify energy exchange associated with hyporheic flow and bed conduction, to balance a heat budget by including all major fluxes of heat energy through the reach and to compare resulting temperature predictions with measured values in a small a riffle-step pool sequence. The study is being conducted in the Dry Creek Experimental Watershed near Boise, Idaho. The stream flows through an upland desert steppe environment, but is heavily shaded by growth directly adjacent to the stream. During the field campaign the stream maintained a typical flow of 0.01m3/s and was steadily losing flow to the subsurface, with some flow returning through hyporheic exchange. Loss of flow to groundwater was assumed to be negligible for this short reach. Stream temperatures cooled as much as 0.7$\deg$C through the short, 5m, study reach. Net radiation is the dominant inflow of energy to the reach, with evaporation, hyporheic exchange and bed conduction combining to result in a net cooling.
DE: 0350 Pressure, density, and temperature
SC: Hydrology [H]
MN: 2003 Fall Meeting