HR: 0830h
AN: H21C-02    [Abstracts]
TI: Explore a Fine Resolution MM5 for Reservoir Temperature Forecasting
AU: * Mao, Q
EM: qmao@tva.gov
AU: Mueller, S F
EM: sfmueller@tva.gov
AB: TVA's three nuclear plants and some fossil plants rely on reservoir water for cooling. When weather is hot during summer, variable meteorological conditions such as wind and cloud cover often affect reservoir water and make its temperature prediction particularly challenging. A critical point is occasionally reached when a decision must be made on whether to derate a generating unit to comply with thermal discharge restrictions. The decision to derate can depend on differences of a few tenths of a degree in the water temperature prediction. Predicted reservoir temperatures for cooling of a TVA nuclear plant, for example, is produced by hydrodynamic models with input meteorological condition for the entire lake approximated by a National Weather Service Forecast Office (NWSFO) forecast issued for the closest airport to the water discharge location. One of the potential areas for improving reservoir temperature prediction is the non-homogeneous meteorological forcing over the body of water. A high resolution PSU/NCAR MM5 model was explored for improving reservoir temperature forecasting. Three summer periods representing extremely hot weather conditions were selected for MM5 simulations over the cooling water source of one TVA nuclear plant. The MM5 was configured with five concentric modeling domains. Grid resolution ranged from 27 km for the coarsest to 0.3 km for the finest modeling domain. Model results from the finest resolution domain were evaluated and analyzed with observations from a meteorological tower of the plant and reservoir temperature profiles from permanent buoys near the plant. Preliminary results indicate that the fine resolution MM5 model is capable of simulating large air temperature variations resulting from extreme weather events. The model can also simulate non-homogeneous weather conditions and produce different wind patterns across the reservoir that can affect water temperature through wind induced turbulent mixing. Detailed modeling results and analyses will be presented at the joint assembly.
DE: 1818 Evapotranspiration
DE: 1845 Limnology
DE: 1857 Reservoirs (surface)
DE: 1860 Runoff and streamflow
DE: 1871 Surface water quality
SC: Hydrology [H]
MN: 2005 Joint Assembly