Author(s): Steven F. Daly
Linked Author(s): Steven F. Daly
Keywords: No Keywords
Abstract: The water temperature of a river at any point reflects how the upstream watershed responds to heat transfer with the environment. The ability to model this response provides a way to forecast future river water temperatures, which could be an important part of an ice forecasting program. This paper presents a model of the watershed response. In the model the overall environmental heat transfer is calculated based on two terms: one linearly dependent on the difference between the water and air temperatures, and one independent of the air temperature. The response of the watershed is determined by analyzing the past records of air and water temperature. From these records, monthly or seasonal response coefficients for the watershed are determined. Forecasts of future air temperature, along with the known water temperature at the time of the forecast, are used to forecast water temperature. Water temperature can be forecast for any future date; however, in practice the accuracy is limited by the current limitations of air temperature forecasts. The model is applied to the Ohio River, and results are shown as hindcasts of water temperature based on the actual recorded air temperatures, and hindcasts of "likely ice periods" based on the actual recorded data. The model can be used to forecast likely ice periods in large and small watersheds, is designed to be used with real-time water temperature measurements and is particularly useful for forecasting tributary water temperatures as boundary conditions for more elaborate models.
Year: 1988