CGRG Bibliography of Canadian Geomorphology
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Author : Carlaw, S.M.; Kouwen, N.; and Soulis, E.D.
Date : 2000.
Title : The significance of soil moisture in flood forecasting.
Publication : Annual Scientific Meeting, Canadian Geophysical Union, Banff, Alberta, May 23-27, 2000.
Issue : Abstract.
Page(s) :
Abstract
The WATFLOOD distributed hydrologic model started out as a single event flood forecasting model. Since 1972, it has developed into a continuous simulation model which has been run on various watersheds in Canada and abroad. WATFLOOD is a distributed hydrologic model which uses gridded meteorological data to calculate streamflow hydrographs at selected points throughout the watershed. In 1996, WATFLOOD was selected to participate as a flood forecasting model to be evaluated within 2 international projects based in Europe: the Mesoscale Alpine Programme (MAP) and Runoff and Atmospheric Processes for Flood Hazard Forecasting and Control (RAPHAEL). In the general framework of MAP, specialists from atmospheric and hydrological sciences are cooperating to develop advanced methods for forecasting natural events having high social impact, such as intense rainfall and related floods (RAPHAEL proposal, January 1997). The programme included a multi-year preparatory phase, followed by a 13-month observing period with a 3-month real-time intensive field campaign (15 August – 15 November 1999), and will be concluded with a two-year evaluation phase (MAP Science Plan, 98/6). RAPHAEL is an independent, yet related project and was a precursor to the MAP field campaign. The same study areas were used for RAPHAEL and MAP, but the RAPHAEL project used historical data sets to calibrate the models and test their validity. Both projects involve the one-way coupling of atmospheric and hydrological models for improved flood prediction and the assessment of the weather forecast. This stems from the fact that the atmosphere and land surfaces together are a heavily coupled system. On one hand, the moisture content and other soil properties determine the runoff production in response to atmospheric precipitation. On the other hand, the land surface provides fluxes of moisture, heat and momentum for the atmosphere that affect general circulation. Both these factors are highly relevant to regional weather and flood forecasting and are substantially affected by complex topography (MAP Design Proposal, 98/6). Soil moisture is a key state variable shared by both WATFLOOD and the Mesoscale Compressible Community Model (MC2) regional atmospheric model. The key to a successful coupling is to match the soil moisture budget in both models. This poster shows preliminary comparisons between measured and calculated soil moistures. Measured values were taken during the MAP field campaign and the BOREAS study, and calculated values are made using WATFLOOD, using input from MC2 for the MAP study, and conventional inputs for BOREAS. Observed and computed upper zone storage in a grassy field in Claro, Switzerland. Data courtesy of M.Zappa and J.Gurtz, ETHZ.
Bibliography of Canadian Geomorphology