Determining the wind drag coefficient in hydrodynamic modelling of a shallow, fetch-limited water system : a case study in Friesland, The Netherlands

A well-known effect of high sustained winds from one direction is wind set-up. To accurately represent the wind effects on inland water systems by means of a hydrodynamic model is difficult, especially in fetch-limited water bodies. There is limited information available for practical applications under these conditions. The transmission of momentum between wind and water is generally formulated as a shear stress term, scaled with the wind drag coefficient. This study examined whether, and to what extent, the wind drag coefficient in a shallow, fetch-limited, inland water system varied spatially and/ or with the wind characteristics. Moreover, this study examined whether the wind drag coefficient should vary for these dependencies to improve hydrodynamic model predictions of water levels significantly.