Royal Dutch Meteorological Institute; Ministery Of Infrastructure And The Environment

Publications, presentations and other activities
Wetland versus open water evaporation: an analysis and literature review
by Y. Mohamed (Unesco IHE), W. Bastiaanssen (WaterWatch), H. Savenije (TU Delft), B. van den Hurk (KNMI), C. Finlaysson (IWMI Sri Lanka)
<p>Is the total evaporation from a wetland surface (including: open water evaporation, plant transpiration and wet/dry soil evaporation) similar, lower, or higher than evaporation from an open water surface under the same climatic conditions? This question has been a subject of long debate; the literature does not show a consensus. In this paper we contribute to the discussion in two steps: First, we present a theoretical analysis of evaporation from a wetland with emergent vegetation (Ea) versus open water evaporation (Ew) by applying the Penman-Monteith equation to identical climate input data, but with different biophysical characteristics of each surface. Second, we assess the variability of measured Ea/Ew through a literature review of selected wetlands around the globe.<br /> We demonstrate that the ratio Ea/Ew is site-specific, and a function of the biophysical properties of the wetland surface, which can also undergo temporal variability depending on local hydro-climate conditions. Second, we demonstrate that the Penman-Monteith model provides a suitable theoretical basis to interpret Ea/Ew variations. This implies that the assumption of wetland evaporation to behave similar to open water bodies is not correct. This has significant implications for the total water consumption and water allocation to wetlands in river basin management.</p>
Bibliographic data
Mohamed, Y., W. Bastiaanssen, H. Savenije, B. van den Hurk and C. Finlaysson, Wetland versus open water evaporation: an analysis and literature review
Phys. Chem. Earth, 2012, 47, 114-121, doi:10.1016/j.pce.2011.08.005.
Abstract (html)