SWAT-G, a New Glacier Routine for the Hydrological Model SWAT
Abstract
The hydrological model SWAT is a recognized and widely used tool in water resources management and the reproduction of the hydrological cycle of river basins all over the world. In this context, SWAT is also commonly used in alpine and high-mountainous regions, which are often characterized by a substantial fraction of glaciated areas. However, SWAT does not consider glaciers and its underlying processes in a reasonable way. A corresponding mass balance routine is even completely missing, so that this crucial water storage is completely neglected in the application. The consideration of the glacier component is essential for the investigation of climate change-induced changes of the hydrological cycle in high alpine areas. Here, we present a novel version of SWAT, SWAT-G, considering both a glacier mass balance module and a glacier retreat procedure based on the delta-h approach, first presented by Huss et. al (2010). The new version is a first step towards a more justifiable applicability of SWAT in high alpine catchments. In particular, it aims to increase the credibility of SWAT applications in the context of climate impact studies.
We demonstrate how the routine is technically implemented, what additional steps in the model setup are required and how to transfer the approach to SWAT+. The empirical method is especially suitable for large catchments covering a multitude of glaciers. Our first tests focus on the glaciated upper Martelltal basin (South Tyrol/Italy) which is located in the Italian Eastern Alps. We evaluate the capabilities of the new glacier routine in a multi-objective approach by validating the glacier mass balance changes, areal retreat and thickness changes, which are now explicitly estimated in SWAT. Thus, remote sensing products, such as snow cover from MODIS and Sentinel-2 or glacier outlines from the Randolph Glacier Inventory (RGI) are used to supplement available ground-truth data. In addition, a cross-evaluation of the module is conducted by assessing different water balance components from the standard SWAT model, which is further calibrated with discharge. References Huss, M., Jouvet, G., Farinotti, D., and Bauder, A.: Future high-mountain hydrology: a new parameterization of glacier retreat, Hydrol. Earth Syst. Sci., 14, 815-829, https://doi.org/10.5194/hess-14-815-2010, 2010.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2022
- Bibcode:
- 2022AGUFM.H22O1016S