Preliminary results: Implementing the Seasonal Water Yield model (INVEST NAT-CAP) for three different watersheds across the Americas.

SCORDO FACUNDO; VANESA PERILLO; THOMAS MICHAEL LAVENDER; SEITZ CARINA; ANDREA BRENDEL

Gaming

Workshop; GLEON 18 Lunz & Gaming, Austria 4 - 8 July 2016 GLEON 18 Poster Session; 2016

University of Vienna

Global climate change is expected to have different impacts across the Americas. Understanding seasonal water flows in watersheds, in particular the partitioning between quick flow (occurring during or shortly after rain events) and base flow (slow release flow occurring during dry weather), improves our ability to more accurately assess the risk of flooding or drought events within a watershed. The objective of this study is to evaluate three geographically distinct watersheds across the Americas (Muskoka River (Canada), Winooski River (USA) and Alto Senguer River (Argentina) for risk of droughts or flooding. To answer this question, the INVEST NAT-CAP ?Seasonal Water Yield model? (http://www.naturalcapitalproject.org/invest) was used to calculate quick flow and base flow in each watershed under current climatic conditions. Finally, the proportion of total flow (QF + BF) that was QF and BF was calculated using the ArcGIS 10.2 raster calculator tool. Our hypothesis is that a watershed with a lower quick flow (QF) proportion [QFp = (QF / (QF + BF)] compared to its base flow (BF) proportion [BFp = (BF / (QF + BF)], in current conditions is more resilient to changes in future conditions (QFp < BFp = more resilient). Those watersheds that have a similar QFp and BFp could be facing two different problems. Watersheds with high QF and BF will be threatened by floods while those with low QF and BF, will be threatened by drought. The results in this study show that the Winooski watershed, despite having high QF values, has a lower QFp versus BFp. Thus, it has a low risk of water driven problems (floods or droughts). The Muskoka watershed presented high QFp, especially in the area surrounding water bodies. This watershed could be facing flooding risk if precipitation increases in this zone, as is predicted by the IPCC models. On the contrary, the Senguer watershed, despite having low values of QF, presented the largest area with high QFp. Most of the precipitation quickly turns into QF or is evapotranspirated, with little precipitation becoming BF. This watershed could be facing drought issues if precipitation decreases and the temperatures increase in this area, as is predicted by the IPCC models.