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eNews September 2018

NMSU Student Will Study Effects of Anticipated Climate Change on the Hydrology of Watersheds

By Catherine Ortega Klett, NM WRRI Program Manager

Khandaker Iftekharul Islam is a PhD student in Water Science and Management Program at NMSU, and a recipient of a 2018 NM WRRI Student Water Research Grant entitled: An Efficient Forecasting of Hydrologic Extremes Under Climate Change. The problem of water scarcity in the Southwest is expected to be exacerbated by a long-term continuance of global warming. A great deal of international effort has been expended in order to estimate the extent of future warming under various scenarios of projected increases in greenhouse gases. To this end, very complex numerical global climate models have been developed and used to run simulations of the likely future climate. Khandaker will make use of some of these climate scenarios, adjusted for the local context by dynamic downscaling of the results of the general circulation models, to estimate the resulting hydrologic effects on watersheds. In this effort, he will be assisted by his faculty adviser, Dr. Christopher Brown of the Water Science and Management Program (Affiliated), and the Department of Geography.

The plan of action for estimating the hydrologic impact on various local watersheds caused by future warming will be to first select, on the basis of accuracy when applied to a particular watershed, from a set of four available hydrologic models. These models attempt to simulate such relevant watershed behavior as stream hydrology and sediment transport, overland flow, channel routing, saturation infiltration, runoff, and flood forecasting. The assessment of accuracy will be carried out for a particular watershed by comparing the model predictions against actual hydrologic data for the study area. Then, having established the best available hydrologic model for a given watershed, it will be used to simulate the expected hydrologic response to a selected future climate change scenario.

It is hoped that this study will provide some insight into the likely long-term effects of climate change on the hydrological behavior of local watersheds. In particular, it may help to identify the most potentially severe water scarcity zones within watersheds, as well as provide better estimates of the frequency and intensity of extreme events like flooding and droughts and of the associated changes in overall water quality. Given the warmer and dryer conditions in the Southwest in recent decades, and the resulting decrease in precipitation and snowpack, water demand already exceeds supply in New Mexico in most years. An expected doubling in the population by the next half-century will put even more pressure on our limited water resources. Accordingly, there is a definite need to develop further skill in the art and science of forecasting the possible effects of future warming on our water supply. It is in this context that the present study should make a welcome contribution.

Khandaker expects to complete this study by 2019. He plans to present a poster of his research at the upcoming NM WRRI 63rd Annual New Mexico Water Conference that will take place at the Las Cruces Convention Center on October 17-18, 2018.

Khandaker is originally from Dhaka, Bangladesh. He graduated with a BS in civil engineering from Rajshahi University of Engineering and Technology (RUET). He received his MS in civil and environmental engineering from Chalmers University of Technology in Sweden. Khandaker is eager to work to improve existing hydrologic models. He says, “I am dedicated to craft, and my goal is to become a University researcher or work in a research laboratory.”