Climate Change impacts on water resources and utilities Lia van Wesenbeeck, ACWFS, VU University Joint work with Fayez A. Abdulla, Hani Abu Qdais, (JUST), Wim van Veen, Ben Sonneveld, and Max Merbis (ACWFS)

Overview of presentation The problem Predicting climate change for the JRB The Water Economy Model Scenario specification Outcomes Discussion

The problem Climate change is likely to affect water availability across the globe Also the Jordan River Basin (JRB) is going to be affected The region already experiences major challenges related to water Hence, important questions are: How will climate change affect rainfall? What is the impact of predicted rainfall patterns on Agriculture Human consumption Water resources

Predicting climate change for the JRB Global Circulation Models (GCMs) are used to project the climate change on global and continental levels. But: has low resolution (100–500 km). downscaling techniques have been developed to build relationships between GCMs output and subgrid climate variables precipitation and temperature

Downscaling and extrapolation Earlier work by Prof Abdulla focused on downscaling GCM prediction to the Yarmouk river basin Using different scenarios In this paper, these downscaled results were taken as point of departure for extrapolation to the Jordan River Basin

Extrapolation of Yarmouk forecasts Downscaled climate change scenarios daily data covering the period 1 January 1981- 31 December, 2100 23 stations in the Yarmouk Basin. Daily precipitation data were aggregated spatially into six districts that fall within the Yarmouk Basin temporally into six cohorts of 20 consecutive years of annual rainfall data Relative changes were calculated: over 40 (average of 2000-2020 minus 2040-2060) and 80 (average of 2000-2020 minus 2080-2100) years were calculated And plotted against a South-North gradient. A linear function using relative changes as dependent and the North coordinate as dependent variable was used to predict the precipitation changes for all districts in the JRB.

Scenario specification

The Water Economy Model Developed within SIDA-sponsored project Partners: American University of Beirut Al Quds University, Palestine Territories Arab Center for Studies of Arid Zones and Dry Lands (ACSAD) Jordan University of Science and Technology (JUST) Amsterdam Centre for World Food Studies (ACWFS)

Model dimensions 48 districts (s) 26 two-weekly time steps (t) Daily rainfall calibration and simulation 5 layers (l) 3 pollutants and pure water (h)

Schematic representation

Water quality Representation of pollutants Salinity Biological Oxygen Demand (BOD) Nitrate Pollutants dissolved in water Also for pollutants, balances hold!

Modelling Impact on agriculture Farm response functions

Scenario consequences: less run-off to the river

Scenario consequences: less extraction from the rivers

Scenario consequences: less recharge

Scenario consequences: limited changes in household demand Change relative to baseline Baseline water demand

Impact on agricultural revenues

Discussion: initial shock and system response

Summarizing the outcomes of the scenario the reduction in rainfall is a major shock partly compensated by reduced evaporation (300 mcm less) river flows are substantially lower and, hence, also river extraction the immediate effects on human demand remain relatively limited however, recharge is very negatively affected (not sustainable) also outflow to Dead Sea substantially lower (20 mcm)

Thank you

Mathematical representation Extremely rich model! Yet, mathematical representation is simple and transparent: Extraction output Return flow consumer rainfall Natural inflow Consumer demand Available for natural outflow Extraction demand