Distributed ecohydrological modelling to evaluate irrigation system performance in Sirsa district, India II: Impact of viable water management scenarios R. Singh a , R.K. Jhorar b , J.C. van Dam a, * , R.A. Feddes a a Department of Environmental Sciences, Wageningen University and Research Centre, P.O. Box 47, 6700 AA, Wageningen, The Netherlands b Department of Soil and Water Engineering, CCS Haryana Agricultural University, Hisar, Haryana, India Received 30 June 2005; received in revised form 16 March 2006; accepted 23 March 2006 Summary This study focuses on the identification of appropriate strategies to improve water management and productivity in an irrigated area of 4270 km 2 in India (Sirsa district). The field scale ecohydrological model SWAP in combination with field experiments, remote sensing and GIS has been applied in a distributed manner generating the required hydrological and biophys- ical variables to evaluate alternative water management scenarios at different spatial and tem- poral scales. Simulation results for the period 1991–2001 show that the water and salt limited crop pro- duction is 1.2–2.0 times higher than the actual recorded crop production. Improved crop hus- bandry in terms of improved crop varieties, timely sowing, better nutrient supply and more effective weed, pest and disease control, will increase crop yields and water productivity in Sirsa district. The scenario results further showed that reduction of seepage losses to 25– 30% of the total canal inflow and reallocation of 15% canal water inflow from the northern to the central canal commands will improve significantly the long term water productivity, halt the rising and declining groundwater levels, and decrease the salinization in Sirsa district.  c 2006 Elsevier B.V. All rights reserved. KEYWORDS Canal water distribution; Water productivity; Net groundwater recharge; Salinization; Regional scale; SWAP; Bhakra irrigation system Introduction Crop production in arid and semi-arid regions like Haryana State (India) is very limited without supplemental irrigation. The surface water supply diverted from high precipitation 0022-1694/$ - see front matter  c 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.jhydrol.2006.03.016 * Corresponding author. Tel.: +31 317 484825; fax: +31 317 484885. E-mail addresses: ranvir@iastate.edu (R. Singh), jhorar@yahoo. com (R.K. Jhorar), jos.vandam@wur.nl (J.C. van Dam), reinder. feddes@wur.nl (R.A. Feddes). Journal of Hydrology (2006) 329, 714– 723 available at www.sciencedirect.com journal homepage: www.elsevier.com/locate/jhydrol