1. Corresponding author: International Water Management Institute (IWMI) Regional Office for South Asia, ICRISAT, Patancheru 502 324 andhra Pradesh, India. Fax: 91-40-2324-1239. E-mail: j.ensink@cgiar.org
2. IWMI, Regional Office for Pakistan, Central Asia and the Middle East, 12 km Multan Road, howk Thokar Niaz Baig, 53700 Lahore, Pakistan. E-mail: t.mahmood@cgiar.org
3. IWMI, PO Box 2075, Colombo, Sri Lanka. E-mail: w.van-der-hoek@cgiar.org, l.raschid@cgiar.org, f.amerasinghe@cgiar.org