Isha Ray & Serap Gül
Irrigation and Drainage Systems, 13: 361 – 383
Publication year: 1999


In much of the world, fresh water is scarce and getting scarcer. Growing populations, increasing industrialization, and environmental concerns have all put pressure on the water consumed by agriculture. This paper addresses the economic consequences of a permanent reduction in canal water for irrigation. Using detailed cost-of-cultivation data from the Gediz Basin, Turkey, the key questions are: How can farmers best respond to reduced surface water supplies? How can the canal management authorities best distribute this limited water? And,can the demand for water be reduced through input and output price policy? These questions are answered with scenario comparisons under several water availability,crop pattern, price and investment assumptions, for the short and medium time horizons.

Keeping productivity high and water use low requirescoordination between farmers and the water managementauthorities. The analysis shows that, in this region,farmers should keep all their land irrigated at loweryield levels, rather than reduce their cropped areas.The canal managers should opt for a short irrigationseason, rather than an extended season with long dryintervals. Sensitivity analysis on a range of pricesindicates that crop, rather than water prices, affectthe efficiency of water use. The scenarios areevaluated using AGWAT, a spreadsheet-based farm-budgetprogram which is simple and widely applicable. Therange of policy choices considered establishes aframework of analysis for other, potentiallywater-short basins, beyond the Gediz or Turkey.