Determinants of collective action on the local commons: a model with evidence from Mexico

I develop a model of cooperation in small irrigation systems. I give conditions under which an equalizing redistribution of wealth increases the level of equilibrium cooperation, but also show that some redistributions that increase inequality can also increase cooperation. The distributive rule, a combination of arrangements for maintenance-cost sharing and water allocation, also affects the cooperation level. I estimate statistical models of cooperation for three maintenance indicators using field data from a study of Mexican irrigation societies. Social heterogeneity and landholding inequality are significantly associated with lower maintenance. Distributive rules that allocate water proportionally to landholding size likewise reduce maintenance. (C) 2000 Elsevier Science B.V. All rights reserved JEL classification: D70; O12; O13; O17; Q25.