Irrigation’s health and environmental impacts are closely linked. For health, the negative impacts of irrigation development can be mitigated through better design and operation of new and existing systems, especially through multiple uses of irrigation water. For the environment, the impacts of irrigation can be positive but they more usually are negative (Goldsmith and Hildyard 1992; Dougherty and Hall 1995; Petermann 1996). Better identification and understanding of the externalities related to irrigation during design or redesign and management of irrigation systems can enhance the positive impacts and mitigate the negative ones (Bolton 1992).