Computer models play important roles in environmental and water resources planning and management. However, the number and complexity of available software packages -- both public domain and proprietary -- can be overwhelming for anyone attempting to sort through the maze of models and to understand which ones might be useful for a particular application. This reference critically evaluates the extremely wide range of water management modelling software to help water managers, engineers, and scientists identify, select, and acquire the optimal software program for their particular modeling needs. Covers general-purpose software packages that deal with water management models. Considers packages that focus on specific models for demand forecasting and balancing supply with demand; water distribution systems; ground water; watershed runoff; stream hydraulics; river and reservoir water quality; reservoir/river system operation. Features a Model Inventory Appendix covering in depth the details of 37 generalized water management models with a proven record of successful application. For engineers, scientists, planners, and managers involved with waste and wastewater management, drainage and stormwater management, municipal and industrial water districts, irrigation and flood control districts.