Review of Decision Support Systems and Allocation Models for Integrated Water Resources Management Focusing on Joint Water Quantity-Quality

Integrated Water Resources Management (IWRM) is increasingly important due to water scarcity, population growth, climate change, and deterioration of resource quality. IWRM requires analytical tools such as automated models and interactive systems, which may be difficult to implement, particularly in developing countries. This paper reviews existing basin-level models and decision support systems (DSSs) for public water allocation, provides application examples, and systematically reviews the literature on concepts arising from the definition of IWRM. Two environmental concepts considered in this review, water quantity-quality management and sustainability, were the most frequently used in revised allocation models, most of these in spatial decision support systems (SDSS). These automated systems presented, in most cases, three advantages: a well-developed friendly interface enabling application of more than one model, allowance for different decision criteria and restrictions together with the analysis of scenarios/sensitivity, and tight coupling and connection to spatial databases. This greatly facilitates and enhances their use by decision makers and stakeholders, favoring an environmentally sustainable management of water resources. Findings showed few models that combined the requirement of sustainable management maximizing economic well-being together with equality. Overall, most of the tools developed are prescriptive (optimization), nonlinear and deterministic models, which were not available through any DSS. In addition, allocation modeling that considers aspects of quantity-quality combined with economic optimization was almost entirely developed in the last decade of the analyzed period. Implementation of IWRM needs a process with participation of all the stakeholders involved, supported by hydrological and economic models integrated and available through DSS.