Conjunctive surface water and groundwater management: A new framework for strategic decision-making

Conjunctive use of water, or the optimized use and storage of surface water and groundwater, has become increasingly recognized over the past decades as an approach that facilitates efficient management of water resources. Recent research on conjunctive management primarily relies on economic evaluations or numeric modeling for specific regions however, less research has focused on variables such as water laws and government institutions that affect water management policy options. There is a lack of consensus on its appropriate implementation, and no single document provides key parameters and standards for successful policies and programs of conjunctive use.Accordingly, the goal of this research was to identify and evaluate essential factors in conjunctive management. Objectives to accomplish this goal first involved evaluation of quantitative and qualitative components and their relationships in conjunctive management. Based on the evaluation results, a new decision framework for strategically understanding and designing a conjunctive program was created to support consideration and decisions concerning conjunctive management options. Finally, the research goal of determining key factors that support viable conjunctive management was demonstrated through application of the framework in the Rio Grande basin.Based on the research results concerning quantitative and qualitative factors, a conjunctive strategy decision framework was created to support improvements in understanding, designing, and implementing conjunctive strategies. A new conceptual model, minimum criteria, and a decision matrix of conjunctive components and external factors comprised the framework. The conceptual model incorporated seven major components of regional, surface water, and groundwater systems, ecosystems, economic/financial issues, legal/institutional frameworks, and social/stakeholder input. These components established the foundation of the framework.Key criteria necessary to design a conjunctive strategy were developed from analysis of the major components. The criteria were compiled for each component and used as a basis for evaluation of conjunctive goals. The matrix detailed the relationships between major components and external factors, including parameters identified through evaluation of previous conjunctive models, studies, and programs.The conjunctive decision framework was prepared to support decisions concerning conjunctive strategies. Development of the framework was formed with the knowledge that water user groups and water professionals do not necessarily share an understanding of conjunctive use and its benefits and limitations. To test its efficacy, the framework's criteria base was applied to the Rio Grande basin of the southwestern United States. The basin was selected based on its unique geographical, social, and ecological features and the water-stressed conditions varying from floods to droughts that the basin has periodically experienced. Within the basin, the region selected for application of the framework was the lower Rio Grande valley. Existing technical reports and water management planning documents were utilized. The majority of criteria were addressed and integrated with existing information, thus theoretically minimizing program design costs. However, review of the reports and documents showed that planning teams in the region have yet to fully realize conjunctive goals, strategies, standards, and an efficient approach to achieve an operational and successful conjunctive program. The framework can provide a path for achieving the overall goal of improved water management in the region. (Abstract shortened by UMI.)...