Systematization of water allocation systems: an engineering approach

摘要

The allocation of water resources is typically accomplished within the framework ofwater allocation systems (WAS). In general, a WAS sets priorities, applies rules, andorganizes responses to a range of water allocation scenarios. This research presents acomprehensive study of water allocation strategies and provides a conceptual framework ofprinciples and guidelines for designing, assessing, implementing and supporting WAS. Thevoluminous compilation of international treaties and conventions, interstate compacts,intrastate administrative documentation, and scientific/engineering literature was researchedin order to identify different water allocation strategies and mechanisms. From this analysiseight fundamental areas of WAS were identified: water rights, determination of waterallotment, administrative systems, reservoir storage considerations, system reliability,multiple uses, instream flow requirements, and drought management. The systematicscrutiny of these eight areas at the international, interstate, and intrastate levels defined theconceptual framework for assessing WAS. The Texas experience with regard to its WaterAvailability Modeling system is also reviewed with particular emphasis on the application ofthe Water Rights Analysis Package (WRAP) model in supporting water allocation efforts.The Lower Rio Grande WAS was used as a case study to demonstrate how the principlespresented in the conceptual framework can be used to assess water allocation issues andidentify alternative strategies. Three WRAP simulation studies utilizing several componentsof the conceptual framework were performed in order to assess the Lower Rio Grande WAS.The simulations focused on three of the major water allocation issues of the Texas RioGrande: reallocation among uses, instream flow requirements, and drought management.The simulations showed several deficiencies in the Lower Rio Grande WAS, particularlyregarding the size of the domestic-municipal-industrial (DMI) reserve and its effect on thereliability of other uses. The simulation results suggest that water from the DMI can be liberated to be used by irrigators and to support environmental flows without affecting thereliability to municipal users. Several strategies were proposed that can potentially improvethe overall efficiency of the system. Nonetheless, implementing new strategies and waterallocation policies in the Lower Rio Grande WAS would require considerable changes inregulation policies.