Water Rights Analysis Package (WRAP)
Content Table
Introduction
The Water Rights Analysis Package (WRAP) is a modeling system that simulates management of the water resources of a river basin or multiple-basin region under a priority-based water allocation system (WURBS 2005a). It is designed to find a compromise among the multiple uses and users of the water resources.
WRAP was developed in Texas after the adoption of water rights permit system in the state during the 1970s and 1980s. A research project for optimization of reservoir operations in Texas carried out by the Texas A&M University needed a generalized water rights analysis model. The first WRAP model originated then, named Texas A&M University Water Rights Analysis Program (TAMUWRAP). Since then, numerous versions of the model have been elaborated.
Application
WRAP is applied to evaluate hydrologic and institutional water availability and reliability to satisfy water supply diversions, reservoir storage, environmental instream flow requirements, and hydroelectric energy generation. Advanced options allow simulations for flood control, reservoir operations and salinity tracking (WURBS 2005b).
The function of WRAP is to study the performance of a river/reservoir system for which the water is allocated among users based on specified priorities. The streamflow changes that occur due to diversion and instream flow requirements, or reservoir storage, are taken into account and water balance computations are carried out. Generally, the modeling process consists of two phases. Since the simulation is based on a hypothetical repetition of historical hydrology, the first step is to develop sequences of monthly naturalized streamflows. Naturalized streamflows represent historical hydrology without the effects of human interference, i.e. water use and storage. Having the input data of natural streamflows, the second step in the modeling is to simulate the water allocation according to the priority order. It is assumed that the full amounts of all permitted diversions are withdrawn, provided that sufficient water is available from streamflow and/or specified reservoir storage capacity. WRAP simulates the rights/reservoir/river system, and estimates the regulated and unappropriated streamflows. A postprocessor program organizes and summarizes the WRAP simulation results by a variety of user-specified tables and reliability indices, such as period and volume reliability and flow-frequency relationships (WURBS 2005a).
The advantages of the programme are:
- integrated basin-wide approach
- free public use, wide scope of application
- user-friendly features
- generalized, yet flexible
The challenges related to the application of WRAP are:
- preparation of the input data describing hydrology
- adjustments necessary, if applied outside the U.S. (metric system)
Related Articles
References
Wurbs, R. A. (2005a): Water Rights Analysis Package (WRAP) Modeling System Reference Manual.
Wurbs, R. A. (2005b): Water Rights Analysis Package (WRAP) Modeling System Users Manual.
