Surface Water Studies
Stream system boundaries in Oklahoma are defined by watersheds identified through 11-unit Hydrologic Unit Codes developed by the U.S. Geological Survey. Primarily for purposes related to water use and administration, the Red River Basin is divided into 18 stream systems while the Arkansas River Basin is divided into 17 systems, depending upon the watersheds of streams and rivers that contribute precipitation run-off to those streams. Some stream systems are further divided into subsystems.
Hydrologic investigations of surface waters are dependent upon data gathered at streamflow and water quality discharge monitoring stations operated throughout the state by the U.S. Geological Survey and the Oklahoma Water Resources Board. Data obtained from the statewide streamflow monitoring network can be used for many purposes, including flood prediction, drought monitoring, development of reservoir operation plans, and other related planning activities. Due to limitations on the number of streamflow monitoring sites available in Oklahoma, streamflow modeling is becoming an increasingly important tool to estimate streamflow values between monitoring stations and in watersheds deficient of monitoring sites.
Characterization of the watershed is necessary to determine factors affecting streamflow. Variation of slope over a watershed, land use, precipitation, stream size and gradient, amount of base flow from groundwater, water use, and other hydrologic characteristics significantly influence the amount of flow in a stream or river.
The interaction between surface and groundwaters has recently become a vital component of many OWRB hydrologic investigations. To develop realistic management options for our water supplies, we must understand this interaction and how development of one resource ultimately impacts the other.
Surface Water Allocation
The OWRB has developed a new support analysis tool that will facilitate adjudication and effective management of water rights in Oklahoma.
Stream Water Allocation Modeling
OWRB implemented the Stream Water Allocation Modeling Program in 2009 to support the appropriation, allocation, distribution, and management of stream water in the state. The program is a pioneer statewide initiative in the United States for the assessment of both water availability and reliability as well as a supporting tool for the adjudication and effective management of water rights in Oklahoma. Models are being used by OWRB staff to:
What are allocation models?
Allocation models are computer applications that contain data about the river-basin hydrology and active water rights in the system (curently over 60 years of data), capturing the essential statistical characteristics of the hydrologic system and accounting for the probable range of its future hydrology. The models are constructed using a network-flow algorithm in Microsoft Excel® called the Central Resource Allocation Model (CRAM) which simulates management of the water resources under a priority-based water allocation system. Water is distributed in the system on a monthly basis and demands or "water rights" are supplied based upon a selected management scenario. Results from a simulation include estimates of water availability (before and after appropriation), flow and content at reservoirs, amount and frequency of water shortages, and interference of water rights. The OWRB has developed software applications to effectively display the results from the models through statistics, graphs, tables, and maps that show the detail of the spatial and temporal resolution of the model.
The Stream Water Allocation Modeling Program will have completed models for approximately 70% of the State by the end of June 2014. The models will have the capability of assisting more than 2,300 existing water rights and new permit applications in these areas.
Fig. 1 Stream water allocation models completed for stream systems in Oklahoma. Enlarged version of map
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Page last updated: August 28, 2014