Surface Water Studies

OWRB Studies: An Overview

Accurate technical and scientific information is required to make sound planning and management decisions concerning the state's water resources. In this regard, Water Board staff conduct and update studies of stream systems and groundwater basins, then present results in various OWRB technical reports.

Traditionally, the primary focus of hydrologic investigations is to determine the amount of water in storage to efficiently allocate water rights among the state's many water users. Today, the scope of these studies has broadened to address pertinent water management issues, such as groundwater-surface water interaction, impacts of water withdrawal on water quality, maintaining instream flow, drought management, basin and watershed characterization, water supply, and local water and associated economic needs.

Components of Hydrologic Investigations

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

Hydrologic studies facilitate the adjudication of water rights by determining water availability in each stream system. Hydrologic investigations have been completed on all of the state's stream systems (23 in the Red River Basin and 26 in the Arkansas River Basin); updates of these studies are underway.

The OWRB also conducts or supervises studies of reservoir yield that are critical to determining the amount of water supply available for municipalities, rural water districts, industries and other water users. Yield, an estimate of the amount of water that can be dependably appropriated from a specific source, is determined by inflow, evaporation and related factors.

Current Studies

• The OWRB and U.S. Bureau of Reclamation continue their cooperative assessment of the North Fork of the Red River watershed, including the Lugert-Altus Reservoir. Bureau of Reclamation staff have been conducting assessments of potential sources and management options to augment the water supply in Lugert-Altus Reservoir. Future funding will be sought to begin development of groundwater and surface water models to assist the OWRB and Bureau of Reclamation in understanding the effects of groundwater development on stream water flows with the North Fork of the Red River watershed.
• Geotechnical work, in conjunction with the U.S. Army Corps of Engineers continues at the proposed Mangum Reservoir site in southwestern Oklahoma