Subtask 1.5 Identify and Characterize Saline Water Sources Entering the Pecos River

Although the Pecos Basin is highly saline, little information is available as to the saline water sources entering the river. The suspected sources include saline creeks, saline seeps (which may be aggravated by irrigation), and river seepage in upstream areas that may transport salts and halites to sediments beneath the river channel.

The goal of this Subtask is to identify the locations and the magnitude of saline water sources entering the Pecos River below Red Bluff Dam.

The first phase of this Subtask will develop of a literature review of existing reports about such topics as the geology, hydrology, soils, surface and subsurface saline water sources, and ground water quality of the Pecos Basin.

The second phase of this Subtask will identify saline water sources entering the river between Red Bluff Dam and the town of Girvin (about 150 river miles south of the dam) where significant saline inflow is believed to occur. Sources of saline water inflow will be identified by surveying streamflow salinity, pH and temperatures. Locations along the Pecos River where substantial changes in salinity, pH and temperature of the streamflow are noted will be considered as potential sites for saline inflow. Sources of water that will be examined include surface water from Red Bluff Dam, saline seeps, brackish and saline groundwater, and selected creeks and tributaries. Chemical markers and isotopes will be used to trace the origin and flow of water to these water bodies.

If the Pecos River flows over its banks, salts can be flushed into the river. This scenario has occurred in the Middle Rio Grande below Fort Quitman, and researchers suspect it may also take place in the lower reaches of the Pecos Basin. Project leaders hope to collect and analyze soil samples from the banks of the Pecos River between Girvin and Langtry to investigate these overflow issues.

Deliverables for this Subtask

A reconnaissance survey of saline water sources entering the Pecos below Red Bluff will be conducted.

Reports

  • TR-291: Reconnaissance Survey of Salt Sources and Loading into the Pecos River