7409 - Laserfiche WebLink

Home Browse Search

TITLE /I PROGRAM SUMMARJES 53 approval of plans. Prior to project implementation, activity plans and associated environmental analyses are conducted. Public involvement is encouraged throughout the process. BLM administers 48 million acres of public lands in the Colorado River Basin above Imperial Dam, 36 percent of the Basin's total area. Approximately 8 million acres of BLM-administered lands in the basin contain saline soils. Salt concentrations are highest in saline geologic settings, usually marine shales, where annual precipitation averages less than 12 inches. Salts enter tributaries of the Colorado River from surface runoff, erosion, and ground water flows (non point sources), and from point sources such as saline springs, spoilpiles at mines, and oil and gas production sites. Most salt contributions to the Colorado River occur from nonpoint sources. Nonpolnt Source Control Controlling salinity in surface runofffrom rangelands is closely related to controlling soil erosion. Vegetation cover is usually the most important management variable influencing runoff and erosion rates on rangelands. Vegetation management, either indirectly through the design and implementation of livestock grazing plans or directly through vegetation manipulation, is an important erosion and salinity control technique. Proper land use, including grazing systems that incorporate increased cover, appropriate seasons of use, and stream protection as objectives, is BLM's preferred method of achieving salinity control. However, on the most highly saline land, maximum potential cover is often too low to provide meaningful control of surface runoff and erosion. In situations where the watershed condition is so severely degraded that recovery will be inefficient under normal land management practices, mechanical land treatments and structural alternatives may be the most effective salinity control. Technical land treatments involve soil tillage techniques such as contour furrowing, ripping, and pitting. Common structural techniques include rangeland dikes, retention plugs, retention and detention reservoirs, and gully plugs. Point Source Control Many saline water point sources exist on public lands in the form of either wells or springs. Several wells have been plugged, and other flowing wells will be plugged as the situation warrants. BLM has developed and currently maintains a water inventory to identify and characterize water uses and respective sources on public lands. Saline springs will be identified through the program. Control of saline springs will be analyzed through BLM's planning process, with major sources brought to the attention of Reclamation. An example of this is the Sinbad Valley Unit in western Colorado. In September 1986, all advance planning activities for the Sinbad Valley Unit were transferred to Reclamation. Salinity Control Accomplishments Over the past few years, several measures have been undertaken in Colorado, Wyoming, and Utah to prevent nearly 8,000 tons of salt from entering the river system. Inventories and planning work has been initiated in six of the Basin States. u.s. Geological Survey The mission of the U.S. Geological Survey (USGS), Water Resources Division iliJ to provide information about and interpretive appraisal of the nation's water resources. Through district offices, located in each State of the Colorado River Basin, USGS personnel maintain and develop cooperative hydrologic investigations with local, State, and other Federal agencies. These investigations typically are local in scope, and compiement the regional and national investigations and research supported by USGS Federal funds.