USGS Stream Denitrification Study

Recent U.S. Geological Survey research has found that natural biochemical processes in water moving back and forth between a stream and its underlying sediment were significant in removing nitrate from streams in the Illinois River basin, one of the world’s most intensively farmed regions.

The USGS study in a nitrogen-polluted stream found that the flow of streamwater through a very thin zone of sediment enhances chemical reactions that decrease nitrate delivery to coastal areas where nitrogen fuels formation of hypoxic "dead zones." 

Beneath all streams and rivers is a shallow layer of sediment that is permeated by water exchange across the sediment surface. This boundary between the world of earth and water in streams is referred to by scientists as the "hyporheic" zone, from Greek words meaning "under the flow." The hyporheic zone can be thought of as the stream's "skin," since it serves vital functions such as the removal of dissolved and particulate contaminants being transported by the stream.

Previous research has established under laboratory conditions that hyporheic flow should be critical to sparking reactions that improve stream water quality, but field studies have generally been unable to reveal the contribution of hyporheic flow to decreasing the flow of contaminants to sensitive downstream waters.

This field study determined that a very thin skin, a mere four centimeters (1.6 in.) of sediment, was effective in removing nitrate from streams of the Illinois River basin during late summer. The crucial investigative approach was labeling in-stream nitrate with an isotopic tracer that could be followed at very fine scales in the sediment and simultaneously tracked for kilometers downstream.

The study scientists found that hyporheic flow increased nitrate removal by renewing the supply of dissolved organic carbon and nitrate to specialized bacteria in the sediment that performed denitrification, a reaction that converts dissolved nitrate to gaseous nitrogen and so removes nitrate permanently from flowing water.

The top four centimeters of sediment had the greatest abundance of denitrifying bacteria, in addition to the highest levels of hyporheic flow. Sediment properties in this thin layer were also conducive to the formation of oxygen-free micro zones that are required for the reaction to take place.

The study was published in the October 2013 edition of Water Resources Research. The findings were presented December 11 at the fall meeting of the American Geophysical Union.

source: U.S. Geological Survey

NOAA Columbia-Snake River Salmon BiOp Fails

On August 2, 2011, U.S. District Court Judge James Redden ruled that the National Oceanic and Atmospheric Administration (NOAA) Fisheries Service failed for the third time in ten years to produce a legal and scientifically adequate plan to protect imperiled Columbia-Snake River salmon from extinction.

Fishing and conservation groups, the state of Oregon, the Nez Perce Tribe, and the Spokane Tribe opposed the federal biological opinion, or BiOp, in court.

This is the third time Judge Redden has found a BiOp for the Columbia-Snake Basin inadequate and illegal. Today, salmon populations are critically low, lingering near just 1 percent of their historic levels.

In finding the current plan’s heavy reliance on unidentified and uncertain habitat actions illegal, the court wrote: “Coupled with the significant uncertainty surrounding the reliability of NOAA Fisheries' habitat methodologies, the evidence that habitat actions are falling behind schedule, and that benefits are not accruing as promised, NOAA Fisheries' approach to these issues is neither cautious nor rational.”

Endangered Snake River salmon and steelhead tackle a migration like no other salmon on earth. Some swim more than 900 miles and climb almost 7,000 feet to reach their spawning grounds, scaling eight dams along the way.

source: wildsalmon.org

Urban Waters Federal Partnership Pilot Programs

The United States Department of the Interior recently announced the creation of the Urban Waters Federal Partnership (UWFP), a federal union of 11 agencies.

Agencies of the Urban Waters Federal Partnership include the Environmental Protection Agency, Department of the Interior, United States Department of Agriculture, Corporation for National and Community Service, Centers for Disease Control and Prevention, Department of Commerce/Economic Development Administration, Department of Commerce/National Oceanic and Atmospheric Administration, Army Corps of Engineers, Department of Transportation, Housing and Urban Development, and National Institute of Environmental Health Sciences.

Efforts of the partnership will focus on stimulating regional and local economies, creating local jobs, improving quality of life, and other goals in communities across the country.

UWFP will focus its initial efforts on seven pilot locations including the Patapsco Watershed (Maryland), Anacostia Watershed (Washington DC/Maryland), Bronx & Harlem River Watersheds (New York), South Platte River in Denver (Colorado), Los Angeles River Watershed (California), Lake Pontchartrain Area (New Orleans, La.) and the Northwest Indiana Area

For more information, visit: http://www.urbanwaters.gov

source: Department of the Interior press release

Colorado River Basin Water Use Study

An April 2011 report from the National Parks Conservation Association analyzes the impacts of water management in the Colorado River Basin and five national parks that lie along the Colorado River and its tributaries.

According to the report, water management has altered the natural state of the river, including the long-term presence of major dams and non-native species, and changes in water flow in the system.

National parks examined in the study include Grand Canyon National Park, Glen Canyon National Recreation Area, Canyonlands National Park, Dinosaur National Monument, and Black Canyon of the Gunnison National Park.

The report cites several factors which affect the rivers in these parks:

• Dams along the Colorado River have fundamentally changed ecological and environmental processes in these parks by  destroying natural habitats in some areas, creating highly unnatural flow regimes, trapping sediments that are critical for building and maintaining aquatic and riparian habitats and altering natural water temperatures that foster native fish communities.
• Reintroducing more natural water flows in the rivers can protect park resources. In addition, any further alterations to the natural flow of the river must not compromise these treasured parks, which receive a total of more than 8.5 visitors annually. . Recent proposals to divert water from the River for municipal and agricultural uses would likely be detrimental to the parks. 
• Climate change scenarios predict the western United States will become drier and warmer, which increases the likelihood that the volume of water in the river annually will decrease and releases from reservoirs like Lake Powell will be reduced.
• Non-native fish have been introduced; causing issues for native species through predatory and competitive behavior and the non-native tamarisk has altered the river channel, further restricting river flows.

The report outlines steps that can be taken to reverse or mitigate some of the challenges facing the river, including:

• Changes to dam operations to reduce impacts on endangered species and other resources, which would have relatively minor effects on hydropower revenues.
• Climate change research to clearly understand and ensure that its effects on the River are taken into account for all future policies and decisions impacting water flow in the river.
• Additional research on costs and benefits of restoring more natural flows so that the value of the parks along the River can be properly assessed.

To view a full copy of the report, please visit: http://www.npca.org/cpr/colorado_river_basin/

source: National Parks Conservation Association