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Omaha District plays important role in water quality management

Omaha District, U.S. Army Corps of Engineers
Published Aug. 6, 2020
Water Quality Management Branch's work boat

Water Quality Management Branch's work boat

Blue green algae on the shore of Lake Sakakawea, Van Hool, ND.

Blue green algae on the shore of Lake Sakakawea near Van Hook, ND. (courtesy photo)

Whether it is fishing, boating, swimming, or other types of water recreation the benefits of the Omaha District’s water quality management program affect outdoor enthusiasts in positive ways – these benefits even extend to water coming from the faucet. 

The Missouri River Basin and many of its many tributaries fall within the district’s area of operations, which include many Corps managed dams, lakes, rivers and reservoirs.Responsible environmental stewardship of these vital natural resources begins with sound water management.

The District’s water quality management program is a pro-active, year-round effort monitoring over 30 lakes, reservoirs, rivers and tributaries throughout six states: Nebraska, North and South Dakota, Wyoming, Montana and Colorado. 

The management of water resources by the Corps seeks to improve, restore, conserve, and protect the physical, chemical, and biological quality of the water for natural and human use.      

The success of the District’s water quality management program is attributed to a commitment to four functional categories: water quality monitoring and assessment; project water quality management planning; technical support; and program development and evaluation.

“The Corps impounds a lot of water, how we operate and manage our water projects can have a big impact on water quality,” said John Hargrave, water quality specialist with the District’s Water Control and Water Quality Section. “For example, pulling different amounts of water and where we pull the water from in the reservoir and how much goes down stream all affect water quality.”

Data collection is an important part of this program and Hargrave and his team are usually in the field taking water samples at various sites several times per month using sophisticated testing equipment. 

Water quality data is essential to understanding and effectively managing the aquatic resources of the District’s projects. Data samples provide the critical information needed to effectively develop, implement and evaluate water quality management activities at various project sites.

“For us, as an organization, it’s important to understand how our operations and projects, and more importantly how we manage them, affect surface water quality,” Hargrave said. “There are small and large towns that are drawing their drinking water from the Missouri River, so we need good quality control to keep things safe and to do the right thing as an agency.”

On a recent trip to Garrison Dam in North Dakota, Hargrave and his team checked several long-term fixed monitoring stations on Lake Sakakawea. Samples were taken across the water column from surface to bottom at one meter intervals including: temperature, dissolved oxygen, PH levels, chlorophyll, and turbidity among others. All data collected was recorded, stored and the appropriate paperwork completed. In addition, the data was shared with state and local agencies.  

“At Garrison, for example, throughout the profile of the water column one of the things we are looking for is how much cold water habitat is in the water as defined by the state of North Dakota’s water quality standards,” Hargrave said. “At the public swimming beaches we test for bacterial and viral contaminants in addition to various types of algae.”

For the first time this year, a new water quality model has been developed and is being implemented at Lake Zorinsky in Omaha. According to Brent Dinkel, a limnologist with the District’s Water Quality Section, the new model should improve water quality.

He explained that during the summer months at Lake Zorinsky there is a thermocline of two layers of water that don’t mix; colder at the bottom and warmer on top. Organic matter at the bottom uses up all of the oxygen resulting in sediment buildup, phosphorus, metals and other compounds which can lead to excessive algae growth. 

“We’ve basically simulated different ways to release water from the reservoir at Zorinsky - the model indicates that it should work,” Dinkel said. “We’re releasing low levels of water a little bit at a time throughout the summer in order to move the phosphorus and poor quality water out of the reservoir before it turns back over in the fall.”

Dinkel added that it will not be until the fall that he will know if implementing the new model was successful at improving the water quality at the lake. 

“I enjoy this job a lot, it’s what I’ve always dreamed of doing,” Dinkel said. “I like being out in the field and making a difference in the water quality of the lakes in the area and on the projects we manage.”    

The U.S. Army Corps of Engineers is one of the nation’s leading federal providers of outdoor recreation, managing over 400 lake and river projects across 43 states.