Journey to Improve Water Quality in Powers Lake

Laura Fleming

Abstract

Outbreaks of blue-green algae in Powers Lake, a 1,616-acre natural lake, created an emergent call to action in the 1990’s from the community of Powers Lake, North Dakota, USA. Ongoing community action and funding both federal and local continue to improve water quality in Powers Lake. The Powers Lake Watershed Committee received three 319 federal grants and matched federal funding with local funding.   A 2001 water analysis measured Powers Lake as “hyper-eutrophic” and the watershed assessment specified the lake received an annual phosphorus load of 11,564 pounds. Significant reductions in nutrient loads entering the lake and cycling within the lake were necessary. Improving water quality at Powers Lake requires preventing nutrient pollution from entering the lake and removing sediment with an overabundance of nutrients from the lake. Farmers and ranchers within the watershed are preventing pollution from entering the lake with conservation practices. PLWC is removing sediment with an overabundance of nutrients from the lake via hydraulic dredging. Water quality continues to improve during the last 20 years.

Two Goals to Improve Water Quality

Improving water quality in a natural 1,616-acre freshwater lake is an enormous undertaking. The complexities of preventing and eliminating pollution are immense. Reaching two main goals was necessary to improve water quality at Powers Lake. Goal one was preventing pollution from entering the lake from the watershed which drains approximately 44,458 acres of primarily agricultural lands. Goal two was reducing nutrient cycling within the lake by removing sediments via dredging.

Powers Lake is located on the edge of the City of Powers Lake, North Dakota where the south end of town meets the lake. Historically, Powers Lake was of high recreational value and a natural resource to the community and known as one of North Dakota’s finest lakes for recreation and fishing and gathering.

Problems of Blue-Green Algae

In the 1980’s and 1990’s water quality deteriorated and the lake was frequently afflicted with blue-green algae blooms and fish kills. Blue-green algae, also called cyanobacteria consumes oxygen in the water. Anoxic conditions kill fish, create health hazards, and contaminate water. As a result of the blue-green blooms, the recreational value of Powers Lake plummeted, and fewer and fewer people gathered or recreated there.

Powers Lake Watershed Committee Formed

In 1998, the local community recognized the importance of Powers Lake and formed the Powers Lake Watershed Committee (PLWC) who initiated the complex project to improve water quality in Powers Lake. The committee was comprised of volunteers, educators, and representatives the City of Powers Lake and Mountrail and Burke counties including Soil Conservation District (SCD) and National Resources Conservation Service (NRCS) offices.

Watershed Assessment, Funding and Conservation Practices

Over the years, the community harnessed the talents and contributions of many individuals and organizations. They initiated a 2001 watershed assessment with Agricultural NonPoint Source (AGNPS) modeling. In 2003, they received the first of three 319 Federal grants, hired a Watershed Coordinator and began working with farmers and ranchers to implement conservation practices.

After the conservation practices significantly reduced nutrient load entering the lake, PLWC turned their attention to reducing the nutrient recycling within the lake. They pursued more funding and expertise to address the overload of nutrients within the lake.

The Powers Lake Watershed Committee received Federal 319 grants of the Clean Water Act in 2003, 2011 and 2016. The grants require a 60/40 matching from local funding. Remarkably, Powers Lake area residents, agricultural producers, and state and local folks met the challenge and matched federal funding with local funding, (cash and in-kind services) much of it through volunteer labor. The project also received a grant in 2017 from the North Dakota Outdoor Heritage Fund to assist with the cost of dredging operations.

Findings

In 1999, with assistance from the North Dakota Department of Health (NDDH) Division of Water Quality, PLWC initiated a watershed assessment and AGNPS model, which was completed in 2001. The assessment included monitoring water quality, compiling an inventory of current land use practices, and generating pollution estimates using the Agricultural NonPoint Source (AGNPS) model. AGNPS is a computer model used to predict nonpoint source pollutant loading within watersheds. The watershed assessment and AGNPS model recommended watershed restoration actions, pollutant reduction goals and outlined specific activities for accomplishing the goals and provided a method for evaluating progress.

The AGNPS modeling indicated that Powers Lake received an annual phosphorus load of 11,564 pounds with 6,339 pounds from external sources and 5,225 pounds from internal sources (nutrient cycling).The assessment report determined that for Powers Lake to meet State Water Quality Standards, it needed to achieve a 75% reduction of the nutrient load entering the lake, and a 50% reduction in the internal (nutrient cycling) nutrient load within the lake. Water sample findings through 2001 revealed the primary impairments to recreation and aquatic life in the lake were caused by excessive nutrient loadings, specifically, high levels of nutrients (especially phosphorous) and low dissolved oxygen levels.

Phosphorus is an essential element for plant life and a common ingredient of agricultural fertilizers, manure, and organic wastes. Excessive phosphorus levels accelerate eutrophication which occurred when the lake was overloaded with nutrients causing blue-green algae growth and depletion of dissolved oxygen. Powers Lake water analysis showed “hyper-eutrophic” which means poor water quality and extremely high growth of noxious surface scums of blue-green algae. As a result, the North Dakota Department of Health (NDDH) added Powers Lake to its 2002 Clean Water Act (CWA) section 303(d) list as fully supporting, but threatened, for the lake’s recreation and aquatic life designated uses.

Preventing Pollution from Entering the Lake

In 2002, the local citizens become increasingly aware of the deteriorated water quality and the loss of recreational value and a natural resource. In 2002, the community applied for a Section 319 NonPoint Source Pollution grant from the State to improve the water quality of Powers Lake. North Dakota, EPA’s Section 319 Non-Point Source (NPS) Pollution Management Program provides cost-sharing for watershed restoration projects in North Dakota including Powers Lake. The projects treat entire watersheds through the promotion of sustainable agricultural and sound land management practices.

In 2002, the Powers Lake Watershed Project (PLWC) was created with assistance from the Burke and Mountrail County NRCS, Burke and Mountrail County Soil Conservation District, US Fish and Wildlife Service, North Dakota Natural Resource Trust, and the North Dakota Game and Fish Department. Partnering with the different agencies brought more people working toward the common goal of improving water quality in the lake. They helped implement more conservation practices. Powers Lake Watershed Project developed a list of tasks designed to reduce the amount of phosphorous loading entering the lake.

They recommended implementing Best Management Practices (BMP) for Non-Point Agricultural pollution prevention.

In May 2003, the U.S. Environmental Protection Agency awarded the first grant on a 60/40 matching basis. The federal funds were matched by local funds (cash and in-kind services) from agricultural producers, PLWC, and state and local stakeholders. The Mountrail County Soil Conservation District (SCD) provided administrative services for the grant. In January 2004, a Watershed Coordinator was hired.

The Mountrail County Soil Conservation District SCD served as the administrative and fiscal agent for the project. Powers Lake Watershed Project hired staff to develop BMP contracts for agricultural producers and deliver technical assistance. Project staff worked closely with partners at the federal, state, and local level to support the project. North Dakota Department of Health (NDDH) provided oversight for project management, developed the quality assurance project plan, conducted water quality monitoring training, and helped to develop education activities.

Agriculture Producers Implement Best Management Practices

Agriculture production is the economic foundation of the Powers Lake area communities and agricultural pollution was a significant source of pollution entering Powers Lake. Much to their credit, agricultural producers changed practices and adopted Best Management Practices BMP’s for soil and water conservation to reduce the nutrient loads entering the lake. Agricultural producers, farmers and ranchers made changes that significantly reduced the amount of sediment entering Powers Lake.  

Since the project began, there is a great change in the landscape. Beginning in 2003, many farmers switched to no-till or minimum till and fewer acres were fallowed across the watershed. Farmers reduced the quantity of fertilizers applied by balancing crop nutritional needs with necessary application rates.

Fortunately for the project, many ranchers in the watershed agreed to be part of the solution to reduce unwanted runoff. They made changes and adjusted their operations. They installed wells, pipelines, tanks, fencing, grass seedings, and grazing rotations. One rancher installed a waste management system to divert clean water around a feedlot and hold manure water within the feedlot until it settles out before being spread across fields as fertilizer.

Powers Lake Watershed Project also worked closely with the North Dakota Game & Fish Department, the North Dakota Natural Resources Trust, and the U.S. Fish and Wildlife Service, who provided technical and financial assistance to create or restore 9 wetlands, seed in grass, and protect the shorelines and riparian areas. In addition, local Soil Conservation District (SCD) staff worked cooperatively with local Natural Resources Conservation Service (NRCS) personnel to identify and tap all available funding assistance programs.

The data indicates the watershed conservation activities are effective at preventing nutrients from entering the lake through erosion and runoff. The Powers Lake community continues to make improvements to the watershed to reduce nutrients flowing into the lake. The changes resulted in far fewer nutrients flowing down the watershed into Powers Lake.

 

 

Watershed Conservation Activities BMP

Measurement

Res-Till 329A

19,575 acres

Nutrient Management

12,103 acres

Past/Hay planting

1,246 acres

Cover Crops

530 acres

Pipelines

32,320 linear feet

Fence

66,349 linear feet

Wells

7

Tanks

23

Grazing Systems

5,577 acres

Waste Mngt Sys

1

Tree plantings

37,040 linear feet

Well Decommissioning

1

Urban stormwater

1

Grass Easement

1,487 acres

Wetlands created

9

 

Water Sample Findings

The Trophic State Index (TSI) classification system is used to evaluate water quality levels based on the quantity of biological productivity occurring in the water. Carlson’s Trophic State Index (TSI) measures transparency or turbidity (using Secchi disk depth recordings), chlorophyll-a concentrations (algal biomass), and total phosphorus levels.

The water quality measurements between 2001 and 2009 indicate that TSI scores are improving. The average TSI score for chlorophyll a in 2009 was 53.24, which met the improvement criteria of a total maximum daily load (TMDL) target of 55.02, However, the phosphorus TSI scores, remained high and held steady at 85, which is rated as “hyper-eutrophic” range. The likely cause was phosphorus within the lake continually cycling from the lake’s bottom sediments.

Seeking Solutions to Remove Nutrient Loading Within Lake

In 2008, PLWC sought solutions on how to reduce the internal nutrient cycling which was feeding blue-green algae blooms. The internal nutrients are attached to the sediment and primarily composed of phosphorus. Houston Engineering Inc. was hired and completed the Powers Lake Nutrient Management Alternatives report in October 2009. They recommended removing lake sediments to reduce the internal nutrient cycling via dredging as the best remediation method.

The 2008 report from Houston Engineering Inc. also measured the depth of the lake and found the average depth to be 5.6 feet. They recommended removing 3.6 feet of sediment to increase the average depth to 9.2 feet. Dredging improves water quality in two ways. First, it removes the detrimental sources of internal nutrients and adds depth to the lake which reduces wind energy turbulence and lessens the stirring of bottom sediments. Hydraulic dredging removes bottom sediment and pumps a mixture of sediment and water, called slurry, from the bottom of the lake through a pipeline to another location.

Funding to Remove Nutrient Load in Powers Lake

The data also indicated that internal lake nutrient cycling is now the primary cause of algae production. In 2011, PLWC received a second grant of CWA section 319 funds and again matched the federal grant with local funding. This funding supported dredging to reduce internal nutrient cycling and increasing lake depths by remove bottom sediments via dredging.

City of Powers Lake Purchases SRS Crisafulli Dredge to Remove Nutrient Load

In spring 2014, PLWC considered buying a large dredge capable of quickly removing sediment, but the high purchase price and labor costs (millions of dollars) deemed it impractical. In 2015, PLWC chose a Crisafulli Rotomite 6000 dredge, priced at $300,000 as the most practical solution.

In 2014 while attending the North Dakota Rural Water Association 2014 Conference, Kenny MacDonald, Powers Lake Watershed Coordinator, met Troy Fercho, Sales Manager from SRS Crisafulli, Inc., a hydraulic dredge manufacturer located in Glendive, Montana. Troy invited Kenny and PLWC to Glendive for a spring demonstration of dredging.

In spring of 2015, members of PLWC traveled to Montana to see a demonstration and test dredges at a local lake. By July 2015, the City of Powers Lake purchased a Crisafulli Rotomite 6000. Kenny MacDonald, Powers Lake Watershed Project Coordinator has been operating the dredge for 5 seasons and discharging the sediment to a holding area near the lake. Locals reuse the sediment, which is rich soil containing nutrients, for land application, gardens and landscaping.

As of 2019, 50,900 cubic yards of sediment and 80,273 pounds of phosphorus and 32,020 pounds of nitrogen have been dredged out of the lake. The goal is to continuously remove sediment.  

 

 

Measuring Water Quality Improvements

Determining the restoration progress of a eutrophic lake is not easy. Many factors affect lake ecosystems and processes. There are a variety of conditions and components driving the chemical processes of a waterbody. Climate effects like temperature, precipitation, and wind can change which processes become primary drivers. The amount of ice and duration of ice cover and timing of run-off influence nutrient levels in the lake.

The winter and summer cycles and nutrient peaks can obscure the fact that Powers Lake water quality continues to improve. During some springs and before ice-off, nutrient spikes are detected while during other springs and before ice-off, nutrient spikes are not detected. It is important to realize that those weather-related spikes are lower than the overall averages of nutrients in the years’ 2001 through 2009. As Kenny MacDonald said, “In nature, nothing ever happens in a straight line”.  

Blue-green algae (cyanobacteria) is flourishing less often in Powers Lake now, because the Total Nitrogen to Total Phosphorus ratio (TN:TP) was increasing and moving closer to the threshold of a nutrient balanced lake with a ratio ranging from 10:1≤TN:TP≤ 30:1 [i]

Another indicator of water quality improvement was decreased total phosphorus levels and increased ratio of dissolved phosphorus to total phosphorus. Total phosphorus is the sum of particulate phosphorus and dissolved phosphorus which includes both organic and inorganic forms. Particulate (organic) phosphorus enters Powers Lake via attachment to soil particles through erosion, waste and decay of plants and aquatic life. Particulate phosphorus is converted to dissolved phosphorus (inorganic) phosphorus through natural chemical processes.

Conservation and Dredging Improve Water Quality

Total phosphorus levels are decreasing. Significant declines in total phosphorus levels indicate the combination of conservation activities and dredging are effective actions toward continued water quality improvement. Prior to the initial project in 2001, dissolved phosphorus comprised 45.9% of total phosphorus. During the conservation implementation phase in 2006 and 2007, dissolved phosphorus comprised 50.3% of total phosphorus. During the dredging phase of the project from 2015 to 2019, dissolved phosphorus comprised 72.6% of total phosphorus. The significant change in composition of dissolved phosphorus to total phosphorus from 50.3% during the conservation implementation phase to 72.6% during the dredging phase indicates removing in-lake nutrient sources via dredging is highly effective.

Dredging Improves Water Quality

Before the dredging began, it was anticipated that dredging would cause a temporary release of nutrients into the water. It was expected that the overall water quality where the dredge was active would be worse than the standard lake water sampling.

On the contrary, Powers Lake’s data confirms that dredging does not cause a release of nutrients into the water column. In fact, the nutrient concentrations, while mirroring the lake samples in terms of peaks and valleys, were consistently lower. The data confirms that dredging is more efficient at nutrient removal than anticipated.

Community Teamwork

For 22 years, the community harnessed the talents and contributions of many individuals and organizations worked together toward the common goal of improving water quality. This project has been assisted by farmers, ranchers, the City of Powers Lake, Mountrail Soil Conservation District(SCD), Burke SCD, NRCS in Mountrail and Burke Counties, US Fish and Wildlife Service, Burke County Extension Service, North Dakota Natural Resource Trust, Upper Dakota RC&D, North Dakota Game and Fish, Ducks Unlimited, and the many volunteers.  

Reclaiming Powers Lake

Powers Lake for Water quality is improving and people are coming to Powers Lake for camping, fishing, picnicking, hiking, bird watching, swimming, boating and gathering. Powers Lake serves as a recreational area for the city of Powers Lake and Mountrail and Burke Counties.

Since 2016, Powers Lake Watershed Committee runs a fishing derby for kids. It is a fun activity where families gather and people to enjoy fishing for northern pike. An average of 100 kids participate each year, which is impressive for a community with a population of four hundred. The fishing has improved! Ask the ten-year-old boy who caught the 13-pound northern pike at the 2019 fishing derby.

Reclaiming the high recreational value and natural resource at Powers Lake is happening. Better water quality means a higher recreational value at Powers Lake. The lake is regaining its reputation as one of North Dakota’s finest lakes for recreation and fishing and gathering. The lake serves as a classroom for Powers Lake Public School, a bird and fish habitat, and an aesthetic draw to the community. As a result of the talents, contributions and collaborations of many individuals water quality has progressively improved and the community is recapturing recreational value at Powers Lake, while the community and state of North Dakota reap the benefits. A lake is a reflection on the community that lives within its watershed.  

Personal interview and notes of Kenny MacDonald, Powers Lake Watershed Coordinator, Powers Lake, North Dakota

[i] Lake and Reservoir Management, Practical Applications : Proceedings of the Fourth Annual Conference and International Symposium, October 16-19, 1984, McAfee, New Jersey – North American Lake Management Society. Conference, https://play.google.com/books/reader?id=7VhGAQAAMAAJ&hl=en&pg=GBS.PA4

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