Long Prairie River Watershed

Minnesota's Major Watershed Projects

The Long Prairie River Watershed (07010108) lies within the west-central portion of Minnesota, originating from Lake Carlos in east-central Douglas County. The Long Prairie River flows approximately 92 miles through Todd and Morrison Counties where it enters the Crow Wing River approximately one mile south-east of Motley. The watershed covers approximately 565,078 acres (883 square miles) and includes 65 lakes greater than 10 acres and 26 named stream assessment units (AUIDs).

The Long Prairie River provides habitat for aquatic life, riparian corridors for wildlife, and recreational opportunities such as fishing, swimming and canoeing. Today, roughly 54% of the watersheds landscape is utilized for cropland and/or pasture, 24% is forested, 7.5% is open water, and 6% is developed land that is used for housing, business and industrial complexes, county roads and city streets.

Monitoring and assessment

In 2011, the Minnesota Pollution Control Agency (MPCA) initiated an intensive watershed monitoring effort of the Long Prairie River Watershed’s surface waters. Thirty-seven stream sites were sampled for biology at the outlets of variable sized subwatersheds within the Long Prairie River Watershed. These locations included the mainstem Long Prairie River, outlets of major tributaries, and the headwaters of smaller streams. As part of this effort, MPCA staff joined with the Morrison, Douglas, and Todd County Soil and Water Conservation Districts (SWCD) as well as the Otter Tail County Coalition of Lake Associations (COLA) to complete stream and lake water chemistry sampling. In 2013, a holistic approach was taken to assess all of the watershed’s surface waterbodies for support or non-support of aquatic life, recreation, and fish consumption, where sufficient data was available. Twenty stream stream segments (e.g. AUIDs) and sixty lakes were attempted to be assessed in this effort. (Not all lake and stream AUIDs were able to be assessed due to insufficient data, modified channel condition or their status as limited resources waters).

Throughout the watershed, eight streams fully support aquatic life and four fully support aquatic recreation. Twelve streams do not support aquatic life and three do not support aquatic recreation. Aquatic recreation impairments are due to high bacteria levels. Three AUIDs will be proposed for delisting of their current impairment status: Long Prairie River (AUID 07010108-501) for Dissolved Oxygen, Long Prairie River (AUID - 504) for F-IBI, and Eagle Creek (AUID - 507) for F-IBI and M-IBI. Of the 65 lakes greater than 10 acres, 50 lakes support and 10 do not support aquatic recreation, while three do not support aquatic life due to high chloride concentrations.
Six AUIDs were not assessed for aquatic biology because the reach was over 50% channelized. Channelized reaches are currently not being assessed until new biological standards are developed. However a more general characterization of biological quality at channelized streams indicated that their condition ranged from poor to good for both fish and macroinvertebrates.

The primary resource concerns in the watershed are low dissolved oxygen concentrations on the Long Prairie River, as well as wind and water soil erosion and surface and ground water management/quality throughout the watershed. Changes in landuse patterns including increased development, wetland removal, and agriculture have all likely contributed to sediment and pollutant loadings to surface waters, thus reducing populations of sensitive aquatic species.

PDF icon Long Prairie River Watershed Monitoring and Assessment Report (wq-ws3-07010108b)

Strategy development projects

The MPCA created the strategy map to the right using HUC-12 subwatersheds – drainage areas within the larger HUC-8 Long Prairie River watershed – to help identify priority areas for targeting actions to improve water quality. Multiple sources of data, maps and analysis tools including HSPF, were combined to create this map.

  • Red – Water quality is poor but improvement is feasible, or water quality is exceptional and there are water qual­ity concerns to address with protection projects
  • Yellow – Medium priority for restoration or protection efforts (water is Impaired)
  • Green – Water quality is poor and improvement is not feasible, or water quality is exceptional and there are no major water quality concerns to address with protection projects

Local and other partners can use the priority-ranking map to help prioritize watershed and stream management ef­forts at the local level. Other maps of individual pollutants, such as phosphorus and nitrogen, can be found in the full report.

The restoration and protection strategies listed in the Watershed Restoration and Protection Strategy (WRAPS) report will be the basis for developing local implemen­tation plans to restore and protect water resources. The report lays out goals, milestones and responsible entities to address protection and restoration priorities in the Long Prairie River watershed. The targets are intended to provide guidance and “measuring sticks” to assess the watershed’s health and success of actions taken.

Protection and restoration strategies are dictated largely by the agricultural land use in the watershed.

  • Protection strategies for the watershed include riparian pasture management, shoreland development ordinances, Best Management Practice (BMP) adoption, nutrient management and stormwater management. Due to issues with channelization in the watershed, stream restoration projects are also an important strategy for both protection and restoration.
  • Restoration strategies involve cropland nutrient reductions through agricultural BMPs, feedlot runoff reductions, riparian pasture management, shoreland protection through natural plantings, buffers and shoreland stabilization projects.

PDF icon Long Prairie River Watershed WRAPS (wq-ws4-19a)

Implementation activities

In addition to the Total Maximum Daily Load (TMDL) study done in 2005 for low Dissolved Oxygen levels in the Long Prairie River (Long Prairie River Watershed - Low Dissolved Oxygen: TMDL project), another TMDL was done for bacteria and nutrients as part of the WRAPS process. This TMDL study addresses seven lakes and three streams within the Long Prairie River Watershed (HUC-07010108) that are on the 2014 303(d) list of impaired waters for aquatic recreation use impairments due to eutrophication (phosphorus) and E. coli (bacteria). Another TMDL project (Lake Winona TMDL) is currently in progress that addresses the nutrient impairment in Lake Winona.

Phosphorus in lakes often originates on land. Phosphorus from sources such as phosphorus-containing fertilizer, manure, and the decay of organic matter can adsorb to soil particles. Wind and water action erode the soil, detaching particles and conveying them in stormwater runoff to nearby waterbodies where the phosphorus becomes available for algal growth. Organic material such as leaves and grass clippings can leach dissolved phosphorus into standing water and runoff or be conveyed directly to waterbodies where biological action breaks down the organic matter and releases phosphorus.

The TMDL finds that reductions of 21%-63% are needed to meet water quality standards again in the seven lakes studied. The main strategy identified in the Long Prairie River WRAPS to improve water quality in Crooked, Echo, Jessie and Latimer Lake is to reduce watershed runoff before entering lakes and streams. The strategies that have been identified to mitigate watershed runoff include improving upland and field surface runoff controls, reducing bank/bluff/ravine erosion, increasing vegetative cover and root durations by planting crops and vegetation adjacent to riparian areas, and preventing feedlot runoff by conducting feedlot inspections and ensuring compliance. Reducing the internal load is the main strategy for Fish and Nelson Lake. Reducing the load coming from Fish Lake is the main strategy to improve water quality in Twin Lake.

Humans, pets, livestock, and wildlife all contribute bacteria to the environment. These bacteria, after appearing in animal waste, are dispersed throughout the environment by an array of natural and man-made mechanisms. Needed bacteria reductions from agricultural runoff range from 14% to 92%, depending on the flow and specific stream.   Specific practices such as improved field manure (nutrient) management plans, adhering to or increasing application setbacks from riparian areas, improving feedlot runoff control and rotational grazing including livestock exclusion.

PDF icon Long Prairie River Watershed TMDL Study (wq-iw8-49e)


    Information contact

    Anna Bosch
    Watershed Project Manager
    MPCA Brainerd Regional Office
    7678 College Rd, Suite 105, Baxter, MN 56425