North Raccoon
WMC Watershed

North Raccoon WMC
Storm Lake, IA
2,470 square miles

One watershed, one community charting its own destiny through shared responsibility and common goals. Working together for reduced flooding, improved water quality and soil health, enhanced education and strengthened community.

This planning effort was pursued in response to recent destructive flood events across the state. According to the Iowa Flood Center, Iowa has seen 18 billion dollars in flood damage over the last 30 years (Arenas Amado et al. 2018). The floods of 2008 in Iowa resulted in the sixth-largest FEMA disaster declaration ever (to date), based on estimated public financial assistance (City of Cedar Rapids 2020). Such flooding events are becoming more frequent in the state.

Low-income, marginalized and socially vulnerable populations are only as resilient as the social resources available, yet a community’s flood resilience is only as strong as its most vulnerable populations. Flooding impacts both the well-being of communities in the watershed as well as the economic capacity of vulnerable communities to protect their residents.

High nitrate levels and pathogen levels in surface and groundwater supplies pose potential risks to local drinking water supplies. Impacts on Des Moines Water Works operations have been well publicized. However, two other communities, Dawson and Lake View, have had impacts due to high nitrate levels. Nearly 80% of the wells throughout the watershed have been identified as highly susceptible. In addition, bacteria contamination has been noted in numerous private wells. In total, over 300 private wells across the watershed have found elevated levels of nitrate or bacteria.

In the North Raccoon River Watershed:

There are 12 waterbodies where primary-contact recreational uses are impaired due to elevated bacteria levels.

There are 10 waterbodies where conditions to support aquatic life are impaired due to a variety of factors: turbidity, algal growth and biological.

These conditions can prevent public use of existing resources for recreation. They can also impact the desire to expand the network of other recreational opportunities (such as the Central Iowa Water Trails network). In addition to recreational impacts caused by sediment noted previously, high levels of sediment runoff can reduce storage volumes in lakes, wetlands, ponds and other stormwater storage practices. This can lead to costly dredging or soil-removal operations. High levels of sediment can also cover rock and cobble areas which may be used as habitats for fish and invertebrates. Deposition in channels along inside bends can also accelerate stream migration, an erosive process that itself generates sediment. Deposition can accelerate the movement of outer bends in an outward (and generally downstream) direction.

High nutrient levels can lead to the growth of algae and other organisms that can reduce oxygen levels in water bodies. When populations of these organisms die off, the process of decay consumes oxygen. If levels fall too low, aquatic life in those areas can be fatally impacted. Some species may be able to swim to areas with better oxygen levels. Slow-moving aquatic life may not be able to move fast enough to survive (NOAA 2020). These conditions can sometimes be present in Iowa streams and lakes. However, a large hypoxic “dead zone” has formed in the Gulf of Mexico, where dissolved oxygen levels are less than 2 mg/L. This area is now the second-largest “dead zone” in the world. This has led to a national effort to reduce the size of the dead zone to 5,000 square kilometers (1,930 square miles). The size of the dead zone varies from year to year due to weather conditions. Over the last five years of measurements (2014–2019) the zone has measured between 7,000 and 22,700 square kilometers (2,700 to 8,800 square miles). Those national efforts led to the formation of Iowa’s NRS to address nitrogen and phosphorus pollution (U.S. EPA 2015).

Watershed Area Assessed
2,470  SQM
Subwatersheds Encompassed
75  HUC-12
From Iowa Involved
13  Counties

The NRRWMC (North Raccoon River Watershed Management Coalition) decided to make flooding and water quality the primary issues for this plan to address. Strategies to address these goals include quantifying practices and estimating costs to achieve a set benchmark. After considerable discussion, the NRRWMC decided to adopt the nitrate reduction determined by the Raccoon River TMDL (48.1% reduction from point and non-point sources) and the phosphorus-reduction target established in the Iowa NRS for non-point source pollution (45% reduction total, 29% assumed for non-point sources).

The NRRWMC chose to consider pathogens—represented by Escherichia coli (E. coli) bacteria—and sediments as secondary issues for this plan to address. However, no numeric reduction objectives would be established for these issues, due in part to the complex nature of fully implementing practices and monitoring performance to address these pollutants.

The NRRWMC will need to grow in unity and find financial resources to implement this plan. They will need to be organized as a group and seek to expand the list of active partners who will be acting and advocating for additional outside support.