From the start of the Minneapolis Park and Recreation Board (Park Board) master-planning process for the future of Cedar Lake and Lake of the Isles (Cedar-Isles) and surrounding parkland, water quality surfaced as the primary concern of the Community Advisory Committee (CAC).
In response to concerns raised by Cedar-Isles CAC members that water quality was not being adequately addressed in early master-planning phases, several members formed a Water Quality Subgroup to address this critical subject as the basis of the master-planning process.
In April, Park Board commissioners authorized an additional $50,000 for more consulting capacity from EOR, a water resource-based engineering and environmental consulting firm subcontracted through TEN x TEN, the lead consultants on the Cedar-Isles project.
Multiple Challenges: Pollution and Climate Change
The challenge of protecting and improving water quality in Cedar Lake and Lake of the Isles is complicated by the reality that the Chain of Lakes is part of a large watershed (Minnehaha Creek Watershed District) that includes multiple communities and jurisdictions, including St. Louis Park and surrounding neighborhoods. Water from these neighborhoods eventually flows to Brownie Lake, Cedar Lake, Lake of the Isles, Bde Maka Ska and Lake Harriet, on the way to Minnehaha Creek and ultimately to the Mississippi River.
Cedar and Isles are essentially catchment basins that receive stormwater nutrient loads from upstream lakes and communities. As population, development and hardscape increase in upstream areas, the amount of runoff pollutants flowing to Cedar and Isles continues to increase.
According to the Environmental Protection Agency (EPA), nutrient pollution is one of America’s most widespread, costly, and challenging water quality problems, caused by excess nitrogen and phosphorus. Nutrient pollution has impacted many streams, rivers, lakes, and other water bodies for the past several decades, resulting in serious environmental and human health issues.
Two major pollutants, nitrogen and phosphorus, are nutrients that are natural parts of aquatic ecosystems and support the growth of algae and aquatic plants, which provide food and habitat for fish, shellfish and smaller organisms that live in water. When too much nitrogen and phosphorus enter the environment—usually from human activities—the air and water become polluted.
In the case of Cedar Lake and Lake of the Isles, major sources of nutrients include pet waste and phosphorus in fertilizer and leaf litter that enters the lakes as stormwater runoff.
Too much nitrogen and phosphorus in the water causes algae to grow faster than ecosystems can handle. Significant increases in algae harm water quality, food resources and habitats, and decrease the oxygen that fish and other aquatic life need to survive. Large algae growths, called algal blooms, can severely reduce, or eliminate oxygen in the water, leading to illnesses in fish and the death of large numbers of fish. Some algal blooms are harmful to humans and pets when they produce elevated toxins and bacterial growth that can make people sick if they come into contact with polluted water, consume tainted fish or shellfish, or drink contaminated water.
Climate change also poses challenges to water quality. The Minnesota Pollution Control Agency predicts that climate change will result in higher temperatures, more extreme storms with intense flooding, and changes in our ecosystems.
Based on historical trends, models project that the average temperature in the Twin Cities metro area will rise between 3 degrees and 5 degrees F through mid-century, with more high temperature days (days above 90° F). Summers will likely be hotter and drier, and winters will be warmer and snowier (or wetter). These changes will have profound effects on lake conditions, including vegetation, invasive species, and thermal energy layers that affect the life cycles of fish and other organisms.
Water Quality Goals
In April, EOR hosted three Cedar-Isles CAC Water Quality Subgroup meetings that explored qualitative aspirations, quantitative analysis, and goal-setting for the two lakes. EOR guided subcommittee members and the public through the complexities of water quality through a variety of scales and various pollutants of concern. Subgroup members were committed to establishing measurable goals that could address ways to reduce nutrient pollution and adapt to climate change (precipitation patterns, water temperatures, lake stratification, and ice cover/ open water dynamics).
Based on the discussion during subcommittee meeting #3, CAC members suggested renewing the rigorous goals established during the Clean Water Partnership (CWP), a project undertaken in the 1990s by the Minnehaha Creek Watershed District (MCWD) to improve the water quality in the Minneapolis Chain of Lakes. This award winning partnership included the cities of Minneapolis and St. Louis Park, the Minnehaha Creek Watershed District, the Minnesota Pollution Control Agency, Hennepin County, and the Minneapolis Park Board.
According to MCWD, the effort required six years of planning, many hours of meetings with citizens and stakeholders, careful coordination with local elected officials, and thoughtful design work. The result was the largest urban lake restoration program in the nation at that time.
As the Cedar-Isles consultants studied the current and historic water quality conditions and impacts, they concluded that the CWP’s approach to evaluating the lakes and formulating a plan with measurable goals resulted in positive changes in the lakes.
The CWP provided strong, technically solid work and impressive accomplishments that are now considered innovative for the 1990s. Postulating that some of the CWP work may be nearing the end of its life span, the Cedar-Isles consultants suggested it may be time to revisit some of those practices as a way to inform water quality goals and future management strategies for the Cedar-Isles master plan.
The goals and objectives proposed by the CAC’s Water Quality subcommittee fall into three categories:
- Lake-level goals that involve formalized plans for both lakes to manage in-lake nutrients and littoral (shoreline) zones, metrics and activities.
- Master Plan-level goals that address the key themes of managing runoff and other pollution (including chloride, trash, and sediment) and balancing recreational needs with the need for ecologically healthy lakes.
- High-level watershed goals that formalize collaboration among agencies, reinvigorate the Clean Water Partnership and renew efforts to meet CWP objectives.
The CAC’s water quality goals reflect the intention to prioritize environmental protection in the Cedar-Isles Master Plan and to use the plan as a case study to implement Park Board master plans through the development of specific measurable outcomes to meet goals and objectives.
Given the multiple agencies with jurisdiction over these lakes, including the city of Minneapolis, these goals (once approved and incorporated into the master plan), will need to be adopted in the City’s state-mandated Minneapolis Stormwater Management Plan to have any real meaning and lasting effects.
