The Minnesota Pollution Control Agency has reached the midpoint of its first comprehensive look at water quality — and what is needed to protect and restore it — throughout the state. The agency and its partners have used a watershed approach to take an in-depth look at the lakes and streams in half of the state’s major watersheds.
How are our watersheds? Water quality is a reflection of what happens on the surrounding land. So far, the MPCA's monitoring and assessment work highlights the following themes:
- In watersheds dominated by agricultural and urban land, half or less of the lakes fully support the standard for swimming because of phosphorus. Excess phosphorus is the main driver of harmful algae in lakes.
- Watersheds that are heavily farmed tend to have high levels of nitrogen, phosphorus and suspended solids in their waters. These pollutants hurt aquatic life and recreational opportunities.
- Bacteria levels in streams are also a problem. Watersheds where less than half the streams fully support swimming because of bacteria levels are generally in areas with a higher density of people and livestock — the developed and agricultural portions of the state.
- The vast majority of streams and lakes examined — 97% of 490 stream sections and 95% of 1,214 lakes studied — contain fish tainted by mercury.
- More lakes fully support the swimming standard in the more forested and wetland-rich areas of north-central and northern Minnesota. The same goes for streams in areas with lower populations and little animal agriculture.
- The general pattern is that water quality is exceptionally good in the northeast part of the state and declines moving toward the southwest.
Once we've monitored and assessed a watershed, our next step is to identify conditions stressing water quality, fish and aquatic life. The MPCA and partners have identified stressors in about one-third of Minnesota’s watersheds so far. These interrelated stressors include:
- Stream connections, such as culverts and tile drainage
- Hydrology, including stream flow and runoff
- Stream biology, such as fish and bugs
- Water chemistry, including oxygen levels, nutrient levels and temperature
- Stream channel assessment, mainly erosion
- Southern Minnesota has the highest numbers of stressors related to excess nutrients, excess sediment, lack of habitat, lack of connectivity, altered hydrology and impaired biological communities.
- In the northern-central and northwest regions, low dissolved oxygen was the most common stressor found.
- In the Twin Cities, excess sediment was a common stressor along with altered hydrology.
Fixable? Strategies to help our water
The third step in our watershed approach is to develop Watershed Restoration and Protection Strategies that the state, local partners, landowners, and citizens will implement. While each watershed is different, some general themes have emerged for the 10 watersheds that have completed this step:
- In watersheds where agriculture dominates the landscape, prominent strategies include stream buffers, nutrient and manure management, wetland restorations and other forms of water storage and stream channel stabilization.
- For more urbanized areas, strategies focus on stormwater runoff controls ranging from site planning, to rain gardens, to the construction of stormwater ponds and wetlands.
- Not all strategies relate to traditional water pollutants. Throughout Minnesota, common strategies include improving habitat and reducing barriers (connectivity) for fish and other aquatic life.
- Some strategies call for stronger and more targeted application of state and local laws on feedlots, shoreland and septic systems. The MPCA leads permitting work for stormwater controls and wastewater discharges.
Bottom line — we’re in it for the long haul
A long-term commitment is needed to restore and protect Minnesota’s waters. Implementing the strategies identified so far will take 20, 30 years or more with interim milestones to measure and motivate progress.
It took decades to pollute lakes and streams, and it will take many years to restore impaired waters while working to protect healthy waters as new threats emerge.
Find out more about your watershed on the MPCA's Minnesota watersheds webpages.