Many of the streams that flow through our cities are less than attractive due to years and years of neglect. They may flow brown with soil particles, have an oily sheen on the surface, and be practically devoid of aquatic life forms that we regard as desirable. Fish species that may be present in cleaner stretches of the stream are not to be found, nor are the insect larvae that they prey on.
The good news is that the very same stretches that appear hopelessly lost or dead can be brought back to life, and become a plus for a community. Stretches of stream ecosystems respond readily to changes in flow, shape, structure, and water quality by corresponding changes in the plant and animal communities of the stream. If conditions become unfavorable to them, they will simply die out or leave the area (if they are mobile) in search of more favorable haunts. Once conditions have sufficiently improved, the various species of plants and animals will quickly re-colonize the formerly impaired stretches.
How do favorable changes happen? How does a stretch of stream that has been neglected for years, perhaps decades, become a positive force rather than a negative one for a city? Early on, it is important to recognize that it is the entire watershed upstream of the city that contributes to the water quality of the stretch of stream within the city, and that all stakeholders in the watershed (or at least the vast majority) need to be involved and committed to the idea of stream improvement. Consensus building may be the most challenging of all aspects in a stream improvement project, as it will likely involve several jurisdictions and agencies with different budgets and timetables, as well as private landowners.
Assuming that a green light for stream improvement has been turned on, various action steps may be taken. Upstream, these may include land use change recommendations to reduce soil erosion, and the creation of streambank buffer strips of vegetation (small plants, shrubs and trees) to prevent eroding soil and fertilizer from flowing into the stream. The latter is also good within the city. Within the city limits, efforts to reduce direct stormwater runoff into the stream are important. Residents and businesses can be encouraged to incorporate rain gardens in low-lying areas on their properties, which greatly reduce the rapid runoff of rain water. The use of pervious pavement, rather than the traditional impervious forms, allows runoff water to percolate downward into the underlying soil, thereby reducing the volume of surface runoff from driveways, parking lots, streets, and airports. Specific steps within the stream itself might include creating a course of alternating pools and riffles, replacing bends if the stream has been channelized, placing rock riprap along streambanks in critical locations to reduce bank erosion, and adding structure (e.g., rocks of various sizes, logs, and bank hides) for fish habitat.
Following the action steps, it is important to assess the outcome, and to inform the stakeholders about the progress of the project. Perhaps some changes will need to be made to achieve the overall goals. However, it is likely that positive changes will be evident in very short order. Hopefully, the eventual outcome will be one where fish species that are native to the area and to the particular stream will once again be present, along with native plant life, aquatic insects, and other aquatic animals. This should also help to ensure the safety of the water for human contact. If this outcome is achieved, residents of the city and visitors alike should be favorably impressed with the beauty and condition of this rehabilitated resource.
Many cities in the Midwest have already undertaken projects to improve the appearance and water quality of streams that flow through their city limits. Others may have projects in the planning stage. We are interested in hearing about your completed and proposed projects.