One doesn’t need to dig very deep to see how important the Duluth stormwater system is. The flood of 2012 is a perfect example of what happens when a stormwater system fails. The floods resulted in over $100 million in damages and have had a lasting impact on the entire city. Even without such a severe flood event, homes, businesses, and roads in Duluth can be damaged by water infiltration during any large weather event. The climate of Duluth has already changed, and further changes are predicted, including more rainfall overall, and stronger and more frequent storms. As storms become larger and more common, having a system that is able to handle more runoff is necessary for overall community wellbeing.
Having an effective stormwater system is vital to our community, but it requires ongoing maintenance and investment. Starting in 1880 the stormwater system was built to handle snowmelt, rainfall, and runoff; it was designed to carry damaging and potentially dangerous water away from homes, businesses, and roads. Ideally this system prevents flooding and protects our streets and other infrastructure.
Our Current Stormwater Systesm is made up of:
- 411 miles of pipe
- 10,931 catch basins
- 5,044 manholes
- Over 100 miles of ditches
Being over 100 years old, the Duluth stormwater system needs repairs, and this work can be expensive. Preventative maintenance is key, however if a part of the system fails, the repairs must be dealt with right away. Maintenance and planning for the system are managed by a busy team of skilled workers and engineers. These folks are led by City of Duluth Senior Engineer, Tom Johnson. The department has identified over 4 million dollars needed for annual maintenance of the system, but they operate on much less funding.
The oldest part of this system is a section of 8.4 miles of pipe that was installed in 1880. These pipes typically have a lifespan of 100 years, and there are approximately 36 miles that have reached that age. The cost to replace one mile of this old pipe is around $907,000/mi, assuming that part of the system hasn’t failed and needs emergency replacement. The cost and time needed to maintain the system will impact residents and businesses, but the impact won’t be nearly as severe as another flooding event.
Stormwater pollution is a threat to water quality, and pollutants can be carried off streets, driveways, yards, and buildings with runoff. It all ends up in local streams, and eventually Lake Superior. Stormwater is not treated at a sewage treatment plant, so we rely on preventative actions and proper maintenance. We also try controlling the sources of stormwater pollution: road salt, litter, pet waste, and yard chemicals are a few of many pollutants that find their way into the stormwater system. Sediment traps, and remote monitoring systems help maintain water quality and collect data on these pollutants. Best Management Practices (BMPs) like rain gardens and infiltration basins put in place by the city and local businesses also help prevent pollutants from reaching Lake Superior. Residents can also be part of protecting water quality, including: proper waste disposal, picking up after our pets, and minimizing lawn chemical use.
There is a lot more information available about our stormwater from the Regional Stormwater Protection Team (RSPT). Learn more at https://www.lakesuperiorstreams.org. The City of Duluth breaks down the utility cost and how businesses obtain Best Management Practice.