Stormwater Utility Information
The City of Columbus has a history of flooding and other stormwater concerns. While nothing we do can flood-proof the City, there are projects and improvements that could improve conditions and mitigate some effects during high water events. Additionally, the stormwater infrastructure found throughout the City needs routine service and maintenance to ensure proper operation when we need it most.
CURRENT STORMWATER SYSTEM
Presently, the City of Columbus is comprised of approximately 4.5 square miles with parts of 21 different stormwater drainage basins located within city limits which are identified on this drainage basins map. These basins contain various private and public stormwater facilities (dry and / or wet ponds, bioretention and infiltration) and other best management features that help with reduction of stormwater and improve water quality for the city.
The City has 7 major drainage methods within its limits. They account for 7.81 miles of drainage channels and creeks. These all have pipes / culverts associated with their operation with sediment and vegetation removal required to ensure they are operating efficiently.
Inventory for storm sewer includes 27 miles of streets with 986 storm structures (manholes and inlets) and 2,111 storm sewer pipes throughout the city to convey water.
Flooding events that have overtopped streets within the city have been documented in:
2007, 2008, 2010, 2018, 2019 (spring and fall), 2020 with locations and elevations as shown on this downloadable flood elevations map.
2008 flooding in a residential area
Much of the old storm system was installed decades ago and is comprised of clay pipe that is typically undersized with a lack of storm inlets to capture water. These pipes are replaced, upsized, and inlets added to help carry water away from properties more efficiently when a street reconstruction is completed.
12-inch pipe 90% filled in with sediment in Kestrel Ridge development taken 12/1/2021
The City owns and maintains 15 stormwater facilities in the City of Columbus encompassing approximately 23 acres. By comparison, there are about 29 privately owned facilities in the city. All this infrastructure must be maintained, repaired, and cleaned periodically to ensure it functions as intended. Ditches, structures, and pipes can become clogged with sediment and no longer operate as designed.
They are a mix of residential and commercial/industrial facilities located throughout the different basins. Primarily, stormwater facilities are located in newer areas of development within the city that were subject to regulations that were not in place historically. Much of the older residential parts of the city and downtown areas do not have stormwater facilities present.
All stormwater facilities need routine maintenance to ensure they are kept in good working order. The pipes, ditches, channels, and structures need to be upgraded and repaired when they reach the end of their useful life and/or fail. The typical maintenance for stormwater facilities includes mowing, removal of debris, dredging, repair to outlet structures, and pipes. The typical maintenance of structures and pipes in the street include cleaning out sediment that accumulates and repair of collapsed and damaged pipes.
The City has budgeted various amounts for annual maintenance over the years between $0 and $25,000 for the entire city.
Total: $1,030,393 borrowed in the past 10 years (not including interest on debt service, channel maintenance, pond maintenance, culvert removal or replacement).
FUTURE OF STORMWATER UTILITY
Currently the City of Columbus continues to have needs and expenses associated with stormwater management. The Utility will help shift some of the annual ongoing costs off the current budget, borrowing and debt service while allowing the City to focus on being proactive instead of reactive.
Columbus currently doesn’t require an MS4 permit by the Wisconsin DNR, but all communities will be required to have the permit. To learn more about MS4 permits, go to: https://bit.ly/municipal_stormwater_overview
The estimate for the current stormwater utility at a fee of $5 per Equivalent Runoff Unit (ERU) per month would generate approximately between $200,000 and $250,000 annually for stormwater operation, maintenance, and future capital expenses. The exact amount will vary on the year, number of customers and any credits for that year. These funds would go toward the current maintenance of existing items such as:
- Mowing routine preventative maintenance of ponds; Annual estimated cost of $75,000.
- Storm sewer collection system maintenance (cleaning structures and pipes, repair of failed pipes or inlets); Annual estimated cost of $25,000.
- Capital street reconstruction storm costs; Annual estimate of $100,000.
These estimated costs are shown for the current level of engagement to meet what the City historically has done and would vary annually. There is need for additional maintenance and improvements that can be identified and added but, the City currently cannot fund.
The City’s goal would be to create a city-wide stormwater management plan to better understand the potential projects that would improve water quality and lower flooding risks. This plan would identify future projects, estimate costs and priorities, and provide direction for the stormwater utility into the future. Some examples of projects would be:
- New ponds to reduce flooding within and upstream of residential areas that don’t have facilities to reduce runoff.
- Potential pond expansion to increase capacity for runoff.
- Flood storage areas and projects to store flood waters and reduce impact to structures.
- MS4 projects to improve water quality within the city and river basins.
- Large capital cost upgrades and replacements throughout the city.
All the identified projects in this management plan would qualify for stormwater utility funds to implement. Cost likely would range from a few thousand dollar upwards of hundreds of thousands of dollars per project or more.
The City understands that the amount of money collected will not cover ALL of the needs, but the Stormwater Utility is being planned to balance those needs with the fiscal burden to the residents.