Stormwater

Rochester has had historic floods in 1855, 1866, 1882, 1908, and 1978.  The 1978 flood was the worst Rochester had experienced. In response, the City of Rochester, Olmsted County, and the Olmsted Soil and Water Conservation District, with assistance from the Corps of Engineers and the Natural Resource Conservation Service (NRCS), constructed a flood protection project from 1984 to 1995.

The historic 1978 flood was used as a model during the design process so that the Flood Control Project could handle any flood event previously experienced in the community. The Flood Control Project uses a multi-faceted approach that combines water storage in upstream reservoirs, stream bank stabilization, construction of a wider, deeper channel, and levees. This has reduced flood risk in Rochester to 0.52% per year and reduced downstream flooding impacts.

Please contact the City of Rochester with questions about the Flood Control Project by calling Public Works at 507-328-2411 or by sending an email.

Current River Levels

The Minnesota Department of Natural Resources (DNR) and the Minnesota Pollution Control Agency (MPCA) provide access to near-real-time and historical streamflow and water-quality data across Minnesota via the Cooperative Stream Gaging Website.

Gaging Sites in Rochester

• Bear Creek at Rochester and Highway 14
• Cascade Creek at 7th Street NW
• Cascade Creek at 45th Avenue SW
• Silver Creek at Silver Creek Drive NE 
• Silver Creek near Silver Creek Road NE
• South Fork Zumbro River at Highway 14
• South Fork Zumbro River near County Road 104

Rochester's Watershed

The City of Rochester is part of the Zumbro River watershed, which drains to the Mississippi River and ultimately the Gulf of Mexico. The watershed covers more than 900,000 acres across six counties.

Within Rochester, nine smaller watersheds carry water through the community:
Bear Creek, Cascade Creek, Hadley Valley, Kings Run, Mayo Run, River Run, Silver Creek, Willow Creek, and the Zumbro River.

When rain or snowmelt runs off the landscape, it can carry pollutants into local waterways. While pollution from a single property may be small, the combined impact across the watershed can affect water quality locally and downstream.

Rivers, Streams & Wetlands

Surface water covers about 3% of Rochester’s land area. Our rivers, streams, and wetlands:

• Provide habitat for wildlife
• Offer recreation opportunities
• Receive stormwater runoff from across the watershed

Rochester developed along the South Fork of the Zumbro River floodplain, and these waterways continue to play an important role in the community’s quality of life.

Water Quality & Impaired Waters

Clear water is not always clean. Pollutants such as bacteria, nutrients, sediment, and mercury can affect water quality even when they are not visible.

The Minnesota Pollution Control Agency (MPCA) monitors water quality and identifies “impaired waters.” A water body is considered impaired if it does not meet standards for uses such as drinking water, fishing, or swimming.

About 40% of Minnesota’s lakes and streams are impaired, and Rochester’s major waterways are included on the state’s Impaired Waters List. Protecting and improving water quality requires action across the entire watershed.

Wetlands in Rochester

A wetland is an area where soils are saturated, and water is at or near the surface, supporting plants adapted to wet conditions.

Minnesota has eight wetland types. Six occur in Rochester:

• Shallow marsh
• Shallow open water
• Shrub swamp
• Wooded swamp
• Seasonal basin
• Wet Meadow

Rochester has about 800 acres of wetlands, covering roughly 2–3% of the city (seasonal conditions may affect estimates).

Statewide, about 10.62 million acres of wetlands remain, roughly half of Minnesota’s original wetlands. Minnesota still ranks second only to Florida among the contiguous states for wetland diversity.

Why Wetlands Matter

Wetlands provide important benefits:

• Reduce flooding by storing rain and snowmelt
• Prevent erosion along lakes and streams
• Provide wildlife habitat (43% of threatened or endangered species rely on wetlands)
• Recharge groundwater
• Improve water quality by filtering sediment and pollutants
• Support recreation like birding, fishing, and canoeing

Rare Wetlands: Calcareous Fens

Calcareous fens are rare wetlands fed by mineral-rich groundwater and known for high biodiversity.

Key facts:

• Only 0.03% of Minnesota wetlands are fens
• Fens cover about 4,000 acres statewide
• 10 of Minnesota’s ~200 fens are in Olmsted County
• 4 fens are located within the Rochester city limits