Rochester has had historic floods in 1855, 1866, 1882, 1908, and 1978.  The last flood in 1978 was the worst Rochester had experienced. In response, the City of Rochester, Olmsted County, and the Olmsted Soil and Water Conservation District, with assistance of 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 reservoirs upstream, stream bank stabilization, construction of a wider and deeper channel, and levees. This has reduced flood risk in Rochester to 0.52% in any given year and has reduced the impacts of flooding downstream.

Please contact the City of Rochester with questions about the Flood Control Project by calling Public Works at 507-328-2400 or send an email.

Stay in the know!

If you plan to use the river for recreational use or live in a floodplain area please keep the following information handy.

City of Rochester Emergency Management Website

Current River Levels

The Minnesota Department of Resources (DNR) and the Minnesota Pollution Control Agency (MPCA) provide access to near real-time and historical stream flow and water quality data across the state of 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

Evaporation. Condensation. Precipitation. Infiltration. Runoff. 

The water cycle describes how water changes forms and moves above and below the surface of the Earth. The impacts of development and urbanization have had great impacts on water. The Urban Water Cycle takes into consideration stormwater moving across hard landscapes where it can't soak into the ground, groundwater being pumped to the surface for use in homes and businesses, and wastewater traveling to water treatment plants.

source: nasa.gov

source: neorsd.org

Parts of the Urban Water Cycle

Stormwater

Rochester receives an average of 31 inches of rain and 44 inches of snow each year.

Rain and snow-melt that falls on buildings, streets, parking lots, and other impervious surfaces cannot soak into the ground. Instead, this stormwater will run off the landscape into area waterways.  Compared to natural settings, the amount of stormwater that will runoff in an urban area is greater and the speed the water travels is faster.  The increased amount of fast-moving water flowing across the land surface causes erosion and collects pollutants, which are then transported to receiving waters, such as, streams, rivers, ponds, and lakes.

The Federal Clean Water Act requires the City of Rochester to manage stormwater runoff within the city limits by law. 

Learn more about these requirements and pollution prevention measures by exploring this website!

Wastewater

Wastewater is used water from residences, commercial buildings, and industrial facilities. It is also sometimes called sanitary sewage.

According to the U.S. Environmental Protection Agency (EPA), the average American produces 100 gallons of wastewater each day. The goal of the City of Rochester is to return wastewater to the water cycle at the Zumbro River with as little environmental impact as possible.

After water goes down the drain or the toilet is flushed, where does the water go? Wastewater is carried from homes, and commercial and industrial businesses, through a network of buried pipes, called a sanitary sewer collection system, to the Water Reclamation Plant located in NW Rochester. Once there, the water undergoes an advanced and complex process that reduces contaminants to levels required by the Water Reclamation Plant’s operating permit before being returned to the environment via the Zumbro River.

Follow this link to learn more about the City of Rochester's Water Reclamation Plant.

Did you know.... storm sewers and sanitary sewers are kept separate!  Storm sewers carry stormwater directly to surface waters.  Sanitary sewers carry wastewater to the water reclamation plant for treatment before being discharged into the river.

Groundwater

In Rochester, the City gets its water from deep under the ground. The entire process of taking the water from below ground and bringing it into the homes and businesses in Rochester is managed by Rochester Public Utilities (RPU).

Rochester’s water supply is extracted from bedrock aquifers which are large rock formations that hold water in small fractures within the rock layers or in the pore spaces between the particles that form the rock. Fractured limestone and porous sandstone are the aquifer-forming rocks in the Rochester area. To be a dependable source of water, aquifers must be both porous, (meaning there are spaces for the water to be in) and permeable, (the water can move easily through the rock). Most of Rochester’s water comes from the Jordan Aquifer which is composed of sandstone. Rochester sometimes also uses other aquifers such as the St Peter, Prairie du Chien limestone, the Ironton-Galesville sandstone, and the Mt. Simon sandstone.

Even though the quality of the water supply is good today, the local geology presents risks for contamination. Where the underlying soils and bedrock are both permeable, the wells are vulnerable to pollution. The thicker and the less permeable the soil layer, the more the filtering capacity, reducing the risk for groundwater pollution. Thus, our actions on the land can have a direct impact on the quality of our groundwater supply.

Follow this link to learn more about Rochester's groundwater on the Rochester Public Utilities website.

A wetland is described as an area with mostly wet soils, water either above or just beneath the surface of the ground, and vegetation that is adapted to grow in wet conditions. 

Wetlands are part of the foundation of our nation's water resources and are vital to the health of waterways and communities that surround them. There are eight different types of wetlands in the state of Minnesota. In Rochester, you can find six of these wetland types: shallow marshes, shallow open water, shrub swamps, wooded swamps, seasonal basins, and wet meadows. (The two you will not find in Rochester are bogs and deep marshes.) There are approximately 800 acres* of wetlands within Rochester city-limits, which equates to 2-3% of the ground cover. *This number is dependent upon the season.

The Minnesota Department of Natural Resources (DNR) estimates there are about 10.62 million acres of wetlands remaining in Minnesota. Unfortunately this number is about half of what was originally found in the state. Even with the drastic decrease in the number of wetlands, the state of Minnesota is second only to Florida (among the contiguous states) in the diversity and extent of wetlands.

The many jobs of a wetland

Erosion Control: Wetlands reduce erosion along lakes and stream banks by reducing the forces associated with moving water.

Flood Control: Wetlands slow runoff water down and store water from intense rain storms and times of snow melt. This then helps to minimize the frequency in which streams and rivers reach catastrophic flood levels.

Habitat: Wildlife of all shapes and sizes depend on wetlands for food sources, resting spots, protection from predators, and spawning or rearing their young. 43% of threatened or endangered species, including plants and animals, live in or depend on wetlands.

Groundwater Support: By detaining surface waters that would otherwise quickly flow away, water in wetlands can instead percolate into the ground. Some wetlands receive groundwater during dry periods which helps reduce the impact of short term droughts.

Natural Filter: When water is trapped and held in a wetland, nutrients and pollutants become stored in the soils which results in cleaner water flowing into the body of water beyond or below the wetland. Vegetation, like cattails, can absorb some of the pollutants that remain in the soil. Wetlands also moderate water flows, providing time for sediments to settle out before water is released, resulting in cleaner waters.

Recreation: Wetlands provide opportunities for outdoor recreational pursuits including canoeing, fishing, hunting, birding and exploration.

Income: Wetlands provide economic commodities such as cranberries, wild rice, and fish. Additionally, developments benefit from the spatial amenities wetlands can provide.

Rare Natural Community in Rochester!

Calcareous fens are one of the rarest natural communities in the United States. These unique wetlands, which are a type of wet meadow, are fed by mineral-rich groundwater and have little inflow of surface runoff. Fens are highly diverse with over 100 different plant species, some of which are rare, threatened or endangered.

Fen Fun Facts:

• Fens comprise only 0.03% of all wetlands in Minnesota, making them a very rare type of wetland.
• Of Minnesota's 53,775,155 total acres, fens cover only 4,000 acres - this is equal to 0.007%!
• Biodiversity is high in fens. Almost 20% of the plant species found throughout Olmsted County are found in our fens.
• Fens are home to rare, threatened, and endangered amphibians, reptiles, snails, and butterflies.
• Olmsted County has the third highest number of inventoried fens in the state. 10 of the state's 200 fens are found here.
• There are 4 known fens located with the city limits of Rochester.

Learn more about fens in the handouts below:

• Calcareous Fens: Are you a fen-friendly neighbor?
• Fen-Friendly Care Practices for Stonehedge Residents
• Fen-Friendly Care Practices for Barony Woods Residents

The City of Rochester lies within the Zumbro River watershed, which in turn drains to the Mississippi River, which drains to the Gulf of Mexico. The Zumbro River watershed is more than 900,000 acres in size and reaches parts of six counties. Within our watershed, there are nine smaller watersheds: Bear Creek, Cascade Creek, Hadley Valley, Kings Run, Mayo Run, River Run, Silver Creek, Willow Creek, and the Zumbro River.

Whenever water runs off the landscape it has the potential to pick up pollutants. While the pollutants coming off a single property may not be great, it is the cumulative effect of all pollutants in the watershed that impacts the receiving waters. The effects of stormwater pollution are seen on watersheds of any size, ranging from creeks in Rochester to the Gulf of Mexico's "Dead Zone."

Follow this link to learn more about the Zumbro River Watershed and other Watersheds in Minnesota on the Minnesota Pollution Control Agency's website.

Zumbro Watershed Restoration and Protection Strategies (WRAPS) Summary

Zumbro River One Watershed, One Plan

Surface water covers about 3% of the ground cover in Rochester. Our rivers, streams, and wetlands provide recreational opportunities for people and habitat for wildlife.  These surface waters are also the receiving waters in our watershed.

Rivers & Streams in Rochester

Rochester was built on a floodplain created by the South Fork of the Zumbro River and its tributaries. Our rivers and streams travel throughout the city and increase the quality of life in Rochester.  As our community grows, so must our commitment to protecting and improving the quality of our water resources. Keeping our water resources clean and usable is in everyone's interest.

Clear water doesn't necessarily mean it is clean. There are a wide variety of pollutants, both visible and invisible to the naked eye, that pollute our waterways. The Minnesota Pollution Control Agency (MPCA) is responsible for monitoring and assessing water quality, listing impaired waters, and determining the amount of pollutants a water body can handle (Total Maximum Daily Loads, TMDL).  The TMDL standards define how much of a pollutant (bacteria, nutrients, turbidity, mercury, etc.) can be in the water and still meet designated uses, such as drinking water, fishing, and swimming. A water body is “impaired” if it fails to meet one or more water quality standards

Monitoring suggests that about 40 percent of Minnesota's lakes and streams are impaired for conventional pollutants, a rate comparable to what other states are finding. All of Rochester's major waterways are considered "impaired." Impaired waters identified through the assessment process are placed on the Minnesota's Impaired Waters List.

Click here to view the Minnesota Pollution Control Agency Impaired Waters Viewer 

Visit our Clean Water Actions page to learn how to prevent pollution and care for our polluted water.