Q: What was the purpose of the Minnesota River Flood Mitigation study?
The study’s purpose was to investigate feasible transportation solutions to the seasonal flooding in the Minnesota River Valley in the southwest metro. It focused on the bridges and approach roadways over the Minnesota River for Hwy 41, Hwy 101 and Hwy 169. The study helped determine which capital improvements would be necessary to minimize roadway closures and/or add capacity during seasonal flooding.
Q: Why did we need a study?
spring flooding frequently closes the Hwy 101 and Hwy 41 Minnesota River crossings, which has a detrimental effect on traffic in the region. Although the U.S. Hwy 169 river crossing is relatively new, it does not have sufficient capacity to efficiently handle the volume of traffic detoured during closures at the Hwy 41 and Hwy 101 river crossings. It will be decades before the Hwy 41 Minnesota River crossing is replaced given current funding levels. The study was needed to identify and analyze the effectiveness of potential lower cost solutions. The study resulted in a feasibility report that summarizes and evaluates alternatives for reducing flooding potential and impacts on Hwy 41, Hwy 101, and Hwy 169.
Q: What is a floodplain?
Under state law, the floodplain is considered to be the land adjoining lakes and rivers that is covered by the "100-year" or "regional" flood. This flood is considered to be a flood that has a 1 percent chance of occurring in any given year.
The natural floodplain is an important part of our water system. It affects storm runoff, water quality, vegetative diversity, wildlife habitat, and aesthetic qualities of our rivers and lakes. Any alteration of the floodplain should be carefully evaluated. The least amount of alteration to the natural system is usually the most ecologically sound development decision. (Source: MnDNR) Learn more about floods, floodplains, floodways and flood fringes (PDF).
Q: What is the floodway?
The floodway is the land immediately adjoining the river channel that is the natural conduit for flood waters. The floodway must remain open in order to allow flood waters to pass. When the floodway is obstructed by buildings, structures, or debris, flood waters will be dammed up and will flood even greater areas. Large portions of the floodplain store and later release flood waters, which reduce river flood stages. (Source: MnDNR)
Q: What is the flood fringe?
The flood fringe is the remainder of the floodplain lying outside of the floodway. This area is generally covered by shallow, slow moving flood waters. (Source: MnDNR)
Q: What is flood stage?
Flood stage is defined as the elevation of a water surface in relation to a “datum,” or zero point. The National Weather Service defines flood stage as the river level that begins to affect life and/or property.
Q: What is floodplain encroachment?
Floodplain encroachment consists of placing any material below the base flood elevation (the 100 year high water elevation), and can be either transverse (crossing a waterway) or longitudinal (running along a waterway), or both.
Q: What is floodplain management?
Presidential Executive Order 11988 – “Floodplain Management” and Minnesota Statutes 103F.101 to 103F.155 require federal and state agencies, in carrying out their proposed projects, to provide leadership and action to reduce the risk of flood loss and minimize the impacts of floods on human safety by floodplains.
Q: During flood closures is it possible to use a ferry to carry vehicles and people across the river?
No. Due to the shallow water, debris and high flow rates during flooding conditions this is not a feasible option.
Q: Who else is involved in this project?
The Study Management Team (SMT) will meet monthly and serve as a communication link to constituents and elected officials regarding the study. SMT members include:
- Carver County
- Eden Prairie
- Hennepin County
- Jackson Township
- Louisville Township
- Metropolitan Council
- Scott County
Public comments were also solicited through formal meetings and electronic communications channels. Meetings were also held with environmental review and permitting agencies during the study period.
Q: What is the status of the proposed Minnesota River crossing project that will connect Hwy 169 and Hwy 212 in the vicinity of Hwy 41?
The project is still decades away (2030 or later). Construction funding is not currently included in MnDOT’s 20-year fiscally-constrained transportation plans. Right-of-way preservation funding is included, however, and can be used to acquire property in the corridor from willing sellers.