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.

Q: Why not just build the road higher than the flood elevation in order to prevent seasonal closures?
Problems can occur when you raise a roadway within a floodway. The effect of raising a roadway’s elevation is the same as creating a dike.  Even though the water would still be redirected to go through the bridge, the water still backs up and properties upstream of that road may be affected. How extensively the water will back up and how far it spreads can only be determined using hydraulic models. To ensure the water doesn’t flood new areas upstream, a relief structure needs to be built to accommodate the volume of water that would normally have flowed over the lowest points on the road.

A “back of the envelope” method for determining how much area is needed for a relief structure is to simply look at how much area the water used when it was going over the road.  For example, at Hwy 41, 2,500 feet of roadway go under water. If, at flood, it is two feet deep, then you will need 5,000 square feet of opening (the equivalent of 50 10-foot x 10-foot box culverts, or a bridge that’s 20 feet high and 250 feet long). A review would then need to be done to verify whether either of the two structures are even feasible at this location. If they are feasible, then we would need to review whether the roadway approaches to the bridges need to be modified.
Cost is not the only factor in the decision making process, as the environmental impacts will greatly influence the feasibility to do this.

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: What preparations are being taken to address the potential spring flooding this year?
In a step to help ease congestion and improve mobility in the event that flooding forces the prolonged closure of Hwy 101 and Hwy 41, plans are ready to accommodate a greater volume of U.S. Hwy 169 traffic between Shakopee and I-494.
For the latest information, please visit http://www.dot.state.mn.us.

Q: What is the purpose of the study?
The study’s purpose is to investigate feasible transportation solutions to the seasonal flooding in the Minnesota River Valley in the southwest metro. It focuses on the bridges and approach roadways over the Minnesota River for Hwy 41, Hwy 101 and Hwy 169.
The study will determine what capital improvements would be necessary to minimize roadway closures and/or add capacity during flood events. Hwy 41 and Hwy 101 alternatives will likely focus primarily on elevating roadway profiles. Hwy 169 alternatives will primarily be related to adding capacity with and without widening existing bridges.

Q: Why do we need a study?
Spring flooding frequently closes the Hwy 101 and Hwy 41 Minnesota River crossings, which have 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 traffic detoured during closures at the Hwy 41 and Hwy 101 river crossings. While a long-term replacement solution has been identified for the Hwy 41 river crossing, it will be decades before that crossing is replaced given current funding levels.

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.

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: What is the project schedule?
The study will take place through August 2011 and will include the following key elements:

• Stakeholder and public involvement
• Hydraulic model development and analysis (including bridge analysis)
• Traffic analysis
• Potential design alternatives and analysis

A feasibility report will be prepared that summarizes and evaluates a range of alternatives for reducing flooding potential and impacts on Hwy 41, Hwy 101, and Hwy 169.

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:

Meetings will also be held with environmental review and permitting agencies during the study period.

Q: How can I get involved in this project?

• Check www.dot.state.mn.us/metro/floodstudy regularly for updated information.
• Come to the open houses to ask questions and provide input. You’ll learn about the study process, key issues in the study area, project need, and the conceptual alternatives and their associated impacts. Two public open house meetings will be held through August 2011. Sign up for email updates and we’ll send Open House invitations and project updates directly to your inbox.
• Send your comments and concerns to the MnDOT project representatives (see below).
• Sign up for email updates. You’ll get meeting notices and study updates sent directly to your e-mail inbox.

Q: Who can I contact to get more information?

Send an email, call or write us.

Kirsten Klein
Communications and Public Affairs
MnDOT, Metro District
Phone: 651-234-7506
Email: kirsten.klein@state.mn.us

 

Kristen Zschomler
Phone: 651-234-7723

MnDOT Metro District
1500 West County Road B2         
Roseville, MN 55113

Email: kristen.zschomler@state.mn.us