Minneapolis STRIB's coverage of the meeting

The Thursday night watershed meeting was like no other I have ever been to. The MAC had their consultants explain that they were going to use the jet grouting method to seal off the construction sites for the tunnels, (The tunnels are to allow vehicles to drive under the runway to access the land on the inside of the airport property). instead of the metal grates. The main difference is that the concrete grouting is permanent, but no more so than the tunnel itself. This method is also considerably cheaper than the metalgrates.

The consultant explained that the grouting will allow them to patch the wall once it is in place. This means that if the wall leaks that they can simply add more concrete grouting to fix it. The way they will check the wall to make sure it is holding, is that they expect no more than 900 gallons a minute pumping rate to empty the trench that will be dug for the tunnel. Some water will leak into the construction site under the concrete wall, but it will not be 900 gallons a minute. That figure is only to pump the trench dry the first time. Once they pump it dry, the concrete wall will stop almost all the water around the trench from leaking in. Then the MAC will also monitor various wells around the construction site to make sure that the water levels in the area do not drop. One of the wells is at Camp Coldwater.

The Minnehaha Creek Watershed asked for assurances that the water levels be protected, even if the concrete wall completely failed. Jeff Hamiel, executive director and official spokesman of the MAC, said in no uncertain terms that they intend to protect the water resources of the area. If the wall completely failed or had extensive leaks, Hamiel said the project will stop, and they will have to figure out another way to continue without the drastic dewatering first proposed. Lynn Levine came up to the microphone and asked for Hamiel to further state his position to be absolutely clear on what the MACís position is, explaining that we have been tricked before. Hamiel came back and said that even if the wall fails and it would completely submerge the equipment and cause extensive damage to the construction site, they will not drain the water to the Minnesota river to try and keep it dry. Instead they would let it all go underwater and figure out a way to fix the situation at that point.

The consultant said he did not think that this would happen, as when they pump the trench dry the first time, if it requires excessive pumping they will know that the wall is leaking and will fix it before anything else happens. It was such a surprise to hear the MAC give such a guarantee that they will do the right thing, people around me were noting the time was 8:22PM in case they had to reference the statement at a latter date. After all the problems with MnDOT, it appears that the MAC has come in and, in the end, shown how to make a commitment to correct the situation to protect outside water resources from their project area. We will have to see if MnDOT can now duplicate this effort in their construction of the Hwy 55 & 62 interchange. It appears that the drainage pond for the road will have a bottom that is two feet lower than the Coldwater Spring. An elementary understanding of gravity will show how this could permanently dewater part of the Coldwater Spring (up to 25%). This is now the most immediate danger to Coldwater.

The Minnehaha Creek Watershed is looking into this situation to try and figure out the impact. The problem is that wile the Coldwater area is in the Minnehaha Creek Watershed, because of the political decision of the Board of Soil and Water Resources, the highway interchange, that sits over part of the source water for the Coldwater Spring is in the Lower Minnesota River Watershed District, who has no permitting authority. The Next Lower Minnesota River Watershed meeting is on Wednesday, September 20th at the Shakopee Community Center at 7PM... Minnehaha Creek is trying to Work with Lower Minnesota to figure out the risks and how to correct the situation. We have not yet heard of a response from MnDOT.

Minneapolis STRIB's coverage of the meeting