So the Cliff Notes version of NAWS and the Red River Valley Water Supply Project.
NAWS is a federally sponsored project being funded through the U.S. Bureau of Reclamation. Because of the treaty between Canada and the U.S. and the funding source being federal, there is indeed a requirement of sorts (Canada's insistence) that water coming from the Missouri River into the Hudson's Bay drainage be treated to prevent the spread of Aquatic Nuisance Species, to include things like whirling disease and paddlefish (I kid you not, they actually listed paddlefish as a concern). Canada's position on this was one of the water needing to be treated to the nine 9's, that is 99.9999999% free of any living biota. This is, and always has been, a very disingenuous position of Canada's since that is MUCH higher than you get out of any drinking water faucet in either Canada or the United States. They don't seem to mind that water from the Milk River (a Missouri Tributary) is diverted into Hudson's Bay drainage for their benefit, and that is done with zero treatment.
The Red River Valley Water Supply Project started out much like NAWS in the sense that it was a part of the original agreement between the federal government and the State of North Dakota as a reach around for ND hosting so much of the Lake Sak and Lake Oahe projects. That river bottom land was considered very valuable, but after the dustbowl drought, ND was anxious to acquire a steady, or at least a dependable backup water supply for the RRV. Canada, Missouri, and Minnetucky all fight tooth and nail to prevent ND from supplying water to the RRV, each for their own reasons that they will usually not admit to. Missouri is arrogant and thinks the Missouri River belongs to them, so they fight any withdrawals from the Missouri because they want to be able to exert and unusually large influence on water projects that may hinder their precious barges. Canada, much like Minnetucky, fights any export of water from the Missouri to the RRV because they've gotten on their high horse and think it will be the end of the world. Yet they were still importing rainbow trout from SD even though SD has whirling disease, but then they turn around and claim whirling disease (or some other yet undescribed virus) will devastate their fisheries. Their position is well entrenched at this point. Minnetucky is far more insidious when it comes to supplying water to the RRV. If you look up and down the Red River, you will notice that the ND cities are much larger than their Minnesota sister cities. Wahp/Breckinridge, Farhole/Moorhead, GF/East GF, etc. The most likely reason this is true is because if you have to live in the RRV...most people generally find ND more to their liking, especially if you are going to build a BUSINESS. So, one of the things we have seen take off in the RRV over the past decade or more is the growth in water intensive agricultural processing. Minnetucky can't compete in the business world with most of these projects because of their onerous MN-DNR, MN-Health Dept, etc, etc. In order to attempt to lure these industries over to MN, the one thing they can offer is a fairly secure water supply, yep...I've been to the meetings and seen their scientists and politicians be very disingenuous in their objections to ND supplying water to the RRV.
I actually worked for Reclamation back when they were doing all the environmental and engineering studies for the RRV water supply. All that work has now been sitting on the desk of the Secretary of the Interior who has to sign off on the preferred alternative. No Secretary has been willing to do that, so it just sits and collects dust. Fast forward to the past few years and ND has basically said f*&k it and is going to go with some bastardization of the Missouri alternative. Since it is no longer a federally funded project (so far as I know), that may relieve the State from the need for a biota treatment plant for water eventually sent east. BTW, it is going to end up in the Sheyenne River which is STILL a part of the RRV and even Hudson's Bay drainage. This would suggest that if there is no federal requirement for a biota treatment plant akin to the one planned for up by Max, it is possible that there will be two diversions from the Missouri River into the Hudson's Bay drainage, one with a water treatment plant before the water crosses the divided, and the other without.
Of course, I no longer work for Reclamation, so my understanding on the finer points of the above are a little dated at this point and there may indeed be some plan for a treatment plant on the RRV diversion, I just have not run across anything mentioning it in detail. I am quite sure if there is no treatment plant, there will be plenty of lawsuits from Canada and Minnetucky, and their favorite judge in DC is not known to be a friend of North Dakota.