The government says that adequate funds have been allocated over the years for fixing the local infrastructure. However, any funds do not seem to have reached the people who need it.
There is a quick, easy-to-implement way to fix this. We take advantage of the river running into James Bay, and bring in ships to serve as housing.
The oil and mining industries often have to deal with quickly providing housing and office areas in remote locations. Many companies take large barges or retired cruise ships, and renovate them for long-term living quarters. They contain restaurants, offices, water treatment systems, and medical facilities. Several of these vessels, including some currently sitting idle in Canada, are built for comfort in arctic regions, and have hulls that can withstand winter ice. One such vessel could provide comfortable cabins for 1,200 people, stopping the immediate suffering.
http://www.outlandcamps.ca/floating-accommodation/
http://www.bibbymaritime.com/our-fleet/bibby-renaissance.aspx
http://c-bed.nl/fleet
http://www.rodson.com/files/dn1091.pdf
In the medium term, we could move people from the floating hotels to ships retrofitted with larger apartments and school rooms. Browsing the internet, you can find retired cruise ships available for $3.5 million to $14 million, with cabins for 400-500 people. The cheaper ones require major engine overhauls, but it's fine even if we have to tow them to Attawapiskat. Pack them full of building supplies, have a tugboat haul them northwards, and provide local jobs renovating them to suit local needs.
http://cruiseship.homestead.com/sunshine.html
http://lageryachts.apolloduck.net/detail.phtml?id=283317
The ideal solution would be to provide proper housing and infrastructure on land - lower maintenance costs, and you don't have to worry about your housing sinking. Floating accommodations might plug the gap until we fix the current situation.