An independent Alberta would control all the water in its rivers.
Claimed by: Implied by sovereignty arguments over natural resources
False: False as written according to the settled evidence. How we rate.
Summary
Most of Alberta's major rivers flow east into Saskatchewan and Manitoba, and Alberta has agreed to share that water. Under the 1969 Master Agreement on Apportionment, signed by Canada, Alberta, Saskatchewan and Manitoba, Alberta may consume at most half of the natural flow of each eastward-flowing transboundary river and must let the other half pass downstream. For three creeks near the United States border the share Alberta must pass on rises to 75 percent to meet international commitments under the Boundary Waters Treaty. Independence would not erase those obligations: downstream provinces and the United States would still expect their share, and water-sharing is one of the things a new country would have to negotiate, not something Alberta could simply seize.
Evidence
Under the Master Agreement on Apportionment, Alberta is entitled to 50 percent of the natural flow of a transboundary river before it enters Saskatchewan and must allow the remaining 50 percent to pass downstream.
For Battle, Lodge and Middle Creeks, Alberta must pass 75 percent of the natural flow to Saskatchewan to accommodate international water-sharing commitments with the United States.
The agreement is administered by the Prairie Provinces Water Board and exists so the prairie provinces and Canada share interprovincial waters equitably.