Schedule E of the Master Agreement on Apportionment establishes water quality objectives for various variables at 11 PPWB rivers. These PPWB objectives promote cooperative water quality management. They are guidelines which the board can use to assess whether the water in a particular river is acceptable. The objectives also help in assessing the impact of proposed developments on water quality and enable the PPWB to identify potential interprovincial water quality issues.

The objectives apply to specific river reaches crossing the Alberta-Saskatchewan and Saskatchewan-Manitoba borders. Water quality is sampled by Environment Canada at 12 PPWB sites, 11 of which have PPWB objectives (see Where We Monitor). The PPWB then compares the sampled amounts of water quality parameters to the PPWB objectives, assessing whether water quality conditons are acceptable.

If monitoring indicates an objective is not being met, the Committee on Water Quality - a permanent committee of the PPWB - will investigate to determine the cause, and whether there is a risk to downstream water users. The committee will closely study the cause of the condition and decide whether it is a one-time or a long-term event.

Finally, the Board may make recommendations to the upstream province in which the event occurred. The appropriate agency then takes whatever corrective action is required.