[2] Avonlea Creek is a main tributary of the Moose Jaw River, which is part of the Upper Qu'Appelle Watershed[3] and the Hudson Bay drainage basin.

From there, it travels in a north-westerly direction past Parry, paralleling the Moose Jaw River until it empties into the Watson Reservoir, south-east of the village of Avonlea.

The headwaters of the river are in the Missouri Coteau[4] and The Dirt Hills to the west are the source of several tributaries.

The dam was originally built by the Prairie Farm Rehabilitation Administration and is now operated by the Saskatchewan Water Security Agency.

The dam is 16.6 metres (54 ft) high and the reservoir holds 7,400 dam3 (6,000 acre⋅ft) of water and has a surface area of 201.5 hectares (498 acres).