The 2011 report compiles data on landscape change, allocations/uses, quality, quantity and risks for the South Saskatchewan River Sub-basin. It documents licensed allocations of ~288 million m³ in 2010 (97% surface water; 59% municipal, 26% agriculture, 11% industrial/commercial), with Medicine Hat’s licence elevated due to its power plant. Estimated actual use in 2005 was ~66 million m³ (~32% of licensed), led by irrigation (42%) and industrial (26%), with municipalities ~12%.
Water quality on the mainstem is largely set by inflows from the Bow and Oldman; since 1998, the River Water Quality Index has been “Good” overall, but nutrients and pesticides often rate only “Fair/Marginal.” Tertiary upgrades (e.g., Calgary/Lethbridge) have reduced dissolved phosphorus, though stormwater-borne phosphorus remains a challenge.
Quantity trends are concerning: despite strong year-to-year variability, mean annual flow at Medicine Hat shows a significant downward trend linked primarily to upstream consumption/diversions. The basin has also seen extremes, including the June 2010 flood (e.g., SSR peak ~2,300 m³/s; Seven Persons Creek ~135 m³/s). Meanwhile, Medicine Hat’s mean annual temperature has risen ~1 °C since 1895, intensifying pressure on supplies.
SEAWA frames indicators (flow, water-quality metrics, riparian condition, groundwater/wetlands, land use, ag intensity, fish) for adaptive management and public reporting—intended to guide actions like wastewater and stormwater controls, riparian protection, and best practices in agriculture.