Lower Belly River Fish Assemblage Activity Report 2009
The Belly River is a major watershed in southwestern Alberta that flows 181 km from the US/Canada international boundary to its confluence with the Oldman River. Historically, the Belly River was presumed to be a cold‐water river that supported several cold‐water fish species, such as trout and whitefish (English 1995). Since that time it is believed that the cold‐water fishery has been restricted to the headwater reaches, as a result of major water withdrawals for domestic and agricultural purposes.
Irrigation is the major consumptive‐use responsible for reducing instream flow in the Belly River. To accommodate the region’s high water demand, the Belly River is managed as an irrigation water source and supplies water to several water pump stations and three major on‐stream water diversions. These water withdrawal devices are the main cause of reduced instream flows in the Belly River. Current water management practices regulate the Belly River withdrawals to maintain a minimum flow requirement of 0.93 m3/sec.
The minimal flow requirement is a water conservation objective intended to ensure necessary volume and quality of water for the protection of the natural waterbody and its aquatic environment. Prior to 1990, minimal flow requirements were not regulated and the effects of water withdrawal from the Belly River were exacerbated. Following the amendment of Alberta’s Water Act, effective January 1990, several water licenses were amended and coordination between water management organizations was established to ensure the Belly River maintains a minimum flow rate (Dave Hunt
Presently, water withdrawals and diversions for irrigation negatively affect stream flow dynamics in the Belly River although things have improved since imposition of minimal flow requirements in 1990. The major limiting factors associated with water withdrawal are habitat loss and increased water temperatures which have decreased the river’s capacity to support a cold‐water fishery in all sections but the headwaters of the Belly River (English 1995). During critical periods, water withdrawal and diversion are suspected to limit the river’s capacity to support any fish population in the lower Belly
Few fishery assessments have been conducted on the Belly River and the studies that were conducted in the river are outdated, so the current status of the fishery is uncertain. In 1980, a biological inventory was completed on the Belly River. The objectives of the study were to provide an inventory of fish habitat features and to determine the effect instream flow reduction has on the river’s water quality and biological systems. Backpack electrofishing equipment was used to collect fish data at critical periods when limitations to fish habitat were most severe.
It is suspected that the impact of flow reduction on fish populations is greatest in the lower Belly River which is also impacted by the cumulative effects of upstream land‐use practices. The Alberta Conservation Association in collaboration with Alberta Sustainable Resource Development – Fish and Wildlife Division, Alberta Environment and Department of Fisheries and Oceans, conducted a fishery assessment to describe the fish assemblage in the lower Belly River. The objectives of the study were to determine the species composition, fish distribution, and abundance, and fish habitat use of the fish population in the lower Belly River. Data collected from this study was compared with
results obtained from the 1980 biological inventory.