Given the prevalence of overexploitation of fish and the resulting endangerment of many aquatic species particularly fish, that exists in society today, it is of great relevance and importance to study the effects of this Project’s development on the regional aquatic species. While the fish population in Lower Churchill has been stable for the past 35 years and no species is currently listed as endangered under SARA (Species at Risk Act), COSEWIC (Committee on the Status of Endangered Wildlife in Canada), or NLESA (Newfoundland Endangered Species Act) (Nalcor 2009, Vol. 2A), it is important to analyze the methods employed by the proponent, particularly in terms of assessment and mitigation to ensure that the fish will not have unnecessary or avoidable dangers imposed on their habitat. This assessment of aquatic environment impacts will focus on fish habitat changes, incidence of fish entrainment, and bioaccumulation of Methyl-Mercury.
Existing Environment and Species Present
The Churchill River system is highly influenced by the Churchill Falls Power Station, which controls 75% of the total drainage area of the Churchill River. All water is discharged into Lower Churchill once it passes through the Churchill Falls turbines (Nalcor 2009, Vol. 2A). The Lower Churchill River watershed is characterized by a well-defined drainage pattern, steep tributary slopes, and little natural storage in lakes and bogs. The watersheds are reflective of both the Power Station’s operations as well as regional climate - inflows are highest in the spring and lowest in late winter (Nalcor 2009, Vol. 2A). The Mean Annual Flow (MAF) through Churchill Falls is 1,390 m^3/s and the MAF for Gull Island and Muskrat Falls is 1,780 m^3/s and 1,840 m^3/s respectively (Nalcor 2009, Vol. 2A). From Churchill Falls to Gull lake, the Lower Churchill River flows through a single, mostly straight channel, but as the river reaches Winokapau lake, the stream area widens and begins to include more slopes, sandbars, and deltas (Nalcor 2009, Vol. 2A).
Though the general trends of lineation in this region of Labrador are North to South and Northwest to Southeast, Gull Island predominantly experiences a trend from East to West and Northeast to Southwest. Furthermore, from Gull Island to Muskrat Falls, the river is slightly more winding than the upstream portions from Churchill Falls to Gull Island (Nalcor 2009, Vol. 2A). This information contributes to the findings indicated by river data that this system is somewhat atypical. The measured velocities are much higher than those usually seen in classical freshwater systems (Nalcor 2009, Vol. 2A).
The most prevalent species in the Churchill River include the longnose sucker, lake whitefish, brook trout, white sucker, ouananiche (atlantic salmon) and northern pike. Other less prevalent species include the longnose dace, lake chub, burbot, and the round whitefish (which is considered rare) (Nalcor 2009, Vol. 2A). Though the fish in this system benefit from the regulation of river flow provided by the Churchill Falls Power Station, they reside in a system that provides atypical habitat availability due to the still high flow velocities. However, it has been determined that the fish have adapted to the current environment in the Lower Churchill River over the past 35 years and their populations have been consistently stable during this time period (as is mentioned earlier) (Nalcor 2009, Vol. 2A).
Existing Environment and Species Present
The Churchill River system is highly influenced by the Churchill Falls Power Station, which controls 75% of the total drainage area of the Churchill River. All water is discharged into Lower Churchill once it passes through the Churchill Falls turbines (Nalcor 2009, Vol. 2A). The Lower Churchill River watershed is characterized by a well-defined drainage pattern, steep tributary slopes, and little natural storage in lakes and bogs. The watersheds are reflective of both the Power Station’s operations as well as regional climate - inflows are highest in the spring and lowest in late winter (Nalcor 2009, Vol. 2A). The Mean Annual Flow (MAF) through Churchill Falls is 1,390 m^3/s and the MAF for Gull Island and Muskrat Falls is 1,780 m^3/s and 1,840 m^3/s respectively (Nalcor 2009, Vol. 2A). From Churchill Falls to Gull lake, the Lower Churchill River flows through a single, mostly straight channel, but as the river reaches Winokapau lake, the stream area widens and begins to include more slopes, sandbars, and deltas (Nalcor 2009, Vol. 2A).
Though the general trends of lineation in this region of Labrador are North to South and Northwest to Southeast, Gull Island predominantly experiences a trend from East to West and Northeast to Southwest. Furthermore, from Gull Island to Muskrat Falls, the river is slightly more winding than the upstream portions from Churchill Falls to Gull Island (Nalcor 2009, Vol. 2A). This information contributes to the findings indicated by river data that this system is somewhat atypical. The measured velocities are much higher than those usually seen in classical freshwater systems (Nalcor 2009, Vol. 2A).
The most prevalent species in the Churchill River include the longnose sucker, lake whitefish, brook trout, white sucker, ouananiche (atlantic salmon) and northern pike. Other less prevalent species include the longnose dace, lake chub, burbot, and the round whitefish (which is considered rare) (Nalcor 2009, Vol. 2A). Though the fish in this system benefit from the regulation of river flow provided by the Churchill Falls Power Station, they reside in a system that provides atypical habitat availability due to the still high flow velocities. However, it has been determined that the fish have adapted to the current environment in the Lower Churchill River over the past 35 years and their populations have been consistently stable during this time period (as is mentioned earlier) (Nalcor 2009, Vol. 2A).