Abstract
This chapter is part of a larger report on the Chilko-Chilcotin River (CCR) system that analyzes physical and biological aspects of the watershed to provide insights on ecosystem functions and processes, highlighting the important role of Sockeye Salmon. The hydrology of the CCR system beginning at Chilko Lake and ending at the confluence with the Fraser River is described in detail. A conceptual model is developed that connects physical hydrologic elements to the watershed ecosystem.
The CCR system begins at the western boundary of the interior plateau of British Columbia and flows to the northeast before turning south and joining the Fraser River. Its climate is influenced by the Pacific Ocean and it experiences a rain-shadow effect from coastal mountains. Annual precipitation ranges from 1-2 meters/year in the mountains to <0.4 meters/year in the dry interior. The CCR system contains two major headwater lakes, Chilko and Taseko, which drain a portion of the eastern slope of the Pacific coastal mountains. These glacially created lakes act as buffers for perennial rivers, delaying the spring snowmelt pulse and reducing and broadening peak discharge. July and August usually produce the highest flows on the Chilko River ranging from 100 - 200 m3/sec, followed by low flows during the winter months of 5 - 25 m3/sec. The river network beginning at Chilko Lake has limited complexity with three major confluences in 195 km before emptying into the Fraser River.