| Abstract/Description or Keywords |
The Nechako River is one of the major tributaries that affect flow and water quality in the Fraser River. Its headwaters are located in the Nechako Reservoir drainage basin. The drainage area of the river at Prince George is 46,000 km2. The Nechako River water quality is influenced by the water quality from the Stuart, Nautley, and Chilako rivers. Nechako River water is used for irrigation, livestock watering, primary and secondary-contact recreation (i.e., swimming and boating), drinking water with partial treatment, by wildlife, and to sustain aquatic life. Based on regular water quality monitoring of the Nechako River at Prince George, we concluded that: Š There were no environmentally significant trends in water quality. Š Site-specific water quality objectives for ammonia, nitrite-N, and pH were met. Š Fecal coliforms probably met the objective to protect drinking water with partial treatment at Prince George. More frequent monitoring (i.e., five to 10 samples in 30 days) is required to improve the comparison to the objective. Š All phenol values exceeded the guideline to prevent fish tainting. However, the phenol was naturally occurring and fish tainting is not known to be a concern in the Nechako River. Š The drinking water (aesthetics) guideline for water temperature (15 °C) was exceeded in 86% of the samples collected between June and September during 1985-95. However, the water was warm enough for primary-contact recreation (e.g., swimming) at these times. The maximum guideline (22-24 °C) for adult and juvenile salmonids was exceeded once. Š Water hardness was lower than the optimum range for drinking water, but was still quite acceptable. Š The river had a low sensitivity to acid inputs. Š Elevated non-filterable residue and turbidity may have been due to natural erosion within the Nechako River basin during spring freshet, augmented to an unknown extent by non-point sources such as forestry and agriculture. Š Nechako River water at Prince George must be treated to remove turbidity prior to drinking. Š Several metals had levels above aquatic life or drinking water guidelines when suspended sediments (non-filterable residues or turbidity) were elevated. This indicates that the metals were in a particulate form, probably not biologically available, and would be reduced by drinking water treatment to remove turbidity. We recommend that monitoring be continued on the Nechako River at Prince George. Water quality data collected at this site would be used to: _ represent the water quality from the upper portion of the interior plain ecosystem, _ check attainment of site-specific water quality objectives, and _ determine changes in the water quality of the Fraser river basin downstream from the Nechako River confluence. |
