Tsitika River Sediment Project

The Tsitika River Sediment Project began in 1991 to respond to concerns that sediment from the Tsitika River might negatively affect the killer whale rubbing beaches at Robson Bight Ecological Reserve.

The objective of the project was to develop a sediment budget for the entire Tsitika River watershed and use it to determine the amount of sediment that results from forestry-related activities.

Hydrometric stations were established at Russell and Catherine Creeks. These were intended to represent logged (Russell) and unlogged (Catherine) sub-basins of the Tsitika River watershed. Turbidity probes (used to measure the cloudiness of water) and sediment sampling equipment were added to an existing station at Tsitika River below Catherine Creek.

The data showed that ocean currents carried sediment from the Tsitika River away from the rubbing beaches. Despite this, concerns remained over the impact of forestry on fish habitats within the watershed. The research continued with a focus on creating sediment budgets within Russell and Catherine Creek watersheds.

The basaltic Karmutsen Formation underlies the entire Catherine Creek, whereas the lower two-thirds of Russell Creek is dominated by granitic bedrock. This made the creeks unsuitable to act as paired watersheds but provided the basis for comparative analysis of sediment production from the two bedrock types. It was decided that sediment budgets would be developed for Russell and Catherine Creek watersheds separately, beginning with Russell Creek.

Russell Creek watershed

In 2003, research within the Tsitika River watershed narrowed to focus only on the Russell Creek watershed. In co-operation with the University of British Columbia’s Faculty of Forestry, research began on subsurface preferential flow pathways at the hill-slope scale. The meteorological station network within Russell Creek was expanded to examine the spatial variability of precipitation and temperature within the watershed. In addition, work began on a study to assess the role of interception recovery in the rain-on-snow zone of the watershed.

The overall purpose of continuing research within Russell Creek watershed is to determine the effects of forest harvesting on water quality and quantity. Research related to sub-surface flow and canopy interception will be used in the creation of a hydrological model. When completed, the model will serve as a tool to aid in forest management decisions.

View the Russell Creek watershed (JPG, 250KB)  with snow lysimeter and meteorological station locations.

Research objectives

The project's objectives are:

• To determine the effects of contemporary forest management on sediment delivery to surface water
• To determine the effects of forest harvesting on peak flows in a watershed dominated by rain-on-snow events
• To maintain current infrastructure for long-term monitoring of stream flow and climate
• To use ongoing research results to validate a hydrological model that will assess the effects of forest management and climate change on streamflow

Publications

Research in the Tsitika River Watershed has resulted in a range of publications.