Water temperatures exceed criteria for water quality and fish habitat. Water temperatures within the watershed need to be reduced by 2 to 5 degrees Celsius to meet standards.
High summer water temperatures may result from increased stream width-depth ratios; diminished baseflow due to water withdrawals, reduced groundwater recharge, or unstable channel conditions; and reduced canopy cover due to levee development, road encroachment, and agricultural activity. Elevated summer water temperatures tend to concentrate the distribution of juvenile steelhead to stream reaches benefiting from spring, or groundwater recharge, thereby reducing ‘available’ habitat to a fraction of the watershed’s habitat potential.
Treatments designed to address lack of riparian vegetation and canopy cover, unstable banks, channel conditions, and lack of holding capacity (retention) can all have a positive impact on stream temperature while also helping address other limiting factors like loss of terrestrial an aquatic habitat.
Objective 1 – Reduce Stream Temperature
One of the three objectives identified in the Restoring Anadromous Fish in the Lapwai Creek Watershed plan is to reduce stream temperature.
Improve Riparian Condition: This deliverable will provide the largest benefits to the reduce instream temperature objective.
In order to meet this objective one deliverable or treatment was identified:
Deliverable 1 – Improve Riparian Condition