Salish Sea Ecosystem Conference

Managing Active Forestry Lands for Increased Water Retention – A New Approach for Protecting Summer Water Supplies

2016SSEC

The Salish Sea is connected to the land and human communities that make up the watersheds that drain into it. At the same time that the Salish Sea is facing pressure due to our land use management choices and the impact of climate change our human communities are facing hotter summers with the looming of droughts and decreasing summer water supplies just over the horizon. The summer of 2015 was an early warning of this future. For my master’s thesis I have been looking at the connections between our working lands and summer water supplies. Specifically I have been exploring how clear cut lands can be actively managed after the harvesting of the timber in order to increase water retention on site. This has involved establishing a system of bioswales and controls with soil moisture sensors to monitor the effectiveness of these swales on increasing water retention within the clear cut site. My research site is located in a recent clear cut site within the University of Washington Pack Forest. While on the edge of the watersheds that drain into the Salish Sea the potential benefit of the approach that my research is looking at would apply across the Salish Sea. The preliminary results from my research indicates that swales can be an effective means for actively managing clear cuts to retain water. Clear cuts have been shown to cause summer minimum flows to be reached earlier in the season adding to the impact of climate change on these flows. My research indicates a possible strategy for actively managing clear cuts to counter these impacts. In a future that will be defined by drought new approaches will be necessary to ensure adequate summer water supply for human communities and for the ecosystems of the Salish Sea.