Canadian Forest Service Publications
Travel times for snowmelt-dominated headwater catchments: Influences of wetlands and forest harvesting, and linkages to stream water quality. Leach, J.A., Buttle, J.M., Webster, K.L., Hazlett, P.W., Jeffries, D.S., Wiley Hydrological Processes. 2020;34:2154–2175.
Issued by: Great Lakes Forestry Centre
Catalog ID: 40319
Series: Miscellaneous Report (GLFC - Sault Ste. Marie)
Availability: PDF (download)
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Plain Language Summary
The time it takes water to travel through a watershed, from when it enters as rain and snow, flows through soils, and ultimately leaves as streamflow, can strongly influence stream water quality. It is well established that harvesting mature trees changes the water balance of a watershed, primarily by decreasing how much water is transpired back into the atmosphere by vegetation. However, it is less clear how forest harvesting might change the time water spends in the soil and what this might mean for how stream water quality responds to harvesting. To address this knowledge gap, we used 30 years of chloride measurements (a naturally occurring water tracer) in rain, snow and streamflow from 12 forested watersheds in the Turkey Lakes Watershed Study to estimate the average time water spends in these catchments. Three of the watersheds were harvested in 1997, which provided an opportunity to assess how water travel times change following harvesting. We found that all three harvested sites saw water spend a shorter amount of time in the watershed, compared to unharvested sites. Because water is spending less time in the watersheds following harvesting, it has less opportunity to chemically interact with soils. These harvesting-induced changes in hydrology help provide mechanistic explanations for some of the water quality changes typically seen following forest harvesting.