| dc.description.abstract | The Alberta Wetland Inventory (AWI), which is used in a variety of applications
across the province to estimate wetland cover from aerial photographs, detected only
34% of confirmed wetland field plots in boreal forest watersheds in the Swan Hills of
Alberta. Given the association between wetland cover and runoff and surface water
chemistry in western Canadian boreal forest (Boreal Plain) watersheds, accurate
quantification of wetland cover is critical to efforts to model hydrologic processes and
water quality. Therefore, as a component of the Forest Watershed and Riparian
Disturbance (FORWARD) Project, the Wetland Inventory and Identification Tool (WIIT)
was developed and successfully detected 81% of the wetland field plots. Application of
both models across a variety of landscapes in the boreal forest of Alberta demonstrated
that wetland cover estimates were 1.5 times higher with the new WIIT model than with
the AWI. Also, the WIIT identified polygons that were both smaller and contained taller
trees than those identified by the AWI, indicating that this computer model may be more
effective than wetland identification methods that use only aerial photography. Results
of this study show that careful interpretation of aerial photography at the 1:15 000 scale,
coupled with ground truthing and computer models, can provide an accurate means of
identifying wetlands on Boreal Plain landscapes.
A preliminary annual (November through October water year) water and
phosphorus (P) budget was also constructed for a 3-ha peatland in the Swan Hills, to
quantify some aspects of peatland water and P cycling. Understanding the relationship
between wetlands, and water and nutrient (P) inputs and outputs from watersheds is
central to models being developed for stream water quality and quantity. The study
wetland in the FORWARD Willow watershed retained 27% of the water collected
through rainfall and runoff, and evapotranspiration represented the dominant route for
water loss from the wetland, constituting 63% of rainfall inputs. The wetland retained
(within soils, vegetation and microbial pools) approximately 77% of P entering the
wetland via wet and dry atmospheric deposition and runoff. | |
