An Automated Framework to Identify Lost and Restorable Wetlands in the Prairie Pothole Region

While progress has been made in automating wetland identification, identifying lost and
restorable wetlands remains a challenge. A suite of automated methods was developed
and applied to the Nose Creek watershed near Calgary, Alberta to establish a historical
wetland inventory and the proportion of permanently versus temporarily lost wetlands. A
power-law function of wetland area vs. wetland frequency using wetlands derived from
the fusion of a high resolution digital elevation model and near-infrared data identified
permanent loss of 11.0% by number and 0.6% by area. The difference between historical
and existing wetlands was used to estimate a further temporary loss of 61.1% by number
and 78.3% by area. Historical wetlands lost to ditch drainage are easily restored by ditch
plugging. Therefore, an algorithm was created using digital terrain analysis that
distinguished drainage ditches intersecting wetlands using surface curvature. The 1,588
ditch-drained wetlands identified represent a potential recovery of 11.7% of the
temporary loss by number and 12.5% by area. Automated techniques to estimate wetland
loss and identify priority wetlands for restoration provide powerful tools for wetland
management.