For many utilities, an essential component of assessing source water vulnerability includes an
evaluation of the impacts of changes in vegetative cover within source watersheds. In many parts of
North America, forested environments are critical source water regions; in those environments,
wildfires comprise significant land disturbances that greatly impact both water quality and
quantity in headwaters. In 2003, the Lost Creek wildfire impacted the upper Oldman River Watershed
in Alberta, Canada. It was one of the more severe recorded fires in the eastern slopes of the Rocky
Mountains. Many aspects of streamflow and water quality were impacted and have been studied during
five subsequent years of watershed recovery. The potential impacts of wildfire on drinking water
treatment were assessed by collecting and evaluating a comprehensive data set describing the basic
hydrology and water quality (turbidity, total phosphorous, total kjeldahl nitrogen, and dissolved organic
carbon) from source watersheds with varying degrees of land disturbance associated with wildfire
(unburned, burned, and post-fire salvage logged) over four years after the wildfire. Jar tests were
conducted to investigate the wildfire and salvage-logging associated changes in water quality and
quantity relative to unburned environments and their implications to drinking water treatment. The
observed vegetation and land use impacts on water quality of the Oldman watershed in Alberta, Canada
are representative of increasing pressures related to land use change in many regions of North America.
Compared to unburned watersheds, the observed increased turbidity, TP, TKN and DOC levels
observed in streams draining burned and salvage-logged watersheds present important economic,
logistical and operational challenges for water suppliers, managers and regulators. The data show that
such wildfire related changes in surface water quality can increase coagulant demand, sludge production
and oxidant demand/fluence requirements; they also can increase public health protection challenges
(potential increases in microcystins and DBPs). Accordingly, failure to manage and protect critical
source water regions will have significant cost and compliance implications that will influence the long
term sustainability of water management. Includes 21 references, tables, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 1.2 MB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 12 |
| Published : | 11/01/2008 |
