| To better understand water quality changes and trends in Alberta streams, Alberta Agriculture staff working on the AESA (Alberta Environmentally Sustainable Agriculture Program) Stream Survey Project, are looking at the land cover and agriculture management practices adjacent to streams.
Previous studies in Alberta have shown that agricultural practices can contribute nutrients, pesticides and bacteria to surface waters. "As water quality changes over time, it becomes increasingly important to understand why the changes occur," explains Cherie Westbrook, Water Quality Biologist with Alberta Agriculture, Food and Rural Development. "We need to know if the changes are the results of changing land management practices or other influences."
In the summer of 2000 a pilot project was initiated to sample points of different land cover types in four watersheds. In 2001, the project expanded to include ground truthing sample points in each of the 23 AESA Stream Survey watersheds. Each sample site location was documented with GIS (geographic information system) using global positioning systems (GPS) and satellite technology. "We are using this 'ground truthing' information to calibrate the satellite imagery data we've purchased, and to confirm the actual land cover in the watershed," says Westbrook. "We were looking to confirm the type of crops or pasture or other land cover."
This information, combined with the long-term water quality stream sampling project, will provide information for protecting water quality. "We plan to update the land cover information every four years to coincide with the federal census data," says Westbrook. "Then we will have a quantitative estimate of land cover, and how that land cover changes from every block of four years to four years."
Land cover information is collected on each of the 23 AESA Stream Survey watersheds
Biologists at Alberta Agriculture will link the land cover information to the AESA water quality stream survey results to help explain observed water quality trends. For example says Westbrook, if stream water quality in a watershed has not changed over the past five years, but the amount of cropped land has significantly increased, then producers in the watershed are doing a pretty good job of protecting their surface water.
"We're pretty excited about this research, especially because it's fairly innovative and not often done," says Westbrook. "We think this information will be very important for being able to create long-term land management plans that work for individual operations." The first water quality trend report is being compiled and will be released next fall, and every five years after that. |