Impacts of Climate Change on River Systems
We are able to see aspects of climate change though data collected from organizations like NASA GISS. But how can we measure the impacts to river systems? Other impacts like rising sea level and melting ice are very visible changes. And while some aspects of climate change are easy to see in river systems, like flow; to understand all of the impacts climate change has on river systems more detailed analysis needs to be performed.
Monitoring
References
Erwin, M. L., & Hamilton, P. A. (2005, May). USGS: Science for a changing world. Retrieved from Monitoring Our Rivers and Streams: http://pubs.usgs.gov/fs/fs-077-02/
King, A. J., Tonkin, Z., & Mahoney, J. (2009, December). Environmental flow enhances native fish spawning and recruitment in the Murray River, Australia. River Research and Applications, 25(10), 1205-1218.
Neitsch, S., Arnold, J., Kiniry, J., Srinivasan, R., & Williams, J. (2002). SWAT Soil & Water Assessment Tool. Retrieved from Soil & Water Assessment Tool User's Manual: http://swat.tamu.edu/media/1294/swatuserman.pdf
Models
To improve on the analysis from the USGS stations, models can be used. One model in particular that is often used is the Soil Water Assessment Tool or SWAT model. This model takes multiple layers of characteristics like land use, elevation, soil type, slope, reach (river) files, and monitoring stations into account along with data from the field; with all of these inputs, results for entire watersheds can be calculated (Neitsch, Arnold, Kiniry, Srinivasan, & Williams, 2002). This allows for the expansion of the regions that can be analyzed. Using models also allows us to run different scenarios to represent the different possible conditions in the future. Running different scenarios allows for predictions of what may occur, providing decision makers values they can use to insure that resources will be used in ways that supply our current needs as well as those of the future.
A recent use of SWAT models and watersheds has been to develop environmental flows. Environmental flows can be described as the patterns and quantity of water flow needed to support aquatic ecosystems as well as the needs of humans (King, Tonkin, & Mahoney, 2009). Environmental flows are desired because they can be designed to fit the use of the river, for instance a river that is used for trout will have a flow pattern based off what trout need to survive, this includes peak flows and flood events at specific times during the year. While environmental flows don't stop the impacts caused by climate change, it gives the aquatic systems the best chance for survival while insuring we have enough water to grow crops and drink.
Monitoring Stations
Agencies like USGS provide initial analysis and monitoring or river systems by designing and implementing river gauges. These stations collect data about the flow, chemical composition, and temperature of the rivers in which they are stationed (Erwin & Hamilton, 2005). This allows for remote access to regions of streams via computer, removing the need to send individuals out and gather data for years before analysis can occur. However, the analysis provided in this manner is limited to the number of stations implemented as well as the amount of data being collected.
