Jonathan Hilbert, Utah Valley University
The Jordan River in Utah has been highly regulated for many years through intense irrigation, channelization, and managed releases from Utah Lake. As the only outlet of Utah Lake flowing north into the Great Salt Lake, it is important to the riparian ecosystem and the surrounding human population as well. The river has a long history of mixed-uses, but it is emerging as a popular recreation site for the numerous adjacent communities. Human interaction on the individual and commercial scale influences the river through development and urbanization. The physical characteristics of the river and its riparian zone can be monitored to understand how the landscape is changing over time. In this study we focus on land cover changes in the riparian zone of the upper one-third of the river flowing out of Utah Lake to what is called “the point of the mountain”. This is the portion of the river that flows in Utah County. From aerial imagery and field observations, we noted alterations in the vegetation within the riparian zone from channelization, riprap, invasive species, or removal for a variety of reasons. We use GIS and aerial imagery to evaluate the land cover change on the Jordan River in Utah County between 1992-2011. Using Anderson’s classification system of land cover, specifically Urban or Built-Up Land, Agriculture, Vegetation, and Barren Earth, we quantified the changes in vegetation within a 100 meter buffer of the river’s wetted channel. While there are areas where little change is observed, areas of greatest change occurred downstream of the outlet, where a number of new communities have been developed in the last decade. As a subset of Vegetation we mapped changed in invasive species, tamarisk and reed canary grass, along the same section of the river within the riparian zone. Urban planning and invasive species removal along the river needs to be further considered as potential future recreation and restoration efforts are advanced on the river.