Grand Valley River Corridor's Fluvial Opportunity Zone

 Joel Sholtes1*, Molly Guiney2

1Joel Sholtes, PhD, PE Wash Water Science and Engineering, LLC, Grand Junction CO
2Molly Guiney, MS, Jacobs, Seattle Washington

The Colorado and Gunnison Rivers within the Grand Valley naturally migrate across their floodplains and down valley. This sometimes gradual, sometimes episodic migration leaves behind a rich tapestry of geomorphic forms within the floodplain including side channels, oxbow lakes, and mid-channel bars and islands. Channel migration and resulting geomorphic complexity supports various life stages of endangered fish and creates and sustains native riparian vegetation. It also interacts with and sometimes finds itself in conflict with human development and infrastructure.

The fluvial geomorphic hazard (and opportunity) zone (FHZ) along the Colorado and Gunnison River corridors delineates the zone within which natural processes of channel migration as well as fluvial influence on valley margins may occur. Through this mapping process we:

1. Identify river corridor hazards in addition to inundation hazards identified by FEMA floodplain maps and communicate these hazards to the community.

2. Bring information regarding dynamic river processes for planning and management of infrastructure and development.

3. Identify opportunities for floodplain restoration and areas to allow migration, resulting in ongoing creation and maintenance of floodplain and riparian habitat for Endangered Species Act (ESA) listed species.

4. Support river compatible development within the river corridor