Reference conditions for restoring an estuary at the mouth of the Colorado River

On Wednsday April 29th at 17:00, Dakota Bellow will defend her master´s thesis in Coastal and Marine Management at the University Centre of the Westfjords. The thesis presentation is open to the public on the University Centre YouTube Channel due current COVID-19 outbreak restrictions in place in Iceland.

The thesis is titled, “Reference conditions for restoring an estuary at the mouth of the Colorado River: Tijuana Estuary and the shelly record at Isla Montague ”

The thesis advisors are Dr. Karl Flessa, Professor of Geoscience at the University of Arizona, US, and Dr. Gregory Dietl, Director of Collections at the Paleontological Research Institution at Cornell University, US. The external reader Dr. Jill Welter, Masters Program Coordinator at the School for International Training, Climate Change and Global Sustainability program.


Restoration of the Colorado River Estuary currently faces three primary challenges: a) the need for increased freshwater input, b) the need for increased river-sea connectivity, and c) the need for comprehensive reference conditions, in order to articulate robust and reasonable restoration goals. While recent efforts have addressed the first two challenges, via the delivery of environmental flows and dredging of channels, reference criteria are still needed. This thesis explores two references, namely past ecological conditions from the estuary itself in the form of the benthic shelly record, and current ecological conditions and management techniques from a similar site, Tijuana Estuary. Review of conservation paleobiological research at Colorado River Estuary indicates that benthic species richness and evenness may decline as brackish conditions return. However, a scoping trip to the estuary revealed hypersaline conditions and a lack of living mollusk species at sampled sites. Restoration experience at Tijuana Estuary emphasizes the importance of maintaining river-sea connectivity, in order to restore estuarine conditions. It is recommended that restoration at Colorado River Estuary adopt an adaptive approach to management, allowing for flexibility while creating opportunity for further research, and emphasize functional goals that account for the dynamism of nature and the pervasive influence of contemporary human contexts.

Dakota Bellow defends her masters thesis on restoring an estuary in the mouth of the Colorado River.