ABSTRACT: This study assesses the impact of Glen Canyon Dam releases on rafting (white-water boating and day-use rafters) and angling recreationists in Glen Canyon and Grand Canyon National Park using attribute and contingent valuation surveys. Several sources of information were utilized in this study: knowledgeable people (fishing quides, rafting guides, resource managers, and GCES researchers), seven formal surveys (including attribute surveys), and contingent valuation survey to quantify, in dollars, the effects of dam releases on the recreational exoerience. The goal of the study was to assess the impact of alternative annual flow release patterns for Glen Canyon Dam on recreationists in the aggregate. Flow regimes combining high constant flows in the summer months with moderate or low flows during the remainder of the year would be likely to produce the largest recreational benefits. Extreme high or low flows will adversely affect all river recreation, with flows below approximately 5,000 cubic feet per second and above 35,000 cubic feet oer second to both boaters and anglers.
It is apparent that before emplacement of the dam gully degradation in terraces was restored by periodic alluvial deposition from river floods, but perhaps even more important is the redistribution of flood sands onto higher terraces by wind. Thus, we propose the term "restorative base-level hypothesis" to emphasize the dynamic equilibrium between gully erosion and renewed deposition, a process that remains active in Cataract Canyon but is disrupted in Grand Canyon by the presence and operation of the dam.
We developed type geomorphic settings to develop a conceptual process model for the diverse small-catchment geomorphic system in Grand Canyon. Research findings explain how streams are able to cross broad, flat terraces given a rainfall event and how they become progressively more integrated with the river. The primary channelization processes are ponding and overflow, alluvial fan progradation, and infiltration and piping, all of which contribute to nickpoint migration. An understanding of these processes was essential to building the geomorphic model.
The predictive mathematical model quantifies erosional vulnerability by applying a hypothetical rainfall event of 25 mm/hour onto a catchment above a "pristine" terrace sequence. The principal driving factor for erosion is basin area. The principal resisting factor for erosion is terrace diffusion capacity, which is a function of terrace sand cross-sectional area and infiltration capacity. Several important modifying factors are applied to the basic model to determine relative vulnerability of each terrace to gully erosion. Vulnerability of the top terrace at each catchment is plotted against the measured amount of gully erosion in that terrace, providing a base line against which progressive changes in gully depth can be easily monitored in the future.
Field studies and research show that: (1) gully erosion of terraces has been severe during the past 20 years in Grand Canyon due to unusually high precipitation; and (2) sediment deprivation coupled with the lack of large annual floods has caused a reduction in restorative (depositional) factors. Continued measurement and documentation of geomorphic processes in catchments, particularly at type geomorphic settings, will further refine and verify the predictability of the model. We conclude that beach-habitat-building flows are essential for initiating natural restorative processes and that one of the most important processes in gully mitigation may be eolian reworking of newly deposited flood sands onto higher terraces. Prior to the construction of Glen Canyon Dam, gully-deepening and river/wind depositional processes were in dynamic equilibrium, allowing the preservation of ancient cultural sites for the past several thousand years.
The summer after my Junior year, I studied abroad in Denmark and was given the opportunity to create my own research topic. My interest in Sustainability has always revolved around food, so I started thinking about ways that I could incorporate this interest with the geographical backdrop of Århus, Denmark. Food is a medium for so many uniquely human creations: celebrations, art, connection, and taste. Food is also a big driver of climate change, as the meat and agriculture industries account for more than half of all greenhouse gas emissions. However, I wanted to research more than food. I wanted to incorporate balance; a balance of local and global food systems, a balance of individual and community relationships, and a balance of science and art. I wanted to show how food is a driving force in achieving global sustainability and resilience.
After much contemplation, I began researching the connections between local food and community wellbeing in the city. I interviewed farm-to-table chefs, local farmers, farmer’s market vendors, street food vendors, and consumers on their relationships with food. The topic itself was flexible and open-ended enough so that each interviewee could relate it to their lives in a unique way. I loved the research so much that I decided to continue interviewing stakeholders in the Phoenix metropolitan area. Through the continuation of my research in Arizona, I was able to include a comparative element that offered a better perspective on the matter. I found that the history of the country itself has a significant influence on people’s mindsets and actions surrounding food and the environment. The common theme I heard from all interviewees, however, was their confidence in the power of food to unite people to one another and to the natural world.
I chose to create this illustrated book because my research experience was a whole and inseparable experience; it could never be fully expressed in words. I wanted my project to be an intellectual and visual map of my journey, inspiring the reader to go on a journey of their own. Therefore, I partnered with an undergraduate art student at Arizona State University, Sofia Reyes, to help create my vision. I shared my experiences, photos, and stories with her so that she could create the beautiful watercolor paintings that make the book so visually appealing and accessible to all demographics. The images act as a way of engaging all of our human senses, initiating a stronger connection to the material presented.
Creating this project was my favorite experience as an undergraduate, and I feel fortunate to be able to tell the stories of those intimately tied to the local food system. I am in the process of entering my book in various competitions including Writer’s Digest, Reader’s Favorites, The Food Sustainability Media Award, and The Indie Book Awards. I am also going on to publish the book through a small publishing company.