John Muir described the Hetch Hetchy Valley as “one of nature’s rarest and most precious mountain temples”. It also was considered one of the most unique and diverse ecosystems in the world (Muir, 1912). Sculpted by glaciers and the Toulumne River, the nine mile long valley is located in the northwest corner of the Yosemite National Park. Hetch Hetchy is considered to be a twin sister of the infamous Yosemite Valley.
In 1913, the Raker Act was passed by congress which allowed the construction of the O’Shaughnessy dam. Consequently, the dam created a deep, finger-like reservoir. Currently, the reservoir is the least visited site within the National Park. (Philp, 2004). Nevertheless, the Hetch Hetchy Reservoir is an integral part of a complex aqueduct system that consists of multiple reservoirs, transport pipes, hydropower stations, and most importantly, water rights. This system provides a reliably clean source of water and power for millions of resident in the San Francisco Bay area.
For decades heated discussions of politics and environmental ethics concerning Hetch Hetchy have reverberated city halls and city walls throughout the world. Justifying the dam’s removal has been analyzed for years and there exists some persuasive arguments of why it is not only economically feasible and environmentally necessary, but socially approved (Null, 2006). Many people are being informed about the complexities revolving around Hetch Hetchy and their opinions are molded into instruments of action; moreover, the discussion is truly just beginning.
This project intends to be a tool and instrument in the discussion. It develops a master plan, through intensive analysis, for a newly exposed Hetch Hetchy Valley once the O’Shaughnessy Dam is obsolete and breached. The thesis considers the extreme complexities bounded within the historical context of the project and explores, lightly, the analysis involved in justifying the removal of the dam and the support pushing for restoration. It investigates the processes involved in restoring a newly drained reservoir through theoretical approaches as well as through case studies and precedence. It develops appropriate design programming that will highlight the beauty of the historical landscape while offering new and exciting recreational opportunities for all types of visitors; all the while maintaining the integrity of the National Park initiatives and the serenity that should exist within a mountain temple.
Research and Methodology:
A sufficient understanding of the history, geology, ecology, politics, and current conditions of the site is paramount to begin a successful planning process for implementation. The majority of the research is qualitative and relies heavily upon previous case studies and precedents. Due to the lack of sufficient data supporting the theoretical approaches to a drained reservoir valley, case studies like the Condit and Elwha Dam removal projects have been explored fully to measure their successes and failures and how they might be relate to the conditions at Hetch Hetchy.
Other forms of research includes an intensive site analysis of current and historical conditions. Historical data such as maps, quotes, political debates, congressional legislation, and time-lines also elucidated the extreme complexities surrounding Hetch Hetchy. The history of Hetch Hetchy inspired an approach towards its restoration that pays tribute to the unconquerable devotion of activists and supporters of this great cause like John Muir.
Interviews were conducted with the park Superintendent of Public Affairs, Scott Gediman and Mather District Ranger, Jay Shields of the National Park Service. The interviews focused on identifying current issues surrounding Hetch Hetchy (maintenance, likability, transportation, access, revenue gain/loss) and what kind of amenities the National Park Service deems important for future growth and development. Furthermore, identifying the successes and failures of Hetch Hetchy’s “twin”, Yosemite Valley, greatly contributes to the master planning and programming of Hetch Hetchy Valley.
The quantitative data collected were mainly statistics and GIS data. The datasets included information on endangered species, ecological processes, and land cover types and quantities. Statistical analysis also provided data like popularity, past survey results, and percentages of pervious/impervious ground cover that aided in the design process.
Comprehensive analysis investigates the overarching complexities of the project. Subjects of analysis include: geology and soils, topography and bathymetry, hydrology and floodplains, historical and existing vegetation, historical and current wildlife and habitat, and circulation. Considerations for the Sierra Miwok Tribe (they inhabited the site for over six thousand years) are rightfully acknowledged. They have sacred rituals and burial grounds throughout the valley. The exact locations of the sacred lands and burial grounds are unknown. Further outreach with the Miwok Tribe would be crucial to preserve and sanctify these locations. It is estimated that there are at least eleven of these locations spotted along the valley floor. Post-dam assessment must include culturally significant sites.
Along the Hetch Hetchy Valley are locations ideal for viewing a diverse array of natural features. Considering a majority of visitors come to Yosemite for sightseeing and relaxing, identifying those locations of highest sight-seeing value would be paramount. The areas with the greatest ability to see the largest variety of site amenities is considered the most valuable. A sight line analysis studied how elevation, ridge lines, natural features, and proximity might elucidate locations where the areas of greatest importance for site programming and design feature placement would be.
Through an in-depth analysis of the slope, proximity to the river, proximity to natural site amenities, and the floodplain buffer, specific locations for design programming were identified. The most suitable locations would be ground with a slope no greater that 3%. Being close to important features like the Toulumne River for access as well as being in close proximity to the natural site attractions are ideal. Areas that are found closest to many of the site features were given higher value. Areas located nearest the Toulumne river were also given a higher value.
Through various tools like the model builder in ArcGIS, the most suitable areas for development and site intervention were extrapolated. These areas are considered suitable development sites for project programming. Not every one of these locations would need or require development; therefore, further analysis must be taken into consideration for appropriate site planning.
Through my analysis and design interventions, I realized that a new palette of programming tools must be introduced in order to accomplish the project goals and to have far less environmental impact than has its twin valley- Yosemite Valley. I concluded that Low Impact Development (LID) for all built edifices on site will increase site identity and decrease the need for importing materials. I proposed that there should be free mass transit from a neighboring camp to drastically decrease car traffic, pollution, and impervious pavement. Therefore, all site interventions and attractions would only be accessible through pedestrian means like walking and cycling. I developed an intricate path system that would provide many access routes to popular locations and decrease pedestrian traffic and minimize human impact on the sensitive environment.
I designated walk-in only camp site locations to ensure that the Yosemite National Park could accommodate more overnight users and inevitably increase the park's revenue. This also would alleviate overcrowding in Yosemite Valley. I clustered development in certain site specific areas to increase likability, identity, and circulation; however, the clustering was in direct response to programs and activity use. Lastly, I tailored the overall design intervention to certain types of recreation because they would be able to have low impact on the surrounding landscape without distracting other visitors. Recreation activities might include, but are not limited to, white water rafting, zip lining, hang gliding, dam and rock climbing, fishing, swimming, mural art, and hiking.
Through the restoration of the Hetch Hetchy Valley, a new and viable ecosystem can be created for both wildlife and humans to experience. This project might also be used as a tool in the building up of resilient principles for our future and an instrument in the dam decommissioning movement. The “Restore Hetch Hetchy” organization is a sister off-shoot of the Sierra Club that completely focuses on the issues involving Hetch Hetchy. Its purpose is to be a local (to San Francisco) activist group to lobby for Hetch Hetchy as well as start a grassroots campaign to educate the citizens of the Bay Area so that they, through their voting power, may begin the tides of change for Yosemite National Park. Spreck Rosekrans, the Executive Director of Restore Hetch Hetchy, has an influential position in this project and is a committee member. The conclusions and analysis of this project are intended to inspire innovative action and change. As a tool and a resource, the analysis documented may aid the movement and be highlighted in blogs.