Collaborative Modeling for Water Supply Controversies in Colorado: Technical Challenges and Lessons Learned

Two cities in Northern Colorado (Fort Collins and Greeley) have partnered with The Nature Conservancy and other organizations to test the use of Shared Vision Planning for the planning and permitting of water supply reservoirs. The cities propose to expand two existing reservoirs on the North Fork of the Cache la Poudre River, and have applied to the US Army Corps of Engineers for Clean Water Act Section 404 (CWA 404) permits. The CWA 404 permitting program has a legacy of controversy, especially for water supply projects in high growth areas. Shared Vision Planning has been proposed as a possible new path to providing needed water supply while minimizing environmental impacts and the controversy they cause. Much of the controversy around these permit decisions is focused on technical questions. The Corps, EPA, permit applicants, and environmental interest groups rarely agree on key technical questions such as growth projections, water use rates, water availability and ecological impacts of the projects. Collaborative modeling is key component of Shared Vision Planning and allows stakeholders in these controversial projects to jointly define how the technical analysis of a project will be done. Stakeholders collaborative use the resulting Shared Vision Models to develop and evaluate plausible alternative solutions. There are number of challenges in developing Shared Vision Models and best practices for this type of collaborative modeling are currently being standardized and documented by an American Society of Civil Engineers (ASCE) committee. And the nature of the Cache la Poudre Shared Vision Planning process brings its own challenges. Planners and modelers must to decide how to integrate SVMs with several legacy models, how to make use of available data for environmental impacts, how to integrate SVMs with data and models used for the EIS, all while addressing key technical issues in a transparent manner. This paper will recount the Shared Vision Modeling experience in the Poudre case, highlighting some of the challenges and lessons learned.