Colorado’s Front Range is no stranger to the dramatic interplay of fire and floods. Over the past five years, the region has seen several destructive forest fires with huge economic losses such as Waldo Canyon ($453.7 million), Black Forest ($292.8 million), Fourmile Canyon ($217 million), and High Park ($113.7 million). In the wake of these fires often comes intense flooding as heavy rains hit the exposed, ash-covered soils. Water utilities that draw water from the affected watersheds then face the cost of filtering water laden with ash and silt, repairing flood damage, and switching to alternate waters supplies until watersheds could recover. Near Denver, the combined effects of the Buffalo Creek and Hayman and fires led Denver Water to spend over $30 dredging its drinking water reservoir.
To prevent such disasters from occurring more frequently in the future, conservationists, land managers, and public utilities downstream are investigating the feasibility of investing in large-scale watershed restoration projects so that when and if new big fires occur, they will burn with less severity, enhancing ecosystems that depend on fire but minimizing water related costs downstream. But are such investments economically feasible?
To answer this question, CSE teamed up with the Center for Collaborative Conservation at Colorado State University and World Resources Institute to conduct a preliminary green-gray analysis of watershed restoration options in the Cache la Poudre and Big Thompson watersheds. The analysis was divided into two parts corresponding to the upper and lower portions of each watershed. In the upper watershed, we compared the financial risks associated with a large scale burn similar to the High Park Fire in 2012 (gray) with the costs of implementing an ambitious portfolio of watershed restoration activities designed to reduce the impact of fires (green) including ecologically based thinning, closure and restoration of unnecessary roads, and prescribed fires.
While there are great uncertainties involved in this preliminary, Phase I analysis, we found the potential for cost savings in the order of $320 million over 20 years if the green infrastructure scenario were implemented. We are now working with CCC to find funding to support the full-blown Phase II analysis, which will rely on much more fine-tuned models to predict the consequences of the green infrastructure options we considered as well as the potential costs of future fires.
In the lower watershed areas, we conducted a separate green vs. gray analysis, but our focus was not on fire but potential cost savings to wastewater treatment plants of investing in green infrastructure measures as a least cost way to comply with new water quality regulations for nutrient pollution. Look for a summary of that analysis in a future post on this site.
For our report and related materials, please click here to visit the project page.