Post-fire restoration to protect water resources
This new projects is in development and subject to change.
Work in the Colorado Front Range core area leverages more than 2 decades of watershed research and management responses to some of the largest wildfires in Western North America. This work includes the headwaters of the Cache le Poudre watershed, a crucial water source for more than 300,000 Colorado residents. Combining the 2012 High Park and 2020 Cameron Peak fires, more than 60% of the forested portion of the Cache le Poudre has been significantly altered by crown and stand- replacing wildfire during the last decade. In this area, robust involvement of USDA Forest Service forest managers, watershed specialists, and researchers alongside watershed stakeholder groups, water utilities, conservation groups, citizen scientists, and other entities within the Northern Colorado Fireshed provides a unique opportunity to develop, test, and disseminate multi-disciplinary, user-focused, post-fire watershed restoration research. National and international involvement of Core Team scientists in developing and evaluating Burned Area Emergency Response (BAER) approaches provides familiarity with ecosystems and wildfire conditions across the 10 priority areas, as well as field measurement and modelling approaches to assess longer-term watershed recovery and biogeochemical responses to various watershed restoration practices.
Cross-region comparative studies will incorporate existing post-fire monitoring of water quality and recovery in the Southwestern (Region 3) and Pacific Southwestern (Region 5) regions. This includes rapid response research following the Hermit’s Peak and Calf Canyon fires in Summer 2022.
Within each Priority Fireshed we will utilize burned areas to track the short and long- term recovery of watershed processes. Within each wildfire perimeter we will identify 1-3 perennial headwater catchments that have been subject to high intensity fire and display high severity fire effects. Each burned catchment will be paired with a nearby unburned catchment that possesses comparatively similar geology, topography, soils, and pre-burn vegetation. The un-burned catchment will serve as the “control” to assess pre-fire and background conditions. Within each burned and un-burned catchment, a series of monitoring protocols will be implemented to determine the rate and extent of watershed recovery to high severity fire.
Field technicians assessing canopy cover and taking water samples at a stream on the Arapaho Roosevelt National Forest.
Indicators of watershed condition and recovery will be evaluated for their ability to effectively measure the outcomes of restoration efforts. Workshop participants would synthesize information on currently used and candidate indicators and the methods for their deployment, providing recommendations on their potential deployment in a monitoring network in the priority firesheds. Examples include:
- Water quality - measured on a continuous basis using a multiparameter sonde validated by water chemistry analyses of samples acquired by an automated sampler
- Vegetation - measured in monitoring plots and remotely, to assess stand regeneration, estimate biomass and changes in aboveground carbon stocks
- Soil carbon and soil moisture - measured at the plot scale
- Geomorphic and Streamflow - measures of hillslope sediment transport, streambank and channel erosion, large wood recruitment (in-channel) and discharge (at the outlet of headwater catchments) with instrumentation to measure peak flows, channel erosion, and ground cover
Fire-affected sites will be classified according to the areal extent within the fire perimeter with high burn severity. Burn severity will be assessed by a combination of remotely-sensed and ground validated methods. Normalized Burn Ratio is used to identify burned areas and provide a measure of burn severity. It is calculated as a ratio between near infrared and shortwave infrared values in traditional fashion. Normalized Burn Ratio 2 modifies the Normalized Burn Ratio to highlight water sensitivity in vegetation and may be useful in post-fire recovery studies. Normalized Burn Ratio 2 is calculated as a ratio between the shortwave infrared values, substituting the shortwave infrared band for the near infrared band used in Normalized Burn Ratio. Post-fire soil water repellency will be measured in a gridded sample in each catchment using an infiltration method.
This suite of vegetation, geomorphic, and hydrologic measures would provide a comprehensive assessment of watershed recovery over time. Replicating this study design across the 10 Priority Firesheds will provide insight into how wildfire interacts with regional geology, topography, climate, and vegetation type to determine long term fire effects and recovery after disturbance.
This work will help land managers better prioritize, monitor and assess the impacts and cost-effectiveness of watershed restoration treatments. This work aims to provide science to help speed recovery of source water supply areas for nearby municipalities and agriculture and industrial uses and to enhance aquatic ecosystem health and riverine recreation, and other watershed values.
We propose that all measures will occur for at least 10 years following the onset of monitoring and would ideally continue until “recovery” has been fully documented.
Objectives
The proposed research will establish monitoring networks that evaluate the effectiveness of short- and long-term efforts to restore watershed ecosystem processes, including revegetation and hillslope and streambank stabilization practices on post-fire surface water quality and sediment, nutrient and carbon storage. This project will:
- Synthesize the state of science regarding natural post-fire watershed recovery and identify key knowledge gaps
- Evaluate the consequences of current revegetation and hillslope and streambank stabilization practices on post-fire surface water quality and sediment, nutrient and carbon storage
- Develop experimental comparisons of post-fire watershed stream restoration approaches
- Develop prioritization and assessment tools to guide recommendations for post-fire watershed restoration in the western U.S.
Application of Research Results
Vegetation, geomorphic, and hydrologic indicators of watershed response will be developed to provide a comprehensive assessment of watershed recovery over time. Replicating this study design across the 10 Priority Firesheds will provide insight into how wildfire interacts with regional geology, topography, climate, and vegetation type to determine long term fire effects and recovery after disturbance.
This work will help land managers better prioritize, monitor and assess the impacts and cost-effectiveness of watershed restoration treatments. This work aims to provide science to help speed recovery of source water supply areas for nearby municipalities and agriculture and industrial uses and to enhance aquatic ecosystem health and riverine recreation, and other watershed values.