Managing Forests for Healthy Watersheds
Managing Forests for Healthy Watersheds
Healthy and resilient forests support water downstream
Water is essential for life in the West, but it’s also a product of the health of the land surrounding it.
Watersheds connect the land and water, carrying rain and melted snow downhill through streams, rivers and underground pathways. Along the way, water can pick up nutrients, sediments or even pollutants.
Colorado’s mountain watersheds are vital to the nation’s fresh water supply. Water from Colorado serves our residents, but also those in 18 other states. Four major river systems – the Platte, Colorado, Arkansas and Rio Grande – begin in Colorado’s mountains and drain into one-third of the landmass of the lower 48 states.
Most of this water comes from snowmelt, which supplies 75% of the flow in these rivers. Nearly 40% of the water comes from the highest 20% of the land, most of which is in national forests.
Colorado water supports cities, towns, farms, ranches, fisheries and wildlife. In fact, river water is often recycled and reused many times before leaving the state. With a dry climate, frequent droughts and growing demand for water, protecting our water supply is a high priority for the Colorado State Forest Service and our partners.
To help, the CSFS works with Colorado water providers like Denver Water, Colorado Springs Utilities, Northern Water and Aurora Water. Together, we identify and protect vulnerable watersheds by reducing hazardous wildfire fuels and promoting resilient forests.
Lessons from the Upper South Platte
The Upper South Platte Watershed spans 2,600 square miles across eight Colorado counties and supplies water to 2 million people. Since the mid-1990s, six major wildfires have burned in the watershed, severely damaging the area and water quality.
In 1996, the Buffalo Creek Fire caused massive erosion, sending 1 million cubic yards of sediment into Denver Water’s Strontia Springs Reservoir. The fire resulted in ash and dead vegetation that increased runoff and lowered water quality significantly downstream.
The ecological damage from the 2002 Hayman Fire – the largest in state history at the time – continues to affect Strontia Springs today. So far, more than $70 million has been spent to reduce these long-term impacts.
Severe fires threaten forests and water quality
Colorado’s year-round wildfire season puts water quality, public health and the economy at risk.
High severity wildfires burn all vegetation, leaving behind unstable soil that erodes easily. Soil after a severe fire is highly hydrophobic, meaning it repels water instead of absorbing it. Without plant roots to hold the ground together, the loose soil slides downhill, especially on steep slopes (CSFS, 2016).
In 2011, tributaries along the South Platte River showed sediment levels to be four times higher in severely burned areas, which continued for five years post fire (Rhoades, 2011).
Excess sediment can pollute waterways, making water treatment difficult and harming fish and wildlife. Active management can help promote resilient forests that recover faster from wildfire. Fires that occur in a managed forest with less fuel burn less severely, and the watershed is able to rebound more quickly.
Protecting trees and water for the future
As a headwaters state, Colorado’s water management decisions impact water security across the West. Decades of drought, combined with higher demands from population growth, have reduced the amount of water in our rivers and reservoirs. Water shortages are no longer a concern for the future – they are already happening.
Keeping Colorado’s water supply secure requires managing forested watersheds through ongoing collaboration among landowners, contractors and partners at the local, state and federal level.
The Colorado Water Plan provides a framework to meet the state’s water needs and emphasizes shared stewardship. Additionally, the 2020 Colorado Forest Action Plan highlights key watersheds that support agriculture, recreation, ecosystem health and downstream communities.
The CSFS and our partners work to identify and enact cross-boundary projects that benefit communities and the environment. Key partnerships include the Forests to Faucets Program and the Forest and Land Managment Services Agreement, both with Denver Water.
To prepare for a changing climate, land and forest managers use flexible strategies that consider multiple climate scenarios. This includes planting drought-tolerant vegetation and prioritizing restoration efforts.
Reforestation also plays a key role in keeping forests healthy and resilient. The CSFS nursery grows and distributes seedling trees and shrubs to support conservation efforts. These trees help reforest burned areas, improve wildlife habitat and reduce soil erosion after floods.
The choices we make today will shape the future of Colorado’s forests and water supply. Careful management is essential to ensure that future generations benefit from healthy forests, clean water and resilient landscapes.
References
Colorado State Forest Service. 2016 Report on the Health of Colorado’s Forests.
Rhoades, C. C., Entwistle, D., & Butler, D. (2011). The influence of wildfire extent and severity on streamwater chemistry, sediment and temperature following the Hayman Fire, Colorado. International Journal of Wildland Fire, 20(3), 430. https://doi.org/10.1071/WF09086