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Like many cities across the West, Glenwood Springs, Colorado (Glenwood) has been forced to restrict residential water use this summer. But rather than drought, or lack of supply, the restrictions in Glenwood stem from challenges with water treatment caused by wildfire.
Last year, the Grizzly Creek Fire burned more than 30,000 acres of forest lands around Glenwood Springs and the two creeks that provide its principal source of municipal supply. Now, rainfall events within the burn area are causing mudslides and flushing large amounts of sediment into Glenwood’s water treatment works. Given the amount of sediment, Glenwood can treat only so much water for residential use.
Unfortunately, Glenwood’s water quality problem is becoming more and more common across the West. Roughly two-thirds of water supplies in the West originate from forested watersheds. As forest fires have grown in scope, duration and intensity, water treatment managers have increasingly found themselves “overwhelmed by the challenge of treating sedimentation, dissolved organic carbon, and chemicals that were released by fire.”
Many researchers attribute the increase in wildfires to climate change. Simply put, a hotter, drier climate makes forests more vulnerable to fire, and makes fires burn bigger, faster, and more intensely. Last month, July of 2021, was the hottest month ever recorded on earth. The forest fire season is starting earlier and lasting longer each year.
In the 1990s, wildfires burned an average of 3.3 million acres/year. Since 2000, that figure has more than doubled, to 7.0 million acres/year. Last year, in 2020, more than 10.1 million acres burned, with 9.5 million of those acres located in the western states. In Colorado, the three largest wildfires in the State’s history all occurred last year, in 2020.
Wildfires cause a myriad of water quality effects. Active fires flush large amounts of ash, debris, and sediment into local watersheds. This debris and sediment include metals, nutrients, and chemicals that can damage the watershed ecosystem and must be filtered or treated before the water is suitable for municipal use.
In addition, by burning away trees and vegetation that hold soils in place, fires exacerbate erosion. When it rains after a fire, even years after, the sediment loading that occurs during the fire repeats. Glenwood anticipates the water quality effects of the Grizzly Creek Fire to remain for at least another five to seven years.
The unpredictability of wildfires presents an enormous challenge to managing municipal water supplies. As one researcher put it:
If you are a municipal water supply manager, you are most concerned with changes in the magnitude, frequency and timing of extreme water discharge and sediment – what are the highest and lowest amounts of water sediment that flow into a stream after a wildfire – because your treatment plants and your water storage systems may not be built to accommodate them.
Last year, following the Grizzly Creek Fire, Glenwood spent millions of dollars repairing and upgrading its water treatment works in anticipation of increased sediment loading. Despite the water restrictions this summer, those improvements have proven largely successful in allowing the treatment works to continue to function.
Importantly, Glenwood has also been able to make use of an alternative source of water supply – more specifically, storage supply it holds rights to outside of the two creeks contaminated by the fire – in a separate river system. Glenwood relied on this storage water during the fire, when water from the creeks was overloaded with sediment, debris, and fire retardant.
Glenwood’s use of an alternative supply underscores the value to municipalities and other water users of maintaining a “diverse portfolio” of water rights. Redundancy in supplies, from alternative sources and basins, is a legal solution that can help protect water users against the adverse water quality effects of wildfires and other natural disasters.
Preparing for the growing risks that wildfires pose to water quality will require action by municipalities and other water users, as well as scientists, engineers, government officials and policy makers, including:
For many researchers, it is not a question of if but when any given forested watershed will be compromised by wildfire. In addition to the water supply challenges presented by drought, the water quality challenges presented by wildfires will require increased attention, education, research and resources over the coming years and decades to mitigate risks and limit adverse effects to municipal water supplies.
For further information on this topic please contact Daniel McCarl at email@example.com.
Somach Simmons & Dunn provides the information in its Environmental Law & Policy Alerts and on its website for informational purposes only. This general information is not a substitute for legal advice, and users should consult with legal counsel for specific advice. In addition, using this information or sending electronic mail to Somach Simmons & Dunn or its attorneys does not create an attorney-client relationship with Somach Simmons & Dunn.
 https://www.postindependent.com/news/no-outdoor-water-use-in-glenwood-springs-until-monday-after-mudslides-impact-city-water-supply/; https://www.postindependent.com/news/glenwood-springs-water-restrictions-in-place-until-monday-june-28/.
 https://www.epa.gov/sciencematters/wildfires-how-do-they-affect-our-water-supplies (“…65% of fresh water supply in the region originates from forested watersheds, which, depending on conditions, can be highly susceptible to forest fires.).
 https://www.noaa.gov/news/its-official-july-2021-was-earths-hottest-month-on-record (over a period of 142 years).
 https://www.postindependent.com/news/glenwood-springs-gets-8-million-loan-for-water-system-upgrades-following-grizzly-creek-fire/ ; see also https://www.fs.usda.gov/inside-fs/delivering-mission/sustain/legacy-severe-wildfires-stream-water-quality#:~:text=This%20study%20found%20that%2C%2015,healthy%20streams%20in%20this%20area (study found that 15 years after Hayman Fire, affected watersheds still had elevated levels of nitrogen).
 https://www.postindependent.com/news/glenwood-springs-gets-8-million-loan-for-water-system-upgrades-following-grizzly-creek-fire/ ; https://denver.cbslocal.com/2021/04/26/glenwood-springs-water-upgrades-sediment-overload-grizzly-creek-fire/ ; https://coloradosun.com/2020/12/01/glenwood-springs-grizzly-creek-wildfire-restoration-watershed-protection/
 https://e360.yale.edu/features/how-wildfires-are-polluting-rivers-and-threatening-water-supplies (“The biggest issue, according to Emelko, is the dissolved organic carbon that is released by wildfires. When mixed with the chlorine that is used to treat water, it can produce carcinogens that most treatment plant technicians don’t have the expertise to manage.”)Read more news and alerts »