This hazard map from USGS shows the Grizzly Creek fire burn scar and its affected drainages. Areas in red and dark red represent a high probability of debris flow in a rain event, which can impact water quality. Courtesy map.

The Middle Colorado Watershed Council (MCWC) is a non-profit focused on protecting the Colorado River between the mouth of Glenwood Canyon, at the Garfield-Eagle county line, and De Beque. This 75-mile stretch of river passes through Glenwood Springs, New Castle, Silt, Rifle and Parachute.

Recently, the MCWC was awarded a grant from the Colorado River District to help fund water quality testing related to the impacts of the Grizzly Creek Fire burn scar. This $50,000 grant is matched by resources from the United States Geological Survey (USGS). The USGS will provide real-time data to downstream water users about the quality of water flowing down the Colorado River.

“We were concerned with the consumptive-use side of things,” said MCWC Executive Director Paula Stepp. “Consumptive-use regarding the municipalities on the river corridor. What would [post-fire] changes mean for intake for public water and the agricultural community?” Additionally, Stepp cited habitat management concerns as a motivator for detailed water monitoring.

This grant ensured that four USGS Next Generation Water Observing System continuous water quality testing locations were installed or enhanced between the east end of Glenwood Canyon and the west end of De Beque canyon. The grant also covers discrete sampling at four sites between Grizzly Creek and South Canyon. Timing was critical for the organizations to capture baseline water quality data before spring runoff and any monsoon events began transporting material off the scar and into streams.

Continuous observing systems test water quality as it passes by, in-stream. According to USGS Supervisory Hydrologist Cory A. Williams, “concentrations of suspended sediment, nutrients, dissolved organic carbon and other naturally occurring constituents from a burned landscape can increase in downstream water bodies after wildfires.” The monitoring equipment measures water temperature, specific conductance, dissolved oxygen, pH and turbidity, and sends it to the USGS National Water Information System (NWIS) website.

“People downstream will be able to go into the USGS site and they can get warnings of water changes so that they know if they need to do something to protect their intakes,” Stepp explained. “We need to get this water sampling done so that people downstream are aware of changes and can take precautions to mitigate the impact of what those changes would mean to them.” For example, “If you can shut down your intake for your public water, maybe that will save you money, as opposed to having things get within the system… If it’s a chemical change or if it’s a sediment problem that’s coming into your water, the things that you have to do after-the-fact are going to be more expensive than just shutting down for a short period of time.”

According to Stepp, most of the towns along this section of the river rely on water directly from the Colorado River, though some have multiple sources. MCWC is eager to provide outreach to regional water managers, to make sure they have access to this new data in hopes it protects regional water infrastructure. Anyone can visit the USGS site and set up an NWIS water alert, which will send automated email or text messages when water quality measurements exceed a threshold for selected criteria at a specific location.

Additionally, a discrete testing location was set up this spring by the Lawrence Berkeley National Laboratory (LBL) on Grizzly Creek. According to Geological Scientist Kenneth Hurst Williams, program lead, Environmental Remediation & Water Resources at LBL, this testing site will hopefully serve two purposes. Williams’ team studies how mountain watersheds are affected by disturbances, and the Grizzly Creek fire burn scar provides them a proximal location to their primary field site, the East River watershed near Crested Butte, to study wildfire impacts on water quality and nutrient cycling. Additionally, Williams hopes to compare how different forest types’ watersheds are affected by wildfire. The recent Grizzly Creek Fire, Williams Fork Fire and East Troublesome Fire offer an opportunity to collect water quality data from burned drainages with different forest-types. 

Williams explained, “What’s interesting about those three fires, is they have pretty different mixtures of forest composition. The Williams Fork Fire was overwhelmingly burning in conifer forests. East Troublesome was a mixture of aspen and conifer, and Grizzly Creek, at least at the highest elevations, is overwhelmingly dominated by aspen forests and its lower elevations, pinyon and juniper. And so we’re really interested in doing a cross-site, or cross-fire, comparison to see if forest composition helps control the amount, form, type of nutrients – carbon, nitrogen and metals – that run-off, post fire.”

As of May 5, the USGS had not yet seen unusual data from spring runoff due to the burn scar. Again, Williams: “So far, recent rainfall has decreased water temperatures and specific conductance levels, and has increased turbidity levels, with minor changes to dissolved oxygen and pH. These changes follow the typical ranges and patterns we would expect at this time of year and do not appear to show a strong influence from the wildfire.”