Evaluating the Effects of the High Park Fire on Municipal Water SuppliesJennifer Ford & Eva Hanlon

WR 440, Colorado State University

Methods• Sediment loads were measured to evaluate

hillslope erosion into channels• Sediment ponds were built to settle sediment

for water quality treatment• An emergency warning sonde was

implemented upstream to measure turbidity, temperature and conductivity

• Water quality was measured for TDS, TSS, nutrients, metals, etc.

• Wood and straw mulch was applied to 1800 acres to stabilize slopes

(Oropeza 2013)

Conclusion• A strong effect of fire on water quality is direct

deposition of ash post-fire• Phosphorous associated with ash can make

water unsuitable for consumption as well as increase algal blooms in reservoirs

• Warning sondes are an effective way to mitigate ash entering water intakes for rivers in flashy storm conditions

• Managers are increasingly concerned with wildfires as climate trends are becoming drier and hotter and the wildland urban interface becomes more prominent

• Mitigation techniques such as prescribed burns and thinning may become more common as well as attempting to cut down on the wildland urban interface

Discussion• Select nutrients and metals peaked after the

fire but quickly returned to normal levels• No parameters measured ever exceeded

drinking water standards.• Decreased vegetation was found to decrease

infiltration and increase overland flow, causing an increase in sediment transport.

• Post-fire precipitation events caused spikes in the amount of sediment flushed into water supplies

• Ash was deposited along river banks causing potential future quality problems

(Oropeza, 2013)

ResultsIntroduction• The High Park Fire burned over 87,000 acres

in the summer of 2012 (USFS 2012)• A majority of the burned area was within the

Cache la Poudre River watershed • Fort Collins receives 50% of its water from

the Poudre and 50% from Horsetooth Reservoir (Oropeza 2013)

• Seaman Reservoir was also impacted by the High Park Fire and is an important water source for the City of Greeley (Oropeza 2013)

• The purpose of this study was to evaluate the effects of wildfires on municipal water supplies

ReferencesOropeza, J., Heath, J. 2013. Effects of the 2012 Hewlett and

High Park Wildfires on Water Quality of the Poudre River and Seaman Reservoir. City of Fort Collins.

Shea, M. 2012. Waldo Canyon Fire. Colorado Springs Utilities.Steninger, C. 2013. The Effects of the High Park Fire on

Cache La Poudre Drinking Water. Dept. of Civil and Environmental Engineering. Colorado State University.

USFS, "High Park Fire Emergency Response (BAER) Report." 2012.

USGS, 2012. Wildfire Effects on Source-Water Quality–Lessons from Fourmile Canyon Fire, Colorado, and Implications for Drinking-Water Treatment.

Figure 1 shows the High Park fire burn area northwest of Fort Collins CO. (USGS, 2012)

Figure 2 shows a post-fire hillslope within the Waldo Canyon Fire of 2012 (Shea 2012).

Figure 3 illustrates a kayaker in an ash filled Cache la Poudre River after the High Park Fire. Photo courtesy of

C. Klinzmann.

Figure 4 shows increased phosphorous readings near the City of Fort Collins intake post-fire (Steninger 2013).

Figure 5 is an aerial view of Seaman Reservoir which is located north west of Fort Collins, CO. The algal bloom produced high

concentrations of chlorophyll-a (Oropeza 2013).

Figure 6 (above) shows turbidity (black solid line) and conductivity (red solid line) record from early warning system

sonde located approximately four miles above the Fort Collins water supply intake facility (Oropeza, 2013).

Figure 7 (right) shows stream discharge at 5-minute intervals and its relationship to dissolved organic carbon, nitrates and turbidity. This data came from the 2010 Fourmile Canyon in

Colorado (USGS 2012).