Targeting Post-Wildfire Watershed Restoration at Source Water Protection
Poster
#22
US Forest Service, Rocky Mountain Research Station - Charles Rhoades, Research Biogeochemist; Sandra Ryan, Research Geomorphologist; Frank McCormick, Program Manager; Jan Engert, Assistant Station Director
Colorado State University: Timothy Covino, Stephanie Kampf, USFS Arapaho-Roosevelt NFs: Carl Chambers, Coalition for the Poudre River Watershed: Jen Kovecses, Fort Collins Utilities: Jill Oropeza
CROSSING THE LINE
Hayman Fire 2015 Data
Goose
0.3
May
August
0.2
Unburned
Burned
0.1
0.0
Cabin
0.3
0.2
FIRE & WATER
Fourmile Creek, Hayman Fire
Picnic Rock 2004
Hewlett/
High Park 2012
13 years after the Hayman Fire, nitrate
concentrations are 2- 5 times higher
inside the burn compared to portions
of the streams outside the burn.
Bobcat Gulch 2000
Big Elk 2000
Overland 2003
Four Mile 2010
Black Tiger 1989
Nitrate levels are 5-12 times more than
unburned local streams (0.02 mg L-1)
and well above EPA draft levels for
least-disturbed
streams
in
this
ecoregion (0.01 mg nitrate-N L-1).
High Meadows 2000
Buffalo Creek 1996
Hayman 2002
Stream N (mg N L-1)
b
c
b
0.6
Image Credit: Paula Fornwalt
Hayman Fire 2015 Data
2.5
a
0.4
a
a
0.2
a
a
0.0
ne ate igh
H
No der
o
M
ne ate igh
H
No der
o
M
Spring
Summer
Stream nitrate increases after Front
Range fires and can remain elevated
for more than a decade.
Why worry about Stream Nutrients ?
b
ne ate igh
H
No der
o
M
Fall-Winter
0.2
Unburned
Burned
0.1
0.0
Burnt Pine
0.3
Burned
0.2
0.0
0.3
Unburned
Turkey
Burned
0.2
0.1
Unburned Reference
0.0
Stream Sample Location
(Downstream on Right)
WHAT GOES UP… MAY STAY UP
Waldo Canyon 2012
Human & aquatic health
Water treatment complications
Clean water supply from forestland
Ecosystem Productivity – Forest Growth
Disturbance Indicator / Restoration Target
2.0
#22
-1
Nitrate-N (mg N L )
BACKGROUND
0.8
Wigwam
0.3
Black Forest 2013
This new project aims to advance understanding of upland, riparian and instream nutrient retention and post-fire restoration to enhance clean water
supply from burned Colorado watersheds.
Total N
Nitrate
0.0
0.1
PROJECT OBJECTIVE AND APPROACH
1.0
Nitrate-N (mg N L-1)
0.1
High severity wildfires alter the physical and
biological processes that determine how
watersheds retain and release nutrients and
influence stream water quality. Proximity of
the 2002 Hayman Fire and the 2013 High Park
Fire to Front Range populations brought the
fundamental links between forest conditions,
wildfire and water supply into sharp focus and
highlighted the challenges of source water
protection in watersheds vulnerable to severe
wildfire. For example, water quality changes
following the High Park Fire compromised
water supply to >250,000 homes and
agricultural producers.
Hayman Fire 2015 Data
Burned
Unburned
1.5
1.0
Brush Crk: Little Recovery
No decline in mean nitrate since
2002;~100X >unburned streams
Fourmile Crk: The Road Back
Still ~ 10X > unburned streams
0.0
Brush
Brush
Fourmile
Median
Max
Yrs 1-5
0.99
2.20
2015
0.99
1.46
69%
34%
27%
43%
81%
24%
64%
Lasting nutrient impairment may
relate to immediate post-fire changes
and upland, riparian and channel
locations and their rates of recovery.
Brush Creek
Fourmile Median
Max
0.49
2.35
0.19
0.47
Fourmile Creek
Skin & Hill Gulches, High Park Fire
0.1
log NO3-N = -1.68 + 0.014*X
r ² = 0.82
0
20
40
60
80
100
Extent Burned (%)
The extent and severity of the fire and post-fire vegetation cover
influences stream nutrients
Nitrate-N (mg N L-1)
1
Pre Fire 2001
Post Fire 2015
Pre Fire 2001
Post Fire 2015
0.1
r² = 0.62
0.01
0
20
40
60
80
Riparian Exposure (%)
100
Riparian Condition Classes
Support Acknowledged: We are grateful for financial support from The Cities of Fort
Collins & Greeley, Colorado State University, the Joint Fire Sciences Program and the US
Forest Service, National Fire Plan (2016-2019).
Hill Gulch
High Park Fire
Curve shape characterizes reach
hydrodynamics: velocity, residence
time, transient storage.
We will study small catchments
to examine the effectiveness of
restoring
post-fire
nutrient
retention with upland or riparian
plantings. This will help broaden
thinking about source water
protection
and
watershed
restoration to include ecosystem
resilience, forest recovery and
nutrient retention.
CITIZEN SCIENCE
Hayman Fire 2015 Data
10
Hill Gulch, High Park Fire
RESTORATION TARGETS
1
0.01
Forests and watersheds disturbed by
severe wildfire represent a testbed
to advance knowledge of ecosystem
resilience. The “megafires” of the
past decades underscore limitations
of current understanding about
recovery of water quality and
nutrient retention to pre-fire
conditions.
2015 (13 yr Post-fire)
-1
Stream Nitrate-N (mg N L )
84%
TARGETING SOURCE WATER PROTECTION,
ADVANCING WATERSHED RESTORATION & SCIENCE
0.5
Hayman Fire 2015 Data
79%
The Coalition for the Poudre River Watershed (CPRW) is a nonprofit organization formed in the immediate aftermath of the High
Park Fire. CPRW connects municipal water utilities, land
management agencies, watershed researchers and citizen groups to
identify threats to water supply, prioritize watershed restoration
activities and advance understanding of post-fire watershed
processes.
Monitoring by trained citizen
scientists will expand our
project’s capacity to survey water
quality, aquatic biota, channel
and watershed condition more
extensively and will strengthen
local involvement.
Impacted Reach: fast & slow
transport on rising & falling
limbs, indicate that changes in
channel morphology from postfire erosion and deposition have
altered reach hydrodynamics
and in turn stream retention
capacity and nutrient export.