climate change and water in the west: drought, wildfires, and flood in colorado
TRANSCRIPT
Water in the West - Too little or too much?Challenges of Drought, Wildfire and Flood in Colorado
November 13, 2013 Webinar
Dr. Brian Ebel, Colorado School of Mines
Sheila Murphy, US Geological Survey
Dr. Jeff Writer, University of Colorado Boulder
Dr. Anne Gold, CIRES & Deb Morrison, University of Colorado Boulderhttps://sites.google.com/site/climatesciencewebinars/water-module/webinar-2-activity
Water in the WestWebinar 2 – Too Little or Too Much?
Please also visit the webinar resources and activities site:
https://sites.google.com/site/climatesciencewebinars/water-
module/webinar-2-activity
Anne Gold Deb Morrison
Webinar Series Facilitators
Water in the West Webinar Series
Overall Structure
• Two webinars
• Background reading material on the website -
https://sites.google.com/site/climatesciencewebinars/water-
module/webinar-2-activity
Requirements For Credit
More Webinar Series to come
• “Extreme Weather” in Spring 2014
Brian Ebel, PhD.
Hydrologist
Colorado School of Mines
Sheila Murphy
Hydrologist
USGS
Organized by:
Anne Gold, Ph.D. CIRES & Deb Morrison, CU Boulder School of
Education
Jeffrey Writer, PhD.
Environmental Engineer
University of Colorado
Too Little or Too Much?Drought, Wildfire and Flooding in Colorado
November 13, 2013
Question for Scientists…..
Can you describe the relevance of
evaluating water from a watershed
perspective?
What is the Boulder Creek watershed?
Mississippi River Watershed
Watershed: the area of land that drains into a water body
From Murphy, 2006
From USGS National land cover data set
Boulder Creek WatershedLand Cover
Placer gold mining on Fourmile Creek, circa 1890
Boulder Creek – Mining and Water
From Murphy, 2006
June
October
Width of blue line represents discharge
From Murphy, 2006
Water Supply in the Boulder Creek Watershed
Question for Scientists…..
Can you elaborate on water quality and
quantity issues stemming from watershed
variability?
Population Growth and Water Usage
From Colorado State Demographic Office
From Colorado River District
Question for Scientists…..
Why do we see increases in wildfires in the
western US?
How do these increases affect watersheds?
Annual frequency of large (>400 ha) western U.S. forest wildfires
(bars) and mean March through August temperature for the western
United States (line).
Westerlinget al. Science 2006
It’s Getting Hot in Here
Average frequency of
western U.S. forest wildfire
by elevation and early, mid-
, and late snowmelt years from 1970 to 2002
Westerlinget al. Science 2006
Earlier Snowmelt Contributes to Wildfires
Hydrologic Impacts of Fire:
Changes in the Ecosystem
Before fire After fire
Before fire After firelitter
organic rich soil
mineral soil
ash
ash/soil
mineral
soil
Transpiration
Interception
Storage
Infiltration
Rates
How Does A Watershed Respond?
22
Flash Floods
Debris Flows
Sediments in Reservoirs
Question for Scientists…..
Using the FourmileCanyon fire as an
example, can you explain impacts of wildfire
on water supply?
2010 Fourmile Canyon Fire, CO
Map of
2,500
hectare
burned area
Image: NASA
Boulder, CO
M. Boulder Cr.
Fourmile Cr.
Gold Run.
Storm Variability in the Fourmile Creek
Watershed, 2011June 19-20Total P 27-34 mmMax I30 10-14 mm/hr
July 7Total P 8-31 mm
Max I30 7-49 mm/hr
July 13Total P 0-33 mmMax I30 0-41 mm/hr
Measured rainfall at UDFCD, USGS, and
NADP gauges interpolated by kriging;
I30: Maximum 30-minute rainfall
Question for Scientists…..
So far we have talked about wildfire and its
effect on hydrology.
What are the implications for water quality,
particularly as it relates to drinking water?
Samples of Fourmile CreekJuly 13-14, 2011
Upstream of burned area
Within burned area
Surface Water Drinking Water
Source water
• Suspended solids
• Dissolved organic carbon (DOC)
• Pathogens
• Etc.
Water treatment• Coagulation/Filtration
• Disinfection
DOC Concentrations (2 Years of Data)
- High DOC
causes water
treatment
problems
- Typically
elevated during
spring runoff
- Remained high
2 years post-fire
during
thunderstorms
2
4
6
8
20406080
Sep O
ctNov
Dec Ja
nFeb M
arApr
May Ju
nJu
lAug
Sep O
ctNov
0
2
4
6
820406080
Drinking water
treatment threshold
Drinking water
treatment threshold
Upstream from burn Downstream from burn
FCCR FCWM
FCLM FCLM FCBC
DO
C (
mg/L
)
Base-flow & Snowmelt
Thunder-
storm
2010-11
2011-12
Effects of Wildfire on Drinking Water Supply
Elevated nutrients eutrophication
Question for Scientists…..
Other disturbances will have an impact on
water quality as well, for example, the recent
Storm of 2013.
Can you talk to us about this?
Indirect
measurements
after the flood
suggest peak
was actually
even higher
(<2,300 cfs);
these data are
being modified
Discharge of Fourmile Creek
Fourmile Creek Below Gold RunSept. 15, 2013
From http://ropeandsummit.wordpress.com/
Fourmile Creek Below Gold RunSept. 15, 2013
From http://ropeandsummit.wordpress.com/
Fourmile Canyon (upstream of burned area)September 19, 2013
Photo by Sheila Murphy, USGS
Showing old
railroad track.
Question for Scientists…..
How would you describe the connection
between the Fourmile Canyon Fire and the
Colorado Storm?
Did the fire have an effect on the flood?
Total Rainfall for September 9 to 17, 2013
(430 mm)
(230 mm)
Interpolated using Urban Drainage & Flood Control District rain gauges.
From NOAA using rainfall data from NOAA,
UDFCD, CoCoRaHS and others
Rainfall Totals for Northern Colorado, with
Watershed Boundaries - September 9-16, 2013
Localized upslope
rainfall event
Question for Scientists…..
How significant was this storm?
Was it a “100-year flood”?
What does that mean?
Floods in Boulder
May, 1874: Boulder Creek
May, 1894: Boulder Creek
July, 1906: Sunshine Canyon
July, 1916: Fourmile Canyon
Aug., 1955: Fourmile Canyon
May, 1969: Boulder Creek Canyon Blvd during flood 1894,
Denver Public Library
9th street
Images from Denver Library
7th street
Floods in Boulder: May 1894
19th street
19th Street flooded from
Canyon to the Hill, 8 feet
deep and a mile wide
100 Year Flood: What’s in a Name?
An
nu
al P
eak
Flo
w
Exceedance Probability1 0
Problem is that there is often little data for extreme events
Question for Scientists…..
What are the implications of variable water
supply on urban planning along the Front
Range as we look toward the future?
Water in the West - Too little or too much?Challenges of Drought, Wildfire and Flood in Colorado
Questions & comments: [email protected]
Video replay: http://www.livestream.com/lmac
Slides: http://www.slideshare.net/learnmoreaboutclimate
Resources: https://sites.google.com/site/climatesciencewebinars/water-module
A live broadcast from University of Colorado Boulder
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Next Webinar Series: Spring 2014 – Extreme Weather