Transcript Climate, Drought, and Wildfire Effects on Water Quality

Climate, Drought, and
Wildfire Effects on
Water Quality
Recent Conditions and ShortTerm Forecast
http://www.ispe.arizona.edu/climas/forecasts/oct2005figs/01_temp_cond.html
http://www.ispe.arizona.edu/climas/forecasts/oct2005figs/02_prec_cond.html
http://www.ispe.arizona.edu/climas/forecasts/oct2005figs/03_drought_monitor.html
http://www.ispe.arizona.edu/climas/forecasts/oct2005figs/05_az_resvr.html
http://www.ispe.arizona.edu/climas/forecasts/oct2005figs/08_temp_outlook.html
http://www.ispe.arizona.edu/climas/forecasts/oct2005figs/9_prec_outlook.html
http://www.ispe.arizona.edu/climas/forecasts/oct2005figs/12_enso_outlook.html
http://www.ispe.arizona.edu/climas/forecasts/oct2005figs/12_enso_outlook.html
Historical Drought in the
Southwest
 Palmer Drought Severity index
 Soil moisture availability
 Incorporates
Precipitation, most important
 Temperature
 Soil conditions
 Includes time lags
 If it’s been dry for months, a single rainstorm will
not change drought to wet
 Negative PDSI = dry, positive PDSI = wet

Pacific Decadal Oscillation
 Regular pattern of high and low pressure systems
over the northern portions of the Pacific Ocean.
 20- to 30-year time scale, and correlates with
relatively wetter or drier periods in the western
portion of North America.
 Positive PDO phases tends to enhance El Niño
conditions and weaken the effects of La Niñas.
 Negative PDO phases enhance the effects of La
Niñas and weaken the effects of El Niños
PDO Phase
North Pacific Sea
Surface Pressure
North Pacific Sea
Surface
Temperature
Influence on El
Niño Conditions
Influence on La
Niña Conditions
Positive
Low
Cold
Enhance
Weaken
Negative
High
Warm
Weaken
Enhance
http://www.ispe.arizona.edu/climas
Less Snow, Less Water: Climate
Disruption in the West.
Rocky Mountain Climate Organization, 2005
“What this work shows is that, even with a
conservative climate model, current demands on
water resources in many parts of the West will not
be met under plausible future climate conditions –
much less the demands of a larger population and
a larger economy”
Dr. Tim Burnett, “The Effect of Climate Change on Water
Resources in the West: Introduction and Overview”
Likely Effects of Climate
Disruption in the West
 More Heat

Likely to be greater in winter than summer
 Smaller Snowpacks

Winter precipitation may be more likely in the future to fall as rain
rather than snow.
 Earlier Snowmelt

Warming earlier in the year may melt snowpacks sooner
 Increased evaporation

Increased soil dryness and evaporation from rivers and reservoirs
It’s Not Just the Drought, it’s
the Heat
Snowpack Losses in the
Colorado River Basin
 Predicted losses of 24% by 2010-2039.
 Up to 30% by 2040-2069.
 Snowpack has been below average for 11
of the last 16 years.
What About Last Winters
Precipitation?
 Brought a slight reprieve from sustained drought
conditions in water year 2005.
 Shortage risk has been “rolled back” by about one year.
 System reservoir storage is currently about what it was
in 2003.
 The entire Colorado River storage system decreased
from 55.7 (95% capacity) to 29.7 (52% capacity) MAF
from October 1, 1999 to October 1, 2004.
In Light of All This…
The sky is not falling.
Climate is highly variable with the only
constant being variability.
Evidence of drought and climate change
are likely occurring at a faster-thananticipated rate.
This puts added importance on
cohesive, comprehensive, and proactive planning by water resource
management agencies to ensure
adequate water supplies for the
foreseeable future.
Effect of Climate and Drought
on Wildland Fires
 We initiated this project prior to the Rodeo-
Chedeski fire in 2002.
 We were the ones to mention, and predict,
long-term impacts to downstream reservoirs.
 Most of these predictions have proven to be
true and the reservoirs still suffer from this “resetting” event.
Pre- and Post-fire Nutrient Loading
Oneway Analysis of Total P (mg/L) By Year
35
35
30
30
25
25
Total P (mg/L)
Total N (mg/L)
Oneway Analysis of Total N (mg/L) By Year
20
15
20
15
10
10
5
5
0
0
1998-2001
2002-2004
1998-2001
2002-2004
Year
Missing Row s
Year
15
Missing Row s
Oneway Anova
Oneway Anova
Summary of Fit
Summary of Fit
Rsquare
Adj Rsquare
Root Mean Square Error
Mean of Response
Observations (or Sum Wgts)
0.44874
0.440512
5.617329
5.27942
69
Rsquare
Adj Rsquare
Root Mean Square Error
Mean of Response
Observations (or Sum Wgts)
Analysis of Variance
Source
Year
Error
C. Total
DF
1
67
68
Sum of Squares
1720.9701
2114.1441
3835.1142
Number
34
35
Mean
0.2124
10.2017
0.688917
0.684274
5.838316
8.924348
69
Analysis of Variance
Mean Square
1720.97
31.55
F Ratio
54.5398
Prob > F
<.0001
Means for Oneway Anova
Level
1998-2001
2002-2004
15
Source
Year
Error
C. Total
DF
1
67
68
Sum of Squares
5057.5511
2283.7576
7341.3087
Mean Square
5057.55
34.09
F Ratio
148.3765
Prob > F
<.0001
Means for Oneway Anova
Std Error
0.96336
0.94950
Low er 95%
-1.711
8.307
Std Error uses a pooled estimate of error variance
Upper 95%
2.135
12.097
Level
1998-2001
2002-2004
Number
34
35
Mean
0.2379
17.3626
Std Error
1.0013
0.9869
Low er 95%
-1.76
15.39
Std Error uses a pooled estimate of error variance
Upper 95%
2.236
19.332
Increasing Hypolimnetic Anoxia in Roosevelt
Oneway Analysis of DO_mg_per_L By Sampling_Period
0.6
0.5
DO_mg_per_L
0.4
0.3
0.2
0.1
0
Summer 02
Summer 03
Summer 04
Sampling_Period
Oneway Anova
Summary of Fit
Rsquare
Adj Rsquare
Root Mean Square Error
Mean of Response
Observations (or Sum Wgts)
0.767716
0.758782
0.056288
0.189455
55
Analysis of Variance
Source
DF Sum of Squares
Sampling_Period
Error
C. Total
2
52
54
Mean Square
F Ratio
Prob > F
0.272264
0.003168
85.9318
<.0001
0.54452819
0.16475544
0.70928364
Means for Oneway Anova
Level
Summer 02
Summer 03
Summer 04
Number
Mean Std Error
13 0.356923
27 0.167407
15 0.084000
Low er 95%
Upper 95%
0.32560
0.14567
0.05484
0.38825
0.18914
0.11316
0.01561
0.01083
0.01453
Std Error uses a pooled estimate of error variance
All Pairs
Tukey-Kramer
0.05
Heat and Drought Effects on
Vegetation
Not All Wildfires are Created
Equal…
 The amount of suspended sediment delivered
to a river or reservoir following a wildfire
depends upon several factors including local
topography and vegetation type.
 Some vegetation types have adapted to wildfire
and require it as part of its natural succession.
 Others, such as the Sonoran Desert, have likely
never experienced wildfires like we have seen
the last few years.
Cave Creek Complex and
Rodeo-Chedeski Fires
 Different type and amount of fuel consumed.
 Rodeo-Chedeski: Huge amount of ground fuel
built up for decades.

Intense, high heat fires volatilize nutrients and
destroy roots, tubers, and rhizomes beneath the
surface. Re-vegetation will take years – decades
even with intense re-seeding efforts.
 Cave Creek Complex: Oak, chaparral, brushes
and grassland vegetation have evolved with
frequent fire and require it for succession.
Wildfire and Invasive, NonNative Plant Species
 The Cave Creek Complex Fire started in the
Sonoran Desert.
 The Sonoran Desert never saw fire until the
1970’s when invasive plants began filling in
spaces between native species.
 Cave Creek Complex Fire was carried by red
brome and started in an area that had previously
burned the year before!
 Native desert plants have no adaptation to
wildfire.
 Native plants, even when a wet winter increases
their numbers many fold, lack the biomass of
invading, non-native species and rarely burn.
 The spread of non-native, invasive plant species
is exacerbated by increasing drought, warm
winters, and increasing heat and climate change.
 Increased frequency of fire in the Sonoran
Desert, kills native species and non-natives are
quick to fill this niche.
 The Sonoran Desert will likely look very
different in a few decades and more closely
resemble a savannah.
Watershed and Water Quality
Implications
 From a water quality standpoint, the real danger
lies in having fires start with increased frequency
at lower elevations and then spreading into higher
elevations consuming more biomass and
increasing in intensity.
 Watershed vegetation is the “sponge” that keeps
water flowing in streams and rivers and,
eventually, flowing into reservoirs.
Summary
 There will likely be changes in both water quantity
and quality delivered to the Valley in the future.
 The best way to ensure we have the tools
needed to document these changes is through
continued data acquisition.
 Climate change and drought are linked to
biological, physical, and chemical factors which
directly affect water quantity and quality delivered
to the Valley.
Questions?