Transcript Interactions with Colorao Municipal Water Managers Elevate

Interactions with Colorado
Municipal Water Managers
Elevate the Use of Climate
Information
Jessica Lowrey and Andrea Ray
NOAA and Univ. of Colorado
Western Water Assessment
Overview
Study group
Dillon Reservoir-Denver Water supply
Methods
Uses of climate information and forecasts
Factors affecting the use of climate
information and forecasts
Interactions with WWA affect this use
Recommendations
Study Group
Northern
Boulder
Westminster
Denver
Aurora
Colorado Springs
Six Front Range water providers: Northern Colorado
Water Conservancy District, Boulder, Westminster,
Denver, Colorado Springs, and Aurora
Serve about 60% of Colorado’s population
Context:
Interactions with WWA and other climate information
providers since 1998
Drought in 2002
Methods: Interactive Model
Researched decision processes and
institutional capacity
Interdisciplinary team at WWA and NOAA
communicating with water managers
Interviews
Workshops and meetings
Results:
Use of climate information & forecasts
Data used in annual and long-term decisions
Instrumental record of hydrology
Current snowpack and streamflows
Streamflow/reservoir inflow forecasts
Graph from NRCS
Use of climate information & forecasts
Probabilistic streamflow forecasts in the form of
exceedence probabilities for precise locations.
GUNNISON RIVER BASIN
Streamf low Forecasts - April 1, 2007
<==== Drier === Future Conditions === Wetter ====>
Forecast Pt
(Forecast Period)
Taylor Park blw Taylor Park Res
(APR-JUL)
90%
(1000AF)
70%
(1000AF)
54
63
50% (Most Prob)
(1000AF)(%AVG.)
70
68
30%
(1000AF)
10%
(1000AF)
77
88
Use of climate information & forecasts
Seasonal climate forecasts are used qualitatively…
Water managers look at and discuss climate forecasts
They use them in mental models, when they are “on the fence”
about drought restrictions
…But they are not in a form that can be
incorporated into models.
Climate forecasts do not provide data on river basin scale
Water managers can’t use temperature and precipitation in
models, only streamflows
Skill/verification information is hard to locate and interpret
Climate forecasts are most often “EC” for precipitation in this
region
Factors affecting use of climate
information & forecasts
Quality of information and forecasts
Institutional capacity
Sensitivity of water supply to climate
variability
Perception of risk
Climate literacy
Institutional capacity
Definition: the ability of a decision-making entity to
incorporate new information into decision
processes.
Higher capacity 
More staff, diverse areas of expertise
More time for learning
Use of sophisticated operational or planning
models
Cities with higher institutional capacity are more
likely to try to use new climate information and
forecasts.
Sensitivity of water supply
to climate variability
Definition: impact of natural climate variability on
water supply.
This region is sensitive due to snowmelt dominated water
supply, population growth, fully appropriated rivers
Higher sensitivity 
Ratio of average storage : annual demand = 1:1
Water rights have junior priority
Water supply comes from only one basin
Anticipating high growth
While these cities had different levels of sensitivity,
they were all impacted by the drought of 2002
(e.g. water use restrictions).
That experience made them realize that their system
may not be reliable if they only plan for droughts
in the historic record.
Annual Flow (1000 acre-feet)
[Undepleted] Annual Flow , South Platte R. at South Platte, CO, 1916-2002
800
700
600
500
400
300
200
100
0
1915
2002
1930
1945
1960
1950’s
1975
1990
Data source: Denver Water
2005
Perception of risk
Drought of 2002 made water managers realize that
their systems were vulnerable to drought.
Single year with lower snowpack and streamflows than
anything water managers had experienced or seen in
the hydrologic record.
This led to a change in perception of risk to climate
variability…
…And a desire to learn more.
After 2002, WWA started to get more information
requests (paleo reconstructions, climate forecasts,
natural variability, climate change)
Climate literacy
As perception of risk increased…
WWA provided education about climate variability, climate
system and climate prediction
…Climate literacy increased.
Water managers are now asking more specific questions
and are considering using additional climate
information.
…this lead to increased use of climate
information and forecasts.
Paleo reconstructions of streamflows in longterm models.
Downscaled GCM projections in hydrology
models.
Climate variables in annual reservoir
projections
Putting it all together:
Perception of higher risk, coupled with higher
sensitivity of water supply to climate variability
increases the desire to use climate information
and forecasts.
A severe drought led to perception of higher
risk, and water managers sought out climate
knowledge from WWA and others.
Climate literacy, plus perception of higher risk,
and institutional capacity enabled these water
managers to seek out and use new climate
information and forecasts.
Sensitivity of water supply
Drought of 2002-2006
Perception of risk
Interactions
with WWA
Climate literacy
Institutional capacity
Use of climate
information
and forecasts
Recommendation 1: Education on
climate system and natural variability
Effect of climate patterns (e.g. ENSO) on
regional weather
Regional trends in temperature, precipitation,
and streamflows; compare anomalous years to
natural variability
Re-occurance interval of single- and multi-year
droughts and other extremes
Regional variability in historic streamflows
among river basins (exceedence probabilities);
reliability of current or future water rights
Recommendation 2: Education on
forecast methodology and skill
Underlying assumptions and uncertainties of
forecast models
Sources of forecast and data error
Verification methods, including hind casting
Types of verification (resolution/sharpness vs.
reliability)
Skill vs. accuracy
Regional patterns of skill
Recommendation 3:
Information
presentation
Tercile precipitation (inches)
Location (climate
division)
lower
middle
upper
W Colorado
precip range
less than 3.38
3.38-4.59
greater than 4.59
% chance
33.3%
33.3%
33.3%
precip range
less than 1.46
1.46-2.80
greater than 2.80
% chance
42.9%
35.3%
21.8%
SW Arizona
Example of streamflow forecast that water managers use:
GUNNISON RIVER BASIN
Streamf low Forecasts - April 1, 2007
<==== Drier === Future Conditions === Wetter ====>
Forecast Pt
(Forecast Period)
Taylor Park blw Taylor Park Res
(APR-JUL)
90%
(1000AF)
70%
(1000AF)
54
63
50% (Most Prob)
(1000AF)(%AVG.)
70
30%
(1000AF)
10%
(1000AF)
77
88
68
Example of climate forecasts presented in a similar manner:
precipitation (inches) in each exceedence category
95% (min)
75%
50% (most prob)
% of
ave
rag
e
1.98
3.07
3.96
100%
4.96
6.6
0.4
0.99
1.66
81%
2.62
4.61
25%
5% (max)
different from
average?
W Colorado
no
SW Arizona
below average
Questions?
Contact us at:
[email protected]
[email protected]
http://wwa.colorado.edu