2020 Water CourseIntroduction to Colorado Hydrology

Colorado Mesa University

Ruth Hutchins Powell Water Center

Learning Objectives

1. Define hydrology as a discipline within the lenses of science, engineering, and policy

2. Define and explore watershed properties 3. Contrast weather and climate in Colorado.4. Explore the drivers of hydrology and water

resources in Colorado (Snow and Flow) 5. Discuss how water is distributed across the State6. Discover how climate change may impact our

water supply

What is Hydrology?Study of the distribution and movement of water in physical and biological systems

What is Hydrology?Measurement

What is Hydrology?Science

What is Hydrology?Engineering

What is Hydrology?Dynamic Ecosystems / Hazards

What is a Watershed?

Definition “An area that contributes water to a particular

location on a channel” (Novotny, 2003) “The land area that drains to a common

waterway, such as a stream, lake, estuary, wetland, or ultimately the ocean.” (EPA, 2008)

Image: Tracey Saxby IAN Image Library (ian.umces.edu/imagelibrary)

York River watershed, Virginia

Images by Dan Baker (2005, 2010)

Outlet

Headwaters

Mainstem

What is a Watershed?

Powell’s Vision for the West

Watersheds –Hydrologic Units

11

Major Colorado River Basins

Yampa

Colorado

Gunnison

Dolores – San Juan

Rio GrandeArkansas

South Platte

Major Colorado River Basins

Yampa

Colorado

Gunnison

Dolores – San Juan

Rio GrandeArkansas

South Platte

Continental Divide

Mississippi RiverColorado River

Precipitation

INPUTS

Sublimation

Evapotranspiration

Surface and Subsurface Runoff

OUTPUTS / STORAGE

Infiltration:Soil and GW

SublimationEvapotranspiration

Surface and Subsurface Runoff

NRCS SNOTEL

Water Balance

Input – Output = Change in Storage

• Precipitation

Inputs

• Evapotranspiration• Sublimation• Runoff (stream flow)

Outputs

• Soil Moisture• Groundwater

Storage

Colorado Climate:Precipitation

Runoff Distribution in Colorado80% of Colorado’s water is generated in the Colorado River Basin

Colorado Weather:Extreme Rainfall

inches

https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_map_cont.html

NOAA ATLAS 14

Flood Intensity in Colorado

Data Source: USGS NWIS

Climate vs Weather

WEATHER

Climate vs Weather

Slide from: Gigi Richard

Runoff Distribution in Colorado What do we do when we

don’t have water when and

where we need it?

Trans-basin Diversions

State-wide Consumptive

Use 89%

4%

7%

https://www.colorado.gov/pacific/cowaterplan/plan

Snow and Flow

SNOw TELemetry (SNOTEL) Station

Measuring: Snow Water Equivalent (SWE)

Slide from: Gigi Richard

Doesken and Judson, 1997

Doesken and Judson, 1997

Slide from: Gigi Richard

Doesken and Judson, 1997

Slide from: Gigi Richard

2020 Water Year

2019 2020

Calendar Year

2019 2020

Slide from: Gigi Richard

Snow Water Equivalent

Source: NRCS Interactive Map; https://www.nrcs.usda.gov/wps/portal/wcc/home/quicklinks/imap

Source: NRCS Interactive Map; https://www.nrcs.usda.gov/wps/portal/wcc/home/quicklinks/imap

Source: NRCS Interactive Map; https://www.nrcs.usda.gov/wps/portal/wcc/home/quicklinks/imap

Slide from: Gigi Richard

http://wwa.colorado.edu

Rank of Feb-Mar 2019 precip at SNOTEL sites

Source: NRCS Interactive Map; https://www.nrcs.usda.gov/wps/portal/wcc/home/quicklinks/imap Slide from: Jeff Lukas

http://wwa.colorado.edu

Rank of May 2019 precip at SNOTEL sites

Source: NRCS Interactive Map; https://www.nrcs.usda.gov/wps/portal/wcc/home/quicklinks/imap Slide from: Jeff Lukas

http://wwa.colorado.edu

WY 2019 SWE plot –Lake Powell 104 Group

Source: NOAA CBRFC; https://www.cbrfc.noaa.gov/station/sweplot/snowgroup.php

130% of median peak SWE

Slide from: Jeff Lukas, 2019

http://wwa.colorado.edu

Lees Ferry water-year natural flows: 2019 looking good, but not great

0

5

10

15

20

25

30

1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 2020

2019est.17.5 maf(118% of average)

Slide from: Jeff Lukas, 2019

Mill

ion

Acre

-Fee

t (m

af)

Year

One of the biggest snow year….

What happened to runoff in 2019???

http://wwa.colorado.edu

Upper CO River Basin Oct-May precip vs. Lees Ferry flows, 1900-2019

0

5

10

15

20

25

30

0 5 10 15 20

2019est.

UCRB Oct-May precip, in.

Lees

Fer

ry W

Y na

tura

l flo

w, m

af

2018

R2 = 0.67

Slide from: Jeff Lukas, 2019

http://wwa.colorado.edu

UCRB Oct-May precip, in.

Lees

Fer

ry W

Y na

tura

l flo

w, m

af

0

5

10

15

20

25

30

0 5 10 15 20

2000-2019

1906-1999

Upper CO River Basin Oct-May precip vs. Lees Ferry flows, 1900-2019

Slide from: Jeff Lukas, 2019

http://wwa.colorado.edu

UCRB Oct-May precip, in.

Lees

Fer

ry W

Y na

tura

l flo

w, m

af

0

5

10

15

20

25

30

0 5 10 15 20

2000-2019

1906-1999

Upper CO River Basin Oct-May precip vs. Lees Ferry flows, 1900-2019

Slide from: Jeff Lukas, 2019

Precipitation

2019 Water Year: Inputs

Sublimation

Evapotranspiration

Surface and Subsurface Runoff

Infiltration:Soil and GW

2019 Water Year: Outputs / Storage

Udall and Overpeck (2017)

How does runoff relate to temperature?

Temperature sensitivity is defined as the percent change in annual flow per degree rise in average annual temperature.

Udall and Overpeck (2017)

Udall and Overpeck (2017)

Hot Drought

Record Colorado River flow reductions averaged 19.3% per year during 2000–2014. One-third or more of the decline was likely due to warming

Unabated greenhouse gas emissions will lead to continued substantial warming, translating to twenty-first century flow reductions of 35% or more.

More precipitation can reduce the flow loss, but lack of increase to date and large mega drought threat, reinforce risk of large flow loss

Udall and Overpeck (2017)

Climate Change in CO

Climate Change in Colorado

Climate Change in Colorado:

Projected Temperature

Lukas et al. 2014

Climate Change in Colorado:

Projected Precipitation

Lukas et al. 2014

Summary

Colorado is becoming warmer Total precipitation (annual rain and snow depths)

may not change. Precipitation variability in the Colorado Basin has

increased by 10% since 1980. Individual storms will tend to be ”juicier” in a warmer

climate More warm/dry and warm/wet years.

Warmer summer temperatures will dry out land surface faster. Even if precipitation remains the same, runoff may

reduce due to evaporation and dry soils. Hot Drought

Slide information from: Jeff Lukas

Restore our Headwaters

References

SNOTEL Data

USGS Stream Flow Data

Colorado Water Plan

Doesken, N.J. and Judson A. 1997. The Snow Booklet: A guide to the science, climatology, and measurement of snow in the United States. Colorado Climate Center, Colorado State University. Fort Collins, CO. 92p.

Lukas, J. 2019. Snowpocalypse: A 2019 feast after a 2018 famine. Colorado River District, 2019 Annual Seminar. Grand Junction, CO.

Lukas, J., Barsugli, J., Doesken, N., Rangwala, I., and K. Wolter. 2014. Climate Change in Colorado: A Synthesis to Support Water Resources Management and Adaptation. A report for the Colorado Water Conservation Board by the Western Water Assessment. 114 pp.

Udall, B. and Overpeck, J., 2017. The twenty‐first century Colorado River hot drought and implications for the future. Water Resources Research, 53(3), pp.2404-2418.

THA

NK

YOU

jsholtes@coloradomesa.edu