Texas Drought: What is it? Raymond Slade, Jr.,

Certified Professional Hydrologist

Slide show organization

• Introduction • Drought definitions • Drought measures (indices) • Impacts • Drought management • Additional drought information

Drought is merely a hazard—mankind is the disaster

Below is a copy of a letter from a representative of Savoy, Texas in response to a Texas Water Development Board questionnaire requesting how much water did you use in the

previous year and did you use surface or ground water.

Google “Texas flood”…

Introduction

You get Stevie Ray Vaughn playing the song “Texas flood”

Google “drought”…

You might get a TV meteorologist defining drought as an annual rainfall deficit

Father Guido Sarducci Vatican Weatherman, SNL

Historical drought severity documentation

Tree ring data show that many droughts in Texas have lasted 5 years or more.

“We know the value of water when the well runs dry” - Benjamin Franklin

Heat comes with drought

Typical drought cycle

Reality—how we deal with drought

Start here

Drought Definitions • What types of drought exist? meteorologic (lack of precipitation during some time period)

hydrologic (surface water and/or groundwater)

water supply availability (i.e., agriculture, municipal supply)

• When does a drought begin? Usually unknown

• What area does a drought cover? Usually unknown

• When does a drought end? Usually ends with a flood

• How do you evaluate drought severity? Meteorologic drought based on beginning date, a defined area, and an evaluation period.

Other drought measures based on a defined area and usually represent current conditions (snapshot in time) rather than a time period.

The U.S. Geological Survey presents streamflow data http://waterwatch.usgs.gov/new/index.php?r=tx&id=ww_current

Evaluate drought severity:

Streamflow data

Texas Water Development

Board presents reservoir and groundwater

levels

Evaluate drought severity: Reservoir levels and groundwater levels

http://wiid.twdb.state.tx.us/

Recent Tx drought assessment Oct 3, 2011

Previous 6 months

http://www.twdb.state.tx.us/data/DROUGHT/index.asp

Worst drought ever?

Drought measures

Palmer Drought Severity Index (precipitation and temperature)

Texas Jan. 1895 through Sept. 2011

Palmer Drought Severity Index (precipitation and temperature)

This index shows that many droughts worse than the current drought have occurred in Texas during the past 100 years.

Palmer Drought Severity Index

Edwards Plateau Jan. 1895 through Sept. 2011

This index shows that many droughts worse than the current drought have occurred in the Hill Country area during the past 100 years.

Guadalupe River near Spring Branch

Drought impacts

Courtesy of Dr. Richard Earl

Drought losses to Texas farmers and ranchers (crop and livestock)

2006: $4 billion Nov 2010 to Aug 1 2011: record $5.2 billion

Hill Country during extreme drought

However every stream and spring in the area has been dry except San Marcos Springs and Barton Springs

Produces an average of 1.7 billion gallons of water per day

Drought identified water dilemmas Conserve water, export water, limit growth?

Drought management

Texas Water Development Board Draft 2012 Water Plan

Findings:

“If current drought conditions approach the drought of record [a multi-year drought in the 1950s], annual economic losses from not meeting water supply needs could result in a reduction in income of approximately $11.9 billion annually and as much as $115.7 billion annually by 2060, with over a million lost jobs,”

Projected water demand and existing supplies (acre feet per year)

TWDB findings (cont)

TWDB recommendations

• To provide sufficient water through 2060-- 562 supply

projects to meet extra needs during drought • Capital cost to design, construct, implement: $53 billion • Municipal water suppliers need $27 billion in State

financial assistance to implement projects

• 2007 Water Plan identified $17.1 billion needed for Municipal water suppliers

• Lawmakers in 2007, 2009 and 2011 appropriated total of $1.67 billion in bonds. Of that amount, only $100 million was (less than 0.4 %) appropriated in the 2011 session. Drought is merely a hazard—mankind is the disaster

Texas Water Development Board Drought Page

http://www.twdb.state.tx.us/data/DROUGHT/index.asp

• What Drought is and How it is Measured • Drought Conditions • Current Drought Monitoring • Outlook • Historical Data • Mitigating Drought • Drought Related Links

Additional drought information

Drought assessments

The TWDB presents 6 common drought indices at http://www.twdb.state.tx.us/apps/droughtinfo/default.aspx

Maps for each of the indices can be viewed at

http://www.twdb.state.tx.us/apps/droughtinfo/MapView.aspx Historic drought conditions for U.S., States or regions

http://www7.ncdc.noaa.gov/CDO/CDODivisionalSelect.jsp

http://journals.tdl.org/twj/article/view/3665/3348