CalClim: California Climate Data Archive

CALIFORNIA CLIMATE WATCH
CURRENT ISSUE: January 2006

Read the full newsletter here: PDF format

Preparing for Drought

By Laura Edwards
Western Regional Climate Center

Can it be that seven Western states have created a water use plan for the Lower Colorado River Basin that they all agree on? This news seems to good to be true, but alas, in recent weeks the news has come of a water plan developed by the states of Arizona, California, Colorado, Nevada, New Mexico and Wyoming. The plan, which lays out water allocations during dry times, among other negotiated items, is now awaiting Interior Secretary Gale Norton's signature.

An ultimatum presented years ago by Secretary Norton has driven the formation of this management plan. At the time, the seven states were at a deadlock, in a multi-year drought, and could not resolve issues on how to use Lakes Mead and Powell, particularly during dry times.

In recent weeks, the U.S. Drought Monitor has indicated "D0", or abnormally dry conditions, in southern California. Areas south of Los Angeles, and along the Mexican and Arizona borders, have experienced these dry conditions for several months. Lake Mead (shown in Figure 1), has had low lake levels for at least 3 years, since this photo was taken in spring of 2003, and has been indicated in the U.S. Drought Monitor. For Lake Mead, there are three stages of drought action: 1)anticipation of lake elevation dropping below 1,145 ft puts a Drought Watch in motion; 2) lake level actually dropping below 1,145 ft sets a Drought Alert in effect; and 3) a Drought Emergency is declared when lake level is below 1,125 ft elevation.

Droughts and water management are nothing new to the Golden State. Recent multi-year droughts include: 1912-13, 1918-20, 1923-24, 1929-34, 1947-50, 1959-61, 1976-77 and 1987-92. 1977 stands out as the single driest year on record, which goes back to about 1901. Tree ring studies have shown that past California droughts have lasted centuries.

The Department of Water Resources' "Preparing for California's Next Drought: Changes Since 1987-92" (1), reinforces that one dry year does not in and of itself constitute a drought. A prolonged dry period enduring consecutive years, with accumulating deficits in precipitation and reservoir storage, are signals that a drought is developing. According to DWR (1), a drought is defined by its impact on water users. If there is no demand for the water, how can there be a drought? Oftentimes those who live in rural areas, depend on wells or seasonal precipitation, or are not linked to the state water system are the first to experience drought impacts.

Indicators used to evaluate water conditions on a statewide basis include: snowpack, precipitation, and reservoir storage. On average, about 75% of the annual precipitation in California occurs during the winter season. A few dry winters in the northern Sierra Nevada, where most of California's water originates, can be devastating for millions of users downstream.

In May 2003 Lake Mead provided an example of low reservoir storage. At the time, Lake Mead was at about 2/3 capacity, down 3.1 trillion gallons of water, after a dry period of about 3 years. The water line had lowered 60 feet in that time frame.

The National Drought Policy Commission in 2000 released "Preparing for Drought in the 21st Century". They found that preparing for drought is key to reducing its costs and impacts. In 2004 the National Integrated Drought Information System (NIDIS) was created to distribute drought-related information to user groups, to help them prepare for drought impacts. The groups include farmers, ranchers, businesses, recreational users, and any other group who may be interested. Federal and non-federal agencies are working together to create better tools for all levels of users of the water system nationwide.

The impacts of drought or extended dry periods are varied and far-reaching. Drought emergencies are not immediate, like floods, but come gradually over many months or years. The nation and State of California are trying their best to ensure your safety and reduce the effects of drought, and systems like NIDIS can help you prepare your home and business for the next sustained dry period.

References:
1. Department of Water Resources, July 2000. Preparing for California's Next Drought: Changes Since 1987-92.
2. National Drought Policy Commission, May 2000. Preparing for Drought in the 21st Century.
Other Resources:
1. Western Governors' Association, http://www.westgov.org/index.htm.
2. Department of Water Resources Drought Preparedness, http://watersupplyconditions.water.ca.gov/index.cfm.

Last Updated 7/25/06.

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California Climate Watch Archive All data in the Climate Watch is provisional and subject to change. Please contact us for updated and quality-checked data. *Previous California Climate Watch* Issues 2006 2005 2004 Monthly Weather Summaries** 2006 2005 2004	CALIFORNIA CLIMATE WATCH CURRENT ISSUE: January 2006 Read the full newsletter here: PDF format Preparing for Drought By Laura Edwards Western Regional Climate Center Can it be that seven Western states have created a water use plan for the Lower Colorado River Basin that they all agree on? This news seems to good to be true, but alas, in recent weeks the news has come of a water plan developed by the states of Arizona, California, Colorado, Nevada, New Mexico and Wyoming. The plan, which lays out water allocations during dry times, among other negotiated items, is now awaiting Interior Secretary Gale Norton's signature. An ultimatum presented years ago by Secretary Norton has driven the formation of this management plan. At the time, the seven states were at a deadlock, in a multi-year drought, and could not resolve issues on how to use Lakes Mead and Powell, particularly during dry times. In recent weeks, the U.S. Drought Monitor has indicated "D0", or abnormally dry conditions, in southern California. Areas south of Los Angeles, and along the Mexican and Arizona borders, have experienced these dry conditions for several months. Lake Mead (shown in Figure 1), has had low lake levels for at least 3 years, since this photo was taken in spring of 2003, and has been indicated in the U.S. Drought Monitor. For Lake Mead, there are three stages of drought action: 1)anticipation of lake elevation dropping below 1,145 ft puts a Drought Watch in motion; 2) lake level actually dropping below 1,145 ft sets a Drought Alert in effect; and 3) a Drought Emergency is declared when lake level is below 1,125 ft elevation. Droughts and water management are nothing new to the Golden State. Recent multi-year droughts include: 1912-13, 1918-20, 1923-24, 1929-34, 1947-50, 1959-61, 1976-77 and 1987-92. 1977 stands out as the single driest year on record, which goes back to about 1901. Tree ring studies have shown that past California droughts have lasted centuries. The Department of Water Resources' "Preparing for California's Next Drought: Changes Since 1987-92" (1), reinforces that one dry year does not in and of itself constitute a drought. A prolonged dry period enduring consecutive years, with accumulating deficits in precipitation and reservoir storage, are signals that a drought is developing. According to DWR (1), a drought is defined by its impact on water users. If there is no demand for the water, how can there be a drought? Oftentimes those who live in rural areas, depend on wells or seasonal precipitation, or are not linked to the state water system are the first to experience drought impacts. Indicators used to evaluate water conditions on a statewide basis include: snowpack, precipitation, and reservoir storage. On average, about 75% of the annual precipitation in California occurs during the winter season. A few dry winters in the northern Sierra Nevada, where most of California's water originates, can be devastating for millions of users downstream. In May 2003 Lake Mead provided an example of low reservoir storage. At the time, Lake Mead was at about 2/3 capacity, down 3.1 trillion gallons of water, after a dry period of about 3 years. The water line had lowered 60 feet in that time frame. The National Drought Policy Commission in 2000 released "Preparing for Drought in the 21st Century". They found that preparing for drought is key to reducing its costs and impacts. In 2004 the National Integrated Drought Information System (NIDIS) was created to distribute drought-related information to user groups, to help them prepare for drought impacts. The groups include farmers, ranchers, businesses, recreational users, and any other group who may be interested. Federal and non-federal agencies are working together to create better tools for all levels of users of the water system nationwide. The impacts of drought or extended dry periods are varied and far-reaching. Drought emergencies are not immediate, like floods, but come gradually over many months or years. The nation and State of California are trying their best to ensure your safety and reduce the effects of drought, and systems like NIDIS can help you prepare your home and business for the next sustained dry period. References: 1. Department of Water Resources, July 2000. Preparing for California's Next Drought: Changes Since 1987-92. 2. National Drought Policy Commission, May 2000. Preparing for Drought in the 21st Century. Other Resources: 1. Western Governors' Association, http://www.westgov.org/index.htm. 2. Department of Water Resources Drought Preparedness, http://watersupplyconditions.water.ca.gov/index.cfm. Last Updated 7/25/06.