2002 Drought Summit
311 Cannon House Office Building
Washington, D.C. 20515
Robert M. Hirsch
U.S. Geological Survey
Associate Director for Water
October 3, 2002
I would like to make a few remarks about the role that hydrologic science can play in helping citizens and communities prepare for and cope with drought. I will confine my remarks to hydrologic or water supply drought, in contrast to agricultural drought. Hydrologic and water supply drought refers to the shortage of water available for withdrawal for uses including: residential, municipal, agricultural, or industrial supply. It also includes the decline in flows of springs and streams that are detrimental to: hydropower production, navigation, recreation, or maintenance of habitat for aquatic and riparian species.
First, we must recognize that droughts are natural phenomena. Their severity and duration cannot be accurately predicted, although our colleagues in the atmospheric science community are making some progress on improving the ability to predict when they may occur. Second, we must recognize that severe droughts will happen again. Human activities (affecting the atmosphere or landscape) may change the pattern of severity and duration of droughts and yet, even in the absence of scientific results that would indicate what kind of changes may take place in the future, society must learn to expect the unexpected when it comes to drought. The paleo-climate record demonstrates previous drought episodes that were either longer or more severe than any we have experienced in the few centuries of our Nation’s recorded history.
The drought that is taking place at this time is a significant one, especially in the Mid-Atlantic States and parts of the Great Plains and Rocky Mountains. For some of these areas the situation today is a continuation of generally dry conditions that have taken place for three to four years. Many of our monitoring locations have shown water levels or streamflows that are below all-time record lows for specific days of the year. However, on an overall basis we believe we are seeing a very significant drought but probably not the “drought of the century” over any large area.
Hydrologic science helps in two ways. The first is in drought planning. The key to success in coping with water supply drought is to assure that water can be drawn from storage to supply water users with an adequate supply when the lack of precipitation limits the natural flow of rivers. This storage can include: surface-water reservoirs or aquifers. This includes traditional forms of ground-water resource development as well as systems of artificial recharge or aquifer storage and recovery that take advantage of excess water during wet periods or of waste water and put it into the subsurface, to be extracted in times of the greatest need. What hydrology brings to planning is the knowledge of the rivers, the range of variations in flow, and the reliable yield of reservoirs and aquifers. This kind of information is most useful when it is organized through the use of mathematical simulation models that can test the consequences to water users and ecosystems of plausible future drought scenarios. State and local agencies and private individuals who must plan for future drought use this information to evaluate their options. USGS historical data on streamflow, now over 100 years long and available on the Internet, are the basis for all of these kinds of analyses.
This kind of drought planning requires a strong foundation of information. About a year ago the House Appropriations Committee expressed to us their concern over the “future of water availability for the Nation . . . for growing communities, agriculture, energy production, and critical ecosystems.” They noted that a nationwide assessment of water availability is several decades old. They asked the USGS to “ . . .prepare a report describing the scope and magnitude of the efforts needed to provide periodic assessments of the status and trends in the availability and use of freshwater resources.” That report has been delivered to the Congress and we would be pleased to discuss the ideas that are proposed in it. Understanding the availability of water for the Nation is really synonymous with understanding drought, for it is in times of drought that our society comes face-to-face with the real limits of the available supply.
The second way that hydrologic science helps society cope with drought is the information that can be used to help communities make the best day-to-day management decisions while the drought is taking place. What kind of water management decisions are possible once the drought has begun? Some of the key decisions are these: holding water in reservoirs to meet potentially more serious needs that may be weeks or months in the future versus withdrawing or releasing it now to satisfy legitimate immediate needs; increasing ground-water pumping to augment surface-water supplies; purchase of water from neighboring jurisdictions or users where this is feasible from an engineering and legal standpoint; and restricting certain categories of water use. Decision-makers need accurate and timely information on the current status and recent trends in streamflow, ground-water level, and water use.
The USGS provides broad coverage for streamflow information through our new Internet system known as WaterWatch (http://water.usgs.gov/waterwatch) that you see on the briefing board beside me. Development of real time ground-water information is only beginning to be implemented but shows great potential. The State of Pennsylvania has worked with the USGS for more than a decade to develop a system they now routinely use in State drought management applications (see http://pa.water.usgs.gov/monitor/).
In the area of water use, the information available for managers concerned with either short-term or long-term decisions is less developed. The National Research Council issued a report this year regarding water use information. That report is entitled “Estimating Water Use in the United States: A new paradigm for the National Water-Use Information Program.” Managers also need good probabilistic forecasts of hydrologic conditions for the coming weeks and months. Our colleagues at the National Weather Service are moving forward with their Advanced Hydrologic Prediction Services, to provide just this kind of information to water managers.
The USGS is very active across the Nation, working with State, local and tribal governments to help them plan for drought and to function effectively during drought. We do this principally through the Cooperative Water Program. In this program, we collect and disseminate data on rivers and ground water, map and model aquifer units, and help to define the water resource and predict how it will behave under the stress of drought. A large number of the 1300 cooperating non-federal agencies with whom we work in the Cooperative Water Program seek our help in better defining the availability of water and the consequences of drought. By using our national network of monitoring sites, scientific staff, and historic and real-time databases, we are able to make valuable contributions to help them in their mission of managing water resources in the face of drought.
As I conclude my remarks, let me compliment the Congress for holding this session, and particularly express my appreciation to Congresswoman Barbara Cubin. We were very pleased to see in a prominent position on her home page the words “Click Here for the latest information on Wyoming Drought Conditions.” Clicking there takes one directly to the USGS Wyoming Drought Conditions page. Providing information for drought planning and for coping with drought are important parts of our mission at the USGS. We are pleased to be able to provide that service to the American people and are pleased to be recognized for doing so. We look forward to continuing and improving these services in years to come.
I will be pleased to address any questions you may have.