Facing the Realities of Weather, Climate, and Water Resources in the Eastern U.S. in the 21st Century

Main page

Agenda

Registration

Comments

Participant List

Abstracts to Review

Directions &
Suggested Hotels

General Information
on Washington DC

Contact: Jan Wilkerson
202 737-9006 ext. 436

 

Support for this invitation-only forum is made possible by AMS Policy Program underwriters: ITT, Lockheed Martin, Northrop Grumman, Raytheon and SAIC.

 

 

 

 

Abstracts to Review

“Bringing Scientists Out of the Ivory Tower”

Alan Betts, Vermont

In the past year I have given more than forty talks on climate change across Vermont to a very wide range of audiences, including the state legislature, business and professional groups, elementary and high schools, colleges, citizens’ groups, and churches. I also address the public at large with commentaries on Vermont Public Radio and newspaper columns and interviews. The public wants to know and understand climate change, as they realize the future of Vermont is at stake. Without reliable information, they cannot adapt and contribute to the transformation of our society.  They know their government is lying to them, but they have difficulty sorting through the sea of deceit to find credible information. My strategy, which I will outline with illustrative slides, is to explain key climate issues in terms people can grasp and outline the likely future impact on Vermont’s climate and environment. I also present the broad strategy for mitigation and adaptation.

"Climate-Change Impacting Hydrologic Forecasting"

Reggina Cabrera, National Weather Service’s Hydrologic Services Division Chief for Eastern Region

Changes in frequency and perhaps magnitude of floods and droughts are a topic of discussion among the scientific community.  Because precipitation is one, if not the main, forcing for hydrologic responses, we should acknowledge that changes are occurring in the hydrologic environment. The challenge for hydrologic forecasters is not whether climate change is causing extreme events but how extreme events will be addressed from the forecasting perspective.

Hydrologic forecasting has evolved from models developed and implemented to issue short-term, deterministic, water-level forecasts to ensembles addressing uncertainties and long-term flow and water supply forecasts. The challenge for the research community is to provide scientifically sound models that can be deployed operationally in a short period of time (minimize the transition from research to operations). For forecasters, the challenge is to rapidly become familiar with new models and incorporate them into their daily operations.

Besides the challenges posed to hydrologic forecasting, there is also the challenge of how to effectively communicate and disseminate relevant information to the public. The proliferation and effectiveness of the internet has opened a new venue of communication.  To satisfy user’s expectations, the delivery of hydrologic forecasts and products has become more sophisticated by incorporating new graphical displays and meeting the challenges of effectively communicating forecast uncertainties to these users. Climate will continue to change and therefore hydrologic forecasters have to be ready to address the user’s immediate need, trusting that improvements in science and technology will aid in long-term forecasting.

“Making information accessible: how the NE Climate Impacts Assessment informs decision-making”

Melanie Fitzpatrick

The Union of Concerned Scientists (UCS) recently released the Northeast Climate Impacts Assessment (NECIA), a collaboration between UCS and a multi-disciplinary team of more than 50 scientists and economists from across the region.  The report explores future climate change in the Northeast states (from Pennsylvania to Maine) under two scenarios of heat-trapping emissions - one scenario in which emissions continue to grow unabated and one in which steps are taken to transition away from a fossil fuel-intensive economy. This talk provides a background on the process of collaboration, outlines the findings with particular relevance to watershed management, and briefly discusses the outreach efforts and solutions offered to communities in the NE.  The NECIA report summarizes the projected climate impacts on key sectors including agriculture, fisheries, forestry, and winter recreation.  This new research starkly shows that, through the emissions choices we make today, we are shaping tomorrow's climate and the tangible impacts our children and grandchildren will need to contend with. 

“New Tools for Regional Planners and Decision Makers - Water Resource and
Flooding Issues in Western North Carolina”

Jim Fox, Director of Operations for NEMAC (National Environmental Modeling and Analysis Center) at UNC Asheville

Our community is faced with multiple challenges at the current time due to climate change and population growth.  This results in competitive land use issues and a diminishing water resource.  Local decision makers, such as county commissioners and city councilors, are asking questions like: What is the sustainable level of development for our area?  Are there limitations on safe drinking water?  How are we going to handle the large projected population growth in our area over the next 20 years?  Considering these factors, what is the right balance between drought mitigation and flood control?

These are topics that we are all interested in, but we find it difficult to discuss without the proper tools.  We are finding that group decision making is enhanced by using a Decision Theater.  The Decision Theater has three main components: Process, Products and Portal.

The Decision Theater process is supported by several factors: 1) All relevant data is accurate, current and available to the group.  2) Visualizations are created to enable group comprehension of the data and scientific principles and see how it applies to their specific area. 3) Narrative and story telling segments are created to add meaning to the visuals, and finally, 4) a Decision Support system is available to allow the group to collectively increase shared knowledge and reduce uncertainty.

New products and tools are now available to our community.  Using a combination of GIS (Geographic Information System) technology and visualization tools, our policy makers can now interact with all of the data and discuss future scenarios.  All of the stakeholders can work together in one room, with not only the visual tools but also decision support tools available.  In addition, a web portal has been created to support the decision process.  The portal is used not only when the group is meeting but is also available to team members working on their own outside of the meetings.

We will briefly look at specific examples using graphics, movies and interactive technologies: Flood Damage Mitigation, Drought Planning and Future Land Use for the Western North Carolina region around Asheville, NC.  We will look at the technologies and techniques used to create the Decision Theater, education and outreach materials, and the supporting database.

“Too Much, Too Little, Too Late: A Private Sector Response to the Water Availability Conundrum”

John Henz, HDR Engineering, Inc. 

A common economic conundrum, thus far unanswered, is the goal of achieving full employment without inflation. In water availability it is the constant challenge of meeting the three-headed hydra of floods, droughts and timing of precipitation while providing a reliable water supply. A look across the country shows the slowly increasing drought across the southeastern United States balanced by a massive snow pack in the Sierras and a steady stream of Pacific storms threatening spring floods.

Agricultural businesses are already trying to anticipate the impacts of an unusual Pacific La Nina pattern on spring and summer crop planting while the insurance industry is preparing for an abnormal severe weather season and concerns of an active hurricane season. The inter-connective impacts of water on business and continue to grow creating a growing need for reliable response by business and government.

Private sector engineering companies are a primary source of reliable information for many businesses, water supply systems and local and state governments. Private sector hydro-meteorologists have developed a number of innovative applications of federal and original research to identify flood and drought severity prediction, produce early water year runoff volume and timing forecasts and outlooks and enhance reservoir operations. The role for private sector meteorologists is growing as the clients seek a trusted partner in the development and maintenance of water supply.

What might climate change mean for water supply reliability in the Washington DC metropolitan area?

Mark Lorie, Interstate Commission on the Potomac River Basin

A robust and successful program for collaborative water supply planning for the Washington, D.C. metropolitan area has been in place since 1982.  Severe droughts of the 1960s and a pubic controversy over proposed reservoirs on the main stem of the Potomac River led the three major D.C. area utilities to join together and form this cooperative system (known as CO-OP). As part of the CO-OP system, the three utilities jointly operate and manage several reservoirs in order to maximize the collective efficiency and water supply reliability.  Both the original design work and on-going planning are based on the usual assumption that history provides an adequate guide for the future.  Planning models for the CO-OP system use historical hydrologic data to test operational methods.  In addition, these planning models use projections of water demand that are largely based on historical trends.  With increasing knowledge of climate change, it has become clear that the supply side of this equation is going to change: the magnitude, timing, and pattern of rainfall, runoff and streamflow will be different from what is shown in the historical record.  Preliminary findings give us some indication of what these changes might look like for a region like the Potomac River basin, but tremendous uncertainties remain.  In addition, changing weather and economic conditions brought by climate change will surely impact the magnitude, timing, and pattern of demands. We may see increased outdoor irrigation for residential or recreational uses, increased agricultural irrigation, and expanded service areas as smaller communities seek to join the larger CO-OP system.  It is difficult for typical water demand forecasting methods to address these issues.

This talk will explore some of these novel risks facing the D.C. area water supply system because of climate change. Implications of changes to rainfall and streamflow patterns will be discussed, along with the potential impact of changing demand patterns.    The talk will introduce some of the ways that these new challenges will be addressed in a new long-term planning study for the CO-OP system.  Given today’s regulatory and financial constraints, the old model of water supply management—using overly conservative demand projections to justify over-built systems—is no longer tenable.  Instead, flexible and adaptive approaches on both the supply and demand side of the equations are needed to meet the potential challenges of climate change.  Ideas for some of these approaches will be explored.

 

“Drought and Water Shortages - Looking Beyond the Climate Affiliation”   

Bradfield Lyon, IRI, Columbia University

While the non-stationarity of the climate system under climate change raises a host of issues for water managers and planners, an increasing awareness of the non-stationarity of water demand is also emerging as an issue, even in the eastern US as highlighted during recent droughts. Episodic droughts are to be expected in the east even in the absence of climate change but their attendant impacts on water supplies are becoming increasingly skewed by an increase on the demand side for water. As such, water planners and managers can be deceived as to the relative severity of recent droughts (from a climate perspective) and place a disproportionate blame on the climate, not the integrity of the water supply system should water restrictions become necessary to avoid water shortages. The sensitivity of regional water supplies to drought in the eastern US is increasing and water managers and planners need to recalibrate assessments of drought severity as measured by hydrometeorological indicators by placing recent droughts in historical perspective in addition to considering possible changes in future climate. This presentation will attempt to quantify some of these relationships through examination of recent water shortages, mainly in the state of NY.

“Overcoming Communication Pitfalls”

Edward Maibach, Center of Excellence in Climate Change Communication Research, George Mason University

Dr. Maibach will briefly present several simple, practical means of overcoming the pitfalls inherent in expert-driven communication. These include adopting an audience-centric approach to communication planning, determining what information will have the most value to audience members, and packaging information in a manner that is most likely to "stick."

“Planning for Changing Climate in NYC"

David C. Major, Columbia University Earth Institute’s Center for Climate Systems Research

Managing risk by adapting long-lived infrastructure to the effects of climate change must become a regular part of planning for water supply, sewer, wastewater treatment, and other urban infrastructure during this century. The New York City Department of Environmental Protection (NYCDEP), the agency responsible for managing New York City’s (NYC) water supply, sewer, and wastewater treatment systems, developed a climate risk management framework through its Climate Change Task Force, a government-university collaborative effort. Its purpose is to ensure that NYCDEP’s strategic and capital planning take into account the potential risks of climate change—sea level rise, higher temperatures, increases in extreme events, changes in drought and flood frequency and intensity, and changing precipitation patterns—on NYC’s water systems. This approach will enable NYCDEP and other agencies to incorporate adaptations to the risks of climate change into their management, investment, and policy decisions over the long term as a regular part of their planning activities. The framework includes a multi-step Adaptation Assessment procedure. Potential climate change adaptations can be divided into management, infrastructure, and policy categories, and assessed by their relevance in terms of climate change time-frame (immediate, medium, and long term), the capital cycle, costs, and other risks. The approach focuses on the water supply, sewer, and wastewater treatment systems of New York City, but has wide application for other urban areas, especially those in coastal locations.  This presentation describes the NYCDEP effort as well as new advances in methods and government planning for climate change in NYC.

Water Planning and Climate Change:
Actionable Intelligence Yet?

Chris Milly, U.S. Geological Survey

Within a rational planning framework, water planners design major water projects by evaluating tradeoffs of costs, benefits, and risks to life and property. The evaluation is based on anticipated future runoff and streamflow. Generally, planners have invoked the stationarity approximation: they have assumed that hydrologic conditions during the planned lifetime of a project will be similar to those observed in the past. Contemporary anthropogenic climate change arguably makes stationarity untenable. In principle, stationarity-based planning under non-stationarity potentially leads to incorrect assessment of tradeoffs, sub-optimal decisions, and excessive financial and environmental costs (e.g., a reservoir that is too big to ever be filled) and/or insufficient benefits (e.g., levees that are too small to hold back the flood waters).

As the reigning default assumption for planning, stationarity is an easy target for criticism; provision of a practical alternative is not so easy. The leading alternative, use of quantitative climate-change projections from global climate models in conjunction with water planners’ river-basin models, has serious shortcomings of its own. Climate models (1) neglect some terrestrial processes known to influence runoff and streamflow; (2) do not represent precipitation well at the finer resolved time and space scales; (3) do not resolve any processes at the even finer spatial scale of relevance to much of water planning; and (4) disagree among themselves about some changes. Even setting aside the issue of scale mismatch, for which various “downscaling” methods have been proposed, outputs from climate models generally are not directly transferable to river-basin models, and river-basin models commonly use empiricisms whose historical validity might not extrapolate well under climate change.

So climate science is informing water management that stationarity is a flawed assumption, but it has not presented a universally and reliably superior alternative. What is to be done? Is climate-change information of sufficient strength to justify making decisions that differ from those that would be optimal under stationarity? I.e., does climate science provide “actionable intelligence” to water planners?

A conservative approach to planning in the presence of climate change would begin with stationarity as a base and then superpose, with quantitative estimates of uncertainties, those model-projected changes that appear to be qualitatively robust. The current state of science suggests that the following changes could be considered robust: (1) reduction in the fraction of precipitation falling as snow and earlier seasonal melting of snow, with consequent seasonal redistribution of runoff and streamflow; (2) gradual sea-level rise with heightened risk of encroachment of saline water into coastal surface- and ground-water-supply sources; and (3) global redistribution of precipitation and resultant runoff, with regional focal points (“hot spots”) of desiccation and moistening. Even considering the attendant uncertainties, the available information about these changes can significantly affect the cost-benefit-risk tradeoffs of existing and prospective water projects and, therefore, can rationally inform decisions about future courses of action or inaction.

"Risk Assessment for Public Water Supplies: Lessons from the Southeast Drought of 2007-2008"

David Moreau, Water Resources Research Institute

There are many lessons that could be learned (or more appropriately, recalled) from the Southeast drought of 2007-2008.  Among them are needs for:

  • operational plans to go beyond conventional water conservation measures in time of emergencies;
  • more effective incentives for improvements in efficiencies of water use;
  • enhanced risk assessments and risk management, and
  • more effective methods for communicating risk to water managers and the general public.

This presentation will focus on the need for enhanced risk assessments and risk management during droughts.  On one hand, a frequently used risk assessment technique used to guide management of surface water supplies can and may have provided biased estimates to water managers in cities where it was used, leading them to believe that the risk was less than it was.   On the other hand, the failure to rely on risk estimates may have led some cities to invoke advanced stages of conservation strategies that caused unnecessary hardships on customers.  The case of Falls Lake serving Raleigh, North Carolina will be used to show the nature of the bias.

A Structured Process for Incorporating Climate Change Information in Water Resource Management

David Purkey, EID

The El Dorado Irrigation District (EID) is a local water management entity serving the western slope of the Sierra Nevada Mountains in California. While EID once served a largely agricultural and rural customer base, the district is rapidly urbanizing as part of suburban growth around Sacramento. This changes would challenge EID planners and managers in the absence of climate change. As the primary source watershed for EID lies within an elevation band that could potentially experience a dramatic decrease in winter snow accumulation and late spring and early winter snow melt runoff., these challenges are magnified. The Stockholm Environment Institute (SEI) is working with EID to introduce climate change considerations in to these plans. This talk will focus primarily in the development of an updated drought plan to accommodate the shifting demand profile within the district.

“What Urban Planners Want to Know about Climate Change and Water Resources"

Scott Shuford, UNC-Asheville

Urban and rural area planners at the local level will be at the forefront in U.S. efforts to adapt to and mitigate climate change.  Water resources management - from potable water supply and delivery to irrigation to stormwater management and flood control - will be a critical element in their planning programs.  Key challenges for planners in water resources managment include the long time span of the climate change issue, the capital planning and expense involved in adapting to climate change, the economic development implications of both stable and shrinking water supplies, and adjustments to the local government regulatory framework necessitated by climate change.  Levels of certainty, long term projections, and extreme event forecasts are some of the weather and climate data that are essential for planners to have available and to be able to understand in order to plan for and effectively communicate water resources issues to decision-makers and the general public.

“Supplying Water in an Uncertain Future: Including Issues of Water Resources, Wastewater Treatment, and Stormwater Management”

Roland C. Steiner, Washington Suburban Sanitary Commission

Water supply utilities often share additional responsibilities for wastewater treatment and stormwater management; and have to plan for future facilities expansion and renewal involving long lead times.  Designs necessarily depend on meteorologic and hydrologic conditions which are expected to impact the facilities.  While it is not known exactly how future hydro-meteorologic characteristics will be different from those of the present and recent past, there is generally accepted evidence that climate will change.

Changing climate will affect the design of future water supply facilities, and the operation of future and existing facilities.  Each of the usual water resources (rivers, reservoirs and groundwater) will be affected.  Changes in runoff resulting from emerging precipitation patterns will likely alter the quality and availability of river water needed for supply.  The anticipated increase in the variability of rainfall will likely lead to more erosion at higher intensities, and may require (additional) storage to meet needs during periods of reduced precipitation.  The design and operation of reservoirs is critically dependent on patterns of runoff and evaporation: both expected to change as rainfall and temperature do.  Groundwater is an important source of water supply, and it depends on recharge through infiltration of rainwater.  With changes in the characteristics of precipitation will come new patterns in the recharge of groundwater and its usefulness for water supply.

Rainfall and its characteristics have a generally under-appreciated impact on the collection and treatment of wastewater.  Even in separate (sanitary only) systems, rain-induced sewage flow can be significant.  Sewers are designed to handle flows with specific peaking characteristics – increase the peak flows in a collection system … and overflows will result.  The critical design criteria for wastewater treatment plants is typically governed by hydraulic loading (flow).  Increases in flows to plants will likely result in residence times which are insufficient for proper treatment. 

As our built environment becomes more densely constructed, the management of stormwater runoff becomes an increasingly important issue in order to avoid urban flooding.  The sizing and positioning of street inlets for stormwater are designed to accommodate rainfall of known characteristics.  With expected increased variability in precipitation, existing design standards for collection, retention and disposal of stormwater will likely be insufficient.

In order to successfully design and operate water facilities for the future, engineers and operators will need characterizations of precipitation and temperature that are likely to occur during the effective lives of those facilities.  Since those lives are likely to extend well into the anticipated era of changing climate, society would benefit greatly from the best efforts of meteorologists to describe (e.g. ranges and probabilities) of future climate conditions.

Weather and climate in the 21st Century: what do we know?  What don’t we know?

Kevin Trenberth, NCAR

The IPCC AR4 assessment has declared that global warming is “unequivocal” and humans are “very likely” responsible.  A brief review will be given of the changes over the past century, making special note of the exceptional changes over the eastern U.S., where it has become a lot wetter and cloudier, but with not much temperature rise in the Southeast.  These changes, which are most pronounced after the 1970s, are associated with changes in atmospheric circulation across the U.S. linked to changes in El Niño and the Pacific Decadal Oscillation. Without the increased rainfall, conditions would be much hotter and drier, and drought more common.  In 2007, such a change occurred, leaving drought-stricken areas throughout the Southeast in association with La Niña conditions.  The result illustrates the potential for much larger warming in the Southeast than just about anywhere else on the planet.

Further greenhouse-induced warming is projected to occur, leading to increased risk of heat waves and drought.  However, robust changes in extremes of precipitation are also very likely.  This comes about because of increased drying and water holding capacity of the atmosphere as global warming continues, with water vapor amounts increasing at about 7% per degree Celsius over the oceans (where it is wet) and a bit less over land.  The increased moisture feeds all storms and guarantees increased intensity of precipitation (both rain- and snow-fall), but increased dry spells in between. Increased intensity of hurricanes and heavy rains is also likely.  Model projections confirm these aspects, so that water management becomes a major issue of how to save water from times of excess for the increased dry spells in between.

Vulnerability of 21st Century Water Resources
in the Eastern US

Brent Yarnal, Department of Geography and Center for Integrated Regional Assessment The Pennsylvania State University

            The eastern United States is a relatively well-watered region, yet availability of adequate clean water is an ongoing concern because of human pressures on the resource.  This concern will grow in the future from a complex set of interacting stresses, including shifting populations, changing economic structures and patterns, aging infrastructure, increasing regulation, and climate change.  Assessing the vulnerability of 21st century water resources does not require science to predict accurately how these stresses will play out, but it does mean that science needs to identify groups, communities, and regions that are potentially vulnerable to socioeconomic or environmental change.  Recognizing these vulnerable entities makes it possible to develop informed policy.

 

 

 

 

AMS Seal

Meet the Speakers:

Alan Betts

Reggina Cabrera

Melanie Fitzpatrick

Jim Fox

Gerald Galloway

John Henz

Mark Lorie

Bradfield Lyon

David Major

Chris Milly

David Moreau

David Purkey

Scott Shuford

Roland Steiner

Kevin Trenberth

Brent Yarnal

 

AMS LogoUpdated:
 Headquarters: 45 Beacon Street Boston, MA 02108-3693
  DC Office: 1120 G Street, NW, Suite 800 Washington DC, 20005-3826
 amsinfo@ametsoc.org Phone: 617-227-2425 Fax: 617-742-8718
© 2005 American Meteorological Society Privacy Policy and Disclaimer