In the summer of 1993, the upper Mississippi River basin suffered its worst floods in more than 100 years. The nation watched in awe - then rallied to help - as this act of God turned to human tragedy. Homes, farms, whole towns disappeared under the deluge. Thirty-eight people died and damages reached nearly $16 billion.
      The Great Midwest Flood of 1993 entered the record books as the largest and most destructive hydrometeorological event in modern times. It set records for amounts of precipitation, upland runoffs, river levels, flood duration, area of flooding and economic loss.
      Perhaps the most significant element of this flood was its duration. With rainfall volumes as high as three to four times normal for more than a year, the peak flow-rates for the upper Mississippi River and many of its tributaries stayed at flood level for as long as five months in some areas.
      As part of its natural disaster funding, the federal government formed an multi-agency task force to study the conditions of floodplain management in the region, and make recommendations for preparing for future floods.
      The multi-department, cross-discipline Interagency Floodplain Management Task Force (IFMTF) was formed in January 1994 to study and identify the major causes and consequences of the flooding; to evaluate the performance of existing floodplain management programs; and to make recommendations on changes in current policy, programs and activities of the federal government that would help reduce risk, improve economic efficiency and enhance the environmental condition of the floodplains in the area.
      With some 32 members from 12 federal agencies, the committee began a painstaking process of collecting the necessary information to make sense of the disaster, what causes a flood of such immense proportions and how 50 years of floodplain management stood up to this 100-year flood.

The Task Force's Conclusion:
• Although there is clear evidence that federal, state and local flood damage reduction efforts did prevent billions of dollars in damage, the midwest floods proved that people and property remain at risk despite 50 years of floodplain management activity.
• The ecosystems of the upper Mississippi region are fragile and, given the loss of natural habitat over the last two centuries, the nations now faces severe ecological consequences.
• The division of responsibility for floodplain management between federal, state and local governments is not clearly defined and a more consistent, collaborative floodplain management effort should be pursued.
      But these benign, almost innocuous conclusions are clear understatements when set against the context of the worst flooding in the nation's history.

Understanding a Natural Catastrophe
"Perhaps the most important thing we learned is that we must treat the whole river as a system, instead of a series of independent projects and activities," explained John A. Kelmelis, Ph.D., chief of the science and applications branch of the USGS and director of the Scientific Assessment and Strategy Team (a sub-group of the task force) which prepared the floodplain management report.
      "It's not enough to know that a particular land treatment works for a certain area." He continued, "We must ask if this is the best treatment and how it will affect other areas."
      For example, Kelmelis cites levees that consistently break. "Our research showed that there are reasons these levees consistently break and that these are predictable problems.
      But compiling the information necessary to form a unified, collaborative approach to floodplain management is easier suggested than accomplished - particularly for an area like the upper Mississippi River Basin, which covers some 714,000 square miles in 13 states; 23 percent of the total area in the 48 contiguous Unites States.
      With approximately 20 federal agencies, 13 state governments and hundreds of regional, county, and local government entities, merely compiling a meaningful database is a daunting task, let alone establishing a strategy and unified course for future development.
      Moreover, while the SAST is charged with establishing a data management program, monitoring program and strategic approach for floodplain management, its charter is limited and the team is to be dismantled at the end of the year. They may get the ball rolling, but it will be up to others to keep it in play.
      Who in the vast bureaucratic infrastructure will lead the effort is as yet undetermined. Kelmelis said the federal government is developing an implementation plan to address the recommendations of the report. He expects the plan will be presented to the White House sometime this spring.
      For the SAST, with less than a year to go, what and how are the most pressing questions.

Information as Strategy
"In an information-based society, both spatial and aspatial data are critical to decision-making," the team's report reads. It's three-part information management strategy will serve as the foundation for its overall approach for enabling governing officials to establish and carry out effective policy in the management of the floodplains into the next century. The three part strategy includes:
1. Mapping. Creating a comprehensive baseline data set for the upper Mississippi River Basin.
2. Monitoring and Analysis. Establishing an effective means for monitoring and recording changes in the natural, structural and socio-economic conditions of the basin, as well as all future disasters.
3. Modeling. Developing ecologic, hydrologic and socio-economic models of the river basin and floodways to anticipate major flood hazard areas and develop mitigation and contingency plans for those areas.

Creating a Base Map
The SAST is focusing a great deal of effort this year to developing a prototype baseline geographic information system (GIS) to support a comprehensive, technology-based approach to planning and emergency preparedness. The 240-gigabyte database contains Landsat Thematic Mapper images as a raster basemap, enhanced in critical areas with satellite imagery and aerial photography. Vector-based map layers will be added for dozens of data sets from geomorphology to water tables, to upland runoffs, to man-made structures, to climatological characteristics.
      The effort began with compiling the information to do its analysis of the flood in the first place, and many obstacles presented themselves.
      For starters, the sheer volume and diversity of information was staggering. Information was or is being collected on climatology, geology, biology, infrastructure, private and public land ownership, business activities and economic and social impacts.
      Not only did the area under consideration cover more than 23 percent of the continental U.S., the depth and multiplicity of contributing factors made data gathering a monumental effort.
      "The integrated team approach chosen by the task force proved to be valuable in data collection, once we understood each others languages," Kelmelis said. "We found a number of benefits by sharing data of different types."
      Kelmelis explained that, with geomorphologists, geologists, meteorologists, biologists, engineers and others working together, they were able to improve the quality of the data they used for their evaluation. This experience, he emphasized, will be valuable in developing and using an on-going database of the area.
      Additionally, there was no centralized or coordinated approach to data collection, structure, or management according to Kelmelis. Data was acquired from a variety of governmental and private sources, in dozens of non-compatible digital formats, as well as paper maps and documents that needed to be input into the system manually. Moreover different groups compiled their data with varying levels of accuracy and detail, based on their specific usages. Much of what is compiled is too coarse or too inaccurate to meet the needs of the SAST.
      In many cases, the necessary data do not exist in any form. Some information must be compiled for the first time, and the team - along with the many federal, state and local agencies - will need to determine who should be responsible for gathering the data and who should pay for it.
       Now the SAST is pursuing two courses of action: One is the compilation of existing digital and manual data for the large geographic area involved. The other is the creation of previously-uncompiled data for specific analysis.

Monitoring Change
Essential in preparing for future flooding events, the SAST wants to establish a monitoring program to identify changes in the upper Mississippi River basin system. The program, according to the report, should link and integrate ongoing monitoring programs for the physical, ecological and socio-economic sectors of the environment.
      "As government officials establish policy, and that policy is carried out through management of the floodplains, we need a way to track the results of those changes in policy," Kelmelis said. "There are things we just don't know about the water system - much less how our actions will affect it."
      Just as every effort to solve a problem changes the nature and dynamics of the problem, every change to the dynamics of the basin changes the impact and consequences of future floods. "We need a good handle on these details and must be able to use it in determining future development of the area," he said.
      SAST recommends that a number of data themes be monitored, including land use and land cover, ecological indicator species, communities, biological changes, channel changes, structural and non-structural flood control features, location and condition of toxic materials (and dynamics of toxins dispersal under flood conditions), and economic characteristics.
      Kelmelis sees satellite imaging and remote sensing systems as forming the backbone of any monitoring program, along with a variety of gaging stations and meteorological systems that would telemeter continuous data on river characteristics and weather patterns.

Preparing for the Next Flood
While the next flood may not be as severe as the Flood of '93, the simple fact is, the Mississippi and its tributaries will flood again - and often. "We can't expect to stop floods, so we have to find ways to protect ourselves, our property and our natural environment, or at least to mitigate the potential damage. While the report recommends a variety of solutions from structural barriers like levees and flood walls to relocating human activity away from consistently flood-prone areas and restoring those areas to natural habitat, Kelmelis acknowledges the complexity of the task.
      "The dynamics of water flow change dramatically as levels rise," Kelmelis explained. "Our modeling analysis requires extremely detailed information with two-dimensional elevations.
      Kelmelis said the team is currently developing high-resolution two-dimensional digital elevation models for the most critical areas. To achieve the reliability the need, the team is requiring an accuracy of at least 1.4 feet/root mean square error on the floodplains and .67 f/rms error on critical features, with a 5-meter horizontal posting.
      "In planning for the future, two-dimensional modeling will be very useful," Kelmelis said. "Eventually, we'd like to see these detailed elevation models on all the floodplains to facilitate what-if scenarios."
      Kelmelis added, "For example, we need to be able to identify what areas should be prioritized for restoration. These decisions require detailed understanding of variables like the geomorphology of the area, types of species in the habitat, connectivity to the river, and the willingness of area residents to sell and be relocated."

Riding the Internet
As a final piece of the program, Kelmelis notes that the information they accumulate and synthesize must be readily available for everyone who may need it. The team has recommended the formation of a clearinghouse, part of the National Information Infrastructure and available via the Internet.
      "The data and information should be current and available free of charge," Kelmelis emphasized. Consequently, the SAST has established an information clearinghouse that can be accessed on the World Wide Web (WWW). It can be accessed at http://edcwww.cr.usgs.gov/sast-home.html.
      The clearinghouse operates on a distributed model as a node on the Internet. Other organizations which maintain and manage certain portions of the database will ultimately create their own nodes, linked to the central clearinghouse.
      The clearinghouse will maintain and distribute the data and help other organizations design mechanisms to meet quality and distribution requirements, documentation and data compatibility.
      Kelmelis noted that already the USGS, National Wetlands and Biological Sciences agencies have committed to the clearinghouse and negotiations are underway with the Army Corps of Engineers and other agencies.
      "Additional standards will be necessary to make it work, and some of them don't exist yet." Kelmelis said. He would like to see all geotechnology developers and users work together to create translators based on the federally-mandated Spatial Data Transfer Format to allow full compatibility of all the distributed data sets and open the information up to anyone who needs it.

Racing the Clock
But for Kelmelis and the SAST, time is a precious and limited commodity. "We're still working on scientific analysis," Kelmelis said, "We have a lot of work to do."
      And as the task force races to complete its mission, other agencies, charged with similar tasks for the floods in Georgia, Texas and California are watching their progress closely.
      "In Georgia their job is a lot easier, because they can form a one-state consortium," Kelmelis said. "In Texas, I know they're using the SAST model." Of course, in California, it's too soon to think about analysis - they're still trying to cope with the flooding."
      Kelmelis said that, with so many major floods in just the last two years, public awareness for flood control and floodplain management in rising. "There's a definite sense of urgency about it right now," he said, although he acknowledged that the mood in Washington made full funding of any of the task force's recommendation unrealistic.
      "We have to make careful choices about what must be done and what we can afford to do," Kelmelis said.
      Meanwhile, somewhere in the Midwest, it's raining.

About the Author:
J.D. Wilson is a freelance writer in Denver, Colo., specializing in the GeoTechnologies. He may be reached at 303-751-7636.

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