The Hydrologic Analysis Frequency Work Group (HFAWG) met at the office of Michael Baker, Jr. on January 26, 2005. Eleven people attended in person and two by teleconference. The following people attended in person:

The following two people attended by teleconference:
Jery Stedinger, Cornell University
Gary Estes

The following topics were discussed.

Guidance on Regulated Flood Frequency Analysis

The purpose of this report is to describe several methods for regulated flood frequency analysis, to describe the data needed, the applicability, limitations and assumptions, and to provide examples of their application. Those members of the Task Group who have not sent Rocky Durrans a writeup were encouraged to do so. The objective is to have a complete draft before the July 2005 HFAWG meeting.

Scanning Bulletin 17B References

The USGS has scanned all Bulletin 17B references for which it is feasible. Large textbooks, handbooks and mathematical tables were not scanned. All non copyrighted papers (17 in total) have been uploaded to http://water.usgs.gov/osw/bulletin17b/bulletin_17B.html. ASCE has granted permission to upload three references and AGU has granted permission to upload seven papers. Each organization provided guidance on the standard credit line for each citation. There are only 6-7 more references that are feasible to scan. Will Thomas will try to obtain permission to post these references on the above web site.

The work group discussed the option of scanning other papers published since 1982 that are relevant to and supplement Bulletin 17B procedures. The decision was made NOT to scan these more recent references because it would be difficult to determine the most relevant references and would give the false impression that these references are endorsed by the HFAWG. However, it was decided to summarize recent research papers that are pertinent to improving or enhancing methods in Bulletin 17B and to organize these papers by topic such as low outlier detection, historical data adjustment, or generalized skew estimation. Jery Stedinger, Cornell University, has previously volunteered to do this work and was asked to coordinate this effort.

Post-Flood Data Collection

Bill Kirby (USGS), Jeff Harris )USACE):, Mike Eiffe (TVA), and Ken Bullard (BUR) each discussed data collection and analysis activities of their agency after a major flood. We discussed the role our work group should take in coordinating data collection activities such as identifying the type of data that should be collected, the format of data reports, and protocol for making the data available to the public. Don Woodward volunteered to prepare a draft statement for the Subcommittee on Hydrology that would encourage greater coordination among Federal agencies, identify the types of data collection needing more emphasis such as flood damages, the types and frequency of data needed in real time, and suggest improved approaches for making the data available to the public through published reports and the internet. This draft statement will be submitted to the Subcommittee for their consideration and review at the April 2005 meeting.

Needed Research in Flood Frequency Analysis

Rick McCuen, University of Maryland, suggested that the HFAWG prepare a paper on needed research in flood frequency analysis to encourage meaningful research within academia. Jery Stedinger, Cornell University, suggested that we should evaluate recently completed research that may be applicable to revising Bulletin 17B. Jery believes that recently completed research on the Expected Moments Algorithm (EMA), improved confidence intervals and skew estimation should be incorporated into Bulletin 17B. Bill Kirby stated that the USGS is preparing a windows version of their Bulletin 17B program PEAKFQ, it will include EMA, and it will be available in a few months. Jeff Harris reported that USACE is developing a windows version of their Bulletin 17B program HEC-FFA, it will include EMA, and be available by the end of the 2005 fiscal year. Ken Bullard reported that the Bureau has a flood frequency program that also includes EMA and that John England (BUR) has done limited testing of the EMA method. It was agreed that these programs will provide a basis for future testing of the EMA method. A testing protocol or plan will be developed to determine if EMA is a significant improvement.

Joe Krolak suggested that there is a need to evaluate methods for estimating the more frequent floods (~ 2 year floods) for stream restoration, fish passage, and storm water management and to develop standard procedures for frequency analysis of coastal storm surges. Bill Kirby suggested that research is needed on ways to analyze flood events that include debris flows. Jerry Coffey suggested that a mixture of frequency distributions is the way to analyze combined coastal-riverine flood events and clear water-debris flow events. Contingent upon Subcommittee approval, the HFAWG agreed that a paper on "Research and Development Needs in Flood Frequency Analysis" should be prepared. Jery Stedinger and Will Thomas will coordinate the development of this paper and will get input from all HFAWG members. An outline of this paper will be presented to the Subcommittee at their April 2005 meeting. The full paper will identify and prioritize the important research that has been recently completed or that should be pursued; the paper will be published in a technical journal or presented at a technical conference.

The HFAWG agreed that if the EMA method and improved confidence limits and skew estimation are eventually implemented into Bulletin 17B, these changes are sufficiently different to justify development of a new Bulletin 17C.

Next meeting

The next meeting of the HFAWG will be scheduled to be consistent with the July 2005 meeting of the Subcommittee on Hydrology.

Will Thomas, Chair
Hydrologic Frequency Analysis Work Group
January 26, 2005