This series of manuals on Techniques and Methods (TM) describes approved scientific and datacollection procedures and standard methods for planning and executing studies and laboratory analyses. The material is grouped under major subject headings called "books" and further subdivided into sections and chapters. Section A of book 3 is on surface-water techniques. The unit of publication, the chapter, is limited to a narrow field of subject matter. These publications are subject to revision because of experience in use or because of advancement in knowledge, techniques, or equipment, and this format permits flexibility in revision and publication as the need arises. Chapter A24 of book 3 (TM 3-A24) deals with proper identification, evaluation, and temporary preservation of perishable high-water marks for data collection and use as discussed in many of the other chapters in this section. In addition, an appendix introduces the identification of persistent paleoflood evidence left by historical floods.

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Front cover. Left center: USGS personnel launching boat in Janesville, Iowa park. Boat was used to access the streamgage on the Cedar River at Janesville, Iowa (USGS streamgage 05458500). Photograph by Scott Strader, USGS. Upper right: USGS hydrographer analyzing stream velocity data collected in the road overflow caused by West Fork Cedar Creek in Finchford, Iowa (USGS streamgage 05458900). Photograph by Don Becker, USGS. Center right: USGS hydrographer retrieving streamflow measurement instrument temporarily lodged in overbank trees on Long Branch Creek at Atlanta, Missouri (USGS streamgage 06906150). Photograph by C. Shane Barks, USGS. Lower right: USGS hydrographers making a measurement of streamflow on the Gasconade River at Jerome, Missouri (USGS streamgage 06933500). Photograph by Richard Huizinga, USGS.

For more information on the USGS-the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environmentvisit https://www.usgs.gov or call 1-888-ASK-USGS.For an overview of USGS information products, including maps, imagery, and publications, visit https://store.usgs.gov.Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner. AbstractThis field manual provides general guidance for identifying and collecting high-water marks and is meant to be used by field personnel as a quick reference. The field manual describes purposes for collecting and documenting high-water marks along with the most common types of high-water marks. The manual provides a list of suggested field equipment, describes rules of thumb and best practices for finding high-water marks, and describes the importance of evaluating each high-water mark and assigning a numeric uncertainty value as part of the flagging process. The manual also includes an appendix of photographs of a variety of high-water marks obtained from various U.S. Geological Survey field investigations along with general comments about the logic for the assigned uncertainty values.

For more information on the USGS-the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment, visit http://www.usgs.gov or call 1-888-ASK-USGS.For an overview of USGS information products, including maps, imagery, and publications, visit http://www.usgs.gov/pubprodTo order this and other USGS information products, visit