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250 J. R. SHUMAN Table I. States with the most and fewest dams States with the most dams States with the fewest dams Texas 6342 Delaware 73 Kansas 5699 Hawaii 129 Oklahoma 4532 Alaska 145 Georgia 4331 Rhode Island 189 Missouri 3541 Maryland 262 Montana 3282 Vermont 335 Mississippi 3193 Louisiana 346 North Carolina 2685 Nevada 399 Iowa 2465 Idaho 416 South Dakota 2336 Arizona 430 Source: FEMA (1993) Decisions are now becoming necessary regarding the fate of a large number of dams which are in need of rehabilitation or relicensing, or which are deemed to be environmentally damaging. It is now clear that dam removal is a reasonable, and in many cases viable, alternative in assessments regarding the fate of dams. Assessment of the various dam retention/rehabilitation/modification and dam removal alternatives is both complex and frequently controversial. It is also clear from a review of past dam removals that it may be environmentally unwise to simply open up or breach the dam and allow `nature' to restore the river ecosystem. This paper provides a selected review of dam removals in the USA and discusses some of the environ- mental considerations apparent from those removals. A current project involving the assessment of dam retention and dam removal alternatives is then discussed in detail. This project focuses on the environmental attributes of retaining or removing Rodman Dam on the Ocklawaha River in Florida. The decision on whether to keep or remove this dam has been highly controversial for over two decades. The assessment approach utilized in the Rodman Project was based on knowledge gained from past dam removals and was developed to assure a holistic and ecosystem-based approach for making a decision on the fate of this dam. SYNOPTIC HISTORY OF DAM REMOVAL Information from past and currently proposed dam removals are instructive in understanding the environmental consequences and considerations for assessing dam removal as an alternative for the fate of dams (Table II). However, because virtually no data on dam removal is documented in peer-reviewed publications, it was necessary to rely heavily on grey literature and unpublished reports when compiling the information in this paper. It should be noted that dam removals documented in reports and grey literature probably represent a minority of the total number of dams intentionally breached or removed. Information gathered from Federal and State agencies suggests that there have probably been hundreds of dams intentionally breached or removed in this country, but the vast majority of them have been small in size. One of the earliest dam removals reported is the Washington Water Power Dam on the South Fork of the Clearwater River in Idaho. The South Fork of the Clearwater River is a tributary to the Clearwater River, which is a tributary to the Snake River. This dam, built in 1927, had totally eliminated anadromous fish migrations in the South Fork of the Clearwater River (Hair and Stowell, 1986). The dam was completely removed in 1962 and salmonid stocking and habitat improvement programmes have continued since then, resulting in the return of small steelhead and chinook salmon runs in the river. Their status, however, continues to be in jeopardy because of downstream dams on the mainstem Snake River (Idaho Department of Fish and Game, pers. comm.).