Dam removal continues to garner attention as a potential river restoration tool. The increasing possibility of dam removal through the FERC relicensing process, as well as through federal and state agency actions, makes a critical examination of the ecological benefits and costs essential. This paper reviews the possible ecological impacts of dam removal using various case studies. Restoration of an unregulated flow regime has resulted in increased biotic diversity through the enhancement of preferred spawning grounds or other habitat. By returning riverine conditions and sediment transport to formerly impounded areas, riffle/pool sequences, gravel, and cobble have reappeared, along with increases in biotic diversity. Fish passage has been another benefit of dam removal. However, the disappearance of the reservoir may also affect certain publicly desirable fisheries. Short-term ecological impacts of dam removal include an increased sediment load that may cause suffocation and abrasion to various biota and habitats. However, several recorded dam removals have suggested that the increased sediment load caused by removal should be a short-term effect. Pre-removal studies for contaminated sediment may be effective at controlling toxic release problems. Although monitoring and dam removal studies are limited, a continued examination of the possible ecological impacts is important for quantifying the resistance and resilience of aquatic ecosystems. Dam removal, although controversial, is an important alternative for river restoration.

This report prepared by American Rivers, Friends of the Earth and Trout Unlimited in 1999 describes the concept of dam removal and discusses the brief history of dam removal in the United States until then. Case studies of dam removal in many states are also discussed.

According to the report, until 1999, states with the most recorded removals were Wisconsin (73 dams), California (47 dams), Ohio (39 dams), Pennsylvania (38dams), and Tennessee (25 dams).

This paper presents the results of an ex post survey of recreational anglers for the lower Kennebec River, post-Edwards Dam removal. To the best of our knowledge, this study represents one of the first ex post analyses of fisheries restoration from dam removal. We find significant benefits have accrued to anglers using the restored fishery. Specifically, anglers are spending more to visit the fishery, a direct indication of the increased value anglers place on the improved fishery. Anglers are also willing to pay for increased angling opportunities on the river. These findings have policy implications for other privately owned dams that are currently undergoing relicensing and ⁄ or dam removal considerations. Our findings may also hold implications for fisheries that have deteriorated due to historic dam construction.

Too often advocates for river restoration through dam removal find themselves in the middle of a project and at odds with potential partners over matters of historic preservation. The goal of Dam Removal and Historic Preservation: Reconciling Dual Objectives is to help dam removal proponents and advocates for historic preservation work together more effectively to achieve their mutual goals, while building constructive relationships and successfully reconciling potentially competing objectives. This report combines a primer on Section 106 of the National Historic Preservation Act with methods for avoiding, minimizing, or mitigating the adverse effects of a dam removal project and concludes with real life case studies.

Available online at http://www.americanrivers.org/site/DocServer/Dam_Removal_and_Historic_Preservation.pdf?docID=8161 

This article presents the results of a hedonic property value analysis for multiple hydropower sites along the Kennebec River in Maine, including the former site of the Edwards Dam in Augusta, Maine. The effect of the removal of the Edwards Dam on the Kennebec River in Maine is examined through consumer's marginal willingness to pay to be close to or distant from the dam site. Data from both before and after the dam was removed are used to estimate changes in marginal prices. A similar data set is also used to look at the effects of the remaining upstream dams on property values.
This article presents one of the first (to our knowledge) ex post analyses on the economic impact of dam removal on property values. As more privately owned dams in the United States come up for relicensing, evaluating the impacts with and without the dam will become increasingly important. This work can help inform those analyses.

This paper uses hedonic analysis to examine the impact of small dam removal on property values in south-central Wisconsin. Data on residential property sales wereobtained for three categories of sites: those where a small dam remains intact, thosewhere a small dam was removed, and those where a river or stream has been free flowing for at least 20 yr. The primary conclusions that emerge from the data arethat shoreline frontage along small impoundments confers no increase in residentialproperty value compared to frontage along free-flowing streams and that nonfrontage residential property located in the vicinity of a free-flowing stream is more valuablethan similar nonfrontage property in the vicinity of a small impoundment.