REPLY TO DISCUSSION by Jeffrey A. Thornton 1

work: (1) little consideration was given for downstream sedimentation following dam removal, and (2) dam removal removes an existing lacustrine ecosystem. We begin by reexpressing the original purpose of our paper: because dams have been removed, are being removed, and will be removed with increasing frequency over the next several decades (Pohl, 2002), and because of the lack of science on the subject of dam removal, we have encouraged scientists to take a systematic and deliberate approach to understanding the environmental impacts of dam removal (Doyle et al., 2003c). Our article was intended not to advocate for removing dams, but rather to show that there is a vast existing body of geomorphic literature that is applicable to dam removal (see also Pizzuto, 2002). We wrote this paper as a first step toward knowledge building (i.e., establishing what we think might happen when a dam is removed). A logical next step would be to undertake some experimental dam removals, as we did on the Koshkonong River and other rivers in Wisconsin (Stanley et al., 2002; Doyle et al., 2003a). Thus, we resist the suggestion by the discussant that we, or the Wisconsin Department of Natural Resources (WDNR) ‘failed to recognize’ the important issue of downstream sedimentation following dam removal. Rather, it was particularly because of our recognition of this important topic that we undertook deliberate and systematic studies of dam removal, without calling for engineering intervention to restrict natural erosion and sedimentation processes following the removals. Further, while the WDNR often attempts some sediment stabilization in association with a removal as the discussant suggests, they allowed our sites to adjust naturally in the year following the removal so that we could document physical and biological adjustments following dam removal. They should be commended for their foresight in recognizing the need for scientific studies of dam removal. The insight gained from these and other similar studies is irreplaceable for developing a scientific basis for dam removal, and we suggest other state and federal agencies develop similar programs to increase overall understanding of dam removal. Our studies showed that downstream reaches were able to convey the sediment without major downstream geomorphic adjustments (Doyle et al., 2003a), and that many attributes of the local stream ecosystems can recover within two to five years (or less) following removal (Stanley et al., 2002). While our results are far from universally applicable to all dam removal cases (Egan and Pizzuto, 2000; Doyle et al., 2003a), now that some scientific understanding of how channels respond to dam removal is available, it is possible to make more informed recommendations on how to reduce the environmental impacts of removal. Further, it is possible to suggest whether engineering interventions are necessary given the natural rates of recovery, as were documented in our studies. Based on our results, engineering intervention may not be justified in all cases, and this finding is in contrast the suggestion of the discussant that sediment derived from the removal would overwhelm downstream ecosystems.