rons, major fish spawning and nursing grounds are harmed by the lack of continual silt and gravel replenishment (e.g., Chambers n. pag.).Fish species, nevertheless, are not simply affected by the decreased deposition that occurs below a dam. These, and other aquatic based biota adapted to the natural pulsations of seasonal flooding, can be strained by the regulation of stream flow afforded by a dam (Pielou 145; Leopold 156). Furthermore, moderating the flow may actually retard the entire regime of the river by delaying spring break-up (Pielou 212).Why Remove a Dam?Apart from the precipitous effects on the hydrologic cycle and river-based ecosystems thus far noted, there are an extensive number of further reasons to remove a dam. Briefly, a few of these are (Ocean Planet n. pag.; Pielou 208-09; Trout Unlimited 17; Leopold 156): the restoration of anadromous fish migration and subsequent reliant fisheries ameliorate conditions associated with damming which promote epidemics such as bilharzia and milaria damming has accelerated the rate of earth’s rotation, displaced the axis of the earth, changed the shape of earth’s magnetic field, increased the occurrence of seismic events, and influenced sea level changes dam removal has been shown to improve recreation, tourism, and aesthetics to the associated riverside communities amend the river and groundwater qualityYet for all of the reasons that a dam may be removed, it is often economic and, in part, safety purposes that prompts the decommissioning of a dam. Whether the reservoir has filled with silt, wear-and-tear has taken its toll, or the dam has become obsolete, the benefit of removal may outweigh the cost of maintaining dam operation (PCFFA n. pag.).Consequences Associated with Dam Removal: A Case Study of the Elwha RiverEarly in the 20th century, two hydroelectric dams were built on the Elwha River within the Olympic Peninsula of...
