Though this is written specifically about the small dams built mostly by hand, the reasoning for their (and virtually all dams) good impact on the environment remains solid; extra water for fish, wetlands created at the edge of created lakes and other benefits.
Commentary: Check dams--humble structures worth preserving
Issue Date: September 26, 2007
By Elisa Noble
As I stood by the check dam at Bear Lake on a beautiful summer afternoon, I was impressed with the forethought of Fred Leighton and others who recognized the many ecological benefits that check dams could provide. Today, we find ourselves struggling to defend the future management of these dams. I would offer that this decision should not be made from a judge's bench or a federal official's office, but from the edge of Bear Lake…
The original check dam conservation concept was based on the observation that small dams provided natural water storage and slow release into the streams. Over the years, the dams have been maintained by a patchwork of efforts by local sportsmen's clubs, outdoor enthusiasts, trail riders and the aforementioned state and federal agencies.
The check dams essentially raise the level of most lakes by one to two feet. This has created wetlands and meadows in the backwaters of the lakes, which provide habitat for many of the endangered, threatened and sensitive species in the Emigrant Wilderness, such as the Yosemite toad, willow flycatcher, and mountain yellow-legged frog. The increased water table also helps moderate stream flows leaving the mountain lakes. Finally, moderated stream flows and enhanced meadows stabilized many lakeshores that had been washing away due to erosion.
The dams maintain stream flow through the summer months when streambeds would otherwise by dry. This allows vegetation to grow and provides more habitat for species and plants, particularly for the native fisheries. Fish populations improved greatly once the continuous stream flow allowed them to swim upstream to spawn and complete their life cycle. Lakes that were once stocked annually with fish, now maintain naturally reproduced populations. These improvements provide more of a draw for sportsmen and recreationists, thus supporting the surrounding local economies as visitors buy good and services during their travels.
While wilderness legislation prioritizes environmental protection and preservation, it also specifically provides for human use and presence. Science proves that "hands-off" preservation is not necessarily the ultimate ecological scenario. Unfortunately, ideological principles are often endorsed over what is scientifically best for the environment and the community.