BRIEF CRITIQUE OF THE SHASTA RESERVOIR
BY JIM BROBECK, AQUALLIANCE, CA
There is a big difference between a lake and a reservoir. Lakes have natural water level fluctuations that enhance ecosystems. Reservoirs like Shasta have extreme fluctuations that destroy life. I never call this body of water “Lake” Shasta … I call it Shasta Reservoir.
Reservoir operation always results in denuding the acres of inundation. People that promote raising Shasta Dam never reveal the obvious: the natural vegetated landscape would be completely denuded and converted into a dead eroding boundary. Raising the dam would increase the dead zone around the entire reservoir. The elimination of vegetation that currently serves to reduce storm runoff erosion would increase siltation and reduce the lifespan of the reservoir as it fills with silt.
Riparian areas are lands that occur along streams and rivers. The filling, release and re-filling of the reservoir destroys the Riparian ecosystem that exists in the streams that are currently above the reservoir level. Riparian zones are both rich in life and contribute to water quality. Riparian areas provide important habitat for many endangered and threatened species and other wildlife and plants. Riparian vegetation can remove excess nutrients and sediment from surface runoff. Although riparian ecosystems generally occupy small areas on the landscape, they are usually more diverse and have more plants and animals than adjacent upland areas. Reservoirs such as Shasta obliterate Riparian ecosystems and replace them with dead zones. The existing zone of death perimeter of Shasta Reservoir is about 365 miles and uncounted thousands of acres of bare, eroding soil. Raising the dam would massacre many more miles of existing forest and riparian habitat and add thousands of more dead acres.
The extreme Water Level Fluctuations [WLF] destroy the transitional habitats or ecotones [littoral zones] that exist at natural lake edges. Lakes have gentler and less extreme WLF. Because littoral zones constitute habitats for both terrestrial and aquatic organisms they produce high biodiversity in comparison with the open water. A diverse assemblage of microorganisms, algae, and micro-invertebrates colonizes the littoral. Macroinvertebrate and fish grazers, predators, and birds, exploit these rich food resources. The diverse structure that evolves in the littoral zone creates refuge for prey organisms and are often used as preferred fish spawning sites.
Many fish inhabit the littoral for parts of, if not their entire, life cycle. The diverse species inhabiting littoral habitats have evolved with adaptations to the natural regime of Water Level Fluctuation [WLF]; eliminating natural fluctuation regime eliminates the entire ecosystem.