Chapter 11, Additional Exercise 3: Creating Thumbnails for an Improved Design
The following excerpt from a report by the Bonneville Power Administration (1993) is underdesigned. Draw three different thumbnail sketches for a new, more interesting design that would better emphasize important information.
2.2.5 Anadromous Fish
Columbia River Basin
The Pacific Northwest supports a large number of anadromous fish (species that migrate downriver to the ocean to mature, then return upstream to spawn). The principal anadromous fish runs in the Columbia Basin are chinook, coho, sockeye salmon, and steelhead trout.
These fish are an important resource to the Pacific Northwest, both for their economic value to the sport and commercial fisheries and for their cultural and religious value to the region's Indian tribes and others.
The development of dam and reservoir projects on the Columbia and Snake Rivers and tributaries has reshaped the natural flows of these rivers. The use of storage reservoirs to capture runoff for later release results in reduced flows during the spring and early summer, when juvenile salmon and steelhead are migrating downstream to the ocean. Water velocities have also been reduced as a result of the increased cross-sectional area of the river due to run-of-river projects. These changes have slowed juvenile fish migration, exposing juvenile salmon and steelhead to predation and disease and impairing their ability to adapt to salt water when they reach the ocean. Additional mortality occurs as fish attempt to pass each dam on their downstream migration to the ocean.
Flow: Flow plays an important part in moving juvenile fish downstream to the ocean. In 1982, the Northwest Power Planning Council established a specific volume of water, known as the water budget, to increase river flows during the April 15 through June 15 period. This coincides with the peak out-migration of spring fish (predominately yearling chinook, steelhead, and sockeye), which depend on adequate river flow, particularly velocity, for a successful migration. The federal hydro system is operated to provide this water each year.
Not only is flow important for moving juvenile fish downstream past the dams, but flow is an important component of ensuring successful spawning and emergence of fall chinook on Vernita Bar (a gravel bar used by spawning fall chinook, located in the Hanford Reach of the Columbia River, downstream from Priest Rapids Dam). In 1988, BPA and the mid-Columbia operators signed a long-term Vernita Bar Agreement, which specifies protection requirements for fall chinook spawning, incubation and emergence on Vernita Bar.
Spill: Until adequate bypass systems are installed at all the dams, spill remains a necessary means of moving juvenile fish past dams. Planned fish spill now includes the negotiated Spill Agreement, as well as a restricted operation at Bonneville Dam by the Corps. Planned spill also includes spill levels specified by the federal Energy Regulatory Commission for non-federal projects. Planned spill does not include overgeneration spill (water which is spilled because there is no market for the energy it would produce) and is not changed as a result of the resource additions. Planned fish spills are met under all water conditions.