Annual Report of the Chief of Engineers
on Civil Works Activities
Fiscal Year 1981
Department of the Army Corps of Engineers
Extract Report of Walla Walla District
Research and Development
A cooperative research program between the Walla Walla District and the Waterways Experiment Station is being conducted as part of a nationwide survey to investigate the effects of fluctuating water levels upon riparian shorelines and vegetation. An experimental pond, which approximates the proposed worst-case conditions of peaking on McNary Reservoir through the use of pumps, automatic timers, and water control gates, and two shoreline plots in the reservoir itself are the test sites used for the plantings.
Through this research species are being identified which can be expected to survive various periods of flooding. Species which produce cover at the water's edge, and woody species which can survive the periods of flooding are still under investigation. The effects of winter ice damage have also been considered with stable and fluctuating pool levels. In the control pool with stable water levels minimal ice damage occurred, whereas many plants were uprooted and destroyed by ice forming at the edge of the fluctuating water surface.
McNary Lock and Dam, Lake Wallula, has also been designated a Recreation Research and Demonstration Unit under agreement with the Waterways Experiment Station. Two research units have been completed to date: Recreation Carrying Capacity, Design and Management; and a study on the Methodology to Determine Concessionaire Opportunity. A Campground Use Monitoring Study is currently underway.
In FY 1981, the Walla Walla District combined previous independent efforts with the Waterways Experiment Station in studies on Thermal Stress. This cooperative program will develop a series of computer programs and mathematical models to evaluate the generation of internal heat in mass concrete structures, both during and after hydration, as well as the internal stresses caused by the thermal changes. The study will include new developments in modeling techniques and boundary conditions to determine the applications to creep modeling, stress relocation methods, and determinants of concrete material properties at early stages. Data from this study has been incorporated in the design of Willow Creek Dam.