No abstract

USDA Forest Service Gen. Tech. Rep. PSW-104. 1988 'Unless otherwise noted, available and unpublisheddata areon file in the SDEF archives at the Forest Fire Laboratory,4955 CanyonCrest Drive, Riverside, California 92507.

No abstract

Two types of small (30-cm aperture) sheet metal sediment traps were developed to monitor onslope surface sediment transport. Traditionally, sediment traps and erosion pins have been used to measure the onslope movement of surficial soil material. While pins may be appropriate for documentinglandscapedenudation, traps aremoresuitable for monitoring downslope transport parallel to the ground surface. Previous investigations used large (3-m aperture) traps to measure sediment transport. However, large aperture traps are cumbersome and require excessive amounts of time and energy for installation, sample collection, and sample processing. These serious logistical constraints make data acquisition difficult and expensive. The small traps were designed to remedy this situation. Reld tests of these small traps revealed variable patterns of spatial and temporal surficial debris movement obscured in previous studies. Although these traps are not without limitations, the improved sampling logistics allow greater sample sizes andconstituteamarkedimprovement over other transport measurement techniques.

This paper describes a system for simulating tidal movements in an enclosed salt-water (estuarine) environment. This Tidal Simulation System (TSS) can be programmed to deliver various tide levels on variable cycles, and can record system performance analog data output on strip charts. Employing a variable-speed centrifugal pump, a system of pneumatic valves actuated by a central timing device, a pressurization subsystem, and a special piping manifold, the system controls flow through a branched array of submerged outlet pipes which prevent disruption of surface water and oil films, and prevent disturbance of bottom sediments. The system has undergone extensive operation tests in the Ecosystem Research Laboratory of the Mississippi State University Research Center, situated at the NASA National Space Technology Laboratory (NSTL) at Bay St. Louis, Mississippi, and has been used to simulate tides in two pairs of ponds which were employed on an Environmental Protection Agency contract to study the fate and effect of oil in the aquatic environment of the Gulf Coast Region. The salinity of the ponds ranged from 6 to 12 parts per thousand (‰), and the composition of the plankton population changed with salinity and paralleled changes observed in the estuarine area of the south-central Gulf area. Several effects of low level oil pollution, not found in laboratory studies, were observed during the course of an eleven-month study.