Date of Award:

1979

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Ecology

Advisor/Chair:

William J. Grenney

Abstract

Ogden Bay Waterfowl Management Area is one of many marshlands bordering the Great Salt Lake that are extremely important as breeding habitats for North American waterfowl. Salinity, both of surface and interstitial waters, is an important factor in maintaining a suitable habitat within the marsh. For this reason, a study was undertaken to determine the factors affecting the salinity of surface and interstitial waters. A small (approx. 100 acre) subunit was studied extensively to determine; 1) variations in surface water salinity with flowrate and water level; and 2) variation in interstitial water salinity with depth and location within the subunit. Field data indicated a substantial increase in salinity (as measured by electrical conductance) with depth in the interstitial waters. Wide variation in interstitial water conductivities was also observed within the study unit. Of major significance were large increases in interstitial water salinities in areas where the soil had dried, due to a low water level, and again re-wetted. This was in contrast to relatively constant soil water salinily observed in areas that were perenially flooded In addition to the field study, a laboratory study, using three 20 cm diameter undisturbed soil cores, was performed to determine the factors affecting the movement of salts through the marsh soils. The surface and bottom of the cores were fed with fresh water and brine, respectively, for a period of three months, while interstitial water samples were taken to monitor changes in soil water conductivities with depth of soil. A computer model was developed to simulate the experiment, as well as to help interpret the experimental results. The comparison between the observed data and data predicted by the model, as well as the results of the field data,' indicated that the major mechanisms affecting fluctuations in soil water salinity in the Ogden Bay marsh system is the movement of water through the soil.

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