Graduation date: 1993

This study measured and evaluated the relation of coastal foredune morphology to stream beach outlets, and investigated the processes associated with the stream outlet. Intermediate-size streams were studied, and defined as those that flow across the beach most of the year but have no tidal influence. Fifty-four of these streams were found along the northern Oregon coast between the Columbia River and Yaquina Bay. Crescent Lake Outlet, Saltair Creek and Daley Lake Outlet were chosen as study streams for further investigation.

Few studies, and none in Oregon, have examined the presence and change of water quality parameters over time in popular natural swimming areas. This information is necessary to better understand water quality and risk of illness from either fecal contamination or cross-infection from other swimmers. The purpose of this study was to quantitatively measure bacterial and selected physical and chemical parameters, and collect background information for changes to the current state water quality criteria. Five natural swimming areas in Linn, Benton and Polk counties were chosen and sampled biweekly for physical, chemical, and bacterial parameters over a nine week period from June 28 to August 31, 1996. The results showed differences in bacterial levels over the sampling period which often varied by degrees of magnitude between sites. For example, the range in Escherichia coli levels was between 0 and 1000 colonies/100mL sample for two sites on the same sampling day. Similarly, the range in fecal coliform levels was between 5 and 500 colonies/100mL sample. The daily colony counts at each site exceeded the state standards at least 10% of the time for E. coli and 21% of the time for fecal coliform. At the most popular swimming site, Montieth Park. the fecal coliform regulatory levels were exceeded 79% of the time and E. coli levels were exceeded 42% of the time. This may be due to turbidity, high bather load, or a broken sewer line. The 30 day log mean of these values shows consistently elevated fecal coliform problems only at Montieth Park. For the other sites, the log means did not exceed the state and federal regulatory limits for fecal coliform or E. coll. This raises questions about which estimates should be used to assess public health risk. None of the other parameters in this study were correlated with bacterial counts, so it appears that none of these factors is solely responsible for elevated bacterial levels. Further testing should be done at Montieth Park to determine the cause of the elevated fecal coliform levels. Any follow-up studies should test several different indicator organisms in addition to E. coli for comparison and assessment of their relationship to public health risk. / Graduation date: 1997

Twelve stream segments in the Silvies River drainage system were classified in the fall of 1993 and again in 1994, using a morphological classification of natural rivers (Rosgen 1994). Bankfull flow of stream channels is the key feature of this system. Measurement of bankfull is used in the calculation of entrenchment ratio and width/depth ratio. Analysis of the differences of the averages between years in bankfull measurements showed that despite being consistently repeated at the same locations along the channel, the measurements were found to be different (p=0.000163 for entrenchment ratios and p = 0.0208 for width/depth ratios). Bankfull was found to be a non-repeatable field measure, therefore, a poor benchmark for a classification scheme. Historical information collected for the study area indicated a history of domestic livestock use that dates back as far as the mid-nineteenth century. Although grazed by livestock for several years, settlement of the Bear and Silvies Valleys occurred mostly around the turn of the twentieth century after the stockgrower's homestead acts were passed. Ownership today is dominated by large (relative to the homestead days) ranches. / Graduation date: 1996