The in situ productivity of both the phytoplankton and the macro- phytes in Marion Lake, B.C., was determined from April 1966 through September 1966, by using ¹⁴C techniques. The uptake of NaH¹⁴CO₃ was measured in selected macrophytes by enclosing them in plexiglass chambers. These plants were then combusted in oxygen, and the ¹⁴CO₂ was absorbed in toluene-POPOP-ethanolamine. Radioassay was accomplished by liquid scintillation. In addition to the ¹⁴C method, an organic weight method was used to measure macrophytic productivity. The productivity of the macrophytes was always higher than that of the phytoplankton. There was a considerable difference in the estimates of the macrophyte productivity arrived at by the two different methods, and reasons for this are discussed. The total productivity of the lake is very low when compared with lakes of similar latitudes because of low phytoplankton productivity. It is concluded that in Marion Lake the macrophytes are more important primary producers than the phytoplankton. The difficulty of comparing data between this and other studies is discussed, and the need for standardization of methods is emphasized. / Science, Faculty of / Zoology, Department of / Graduate

Annual and seasonal changes in distribution and abundance of six species of macro-zooplankton (Cyclops bicuspidatus thomasi, Diaptomus ashlandi, Daphnia galeata mendotae, Diaph- anosoma leuchtenbergianum, Bosmina coregoni, and Mysxs relicta.) twgre studied in Kootenay Lake, a body of water extending over 105 km in southeastern British Columbia. Differences between two years, 1949 and 1964, were examined as well as changes in midsummer distribution and abundance between three consecutive years (1964 to 1966). Seasonal changes during one year and within a summer were also noted as well as diel changes in distribution and abundance. A large increase in zooplankton abundance occurred during the fifteen year period from 1949 to 1964, and this was attributed to an increased inflow of primary nutrients from a major tributary at the south end of the lake. A change in species composition, formerly dominated by Daphnia but now by Diaphanosoma, was related with eutrophication. Changes in food availability due to eutoophication, competition for food with Mysis relicta, and heavy predation by kokanee (Oncorhynchus nerka), were examined as factors possibly responsible for changes in the spatial distribution of Daphnia since 1949. Differences in the midsummer zooplankton distribution and abundance between three consecutive years (1964 to 1966) were minor, suggesting that the changes noted between 1949 and 1964 were attributable to large changes in limnological conditions and not merely the result of annual fluctuations. Examination of seasonal trends in zooplankton distribution and abundance indicated that zooplankton, with the exception of Mysis relicta, were most abundant during the summer. Mysids were most abundant in May when the young mysids were released from the brood pouch. Spatial differences in summer zooplankton abundance was examined in relation to wind-driven currents, and food availability. Spatial differences during the rest of the year were minor, possibly a result of similar limnological conditions at all stations then. Abundance of Mysis relicta was greatest in the north arm of the lake, whereas all other species were most abundant in the central area of the lake. Changes that occurred within the summer were largely due to high turbidity in the south arm during June and July. Diel changes in the vertical distribution of zooplankton, with the exception of Mysis relicta, were not detected. / Science, Faculty of / Zoology, Department of / Graduate

The object of this study is to establish the stratigraphy, structure, and petrology of early Tertiary rocks in the White Lake area near Penticton, British Columbia. This is achieved by field mapping and laboratory work. Early Tertiary rocks of the White Lake area, thought to be mainly Eocene age, consist of five main stratigraphic division; 1. discontinuous beds of basal breccia and conglomerate, 2. a thick and widely distributed succession of volcanic rocks of diverse composition - mainly phonolite, trachyte, and andesite lavas, 3. discontinuous volcanic beds - mainly rhyodacite lava, 4. locally thick volcanic sandstone and conglomerate beds inter-digitated with lahar and pyroclastic deposits, 5. local deposits of slide breccia and some volcanic rock overlain by fanglomerate beds. Each division rests with some angular or erosional unconformity on older rock. Aggregate thickness of the Tertiary strata, where best developed, is about 12,000 feet. These rocks are regionally downfaulted accounting, in part, for their preservation from erosion. Greatest downward movement is near the Okanagan Valley where, in places, it is estimated that basal beds exceed depths of -5,000 feet (m.s.l.). In general, beds are tilted easterly as if rotated downward forming a trap-door-like structure. Locally, folds are developed but these are without regional pattern and may be the result of simple flextures in the basement rocks. Petrographic and chemical data indicates a three-fold division of igneous rocks: 'A' series - mainly plagioclase porphyries; lavas of rhyodacite and andesite composition; 'B’ series - mainly two feldspar porphyries with co-existing plagioclase and sanidine; lavas of trachyte and trachyandesite composition; 'C’ series - mainly anorthoclase porphyries; lavas of phonolite composition and some tephrite. Phase diagrams and subtraction plots indicate that rocks of 'A' and 'C’ series were probably formed by crystal fractionation. In the case of 'A' series, precipitation of mainly plagioclase and pyroxene from andesite produces rhyolite; and for 'C’ series, precipitation of mainly pyroxene and some biotite from tephrite produces phonolite. Rocks of 'B’ series are intermediate in composition to 'A' and 'C’ and were probably formed by mixing of magmas. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

The purpose of this thesis was to study the geomagnetic variation anomaly at Kootenay Lake, B.C., first reported by Hyndman in 1963. The anomaly is characterized by a very high correlation between the vertical and horizontal north-south geomagnetic components; this indicates anomalous currents striking magnetic east-west, to the south of Kootenay Lake. During the summer of 1968, twenty recording stations were set up in the Kootenay Lake area, using four Askania variographs and three fluxgate magnetometers. Spectral analysis shows that the main 'low I - high I' discontinuity was traversed over a relatively short distance on a north-south profile, to the south of Kootenay Lake. Polarization studies indicate anomalous currents striking magnetic east-west in the same general area of the above discontinuity. The model proposed is a localized distortion of the main 'low I - high I’ discontinuity, resulting in a well defined conductivity step, striking magnetic east-west, to the south of Kootenay Lake. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

This study investigates the operational decision process for Okanagan Lake, a natural lake regulated by a dam at the outlet for flood control, irrigation and water supply purposes. In addition, the Lake supports a substantial tourist industry. The Lake is principally supplied by snowmelt and a forecast of total inflow volume during the critical runoff season is available to assist the operator. The operational decision process was found to differ from the sequential decision basis of many Operations Research techniques and the absence of information on costs and benefits precluded the use of conventional optimization procedures. The importance of making the best use of the inflow forecast to achieve the operational goals was recognized and was used as the basis of the decision analysis developed. The method developed assesses possible immediate operational decisions by evaluating the effectiveness of future discharges to correct for past decision errors. The evaluation is made in terms of the probabilities of exceeding Operational constraints and of achieving operational goals. The method involves simulation of sets of monthly inflows for the remainder of the runoff season given an inflow volume forecast and knowledge of the probable accuracy of the forecast; computation of water levels which would occur with various operating procedures; frequency analysis of the resulting levels; interpretation of the frequencies as probabilities; and presentation of the resulting information describing the operational situation in readily assimilable form. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

This study was conducted to identify aspects of the breeding ecology of white pelicans (Pelecanus erythrorhynchos) in British Columbia and to develop a management plan to preserve and enhance white pelicans and their habitat in British Columbia. Field studies were conducted during the breeding seasons from 1977 to 1980. The major migratory route of white pelicans in British Columbia occurs in the Okanagan Valley. Pelicans arrive at Stum Lake, the only known breeding location in British Columbia, in mid April and remain on the Fraser Plateau until late September. Eighty-three percent of all pelicans observed in British Columbia during the summer were located within 80 km of the breeding lake. Chilcotin Lake, approximately 70 km west of Stum Lake, was the primary foraging site during the study. Identification of bone samples collected on the breeding island indicate that pelicans in British Columbia prey chiefly on non-game fish species, such as sucker (Catostomus spp.). Pelicans at Stum Lake selected flat unvegetated areas to nest. The presence of herring gulls (Larus argentatus) did not appear to affect their nesting distribution. Inter-nest distances were calculated in 1977 and 1978 and found to be similar to distances recorded for other white pelican colonies in North America. Mean clutch size of white pelicans at Stum Lake during years without disturbance was 1.95 ± 0.21. Mean egg mortality was 10% of all eggs laid. Nest abandonment was the major mortality factor. Nestling and fledgling mortality claimed a further 26% and 20% respectively, of all eggs laid. Total mortality of young during 1977 and 1978 was 56% of all eggs produced. In years when coyote predation or human disturbance occurred, survivorship of young, and overall productivity of the colony was reduced. The potential impact of coyote predation and human disturbance were examined over longer periods by using a simple simulation model. The results of this study were discussed in terms of potential management practices that would enhance white pelicans in British Columbia. / Forestry, Faculty of / Graduate

The City of South Lake Tahoe currently does not have an adopted subdivision ordinance. This has caused confusion about the approval process and regulatory requirements as well as delays in application processing. This Professional Project will explore the opportunity for the City to adopt a subdivision ordinance that would provide direction for subdivision design and approval and further the City’s smart growth and sustainability policies. However, there would need to be careful consideration for the potential increase in costs that are associated with additional fees or off-site improvement requirements. The Subdivision Ordinance would be written with the goals of achieving a streamlined process and incorporating design standards consistent with smart growth principles and sustainability consistent with the City’s Sustainability Plan. In addition, the Subdivision Ordinance must be consistent with the goals, policies, and programs of the City of South Lake Tahoe General Plan. The project would begin with a literature review on subdivision regulation and the regulatory environment in South Lake Tahoe. Several subdivision ordinances would be reviewed for their ability to meet the goals of the South Lake Tahoe Ordinance. Throughout the process there will be consultation with other professionals. The final product will be a draft subdivision ordinance and an analysis of how well the draft achieves the goals.

This study was undertaken to examine any possible associations between the measurements of water quality and lake conditions, and the quantity and composition of plankton present in Upper Blue Lake, Lower Blue Lake, and the Oaks Arm of Clear Lake during the sampling period. A secondary objective of this study was to provide a record of these measurements. These measurements, when taken collectively, are important indicators of the trophic state or nutrient condition of the waters of the three lakes from February through October 1972.

Surrounding land-use and in-lake data were collected to determine environmental variables influential in structuring centrarchid assemblages in oxbow lakes of the Mississippi Alluvial Valley (MAV) and to suggest environmental manipulation strategies that may improve the fisheries of these systems. I sampled 53 oxbow lakes using boat electrofishing and land-use data were summarized using ArcView GIS. Non-metric Multidimensional Scaling separated centrarchids according to water quality tolerance. Centrarchid composition was related to land-use, water clarity, maximum depth, connectivity, primary productivity, and physicochemistry as determined by Canonical Analysis of Principal Coordinates. Canonical Correspondence Analysis rejected the null hypothesis of no relationship between land-use and centrarchid proportional composition. Environmental variables were related significantly to centrarchid composition. Based on these data, a general fisheries management plan for oxbow lakes of the MAV was proposed.

No description available.