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A Hydrologic Analysis of Government Island, OregonBittinger, Scott Gregory 04 May 1995 (has links)
Government Island, located in the Columbia River approximately 16 km (10 mi) upstream of the confluence with the Willamette River, is a wetland mitigation site prompted by expansion of the southwest quadrant of Portland International Airport. The purpose of the study is to predict water levels in two enclosed lowland areas, Jewit Lake and Southeast Pond, based on levels of the Columbia River, precipitation, and evapotranspiration. Mitigation is intended to convert 1.13 km2 (237 acres) of seasonally flooded wetland to 1.27 km2 (267 acres) of semi-permanently flooded wetland and seasonally flooded wetland. Flooding of the wetland is most likely to occur December through January and May through early June when Columbia River water levels at Government Island exceed 3.6 m (12 ft) m.s.l. Flooding of Jewit Lake occurs through a channel connecting the wetland to the Columbia River. A groundwater model (MODFLOW) was parameterized to simulate the hydrology of the wetland. Observations of the subsurface stratigraphy in 25 soil pits, bucket auger cores, and during installation of water monitoring devices were used to estimate thickness and lateral extent of a confining unit that overlies an aquifer. Climatological data for 1994 and water levels were entered into MODFLOW to calibrate rates of water movement through the subsurface. Periods of drying for Jewit Lake and Southeast Pond were predicted based on precipitation and actual evapotranspiration rates expected to be present in the study area between June and December. Results of groundwater modeling show that Jewit Lake will maintain surface water above 3.6 m (12 ft) in most years. Southeast Pond is expected to dry annually as mitigation is unlikely to change the hydrology of Southeast Pond. Groundwater modeling predicted the types of wetlands present at different elevations by evaluating periods of drying within the wetland using the U.S. Fish and Wildlife Service classification of wetlands method. Results suggest that Jewit Lake will be converted to semipermanently flooded wetland below 3.6 m (12 ft) in elevation. Southeast Pond will remain a seasonally flooded wetland as a result of mitigation.
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Hydrological applications of MLP neural networks with back-propagationFernando, Thudugala Mudalige K.G. January 2002 (has links)
published_or_final_version / Civil Engineering / Master / Master of Philosophy
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Bivariate distribution of n iid exponential random variables KPQ-EXP /Qeadan, Fares. January 2008 (has links)
Thesis (M.S.)--University of Nevada, Reno, 2008. / "August, 2008." Includes bibliographical references (leaves 88-93). Online version available on the World Wide Web.
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Using radar and hydrologic data to improve forecasts of flash floods in Missouri /Hatter, Elizabeth. January 2004 (has links)
Thesis (M.S.)--University of Missouri-Columbia, 2004. / Typescript. Includes bibliographical references (leaves 63-64). Also available on the Internet.
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Relationships of flow and basin variables on the island of Newfoundland, Canada with a regional application /Richter, Susan, January 1994 (has links)
Thesis (M.Eng.)--Memorial University of Newfoundland. / Typescript. Bibliography: leaves 238-248. Also available online.
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A comparative study of flow forecasting in the Humber River Basin using a deterministic hydrologic model and a dynamic regression statistical model /Picco, Robert C., January 1997 (has links)
Thesis (M. Eng.), Memorial University of Newfoundland, 1998. / Bibliography: leaves 88-90.
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Using radar and hydrologic data to improve forecasts of flash floods in MissouriHatter, Elizabeth. January 2004 (has links)
Thesis (M.S.)--University of Missouri-Columbia, 2004. / Typescript. Includes bibliographical references (leaves 63-64). Also available on the Internet.
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A precipitation model and its use in real-time river flow forecastingGeorgakakos, Konstantine P January 1982 (has links)
Thesis (Sc.D.)--Massachusetts Institute of Technology, Dept. of Civil Engineering, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography: leaves 246-250. / by Konstantine P. Georgakakos. / Sc.D.
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Decision Making Under Uncertainty in Systems HydrologyDavis, Donald Ross 05 1900 (has links)
Design of engineering projects involve a certain
amount of uncertainty. How should design decisions be
taken in face of the uncertainty? What is the most efficient
way of handling the data?
Decision theory can provide useful answers to these
questions. The literature review shows that decision theory
is a fairly well developed decision method, with almost no
application in hydrology. The steps of decision theoretic
analysis are given. They are augmented by the concept of
expected expected opportunity loss, which is developed as a
means of measuring the expected value of additional data before
they are received. The method is applied to the design
of bridge piers and flood levees for Rillito Creek, Pima
County, Arizona. Uncertainty in both the mean and the variance
of the logarithms of the peak flows of Rillito Creek is
taken into account.
Also shown are decision theoretic methods for: 1)
handling secondary data, such as obtained from a regression
relation, 2) evaluating the effect of the use of non -
sufficient statistics, 3) considering alternate models and
4) regionalizing data.It is concluded that decision theory provides a
rational structure for making design decisions and for the
associated data collection and handling problems.
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The impact of climate change on hydrological predictions, with specific reference to 24-hour rainfall intensities in the Western CapeVan Wageningen, Andries 03 1900 (has links)
Thesis (MScEng (Civil Engineering))--University of Stellenbosch, 2006. / The climate of the world varies from one decade to another, and a changing climate is
natural and expected. However there is a well-founded concern that the
unprecedented human industrial development activities of the past two centuries (and
mainly the last century) have caused changes over and above natural variation.
Climate change is the natural cycle through which the earth and its atmosphere are
going to accommodate the change in the amount of energy received from the sun.
There are various indicators that can be monitored to measure and verify possible
climatic changes. This thesis will firstly emphasize what the possible effects of
climate change could be on amongst others, the coastal zone, biodiversity and water
resources. If the impact of climate change on the above mentioned processes are
monitored, and changing trends can be identified, these processes could in fact be
seen as climate change indicators. This is of major importance to us, to be able to
accurately identify whether climatic changes are experienced in any given area and to
attempt to quantify it.
Engineering hydrologists are, amongst other duties, responsible for the determination
of peak discharges to be able to size conduits to safely convey the stormwater for
given recurrence interval events. All hydrological predictions are indirectly or directly
based on historical data. Empirical formulas and deterministic methods were
developed and calibrated from known historical data. Statistical predictions are
directly based on actual data. The question that arises is whether the historical data
still provides an accurate basis from which possible future events can be predicted?
This thesis strives to find an answer to this question and will also try to advise
hydrologists on how they should interpret historical data in the future, taking climate
change into consideration. The methodology that will be followed will be to compare
the percentage of occurrence of 24-hour rainfall events of different magnitudes, for
historical- as well as predicted rainfall, for five different rainfall stations in the
Western Cape. A detailed analysis of measured data at a rainfall station, with 42
years of useable data, will also be performed, to verify whether any measurable trends
have already been experienced. Conclusions shall be drawn as to possible trends, and
recommendations will be made as to how hydrologists could allow for the possible
changing rainfall patterns.
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