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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Design with stormwater : landscape of integrated LID in Chinese high-density residential development

Du, Shi, 杜實 January 2012 (has links)
Stormwater flooding problems become more and more serious in China recently. Besides the effects of global warming, the deficiency of conventional storm drain system can’t be neglected. This thesis is aiming to analyze the potential problems of existing municipal drainage infrastructure, introduce a more advanced alternative -- Low Impact Development (LID) to deal with urban stormwater management in residential development, which is a soft approach favoring natural way of treatment. LID as a solution not only reduce the pressure in drainage pipes during flood peak, but can also supplement underground water ecologically, which could positively protect precious water resources in China. Since urbanization is extremely rapid in China, if not understanding the fundamental reason, solely depending on increasing the diameters of drainage pipes will never catch up the speed of runoff that generated by impervious area, which resulting from more and more surface runoff being circulated and centralized to the storm drain system in a shorter and shorter time. The objective of this thesis is to let authority and public recognize the fundamental reason of this problem and at the same time realize the benefits of LID. Moreover, provide a residential landscape design that integrated LID within Chinese specific urban context as an alternative. / published_or_final_version / Architecture / Master / Master of Landscape Architecture
32

A Case Study of Dry Well Recharge

Wilson, L. Graham 09 1900 (has links)
A case study of dry well recharge / Research Project Technical Completion Report (A-114-ARIZ) / Prepared for the U.S. Department of Interior / September 1983.
33

Control of urban runoff through the use of permeable pavements

Berry, Carmel Therese January 1995 (has links)
In order to control stormwater runoff engineers and hydrologists have used various techniques to attempt to reduce or delay the volume of water which reaches the sewer system. Recently, international approaches have favoured the idea of "source control" or "on-site" retention. This technique stores water in areas close to the point at which precipitation lands. Permeable pavements and similar stormwater control devices have not been exploited in the United Kingdom. Their adoption has been hindered by a lack of knowledge of their hydrological performance. This research aims to produce information on the hydrological performance of a car park surface and to produce a model which can predict the hydrological response to varying rainfall inputs. The objective of this thesis is to examine the hydrological behaviour of a model car park surface under varying rainfall conditions. The study has involved the construction of full-scale permeable pavement model car park structures and a rainfall simulator for use in the laboratory. A monitoring procedure was developed in order to measure inputs and changes in drainage, storage and evaporation over short (less than 2 hours) and long (up to 3 months) time scales. A range of rainfall simulations were applied to the model car park surfaces which differed in intensity, duration and volume. Hydrological processes were monitored over an 18 month period. Results suggest that evaporation, discharge and retention in the structures were strongly influenced by the particle size of the bedding material and the surface blocks. In general an average of 55% of a 15 mm 11-1 rainfall event could be retained by an initially dry structure. Subsequent simulations suggest that approximately 30% of a 15 mm rainfall event could be stored by an initially wet structure (with a minimum time interval of 72 hours). Sediments were also applied to the car park structures in order to monitor the effects of clogging on hydrological performance and to quantify the ability of the structures to act as a primary screening site for sediments. The application of sediments to the structure showed that evaporation from the structure increased by as much as 25-30%. Laboratory simulation of clogging effects was also compared to data gathered from field sites and the results suggested that laboratory simulations provided a good approximation of the migration of sediments in the structure. A model of the hydrological performance of the structure has been developed to be used as a predictive tool. The model relates rainfall inputs to water retention and discharge output over consecutive rainfall events. It also allows evaporation and long-term retention by the structure to be estimated over differing lengths of dry periods. The model results indicate that discharge was predicted to an accuracy of 78% (based on a percentage difference between the observed and predicted values), and evaporation and retention were predicted to an accuracy of 80%.
34

Optimal policies for storage of urban storm water /

Piantadosi, Julia Unknown Date (has links)
Water management is a critical issue around the world. In South Australia, and throughout Australia, demand for water has increased beyond the capacity of existing water supply systems. For this reason there is great interest in optimal management of water resources at both a national and local level. / In this thesis I discuss the capture and treatment of urban stormwater and suggest practical strategies for water storage in a sequence of dams. My primary motivation was a proposal for the capture, treatment and storage of all stormwater and wastewater on a new suburban housing estate at Mawson Lakes in South Australia, while minimising overflow. / A discrete state mathematical model for the management of water in a system of two connected dams is described in detail, through the use of stochastic matrices. I assume random inputs and regular demand. The system is controlled by pumping water from the first to the second dam. Only practical policies are considered. My initial analysis was restricted to a class of policies that depends only on the content of the first dam. The steady state of the system can be determined for each particular control policy. To determine the steady state I have used Gaussian elimination to reduce the problem of solving a large set of linear equations to a much smaller set. The steady state is an invariant measure that determines the long-term expected overflow. The systematic state reduction procedure subsequently allowed me to consider more complex policies that depend on the content of both dams. One such policy that I analyse in detail is to pump to fill the second dam. Though it is not yet proven this policy is possibly the optimal policy from among the classes considered. I also extend the discrete state model to a system of two connected dams with continuous input into the first dam. The stochastic matrices are replaced by integral operators on a space of bounded probability measures. / An alternative general analysis is described for the policy of pumping to fill the second dam. By using the characteristic pattern of the steady state equations I can define new variables and equations to reduce the problem to a much smaller system of equations. This method was also applied to policies in which I overfill or underfill the second dam. All three solutions are closely related. Yet another method uses a set of superstates. Each superstate is a set of states for which the particular control policy defines a common outcome. Once again the invariant measure is found by solving a reduced order matrix equation. I have also illustrated this method in a particular example. It is entirely possible that my various solution methodologies can be directly related. Although no analysis has yet been done further research into general reduction procedures would be certainly worthwhile. / For each class of controls a computer simulation was used to confirm the theoretical results. The simulation of the two dam system was extended to a system with many dams that is similar to the one proposed at Mawson Lakes. Future investigations include the development of mathematical models and theoretical solutions for the recently revised stormwater storage system at Mawson Lakes. / Thesis (PhDMathematics)--University of South Australia, 2004.
35

Performance and behaviour of on-site retention/overflow wells in Adelaide metropolitan area /

Somaratne, Narayana M. Unknown Date (has links)
Thesis (Master of Engineering)--University of South Australia, 1991
36

Chemical relationships in waters and sediments of some urban streams, with particular reference to heavy metals and phosphorus

Hayes, Warwick Jay January 1996 (has links)
This thesis describes two studies of the chemistry of freshwater streams in the Sydney basin. The first was a survey of 86 waterways, sampled under low conditions. Samples were generally low in salinity, soft, of poor buffering capacity and dominated by sodium and chloride. C0-dominance by calcium, magnesium and (bi)carbonate occured in a number of particular cases. Multivariate analyses indicated three groups, separated primarily by levels of dissolved nutrients, trace metals, turbidity and colour. Groupings were associated strongly with the type of catchment. Streams in areas relatively unaffected by human influence had notable uniformity in chemistry, while those from developed catchments were varied. Heavy metal contamination was relatavely low, although a few of the samples displayed inordinately large levels of one or more metals. In such cases the more extreme measurements of phosphorus and nitrogen were also seen. The findings were consistant with occasional or localised elevation of contaminant levels. The second study invloved monitoring of three Hawkesbury Sandstone streams. Sampling of surface waters, interstial waters and sediments was performing at irregular intervals over a two year period at three stations within each site. The streams predominantly existed under low conditions and showed similar major ion chemistries to the majority of the survey samples. Levels of calcium and total carbonate, plus heavy metals and nutrients were generally higher in the urbanised creeks, comapred to the reference strema. During a heavy storm, high levels of nutrients, suspended solids and colour were detected in all surface waters at peak-flow, as well as alkaline pH, oxidising redox, and reduced conductivity, alkalinity and hardness. The sandy sediments were characterised by very low levels of organic matter and cation exchange capacity. Sequential extractions identified that the sums of secondary phase lead, zinc and copper were over nine, four and two times that of the corresponding residual, respectively. Greatest proportions of zinc and lead were associated with coatings of iron and maganese oxides, or coarse waste particles. Copper was preferentially associated with organic matter. Concentration gradients between interstitial and surface waters were rare and release of sedimentary constituents should occur from the upper-most particulates. Poor water and sediment qualities were often observed in the urban sites. Poor water quality was also seen on occassion in the reference stream. However, since poor sediment quality was not detected at those times and interstitial waters for all sites displayed high within-site variability, surface waters were considered the most reliable short-term indicator of condition for Hawkesbury Sandstone streams. Multidimensional scaling showed that all streams had distinct water and sediment chemistries. High levels of temporal and spatial variability were apparant within the urbanised sites - particularly in interstitial waters - mostly due to concentrations of heavy metals, phosphorus and suspended solids. Seasonal differences were detected, but only in terms of the level of variability between summer and winter samples.
37

Application and verification of several rainfall-runoff models in Hawaii

Murashige, Jo Ann Emi. January 1983 (has links) (PDF)
Thesis (M.S. - Hydrology)--University of Arizona, 1983. / Includes bibliographical references (leaves 113-115).
38

Analysis of biofiltration efficiency for treating stormwater runoff from a parking facility /

Koranchie-Boah, Peter. January 2008 (has links)
Thesis (M.S.)--Youngstown State University, 2008. / Includes bibliographical references (leaves 67-70). Also available via the World Wide Web in PDF format.
39

Development and application of a coupled SWMM-MODFLOW model for an urban wetland

Yergeau, Steven E. January 2010 (has links)
Thesis (Ph. D.)--Rutgers University, 2010. / "Graduate Program in Environmental Sciences." Includes bibliographical references (p. 190-202).
40

Effect of compaction on removal efficiency of lead, copper, zinc, nitrate, and phosphate in a bioretention system a column study.

Moore, James R. January 2008 (has links)
Thesis (M.S.)--Rutgers University, 2008. / "Graduate Program in Environmental Sciences." Includes bibliographical references (p. 55-65).

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