• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 72
  • 35
  • 19
  • 5
  • 4
  • 3
  • 2
  • 1
  • Tagged with
  • 194
  • 194
  • 66
  • 53
  • 52
  • 46
  • 43
  • 34
  • 30
  • 27
  • 24
  • 24
  • 23
  • 23
  • 23
  • 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

Legal Support for a Resilient Stormwater Management : Review of Swedish Regulations and Objectives

Aderklint, Denice January 2017 (has links)
Sustainability entails a system that has the capacity to sustain itself. Stormwater management is one part of the concept sustainable development but traditional practices entail adverse effects on social-ecological systems and there is a need for increasing the resilience of urban stormwater systems.  The growing pressure from climate change and intensified urbanization increase the need for stormwater management. If poorly managed the security and functioning of societies will be negatively affected. Regulations are essential in the achievement of sustainable urban environments. However, national regulations concerning stormwater management are spread through different legal frameworks from different times and it has been recognized that the spread could challenge implementation of the regulations and climate change adaptation. Administrative instruments are important to support the social, economic and ecological value of green and blue structures. The thesis target to analyze relevant regulations and investigate their effectiveness for a sustainable stormwater management through combined interpretation methods based on the intention behind the law and their function in society. The thesis claims that consequences of poorly regulated sustainable stormwater management results in an inefficient use of resources and pose a risk for the environment. Sustainable development is not visible in any article in the Law on General Water Services and it therefore risk to be overlooked in practice. The issues of urban stormwater need to be more integrated in the municipal work and planning processes. The analysis reveals that there is support for resilient stormwater management when there is a combination of up-to date research and an objective teleological interpretation. As the shift towards sustainable urban environments entails several aspects, the use of administrative instruments is one important strategy in ensuring urban resilience.
32

Riverfront remediation: redevelopment for human access and wildlife health

Swehla, Tyler January 1900 (has links)
Master of Landscape Architecture / Department of Landscape Architecture/Regional and Community Planning / Alpa Nawre / Historically, industrial riverfronts often polluted waters and sites with chemicals, leading to degraded ecosystem health and reduced numbers of aquatic wildlife downstream. These sites currently pollute the environment through residual chemicals and waste left behind by industrial-era production factories. Urban riverfront redevelopment offers many possibilities to restore wetland ecosystems and reestablish site connections to surroundings through human access. By redeveloping urban rivers for wetland protection and stormwater management, cities can begin to regain their connections with the landscape while providing resilient ecosystems through restoration. This proposal identifies possibilities for riverfront redevelopment as wetlands and tools for restorative action aiding increased human access and wildlife health. A stormwater management plan utilizing phytotechnology is proposed for the ARMCO Site at 7000 Winner Rd. Kansas City, MO, a former steel manufacturing site, adjacent to the Missouri River and Blue River waterways. Using plant material and landscape design, the ARMCO riverfront has been redesigned to unlock the full potential of treatment wetlands and showcase emerging treatment methods that could soon become typical cleanup procedure. A template for remediation design has been created with the techniques identified for remediation, stormwater treatment, and habitat creation outlined in the master plan proposal. Nine precedent studies have been used to identify key concepts for design phasing aimed at human accessibility and modifications of restorative tools. Careful deliberation of stormwater containment and flood plain levels define site layout while contributing design responses adaptable for year-round functionality coupled with landscape interest for each season. The techniques and planting palette have been tailored to address the specific site contaminants for the Missouri River riverfront but are adaptable for various contaminants and ecosystems.
33

Applying the RUSLE and SEDD Equations to an Agricultural Watershed in Southwest Virginia - A Case Study in Sediment Yield Estimation Using GIS

Lally, Lindsay Backus 12 June 2013 (has links)
The goal of this study is to develop a model using GIS to estimate the source and quantity of accumulated sediment in the Emory & Henry College (EHC) duck pond.  Located in the Highlands of Southwest Virginia, the 1,194 acre duck pond watershed consists primarily of agricultural, forested, and low density urban land uses. The Revised Universal Soil Loss Equation (RUSLE) and the Sediment Distributed Delivery (SEDD) prediction models were used to determine the quantity of eroded sediment and the sediment yield at the duck pond, respectively.  These models require numerous computations, which were performed at the watershed scale with the aid of ArcGIS software.  In ArcGIS the watershed was broken into a raster grid of approximately 5,200 discrete 100 foot by 100 foot grid cells. The resulting watershed erosion model identified two main sources of sediment: a cluster of farms relatively close to and east of the duck pond, and a harvested timber site north of the duck pond.  The model predicted that 1,076 tons of sediment are delivered into the duck pond annually. The estimated sediment yield was then compared to the estimated amount deposited between October 2011 and September 2012, as measured by a topographic survey.  The model prediction was found to be within a factor of 6.3x of the measured value.  The predicted and measured sediment yields as well as identified erosion sources can be used to develop a water quality improvement plan and to help alleviate the need for periodic dredging. / Master of Science
34

The Effect of Slope and Media Depth on Growth Performance of Sedum Species in a Green Roof System in Mississippi's Sub-Tropical Climate

Kordon, Sinan 11 August 2012 (has links)
In recent years, green roofs have become an accepted solution in ecological urban design to mitigate the impacts of impervious surfaces (Berghage, Beattie, Jarrett, Thuring, & Razaei, 2009). An experimental research project was conducted at the Mississippi Agriculture and Forestry Experiment Station (MAFES) Green Infrastructure Research Area at South Farm of Mississippi State University to determine how medium depth and slope gradient on rooftops affect plant cover and survival. Plant cover was monitored monthly by photographing the experimental green roof platforms. Photoshop and AutoCAD software programs were employed to digitize and to calculate plant cover from the images. All recorded data was analyzed with Analysis of Variance (ANOVA) tests. It was determined that the effects of medium depth and slope are statistically significant on plant cover and survival.
35

Rainwater harvesting: An assessment of the future potential in Sweden. / Regnvattenåteranvändning: En utverdering av framtida potential i Sverige.

Jensen Wennberg, Anton January 2018 (has links)
The thesis address the field of stormwater management. With a changing climate, the field of stormwater management much like many other fields will need to incorporate sustainable development if overall sustainability is to be reached. The aim of the thesis is to evaluate the current method for dealing with stormwater in Sweden, mainly in urban areas, and point to issues at hand and identified ways of addressing them. The concept of Rainwater Harvesting (RWH) is assessed. A comparison of results from several case studies from around the world show that there are several aspects of high importance for the viability of such technology. Among others price for municipal water, ability to lower costs due to smart planning ahead of installing, inclusion of environmental aspects and impacts on society such as reduced load on water, wastewater and stormwater infrastructure, reduced pollution load and greenhouse gas emissions (mainly due to less water treated at wastewater treatment facilities). The main conclusion from comparing and compiling results were that the viability of RWH from an economic standpoint is questionable. Although if including all identified gains for the municipality including stormwater management benefits and indirect gains due to reduced load and taking all aspects of importance into consideration there is potential for such technology even in a country like Sweden with good water supply and infrastructure in place. This thesis is of importance since it brings RWH technology into the light as a potential sustainability measure in Sweden. It evaluates the important parameters for the technology to be viable as indicated by case studies and literature within the field. / Detta examensarbete behandlar hållbar dagvattenhantering och specifikt tekniken Rainwater harvesting. Nuvarande centrala system för att förse Stockholm med färskvatten samt hantera bildat dagvatten utvärderas i en litteraturstudie. Även identifierade metoder för att hantera dagvattnet i linje med hållbarhetsmål beskrivs. Tekniken Rainwater harvesting beskrivs, dess historia samt implementering i moderna sammanhang framställs. Flertalet fallstudier där tekniken beskrivs analyseras och jämförs. Detta examensarbete är av vikt eftersom det tar upp tekniken RWH i relation till Sverige som potentiellt lokalt system för att uppnå hållbarhet. Det utvärderar viktiga parametrar för att tekniken ska anses försvarbar vilka indikeras av flertalet fallstudier samt litteratur. Dagens system för hantering av dagvatten i Stockholm består till allra största grad av det centrala avloppssystemet bestående av kombinerat samt duplikat avloppsnät. Detta har likt många centrala infrastruktursystem nackdelen att det är kostsamt och besvärligt att uppdatera och stärka, men dessutom flertalet nackdelar relaterade till miljöpåverkan och hög belastning på reningsverk. Rainwater harvesting är en teknik med lång historia som i moderna samhällen implementeras i syfte att minska vattenanvändningen samt belastningen på centralt dagvattensystem. Blandade ekonomiska resultat har observerats, sannolikt på grund av varierande analysmetoder och varierande inkludering av viktiga parametrar i bedömningar. Miljönyttan är till viss del tydlig, dock i många fall ej medtagen i beräkningar och utvärderingar. Analys av fallstudier påvisar hög potential för tekniken vid smart implementering men att det även finns goda exempel på system som resulterat i mycket dåliga ekonomiska resultat. Flertalet viktiga aspekter att ta hänsyn till för att uppnå försvarbara resultat har identifierats och beskrivits. Huvudslutsatsen är att Rainwater harvesting i och med sin potential att nå eller jobba mot definierade mål för dagvattenhantering och hållbar utveckling bör has med i åtanke som potentiellt lokalt system i Sverige kommande år.
36

Turbidity Removal Efficiency And Toxicity Issues Associated With The Chitosan-based Dual Bio-polymer Systems

Hernandez, Rylee 01 January 2012 (has links)
Stormwater runoff can be a great concern in the State of Florida due to the impact the quality of the runoff water can have on the natural water bodies. Stormwater runoff can carry pollutants and sediments which can cause both physical and biological risks in an aquatic ecosystem such as a lake, river, or pond. Polymers, namely the chitosan-based dual polymer system, can be used remove the sediment from this runoff to ensure the safety of the state’s water bodies. Three soils are used in this testing: AASTO soil classifications A-3(sandy soil) and A-2- 4 (silty-sand), and a soil with a fine-grained limerock component. An optimum dose of the chitosan-based dual polymer system is first determined using jar testing. The optimum dose is the dose that reduces the final turbidity to 29 NTUS or below and creates significant flocs. The under dose and over dose are calculated based on the optimum dose. Using these dosages, field scale tests are conducted using two different treatment methods: a semi-passive treatment method and a passive treatment method. Whole effluent toxicity and residual chitosan tests are then conducted on the effluent from the field scale treatment methods. The passive treatment method is the best field scale treatment method when using the silty-sand and the soil with a fine-grained limerock component. The semi-passive treatment method is the best field scale treatment method when using the sandy soil. The passive treatment method with the silty-sand achieves a final turbidity of 123.9 NTUS (88.45% removal). The passive treatment method with the soil with a fine-grained limerock component achieves a final turbidity of 132 NTUS (83.86% removal). The semi-passive treatment method with the sandy soil achieves a final turbidity of 31.43 NTUS (82.04% removal). There is only significant toxicity associated with the tests using iv the effluent from the passive treatment method with the soil with a fine-grained limerock component which only uses the cationic polymer
37

Thermal Pollution Mitigation in Cold Water Stream Watersheds Using Bioretention

Long, Daniel Lewis 24 March 2011 (has links)
This study examines the use of bioretention as a strategy to reduce the thermal impact associated with urban stormwater runoff in developing cold water stream watersheds. Temperature and flow data were collected during ten controlled trials at a bioretention facility located in Blacksburg, Virginia. It was determined that bioretention has the ability to reduce the temperature of thermally charged stormwater runoff received from an asphalt surface. Significant reductions in average and peak temperatures were observed. However, this facility was unable to consistently reduce the temperature below the threshold for trout health. The ability of bioretention to reduce runoff flow rates could also serve to reduce the thermal impact. Based on these results it was concluded that bioretention appears to have the capability to reduce the thermal impact of urban stormwater runoff on cold water stream ecosystems. / Master of Science
38

Development of Effective Procedures for Stormwater Thermal Pollution Potential Risk Mapping

Martin, Clinton James 02 February 2017 (has links)
Thermal pollution of waterbodies occurring from heated stormwater runoff in urban catchments is a growing concern among municipalities in the United States. The U.S. Environmental Protection Agency (EPA) maintains regulatory criteria for temperature of waters of the U.S. as many species of aquatic life depend on an environment that maintains water temperatures below a certain threshold. Thermal pollution from urban stormwater runoff threatens the livelihoods of cold-water fish species, like trout, among other species of wildlife. In order to reduce thermal pollution loading to its streams, a municipality or regulatory authority must first identify the sources of thermal pollution in its waterbodies. This study predicts areas within an urban watershed in the Town of Blacksburg, VA that may be sources of thermal pollution in stormwater runoff by investigating indicators of thermal pollution potential (TPP) through and analysis of land cover types and runoff flow patterns in a geographic information system (GIS) environment. Results of the study provide a theoretical foundation for TPP risk mapping with recommendations for authorities interested in pursuing TPP risk mapping as a tool to guide and focus efforts toward reduction of thermal pollution and land planning. / Master of Science
39

The Impact of Different Stormwater Fee Types: A Case Study of Two Municipalities in Virginia

Dritschel, Amanda Marie 20 June 2016 (has links)
Stormwater user fees (SUFs) are an increasingly popular method of generating revenue for municipalities responsible for implementing complex stormwater regulations through the NPDES permit program. These fees can be created in a multitude of ways, including a flat fee for each parcel, charging by parcel area, charging based on a runoff factor, and many others. As a case study, eight SUFs were applied to the City of Roanoke and the Town of Blacksburg, both in Virginia, to determine the effect each SUF has on how land use type impacts the revenue composition. The City of Roanoke is larger and includes more industrial areas, but less multifamily impervious areas than Blacksburg, which translates differently in the SUFs. Residential parcels comprise the highest percentage of the revenue in all eight SUFs in Blacksburg and four in Roanoke. Open space parcels don't contain much impervious area yet account for up to 27% of the revenue. Industrial parcels comprise more of the revenue in Roanoke, averaging 11.1% compared to 4.6% in Blacksburg. A detailed digitized land cover dataset was compared to Blacksburg's land cover dataset, which resulted in maximum difference of $0.02 per parcel for residential parcel fees. Exemptions of large parcels in Roanoke, like the railroad and airport, if enacted would result in a maximum increase in fees of 15% and a shift of $7,491 of the monthly revenue to the residential parcels. / Master of Science
40

Engineered biochar and EAF slag for the removal of phosphorus from stormwater runoff

Johnson, James Casey 25 November 2020 (has links)
Phosphorus (P) in stormwater runoff has detrimental effects on water quality and ecosystem health when it reaches surface waters and promotes algal blooms. Constructed wetlands (CWs) have been utilized to combat this problem by containing stormwater and removing excess nutrients. Including filter materials in the design of CWs has shown promise for increasing their capacity for nutrient removal. This mesocosm scale study was conducted outdoors over a 12-month period to evaluate the effectiveness of three filter materials in their ability to adsorb phosphorus, retain water, and support plant life. The filter materials examined were electric arc furnace (EAF) slag, engineered biochar, and sand. All treatments demonstrated positive plant response and the ability to retain water. The EAF slag and biochar removed significant amounts of P from effluent and appear to be suitable materials for integrating into CW design. Sand was found to be ineffective as a P filter.

Page generated in 0.1282 seconds