Many aspects of managing stormwater runoff were investigated for the Town of Blacksburg, Virginia, that would minimize the costly installation and environmentally damaging impacts of storm sewers as the town urbanizes. These aspects included the technical, political, financial, legal, and administrative approaches for controlling runoff at present levels, and for promoting the restoration of streams and preservation of natural drainage ways. The study used a computer model of the town's drainage system to assess the potential of technical approaches for runoff control and stream restoration. The financial and legal ramifications of a storm drainage user fee were explored in depth as a means to finance drainage improvements that rely on natural means for controlling runoff. Recommendations were presented on how to implement these technical, legal, and financial approaches through the town administration and citizen groups. / Master of Urban and Regional Planning

An investigation has been made to determine the effect of geometry on the performance of six collection troughs that served to collect and store grit captured by a model grit chamber. The grit employed was a 0.1mm sand fraction obtained by sieving and the width of the channel of the model grit chamber was 0.5 ft. Over a hundred experiments were performed which spanned a range of velocities of from 0.31 to 1.1 ft/sec and a range of depths of from 0.1 to 0.36 ft. The performance of the grit chamber - collection trough units was evaluated in terms of percentage grit capture under comparable flow conditions and observation of grit travel patterns. The results indicated that the performance of the troughs was influenced by the volume, the depth to length ratio and the slope of the upstream and downstream walls. High performance appeared to be induced by large volumes, moderate depth to length ratio, vertical upstream wall slope, and a downstream slope of 2 vertical to 1 horizontal. / M.S.

A statistical model has been developed to study the long-term behaviour of a stormwater detention unit. This unit stores a portion of the incoming runoff, corresponding to the empty space available in the unit, from which runoff is pumped to a treatment plant. The objective is to avoid, as much as possible, the discharge of untreated runoff to receiving bodies of water. The model was developed by considering the arrival of independent runoff events at the urban catchment. The process variables of event depth, duration, and interevent time were treated as independent, identically distributed random variables. A storage equation was formulated from which the probability of detention unit overflow was obtained. With this distribution it was possible to define the trap efficiency of the unit in terms of the long-term fraction of the runoff volume trapped by the storage unit. The trap efficiency expressions define storage/ treatment isoquants, which represent the combinations of storage capacity, treatment rate, and the sewer system runoff trapping capacity, which provide a fixed level of runoff control. A pollutant load model was also formulated, based on a first-order washoff model. This model was used to define pollutant control isoquants. Optimal values of the required storage capacity and treatment rate were obtained by treating the isoquants as production functions. Applying the results of production function theory, a cost minimization problem was solved for the value of the storage capacity and treatment rate, for prescribed runoff and pollutant trap efficiency levels. The results obtained with the statistical model compared well with results obtained from major simulation models. The statistical approach offers an advantage in that no simulation is required to obtain the isoquants, as the expressions are analytical, thus greatly simplifying the optimization process. Also, the evaluation of the storage unit pollutant trap efficiency can be easily evaluated for any type of pollutant whose washoff rate is known. / Ph. D.

Thesis: M.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1978 / Bibliography : leaves 138-139. / M.S. / M.S. Massachusetts Institute of Technology, Department of Civil Engineering

Sewer flooding incidents in the UK are being increasingly associated with the presence of blockages. Blockages are difficult to deal with as although there are locations where they are more likely to occur, they do occur intermittently. In order to manage sewer blockage pro-actively sewer managers need to be able to identify the location of blockages promptly. Traditional CCTV inspection technologies are slow and relatively expensive so are not well suited to the rapid inspection of a network. This is needed if managers are to be able to address sewer blockages pro-actively. This thesis reports on the development of low-cost, rapidly deployable acoustic base sensor that will be able to survey live sewer pipes. The sensor emits short coded acoustic signals which are reflected from any defects of the wall of the underground pipes and recorded for future processing. The processing algorithms are based on the temporal windowing, deconvolution, Fourier, and intensity analysis so that the response can be linked directly to the location and property of the of the pipe deformation. The sensor was tested in a full scale sewer pipe in the laboratory and in few sites in UK, Austria and Netherlands and it was shown that it is able to discriminate between blockages and structural aspects of a sewer pipe such as a manhole and lateral connection. The anticipated cost is orders of magnitude lower than any current technique.

A project report submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in partial fulfillment of the requirements for the degree of Master of Science in Engineering. Johannesburg, 1997 / Detention storage IS a well tested, and generally accepted, method of attenuating flood hydrographs, but relatively littlo data is available from the monitoring of full scale instc'lations An onstrearn pond was constructed at Sunninqhill Park and details of 15 inflow and outflow hydro [Abbreviated Abstract. Open document to view full version] / MT2016

Owners of infrastructure assets have responsibility for the management of a diverse portfolio of civil engineering assets. These assets make up the foundations of modern society and are arguably pivotal in the economic growth and wellbeing of a nation. It is of no surprise therefore, that asset management business practises have risen in popularity as the UK’s infrastructure asset base continues to grow and inevitably ages with time. In the context of water and waste water infrastructure assets, which communities rely upon for health, economy and environmental sustainability, it is widely acknowledged that these assets have historically suffered from underinvestment. Whilst funding shortfalls have been evidenced historically, through the inadequacy of infrastructure to meet the needs and challenges of the past, it is of great concern that infrastructure expenditure is reducing in real terms as a result of the global financial crisis. This is leading to a widening funding gap between the available and the required finances for infrastructure investment which is further compounded by natural phenomena and human behaviours, i.e., climate change, population growth and urbanisation. To further intensify the problem, asset planning and management in the water industry is considered a complex and challenging discipline because of high interdependencies and the vast quantity of assets themselves. In acknowledgement of this global position, this thesis seeks to address some of the key challenges faced by utility companies in the adoption of asset management best practice across water and waste water assets, namely: • Operational decision making - the efficient and effective specification of least-cost rehabilitation programmes from condition information that ensure behavioural alignment with an organisations strategic objectives. • Tactical decision making - achieving risk based asset level inspection prioritisation that considers serviceability performance, for two particularly challenging asset groups: i.) High value - low volume assets and ii). Low value - high volume buried infrastructure. • Strategic decision making - identifying optimal long-term investment plans and asset management policies for assets that have previously not benefited from such technological advancements. To improve upon operational decision making, the author capitalises on the availability of condition inspection information for buried sewerage infrastructure by applying advanced optimisation techniques to help form an environment where the decision makers is presented with an array of optimal rehabilitation solutions. The trade-off curve that is presented uniquely evaluates solutions for the benefits they offer in-terms of: condition improvement, cost and operational performance. A financially favourable comparison (up to 45% saving) is drawn between the optimisation results which are automatically generated by the model and those that have been developed manually by experienced engineers in a ‘real world’ case study. However, it could be argued that the greatest benefit arises from the trade curve of feasible solutions which are presented to the decision maker across a range of investment levels. In recognition that tactical and strategic decision making have been the focus of a substantial amount of research for commonly found infrastructure assets, i.e., public sewers and water mains, a focus has been placed on improving upon and adopting best practise across infrastructure assets which have not previously benefited from the technological developments across these decision making levels. Firstly, a methodology for translating standardised condition inspection information into more meaningful reliability scores, to support risk based planning and decision making, is presented for service reservoirs. A service reservoir can be regarded as high value- low volume infrastructure asset and would typically have its condition evaluated between 1 (poor) to 5 (good). A case study demonstrates how this new reliability scoring mechanism has been successfully applied during a typical structural condition survey. The output from this process is a fully document reliability assessment for each component of the service reservoir. The output can be aggregated to provide an overall reliability assessment for the structure and/or used to target specific remedial works to troublesome components. Secondly, two methodologies are presented which address the fact that high volume – low value infrastructure assets across both the water distribution and wastewater collection networks, are typically less well understood and often sub-optimally managed in comparison to more critical or higher value assets. 1. A methodology has been developed to help UK water companies overcome the recent legislative changes associated with Section105A of the Water Act; which has transferred ownership of the private sewer network to UK water companies. The new methodology which has been developed, has allowed one of the UK’s water and sewerage companies to initiate a proactive asset management programme with the aim of addressing the deteriorating condition of these assets whilst also tackling their associated serviceability performance. Initially, a number of GIS tools are used to provide an estimate of the likely extent of the transferred network before a well-established public sewer deterioration model is used to predict the condition and operational performance of these S105A assets over time. 2. A novel deterioration modelling framework is developed by coupling the latest geospatial technologies with statistical deterioration modelling techniques. The modelling framework is specifically applied to small diameter water distribution assets (25-50mm diameter), known as communication pipes, which connect individual properties to the water distribution mains. Reliability curves are developed from failure data provided by two UK based Water Companies that have captured specific communication pipe failure records since 2001. The deterioration modelling curves and supporting data are compared and contrasted to demonstrate the robustness of this modelling approach, which is shown to be capable of modelling failure rates to a high degree of accuracy. This was validated by comparing the predicted number of failures against three years of failure data not used during the model building process. The yearly failure counts were predicted to within +/-5% accuracy and the overall cumulative modelled failure count at the end of 2014 was predicted within 1%. To conclude, the successful deterioration modelling tools for communication pipes are explored further, via the development of a strategic whole life cost optimisation framework for these assets. The outputs from the previous geospatial mapping tool are used alongside the calibrated Weibull deterioration curves to drive a whole life cost and performance analysis. Against this improved understanding of whole life costs, an optimisation algorithm is used to evaluate the trade-off between whole life costs (totex) and the prevention of future asset failures (serviceability). The model successfully identifies optimised investment policies according to the decision maker’s priorities which is evidenced in a case study that shows outperformance against existing maintenance policies for these assets. Financial savings in the region of £8.5M, or the prevention of 1,320 asset failures, were shown to be possible over a 25 years planning horizon in the case study. For the avoidance of confusion, the term ‘integrated’ is considered from the perspective of the three decision making levels associated with the management of an asset, namely: strategic, tactical and operational decision making. Therefore, data quality improvements and the management of information transactions between decisional levels are inherently considered within all of the methodologies developed in this thesis.

nÃo hà / A modelagem ambiental à uma importante ferramenta para projetos e estudos envolvendo a gestÃo ambiental, devido à complexidade dos sistemas ambientais. Com ela à possÃvel integrar um grande nÃmero de variÃveis e processos de forma a obter uma visÃo dinÃmica de tais sistemas e avaliar as suas condiÃÃes presentes e futuras. Neste trabalho sÃo apresentados os resultados de modelagens da qualidade bacteriolÃgica da Ãgua da Ãrea costeira de Fortaleza (Brasil), frente a diversas entradas de cargas contaminantes nas mesmas. Coliformes termotolerantes, usados como indicadores de qualidade de Ãguas de banho pelas normas brasileiras, foram numericamente modelados usando o SisBaHiA (Sistema Base de HidrodinÃmica Ambiental), usando-se cargas contaminantes provenientes de trÃs diferentes tipos de fontes: rios, galerias pluviais e emissÃrio submarino. Os modelos foram implementados de forma a representar as variaÃÃes de decaimento frente à radiaÃÃo solar e outros fatores ambientais. Foram obtidos valores relativamente prÃximos entre os resultados modelados e monitorados em campo em diferentes cenÃrios. Os resultados mostraram que as galerias pluviais sÃo as fontes de contaminaÃÃo mais importantes, respondendo por episÃdios de nÃo cumprimento dos padrÃes de qualidade de Ãgua de banho, especialmente durante os perÃodos chuvosos. AlÃm disto, os resultados mostraram nÃo haver riscos da pluma do emissÃrio submarino de Fortaleza alcanÃar as Ãreas de banho das praias da cidade. / The environmental modeling is an important tool for studies and projects involving environmental management, due to the complexity of environmental systems. With it you can integrate a large number of variables and processes in order to obtain a dynamic view of such systems and assess their present and future conditions. This paper presents the results of modeling the bacteriological quality of the water in the coastal area of ​​Fortaleza (Brazil), and against several entries contaminant loads in them. Fecal coliform, used as indicators of quality of bathing waters by Brazilian standards, were numerically modeled using SisBaHiA (System Base Environmental Hydrodynamics), using contaminant loads from three different sources: rivers, storm sewer and outfall . The models were implemented to represent the changes in decay forward to solar radiation and other environmental factors. Values ​​were relatively close results between modeled and monitored in the field in different scenarios. The results showed that the storm sewers are the most important sources of pollution, accounting for episodes of non-compliance with water quality standards for bathing, especially during rainy periods. Moreover, the results showed no risk of the outfall plume reaching Fortaleza bath areas the city beaches. .

As local authorities are becoming more interested in the assessment of pollutant loads, this study offers a Geographic Information System (GIS) model for assessing nonpoint source of pollution for two scenarios: the current and ultimate stage of urbanization. The Puhinui Catchment, Manukau City, has been used as a case study in developing and testing this model. This catchment has all the attributes of a "typical" urban area and gives a good representation of the effects of land use on the receiving waters of Puhinui Stream and its estuary. Annual mass contaminant loadings were calculated by firstly assessing the physical characteristics of the Puhinui catchment (case study catchment) and secondly describing the nature of storm water quality and calculating the annual mass contaminant loadings.GIS is used to multiply the annual runoff volume by a mean pollutant concentration to acquire an average annual pollutant load. The annual runoff volume is calculated from the drainage area, runoff coefficient and annual rainfall. To calculate the total mean pollutant load, the pollutant loads for all land use types within the catchment are summed and the process is applied for each pollutant. This GIS model determines the connection of typical pollutant concentrations with land uses in the catchment and offers a characterisation of nonpoint source pollution in that catchment. This model can be used for, identifying catchment areas that contribute considerably to the pollution of waterways, determining the appropriate treatment of the storm water runoff for particular sub catchment, storm water quality improvement prioritization and cost-benefit analysis, selecting locations for water-quality monitoring stations, improvement in maintenance practices, assessment of proposed development environmental effects.

A major upgrade to the wastewater treatment plant in Saskatoon, Canada significantly improved the final effluent quality. Consequently, the relative impact of the citys urban runoff on the receiving stream, the South Saskatchewan River, has increased. Moreover, at the inception of the study, pending amendments to provincial legislation governing urban runoff were such that urban runoff would no longer be automatically exempt from regulation. In response to this impending change, which has since been made, Saskatchewan Environment initiated a study to examine the water quality of the urban runoff in Saskatoon, because little had been done to date involving the water quality of urban runoff in Saskatchewan.<p>The field program was conducted in 2001 and 2002 to collect representative urban runoff water quality and flow rate data from four different land uses: newer residential, older residential, commercial, and industrial. Three characterizations of the water quality were developed on the basis of the data collected: Site Mean Concentration (SMC), multiple variable regression models, and the unit load. The SMC results indicate that the average water quality parameter concentrations in Saskatoon are greater than those from NURP, the updated U.S. nationwide urban runoff database, and from Vancouver, Canada, but are similar to those from Wisconsin. The regression analyses indicate that the rainfall depth is the most frequently significant parameter in the prediction of event loads. The unit load analyses indicate that the commercial catchment produces the most pollutant load per unit area. Comparison of the methods indicates that the SMC can be used to estimate longer term urban runoff loads, in lieu of the more complex regression method.<p>Heavy metals, pesticides, and fecal coliforms were detected in the urban runoff at concentrations that exceed guideline values. Further investigation is recommended.<p>In comparison to the loads discharged by local point sources, urban runoff contributes larger total suspended solids (TSS) and total Kjeldahl nitrogen (TKN) loads to the South Saskatchewan River. The load of COD to the river is comparable to that of the Saskatoon Wastewater Treatment Plant (WWTP). The total phosphorus load contributed by urban runoff is slightly smaller than that of the WWTP. Considering the relative load of TSS from urban runoff to the WWTP and the potential for other, more toxic pollutants to adsorb to the TSS, sediment controls should be implemented at all levels of development. Further examination of urban runoff with specific emphasis on spring and winter runoff is recommended.