Thesis (M Eng) -- University of South Australia, 1993

[Abstract]: Pollution due to urban stormwater runoff is a significant environmental issue. Large regional devices including sediment ponds and constructed wetlands are common features in the urban landscape to treat runoff. In keeping with this approach, data requirements to evaluate stormwater impacts have mainly been met by the monitoring of sizeable urban catchments, typically greater than 10ha in area. Urban runoff characteristics have thus been conventionally linked with broadly defined catchment attributes. Land use, as defined by zonings such as Residential, Commercial and Industrial, is an attribute often used to evaluate stormwater runoff from urban catchments.The emergence of Water Sensitive Urban Design (WSUD) in Australia is changing the management focus from the reliance on a small number of large-scale devices to many smaller-scale source controls distributed throughout the catchment. This paradigm shift in stormwater management places greater emphasis on small-scale processes within urban areas. Subsequently there is a need for more knowledge about stormwater generated from specific urban surfaces (roads, roofs, grassed areas etc).The objective of this study was to demonstrate how urban stormwater quality can be managed on the basis of urban surfaces. The study involved the collection of data for typical urban surfaces and the development of predictive models to estimate stormwater quality. A series of case studies is provided to illustrate the use of surface-related data and modelling tools in stormwater management, particularly in the context of WSUD.Non-Coarse Particles (NCP), defined as suspended solids less than 500μm in size, was selected as the stormwater pollutant under consideration. NCP is divided into the following particle size classes; Very Fine Particles (VFP, <8μm), Fine Particles (FP, 8-63μm) and Medium Particles (MP, 63-500μm). Laboratory methods to determine the concentration of these particle classes within stormwater runoff were adapted and refined from current standard methods. Organic content of each stormwater particle class was also determined.An innovative device, the flow splitter, was developed to collect runoff samples from urban surfaces. The flow splitter was designed to obtain a composite flow-proportional sample, necessary to derive the Event Mean Concentration of stormwater particles. Hydraulic and sediment testing of a prototype flow splitter confirmed that the device is an accurate and unbiased sampling method.Flow splitters were installed at five monitoring sites within inner city Toowoomba, Australia. The sites have small catchments (50 to 450m2 area) representative of urban impervious areas (galvanized iron roof, concrete carpark and bitumen road pavement) and pervious areas (grassed and exposed bare soil). Overall, runoff from 40 storms with rainfalls from 2.5mm to 64.3mm was sampled during the period December 2004 to January 2006.A scatter plot analysis identified potential correlations between measured NCP loads and basic rainfall parameters such as rainfall depth and intensity. An exponential-type trend, consistent with many washoff models, is evident between load and average rainfall intensity for all surfaces. A composite index, referred to as the Rainfall Detachment Index (RDI), was found to be better than average rainfall intensity in explaining a relationship between NCP load and storm rainfall characteristics.The insight gained from the RDI led to the development of a particle Mass Balance Model for impervious surfaces. Depending on the surface type, the model was able for provide reasonable estimates (R2 = 0.74 to 0.97) against the measured NCP loads. Simpler analytical methods for particle load estimation were also developed in the study. A total of five methods were produced. An error analysis was conducted to compare the performance of each method to accurately reproduce the measured NCP loads. The analysis also included three methods used in current practice, which performed poorly compared to the new modelling techniques.The analytical methods provide useful tools in urban stormwater planning. The Mass Balance Model and measured surface-specific data were used in a number of case study examples to demonstrate possible applications. The applications included assessments of 1) the relative contribution that different urban surfaces make to the particle load in runoff; 2) how surface-specific data can be directly transferred to represent a large-scale urban catchment located in a different climate; 3) the particle loads generated from Residential and Commercial land uses; 4) the effect of exposed areas of bare soil on the particle loads from a Residential catchment; 5) the effect that widespread adoption of rainwater tanks may have on particle concentration in Residential urban runoff and 6) the particle load reductions by the use of a grass swale to treat road runoff.

This study investigated the catchment of an urban wetland on sandy soils in Perth, Western Australia. The wetland is of high conservation value but is currently used as a stormwater-compensating basin. The three main aims of this work were to: 1. determine the importance of stormwater drains in the water and pollutant balance of the lake; 2. evaluate pollutant retention rates by the wetland; and 3. identify current land uses in the catchment, determine their impacts on the wetland and identify tolerable levels of urbanisation for a wetland of this type. Stormwater flowing in and out of the lake subcatchments was monitored for two years for background flows and storm events. Water discharge, physical and chemical characteristics —including nutrients and heavy metals — were measured. Water and pollutant mass balances were determined. There was year-round flow at all sites, except from the smallest subcatchment. Flow characteristics differed between sites and were more influenced by catchment characteristics than rain intensity or duration. More water entered than left the lake in spring. In autumn more water left the lake via the overflow than entered. Due to poor maintenance, many drains overflowed during storm events. When compared to Australian and New Zealand Environment and Conservation Council (ANZECC) water quality guidelines for receiving waters, only pH and conductivity met the recommended criteria. The nutrient and heavy metal loads varied with rainfall during both years of study. Suspended solids, total nitrogen and total phosphorus concentrations were proportional to rainfall, while concentrations of dissolved forms of nutrients were not. Background flows contributed significantly to the pollutant load. More than 85% of total suspended solids, nutrients and heavy metals were retained by the wetland — the only exceptions being copper and some forms of dissolved nutrients. An evaluation of the performance of the lake as a pollutant sink, using published data from constructed wetlands, identified phosphorus as the pollutant that requires the largest area for treatment.

This thesis concerns general improvements to rainfall runoff models and focuses on two particular aspects, namely flood-wave routing in the main channel and consistent parameterisation of the rainfall-runoff process under different degrees of discretization of the catchment. The primary goal is to: 1) describe a general methodology for parameterisation of a rainfall runoff model so that the parameters are consistent across catchments modelled at different discretization scales and 2) develop an improved channel routing technique which takes proper account of the effects of all characteristics of wave motions in the channels. The first of these concerns methods for removing the inconsistency of parameterisation that results from different catchment discretizations in rainfall-runoff models. A stochastic Tokunaga network is developed for dealing with the scaling inconsistence. The problem of network embedding is also discussed. The second is a relatively simple method for the solution of the full dynamic wave equations for one-dimensional channel flow, which accurately simulates the effects of shocks. / PhD Doctorate

Thesis (M.S. - Renewable Natural Resources)--University of Arizona. / Includes bibliographical references.

Thesis (M.S.)--University of North Texas, Aug., 2007. / Title from title page display. Includes bibliographical references.

Diss. (sammanfattning) Umeå : Sveriges lantbruksuniv. / Härtill 6 uppsatser.

Thesis (Ph.D.)--Murdoch University, 2001. / Thesis submitted to the Division of Science and Engineering. Bibliography: leaves 205-222.

Thesis (Ph.D.)--University of Adelaide, Dept. of Civil and Environmental Engineering, 2002. / "May 2002" Includes list of papers published during this study. Errata slip inserted inside back cover of v. 1. Includes bibliographical references (leaves 331-357).

Thesis (M.Sc.). / Written for the Dept. of Bioresource Engineering. Title from title page of PDF (viewed 2008/05/30). Includes bibliographical references.