This paper presents a modelling exercise for benchmarking the compound channel modelling capability of 1D hydraulic model (MIKE URBAN/MIKE11) by comparing modelling results with that of 2D (MIKE21) and 1D-2D (MIKE11-MIKE21) coupled modelling packages for Oteha Stream catchment under identical network, topographical and boundary conditions.
Storm runoff is usually measured only at the catchment outlet, which restricts hydrological modelling to lumped empirical whole-catchment measures. This defeats physical analysis of the runoff process where the actual catchment has a diversity of permeabilities, slopes and storm intensities.
This presentation highlights the apparent areas of incompatibility between traditional drainage design and LID. It goes on to show that, drawing on experience from around the world and with some innovation in the way we design drainage and with the support of emerging technology, we can get the best of both worlds, maintaining the focus on good stormwater management while putting into practice the sustainable approach of LID. As a result, we should be able to mitigate urban flooding and reduce degradation of water quality in a way that is affordable now and in the future.
This paper covers stormwater control methods, LID treatment devices, hydraulic modelling and urban design principles utilised to produce a subdivision that not only meets legislative requirement but also creates a place we would like to live in.
Low impact stormwater management devices for stormwater treatment are increasingly common elements in the urban landscape around the world. Their use has been suggested as a means of adaptation in areas with projected increases in the intensity and frequency of extreme rainfall. However, there is little advice on how to design these devices for climate change and the costs involved.
Engineered green roofs are becoming prevalent as low impact designs (LIDs) since they offer multiple benefits including stormwater control. Christchurch’s rebuilding plans strongly encourage LIDs including green roof systems but no performance data for these under local conditions are reported. In order to understand the hydrological response, and hence sustainability, of green roofs in Christchurch, different experimental systems were established and monitored for a year at the University of Canterbury.
Christchurch desperately needs new affordable housing for families displaced by the 2010 and 2011 earthquakes. Gravel deposits on the alluvial fans of the large north Canterbury rivers provide attractive building sites in terms of foundation conditions with a low risk of liquefaction. However, the fact they are alluvial fans means that a river has flowed there at some stage in the past. We will present a case study of the flood hazard assessment that was undertaken for an 80 hectare residential development in close proximity to the Cust Main Drain, which in name might sound rather innocuous but in fact has flood flows in excess of 200 m3 /s.
This paper gives an overview of the scheme operation and proposed fishery enhancement measures, its’ role within the wider catchment and the often conflicting issues arising between environmental and economic drivers.
This project integrates many needs including a large motorway project, parks, local community, Iwi, transport and greenways linkage and ecological function. It is one component of a catchment–wide flood mitigation strategy which has been through a BPO approach arriving at a construction project which will make a real difference on the ground. This paper presents Oakley stream widening as an example of the new Auckland Council‟s ability to tackle difficult and complex problems at a large scale.
This paper describes two different methodologies used in producing mapped overland flow paths undertaken for the Auckland region. The methodologies make use of a series of automated Geographic Information System (GIS) tools in ArcGIS 10.
This paper shows the close relationship between predicted flooding from overland flow and actual flooding from the storm affected area and the benefit of mitigation works where they have been already undertaken.
A reconfiguration of the TP10 constructed wetland design has been undertaken to extend detention to 10 days while still maintaining extreme event stormwater attenuation. The reconfigured design was developed during appeal mediation of a granted consent for combined treated wastewater and stormwater disposal. Located in Ruakaka the 6ha wetland, when fully developed, will receive stormwater runoff from up to 180ha mixed land use and 3000m³/day dry weather treated wastewater flows.
Pegasus Lake is a 14 ha manmade lake in Pegasus Town, a new residential and commercial development in Canterbury. The design objectives for the lake were to provide an aesthetically pleasing lake that was suitable as a recreation facility.
In 1998, the Auckland Regional Council (now Auckland Council) initiated a sediment chemistry monitoring programme aimed at assessing the spatial distribution of, and temporal trends in, key chemical contaminants across the region?s urban estuaries, harbours, and sheltered open coast. Over the subsequent 14 years important lessons have been learned concerning factors such as QA procedures and reporting, consistency of methods and the influence of analytical variability.
NIWA is leading the development of an open-access searchable database of New Zealand urban runoff quality data. Data are being collected from organisations such as regional councils, territorial authorities, roading agencies and research institutes throughout New Zealand, many of which hold large datasets of stormwater quality data collected over the last 10 years.
Auckland Council is the result of the combination of eight legacy councils. From ‘Day One’ of amalgamation on 1 November 2010, the Stormwater Operations Group (Stormwater) has focused on continuity of service provision, ensuring minimal disruption while utilising legacy processes, procedures, systems and protocols.
Stormwater Management, Flood Alleviation, Reuse of Abandoned Infrastructure, Watermain, Multifunctional Use of parks, Best Practical OThis paper outlines the design of a stormwater scheme that includes taking one of these constraints – a large diameter abandoned watermain – and turning it into an opportunity that sustainably re uses an asset that was believed redundant. The scheme also includes turning a local reserve into a multi-functional stormwater storage area and using an existing sewer for the attenuated discharge of stormwater. The scheme provides a cost effective and sustainable solution to manage flood risk to residents which can be readily adapted to provide an improved level of service in the future should the opportunity arise.
A sustainable development approach to stormwater management involves taking into account the social, economic, and cultural wellbeing of people and communities as well as maintaining and enhancing the quality of the environment. In order to support this approach, a pilot decision support system (DSS) has been developed which evaluates stormwater management outcomes for receiving water bodies by predicting indicators for the four wellbeings.
In 2006 Beca embarked on a 5-year redevelopment project for the College of the Marshall Islands (CMI) campus in the Republic of the Marshall Islands. A feature of the Masterplan was to achieve a water utility infrastructure on campus that was as self-sufficient from the municipal water supply as possible given the island shortage of water and poor reliability of supply. Rainwater collection and treatment, RO desalination and alternative energy options for the campus were implemented.
This paper outlines how savings can be achieved in operating costs by smarter use of aeration in typical activated sludge process. Various principles and techniques of aeration control are discussed in this paper. The main techniques being feed forward control based on influent and air on/air off method. In the latter, two classes of nitrifying organisms are made to work sequentially thus optimising the utilisation of supplied oxygen. Furthermore, real time oxygen uptake rates of the mixed liquor can be measured, which further assists in process optimisation and control.
The Life Cycle Assessment Manager for Energy Recovery (LCAMER) Tool by Water Environment Research Foundation for on-site energy recovery system (ERS) evaluation using biogas was used. Two case studies are presented, including a FOG facilities. LCAMER is a spreadsheet based model that uses a life cycle assessment approach to compare relative economic benefits of one ERS to another over the life of the system.
UV disinfection has been used without filtration to treat Blenheim’s water supply. The water source could not be shown to be secure and required 3 log Cryptosporidium removal or inactivation to meet the Drinking Water Standards for New Zealand 2005 (revised 2008) (DWSNZ) protozoal compliance. UV disinfection was able to achieve this.