This paper outlines the investigations of earthquake damage, the strategy for “quick fix” repairs to restore plant function, and decisions on permanent repair priorities and methods.
Without the clarifiers in operation the City of Christchurch was exposed to environmental and health risks from the discharge. This created urgency to implement temporary repair on at least 2 clarifiers. The paper describes how a temporary “quick fix” was successfully implemented within 4 months to restore basic plant function.
This paper presents how the methodology has been developed and applied to the evaluation of wastewater rebuild options and other asset rebuild decisions. The paper examines how the methodology has been refined as SCIRT’s focus has shifted from highly damaged areas to other areas that have sustained less earthquake damage, and how the evaluation of options has changed as the rebuild has shifted from a response to a rebuild, with a significant emphasis on returning levels of service across the city.
The present paper critically assesses that analysis and, as a result thereof, identifies serious concerns with the reliability of those conclusions. Furthermore, the present paper examines the temporal trends for zinc in freshwater streams using data obtained from Auckland Council. It is concluded that where statistically significant trends occur for zinc levels in streams, estuaries and harbours, they are mostly observed to be reducing.
The development of the new City Waters Maintenance Contract was an important project in 2011/2012. The Contract’s budget exceeds $5million per year and would be a 4 year performance based contract with extensions up to 4 years.
This paper provides an overview of the multiple case histories of the Direct Pipe technology worldwide, thereby illustrating the benefits for the owner, engineer and contractor in comparison to HDD in permeable soil conditions.
Trenchless rehabilitation techniques can have a lower cost and cause substantially less disruption to existing assets and the general population than conventional ‘open cut’ techniques.
The winning entry in the 2013 Auckland Council Low Impact Design (LID) Competition makes recommendations for stormwater management on and around the Whangaparaoa Golf Course (WGC). Currently, runoff from the surrounding residential area drains through drainage ditches across the course to ponds and wetlands. Perimeter ditches on the WGC were converted to engineered swales and a bioswale to safely convey a 100-yr 24-hr storm event.
This paper will explore the synergies between the local board governance, the technical expertise of Council staff, and implementation through various mechanisms, from contractor to community and school groups. Observations and lessons learned will be shared.
The paper explores the decision processes in selecting the most adequate rehabilitation method. It describes the investigation, design and construction challenges, the strategies used to manage the risks and the approach ultimately utilised for this unique project.
This paper documents the biophysical process assessed in the Barbados Wetland and the ecological, morphological and hydraulic design components used to develop detailed design. This includes discussion of the design process, key elements and research outcomes that informed the final detailed design. The Barbados Wetland Enhancement project is award winning and is an excellent example of a multi-disciplinary approach to erosion remediation works and wetland enhancement.
This paper summarises the common but important aspects needing to be carefully considered in the design, construction and maintenance of the following types of inlets and outlets; catchpits, inlets from open watercourses to pipe networks, inlets and outlets of stormwater treatment devices, stream outlets and beach outlets. The aim is for inlet and outlet related flooding, erosion, maintenance and amenity problems to be avoided in the future.
The majority of Christchurch’s stormwater has historically been discharged untreated directly into urban surface waterways. These receiving waterways have become adversely affected by the contaminants carried in the stormwater, particularly sediment and heavy metals. An event-based contaminant load model was developed to identify the distribution and magnitude of contaminant loads entering the waterway, as well as to assess the reduction in TSS and heavy metal loads that can be achieved by various stormwater management options.
The Christchurch suburb of New Brighton is bounded by the Pacific Ocean to the east and the Avon River/Ōtakaro and Avon-Heathcote Estuary/Ihutai to the west. It drains towards the lower Avon River and the Estuary, both tidally influenced. During the Canterbury earthquakes, the area suffered from liquefaction, land settlement (up to 600mm) and lateral spreading. Some areas are now very low-lying relative to extreme high tides. This creates significant challenges to restoring the stormwater drainage performance.
Overland flow paths and depression areas have been mapped for 17 catchments in Wellington City. Overland flow paths represent the predicted path of stormwater as it flows over the topography. They can be mapped using specialist GIS software and LiDAR data.
The recently constructed Williams Landing railway station provides a new transport node for the rapidly developing western suburbs of Melbourne. It was designed based on providing state of the art safety and environmental benefits to the community. Management and treatment of stormwater runoff generated from the newly built car park is a major challenge due to the flat nature of the area, additional runoff from an air force base and increased flooding impacts on existing railway tracks, downstream properties and the existing railway culvert crossings. In addition to that, stormwater runoff should be treated to meet the Melbourne Water quality guidelines.
Auckland Council is responsible for the development and operation of a stormwater network across the region. Within this stormwater network, aquatic vegetation (including plants, unicellular and filamentous algae) can have both a positive and negative role in stormwater management and water quality treatment, as well as impact on passive and active amenity. The situations where management is needed to control aquatic vegetation are not always clear, and an inability to identify effective, feasible and economical control options may constrain management initiatives.
In this paper the background to the flood risk management framework is detailed, and the framework itself (which is a living document that evolves with time) is presented. The results of the pilot studies are presented and it is hoped that the experience gained during these processes can be applied by others.
The eastern Christchurch catchments of New Brighton, Bridge Street and Southshore total approximately 600ha. Understanding and managing these stormwater catchments is complex with low lying areas, tidal boundaries, and relatively flat grades. This complexity has increased following the Canterbury earthquakes.
This paper outlines the design objectives on which the research was based. These objectives inform how living roof performance may differ when they are not primarily designed for stormwater mitigation, and how to enhance their performance.
Historically, Lake Tangonge was one of the most important mahinga kai of the Te Hiku o Te Ika iwi providing abundant aquatic and dry crop food resources. Tangonge is now a wetland system in a peat basin overlying sand substrate, fed by artesian sources, local catchments and the Awanui River, near Kaitaia, Northland, New Zealand.
This paper will review the basis of pipe structural and installation design, installation methods and practices, and the type and sources of load on SRCP. Crack orientation is another important factor that evaluators need to understand; the paper will detail types and possible causes of each crack type.