This paper outlines the interpretation process followed by the team for the ICMPs, how the model results were reviewed and translated, and how the client/consultant relationship impacted on the outcomes of the project.
Many observational studies of rainfall identify both high intensity rainfall clustering in small areas and rainfall intensity decreasing with distance from the point of highest intensity. It is also found that as the rainfall intensity increases, the variation of intensity over distance also decreases.
This paper presents a simple technique using the velocity depth product (VxD) to classify floodways and floodplain development zones using 2D models, and how to easily evaluate the impacts of future works and land-use changes within the floodplain for strategic planning. Examples are discussed and illustrated.
Historically Hastings District Council held permits for discharging stormwater from their reticulated and open channel network to carry stormwater from the built environment into receiving waters.
This paper talks about an innovative underground water storage system installed on Waiheke Island, New Zealand and subsequent monitoring. The paper will look at the quality of the water, how it was re-used, demand analysis and discuss why designers of stormwater management systems in water plentiful New Zealand should be considering re-use more, and some of the barriers to uptake in New Zealand.
This paper presents a case study for a commercial development in the Hobsonville Peninsula, which faced the challenge of accommodating large volumes of runoff from the 20ha catchment with 9.4ha of roof area. A review of an innovative approach to addressing the catchment wide stormwater management objectives was undertaken, which included the assessment of re-use demands for not only the subject site but the wider community.
This paper presents the findings and recommendations from a review, commissioned by the Auckland Regional Council (now Auckland Council), into the design of stormwater management ponds within the Auckland region. It includes a literature review of current best practice and performance data, both internationally and within New Zealand.
Fraser Thomas were commissioned by GP Farms Ltd to prepare a Stormwater Management Plan for a new motorsport complex and associated Business Park covering some 90ha at Hampton Downs, North Waikato. This paper describes the stormwater management systems adopted for the complex and the issues experienced in implementing these systems in a unique and dynamic motorsport raceway environment.
NIWA is leading a collaborative FRST-funded programme to assist local government to assess risks associated with climate change in the urban environment and identify opportunities for reducing those risks. The aim is to create an Urban Impacts of Climate Change “tool-box” of methods and processes to assess the risk of climate change impacts and responses to them across different aspects of urban resource and hazard management.
The paper concludes the method provides a robust and simple method for determining Manning ‘n’ for designing high performance roadside vegetated swale drains and filter strips and recommends more physical modeling be undertaken to extend the information available.
This paper reviews the results of this study and those of others to consider the role that road surfaces play in influencing the generation, transport and removal of contaminants discharged in road runoff.
The NZ Transport Agency (NZTA) is developing an Erosion and Sediment Control Standard for State Highway Infrastructure. With careful planning and design, adverse effects of sediment discharges resulting from construction and maintenance activities can be avoided or minimised.
This paper details the flood hazard mapping study of the Wairoa River and Taitaia Stream that Tonkin & Taylor carried out for Manukau City Council. The purpose of the study was to provide flood extents that can be used in the Clevedon Village Sustainable Development Plan, and be incorporated into a plan change to the Manukau Operative District Plan for Clevedon Village. The plan provides for the expansion of the existing Clevedon settlement onto the rural land outside the existing village core and between the Wairoa River and Taitaia Stream.
This paper examines how a 1-D hydraulic model simulating the linkage and hydraulic behaviour between a low flow channel and floodplain was discretised (for a river corridor with a significant difference in flow length between channel and floodplain). It also describes how this setup enables the modeller to simulate mitigation options such as formalising a straight overland flow path and discusses the advantages, effects and constraints of mitigation options and the model setup.
The paper also summarises the initiatives and approaches, which have been taken or will be taken to overcome the above challenges in integrating stormw ater operations for the region. The Key performance Indicator (KPI) results in relation to customer services over the past four months indicate that these initiatives and approaches are successful as the new Auckland Council Stormwater Unit maintains its business as usual. The challenges for stormwater operations are now to improve on this delivery after the initial transition period.
This paper describes the operating options investigated. It outlines reasons why stakeholders favoured different options and the process the project partners went through to finally settle upon their proposed operating strategy. It details the impacts of the proposed operating strategy and the mitigation measures recommended offsetting adverse effects identified.
This paper describes the features of the area, the works completed to date and those remaining. The joint cooperative approach of Central Government, Regional Council, District Council, community and key infrastructure owners to produce a comprehensive solution is discussed.
This paper will outline how a paradigm shift (for both Council and community) represents a leading approach to flood and river management for a local authority. Solutions are being developed from the community up, rather than just presented as worked-up options from Council, as would normally be the case.
Kaeo River Catchment located in Northland covers 12,600 hectares of land with a total stream network of 90 kilometres. Flooding of the lower catchment including Kaeo Township has been identified as a significant hazard for many years. Several flood risk reduction mitigation options have been proposed in the past by stakeholders but without any sound technical basis.
In this paper, recorded rainfall data are used to quantify the relationship between infiltration basin volume and the performance of the infiltration basin in terms of, volume of runoff treated, time spent by stormwater in the infiltration basin and the statistical significance of overflow events.
The existence of TP 124 and TP10, the Auckland regional government guidelines for incorporating Low Impact Design (LID) techniques, indicate to me that this region is switched on to a forward thinking stormwater management philosophy.