|Title||Project Twin Streams Case Study|
|Publication Type||Case Study|
|Year of Publication||2014|
|Authors||Smith T.F, Thomsen D.C|
|Keywords||Auckland, property acquisition|
Waitakere City (population approximately 204,000) is located within the Auckland Regional Council area of New Zealand. The Project Twin Streams area focused on in this case study covers 10,000 hectares of mostly urban residential development intersected by streams draining from the Waitakere Ranges to the west of Auckland and flowing into a number of other streams and the Waitemata Harbour.
Development within the catchment has enlarged the extent of impermeable surfaces leading to increased storm water runoff, erosion and sedimentation of streams and flooding of houses. Storm water studies and flood modelling carried out in the late 1990s resulted in the development of Project Twin Streams in 2002. Recognition of the likelihood of more frequent and severe storms projected from climate change have also focussed attention on addressing problems related to flooding (Atlas Communications & Media Ltd 2010).
The objectives for the Project are consistent with sustainability principles for long-term social and environmental well-being. After consideration of storm water studies, flood plain modelling and engineering options, the Council decided that acquiring the private properties lying within the 100-year flood plain level to allow natural flow paths and flood reserves would best meet these objectives.