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One method of enhancing the health of receiving water ecosystems is to ensure that local plans and practices guiding urban development are underpinned by appropriate design principles. This paper reports on a policy and practices framework developed in New Zealand, and investigates the uptake and implementation of Low Impact Urban Design and Development (LIUDD). A hierarchy of LIUDD principles has been developed as a foundation for policy development in statutory and non-statutory plans and guidelines. Each principle is accompanied by practical implementation methods using sustainable technologies in a local context. Greenfield developments in urban growth areas in the Netherlands, Australia and New Zealand are assessed with respect to elements of the framework. The assessments show that the LIUDD principles are relevant internationally across greenfield developments of similar town and catchment scales. Application of the principles can inform decision makers so that they become more critically aware of aquatic sustainability imperatives in the urban design and redevelopment process.Keywords: Low Impact Urban Design and Development; water sensitive urban design; catchment management; urban water planning *

Strategic Environmental Assessment (SEA) and Cumulative Effects Assessment (CEA) are the focus of this research that investigated the evolving response in plans to the biologically undesirable accumulation of copper and zinc in a New Zealand estuary. Sources of metals are influenced by policies and plan provisions for land use, transport, stormwater management and boat moorings. During four decades of local government reform, plans responded to the scientific evidence of accumulation with increasingly sophisticated stormwater management. Despite the less explicit inclusion of SEA in New Zealand legislation, this research demonstrates for international audiences the concurrence of jurisdictional amalgamation; growing awareness and knowledge sharing across scientific, engineering and planning practitioners; and a steady improvement in plans to enable a marked slowing in cumulative effects (CEs) of urbanisation. A proposed Auckland Unitary Plan (PAUP) attempts to address some cumulative effects within watersheds now no longer divided by jurisdictional boundaries.

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This New Zealand research focuses on providing evidence that a specified residential land use layout plus "at source" stormwater management results in higher aquatic ecosystem health. The evidence provides justification for changes in statutory plans, policies and practice rules that direct urban development. The surveyed sites are within river basins clustered by similar residential land use density. Each cluster includes one river basin with conventional urban form and drainage. Other comparative basins in the cluster typify a "water sensitive" urban form and infrastructure. An index of biotic integrity (indicating river health) is determined for each waterway at annual intervals over years. Current plan requirements, policies and practice guidelines for urban development are critiqued in relation to survey results. The cumulative influence of defined residential river basin characteristics (drivers) are related to the holistic biotic indices. Combined drivers determine the cumulative aquatic health outcome. Research methods typically don"t target the effects of a single driver. Policy, plan and practice requirements need to guide urban design and construction to incorporate the elements of urban form that are together necessary for aquatic health. This will ensure an order of magnitude improvement in the functionality and recreational appeal of streams, wetlands, lakes and recipient harbours.