Author:Thomas Civil and Environmental Consultants, Brett Stansfield
Source:Thomas Civil and Environmental Consultants | Auckland Council | Waitākere Ranges Local Board
Local boards:Waitākere Ranges
Project Twin Streams was initiated as a partnership between Waitakere City Council and the community aimed at improving the flood management, water quality and ecological health of waterways in and around Waitakere City. Since the amalgamation of city and district councils in Auckland in 2010, this partnership now exists between Auckland Council and the community.
The project includes planning and controlling urban development to reduce floods and control pollution, improving the treatment of stormwater, restoring native plantings along stream banks, clearing stream channels and developing wetlands to reduce pressures and enhance environmental values. Note all of this work has focused largely on the mid to lower reaches of the stream catchments as this is where community buy-in, education and amenity values have the greatest return on investment. Project Twin Streams covers the stream catchments draining to Henderson Creek and Huruhuru Creek. This includes the lower Oratia, lower Opanuku, Waikumete, and lower Swanson streams (Figure 1). These streams run through a mixture of native bush, rural and urban areas.
Thomas Civil and Environmental Consultants Limited (TCEC) has been requested to repeat the Pressure-State-Response investigative reporting previously carried out by other consultancies (Eco Water Solutions 2004, Kingett & Mitchell 2006, Golders 2010). This report has enhanced knowledge of the water quality, in-stream ecological effects and biodiversity outcomes of the PTS interventions undertaken to date, as well as updating the current state of pressures impacting on these streams.
The monitoring programme for PTS comprises:
- Pressure monitoring using urban infrastructural indicators, including percent land use, and community response measures such as riparian planting;
- Aquatic ecology and habitat quality assessments – current state
- Stream water quality and flow monitoring – current state
- Stream sediment quality monitoring – current state
This report documents water quality data collated during April and May 2016 and provides a summary of compliance of this data with environmental guidelines for aquatic ecosystem health and contact recreation. The reporting has been framed according to stream type using the river environment classification (REC) and land cover database version 4 to ensure that non-human induced effects of water quality (e.g. climate, source of flow, geology etc.) are factored out, thereby comparing like stream types.
Prepared by Thomas Civil and Environmental Consultants for Auckland Council