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Stormwater flowing into our streams and onto our beaches can harm the environment and cause damage to private property. Major stormwater issues facing North Shore city include:
Flooding occurs in North Shore City because there are not enough stormwater pipes for the large volumes of stormwater. Intensive urban development increases hard surfaces such as roofs, driveways and courtyards and results in increased stormwater run-off. This contributes greatly to flooding. Erosion is caused when stormwater flows downhill. Increased overland flows resulting from intensive urban development and loss of vegetation increases erosion significantly. Water qualityWater quality is important to many people living in North Shore City.
Stormwater quality and the environmental effect Stormwater causes widespread and ongoing degradation of
the marine and freshwater environment. Our investigations as part of
Project CARE, our 20-year programme of works to improve
beach water quality, has shown that stormwater contributes
greatly to the deterioration of beach water quality along the
eastern coast of North Shore City.
The following table summarises the main contaminants
found in Auckland stormwater (Source: ARC TP 53). |
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Of the contaminants listed above, vehicle pollution and our roading system are the major contributors. The following table lists the proportion of contaminants sourced from the roads and vehicle use (Source: NIWA, October, 1995).
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North Shore City's stormwater assets had a total replacement value
of $228 million as of June 30, 1999. These assets must be managed efficiently to ensure they
continue to serve the city well. 
Water
introduction