Improving stormwater management

The Project CARE Kokopu Connection, North Shore City Council's project to obtain resource consents for the ongoing operation of stormwater and wastewater networks, is now considering options to improve stormwater management across the city.

Works and environment committee chairperson, Joel Cayford, says that North Shore City is looking at ways to move from 'turtle city' to 'sponge city'.

"This means that property owners, as well as council, will need to take more responsibility for the stormwater that falls on their property and reduce runoff.

"As part of the city's major consultation planned for March next year, we will be asking property owners to consider options and priorities for stormwater management projects, and to consider how they can take responsibility for the stormwater that falls on their sites," Councillor Cayford says.

"In addition, our council will be assessing future investment in the existing piped stormwater network against the use of alternative technologies, which better soak up stormwater and reduce its effects on the environment.

"Our stormwater network is expensive, transfers the problem downstream, and results in an environmental headache, which is very expensive to cure. On-site alternatives will need to be considered.

"These are likely to include solutions such as reducing asphalt, concrete and other hard surfaces in new developments, appropriate planting, promoting rain tanks and using rainwater for non-drinking water uses around the home," he says.

North Shore City Council will decide on a number of potential stormwater projects that include:

* Reducing flooding to habitable floors;

* Improving water quality by creating wetlands, and installing litter booms, catch pit filters and other devices for reducing contamination of stream and beach water;

* Erosion control;

* Stream restoration and protection;

* Reducing overland flow; and

* Extending stormwater reticulation.

The council's water services general manager, Geoff Mason, says the decisions to be made next year could have a significant impact on the city's budget.

"It is essential that we achieve a sensible balance between new infrastructure to be provided by council and the kinds of solutions for which property owners can take responsibility.

"Currently the stormwater component in the annual rates is about $145 per household. At this current level of investment the improvements that we expect to be needed will take more than 50 years to complete," Mr Mason says.

"It is anticipated that per annum household costs could increase by $50 over 10 years, and as much as $90 -150 over 20 years, if the programme were to be accelerated.

"Our objective will be to reduce the impact of stormwater as our city grows, by reducing runoff.

"This change in approach is being driven by a need to protect our natural environment for the benefit of residents now and in the future.

"The Long Bay Structure Plan, supported by council this year, is an indication of some of the stormwater management methods now considered best practice, that we will be seeking to incorporate across the city, in the future.

"Our community's views will contribute to council's decision on the resource consents and long term plans to improve stormwater management. We're looking forward to hearing what the community considers to be the priority," Mr Mason says.

© Scoop Media