Waitārere Beach during the annual Levin and Districts Brass Band Big Dig.
Concern over the behaviour of stormwater and unpredictable groundwater flow has been enough for Horowhenua District Council to park plans for the development of a large area of land east of Waitarere Beach.
Increased incidents of flooding on private property and reserves in the past two years have stymied efforts to rezone a 100ha block east of Waitārere Beach that potentially would have opened the way for 700 new homes.
The area was initially tagged for development in 2021 to help address rapid population growth forecasts in Horowhenua, a region predicted to grow from 37,000 to 62,000 by 2041.
But things have quickly changed. Since then, record high groundwater levels due to significant rainfall events had resulted in some properties flooding, while also stretching the town’s wastewater network to capacity.
The district council has moved quickly on the issue, the concern being enough to have those development plans officially withdrawn at a council meeting last week.
There were several key reasons the proposed plan change to accommodate the development won’t progress to a hearing stage, group manager community vision and delivery David McCorkindale said.
The most significant factor was a lack of understanding of the impact of groundwater changes that were observed last year and the management of the resulting overland stormwater flows across the Waitārere Beach settlement.
“At the time of notification, a report suggested sufficient capacity at the Wastewater Treatment Plant (WWTP) to accommodate growth. Heavy and long-duration rainfall events, especially in 2021 and 2022, resulted in record-high groundwater levels, resulting in ponding and flooding on private property and road reserve,” he said.
The council had met to consider three options: withdrawing the plan change, continuing to delay the plan change while exploring and resolving the issue, or proceeding to a hearing without a full resolution.
McCorkindale said groundwater infiltration and stormwater entering the wastewater network at the time resulted in the wastewater plant operating at full capacity and unable to handle more demand without upgrades to the plant and improved stormwater management.
“Addressing this issue may require upgrades to the sewage treatment plant, additional stormwater management techniques, or both. However, investigating and deciding on these measures will take time and require careful consideration of their priority against other council priorities and initiatives,” he said.
“Moreover, the Resource Management Act 1991 (RMA) mandates councils to proceed to hearings and decide on proposed plan changes within two years of notification,” he said.
“Unfortunately, the council is currently in breach of this timeframe. While the RMA allows for an extension, the timeframe for resolving the issues remains uncertain. This means seeking an extension is impractical, and fairness to submitters becomes a concern with prolonged delays.”
As a result, the council has adopted the recommendation to withdraw the plan changes until the impact of groundwater level variations was better understood.
Meanwhile, Mayor Bernie Wanden said it was important to note the withdrawal of this particular development plan did not signal the end of development plans for Waitārere Beach.
“A large number of new developments are already consented or planning is under way. Once the wastewater treatment plant issues are resolved and the impact fluctuating groundwater levels have on the stormwater overland flows are well understood, then council can revisit the development plan and initiate another plan change process,” he said.
“This means the Operative District Plan provisions, including the existing zoning, will remain in place and the work done ... can potentially inform future plan change processes.”
– Public Interest Journalism funded through NZ on Air.