Farmers near the peat dome expect winter flooding, but the March and April floods caused by cyclones Debbie and Cook were more extreme than normal, and many are questioning if changes to water management within the dome exacerbated the flooding.

Andrew McGiven, president of Waikato Federated Farmers, says not only was the flooding extensive, but pastures also remained under water for long periods of time.

“Federated Farmers is trying to work with the Waikato Regional Council to establish the issues which could have affected the flooding and whether weirs in the peat dome made it worse.

“Farmers in that area pay between $15-20,000 in rates for the flood protection scheme and they are entitled to expect a certain level of service.”

Andrew says it appears at least one weir within the peat dome is unconsented and if it had helped reduce the speed at which flood waters drained, then action needs to be taken. “If it was a dairy farmer who had done something similar, then council would be quick to take them to the Environment Court. We expect some consistency from council on this issue.”

Number of questions

Karen Botting, Waikato Regional Council Hauraki zone manager, says the flood events have raised a number of questions and enquiries, including about weirs in the Kopuatai Peat Dome.

“We’re working with the Department of Conservation and others as we make inquiries into the dome issues.

“We are unaware of any weirs in the Kopuatai Peat Dome on the eastern side being installed recently. There is a weir on the eastern side of the ABCD Flax block which has been managed previously by DoC and WRC. The future management of this structure is under review.”

Regarding other weirs, Karen says council’s assessments to date have identified six consented DoC weirs and one non-consented weir with unidentified ownership.

“All the consented weirs were operating as per consent conditions. The non-consented weir is being checked out. The impact of all weir water levels is being incorporated into the Piako Scheme review to enable specific analysis of their impact on the flood events.”

Water level assessments

The regional council also manages three weirs which were installed prior to the Resource Management Act for flood protection purposes.

“As part of the technical reports on the flood events, an assessment of the management of water levels within the ABCD Flax block is being undertaken with DoC. 

“Meanwhile, we are preparing technical reports (one each for March and April) providing detailed factual information on the weather systems that impacted the region, including rainfall, flow amounts and frequencies, as well as an assessment of how ‘big’ the events were.

“These reports will provide the basis for more detailed assessments into how the Waihou, Piako and lower Waikato flood schemes performed during the March and April events. These assessments will aim to address many of the questions that are currently being asked by the community.

“However, it’s important to understand that given the complexity of this series of events, as well as how the schemes were impacted, it is not expected that all additional information will be available until late 2017,” says Karen.