Wednesday, August 03, 2011

Managing the flood risk

Localised flooding occurs frequently in the Horizons Region and with over half of the region's population living on floodplains, keeping people and their livelihoods safe is a big job for Horizons Regional Council.

Preparation is a key part of that and managing the rivers through engineering works allows Horizons to help prevent floods and provide adequate land drainage when necessary. Horizons manages 30 river and drainage schemes across the region, and maintains over 460 km of stopbanks, 700 km of drains, 20 pumping stations and 53 dams.

Their work doesn't stop there though, when the rain comes it's Horizons role to respond and reduce the risk to people and their property where ever possible.

"Streams and rivers stretch across our region like arteries throughout your body. They can rise and fall rapidly and we need to keep a constant eye out for any threat they may pose," says Horizons' emergency manager Shane Bayley.

To help them do this, Horizons collects flood warning data from a network of river and stream monitoring systems that provide up to the minute information about river heights and flows.

Mr Bayley says the importance of accurate data cannot be underestimated when it comes to making decisions in an emergency situation.

"The recording sites are equipped with one or more sensors, a data logger and communications equipment. The data is recorded every 5 to 15 minutes and transmitted back to a computer at our Palmerston North office in most cases every 30 minutes.

"With this data we can determine what action is required, anything from operating flood gates to evacuating people if necessary."

But it's not just staff that are able to access the information, Horizons shares the information publically within minutes of receiving it.

The data is sent to Horizons' website and distributed via an interactive voice response system (IVR). The IVR issues the flood warnings to subscribed users by phone when river levels rise to a level specified by the user depending on their circumstances. For example a farmer may wish to receive a notification if stock is grazing near a waterway in order to have sufficient time to move the animals to higher ground.

When the river rises to the designated level, Horizons' computer system identifies this and automatically calls those who have requested notification at that water level. The system will retry three times.

Horizons said most users of the IVR service are rural, however there are also some urban users in areas prone to river flooding.

The public can find out more about the IVR by calling Horizons on 0508 800 800.

ENDS

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