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It may sound like a new style of music, but "rock rip rap" has a far more productive meaning for the protection of a state highway bridge and South Island community.
Recent completion of the work by New Zealand Transport Agency (NZTA) at Omarama Stream Bridge on State Highway 8, just outside the town of Omarama in the Mackenzie Basin, has resulted in the bridge being strengthened and made more resilient and the flooding risk at the site reduced.
Significant flooding events at Omarama in 2009 and 2022 raised concerns about further events in the future, and NZTA acted by putting in place a plan involving what is known as the "rock rip rap" method.
In a statement, NZTA lower South Island maintenance and operations area manager Chris Harris said it was always satisfying to complete projects that had a clear benefit for both the highway network and local community.
"Contractors for NZTA removed built-up sediment [and] overgrown vegetation and opened up the waterway at the Lindis Pass end of the bridge, increasing the water carrying capacity under the bridge.
"Stop bank construction work has provided protection against flood waters, while use of rock that we call rip rap has been installed in the stream bed to strengthen the piers that hold up the bridge and prevent erosion and scouring."
He said after planning the project and obtaining the necessary consents, the physical work at the bridge took about three weeks to complete.
"We expect the final cost to be around $170,000, which provides good value for money.
"It also provides peace of mind for those living and working in the Omarama area as we see more frequent flooding events in New Zealand." — Allied Media