The Taylor River Flood Detention Dam, built in 1965, is the largest of its kind in New Zealand. It is 20m high and involved 400,000m³ of earthworks. The dam operates by detaining a one-day flood in the dam to release its flow over two days, thereby reducing a 300 m³/sec flood peak to a 108 m³/sec peak.
The Wairau Diversion is also the largest of its kind in New Zealand. It is capable of carrying 3,000m³/sec - 55 percent of the Wairau River's flow - on a direct, shorter path to the sea. Some 2,000,000m³ of material has been removed from the diversion channel.
The Conders stopbank/groyne at Conders Bend near the Wairau (Renwick) bridge on State Highway 6 is vital in keeping the Wairau River out of the old Upper Opawa River channel that leads to Blenheim.
Other river works data is:
|
Works |
|
Stopbank
Length |
|
Rock in
Banks |
|
Wairau Floodway |
|
98km |
|
850,000 tonnes |
|
Upper Opawa/Roses Floodway |
|
45km |
|
70,000 tonnes |
|
Lower Opawa/Taylor Floodway |
|
44km |
|
50,000 tonnes |
|
|
|
|
|
|
|
Drainage Channels
Length |
|
Drainage
Flood Pumps |
|
Lower Wairau Drainage Area |
|
160km |
|
47 |
