Chapter 17 - Natural Hazards 17.3.2 Objectives and Policies Objective 1 To minimise potential for loss of life and damage to property in the main Wairau floodplain (Rural 3 Zone) downstream of the Waihopai confluence. Policy 1.1 To maintain and upgrade to a uniform high standard the existing highly modified floodway systems as the primary mechanism of mitigating against the flood hazard. Policy 1.2 To attain a floodway capacity and standard of protection for flood sizes up to a 1 in 100 year return period for the major rivers on the floodplain. Policy 1.3 To provide and maintain a network of constructed channels and structures to remove local stormwater (and drainage water) and dispose of it into the major river floodways. Policy 1.4 Not locate houses and structures where damage could occur because of the effects of flooding where the flood standard in Policy 1.2 cannot practically be achieved. Policy 1.5 Define areas on suitable maps where a significant flood hazard exists and flood paths of extraordinary floods. Policy 1.6 Avoid locating urban or industrial development on flood path areas of extraordinary floods. Policy 1.7 Provide heavy rainfall and flood warnings and emergency flood response procedures. Objective 2 Management of areas outside the main Wairau floodplain that are susceptible to flood hazards so as to mitigate damage to property and infrastructures and to avoid loss of life. Policy 2.1 Locate houses and structures to avoid damage from the effect of the flood hazard. Policy 2.2 Maintain river channel efficiency and protection works where the benefits outweigh the costs. Policy 2.3 Define areas at risk from significant flood hazard as information becomes available. Policy 2.4 Provide heavy rainfall and flood warnings and emergency flood response procedures. Policy 2.5 To minimise bedloads of floodways by encouraging retirement of badly eroding areas of the mountain lands. The river works and floodways that have been imposed in the past on the Wairau floodplain rivers have completely altered them from their ‘natural’ state. The rivers are impossible to return to their former state. The Council, as river authority, now has the responsibility of at least maintaining the current river pattern to enable them to pass 17 - 5