20 January 2011 Chapter 9 - Coastal Marine 9.18 Objectives and Policies Objective 1 To manage the Wairau River and Wairau Diversion mouth entries as hydraulically efficient openings to the sea for tidal flushing flows and river flows. Policy 1.1 To maintain direct openings of the mouths of the Wairau River and Wairau Diversion. 9.19 Methods of Implementation Council Activities To maintain existing river mouth rock level guide banks for the Wairau River and Diversion mouths, and extend them seawards as necessary. To excavate pilot cuts through the beach bar as and where necessary for a direct mouth of the Wairau River and/ or Diversion. Monitoring To maintain water level recorders which measure the tidal variation in the Lower Wairau River and Diversion and hence hydraulic efficiency of the mouths. To carry out surveys of salinity, tidal flushing flows, flow circulation, water quality and how these may be affected by the state of the Bar and to determine the effects on ecological values. Rules Rules will be used to specify the manner in which pilot cut opening of the bar is carried out and the manner in which the rock guide banks may be extended. A hydraulically efficient river mouth has environmental, drainage, navigation and flood control benefits. These combined tidal flushing flows and river flows can be concentrated by a guide bank to inhibit the development of the bar. At least 3 such guide banks or jetties of increasing effectiveness have been built by river or harbour authorities over the last 85 years. These guide banks have been very effective, and their presence controlling the bar is now generally considered the “status quo” situation. The manner in which the river mouth is kept open and timing of such works to achieve this needs consideration of a range of factors and their monitoring. 9.20 Issue Disturbance and alteration of the foreshore and seabed. Reclamations No reclamations other than a portion of the Wairau Bar have been undertaken along the East Marlborough Coast open coastline to date. 9 - 15