Volume Two 2. General Rules 2.9.1.4. No greater than 10% of the cross-sectional area of the lakebed or riverbed must be disturbed. 2.9.1.5. Any release of detritus from around a culvert, bridge pier or abutment must be carried out by mechanical or other physical means. 2.9.2. Protection works in, on or over the bed of a lake or river for existing structures. 2.9.2.1. The structure must have been lawfully established. 2.9.2.2. There must be no reduction in the capacity of the river at the structure. 2.9.2.3. Rock may be used for protecting existing structures. 2.9.2.4. Rock from damaged or redundant structures may be recovered from the lakebed or riverbed. 2.9.2.5. Continuous lengths exceeding 50m of vertical gabion bank walls must be avoided by interposing some gently sloping sections for bird access. 2.9.2.6. Motor vehicle bodies, old machinery and scrap iron must not be used for bank protection works. 2.9.2.7. Placement of rock rip-rap in estuarine areas must not take place between 1 August and 30 November in any year. 2.9.3. Suction hose intake placement over the bed of a lake or river. 2.9.3.1. The take and use of water must be authorised as a permitted activity or by a resource consent. 2.9.3.2. The intake must be screened to prevent fish from passing into the intake at all times. 2.9.3.3. A grid reference and details of the intake must be supplied to the Council within 10 working days of placement. 2.9.4. Construction of a dam on an ephemeral river. 2.9.4.1. The dam must not be within 8m of a perennially flowing or intermittently flowing river. 2.9.4.2. The dam must not intersect groundwater. 2.9.4.3. The dam must not be located in, or within 8m of, a Significant Wetland. 2.9.4.4. The dam must not be built within 500m upstream of a dwelling, formed public road or designated rail infrastructure. 2.9.4.5. The dam construction activity complies with all the permitted activity excavation, filling and vegetation clearance rules for the zone in which the activity is taking place. 2.9.5. Construction or placement of a new structure in, on, under, or over the bed of an ephemeral river. 2.9.5.1. The structure must not be within 8m of a perennially flowing or intermittently flowing river. 2.9.5.2. The structure must not intersect the groundwater. 2.9.5.3. The structure must not be located in, or within 8m of, a Significant Wetland. 2.9.5.4. The construction or placement must comply with all the permitted activity land disturbance rules for the Zone in which the activity is taking place. 2 – 13