Volume Two 3. Rural Environment Zone (c) 8m of the landward toe of a stopbank and the depth of any excavation beyond that must not exceed 15% of the distance between the landward toe of the stopbank and the excavation. 3.3.14.4. The excavation must not occur on a slope greater than 7.5° if the activity is within a Soil Sensitive Area identified as loess soils. 3.3.14.5. There must be no excavation in excess of 10m within a Groundwater 3 Protection Area. 3.3.14.6. Excavation must not be within such proximity to any abstraction point for a drinking water supply registered under section 69J of the Health Act 1956 as to cause contamination of that water supply. 3.3.14.7. Excavation must not be within a Level 2 or 3 Flood Hazard Area, or in the Level 4 Flood Hazard Area in the vicinity of Conders Overflow. 3.3.14.8. There must be no excavation in excess of 500m per Computer Register 3 Computer Register located within the following Outstanding Natural Features and Landscapes within any 12 month period: (a) Chalk Range; (b) Inland Kaikoura Range; (c) Molesworth Station and Upper Clarence; (d) Limestone Coastline. 3.3.14.9. Wheeled or tracked machinery must not be operated in, or within 8m of, a river (except an ephemeral river or intermittently flowing river, when not flowing), lake, Significant Wetland or the coastal marine area. 3.3.14.10. Batters must be designed and constructed to ensure they are stable and remain effective after completion of the excavation. 3.3.14.11. Water control measures and sediment control measures must be designed, constructed and maintained in an area disturbed by excavation, such that the area is stable and the measures remain effective after completion of the excavation. The diameter of any culvert used to drain excavation must not be less than 300mm. 3.3.14.12. Excavation must not cause any conspicuous change in the colour or visual clarity of a flowing river after reasonable mixing, or the water in any Significant Wetland, lake or the coastal marine area, measured as follows: (a) hue must not be changed by more than 10 points on the Munsell scale; (b) the natural clarity must not be conspicuously changed due to sediment or sediment laden discharge originating from the excavation site; (c) the change in reflectance must be <50%. 3.3.15. Excavation or filling within the National Grid Yard. 3.3.15.1. Excavation within the National Grid Yard in the following circumstances is exempt from the remaining standards under this rule: (a) Excavation that is undertaken as part of agricultural or domestic cultivation, or repair, sealing or resealing of a road, footpath, driveway or farm track; (b) Excavation of a vertical hole, not exceeding 500mm in diameter, that is more than 1.5m from the outer edge of a pole support structure or stay wire; 3 – 18