54 Stream channel has excessive sediment loads and banks are collapsing. No riparian vegetation Stream channel reasonably unmodified, some bank erosion No riparian vegetation Stream channel natural Native riparian vegetation with closed canopy Stream channel has excessive sediment loads and banks are collapsing. Riparian exotics, no canopy closure Stream channel has excessive sediment loading and banks are collapsing Riparian restoration on TRB 11.0 Surplus Rock Management (Northern Rock Stack) 11.1 Introduction The Northern Rock Stack is planned to contain up to 7 million cubic metres of material and is constructed to a nominal height of RL 173 m. Also proposed are topsoil stockpiles, two of which are constructed at the northern extent of the Company owned land and adjacent to Golden Valley Road. 11.2 Ecological Values 11.2.1 Background The proposed footprint of the NRS encompasses a significant portion of the stream ‘TB1’, its tributaries and associated features (Figure 13). To better understand the freshwater environment within the NRS footprint, two SEV surveys were undertaken within the two dominant stream habitat types within the footprint. Site TB1_lower was located on the main TB1 Stream some 200 m upstream of the confluence with the Ohinemuri River and was chosen for its representativeness of the TB1 Stream. Site TB1_upper was located upstream on a tributary to the TB1 stream and was selected for its representativeness of the stream habitats within the eastern extent of the NRS footprint. Habitat characteristics of the TB1 stream are provided in Appendix 4. In addition, a former constructed silt pond that has since been rehabilitated and naturally recolonised occurs in the mid-reaches of TB1. The characteristics and historic photographs of this former silt pond feature are provided in Appendix 2. 11.2.2 Habitat Site TB1_lower had a reasonably wide (1.7 – 3.4 m) channel with a predominantly silt/sand substrate with the occasional small gravel present. Water flow was slow, with large and deep pools (up to 1.26 m deep) present along the reach and some areas of anoxic sediment. Riparian vegetation had been planted to approximately 10 m either side and fenced off from the surrounding grazed pasture. Native species such as flax, lemonwood, cabbage tree and mapou
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