SECTION 3 Site Investigations & Results C:\D Data\GWS C Drive\GWS\Client Files\1344 OGL - WKP\4 Deliverables\WKP Final Draft Report\June Report\WAI-985-000-REP-LC-0030. Final_Rev_0.docx 28 drainage pattern the T-Stream vein is near perpendicular to the groundwater through flow direction, whereas the EG vein is near parallel to the groundwater through-flow direction (refer Figure 26). This observation indicates driving heads through the T-Stream vein system are likely to be greater than in the EG vein. Deep groundwater discharge occurs at an elevation of approximately 300 mRL at the headwaters springs near the contact of the post mineralisation Andesite and underlying rhyolitic rocks (refer Figure 19). These springs are created by groundwater discharge through localised hard Rhyolite flow outcrops that have formed an inflection in topography, allowing discharge at the surface and surface waters. This groundwater discharge provides some baseflow to the streams under low flow conditions. Figure 26 Catchment Scale Groundwater Flow Shallow, perched groundwater is present in the soil Regolith and this is recharged from rainfall. The Regolith water drains laterally down slope as interflow and discharges into the stream. Interflow is the dominant source of water supporting the streams and is a high input during and following rainfall. These soils have a high capacity to store water which recedes over time providing stream flow. In summary, groundwater recharge is via direct rainfall or through flow. Groundwater discharge to the Streams is via deep groundwater at contact springs high in the catchment or from interflow drainage. The stream section below around 250 mRL is neutral under low flow conditions, there is no deep groundwater discharge from the rockmass. This section of the stream is formed in the rhyolitic host rock that will be partially dewatered during mining but, given it does not create baseflow, no loss to the stream is expected to occur. Below the Thompson Stream tributary, the Wharekirauponga Stream flows over post mineralisation
RkJQdWJsaXNoZXIy MjE2NDg3