GHD | Oceana Gold New Zealand Ltd. | 12552081 | Waihi North Project E-3 Figure 1 Waihi WBM Outline E-3-2 Sources Rainfall Measured rainfall data is used to calculate runoff for each catchment area included in the Waihi North Project. Daily rainfall data was sourced from local rain gauges for the 100 simulation years between 1917 and 2016. Measurements are taken from; Cliflow agent 1550 (station B75381) for the period of 1/1/1917 to 1/1/1990, Newmont data for 1990 to 2010 infilled with Cliflow VCS (station P198205) data, and the Waihi met station for 2011 to 2016 in-filled with B75495 and Mill gauge data. These data have been utilised as representative of the operations at Waihi. In addition rainfall data from the Golden Cross rainfall gauge (NZTM 1846987, 5865767) has been utilised to calculate runoff for the catchments associated with the Wharekirauponga component of the project (Ohinemuri and Wharekirauponga catchments). This rainfall gauge includes records from 1991 to present and the record has been extended by extrapolation from the overlapping period with the extended Waihi data set. Runoff Areas Daily rainfall on each catchment area determines the flow into associated ponds. All collection ponds identified in the model are pumped to the WTP as Priority One (inclusive of process area runoff, seepage, collection ponds and WUG groundwater) and the aim is to keep the level of these ponds low to maintain capacity for high rainfall events. Table1 provides a summary of the maximum catchment areas considered in the WBM for each area and the corresponding runoff coefficients. Each
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