Appendix 3: Methods for Assessment of Stream Freshwater Ecology Boffa Miskell Ltd | Waihi North Project: Freshwater Ecological Assessment | Additional fieldwork was conducted at the second impact site on 21st of January 2021. Weather conditions during the site visit were overcast with minimal wind. There was approximately almost 9mm of rainfall over the previous seven days. As part of the wider assessment of stream values, riparian values were assessed by walking over the sites and recording the native and exotic flora and their evident functional services. No quantitative methods were considered necessary to describe the riparian habitats present as they were small and non-complex habitats. Aquatic ecological values were assessed over representative reaches of the waterways. Habitat values were assessed following the rapid habitat quality assessment described in Clapcott (2015) and Harding et al. (2009). Spot water quality measurements (dissolved oxygen, temperature, pH, conductivity) were taken using a calibrated YSI ProPlus multiparameter meter within the unnamed tributary (impact site) and main stem of Mataura Stream. Composite sediment samples were also collected at the same spot water quality sites. The sediment quality samples were chilled before being sent to Hill Laboratories for analysis of nutrient and heavy metal concentrations. Sediment cover and grain size were measured at one location within the Mataura Stream using methods based on Clapcott et al. (2011). In particular, sediment assessment method 2 (in-stream visual estimate of percentage sediment cover) and method 3 (Wolman pebble count). A macroinvertebrate sample was collected within all assessed waterways. Samples were collected using a 500-micron kick net following Protocol C1, preserved in ethanol and analysed according to Protocol P1: coded abundance (Stark et al., 2001). Hard-bottom macroinvertebrate indices (MCI-hb and QMCI-hb) were calculated for all samples (Stark & Maxted, 2007) as well as species richness and number of EPT37 taxa. The fish surveys within the unnamed tributary 2 of Mataura Stream, involved electric fishing using a Kainga EFM300 backpack model. For the tributary 2, electric fishing was carried out at two locations along the tributary reach (two 75 m reaches downstream and upstream of a perched culvert near the access track). Any fish species observed during the site walk over were also recorded. Approximately 150 m of habitat was surveyed using the electric fishing machine. All native fish caught at each location were identified, measured, and released. The fishing survey was based on modified methods outlined in Joy et al. (2013), and considered to be adequate to provide an overview of the fish species present within the waterways. For all other Willos Farm sites fish data was taken from the NZFFD. Stream ecological valuation (SEV) data was collected for the two unnamed tributary of Mataura Stream (two impact sites) following methods outlined in AC (2011). The data was entered into the SEV spreadsheet designed for use in the Auckland region. Where watercourses were identified as intermittent we applied the SEV methodology for intermittent streams (AC 2016). Waihi (Northern Rock Stack, Gladstone, TSF3) A desktop assessment of relevant information from the proposed work areas was undertaken. Most of the information was drawn from the monitoring reports generated by OGNZL for the site, those reports being required under existing conditions of consent. Additional information has been derived from searches of the NZ Freshwater Fish Database and available records held by the Waikato Regional Council. 37 EPT: Ephemeroptera (mayflies), Plecoptera (stoneflies) and Trichoptera (caddisflies), the most sensitive aquatic macroinvertebrate species indicative of good water quality and habitat.
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