Water flow data were collected from various river monitoring sites along the catchment water path feeding the Waipori Power Station. Data are presented as daily mean flow (l/s) and flow (m3/s). Three flow recorders are situated at the intake weir in the upper Deep Stream catchment(measuring Deep Stream flow above the weir (site 7444), inflow into the intake flume (site 7443) and flow returned to Deep Stream below the weir (site 7442). A further recorder (site 7445) measures the flow discharged into Lammerlaw Stream at the end of the diversion tunnel and pipeline. This Lammerlaw Stream water flows into Lake Mahinerangi providing additional water for the Waipori generation scheme. During 2008 the Deep Stream diversion was modified to allow water to be diverted to another storage reservoir via a gate structure in the pipeline 2 km before the Lammerlaw Stream Discharge flow recorder (site 7445). A new site (Deep Stream at Downstream Rollergate, site 7446) was installed in this new diversion in November 2008 to measure the flow to the new reservoir and 2 new hydro generation stations. Minimum flow requirements in the lower catchment are monitored at the site Deep Stream at 60 Foot Weir (site 74350). This site is 6 kilometres downstream of the Dunedin City Council Water Department intake on Deep Stream.

The Waipori Power Scheme uses the outflow from Lake Mahinerangi, passing this flow through four dams and power stations in the upper Waipori gorge. The data and associated report provide flow information in the lower Waipori Gorge below the last (No. 4) Power Station, and below the last Weir (No. 4). The flow recording site (74395) was located three kilometres below the No. 4 Power Station at grid reference H44:802714. The site was shifted upstream on 15 August 2003 to a location 200m downstream of the power station (H44:789715) to enable TrustPower to monitor the flow information by linking the station Program Logic Controller to the site. The flow recording station at H44:777721, site (74398) below the No. 4 Weir was installed on 19 November 2003 for monitoring of minimum flows and ramping rates downstream of the Weir. The following outputs are available from the quarterly data Oct to Dec 2014. Tabulation of daily mean flows at site 74395 for the Waipori at Below No. 4 Power Station from 1 January to 31 December 2014. Full range plot of flows at site 74395 for the Waipori at Below No. 4 Power Station for the reporting period from 1 October to 31 December 2014. A partial range plot (<1000 l/s) to better show the detail of the low flows at site 74395 for the Waipori at Below No. 4 Power Station from 1 October to 31 December 2014. A tabulation of daily mean flows at site 74398 for the Waipori at Downstream No. 4 Weir from 1 January to 31 December 2014. A full range plot of flows at site 74398 for the Waipori at Downstream No. 4 Weir from 1 October to 31 December 2014. A partial range plot (<500 l/s) to better show the detail of the low flows at site 74398, for the Waipori at Downstream No.4 Weir from 1 October to 31 December 2014.

Monowai Power Station utilises the outflow from Lake Monowai. This flow is controlled by gates at the lake outlet, and travels several kilometres down the Monowai River before being diverted by a weir into a canal leading to the Power Station and released into the Waiau River. At the diversion weir, a flow is released through the fish-pass and down the Monowai River to maintain a minimum flow. The lake outflow is monitored at site no. 79712 (Monowai at Below Gates). Lake level is recorded at site no. 79713 (Lake Monowai at Hinchey’s Outlet). Flow down the lower Monowai River below the diversion weir is monitored at site no. 79715 (Lower Monowai at Below Weir); this station was installed on 10 April 2003 for resource consent monitoring. The report summarises the data from these sites for the quarterly period – 1 October to 31 December 2014, and in the context of the full record since 1977. Data and outputs cover: Daily Mean levels at Site 79713 Lake Monowai at Hinchey’s Outlet from 1 January to 31 December 2014. Daily mean outflows (m3/s) at Site 79712 Monowai River at Below Gates from 1 January to 31 December 2014. Daily mean inflows (m3/s) at Site 9540, Lake Monowai at Inflow from 1 January to 31 December 2014. Daily mean flows (l/s) at Site 79715, Lower Monowai River at Below Weir, from 1 January to 31 December 2014. Monthly mean levels (lake level in metres, in terms of Monowai datum) at Site 79713 Lake Monowai at Hinchey's Outlet from June 1977 to 31 December 2014. Monthly mean outflows (m3/s) at Site 79712 Monowai River at Below Gates from 1 October 1976 to 31 December 2014. Lake levels at Site 79713, Lake Monowai at Hinchey's Outlet from 1 October to 31 December 2014. Outflows for Site 79712 Monowai River at Below Gates (blue), and Inflows (partial range, green) for Site 9540 Lake Monowai from 1 October to 31 December 2014. Full range inflows for Site 9540, Lake Monowai from 1 October to 31 December 2014. Flow at Site 79715, Lower Monowai River at Below Weir, from 1 October to 31 December 2014. Lake Monowai at Hinchey's Outlet, lake level Lake Monowai at Hinchey's Outlet, water-level distribution from 13 May 1977 to 31 December 2014. Monowai River at Below Gates, outflow from 2 September 1976 to 31 December 2014. Lake Monowai - outflow distribution over the full period of record from 2 September 1976 to 31 December 2014.

Understanding and identifying pathways and processes affecting sediment, nutrient and faecal contaminant inputs from agricultural catchments to streams can improve environmental management strategies and provide a base for estimating the performance of various edge-of-field mitigations, such as riparian buffers and constructed wetlands. It can also provide estimates of the time lag between when changes in land use practices occur are implemented and when water quality effects that result from these changes are likely to be observed. The Hydrological flow Path Explorer is web based tool to characterise watersheds according to the major flow pathways: overland flow, shallow sub-surface flow, a mix of overland and shallow subsurface flows, or deep ground water flow. This tool was developed using publicly available spatial and temporal data for New Zealand, such as digital elevation maps, fundamental soil layers, rainfall maps, stream flow records and other physical characteristics of catchments. Hydrological Flow path Explorer help to visualize different flow pathways for all streams with Strahler 1st order and higher for New Zealand rivers. The flow pathway analysis results can support the development of recommendations for riparian buffer design. In this study, dominant flow pathways were defined by firstly applying flow separation based on observed flow at the outlet of the catchment using the methodology given in Singh et al. (2019) and secondly based on the HYPE hydrological modelling framework given in Srinivasan et al. (2020) and Singh et al. (2021). The Hydrological Flow path Explorer gives the contribution in % of total simulated at subcatchment outlet as SF is surface runoff; IF is interflow; Tile is tile drainge; SGF is shallow groundwater flow; DGF is deep groundwater flow for the River Environment Classification system (Snelder and Biggs, 2002) Strahler 1st order subcatchment boundaries. It also shows Base flow index (BFI) for the River Environment Classification system (Snelder and Biggs, 2002) Strahler 1st order subcatchment boundaries. Singh, S.K., Pahlow, M., Booker, D.J., Shankar, U., Chamorro, A., 2019. Towards baseflow index characterisation at national scale in New Zealand. Journal of hydrology, 568: 646-657. DOI:https://doi.org/10.1016/j.jhydrol.2018.11.025 Singh, S. K., Pahlow, M., Goeller, B., Matheson, F., 2021. Data- and model-driven determination of flow pathways in the Piako catchment, New Zealand, Journal of Hydro-environment Research, Volume 37, 2021, Pages 82-94, https://doi.org/10.1016/j.jher.2021.06.004. Snelder, T.H., Biggs, B.J.F., 2002. Multiscale River Environment Classification for water resources Managements. JAWRA Journal of the American Water Resources Association, 38(5): 1225-1239. Srinivasan, M.S., Muirhead, R.W., Singh, S.K., Monaghan, R.M., Stenger, R., Close, M.E., Manderson, A., Drewry, J.J., Smith, L.C., Selbie, D., Hodson, R., 2020. Development of a national-scale framework to characterise transfers of N, P and Escherichia coli from land to water. New Zealand Journal of Agricultural Research: 1-28. DOI:10.1080/00288233.2020.1713822 For any query, please contact Dr. Shailesh Singh [email protected] 03 343 8053_ ______________________________________ Item Page Created: 2021-02-18 03:49 Item Page Last Modified: 2022-09-27 15:38 Owner: [email protected]