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Hydrology

The Parapara River catchment comprises 37 square kilometers of largely bush-covered steep gully and narrow ridge topography. There is no rainfall gauging within the catchment however the TDC operate automatic stations at Bainham, in the Aorere River catchment and in the Anatoki on the eastern side of the Parapara Ridge. Both provide reasonable data, albeit from a lower altitude.

Envirolink Ltd is retained to provide ongoing hydrological data. Flow measurements have been recorded at Richmond Flat since 16.05.03. At this time the extended summer drought of the 2003 summer had not yet broken and a flow of 39 l/second was obtained from 150 metres above the dam. Data logging at the dam has recorded a rise in water levels of 2.4 metres and an average flow for the day of 4 June 2003 of 13000 l/sec.

The catchment above Richmond Flat is 31.2 km2 in area. Part of this catchment is in Mt Arthur Marble and the possibility exists of some flow being captured by an associated cave system to discharge elsewhere. On 14.05.03 the catchment was producing a flow of 12.1 l/s/km2 above the dam and flow measurements on the same day at Bassets, below the gorge with a catchment area of 35.8 km2 at 492 l/s equated to a catchment flow of 13.7 l/s/km2. This data suggests that flow capture into the marble is not of great significance.

300 metres below Richmond Flat the first of 3 tributaries, Dam Creek, enters the Parapara Gorge adding significant additional water to the residual flow over the Dam.

Appendix #1 provides a preliminary estimate of the likely long term median flows.

Botany

Uruwhenua Botanicals, represented by Dr Philip Simpson has been retained to provide expert advice on the botany. He notes a diverse range of habitats and species in the original and regenerating forests and concludes in his view that vegetation clearance associated with this project would not impact to an unacceptable degree with attention to avoiding significant specimens and swamp coprosma shrubland.

Dr Simpson's report on the vegetation of the area is attached as Appendix #2

Archaeology

This section of the Parapara River has some record of Maori occupation and use. Later occupation may have been by those taking refuge from the deprivations of the conquest of the area by forces loyal to Te Rauparaha around 1828. This proposal is not expected to disrupt any noted sites of significance to Iwi.

Significant European occupation began after the discovery of gold in 1857 and activities by individuals and then companies continued until the 1930's. Some of this mining activity was carried out by Maori.

More recently small scale suction-dredging for gold and in the early 1970's a reinvestigation of the mineralisation at Red Hill resulted in the formation of the access road to Richmond Flat.

A report on the archaeology by Katharine Watson is attached as Appendix #3.

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