Description of the power scheme & assessment of effects: Parapara catchment
Description of the scheme
This proposal is for the re-establishment of the historic tunnel, water race and pipeline system
by the former Parapara Hydraulic Sluicing Company (PHSC) in hte Parapara River catchement for the purpose of
generating hydrelectric energy.
Plate III. Wet land at Richmond flat looking
north with the saddle to the Glen Gyle in left distance. The diversion
channel from the small lake in front of the dam (out of frame to
the right) to an intake structure in the distance across this flat
will be re-opened.
This area of the Parapara catchment
provides the opportunity for untilising the 160 metres of hydraulic
head which the Parapara River loses as it travels 2.3 km down the
lower gorge at an average fall gradient of 7%. As was identified
by the PHSC, a diversion route via a tunnel and fluming/pipeline
system through to the Glen Gyle catchment provides a cost effective
method of using this energy loss.
Water at up to 3m3 per second (subject to minimum residual flows) is proposed to be abstracted from the Parapara River
at Richmond Flat via a diversion channel leading from the small resevoir behind the existing dam at the head of
the Parapara Gorge at Richmond Flat.
The diversion channel will terminate at a control headworks at the northern side of this flat land formed behind the
Richmond Flat dam before entering the re-opened existing tunnel leading under the Glen Gyle Saddle into the
Glen Gyle catchment.
Water exiting the tunnel will be contained
in fluming and pipes on approximately the 185m contour of the true
right slopes of this catchment terminating at penstocks adjacent
to those of the PHSC and then generally down the stream bed of the
Glen Gyle to its confluence with the Parapara River, falling 130
metres to an automated power house constructed 100 metres approximately
downstream from the Glen Gyle confluence. A suitable site to erect
the 8m x 6m generator building exists on the true right bank of
the Parapara at the end of the legal road with the tail race returning
the water flow at river bed level.
From the generator building an ovehead 33kv transmission
line is proposed to cross the ridge to the right of the pinus radiata
trees in the medium distance in Plate IV to link with an existing
33kv transmission system in the Washbourne Creek area at the end
of the Parapara Valley Road.