Human Uses of the West Coast Marine and Coastal Environment
4.4 Other Coastal and Marine Resource Uses
 Figure 4.9 Prospecting and mining permits and licences extengin into or over the coastal marine area. Source: unpublished DOC data. |
4.4.1 Mineral, Aggregate and Driftwood Extraction
The general distribution and main areas of coastal (and some offshore marine) mineral deposits on the West Coast are mostly known as a result of past exploration and mining. These general areas give some (but not a full) indication of where future mining interests might lie, and so are broadly described here.
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The main coastal areas worked for gold were:
- Mokihinui Beach and Fairdown;
- Charleston;
- St Kilda;
- Brighton;
- Barrytown flats and terraces; and
- Darkies Terrace and North Beach [Cobden],
South of Ross the interglacial shorelines were mainly located west of the present day position and most of the deposits are modern beach placers, the major ones being:
- Saltwater Beach;
- Okarito Lagoon;
- Five Mile Beach; and
- Gillespies Beach16.
Ilmenite Sands
There has also been periodic prospecting interest in titanium-bearing ilmenite
sands in the northern and central parts of the West Coast, such as Karamea
North, Birchfield, Fairdown, Carters Beach, Nine Mile Beach, Barrytown and
Hokitika South 17.
Aggregate, Gravel and Stones
A number of businesses extract sediment materials such as gravel, aggregate
for concrete and decorative stones from beach foreshores and river mouths.
These activities are controlled primarily through resource consents issued
by the West Coast Regional Council.
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| Commercial operations such as this one at Blaketown take sediment materials from some intertidal beaches. Photo: T Hume, NIWA |
The Hokitika sewerage ponds outfall is an example of treated waste disposal in the |
Hydrocarbons
Offshore exploration for hydrocarbons has been undertaken in the Karamea area18.
Pounamu and Aotea Stone
The pounamu resource is owned and managed by Te Runanga o Ngai Tahu19.
Pounamu originates from several West Coast catchments such as the Arahura,
Hokitika and Cascade Rivers. Some coastlines in the vicinity of these catchments
are identified in the Pounamu Management Plan as areas open to public fossicking
for pounamu. The related resource of aotea stone originates from the vicinity
of the Makawhio and Mahitahi Rivers.
Driftwood
Driftwood is taken from most beaches for personal or commercial use (e.g.
firewood or art materials). The materials are typically taken from the foreshore
or from river mouth areas, but sometimes from the upper shore or from the
vicinity of coastal wetlands.
4.4.2 Waste Disposal
Disposal of solid and liquid waste onto coastal land and waters occurs on
parts of the West Coast. Point discharges are shown in the segment maps of
chapter 5. Sewage disposal plants have permission from the West Coast Regional
Council to discharge raw sewage and partially treated effluent at a number
of coastal settlements. Currently, all sewage effluent discharges from the
main townships of Greymouth, Westport and Hokitika are being upgraded. A number
of existing or closed rubbish dumps encroach onto or leach into coastal waters
(e.g. Westport).
Waste disposal from vessels is a prohibited activity within the territorial
limit.
4.4.3 Coastal Erosion and Flooding Response
High rainfall, dynamic rivers, an abundant sediment supply, and high energy
seas all contribute to erosion and flooding hazards on beaches and rivers
throughout the West Coast. These hazards can affect coastal developments such
as land, buildings and roads, as well as removing natural buffers such as
sand dunes and coastal forest. Such impacts may be exacerbated by the effects
of climate change, particularly if this leads to a rise in sea level and increased
storm surges.
The management of hazards, and their mitigation through protection measures,
planning and monitoring, is governed by local authorities enacting the Resource
Management Act (1991). To mitigate the effects of coastal erosion and flooding
on coastal settlements, some structures have been put in place within the
coastal marine environment.
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| Rockworks have been placed in response to sea and river erosion at several places along the coast including Bruce Bay(left) and Punakaiki (right). Photos: D Neale, DOC |
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Areas recently experiencing erosion and flooding hazards on beaches include:
Karamea, Granity, Westport, Woodpecker Bay, Punakaiki, Rapahoe, Greymouth,
Hokitika, Okarito and Bruce Bay.
Responses to coastal erosion and flooding hazards have included:
- the planting of dunes with exotic plants like marram and gorse, or native plants like pingao and flax;
- the construction of rock walls and protective bunds;
- the occasional artificial opening or widening of river or creek mouths and estuary channels; and
- planning provisions like setback zones and coastal hazard areas to control the development of coastal land and reduce the risk of coastal hazards.
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Ports like Greymouth Harbour are important to shipping and navigation operations throughout the region. Photo: S Nimmo. |
On the open coast, coastal protection works are the main type of structure.
Coastal protection works are usually built as rock revetments, but can also
comprise concrete walls and gravel bunds, or less formal modes of protection
such as truck tyres, sandbags and other dumped materials. Chapter 5 identifies
areas where coastal structures have been put into place in response to erosion
and flooding hazards.
4.4.4 Ports and Navigation
The river mouth ports of Westport and Greymouth are important commercial gateways
for these towns, providing facilities which cater mostly for fishing vessels
and the transport as cargo of local raw materials (eg, coal and cement). The
ports also provide facilities for recreational pursuits such as surfing, boating,
fishing and sightseeing. The river mouth ports of Westport and Greymouth are
two of only a few river mouth ports remaining in New Zealand.
Jackson Bay/Okahu has harbour facilities which include a wharf, boat ramp
and moorings. These are used by commercial fishers and increasingly by recreational
trailer boats and tourist boats. The wharf and surrounding area is also used
by sightseers and recreational fishers. A number of boat launching facilities
also occur in other locations, such as the Little Wanganui, Okari, Moeraki
and Okuru Rivers, but each is used for only small numbers of recreational
vessels or commercial fishers.
The Westport Harbour and bar are frequently dredged, with spoil being dumped
at a site to the northeast of the Buller River mouth. The Greymouth Harbour
wharf areas are dredged on a less frequent basis, with the spoil being dumped
in the vicinity of the Grey River mouth. The facilities of both of these ports
are mostly situated upstream from the designated coastal marine area of their
respective rivers.
Shipping and navigation occur throughout the coastal marine area. Shipping,
navigation and harbour facilities come under the management of Buller Port
Services within Westport Harbour limits (enclosed by a line extending between
Ngakawau River and Cape Foulwind) and the Greymouth Harbour Supervisor within
Greymouth Harbour limits (extending two nautical miles radius out from the
river mouth).
The exposed nature of the West Coast presents challenges for shipping and
navigation. The relative shelter afforded by some landform features (e.g.
some headlands, embayments, small islands and rock stacks) are well known
to many local fishers as anchorages or refuges in stormy sea conditions (identified
anchorage sites are listed in Chapter 5). River bars and channels are navigable
in the right conditions by experienced skippers of smaller commercial or recreational
vessels. Greater varieties of vessels use the three main West Coast ports,
or arrive from ports elsewhere such as Nelson and Bluff.
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Whitebait stands are one of the more common structures in the West Coast marine and coastal environment, such as these in the Okura River Estuary. Photo: P. Gerbeaux, DOC collection |
4.4.5 Marine and Coastal Structures
Because of the high-energy nature of the open coast, most structures in the
coastal marine area are in estuaries and river mouths. They include
- boat-ramps and launching sites;
- whitebait stands (present between late August - mid November);
- jetties;
- pipes (including waste disposal structures);
- flood and erosion works (discussed above);
- ports, ( as discussed above); and
- bridges.
Operating areas and area-based controls are specified and implemented under various conditions of consent, and these are discussed individually in more detail in Chapter 5. As well as the existing ports on the West Coast approvals have been given for operations at:
- the Solid Energy Ltd coal export facility near Granity;
- the Okuru Enterprises Ltd water export facility near Jackson Bay.
17 Braithwaite & Piranjo 1993 p.69
18 Kingett and Associates 1998
19 Te Runanga o Nga Tahu 1998