The Abel Tasman FMU is mostly within Abel Tasman National Park. It also includes the catchments around Kaiteretere and Marahau – Holyoake and Otuwhero.
Many streams and small rivers flow from the mountainous interior of the Abel Tasman down to the coast, the largest of these being the Awaroa River. Apart from Marahau River, there is little information about the health of these rivers and streams currently. However, streams in native forest catchments are very likely to be healthy overall. Freshwater quality in the Kaiteretere and Marahau catchments is generally good, but there is evidence that fine sediment from disturbed land, e.g. forest harvest, and high rainfall, the highly erodible Separation Point Granite is carried along waterbodies into estuarine receiving environments causing degradation.
Water is generally sourced from surface water with the exception of the Kaiteretere water supply which comes from the Motueka Plains. Generally, the availability of water for drinking is not an issue, but a conservative approach is being taken to allocation.
Note: text in italics shows the sections of the vision specific to this FMU.
It is 2100, our waterbodies are healthy, connected and resilient where indigenous ecosystems and biodiversity are thriving, providing abundant mahinga kai, food and resource gathering and fishing. All waterbodies and their margins have high natural character and have room to move and adapt.
It is 2035, our land and freshwater management provides for our community’s social, economic and cultural wellbeing. People have access to safe, clean water for drinking, swimming, recreation and cultural uses.
It is 2040, sustainable and integrated land and water management practices protect the ecosystem health and natural character of our aquifers, rivers, lakes, springs and wetlands, and provides for our agriculture, tourism, commercial and industry sectors. Our urban development connects us to our backyard waterbodies.
It is 2055, our communities and livelihoods are resilient to our changing climate, floods and droughts. We have enabled use of renewable energy and water storage and our food producing areas continue to play an important role for local food security.
We all respect and take responsibility for freshwater health. We value the taonga we are protecting. Through collaboration and innovation we have adapted to new ways of doing things. We have restored, protected and maintained freshwater habitats and the quality and quantity of freshwater, enabling sustainable use for generations to come.
Our coastal streams and estuaries have high natural character and are clean and vibrantly alive with indigenous plant and animal life.
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Compulsory National Values |
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Other National Values |
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Other Community Values |
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Challenges for this FMU include:
Like most of the Tasman District, the Abel Tasman FMU experiences a mild climate and high sunshine hours. Coastal areas of the FMU are comparatively dry with an average of less than 1750mm of rain per annum, while the mountainous interior exposed to westerly winds is significantly wetter with up to 4000mm of rain per annum.
Geology within the Abel Tasman FMU comprises mostly of Separation Point granite. However, the Otuwhero, Holyoake and Upper Marahau catchments contain limestone and marble. Additionally, the Riwaka Complex comprises rocks high in magnesium and iron. Granite boulder and rock substrates exposed during a period of uplifting 200 million years ago dominate the Abel Tasman coastline. An overlying layer of limestone formed 30 million years ago has since eroded leaving isolated limestone outcrops at Taupo Point and Tata Islands.
The Marahau and Kaiteretere catchments are underlain by highly erodable Separation Point Granite (SPG) which has infilled valley floors in the lower reaches of the catchments with course granitic sand.
Soils developed from granite bedrock are relatively infertile, yet damp gullies just above sea level support rich forest.
Many streams and rivers flow generally from the hills and mountains in the west, towards the coast. The largest of these is the Awaroa River (3933 ha catchment) followed by Marahau (2575 ha) and Otuwhero (2162 ha).
Other water bodies along the Abel Tasman, from south to north, include Tinline Stream, Simonet Creek, Lesson Creek, Torrent River, Falls River, Tregidga Creek, Kilby Stream, Huffam Stream, Awapoto, Tōtaranui Stream, and Kaikau Stream.
Water bodies outside of the national park include the Marahau River, Otowhero River (approximately 10 metres wide), Kaiteretere Stream (2 – 3 metres wide) and Holyoake Stream. These all have stable base flows and have beds dominated by granule and course sand sediment.
The accumulated sandy sediments in the lower valley and coastal plain of the Marahau catchment support a shallow unconfined aquifer around 1 to 2 metres below ground level. Recharge is from rainfall and some leakage from the Marahau River and other small creeks. Localised and limited groundwater occurs in the sandy sediments that underlie the valleys that drain the granite geology within this FMU.
The unconfined aquifers extend out into the foreshore and are hydraulically connected to the sea, meaning bores close to the coast are vulnerable to sea water intrusion from over pumping.
Most of the estuaries in this FMU are shallow, enclosed lagoon type systems that almost completely drain at low tide. The Awaroa Inlet is the largest estuary at 289 ha with almost all the catchment in native Forest. The Torrent Bay estuary is reasonably small at 38 ha and is unusual in that it has a very popular walking track running across it. The Kaiteretere Inlet is a small sized (18.9ha) estuary with minimal freshwater input. Part of the saltmarsh in this estuary has been lost due to changes in the hydrology.
Otuwhero Estuary is a 95 hectare estuary with 34 ha of saltmarsh and 1 ha of seagrass. Just under half the catchment is in plantation pine forest, with some of the most erosion prone areas replanted in permanent manuka canopy from 2017-23. It has high freshwater input and high ecological value (including an adjacent freshwater wetland). However there was a large build up of mud as a result of land disturbance and impacts from the 2018 Ex-Cyclone Gita and Fehy. Prior to this it was considered to be in a healthy ecological state.
Marahau estuary is small at 39 hectares in size. It is open, dominated by seawater and bordered by extensive saltmarsh (22 ha) and seagrass. There are considerable commercial vehicle movements occur over this estuary and seagrass habitat, and this is controlled by a resource consent. Forest (primarily native) makes up 81% of the catchment and 7% is in pastoral land use. In 2012 it was considered to be in good health.
Most of the estuaries are dominated by sand, but areas of soft mud are also present.
Prior to European settlement, Māori occupied areas all along the coastline of the FMU going back around 800 years, establishing small settlements, pa sites, and food growing areas. European settlement of the Abel Tasman coastline began in the 1840's. Early attempts at farming along the coast failed largely because of low soil fertility and subsequently the population declined. In 1942 the Abel Tasman National Park was created and now encompasses a total of 24,500 ha.
Today, native bush occupies most of the FMU. Sheep and beef farming, pine forestry, coastal communities (including at Marahau and Kaiteretere), and lifestyle blocks occupy a very small portion of the FMU, outside the National Park and are the dominant land uses in the Marahau and Kaiteretere catchments. The FMU is also a very popular tourist destination and numbers of visitors swell considerably over the summer months.
Fourteen native fish species have been recorded within Abel Tasman fresh water bodies, including threatened migratory galaxiid species, such as short-jaw, and giant kōkopu, kōaro and inanga. Banded kōkopu (not threatened) are often seen in small pools, even during the day.
Almost all of the park was once forested. Red beech forest covered the greatest area. Nearer the coast was black beech and hard beech. More fertile parts had podocarp/broadleaf forest. Considerable stands of lowland alluvial forests once existed in Awaroa, Totaranui, Mutton Cove, and Whariwharangi. Kahikatea-dominated swamp forest also once occurred at the mouth of the larger streams, particularly the Awaroa and Marahau.
Black beech continues to be the natural cover of the dry ridges and headlands close to the sea, with hard beech further inland where more moisture is available, along with Kanuka and manuka. Lowland alluvial forests have disappeared, but are now in the slow process of regeneration. Ferns, kiekie and supplejack remain. Only around 5% of swamp forest remains.
Several native bird species have disappeared including robins and mohua. korimako, pīwakawaka, kererū and tui are now the main forest birds. Around the beaches, estuaries and wetlands, pukeko and weka are common.
It is estimated that about 40% of freshwater wetlands in the FMU have been lost to drainage for farmland. However, some of these such as at Hadfield's Clearing at Awaroa are being restored.
Marahau River is the only waterway in this FMU that is sampled regularly, although coastal bathing sites are monitored and are an indicator of freshwater health. Water quality is very good in the Marahau River and it appears to be recovering from the ex-cyclones in 2018. Relatively low cover of periphyton was recorded, except during the couple of years following ex-cyclones Gita and Fehy in 2018.
During monitoring in 2015, the concentration of disease-causing organisms over a range of flows in the Kaiteretere Streams was found to be low.
Kaiteretere Beach has the highest use of all the beaches in Tasman District. It is suitable for swimming over 88% of the time, but not after heavy rain where spikes of E. coli have breached national guidelines.
Water quality in the Marahau aquifers is generally good. However, the shallow unconfined nature of the aquifer is such that it is vulnerable to contamination from surface activities (in particular onsite wastewater disposal and livestock farming). In addition, elevated iron and manganese concentrations are known to be present in parts of the aquifer. As noted earlier localised groundwater occurs in the outwash sediments in the valleys that drain the granite geology. Groundwater quality in these sediments can be variable and at times irony.
The main water use in the FMU is for drinking water from the settlements at Marahau and Kaiteretere, and by Department of Conservation campgrounds at Totaranui. Kaiteretere water supply comes from bores on the Riwaka side of the Motueka River and is pumped to Kaiteretere.There is also community water supplies in Torrent Bay and Awaroa from nearby creeks to service the residential dwellings. The water takes within the national park are from small creeks for hut supplies and are gravity feed.
There are allocation limits for some of the smaller coastal catchments near the Abel Tasman National Park to help reserve water for potential future water needs of the community and to provide some guidance for potential water users.
State of the Environment - River Water Quality in Tasman District 2015.pdf (pdf 33 MB)
Marahau Groundwater Aquifer - brief summary.pdf (pdf 124 KB)
Kaiteriteri Estuary Martin Farm Road Embayment - Synoptic survey FINAL 2023-03.pdf (pdf 8 MB)
Rules for Water Takes, Damming or Diversion - 2020-12-19.pdf (pdf 434 KB)
Abel Tasman National Park information
Coastal Risk Assessment Monitoring Report August 2012.pdf (pdf 6.5 MB)
Intertidal and Shallow Subtidal Ecology Abel Tasman National Park
