The Motueka FMU includes the Motueka River and its tributaries and the Riuwaka catchments that drain to Te Tai o Aorere / Tasman Bay. The Motueka River arises from Maungakura/Red Hills in the south-east. Its major tributaries are the Motupiko River from Te Tiritiri o te Moana/Southern Alps in the south (near St Arnaud) and the Wangapeka River in the west. Many karst spring streams arise in the west between Mt Owen and Tu Ao Wharepapa /Mt Arthur.
The extensive mountainous areas of the FMU remain largely in protected native forest, but there are some areas of exotic forestry. Conversely, the Motueka Valley and out to the coast have been cleared of forest and land is mostly pastoral. Motueka township is the largest town within this FMU, followed by Tapawera further to the south. The climate is generally sunny and mild, with rainfall increasing with elevation.
Water quality is good overall, with some examples of excellent habitat and very low levels of contaminants in a number of the larger rivers. The natural character and trout habitat of the Motueka River is protected by a Water Conservation Order. However, there are increasing nitrate levels on the Motueka River and sedimentation is a major issue which affects stream beds and aquatic habitat. This in turn impacts the receiving environments of the Motueka Estuary and Tasman Bay/Te Tai-o-Aorere. Like with other FMUs, some smaller, modified streams in pastoral catchments have elevated nitrates, water temperature, and E.coli concentrations.
Water abstracted from this FMU supports food and beverage production on the Plains, along with drinking water for town water supplies. There is water available in a number of zones within the FMU but several are fully allocated. Some of the Motueka/Riuwaka Plains areas face significant water shortage and allocation problems during the summer months. Although groundwater quality is good, it is unsecured which poses a health risk if used for drinking water.
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By 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.
In progressing towards these goals, Ngā Iwi o Te Tauihu, Ngāti Waewae and communities are enabled to exercise kaitiakitanga and guardianship. Ngāti Kuia and Rangitane o Wairau maintain their whakapapa, historical connections and kaitiaki role with Pakohe. We all respect and take responsibility for freshwater health. We value the taonga we are protecting. Through collaboration and innovation we adapt to new ways of doing things. Our land and freshwater management provide for our community’s social and cultural wellbeing. We restore, protect and maintain freshwater habitats and the quality and quantity of freshwater, enabling sustainable use and appreciation for generations to come. Freshwater bodies and ecosystems located within Department of Conservation lands are maintained in their natural state.
This long-term vision will be achieved by stepping through the milestones below.
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The Motueka-Riuwaka-Moutere FMU faces a wide range of environmental pressures including degraded water quality, habitat loss, and land use impacts that require the need to protect the natural state of important rivers while providing safe drinking water, sufficient irrigation supplies and abundant angling opportunities. Key concerns include high E.coli, sediments entering coastal areas and high nutrient levels in lowland streams. Stopbank protections, improved wastewater discharge practices, access to mahinga kai and improved flood management are all desirable outcomes for this FMU. For a list of all community and iwi identified challenges and issues view the Motueka Issues and Challenges Set – October 2025 (pdf 69 KB).
The current state of water quality at the river sites in the Motueka catchment has been evaluated using the National Objectives Framework of the National Policy Statement – Freshwater Management. Under this framework, key attributes to assess water quality are Total Ammonia, Nitrate-N, Dissolved Reactive Phosphorous, Water Clarity, E.coli, and Macroinvertebrate Community Index (MCI). Each water quality attribute is ranked from A through D (or A through E for the E.coli attribute) with the D (or E) band representing poor water quality at each river site. Trends over 5 and 15 years are also assigned based on five classes from very likely improving to very likely degrading.
Water quality is generally good across the catchment. For example:
However, there are some streams and rivers, and results that are cause for concern, including:
The current state of water quality at the river sites in the Moutere catchment has been evaluated using the National Objectives Framework of the National Policy Statement – Freshwater Management.
Overall the surface water quality in the Moutere catchment is poor, particularly in the lower part of the catchment, with the main waterways exhibiting water quality amongst the poorest in the Tasman District for some parameters, but showing some signs of improvement.
Concentrations for E. coli and MCI do not meet national bottom lines on the Moutere River (they are both in Band D). Fine sediment also clogs the river bed as a result of bank erosion and historical forestry clearance, land development for housing and horticultural practices. Although Nitrate-N is within the B Band, algae growth is prevalent likely due to nutrients bound to deposited sediment. However, water clarity is relatively good, and E. coli and macroinvertebrate levels may be improving, pointing to possible improvements in land use management in the catchment.
The Tasman Valley Stream near Tasman village shows high E.coli concentrations which have been a major problem in this stream for some time and do not meet national bottom lines (Band D). Cattle numbers were reduced considerably from the catchment in 2015, so these levels are likely because of failing septic tank systems. Dissolved reactive phosphorus and macroinvertebrates also do not meet national bottom lines, and while Ammonia concentrations are in Band A, they are very likely degrading over the last 5 years. Water clarity in the stream however is good.
Overall, the groundwater quality in the Motueka/Riuwaka Plains is good with no significant changes to the majority of water chemistry parameters over time. The majority of the parameters tested for were well within the Drinking Water Standards for New Zealand (DWSNZ) for both the health significant and aesthetic factors. This includes:
However, the aquifer underlying the Motueka / Riuwaka Plains that water is sourced from is unconfined/semiconfined (leaky). Because of this it does not meet the Drinking Water Standards New Zealand (DWSNZ) definition for secure groundwater. This means that despite the good quality of the groundwater currently, there are health risks because of the potential for contamination.
In addition to this, because many bores are old, they are often not sealed at ground level they have risk from the local surrounding e.g. rubbish and chemicals stored nearby. Some are located in low-lying areas or near stormwater drains, increasing risk of localised runoff contamination.
In the Moutere catchment the clay and silt-bound reworked gravel infill in the valley floor results in limited, shallow groundwater supplies recharged from local rainfall and some contribution from adjacent local streams. Shallow groundwater is unreliable and even local small supplies are variable spatially with many areas being considered dry.
NB: There is a separate FMU for the Deep Moutere Groundwater Aquifer.
Coastal water is likely to be in generally good health given the amount of dilution from clean seawater and relatively good water quality in the larger rivers. However, the detectable sediment plume from the Motueka River covers an area of sea bed of about 180km2 with plume-affected nickel concentrations up to six times higher than guidelines. Additionally, areas around Port Riuwaka are not considered swimmable for over 20% of the time. This may be due to discharges from live-aboard boats or cross-connections at dwellings.
The aquifer system underlying the Motueka-Riuwaka Plains is a primary source of water for irrigation, industrial, community, domestic and stockwater supplies in the FMU. Irrigation is the largest water user.
Both the Motueka township and the nearby Riuwaka settlement provide reticulated community water supplies from the aquifer system with one-third of the houses in Motueka connected to the Tasman District Council water supply. Council have recently opened a water treatment plant that now provides good quality chlorinated water to reticulated users.
There is an estimated 2,000 private (shallow) domestic bore water takes in Motueka, used for both domestic and commercial/irrigational purposes. This makes Motueka the largest town in New Zealand that doesn’t have a fully reticulated (networked) supply.
The Mid Motueka River (Woodmans to Wangapeka) has reasonable water allocation potential.
The Upper Motueka River (upstream of Wangapeka to Motupiko) and Motupiko catchment is almost fully allocated and there is demand for more water.
The Riuwaka groundwater zone is fully allocated and the Umukuri groundwater zone is fully allocated. In the King Edward zone, the total allocation appears to be under the limit, but in this zone an over allocation for commercial use types is compensated by the lack of use of the reservations for public and private community supplies and institutional/recreational takes. All other zones have room for further allocations.
The Moutere River at Riverside varies between a low monthly annual flow in January of 180 l/s, and its highest in August at 2,300 l/s. Many headwater streams dry up in summer, and demand for water is often greatest when there is the least water available. No water permits have been granted for surface water in this FMU since the late 1980’s. Surface water and shallow groundwater is considered over-allocated. Irrigators, the main water users, often rely on artificially created water storage earth dams to improve water supply security.
Shallow wells generally provide limited and unreliable supplies from groundwater. Water for domestic use often relies on capturing and storing rainwater in large tanks.
The Motueka catchment has a generally warm and mild climate. Mean annual sunshine hours (2,407) are among the highest in New Zealand. Frosts can occur between April and October and snow can fall during all months at higher elevations.
Rainfall is strongly seasonal and varies significantly with topography. The mountainous northern areas are characterised by relatively high rainfall, of about 3,500 mm / year. The southern areas including the settlements of Motueka, Tasman Upper Moutere, Lower Moutere, Brooklyn, and Riuwaka, by contrast are relatively dry, with rainfall of around 1,000 mm / year.
In the Moutere catchment extreme rainfall events are infrequent but these have resulted in some change to river channels in the recent past. November to February can be experience periods of drought with corresponding reductions in river flows and water availability.
The Motueka FMU is geologically very complex compared to many other South Island catchments.
Ultramafic and old sedimentary rocks form the mountains at the south-western end of the Richmond Range in the headwaters of the Motueka. The ultramafic rock has high Iron, Chromium and Nickel levels. In this special mineral belt, where the soil repels most native trees, a unique shrubland community has evolved.
The complexity of landforms, climate and sedimentary and igneous rock types such as marble, limestone, greywacke, argillite, diorites, gabbros, granite, mudstone and sandstone have resulted in a wide variety of soils including deeply weathered and highly erodible Separation Point Granite.
The geology of the eastern side of the catchment is defined by the Moutere Depression, an area of comparatively low-relief river valleys situated between the Tasman Mountains in the west and the Richmond Ranges to the east. The Moutere Depression is about 23 km wide and extends 65 km from the headwaters of the Motueka Catchment to Tasman Bay. Voluminous gravels are preserved in the depression and reach up to >600 metres deep under the Moutere Valley, which has been incised by the Moutere River. It is underlain by much younger alluvial sediments of the Moutere gravels. This is a thick (0.7 km near Tapawera), deeply weathered gravel, dominated by greywacke sandstone fragments, within silt and clay.
The complexity of landforms, climate, and rock types in the Motueka Catchment results in a wide variety of soils. Land alongside the rivers and a large area near the coast including the township of Motueka comprise very versatile, high quality soil formed on alluvium. Soils of the upper catchment are often prone to erosion when cleared or disturbed, and are of low fertility.
The Motueka River has a large, predominantly mountainous and hilly catchment of 2,076 km2. The river originates at an altitude of 1,800 metres and flows for 110 kilometres along a narrow valley below Tapawera to follow the foot of the Western Nelson Range (Arthur Range/Wharepapa) towards Tasman Bay/Te Tai-o-Aorere. It has a mean flow of 58,560 litres/second (l/s), a median flow of 33,950 l/s, and a mean annual low flow of 10,216 l/s at Woodstock. The river is prone to high flows and some large floods and extended periods of low flow during summer.
The Motueka River is braided in the approximately 10km reach below the gorge, through Kohatu and to the Wangapeka River However, its natural path has been narrowed and straightened in its lower reaches, with stopbanks installed on the Lower Motueka River up as far as Peach Island, primarily to protect the Motueka township and surrounding infrastructure from flooding.
The western tributaries of the Motueka River, notably the Wangapeka and Baton Rivers, originate in the Arthur and Owen Range and have higher flows similar to the rivers in the higher rainfall Golden Bay area. They contrast greatly with the small rivers such as the Dove and Stanley Brook rivers originating in the Moutere Hills, as parts of these can dry up completely in summer.
The Riuwaka River has a 105 km2 catchment that flows into Tasman Bay three kilometres north of the Motueka River, and also includes a number of tributaries. For part of its journey, the river flows underground through limestone caves, returning to the open air at Te Puna ō Riuwaka / The Riuwaka Resurgence.
The Moutere River has a catchment of 146 square kilometres. The river flows from the Upper Moutere Hills through rolling hill country along the Moutere Valley, and flows into the northern end of the Moutere Inlet just to the south of Motueka. The river has been highly modified from its original form particularly the lower reaches which were dug as a very straight ‘ditch’ in the 1850s and 1860s when wetlands were drained to make land available for farming. Many of the tributaries of the Moutere River have been straightened or modified in some sections, yet some still retain areas of sinuosity (meander) and riparian vegetation.
The Tasman Valley Stream has a small, predominantly rural catchment area of 8.5km2, flowing into the Moutere Inlet at its southern end. It has several reaches with natural meander and small remnant riparian forest patches but has also been modified in parts. Tributaries of the Tasman Stream include Horton Valley Stream, Baldwin Creek, Mamaku Valley Stream, and Williams Road Stream.
The Waiwhero wetland is a large (16ha), natural wetland in the FMU. There are other small but ecologically significant areas of wetland found at the coast and scattered throughout the FMU. Several artificial wetlands have recently been and are being created beside the Motueka river in areas where river gravels have been extracted. Only 2% of the original wetlands of the Motueka-Riuwaka coastal outwash plains remain.
Within the Moutere catchment, particularly in lowland, coastal areas there were originally vast areas of wetland. However, most were drained to provide additional land for production. Now only a very small proportion remain, mostly located near the coast, but some in upper parts of the catchment including the Moutere Hills.
Groundwater in the Motueka Plains groundwater system is contained within alluvial gravels (known as the Motueka Gravel Aquifer) forming the coastal delta of the Motueka and Riuwaka rivers. The Motueka gravels are thinnest (approximately 6m) at the inland margins of the plains, and thicken to 30 metres in the central plains area, where they are the cleanest and most permeable.
The catchment to its west includes the nationally recognised Mt Arthur karst cave system. A high-yielding aquifer comprised of three interlinked layers underlies the central part of the Motueka Plains.
The aquifer system is highly interconnected with the Motueka and Riuwaka rivers. A large proportion of aquifer recharge is sourced from these rivers. Additional water is supplied by rainfall and irrigation recharge across the plains. Groundwater exits the aquifer system by subsurface flow into Tasman Bay, into springs near the coast, into rivers, or via groundwater pumping.
NB: There is a separate FMU for the Deep Moutere Groundwater Aquifer.
The Motueka – Riuwaka Delta, is made up of four estuaries which are described in more detail on this page.
The Moutere Inlet is the receiving environment for these freshwater bodies and is a medium-size (764 ha), shallow, well-flushed tidal lagoon that discharges to Tasman Bay via tidal entrances at Port Motueka and Kina Peninsula (at either end of Jackett Island). The estuary almost completely empties at low tide. Learn more about the Moutere Inlet.
Tall forests are believed to have originally dominated much of the FMU, with podocarp species in the fertile lowland areas, pockets of broad-leaved forests and varying beech species elsewhere. Large areas of swamp existed on the valley floor in the Moutere. A band of coastal scrub is likely to have occurred along the coastal margin. Along the coastal bluffs and fringing the estuaries, ngaio, cabbage tree, kōwhai and totara would have been common. Swamp areas were dominated with harakeke, raupo and purei. The estuaries were alive with wetland birds, fish and invertebrates. Seagrass and saline turf progressed into rushes, sedges, harakeke and finally into forest. Alpine tussock grasslands would have covered the FMU above an elevation of about 1200–1400 metres.
The Motueka River was once free to meander and braid, to alter course and flood widely across the plains. Such a dynamic environment would have produced a mosaic of forest, scrub, shrublands, gravelfields, braids and wetlands, with gradients between them, and successionary phases of renewed forest growth within the immediate riparian environs.
The Motueka Plains were cleared of forest by Māori initially, other than for Te Maatu, ‘the Great Wood’ of some 350 ha or so of podocarp-rich forest that ran south-west in a band from what is now Motueka township to the Motueka River. Most of the subsequent forest clearance occurred in the mid-to-late 1800s with European settlement.
The main land uses in the Motueka Catchment today are:
Horticulture (pipfruit, berryfruit, hops, vegetables) occupies a small, but expanding, area on the river flats and terraces and is a major water user. Most crops are irrigated from surface or groundwater during the summer.
Motueka is the significant urban centre in the catchment with a population of around 8,000. There are smaller settlements at Riuwaka, Brooklyn, Tasman, Lower Moutere, Upper Moutere, Ngatimoti, Dovedale, Tadmor and Tapawera.
Many properties source their water from private bores, with a proportion of properties in Motueka and Lower Moutere accessing the Motueka Water Treatment Plant.
Motueka Catchment
The Motueka catchment has a moderately diverse range of native freshwater fish species. It contains 20 of New Zealand’s 51 native fish species, including galaxiids, bullies, and eels. There are also five estuarine and marine fish species in the lower reaches, essentially black flounder, kahawai, yellow-eyed mullet, stargazers and cockabully.
Of the native fish species in Tasman, more than half (currently 12) are listed as At Risk or Nationally Vulnerable by the Department of Conservation. This high proportion of species with declining populations is largely due to broad-scale land use changes which has led to the degradation of fish habitat in waterways.
Macroinvertebrate communities are diverse (at least 119 taxa dominated by caddisflies, true flies, mayflies, and stoneflies) and generally dominated by species characteristic of unpolluted habitats, unmodified streams, and high aquatic habitat quality.
There is a Water Conservation Order over the Upper and Middle Motueka River, based on nationally significant trout fishery and high natural and intrinsic values. The Motueka and Riuwaka rivers contain important trout fisheries.
The Motueka River is used by river-nesting birds such as Oystercatchers, Black-billed gulls, Banded Dotterels and Pied stilts. This reach is used for nesting by Black-fronted terns, Banded dotterel, and South Island Pied Oyster-catcher. The threatened blue duck has been reported from the Pearse, Baton, Wangapeka and upper Motueka rivers.
Moutere Catchment
In the Moutere, streams have varying levels of native species habitat and ecological health depending on the level of stream channel modification, bank erosion, riparian planting and surrounding land use type and land use practices. Given this catchment’s proximity to the coast and low elevation, there is high potential to improve fish and invertebrate diversity.
About 17 species of native fish have been found in the Moutere catchment, with between three to seven species of native fish in particular reaches depending on the quality of the freshwater habitat, but would historically have supported many more. Species found now include inanga, smelt, long fin and short fin eel, and common and giant bully, banded kokopu, torrentfish, kōaro and redfin bully. The latter four species are rare in the Moutere catchment. The catchment used to support reasonable numbers of giant kokopu, but these have not been found recently. High stream temperatures and low dissolved oxygen in summer are likely reasons for their absence.
Macro-invertebrate diversity in the Moutere catchment is very low also with mayflies and caddisflies making up a small percentage at most sites. Deleatidium, NZ’s most common mayfly, is reasonably sensitive to pollution and is rare or absent in over 60% of streams in the in Moutere catchment. Koura are generally rare and as far as we are know kakahi (freshwater mussels) have not been found here either. Pollution-tolerant Oxyethira, snails and Orthoclad flies are common or abundant at many sites.
The only natural lakes are very small and alpine/sub-alpine within the conservation estate e.g. Luna Lake in the upper Wangapeka catchment.
The distribution and abundance of native fauna have been severely affected by the removal of much of the forest from lowland areas of the Motueka Catchment. McKee Memorial Scenic Reserve protects coastal slope titoki-(matai) forest. Large kahikatea are confined to a treeland at Upper Moutere. These areas support a range of indigenous birds, with piwakawaka, tui, and korimako the most common. There are still large upland areas of native forest with a wide variety of birds and other animals, but few examples of large tracts of lowland forest or unmodified freshwater and coastal wetlands.
The area of the west-bank tributaries around the Arthur mountains retains more of its original vegetation, bird and animal life than other areas. Formerly the area would have been almost entirely covered in forest. The alluvial plains and terraces supported towering podocarp forests and pockets of broad-leaved forests in sheltered lowland sites. While the low hills contained mixed forest of black beech, hard beech, rimu, totara, kāmahi, tītoki and tawa. Along the coastal bluffs and fringing the estuaries, ngaio, cabbage tree, kōwhai and totara would have been common.
Black beech and kahikatea are dying out across the catchment. Silver beech, rimu, pokaka, kowhai, tarata, manatu and narrow-leaved lacebark are all scarce or rare.
Forest sites contain a wide variety of birds (including kākā, yellow-crowned parakeet, falcon, kiwi, blue duck, fernbird, robin, rock wren, kea, long-tailed cuckoo) and are also notable for large land snails (Powelliphanta).
A number of predominantly coastal threatened bird species are present in the catchments including the karearea/New Zealand falcon, matata/South Island fernbird, torea-pango/variable oystercatcher, kareke/marsh crake, pereru/banded rail, kawau/black shag, kawaupaka/little shag and kotukungutupapa/royal spoonbill.
Historically, estuarine ecosystems that are the receiving environment for the freshwater system provided habitat for a diverse range of birds, reptiles and invertebrate fauna in densities and diversities unimaginable today.
However, all five estuaries (Ferrer Creek Estuary, Motueka River Estuary, Motueka Estuary, Moutere Inlet and the Riuwaka Estuary) have suffered from extensive historical habitat modification, in particular the removal of salt marsh, reclamation of estuary areas, and the interruption of natural flow regimes. This has significantly reduced habitat diversity, and is continuing to do so.
Currently the amount of mud-dominated sediment in Moutere Inlet is very high and is the main ecological pressure on the estuary. Heavy discharges of sediment from horticultural land in catchments draining to the Moutere Inlet was common in the 1950s through 70s and again in 2007-08 with large-scale conversion of pine forest to other land uses.
Despite this, along with extensive historical habitat modification, the Moutere estuary retains significant ecological value, and is a valuable nursery area for marine and freshwater fish, has large shellfish beds, and is important for birdlife.
Saltmarsh has been historically highly modified and reduced in area. It is comprised mainly of rushland (searush, oi oi and sedgeland) and low growing salt and herbfield species such as glasswort and sea blite.
Despite these past changes, all five estuaries retain significant ecological value and the Department of Conservation regards the Motueka delta as being of national importance. The estuarine and coastal area around the mouth of the river is important for a range of fish and shellfish, while Tasman Bay supports a wide variety of plankton, benthic organisms and fish. The Motueka Sandspit is formed with sand and gravels of the Motueka River and is internationally important habitat for kuaka/Eastern Bar-tailed Godwits, torea-pango/Variable Oystercatchers, torea/South Island Pied Oystercatchers and Banded Dotterels and nationally important for Ruddy Turnstone. Scallops, oysters, mussels, cockles and snapper are important commercial and recreational fisheries.
Salt marsh is relatively extensive in the estuarine area from the Riuwaka River to Motueka and made up 69ha (28.2% of the intertidal area). An estimated 60-75% of the historical salt marsh cover was lost prior to 1947 due to drainage, reclamation and land clearance. The muddiest estuaries were Ferrer Creek and Riuwaka, whose extent of mud-dominated sediment (24% and 18%, respectively) was high in both a regional and national context. Motueka River and Motueka Estuary had very little mud (<2%). Nuisance macroalgae was scarce. Seagrass is present from the Riuwaka estuary towards Tapu Bay.
