The Moutere Freshwater Management Unit has an area of 14,680ha and 524km of waterways, the largest being the Moutere River. These waterways flow to the Moutere Inlet. The Moutere Valley occupies the north-eastern flanks of the Moutere Depression and valley floor gravels hold very limited and localised shallow groundwater.
The Deep Moutere and the Deep Waimea Moutere Aquifers are covered separately in the Deep Moutere Groundwater FMU. These aquifers do not interact with surface water and have very slow recharge.
Only small remnants of the once extensive native forests and wetlands now remain in the FMU. Farmland occupies the majority of the FMU, with some areas of exotic forestry on the hills, horticulture on the coastal plains, and an increasing number of lifestyle properties.
Surface water in the catchment is limited and many smaller streams dry up during the warm, dry summer months. Demand for water comes from irrigation for crops and farming, with a small amount for domestic supply. Surface water in the FMU is considered to be over-allocated.
Due to poor stream habitat and high levels of modification, the Moutere River hosts a relatively smaller number of freshwater fish species and macroinvertebrates than would be expected for a catchment with so many low-gradient streams so close to the sea. Surface water quality is often poor, and in some cases is among the worst in the Tasman District particularly in relation to E.coli bacteria.
Challenges for this FMU include the water quality impacts of rural land uses, leaky septic tanks, intermittent forestry clearance in the upper catchment, and addressing poor stream habitat due to channel straightening and lack of riparian vegetation. This in turn leads to challenges to the health of the receiving environment of the Moutere River.
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 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.
All Moutere fresh waterbodies are natural, clean, vibrantly alive and unpolluted. Rivers and streams are fringed with riparian
vegetation helping to keep water temperatures low and aquatic life healthy. Wetlands have made a real comeback allowing for the
return of giant kokopu.
Note: Text in brackets are values from engagement round 2 that have been merged into the associated value.
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Other Community Values |
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The climate is sunny and mild and rainfall is one of the lowest across the FMU’s with mean annual rainfall of 1,250mm. 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 geology of the FMU 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.
The gravel is clay-bound with weathered greywacke derived sandstone, which results in quick run-off during rain and which dries in the summer leading to low water yield. A high southern underground basement rock ridge turns through from near Neudorf to Ruby Bay. The basement drops sharply to the east towards Richmond.
Most of the catchments are identified as Albic ultic soils which are prone to erosion. However, they usually have high clay content so these surface soils may increase the stability of the upper banks of waterways, where present. Some soils near waterways are waterlogged all year round and have slow drainage ability. In the lower river catchment an area containing brown soils have been mapped, which are the most common New Zealand soil type comprising mostly of clay minerals. These soils are likely to have a low erosion potential, due to the high clay content. Soils of the floodplains and low terraces are formed from recent alluvium and are generally productive and versatile.
The two principal surface waterbodies in the FMU are the Moutere River and the Tasman Valley Stream. The largest river in the FMU, 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.
Originally, vast areas of wetland would have occupied this FMU, particularly in lowland, coastal areas. However, most were drained to provide additional land for production and only a very small proportion now remain, mostly located near the coast, but some in upper parts of the catchment including the Moutere Hills.
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.
Forests dominated the FMU prior to human settlement with large areas of swamp on the valley floor in the Moutere. The alluvial plains supported towering podocarp forests and pockets of broad-leaved forests. Hill slopes had predominantly beech forest. 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, and progressed from seagrass and saline turf into rushes, sedges, harakeke and finally into forest.
The Moutere FMU is sparsely populated on the whole. Part of the FMU emcompasses a small part of the edge of Motueka township - Lower Moutere. Upper Moutere and Tasman are the other main villages.
Most properties source their water from private bores, with a proportion of properties in Lower Moutere accessing the Motueka Water Treatment Plant.
The Moutere FMU includes the habitat types of freshwater, forest remnant, estuarine, and saltmarsh.
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 the 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 this FMU, 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, koaro and redfin bully. The latter four species are rare in the 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 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 FMU. Koura are generally rare and as far as we are know kakahi (freshwater mussels) have not been found in the FMU. Pollution-tolerant Oxyethira, snails and Orthoclad flies are common or abundant at many sites.
Despite the dramatic species, biodiversity and habitat losses suffered with the removal of most native forest, there remain a wide variety of native plant species within the small native remnants of the FMU, including trees, grasses, sedges, rushes and ferns. 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.
A number of predominantly coastal threatened bird species are present in the FMU 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.
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.
The current state of water quality at the river sites in the Moutere FMU 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 Phosphorus, Water Clarity, Macroinvertebrate Community Index (MCI) and E. coli. 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.
Overall the surface water quality in the Moutere FMU 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.
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.
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 and surface and shall groundwater is considered over-allocated. Irrigators, the main water users, often rely on artifically created water storage earth dams to improve water supply security.
Shallow wells generally provide limited and unreliable supplies from groundwater.
The key freshwater challenges in the Moutere FMU are:
Moutere Catchment Investigation Final Report 2018.pdf (pdf 2.1 MB)
Moutere_Catchment_Restoration_Framework_FluvialGeomorphology_Final20200918.pdf (pdf 8.1 MB)
9309_TDC_Moutere Ecological District Report 02A_Update_DEC2015_WEB.pdf (pdf 2.6 MB)
Moutere Valley Groundwater: Nature and Recharge from Isotopes and Chemistry
The health of freshwater fish communities in Tasman District 2018.pdf (pdf 9.9 MB)
State of the Environment - River Water Quality in Tasman District 2015.pdf (pdf 33 MB)
2023 Water Quality Trends in Rivers of Tasman technical report.pdf (pdf 2.3 MB)
