This includes the Waimea River (and its tributaries the Wairoa and Wai-iti Rivers), the smaller coastal catchment areas to the west of the Waimea Plains, and the urban streams of Richmond. The Waimea FMU is underlain by a number of subsurface aquifers under the Waimea Plains.
The majority of the native forest and associated habitat that once covered the Waimea Plains has been removed. Land on the Waimea Plains is highly productive, is predominantly used for horticulture and farming, and is irrigated. Richmond is the main population centre and it is growing rapidly. The upper catchment retains a greater degree of original forest, along with exotic forest.
There is variable relief across the FMU. The Waiora and other rivers and streams in the east of the FMU rise in the mountainous terrain of the Richmond Ranges. Whereas the Wai-Iti River and the coastal catchments are situated in the lower relief terrain of the Moutere Depression.
Water quality is generally good in upper parts of the catchment where natural land cover remains. However, rivers including the Waimea and Wai-iti flow through intensively used land in lower parts of the catchment and as a result water quality problems arise. Small lowland streams make up a large proportion of the stream network in the FMU and are often in a poor state. Aquatic habitat is often poor in streams and rivers adjacent to developed land. This can be attributed to straightened streams, sedimentation, insufficient differences in water depth, lack of riparian tree cover, and lack of substrate such as wood. This is mostly a historical issue and a lot is due to the river corridors being narrowed and is disconnected from the wider flood plain.
Nitrate concentrations have historically been an issue in groundwater in parts of the lower plains and continue to show elevated levels. This in turn causes poor water quality in coastal spring fed streams.
Demands from irrigation and population growth, and historical over-allocation, means that water on the Waimea Plains is significantly overallocated and unreliable, particularly in the drier months. There are risks of saltwater intrusion into aquifers along the coast, and there is a need to bring water use back to within sustainable limits. The Waimea Community Dam should alleviate this issue, and this dam is planned to come on line in 2024.
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 and their braids, lakes, springs and wetlands, and provides for our agriculture, tourism, commercial and industry sectors.
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, including the Waimea Plains, 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 urban communities and productive land users protect the interconnected system of waterbodies that feed into the Waimea Inlet and Tasman Bay. The nitrate levels are improving along with the health of the aquifers and spring-fed streams. Urban stormwater is kept clean or treated before entering streams. The Waimea Inlet is vibrant and healthy, teeming with bird life.
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The climate on the Waimea Plains is sunny and sheltered, with very warm summers and mild winters. It is cooler and wetter to the south and at higher altitudes. Rainfall ranges from 900 – 2250mm per annum, with higher rainfall in the eastern ranges.
Future predictions due to the impacts of climate change indicate rising temperatures and resulting reduction in frost days, which will affect the setting of fruit and potential land use on the Plains.
The Waimea Plains lie on the eastern edge of the Moutere Depression, a 30 km wide system of low hills and valleys between the Tasman Mountains and the ranges of east Nelson. The valley floor is underlain by the extensive Plio-Pleistocene clay-bound Moutere Gravel. This is greater than 1000 metres deep on the Plains near Richmond. Towards the coast the Moutere Gravels have been incised and overlain by more recent alluvial (river deposited) gravels and sands – the Hope Gravels, Appleby Gravels and Stoke Fan Gravels. To the west of the Waimea Plains, the Moutere Gravels form the low hills that run from the Spooners Range in the south to Mahana in the north.
The Waimea/Flaxmore Fault system marks the eastern edge of the Moutere Depression, with the Richmond Ranges being uplifted on the eastern side of the fault. The geology of the Mt Heslington and the Barnicoat Ranges is notable for the Dun Mountain Ophiolite Belt (the ‘mineral belt’), most extensively expressed in the Red Hills. This is a mix of sedimentary, ultramafic (igneous rock with a very low silica content) and volcanic rocks.
Soils within the Waimea Plains are generally highly productive but do exhibit variability in their versatility for production. The two largest areas of versatile soils are the Ranzau soils to the south-west of Richmond and the Waimea soils to the west and north of the Ranzau soils. Soil water-holding capacity has been found to be the greatest determinant of nitrogen losses (higher than irrigation). Of the local soils, Ranzau soils have the lowest moisture holding capacity, with increasing moisture holding capacity associated with the Waimea and Wakatu soils, and then the Richmond soils. Workability and water logging can be an issue on Waimea soils.
The Wairoa River flows from a mountainous catchment in the Richmond Ranges of approximately 460km2. The Wairoa exits the ranges at the Wairoa Gorge. The tributaries of the Lee and Roding Rivers, with a combined catchment of 243km2, join the Wairoa River from the Lee Valley. The Wai-iti River, which flows from a catchment of 250km2 is situated in the comparatively low-lying Moutere hills to the west and joins the Wairoa River in the central portion of the plains. At this point the river becomes the Waimea River. The original name “Waimeha” means “brackish” or “insipid water”. This name relates to the nature of the river as it passes swamp and mudflats on its way to Tasman Bay. The Waimea River then flows to the Waimea Estuary near Best Island. The Waimea River recharges groundwater, and can experience very low flows in its lower reaches over summer and completely dried up in the drought of 2001.
In addition to these larger rivers, there are many smaller streams in the catchment. Pearl, and Neimann Creeks are two small coastal groundwater emergent springs. Reservoir Creek begins in the Barnicoat Range and ends at the Waimea Estuary at a point near the edge of Richmond, bordering Stoke.
Swamp forest and harakeke wetlands originally covered much of the Waimea plains from the edge of the estuary and extended up the Waimea Valley towards Brightwater (all within the Motueka Ecological District). Only 2% of natural wetlands remain, with small wetlands on Rough Island and along mid-upper parts of the Wairoa River being some of the best examples. There have been a few wetlands constructed such as Challies Island and Waimea Delta.
There are no natural lakes in the Waimea FMU, and even the few alpine tarns are very small.
The major aquifers of the plains are the Appleby Gravel unconfined aquifer (AGUA), the Upper Confined Aquifer (UCA) and the Lower Confined Aquifer (LCA) with the Hope Minor Confined and Unconfined Aquifers (HMCUA) occurring as fans along the eastern margin of the Barnicoat Range.
The AGUA is up to 15m deep at the coast and has the highest recharge of the aquifers. It is fed from river recharge and rainfall infiltration. The UCA depth ranges from 18m deep near Wairoa Gorge to 32m deep near Bartlett Road where its upper confining layer is ruptured providing a hydraulic connection there with the AGUA. The LCA ranges from 30m near Wairoa Gorge to 50m deep extending an unknown distance beyond the end of Rabbit Island. Recharge to the UCA and LCA is slower, but is also from river infiltration and rainfall recharge.
Waimea Inlet is a shallow bar-built estuary open to Tasman Bay at the western (Māpua) and eastern (Nelson) ends of Rabbit Island. There are numerous islands within the estuary. The inlet has a large tidal volume which, combined with the shallow nature of the estuary and the large tides in Tasman Bay, results in a rapid tidal flushing. The major freshwater input is from the Waimea River, which flows almost equally into the SE and NW halves of the estuary. A further 22 small streams enter the estuary.
Tall forests dominated by beech and podocarp species originally dominated much of the FMU below the treeline outside the mineral belt. Valley floors were dominated by podocarp-broadleaved-beech forest of matai, lowland totara, black beech and silver beech, titoki and tarata, and in the south red beech. Kahikatea was very locally common where drainage was impaired.
The Waimea Plains were occupied by Māori from the 1500s, and became known as one of the most productive areas in Aotearoa. This included around 1,000 acres of cultivation called the Waimea gardens, located at the mouth of the Waimea River adjacent to a pā and kainga complex, with water sourced from the Waimea River. Smaller ’satellite’ pā were located elsewhere on the banks of the river and at the junction of the Wairoa and Wai-iti rivers.
Forest, fernland, and flax and raupō swampland covering the Plains was almost completely removed around the early 1840’s to make way for European farming and settlement. Early land use in the Waimea Plains following European settlement was predominantly pastoral farms, with limited irrigation usage.
Some lowland forest remains, but in much reduced area and much impoverished condition. Much of the original upland forest survives. Exotic forestry is located on the Richmond and Moutere Hills, with farming areas further up the valley towards Brightwater and Wakefield.
From the 1950s to today, land use has intensified largely through irrigation of horticultural land. Most of the Waimea Plains is currently used for intensive, irrigated horticulture and agriculture activities. Horticulture on the Waimea Plains is mostly apples, market gardening, viticulture and other intensive growing, and dairy farming (totalling approximately 1000 cows).
The largest settlement in the Waimea Plains is Richmond, with approximately 15,400 people, with smaller settlements at Brightwater, Wakefield, Māpua and Ruby Bay. Growth projections plan for mixed use intensification to occur in Richmond, and considerable further development to occur in Wakefield, Brightwater and Māpua.
The Waimea FMU lies mostly within the Moutere, Motueka and Bryant Ecological Districts. Much of the northern part of the FMU near the coast and on the plains is an acutely threatened environment, with under 10% of indigenous vegetation, and little biodiversity left. More intact ecosystems occur on the eastern hills with much of that area in indigenous forest.
Much of the original upland forest survives, but almost all of it is heavily browsed out by red deer and feral goat. Swamp forest now only survives as tiny pockets of a fraction of a hectare on several forested alluvial terraces. The most extensive areas in the FMU lies in the upper valleys of the Lee and Wairoa Rivers, on public conservation land. There are small areas of sedgeland with toetoe and ti kouka on cleared river terraces in the upper Lee, Wairoa and Wai-iti rivers, on what were formerly kahikatea-rich swamp forest/moist forests.
Remaining native forests provide habitat for what are now devastated bird populations with many former species extinct. Korimako/bellbird are by far the most numerous today, with hauhou/silvereye common and with tui and piwakawaka/fantail in moderate numbers.
There are 19 indigenous freshwater fish species in this FMU including koaro, upland bully, redfin bully, banded kokopu, longfin eel and shortfin eel. Streams draining coastal Moutere Gravel/Clay geology with reasonable habitat including riparian tree cover have reasonably high diversity. The rare fish, giant kokopu, is still found in some slow-flowing wetland-fed streams such as Pearl and Dominion Valley streams. Fish diversity in the upper part of catchments of the Richmond ranges is low, possibly due to the influence of the ultramafic geology. The non-migratory galaxiid Dwarf Galaxias is present in a few tributaries of the Wai-iti. In the Waimea River trout, common smelt, eel and common bully are the most common fish species, with a few Torrentfish hanging on in the riffles. The Wairoa, Lee and Roding have lower fish species diversity, maybe due in part to the influence of geology. Lamprey/kanakana/piharau are very rare in the FMU, but are found in the Lee River and parts of the Wai-iti. The pest fish, Mosquitofish (Gambusia) is present in slower-moving streams around the Waimea and Moutere Inlets.
The Waimea River has low macro-invertebrate scores, possibly due to elevated water temperatures. There are also concerns about the impact of vehicles on riffle-dwelling fish species such as Torrentfish, blue-gilled and red-fin bullies. These species are recognised as “in decline”.
Waimea Inlet is a shallow estuary with a great variety of habitats, partly because of the extent of the margins between islands and channels and varying freshwater and tidal inputs. Waimea Inlet was assessed as an “outstanding” “Site of Special Wildlife Interest”, particularly for water fowl and wading birds. The inlet is utilised by 112 species of marine invertebrates, 41 species of fish and 50 species of waterfowl. The inlet supports many threatened species, including Coastal Peppercress, and three species of birds, Australasian Bittern, Wrybill (Ngutu Pare) and the Black Fronted Tern (Tarapirohe).
Overall, despite extensive historical habitat modification, significantly reduced habitat diversity, and large areas of mud-dominated sediments, Waimea Inlet retains many areas of very significant ecological value. However, the prevalence of mud-dominated substrate, the persistence of localised dense macroalgal beds and high enrichment coniditons and pressures on salt marsh near the estuary margin from drainage and reclamation, are key broad scale habitat stressors that threaten these values. Salt marsh losses are likely to increase in future in response to sea level rise due to the current limited capacity for landward migration. Reductions in sediment loads, and targeted management of localised nutrient inputs, will be required to improve estuary condition.
The current state of water quality at the six river sites in the Waimea 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 Phosphorous, Water Clarity, E. coli and Macroinvertebrate 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.11 Trends over 5 and 15 years are also assigned based on five classes from very likely improving to very likely degrading.
The Lee and Wairoa Rivers, which are in the upper catchment and have good water quality in the A Band across all attributes. In 2015, Wairoa at Irvines had the highest MCI and SQMCI scores in the FMU.
The Waimea River generally has good water clarity and low levels of E coli measured at Appleby Bridge. However, in the lower reaches water clarity is one third less on average than at Irvines on the Wairoa. Nitrate levels and dissolved reactive phosphorus on the Waimea are also in the A band. However, daily maximum water temperatures regularly exceed 21.5 centigrade. There are also relatively few invertebrates and a limited number of the more sensitive kinds, resulting in lower than expected MCI scores (Band C).
Although Nitrate levels on the Wai-iti are within bottom line standards (Band B), they were found to be one of the fastest increasing rates for surface water observed for the Tasman Region. E.coli is also in the B band. Despite being in the A Band, dissolved reactive phosphorus and ammonia levels are also increasing over the last 5 years. Ammonia is most commonly associated with stock access to waterways (direct discharge of urine). Nitrates are mostly commonly associated with fertiliser or effluent.
Three sites are monitored for contact recreation on the Wairoa, Lee and Roding Rivers. These are all very popular swimming spots and show very low risk of infection. However, E.coli concentrations can sometimes be high after rain. In addition, the lower Wai-iti River (and to a lesser extent the Waimea River), which is used heavily for contact recreation, has one of the highest coverage of toxic algae (Microcoleus autumnale) in Tasman district. At least three dogs have died from eating this toxic algae, but there have not been any dog deaths since 2010.
Borck Creek is a partly spring fed creek where the surrounding land use is quickly becoming urbanised, with the waterway being modified as consequence of this. The creek has consistently high nutrient concentrations, low dissolved oxygen levels in summer and fine sediment deposits in the stream. Horticultural operations have been a significant contribution to nutrient concentrations, and the low dissolved oxygen concentrations are most likely from excessive aquatic plant growth. Macroinvertebrate communities are in the NPSFM attribute state D and is likely degrading, likely as a result of high nitrate concentrations (in the C Band and below national bottom lines) combined with fine sediment discharges from earthworks and subdivision. E.coli is also in the E Band and has been increasing at a high rate. Dissolved reactive phosphorus very likely improving and in the A Band.
Neimann Creek is a spring fed creek with similar issues to Borck Creek with high nutrient concentrations, low daily minimum dissolved oxygen and excessive fine sediment deposits in the stream bed. Nitrate concentrations have been improving in the last five years but remain in the C band, below national bottom lines. Patterns of nitrate with response to rainfall and season are very similar to that in groundwater about 1km upgradient near SH60. This shows that the source of nitrate is not close to Neimann Creek. E.coli is in the NPSFM attribute band E. Pukeko are likely to make a reasonable contribution to this.
Reservoir Creek has degrading E.coli concentrations in attribute band E likely from sewer leaks or wildfowl, and although Nitrate concentrations are within the B band, these levels show a high rate of increase in the past 5 years. The creek has poor macro-invertebrate habitat likely as a result of high peak flows and discharge of toxic contaminants such as chlorine and paint washings and high dissolved reactive phosphorus levels (in the C Band). The river is eroding and has been affected by land disturbance for residential development. Reservoir Creek is subject to contaminant discharges from private urban sections, as well as bigger flood flows and lower dry-weather flows because of the high percentage of impervious surface in the catchment.
With the long residence time in the groundwater system, it could still take up to 15 to 20 years before nitrate concentrations reduce to acceptable levels in these spring fed streams.
The predominant source of nitrate contamination in the Waimea catchment is a result of horticultural and agricultural land use, and associated management practices. A large proportion of the plains lies beyond the reticulated domestic wastewater system. Rural and semi-rural properties therefore have individual on-site wastewater systems discharging either primary or secondary treated effluent to land. While the contribution these systems make to the nitrate concentrations in groundwater is considered to be relatively small this relative scale does assume the systems are fit for purpose and appropriately maintained.
Elevated nitrate concentrations have been measured in parts of the Waimea Plains groundwaters since the 1970’s. An intensive piggery operation in the Aniseed Valley Road/Patons Road area is thought to be a major contributor to historic nitrate-N contamination, alongside diffuse nitrate-N inputs from horticultural and agricultural activities.
The plume of elevated nitrate concentrations has decreased over time due to its movement through the aquifer as well as the closure of the piggery in the 1980s. The highest nitrate concentrations in the Waimea Plains are currently where the UCA and AGUA merge together downstream of the piggery plume, around Blackbyre Road and State Highway 60. Some leakage from the UCA to the underlying LCA also occurs (between Ranzau Road and the Waimea Estuary) when the UCA passes over the LCA resulting in elevated nitrate concentrations observed in the LCA down gradient of this location. These elevated concentrations exceed the NZ Drinking Water Standard, and are affecting apple maturation when used for orchard irrigation. It is thought that local and upstream intensive land uses are causing the majority of these nitrate levels, particularly market gardening (vege growing).
Aside from nitrate-N, most other groundwater quality attributes in the Waimea Plains were well below the Aesthetic Values and Maximum Admissible Values from the New Zealand Drinking Water Notice and Standard respectively.
However, there were E.coli MAV exceedances for health significance in a number of bores/wells in the Waimea Plains. The majority of E.coli exceedances were found in shallow sites with contamination thought to be occurring due to inappropriate bore/well siting or poor bore/well head protection.
Waimea Inlet has a large proportion of the intertidal flats exposed for long parts of the tidal cycle. The estuary is relatively muddy, with 46.8% of the intertidal area consisting of sediment having >50% mud content, most of which is located in deposition zones in the mid-upper intertidal basins and embayments of both the east and west arms. The input of mud-dominated sediment appears to be largely historical, with anecdotal reports of high inputs sourced, in part, following the development of orchard land in the 1950’s and 1960’s. Seagrass beds are sparse across the estuary, covering ~2% of the intertidal area and located almost exclusively near the well-flushed entrance channel and central basin of the eastern arm. Nuisance opportunistic algal growths are uncommon, but a few localised hotspots (~20ha) still persist in 2020. Salt marsh remains a significant feature of the estuary (~10% of the intertidal) and is dominated by herbfield species. However, its prevalence is greatly reduced from its assumed historic extent through drainage, reclamation, margin development and channelisation. Since 1946 there has been a further reduction in salt marsh area of ~24%. Currently, initiatives are underway to enhance or restore some of this high-value habitat.
Estuary water at Māpua Leisure Park, Moturoa/Rabbit Island Boat Ramp and Best Island is generally swimmable for 90-95% of the time.
The Waimea Plains is one of New Zealand’s major horticulture areas and is highly reliant on irrigation. Irrigation accounts for around three quarters of all freshwater use in the Waimea FMU. The next highest user is public water supply, water storage, then smaller amounts taken for construction uses, timber mills, and other uses. Irrigation demand has increased as more land is used for more intensive agriculture and horticulture on the plains.
All takes are from groundwater with the exception of the Waimea East Irrigation Scheme (WEIS) which takes water directly from the Wairoa River. The WEIS scheme irrigates a wide variety of crop types on about 1000 ha of land along the eastern parts of the area between Richmond township and the Wairoa Gorge.
Properties in the urban areas of the Waimea Plains (e.g. Richmond, Brightwater, Wakefield, etc) are connected to a Tasman District Council reticulated water supply (groundwater piped from various well fields in the Waimea Plains) and connected to the Council reticulated wastewater network.
A well field in the Waimea Plains also supplies water to the coastal settlements of Māpua and Ruby Bay which are located outside of the Waimea Plains.
Away from the urban areas in the Waimea Plains, properties source water from their own private bores/wells and rainwater collection. They also rely on private wastewater disposal systems such as septic tanks, rather than any reticulated network.
The Waimea River has a mean annual low flow of approximately 1,200l/s at SH60 and completely dried up in 2001 during a drought. The Wai-iti catchment yields low water flows. These rivers all provide significant recharge to the underlying aquifer system in the Waimea Plains.
Freshwater resources in the Plains area are significantly over-allocated. Water users face significant seasonal restrictions due to natural fluctuations in river flow and low groundwater storage, that is, water in the Plains is unreliable. In addition the low flows are affecting the ecological health of the rivers.
The over-allocation is exacerbated during dry periods. River flows decline steadily in their lower reaches as drought proceeds and water usage continues. Groundwater abstractions, particularly in the summer season reduce river flows, and the two systems are directly linked. The Wai-iti River used to dry up frequently prior 2007, but since then the Wai-iti water augmentation dam has been operational. This has alleviated the low flows and the river drying effects and provided higher security of supply to irrigators and water users in this area. Pumping lowers river flows and coastal spring flows and also causes reduction in aquifer pressures along the coast which increases the risk of saltwater intrusion. Overall, during drought conditions, water availability is very limited on the Waimea Plains. This was experienced in the drought of 2000/01 when the river went dry and saltwater intrusion occurred.
The Waimea Community Dam is located in the Lee Valley and its 13 million cubic metre capacity is planned to provide water security to the region, including addressing over-allocation and unreliability of supply and allow some expansion of irrigated areas. During drier months, the dam will release stored water into the Lee River which will then increase flows in the lower reaches in the Wairoa and Waimea rivers and provide more water for recharging the aquifer. The reservoir may be ready for use in 2024.
Waimea Plains Groundwater Model Final April 2024 web.pdf (pdf 52 MB)
State of the Environment - River Water Quality in Tasman District 2015.pdf (pdf 33 MB)
Appendix 3 - Te Tau Ihu Statutory Acknowledgements 2014.pdf (pdf 216 KB)
Waimea Nitrates Science Review 2020_FINAL.pdf (pdf 3.5 MB)
Technical Report - Waimea Groundwater Quality Survey 2021.pdf (pdf 11 MB)
Waimea Estuary Saltmarsh Restoration Report_final 2021-04.pdf (pdf 5.3 MB)
Bryant Ecological District Report Sep 2020.pdf (pdf 4.8 MB)
Motueka Ecological District Report April 2014.pdf (pdf 2.7 MB)
Threatened Environment Classification
Waimea Inlet Broad-Scale Habitat Mapping 2020 Final_addendum.pdf (pdf 13 MB)
2023 Water Quality Trends in Rivers of Tasman technical report.pdf (pdf 2.3 MB)
FOR S&P COMMITTEE 2023 Waimea Groundwater Quality 2021 powerpoint.pdf (pdf 5 MB)
