The Vetiver Network International

SMALL ISLAND DEVELOPING STATES (SIDS) – Important possibilities for the Vetiver System

Some of the oldest Vetiver System applications are on the Pacific Islands (Fiji) and the Caribbean (St Vincent and the Grenadines). These island states in development jargon are known as SIDS. Most of the SIDS are very small and are faced with huge problems in the light of population expansion and climate change.  Development funds are very limited and thus there is a need to introduce low cost technologies that fit the needs of the islanders. The Vetiver System and its many applications is a perfect technology to support community infrastructure and agriculture in many SIDS.  To illustrate this potential, I asked Andy Kirkwood to write about his experience in the Cook Islands, describing the need, how VS could be applied, and what communities are currently doing with the technology. Andy is an environmental consultant  –  Avana Vetiver – with a vetiver plant nursery and Vetiver System consultancy. The background scene and his views set out below could, I believe, be of value to others who live and work in SIDS

Cook Islands Country Profile
The Cook Islands are distributed over 2.35 million square kilometers and comprises 15 islands with a combined land mass of just 240 square kilometers. Locally, the islands are grouped by those which are less accessible and lie north of the equator (the Northern Group); and the Southern Group which includes Rarotonga: the capital island and only international airport.

Geologically the islands include volcanic seamounts (Rarotonga, Mangaia), sand atolls (e.g. Aitutaki, Palmerston, Suwarrow), and makatea (fosilised coral). Not all islands are inhabited, with Takutea, Suwarrow, and Manuae either designated bird sanctuaries or culturally managed protected areas. The climate ranges from tropical to sub-tropical, with cyclones a key climatic hazard Nov-Apr each year

Economy and Development
Tourism is the main economic driver – a recent (2022) estimate is that this sector accounts for 77% of GDP. Pre-Covid visitors numbers reached a peak of 170,000, with a permanent population of only 17,000. There is increasing pressure on land-use and water resources. Infrastructure has struggled to keep pace with tourism growth.

  • Environmental management has direct bearing on the viability of commercial tourism. The changes to Muri lagoon – the Cook Islands signature tourism destination – are a recent example. Nuisance seaweed growth led to the cancellation of stays and the relocation of visitors to accommodation in other districts.
  • The minimum wage was increased in June 2022 to NZD$8.50 / US$5.40 / per hour.
  • Development is typically located on the outer flatter perimeter (coastal dune area) of each island.
  • To stabilise dune areas, coastal sands are mined (for use in construction) and excavations in-filled with clay soil. This results in surface flooding which then undermines the main ring road, and increases sediment-nutrient transport to the lagoon.
  • Inland wetland areas (previously natural retention ponds) have been in-filled for housing.
  • Coastal development has displaced agriculture inland to steeper, more difficult to cultivate terrain.
  • In Rarotonga livestock are typically tethered or penned along waterways: shaded areas less suited for growing crops or infrastructure.
  • Intensive storm events result in ephemeral streams and surface flows that wash agricultural inputs, soils and livestock effluent toward fringing or internal lagoons. A storm event in May 2022 recorded nearly 70mm of rainfall in 24 hours.
  • Exotic timber plantations have previously been planted on some islands (1984-1994), and are not actively managed. In Mangaia, the 900ha Pinus caribaea plantation has negatively impacted groundwater recharge: resulting in a reduction of river flows by up to 80% in the dry season. This affects the irrigation of taro beds – the staple food crop.
  • On all islands, septic wastewater disposal is on-site: there is no reticulation although solids are removed to a central landfill treatment pond. Resort wastewater disposal fields along the Rarotonga coastline are located in free-draining coral sand. Algal blooms in Muri lagoon (Rarotonga) have been attributed to nutrient-rich ground- and surface water flows. An extended dry period and settled weather in January 2021 exposed organic rich shoreline sediment, the resulting biological oxygen demand resulted in lagoon die-off.
  • Coastal water enrichment due to anthropogenic impact is linked to the taramea (crown-of-thorns starfish) outbreaks, with the larvae spawning origin point identified as the intensively urbanised commerical district of Avatiu-Avarua. The fringing reef protects low-lying developed areas to the full force of tropical cyclones. Wave heights of 14m have been along this stretch of coastline, which housing government administration buildings, land records, fuel depots, and the international airport.



  • As a sector, agriculture receives only modest support from government. The agricultural projects budget allocation for 2022/23 is NZD$300k / USD$190k.
  • Around 65% of food – including fresh produce, eggs, and meat – is imported, as is all livestock feed.
  • The 2021/22 Agricultural survey indicates around a quarter of all households grow domestically.
  • Culturally, crop and plant exchange is common. There are only a few private nurseries, and these usually supply grafted fruit trees or exotic ornamentals, e.g. flowering shrubs, bromeliads, palms.
  • The priorities for agricultural smallholders are subsistence and short-term cash crops; taro, kumera, and maniota/cassava), fruit, flowers. Tree crops are rarely cultivated at scale, aside from paw paw and banana. A few small citrus plantations remain from those originally planted in the 1960s.
  • The less-populated islands have more favourable climates for certain (cooler-climate) crops, but have diminishing labour force due to outward migration. Northern Group islands tend to have only sandy, low-nutrient soils less suitable for agricultural production. Rarotonga’s tropical climate and rich volcanic soil is ideal for vetiver growth.
  • Comments from a 2022 (Fiji) Foundation for Rural Integrated Enterprises and Development talanoa (dialogue) were telling. Especially when land has been leased, a marketable food crop was preferred over planting companion and beneficial plants such a vetiver or mucuna (a beneficial legume).

Cook Islands Vetiver System  (VS) application areas
Key VS application areas for the Cook Islands:

  • Stormwater management: slowing and directing surface water, increasing drainage/infiltration (e.g. rain gardens). Domestic drainage design is ad hoc (no reticulation), with occupiers often directing flow to uncleared areas or nearby waterways which discharge into wetlands or the lagoon.
  • Wastewater: improving/intensifying (septic) wastewater disposal field design, at the domestic and commercial-tourism scale.
  • Infrastructure protection: reinforcing road sidings, dust containment (unsealed roads and accesses), cut slope and developed streambank stabilisation.
  • Coastal protection: against storm surges and to mitigate the impact of inland flooding.
  • Ecosystem restoration: as a pioneer plant for the re-wilding of developed riparian areas.
  • Dumpsite leachate containment (landfill is currently the only form of waste management).
  • Agricultural extension: rain-fed farming (soil and water conservation); organic production, livestock effluent containment and treatment.
  • Agricultural-use of vetiver cropping methods would be highly-beneficial, toward the end-goal of sustainable land-use, and transition to rain-fed and organic-regenerative practices. Government has signaled the intent to introduce water tariffs 22/23 which will impact on the commercial viability of growing in flat coastal (sandy-soil) areas. Organic methods will also improve food security by reducing agricultural input import dependence.

Raising awareness of the Vetiver System (VS) in the Cook Islands
The Cook Islands has previously benefitted from the pioneering work of consultant Don Miller, who was part of a New Zealand government ODA program in the early 1990s: promoting VS for erosion control and infrastructure protection (road stabilisation) in the islands of Mangaia and Atiu.

  • In 2012, Ministry of Agriculture planted a cut slope residential demonstration site in Rarotonga as part of environmental awareness ‘Lagoon day’ activities.
  • Regulatory agency, National Environment Service include information about vetiver (the plant) in public outreach activities.
  • Since 2019, TVNI member Andy Kirkwood has been advocating for VS applications in infrastructure, agriculture, and climate crisis mitigation. In parallel, he has established an independent nursery (Avana Vetiver) to provide VS specification and slip supply.

Community Group Vetiver System Advocacy and Implementation

Te Vai Ora Maori (TVOM)
TVOM has been advocating for culturally and environmentally-appropriate infrastructure. Since 2019, the community group have been promoting VS to supplement traditional hard engineering approaches.

Fig 1 – disposal field design schematic

The group were successful in vetiver being specified as a preferred crop for the proposed Muri septic reticulation (Mei Te Vai Ki Te Vai – MTVKTV). The grass will allow for steeper land to be considered for wastewater disposal: stabilising slopes and processing nutrient and water. Government engineers visited the Avana Vetiver demonstration site to see a working example of vetiver hedgerows, and commissioned Dr Paul Truong (Australia) to model effluent uptake of potential sites.

Concept note: Land-based Disposal of Wastewater using Vetiver for Muri Septic, Rarotonga, Cook Islands.
MFEM confirms preferred option for future wastewater treatment

Fig 2 – Concept notes: Rarotonga: Alternatives to Chemical Water Treatment.

– Vaka (island-regional) presentation of physical water treatment methods in association with the Kotou Nui (traditional leader association); and to the Are Pa Metua.

– Presented to the new Water Authority (Bill) select committee, on vetiver benefits to public utility operation: by increasing groundwater to sustain streamflow over periods of low rainfall; and reducing sediment loads (and associated chemical sedimentation costs) by stabilising valley catchment areas. [Image in file: presentation slide]

– Proposed vetiver constructed wetlands for the ten newly constructed drinking water treatment facilities. This was in response to the Water Authority’s application to dispose of water treatment by-product (chemically-treated water) to freshwater streams; and to mitigate the risk of stockpiling of chemical sludge at elevated, sloping treatment sites.
Concept note: Vetiver Cyclic Wetland: Te Mato Vai Betterways.

– Successfully lobbied government to have the Cook Islands included in new Kiwa initiative (UNDP nature-based solutions initiative).

2022: Acting chair Justine Flanagan presented the VS – as ‘domestic infrastructure’ – to the influential Cook Islands Business and Professionals Women’s Association. The audience included large contingent from the government Ministry of Finance Development (ODA) Co-ordination Division; and the Climate Change Office.


Fig 4 – Vetiver is recommended as it can prevent contamination from drift and also intercept groundwater flow

Natura Kuki Airani – Cook Islands Organics Movement
Natura Kuki Airani is the Cook Islands organics movement (producers and consumers); and are licensed to certify product under a participatory guarantee system to the Pacific Organic and Ethical Trade Community ― ‘Organic Pasifika’ standard.

Since 2019, NKA has been promoting vetiver to growers and domestic gardeners as a cropping system, for rain-fed farming, slope stabilisation, as a buffer crop * Under the Organic Pasifika standard, a 4m buffer zone is required around an organic field to qualify for organic certification), mulch production, and for soil and water conservation.

Fig 5 – World Food Day “signage”

Community engagement has included organic garden open evenings (where vetiver is used as part of a cropping system), the sale of slips and potted nursery plants, slip preparation demonstration, and the distribution of planting information sheets at the annual World Food Day events (2019-2021).


Avana Vetiver – VS Consultancy/Nursery
Avana Vetiver has established a hillside vetiver nursery and VS demonstration site, with examples of slope stabilisation, and modelling organic cropping methods. A cut slope application is planned for 2022.

Fig 5 _ Avana’s hill side vetiver nursery

As a certified organic producer: vetiver slips can be directly planted into other certified organic fields.

Avana Vetiver has been supplying the vetiver slips used by community groups Muri Environment Care, and environmental NGO Te Ipukarea Society (TIS) for riparian planting and coastal protection projects.

In 2021 provided consultancy services to government: assessment of stream sediment inputs to specify vetiver interventions.


Fig 6 – Community planting of vetiver to protect stream banks

Muri Environment Care

  • With the support of the Ministry of Marine Resources, Muri Environment Care (MEC) have undertaken the restoration of riparian ecosystems through the tourism centre of Muri village (Rarotonga). The streams in this area have been identified as a key source of nutrient and sediment impacting the health of the Muri lagoon.
  • MEC have established a native plant nursery for propagation and to model planting plans. Vetiver is used for mulch and slips will be grown for future stream planting projects.
  • Community engagement has included liaising access with landowners of stream areas ― all land is privately/traditionally owned in the Cook Islands.
  • During Covid border closures, local businesses provided staff to assist with the clearing of invasive species, and replanting with vetiver to stabilise stream (sand) banks. This was an opportunity to increase business/tour operator knowledge of local biodiversity and stream management activities.
  • Youth are involved through trainee teacher and school programs. Documenting holiday program activities has led to a dedicated Youth (teen) Media Team, who are mentored by a media professional on television and press production.
  • See:

Te Ipukarea Society

  • In 2020, local environmental NGO, Te Ipukarea Society undertook a project to address foreshore erosion at Avana Harbour in Rarotonga, Cook Islands. The pilot project integrates a nature-based solution to address the problem of sea level rise and shoreline retreat. This harbour area is used by artisanal and small-scale commercial fishermen and is also a popular community swimming area. The seawall enables access to boat moorings.

    Fig 7 – Harbour wall stabilized with geotextile sandbags with vetiver protection.
  • A 45 metre engineered stepped seawall of sand-filled geo-textile bags has been reinforced with coastal planting including a vetiver hedgerow, beach vines, and native trees. The plantings provides a second level of natural defence against over-topping of the geo-textile structure. Vetiver was selected for the strong, deep root mass and resilience to coastal environment as well as being non-invasive.
  • If damaged by storm events, the geotextile bags can be easily removed, and leave behind only sand, rather than scattered rock or concrete.
  • Planning for a second phase is underway and will extend the geo-bag wall with additional vetiver planting.


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