Geography and Terrain
Trinidad & Tobago are the southern-most islands in the Caribbean, located next to Venezuela. The landscape of Trinidad is varied and begins in the north with a large mountain range, which is an extension of the same geological formation seen immediately to the east on the Paria Peninsula of Venezuela, where Trinidad, in fact, represents the very end of the Andes Mountain Range above sea level. The Trinidad northern range comprises very steep hills and mountains and deep valleys, and for the most part, a reddish brown residual soil layer underlain by layered shale rock. The soil types across Trinidad are extremely varied as can be observed on its very diverse and colorful soil map, and in the central and southern parts of Trinidad another very notable soil formation is present in the lower lying areas known as the ‘sapote’ or ‘heaving clays’. The low lying and gently grading nature of the terrains in these areas is a direct tell-tale to the inherent instability of these soils since over millennia it has found equilibrium in a position which is very near to flat.
Tobago is hilly and mountainous in some areas and dominated by the Main Ridge whose formation runs most of the island’s length from southwest to northeast. There are deep, fertile valleys running north and south of the Main Ridge, and the southwestern tip of the island comprises of an undulating plain and a coral platform. The island is volcanic in origin although there are no active volcanoes – but this has lent to the fertility of the soils and contributed to the general soil’s makeup – which is a combination of residual (degraded from parent rock) and alluvial soils. The mountain’s conditions in the northern part of the island have resulted in most notable cases of erosion and land slippage being concentrated there, although greater development in the south has also contributed to these effects there.
From the challenging soils of the central and south Trinidad to the steep hills in the north and various parts of Tobago, the development and construction of civil works and buildings has seen various challenges, which has required a wide range of engineering solutions and has seen an evolution in approaches, expertise and innovation. Agriculture in the diverse range of terrains has also seen farmers developing their expertise and understanding, and specializing in land management practices to best suit their local conditions.
Vetiver Grass in T&T
Based on anecdotal evidence it appears that vetiver grass has been present in T&T for more than 50 years, though how much longer is unclear. Though in small amounts, existing plantings installed decades ago can be found in various towns of northern Tobago on steep roadside slopes, and one such installation was found in Paramin on a driveway embankment before the original Vetiver Education & Empowerment Project (VEEP) was conceptualized and implemented there, in 2016. The owners of this property indicated it has been there since the time of previous owners, at least 40-50 years ago. In addition older members of the community shared memories of a time when vetiver was quite prevalent and well known for slope stabilization in Paramin; where however that knowledge was lost as younger generations grew up, and most cases of vetiver were eliminated using strong herbicides due to lack of value for its bioengineering functions. There are also multiple long-existing cases of vetiver plantings on the Uriah Butler north-south highway in Trinidad for the stabilization of roadside embankments in the sapote clays – where it is understood these were installed during the period of construction in the 1950’s. Even while being burned by annual bush-fires these plantings continue to serve their purpose today.
One point to note however is that implementation of vetiver grass in hedgerow formation to prevent erosion and for soil and water conservation has not been observed, where plants installed in earlier times have been generally done so haphazardly or ‘diamond’ formations. While some benefit is still provided by these plants, other benefits are lost and erosion in between plants is great in some cases, allowing gullying and sedimentation downstream. Since strong reintroduction and educational efforts began during the last 5-10 years, by local advocates such as Vetiver TT Ecological Engineering Solutions Ltd, Wa Samaki Ecosystems, and others, there has been a growing appreciation and interest for vetiver grass capabilities to tackle land and water related challenges. Government bodies such as the Ministry of Works and Transport have also recognized the value of correct implementation of the Vetiver System (VS) in hedgerow formation, and have in some cases begun including instructions to support this in their design specifications for infrastructure projects. IAMovement and Vetiver TT EES Ltd are currently spearheading various projects for ongoing awareness raising and knowledge transfer of vetiver grass uses and capabilities, such as via VEEP model scaling to other communities and areas, including Quarry Rehabilitation, and a new technical assistance project just beginning with the Inter-American Development Bank (IDB) called ‘Building on Vetiver!’.