The Samaan Grove Wetland System

Description of the Project

by Kevin Kenny

Click images to enlarge
   
Over the years, residential communities that developed in the areas of Mount Pleasant, Buccoo, Golden Grove, Canaan and Bon Accord did so with little care or understanding of the effect that surface water runoff had on the marine environment. In the areas surrounding the new development, residential communities were built on a solid coral substrate where individual septic tanks were constructed without the assistance of mechanical equipment. This resulted in tanks that were undersized and often very shallow. These tanks functioned reasonably well during the dry season. However, in the rainy season when there was a substantial increase in the water flow and when the water table was at its highest, they were too small to handle the extra volume. As a result, the excess overflowed into nearby drains, eventually making its way into the marine environment and on to the reef, where it fertilized marine algae which smothered the coral.


Drains overflowing after a
heavy rainfall


A drain being dug in coral with a mechanical hammer 
 

The sea was further overloaded with the construction of two low-income housing communities which utilized package sewer plants that always seemed to malfunction. Sewage was efficiently captured but allowed to flow down the drains into the sea every time the waste treatment plants did not function as designed. Both of these developments were located adjacent to Buccoo Reef. This reef, now a national marine reserve, is polluted and stressed to the point that it may no longer be the main tourist attraction of the island.  

In the first stage of the development of the resort community of Golden Grove, the company decided to incorporate some innovative techniques to show how well they would work. Angostura Resorts, the developer, sought low-tech solutions to deal with surface water runoff. In the first phase called Samaan Grove (a 12 hectare [30 acre] residential development), we decided to construct 2.6 hectares (6.4 acres) of fresh water wetlands, ponds and lakes, part of a proposed overall plan to develop 32 hectares (80 acres) of man-made wetlands that would trap sediment.  

We would use bog plants to remove the contaminants and nutrients that flowed down the various drains through the estate on the way to the sea. Silt and garbage traps were developed and installed at the entrance of the development. Deep and shallow lakes were constructed that would slow the speed of the sediment-laden run off and catch some of the heaver particles. An inventory of the local bog plants was compiled, later collected and planted in the new man-made wetlands. Where possible local bog plants were used, though we felt that we needed to have many varieties of plants to improve the effectiveness of the natural filter.

One of the key requirements of the project was to use these water features to visually improve the vista for residents so that they would become connected to the wetlands and the wildlife they attract.

Flowering bog plants were chosen wherever possible to give the impression of a garden, in the hope that residents would think of these green spaces as recreational and not wastelands. We hoped that these landscaping improvements would lift land values to offset for the very high initial cost of developing the wetland system. This would be the ultimate test of the term "sustainable development" where the cost was fully recovered by the additional premium charged to live in this unique community.
Setting the tone for Samaan Grove, were Ed Stone & Associates (EDSA), our landscape architects, in particular Bob Dugan. They developed a magnificent entrance which includes a large copper vessel that holds our signature waterlily, the Nariva red night bloomer. They provided the layout of the wetlands, ponds, lakes, roads and bridges which make the community a very attractive place to live. The beautiful bridges and winding roads combine to make every feature of design a thing of wonder. The same was done for the utility buildings, with the guard hut, sewer lift stations and well combining both form and function, showcasing the design work of John Otway, our design consultant.   

Together with John Otway Design, we conceived four model homes, built and landscaped to set the standard for design, construction and landscaping. Two features of these houses were the use of recycled PET plastic bottles as a roofing material and the elimination of hard surface driveways. The company also developed covenants as part of the lease which defines how owners operate within the development.   


Samanea saman 

Great care was taken to preserve the existing trees on the development. All the samaan trees (Samanea saman) that were in the path of the road were carefully removed and placed in a holding area. Most of them have since been replanted in the development.

The engineering and project management was provided by Alpha Engineering and in particular Fazir Khan, who spent many hours researching the internet and reading countless journals and papers on man-made wetland construction. Alpha also provided the engineering expertise to develop the sewage solution. 

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