Dear New Drainage Minister:
Much of the flooding problems in Barbados occur when storm water is not disposed of fast enough. Storm water can be disposed of in wells, in gullies, in agricultural land, or in communities. When it is disposed of in communities, we call it flooding.
Why are some communities experiencing flooding that never experienced flooding before? The most likely answer is that the former areas where water was disposed are no longer functioning in that capacity. The main storm water facilities that this applies to are the storm water wells.
The problem with storm water wells is that they require cleaning. However, another problem is that they are not always built properly. When excavating a storm water well, the well digger should dig until he finds a fracture or fissure in the rock. This creates the suck in a suckwell. The well digger should then dig a further 1.5 m (5 feet) to create a silt trap. The silt trap can hold enough silt for years, even decades, depending on the quality of the storm water. The additional cost to dig the well properly is between $0.00 and $300.
During the current building boom, inexperienced well diggers have dug wells that have had no fractures. Therefore, once they became full, they simply overflowed and flooded the area. Others have dug wells until they reached a fissure, and then they stopped without digging out the silt trap. Therefore, during rainfall, the silt quickly blocked the fissure, and the well would overflow when it became full.
Why are the older wells, which have been recently cleaned, also clogging up quickly? The principal reason for this is that agricultural workers remove the vegetation from the side of the road. This vegetation helps to prevent the silt from washing into the road and blocking the wells. Once the wells, that intercept water flowing towards a community, are clogged and overflowing, then the community will receive a larger volume of water from even a short rainfall event.
This is how they still do it in some rural communities. The Khus Khus grass binds the soil and prevents the washout of silt.
Observe this fellow as he removes the protective grass from the soil on the ridge.
This loose soil will soon wash onto the road and clog up a newly cleaned well during the next rainfall event.
Observe this fellow killing the protective grass bounding the road.
With the removal of the grass, the storm water will wash the silt onto the road, and down the well where it will clog the fissure.
This reveals another problem. If we build our roads below the level of the adjacent agricultural lands, then the storm water will flow from these lands onto the road. Therefore, you should coordinate your work with the Ministry of Agriculture and the Ministry of Public Works.
Perhaps you could consider the following. Your Ministry could:
1. instruct all well diggers on the proper method of constructing a well.
2. clean out the silt from the existing wells, and install silt traps within them.
3. instruct the Ministry of Agricultural to stop agricultural workers from killing the protective grasses on the roads that bound agricultural lands.
4. instruct the Ministry of Public Works not to build any more roads below the level of the adjacent agricultural road, unless it is consciously done with sufficient facilities to detain the silt.
Finally, do you know the principal reason why Barbados is experiencing so many flooding problems in 2008? Perhaps this can help. In the 1970’s there were several Chartered Engineers working in the Ministry of Public Works. Today, there is not a single Chartered Engineer in the entire Civil Service of Barbados. It is a lack of knowledge problem.