During Tropical Storm Erika, many areas of Dominica experienced more than thirty-three inches of rainfall, with soils already saturated from storms occurring the week prior. The resulting landslides and floods caused significant damage to the infrastructure and left many communities, including Soufrière, cut off from the rest of the island. In a meeting with residents of Soufrière, Galion, and Scott’s Head, the number one concern voiced was clean drinking water and sanitation. The proximity of a runoff stream to the source led to flood water breaching the uncapped cistern and contaminating the drinking water for more than ten thousand people. The mission of the Water Analysis and Sanitation team is to assess the water quality and sanitation needs in communities across Dominica to improve public health while maintaining the marine and natural environment.
To assess drinking water quality from the source cistern, the group performed water tests throughout the Soufrière water system and along the adjacent stream. Tests included pH, Conductivity, Total Dissolved Solids (TDS), Salinity, and Total Fecal Coliforms. The pH levels throughout the water system were found to be acidic, which can cause corrosion to piping and produce a generally sour taste. Tests also indicated the water was highly conductive, with high numbers of ionized particles, turbid within reasonable drinking limits, and high levels of salinity causing a salty taste. Total Fecal Coliform testing was done to sample the number of microbial pollutants in both the cistern and adjacent stream.
Chlorine is added to the cistern near outtake locations where the water was sterile as chlorine levels were high. However, upon testing the natural wall of the cistern, higher coliform numbers were found, indicating poor mixing of the chlorine. Tests done along the runoff stream and alongside the low concrete wall of the cistern found too many fecal coliforms for our equipment to count. During any storm in which the runoff stream water breaches the low concrete walls of the open cistern, the drinking water going into the communities could become extremely hazardous and pipes would likely need to be flushed out and sterilized after every occurrence. To combat these issues, the team is proposing a variety of potential solutions for discussion with the affected communities. The first priority for the Soufrière water system is to improve the cistern at the source by building a concrete wall where one of the sides is currently a dirt embankment, creating safety barriers to prevent any mixing with the adjacent stream, and capping the system to prevent potential overflow contamination. The team used state-of-the-art LiDAR scanning technology to survey the entire water system area during the Spring Break trip and is currently working with community members to design these solutions. The second priority will be cleaning up the Alumn Stream before it flows into the sea through better community waste management and potentially water treatment. The team is assessing the viability of biodigester systems in the community which would treat human waste, remove microbial pathogens, produce a contained source of methane gas, and eliminate the use of soak pits and flow of waste into the environment.