Dam activity changes the color of Macal River
The Macal River as it sits behind the Chalillo dam has its natural coloration. But the water that the dam is pumping out from lower level outlets is yellow oxide; the color of the clay sediments churned up from the river bottom. BECOL has blamed deforestation and xateros for the soil deposits in the river during heavy rains and floods. The Belize Institute of Environmental Law and Policy (BELIPO) believes there is a health risk at hand. So they took some pictures upstream and sent them to its international network of scientists for review. News Five spoke to Dr. Guy Lanza, microbiologist and Director of the Environmental Science Program at the University of Massachusetts via phone today regarding his findings.
Dr. Guy Lanza, Professor of Microbiology, UMass
“A very large quantity of bottom sediments were released from the dam and completely caused the turbidity shock – suspended materials clays and other material in the river which causes an immediate water quality problem.”
Jose Sanchez
“And what does that mean for the people who live on the riverside? Can they ever use that water?”
Dr. Guy Lanza
“It will take some time for the materials to settle out and for the water to clear before they can use it. It’s very, very difficult, in some cases, impossible to treat the water with high turbidity levels for drinking purposes, either for humans or livestock and in addition to that there are problems with the natural organisms living in the rivers downstream from the dam; fish, fish food, organisms, the whole series of the food web that lives in the river will be damaged from the turbidity shock”
Jose Sanchez
“For people who may actually use it as drinking water, is it possible to filter and disinfect this water?”
Dr. Guy Lanza
“Its use, you can have extreme hardships in filtering the water with the turbidity I saw in those photos because the amount of material is so high, especially the clay materials, because it will clog the filters that are used to pre-treat the waters before you disinfect.”
Jose Sanchez
“In your thirty-five years of experience, have you ever seen anything of this sort that caused illness to humans?”
Dr. Guy Lanza
“There is one example that’s on record. In 1993 there was a turbidity increase in the drinking water supply outside of Milwaukee, Wisconsin, USA. Four hundred thousand people were affected with waterborne diseases because the turbidity blocked the treatment of the water. And of those four hundred thousand, more than one hundred people died. That was because of the disease causing organisms were protected by the high turbidity in the water. And, therefore, it couldn’t be effectively treated.”
Jose Sanchez
“Is there a solution that we can look at right now?”
Dr. Guy Lanza
“That would be very, very site specific and at this point the first thing that would have to be done would be the immediate halting of releasing those sediments. But it’s going to take time, especially the clays. The clays have very fine particles and they form colloidal suspensions and they don’t settle out quickly. Instead they will continue to be there to interfere with disinfectant processes and light penetration that’s essential for a healthy river.”
Dr. Lanza says because his analysis is based on photos, it is difficult to predict the amount of time it would take the Macal River to recover. However, he does not recommend farm animals to drink from the river.
