[MQP] Improving Drinking Water Quality on Barro Colorado Island, Panama

Executive Summary

This project investigated water quality issues on Barro Colorado Island (BCI), located in Lake Gatun (part of the Panama Canal). The Smithsonian Tropical Research Institute (STRI), a research foundation on BCI, has reported problems with drinking water quality on BCI as a result of the Panama Canal Expansion Project dredging activities. In particular, the drinking water source at the intake in Lake Gatun has elevated levels of turbidity. STRI has been investing more than $20,000 annually to import potable water for drinking purposes. The objective of this project was to examine the current drinking water quality on BCI and assess the water supply needs of STRI in order to provide a feasible solution for their water quality problem.

Construction of the Panama Canal was started in 1881 by France, but was eventually abandoned due to design problems, lack of funding, and diseases affecting workers. The partially completed canal was eventually sold by France to the United States, who took over construction in 1904 and finished the project in 1913. The United States owned and operated the canal until 1999, when it was officially turned over to the Panamanian Government.

The Panama Canal is 83.7 kilometers (52 miles) long and is the shortest route to travel from the Pacific Ocean to the Atlantic. The canal is Panama’s largest economic resource because it has become a center for world trade, transportation, and logistics. The canal consists of two channels on either side of Lake Gatun. Locks lead into each channel and control their water levels, raising ships up to Lake Gatun’s height and then back down to sea level.

The Panama Canal is currently undergoing an extensive expansion project which began in 2007 and is expected to be completed by 2014. The expansion project is estimated to cost $5.25 billion. The goals of the expansion project are to: 1) achieve long-term economic sustainability and growth, 2) maintain competitiveness, 3) increase capacity, and 4) enhance the productivity, safety, and efficiency of the canal.

As part of the canal construction, the Chagres River was damned in 1914, which flooded the Chagres River Valley, and created Lake Gatun. BCI was formerly a hill in the valley, and then became an island after the valley was flooded. After the canal began operating, BCI became a permanent biological reserve. STRI was established in 1923 to provide research opportunities for long-term ecological studies of a variety of flora and fauna on BCI.

STRI draws water from Lake Gatun for their potable water needs. Periodically, the turbidity level of the raw water has been elevated, presumably due to the dredging in the canal. High turbidity in drinking water is a potential problem because particles may harbor microbiological contaminants that are harmful to human health or that decrease disinfection effectiveness. In Panama, turbidity measurements are used by drinking water utilities for process control and regulatory compliance and the maximum turbidity level for drinking water is 1.0 NTU. At BCI, the high turbidity caused failure of the drinking water treatment system, and forced STRI to import water from the mainland in five gallon jugs for drinking purposes.

Three alternative solutions for STRI’s turbidity problem were proposed to the group by the Panama Canal Authority (ACP, Spanish acronym). The first alternative involved moving the water intake to a location where the source water would be least adversely affected by the dredging activities of the Canal Expansion Project. The second alternative entailed adding a system of sedimentation ponds before the filtration units in the water treatment system. Both alternatives would result in a lower turbidity in the influent. Also, they would both utilize the current water treatment system and no further improvements to reduce turbidity were expected to be necessary. The third alternative was to continue the transport of water from Gamboa to BCI, utilizing an improved transport system.

Specific Data were collected to evaluate the proposed alternative solutions to STRI’s turbidity problem through reports from ACP and STRI, interviews and conversations, and field data collection. The reports contained information about: water quality testing data for Lake Gatun, water quality regulations, current BCI water quality issues, and the potable water transport system. The group held interviews and conversations with various members of ACP and STRI, as well as an engineer from E. T. Engineering Enterprises, Inc. Lastly, the group collected data in the field through water quality testing and a pipeline route investigation.

STRI’s water treatment system consisted of a water intake near STRI’s docks. From here, the water was pumped to a prefilter for removal of particulate matter, and then to a concrete storage tank. Next, the water flowed through filters and then was chlorinated and pumped into a metal storage tank, where it was stored before being distributed to STRI’s facilities. Currently, STRI’s filtration units are not operational because of the increased turbidity, so the water is only being chlorinated. This practice does not produce potable water for STRI. Therefore STRI has been spending $21,000 annually to import drinking water from Gamboa on the mainland.

Water quality testing in the Panama Canal channel in Lake Gatun showed high turbidity levels (up to 100 NTU) from August 2003 to December 2005, from January to December 2007, and in late 2009. The group conducted its own water quality testing at STRI’s current water intake location and three proposed intake locations. These alternative locations had turbidity levels of approximately 1 to 2 NTU, significantly lower than those for the current intake location and the channel in Lake Gatun (20 NTU). Possible pipeline routes that would connect the proposed intake locations to the current water treatment facilities were evaluated through field reconnaissance. The shortest route started at Wheeler Cove, in the south east region of the island, and traveled through the island to the treatment facilities.

quantity, cost of implementation, and environmental impact on the island. Moving the water intake would greatly improve the raw water quality. The cost of new piping and other construction materials would be approximately $67,000, and this alternative would have a significant negative environmental impact on the island from land clearing and construction. While installing sedimentation ponds would likely improve the raw water quality, the group was not able to acquire basic design data for this alternative. Transporting water from Gamboa would provide STRI with their minimum potable water needs (drinking water only) and, would not have any negative environmental impacts on BCI. However, water needs, including showering and laundry, would not be met with this alternative. ACP has supplied materials valued at $15,600 to import water in 200 gallon containers. The cost to construct this system is currently being estimated. While importing water currently costs STRI approximately $21,000 per year, the improved transport system is expected to have a significantly lower annual cost.

The group initially recommended moving the water intake to Wheeler Cove so that STRI would have access to a sustainable, better quality raw water supply in Lake Gatun that would meet all of STRI’s water quality needs. It was anticipated that STRI’s current treatment system on BCI would be able to treat the lower turbidity water. However, due to future dredging activities (expected to be completed by 2014), Wheeler Cove could be subject to increases in turbidity and these levels were unknown.

The group was informed in February 2010 that STRI had rejected the option of moving the water intake due to the significant adverse environmental impacts associated with construction of the pipeline on BCI. As a result, the group recommended that STRI implement the improved water transport system designed by ACP.