Chagres River Valley, Panama (IMAGE) Smithsonian Tropical Research Institute Caption The Chagres River is the major tributary to the Panama Canal. Landowners in the watershed may make more environmentally friendly land use decisions when Payment for Ecosystem Services programs are in place. Credit STRI archives Usage Restrictions Credit: STRI archives License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.