• www.sierralacandon.org/po-hydrology.html

The Usumacinta River Basin covers an expansive area that includes much of Guatemala and Southern Mexico. For several decades now, various plans have been put forward to harness the river's energies through a series of dams placed along its middle route, where it forms the border between the Mexican state of Chiapas and the Guatemalan department of the Peten. These plans appeared to have been shelved by the Mexican government in 1991 (Wilkerson 2001). However, recent reports from periodicals suggest that the plan has been revived, and that dam construction may go forward. Although most observers recognize the potential economic value of producing hydroelectric power on the Usumacinta, the cost to the cultural patrimony of Guatemala and Mexico is unknown.

We know that we would lose much of Piedras Negras and Altar de Sacraficios in Guatemala, as well as large portions of Yaxchilan in Mexico to the rising river behind the dams. This in and of itself would be a catastrophic loss to the patrimony of these two countries. But in truth, no scientific survey of archaeological sites has been undertaken along much of the river's course, and the low, swampy areas that form large portions of the Sierra del Lacandon National Park in Guatemala are among the regions in most serious threat should the waters rise. Should dam construction take place before a thorough archaeological survey can be completed, we will never know what was lost.

Based on the available data regarding dam construction location and projected levels of flooding, the large urban center of Piedras Negras would become a set of islands and peninsulas jutting out into the river. Those areas that remained above water are the most thoroughly studied, and those areas that would be inundated still require investigation.

The site of Yaxchilan in Mexico would also be gravely affected by the rising water levels. Despite a long history of archaeological research in the site core, much remains to be discovered about Yaxchilan. This ancient royal center, a favorite of modern tourists, would lose many of the fine palaces that attract visitors.

It is not the role of archaeologists to make government policies. But we can help to assess the potential threat to the cultural patrimony of Guatemala and Mexico, and help weigh the costs and benefits of any given development project in an archaeologically and environmentally sensitive area such as the Sierra del Lacandon. One of the primary goals of the Sierra del Lacandon Regional Archaeology survey is to provide a thorough and accurate assessment of the threat of flooding to the archaeological sites along the Usumacinta.