[1] Tributaries of the Mopan include Chiquibul Branch, Ceiba Grande, Salisipuedes, and Delores.

[3] Although the Mopan may contribute to downstream flooding during the rainy season, it responds much slower to rain storms than the other major tributary of the Belize River, the Macal.

Karper and Boles have asserted:[4] "The greater Mopan/Belize River Catchment provides a prime example of a watershed under stress from extensive non-sustainable agricultural practices that have occurred within the region over the past three decades."

From upriver to downriver, these include Ucanal, Arenal, Xunantunich, Actuncan, and Buenavista del Cayo.

Several of these sites and associated settlement areas have been studied as part of the Mopan Valley Archaeology Project.