I am presently living with my family in Panajachel, on the shores of Lake Atitlan in Guatemala. Lake Atitlan occupies a volcanic caldera that formed in a huge eruption about 80,000 years ago. The lake is about 20 km long, 10 km wide and 300 m deep, so even very simplistic volume calculations indicate a large volume of erupted material draping the surrounding region. There are villages scattered around the shore of the lake, wherever there is a foothold between the shore of the lake and the bounding cliffs.
One of the unusual features of Lake Atitlan is that while it is the center of a considerable watershed it has no surface outlet. Rainfall and surface streams flow into the lake, but outflow is only through groundwater flow that discharges to springs on the Pacific slope. Thus while the inflow to the lake is quite variable depending on weather conditions and especially the occasional hurricane that crosses the region, the outflow remains constant. In consequence the lake level is quite variable; during extended dry periods the lake level falls and during periods of higher than average rainfall the lake level can rise.
After decades of low and relatively stable lake levels, Lake Atitlan rose 3 meters in 2010, and another 2 meters this year. In other words the lake level has risen 15 vertical feet in the last 2 years! This has caused major problems for people living along the lakeshore. Everywhere one sees drowned houses and dock facilities, eroding banks, and flooded shorefront property.
Interestingly, the last lake level high stand (in the 1960’s as best as I can tell) is well within the memory of the older residents, but still people built on the lower shoreline with apparently little regard for the fact that the lake level might change. It’s not only in the U.S. that people have short functional memories!