Citizen and Satellite Measurements Used to Estimate Lake Water Storage Variations

Of the roughly 20-40 million lakes in the world larger than 0.01 km2, perhaps a few thousand receive regular water level monitoring, and only approximately a thousand are included in the largest lake level databases. The prospect for on-the-ground, automated monitoring of a significant fraction of the world's lakes is not high given the considerable expense involved. In comparison to many other measurements, however, measuring lake water level is relatively simple under most conditions. A staff gauge installed in a lake, essentially a leveled ruler, can be read relatively simply by both experts and ordinary citizens. Reliable staff gauges cost far less than automated systems, making them an attractive alternative. However, staff gauges are only effective when they are regularly observed and when those observations are communicated to a central database. We have developed and tested a system for citizen …