Abstract
To help store water, facilitate navigation, generate energy, mitigate
floods, and support industrial and agricultural production, people have
built and continue to build obstructions to natural flow in rivers.
However, due to the long and complex history of constructing and
removing such obstructions, we lack a globally consistent record of
their locations and types. Here, we used a consistent method to visually
locate and classify obstructions on 2.1 million km of large rivers
(width ≥ 30m) globally. We based our mapping on Google Earth Engine’s
high resolution images from 2018–2020, which for many places have
meter-scale resolution. The resulting dataset, the Global River
Obstruction Database (GROD), consists of 29,877 unique obstructions,
covering six different obstruction types: dam, lock, low head dam,
channel dam, and two types of partial dams. By classifying a subset of
the obstructions multiple times, we are able to show high classification
consistency (87% mean balanced accuracy) for the three types of
obstructions that fully intersect rivers: dams, low head dams, and
locks. The classification of the three types of partial obstructions are
somewhat less consistent (61% mean balanced accuracy). Overall, by
comparing GROD to similar datasets, we estimate GROD likely captured
90% of the obstructions on large rivers. We anticipate that GROD will
be of wide interest to the hydrological modeling, aquatic ecology,
geomorphology, and water resource management communities.