The Construction and Validation of a Citizen Science Derived Global River Obstruction Database (GROD)

Human-made obstructions ranging from large dams to small, run-of-river structures are integral parts of river systems globally. These barriers alter the hydrology, geomorphology, and ecology of the river networks on which they exist. Despite their widespread occurrence and large impact, global datasets of river obstructions are limited to the largest dams. Regional databases are often more extensive but vary widely in quality and quantity of data, while also lacking representation in many regions and countries. Without a higher quality global dataset, we cannot fully understand the function and form of the world's rivers. Here we present the methods, validation, and preliminary U.S. results for a new Global River Obstruction Database (GROD). GROD contains information on the spatial location and class of significant obstructions existing on rivers ≥ 30 m in width across the globe. Collection of data for GROD uses simple techniques in the freely available Google Earth Engine Code Editor, making the project ideal for citizen science applications. Upon completion, GROD will provide novel information on thousands of global river obstructions with the potential for easy continued data acquisition and improvement with engagement from citizen scientists.