1882-1981 556 africa alluvium bedload biography bretz bridges coastchanges coasts columbiaplateau congresses congrès debrisavalanches desertification designandconstruction earthsciences environmentalaspects eolianprocesses evolutionarypaleoecology experiments floods friction geography geologists geology geomorphology glaciallandforms géomorphologie highwayengineering kurdufānal-shamālīyah landforms landsatsatellites materials mechanicalwear morphotectonics physicalgeography pumpingstations remotesensing rivers roaddrainage roads s623 science sedimentationanddeposition sediments(geology) sedimenttransport soilerosion structural sudan sédimentation(géologie) testing unitedstates watersheds wetlands érosion