bridge brown drainage flood path rain river riverbank silt stairs steps walkway water austere bank bleak canada dour glacier harsh ice mountains natural nature peak range rock Rockies Rocky Mountains snow stern summit alluvial Asia big china distance distant enormous horizon island islet laden landscape large major Mud panorama vast yellow bare stark cliff foot mountain bay coast coastline everglades flats gulf Gulf of Mexico inlet mangrove mangroves mud flats ocean salt water saltwater sea sea weed seaweed tide