natural gas tanker on the rhine during drought

river lake reservoir sea shore water coast bay vehicle waterway mountain tree boating vacation boat cliff beach fjord mittelrheintal unesco world heritage site including loreley passage written lorelei older form oberwesel sankt goar goarshausen narrow reefs summer drought island inhabited birds still hard ship rocks color germany 2022 ships passing sandbanks heading flow groundwater recession low low-water discharge reef rhine entering south thorugh cargo close pass narrows lines parallel ting passed dutch dorught natural gas tanker