黄河长江是中国最宝贵的河道，长江成为中国内河航运的大动脉，长江长6300千米，水系河道5.73余万米。
B-Location I-Location I-Location I-Location O B-Location I-Location I-Location I-Location I-Location I-Location I-Location I-Location O B-Location I-Location O O B-Location I-Location I-Location I-Location I-Location I-Location I-Location I-Location I-Location I-Location O B-Location I-Location I-Location B-Metric I-Metric I-Metric I-Metric I-Metric I-Metric O B-Location I-Location I-Location I-Location B-Metric I-Metric I-Metric I-Metric I-Metric I-Metric I-Metric O