| Summary: | In Yogyakarta and south part of Central Java province, there are ten rivers namely Tipar, Ijo, Telomoyo, Lukulo, Wawar, Cokroyasan, Bogowonto, Serang, Progo and Opak rivers. The river mouths are blocked by sand dunes during dry season. This condition reduces the capacity of the rivers and causes flooding in the upstream area during wet season.
The study is done to alleviate that problem. Alternative strategies and measures for improvement of the river mouths are discused based on flood severity, river mouth condition, and structure cost. Elimination of the sand spit at river mouths could be achieved by (I) annually opening the river mouths at the sand spit at the end of dry season by farmer society or excavator, (2) constructing a river mouth training wall at the river mouths. or (3) constructing two jetties at both sides of the river mouths.
The study leads to recommending strategies or measures for improvement of each river mouth. For the Wawar river mouth, construction of a west river mouth training wall is recommended, while two long jetties are proposed for the Serang river. These jetties can also be used as break water of fishing port, thus it holds a high economical value. Whereas for other river mouths, opening the sand spit can be done by farmer society or excavator.
Key Words: River mouths - civil engineering
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