Detail Hasil Pencarian
PENGARUH CHEKDAM DAN PENAMBANGAN PASIR TERHADAP MORFOLOGI SUNGA1 SENOWO KABUPATEN MAGELANG JAWA TENGAH (THE INFLUENCE OF CHECKDAMS AND SAND MINING ON THE MORPHOLOGY OF SENOWO RIVER IN MAGELANG REGENCY CENTRAL JAWA)
|Pengarang||:||Margiono, Soenarso Simoen, Suprapto Dibyosaputro|
|Jurnal||:||Teknosains 2000, XIII(2)|
|Summary / Kata Kunci||:||ABSTRACT
The. obyectives of the study were to observe, evaluate, and analyze: (1) sediment distribution from the SE-D, checkdam to the SE-C, checkdam; (2) volume of sand mining; and (3) effect of checkdam constructions and sand deposit mining on Senowo River morphology before and after the checkdams were built.
The study was conducted by mean of primary and secondary data collection. The secondary data included geology from geological map, rainfall, tranversal and longitudinal cross sections of the river before and after checkdam constructions, chekdam master plan, and volume of sand mining. Besides, literature study and field orientation were also carried out to fullfil incomplete data, Primary data included water height of every chekckdam for calculating flow discharge using weir formula, suspended and bed material samples at each checkdam required for total sediment discharge calculation, volume of sand mining, longitudinal and cross section measurement of the river from PA, to Pn for observing the change in the river morphology. Knowing the total amount of sediment discharge and sand mining volume the incoming and outcoming sediment could be calculated at every checkdam. Therefore, the river bed can be catagorized either in stable condition, degradated, or agradated condition. The result of the computation should also be accompolished by cross and longitudinal section of the river.
The result of the study showed that the flow discharge of the Senowo River from the upstream to downstream was getting lower. This was also shown by the incoming total sediment discharge distribution into the checkdam SE-D2 or the upper checkdam that decreased to the checkdam SE-Ci or the lower dam. Besides, sand mining in the upper checkdam SE-C2 and SE-C, gave rise to the decrease of sediment flow entering the downstream. Thus, the incoming total sediment discharge was lower than the outcoming one so that the river bed was degradated. The result of the analysis was supported by the physical appearance of the picture drawn in overlay. The result also showed that longotudinal and tranversal cross section of the river was seen to experience change in the river bed before and after the checkdams were built. The height of the river bed near upstream in all checkdams was the same as the weir checkdam height. Whereas in the downstream, all the checkdams experienced degradation. The flufial processes remaining to occur due to the checkdams and sand mining were the increase in back erosion, the lateral erosion of river back, the change in laminer into turbulent flow as a result of non compact material degradation with andesit stone remains, the formation of river bed braided pattern at the upstream checkdams experiencing agradation due to fine material sedimentation, and the development of sinousity pattern of the river marked by the occurrence of pools and bars.
Key words: checkdams, sand mining, river morphology.
|(tidak ada sitasi)|
|1.||Burgh,, Surface Hydrology, 1972|
|2.||C.T.Yang, Sediment Transport, 1996|
|3.||Douglas,, Erosion in the Sungei Gombak, 1968|
|4.||F.H.Schmidt,.H.A.Ferguson, Rainfall Types Based On Wet And Dry Period Ratios For Indonesia, 1951|
|5.||F.Nurrochmad, Laporan Akhir Studi Andal, 1996|
|6.||Japan International Cooperation Agency,, Perencanaan Bangunan Pengendali Sedimen, 1985|
|7.||R.K. R.E.W. Martin, Hydrology Water Quantity And Quality Control, 1997|
|8.||S.Soenarso, Sudarmadji, Darmakusuma,, Studi Hidrologi dan Pengukuran Hidrometri Waduk-Waduk Kecil di Bengawansolo, 1980|
|9.||Soewamo, Hidrologi: Pengukuran dan Pengolahan Data Aliran Sungai, 1991|
|10.||W.D.Thombury, Principles of Geomorphology, 1958|
|11.||W.Rahardjo, Sukandarrumidi, H.M.D.Rosidi, Peta Geologi Lembar Yogyakarta, 1977|