KAJIAN PANJANG LONCATAN HIDROLIK PADA MODEL FISIK KOLAM OLAK BENDUNGAN KRUENG KLUET KABUPATEN ACEH SELATAN

The spillway's major structure, stilling basin, serves 25, 50, 100, and 1000 years were observed and measured. The tests were conducted on two types of structures: original series (S 0 ) and final series (S 1 ). The United States Bureau of Reclamation (USBR) III type is used in the stilling basin S 0 . While S 1 is made by adding an adversed slope with a slope of 1:2 downstream and lowering its bottom elevation to a depth of 4 m. Observation results show that the S 1 model produces an average ratio of Lj/y1 (jump length) < 20-40% shorter than the S 0 model. In addition, the pattern of energy dissipation that occurs in S 1 tends to increase by increasing Q with the maximum energy loss (∆E/y1) obtained is 42.6 (greater than that produced by S 0 ). So it can be concluded that the bottom and downstream of the stilling basin mode S 1 is safer than the model S 0 .