A PHYSICAL HYDRAULIC MODEL TEST TO SOLVE THE PROBLEM ON SPILLWAY DAM

Abstract

This research studies about the hydraulic performance and and the problem solving alternatives
of spillway design at Fila Tukutaha Dam, Alor District Indonesia. Flow water passing over the spillway of a
dam typically has a large amount of energy, must be dissipated safely before the floodwaters rejoin to the
natural river system. Therefore, energy dissipation takes place at the downstream end of the chuteway. The
stilling basin at the end of the chute way is commonly used to dissipate energy from the spillway and slow the
water velocity to protect the downstream river channel from erosion and damage. The methodology of
experiment consists of physical modeling in the Hydraulic and Coastal Engineering Laboratory of Civil
Departement, Sepuluh Nopember Institute of Technology. The discharge design was analyzed by hydrological
routing formula over the spillway. The methods include Bernoulli’s formula equation for the steeply sloped
channel, the standard step formula for calculating the energy equation on the transition channel, and the USBR
type 2 for designing the stilling basin. From the experimental result, cross-flow was reduced by adding the
hexagonal baffle block on the transition channel, and the effectiveness of stilling basin was occurred by placing
the abrupt rise in the downstream area.