Experimental study on sediment trap capacity of ring net barrier with varying basal openings
Chitra Widyasani Surya Putri (a*), Djoko Legono (a), Adam Pamudji Rahardjo (a), Ardian Alfianto (b)

(a) Departement of Civil Engineering and Environment, Gadjah Mada University, Jalan Grafika No 2, Yogyakarta 55281 Indonesia
*chitrawsp[at]gmail.com
(b)Sabo Research and Development Office, Jalan Sabo No 1, Yogyakarta, Indonesia

Abstract

Ring net barrier is originally developed as a protection from rockfalls, but some countries have proven that this type is also effective in trapping debris flow sediment. In Indonesia, ring net barrier as sediment control is applied by Sabo Research and Development Office in Lumajang, East Java on a slope of 3,48o and is placed 0,8 m above river bed. To identify the optimal position of the basal opening, a hydraulic flume test is performed with a scale of 1:60, 0.6 cm of diameter of ring and a variety of discharge (11 l/s, 8 l/s, and 1.8 l/s). The amount of sediment consentration is 10% and flow time of 144 seconds. The basal opening position is varied from the same as river bed surface, placed as deep as 1.66 cm and 3.2 cm The results show that ring net can retain sediment more if the net is placed as deep as 3.2 cm. Therefore the sediment trap capacity of ring net barrier that is applied in Lumajang can be optimized by shifting the basal opening position to 1.92 meters deep from the river bed surface.

Keywords: ring net barrier; basal opening; sediment trap capacity

Topic: Civil Engineering