Regency Gunung Kidul is karst and hill area. The porosity of soil caused
the difficulty of obtaining surface water, thereby water shortage/ drought always
happens in dry season. In order to manage the water supply Sub System Bribin,
PDAM Gunung Kidul uses water from Underground River with 60 l/s. In fact ,
the discharge of pumping is not sufficient to serve approximately 75.000
consumers. The government’s plan in cooperation with Karlsruhe University to
use 80 l/s water from a new barrage in downstream Bribin river. The water would
be pumped by micro-hydro pump turbine and received by the new reservoir on
Kaligoro (RB-2) et + 406.225 m. Water from RB-2 would be distributed by
gravitation in order to make the cost cheaper. In order to find out the discharge
capacity of 80 l/s in serving the consumers, a study is needed. Due to the high
solvability of limestone and the potential contamination in the upstream of river,
the test of water quality has been conducted.
This study is a descriptive-qualitative research, giving a systematical
description about the water distribution network system with gravitation.To
determine inflow to RB-2 of Kaligoro reservoir, the routing reservoir has been
applied.
Result of water quality test shows that the quality of water in Bribin is
class II ,that means enough and available to drink.Water is distributed from RB-2
to R-4, R-5 and R-8 by gravitation method, the old network is still used.With 80
l/s discharge RB-2, the old system serves only 91% from consumers. Therefore, to
serve up 100% consumers, the discharge capacity should be increased 84 l/s.
Furthermore the volume of R-6 and R-4 should be enlarged 300m3
and 350m3
respectively.
Keywords: Water distribution, SBT. Bribin water, water quality, gravitation
system, minimum discharge of reservoir
