Abstract:
The Piano Key (PK) spillway constructed at Giritale
in 2013, is the first of its kind in Sri Lanka. A capacity
enhancement of the Giritale reservoir was required to overcome
the frequent water shortages during cropping seasons and
droughts. A decision was taken to enhance the capacity by
increasing the crest level of the spillway and a new spillway of the
PK type was introduced to satisfy this requirement. In this
research, a model study was done to improve the discharge
efficiency of such a PK spillway. Two models with different
sectional arrangements were fabricated and later these were
modified basically in crest shape. A total of four different models
were tested to simulate the flow behavior over the spillway and
the results were analyzed in order to find the head discharge
relationship. The research focused on how to obtain a suitable
PK model, among the models tested. The conclusion was that
model 1b (among the models 1a, 1b, 2a, 2b) was the optimum
model for the Giritale project.
