SOME INDIAN EXAMPLES
The
Nagarjunsagar is located near Nandikonda village of district Nalgonda in Andhra Pradesh. The main dam in located at latitude 160 34' 23"N
and longitude 790 18' 47"E.
It is an earth cum gravity dam and has been dubbed as the giant among the
Indian masonry dams. The height of the dam in 125m and cumulative length of the
crest is 4,865m. Out of this the
earthen part makes 3.415m, masonry part 978m (both non overflow sections) and
the spillway section being 472m. The
dam consumed 5,610,000M3 of concrete and masonry as well as
2,350,000M2 of earth. It has
been built on river Krishna for serving the purpose of irrigation and
hydropower. The Ogee type spillway has
26 redial gates each measuring 13.72X13.41m with a maximum discharge capacity
of 53,540m3/s. The reservoir
area is 285 km2 with its gross storage and effective storage
capacities being 11,550,000,000m3 and 6,990,000,000m3
respectively. The available draw down
is 24.38m. The catchment area is
2,15,192km2 with a mean annual runoff of 42,360,000,000m3. The catchtment area receives an annual
rainfall of 89 cm. The power plant is
conventional Fransis vertical types with a generation capacity of 700MW. The construction of the dam started in 1957
and it was commissioned in 1974. Figure
1 shows an image of the dam with X-section of earthen and concrete parts.