PACKAGE : I Bid Document VOLUME : II - Public Health Engineering
PACKAGE : I Bid Document VOLUME : II - Public Health Engineering
PACKAGE : I Bid Document VOLUME : II - Public Health Engineering
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Chapter - 16<br />
Technical specification for Raw water intake, pump house &<br />
approach bridge and Raw water intermediate RCC Sump &<br />
Pump house.<br />
16.1 Introduction.<br />
Shillong is the capital of the State of Meghalaya. The supply of water to Shillong is<br />
from the GSWS Water Works at Mawphlang located about 24 Km away. The<br />
source of the water works is mass gravity concrete dam constructed across the river<br />
Umiew near Mawphlang about 6.5Km from Mawphlang under<br />
GSWSP (Phase I & <strong>II</strong>).<br />
A Twin RCC Intake well of 8m internal diameter and 36m in height was<br />
constructed with pump house at the top by the bank of the river in 1985-1986. Each<br />
of the twin intake well is connected with 2 nos. inlet M.S. pipe of 600mm at<br />
2 different levels for drawing of water from the run-off the river into the well for<br />
pumping by 6 nos. vertical turbine pump installed in pump house. The pump floor<br />
level, discharge gallery and R.L. of sluice gates for entry of water into the intake<br />
well were designed keeping inview the HWL on post construction of dam proposed<br />
to be taken up at a later stage.<br />
The mass gravity concrete dam was subsequently taken up for construction in 1997<br />
and completed in 2003. Following the construction of dam and consequential rise in<br />
water level, the original 2 nos. MS inlet pipes to each of the twin intake well were<br />
closed allowing water to enter into the intake well through the sluice gate fixed at<br />
higher level in the intake well wall. Presently about 51.30 MLD is drawn from the<br />
dam in 2 stages of pumping system for supply to Shillong after treatment.<br />
16.2 Intent and requirement.<br />
The intent of this tender is to construct additional RCC intake well with pump house<br />
and an approach bridge of about 40m in the vicinity of the reservoir and adjacent to<br />
the existing intake well including construction of intermediate stage RCC sump and<br />
pump house for the purpose of drawal of additional quantity of water to meet the<br />
increasing demand for the present and future requirement.<br />
DTS : Detailed Tender Specification. Page 157
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