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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16.7 The reduced level at different points of intake well and<br />
reservoirs/dam.<br />
High flood level : 1577.00 m<br />
Crest Level of Dam : 1562.00m<br />
Minimum water level : 1562.00m<br />
Pumps floor level : 1585.60m<br />
Discharge gallery level : 1583.20m<br />
Centre line of upper level intake port opening : 1575.00m<br />
Centre line of middle level intake port opening : 1567.00m<br />
Centre line of lower level intake port opening : 1562.50m<br />
16.8 For design of intermediate stage RCC Sump. The following factors are<br />
to be considered.<br />
i) Intermediate stage RCC sump is proposed to be constructed at a distance of about<br />
750m from the intake well and pump house. The RCC sump shall collect water lifted by<br />
the intake well pumps and shall have a storage capacity of 839.75 KL.<br />
ii) Since the sump is designed for the ultimate requirement and that 6 nos. of pumps<br />
are proposed to be installed in the ultimate stage, the RCC sump shall be of twin circular<br />
type to facilitate placement of suction pipes for 6 pumps.<br />
iii) The sump shall be constructed at the same level with that of the pumps house and<br />
shall have a height of not less than 3.3m to ensure pumps are installed with positive<br />
suction. The well is to be constructed with RCC of M-25 grade concrete and HYSD/TMT<br />
bars for reinforcement.<br />
vi) Avoidance of sudden change in the direction of flow by provision of a stilling<br />
chamber to reduce the velocity gradually to about 0.3 m/s near the suction bellmouth.<br />
v) Avoidance of dead spots by keeping rear clearance from the center line of the<br />
pump.<br />
vi) Avoidance of mutual interference between two adjoining pumps by maintaining<br />
sufficiency clearance.<br />
(vii) Avoidance of dead spots at the suction bellmouth by maintaining the bottom<br />
clearance.<br />
viii) Provision for adequate submergence of the inlet of pump under the LWL, so as to<br />
prevent entry of air during draw down and to satisfy NPSHr.<br />
ix) Provision for overflow arrangement from the inlet stilling chamber.<br />
x) Provision for drainage system from both inlet and main chamber of the sump.<br />
xi) Provision for free board.<br />
DTS : Detailed Tender Specification. Page 161
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