Specifications Part 1 - Water Supply, Sewerage and Tube Well Works

5.7.3.6.1 The contractor shall develop the well with his own equipment by such as wouldextract maximum practical quantity of sand, drilling and unwanted fine materialin order to bring the well to maximum yield per m of draw down and to sandfree condition. Compressed air, surge block or pump may be used fordevelopment work. This work must be done in a manner that does not causeformation.5.7.3.6.2 The well shall be developed either by surging and agitating or by over pumpingand back washing with an airlift and high velocity jetting, etc. any otheracceptable method may also be adopted. This development process shall becontinued until the stabilization of sand and gravel pack has taken place.5.7.3.6.3 The development of the tube-well by over-pumping should be done at 15% to25 % higher discharge than the expected discharge from the tube-well. Thefinal discharge should be free form sand with a maximum tolerance of 20 partsof sand in one million part of water by volume after 20 minutes of starting thepump.5.8 Abandoned wells- A well declared as abandoned by the Engineer-in-chargedue to non-verticality, caving in or any other defects attributable to the poorworkmanship of the contractor, unsuitability of his equipment shall be termedabandoned well. No payment for this shall be due to the contractor. In such acase, the well assembly if lowered (complete or incomplete) will have to bepulled out and retrieved by the contractor at his own cost.5.9 Erection of Pump and Accessories.- The contractor shall install in the tube wellsuitable pump and motor and their accessories as may be supplied from subdivisionalstores by the Engineer-in-charge. The store will have to be lifted fromsub-divisional stores by the contractor, labour charges only will be paid forerection work. Contractor shall very carefully and diligently do the work oferecting all the components in the pump assembly such as:-(1) Pump.(2) Motor.(3) Column pipe, delivery pipes, bends, valves etc.(4) Electric water level guard with signal cable and electrode.(5) Air line.(6) Water level gauge.(7) Pressure gauge.(8) Irrigation panel.The column pipes should be truly vertical without any kinds and securelyjointed so as to preclude any chances of pump failing and resulting in the wellbeing declared as abandoned in cases of the pump cannot be retrieved.5.10 Disinfection:5.10.1 The well shall be disinfected as per requirements, after completion of test foryield. All the exterior parts of the pump coming in contact with the water shallUrban Administration & Development Department Page 214