KERALA WATER AUTHORITY DEPOSITE WORK OF KSCADC - WATER SUPPLY SCHEME TO COSTALWARDS OF ADIMALATHURA, POOVAR AND KARUMKULAM VILLAGES IN THIRUVANANTHAPURAM DISTRICT- Construction of 6.6m dia well, Sump cum pump house, Construction of Infiltration Gallery, Constructionof 1.033LL capacity OHSR and compound wall at Adimalathura,Supplying,laying,testing and commissioning of clear water pumping main using 100mm DI K9 from sump at Chappath to OHSR at Adimalathura, Supplying,laying,testing and commissioning of distribution network with 110mm and 90mm PVC 6kg/cm2, Providing 0.4mld microfilter in two units, Design,supply,erection,testing and commissioning of centrifugal pump set(2nos), Demolishing existing toilet block and interconnection works, Construction of chlorine room and toilet & Construction of shelter for microfilter NOTICE INVITING TENDER VOLUME - 2 SCOPE OF WORK OFFICE OF THE SUPERINTENDING ENGINEER P.H. CIRCLE KERALA WATER AUTHORITY OBSERVATORY HILLS, THIRUVANANTHAPURAM-695 033 KERALA STATE Tel.No . / FAX.NO. 0471-2322303 CONTENTS SCOPE OF WORK Page 2 STANDARD SPECIFICATIONS Page 8 SPECIAL SPECIFICATIONS Page 51 SPECIFICATION FOR OHSR,SUMP&PUMP HOUSE Page 55 1. SCOPE OF WORK 1.1 GENERAL INFORMATION 1.1.1 PROJECT AREA The project area comprises of the coastal wards of Adimalathura and Ambalathumoola of Kottukal Panchayath. 1.1.2 Project components 1.1.2.1 Construction of Open well (7.5m to 13m at Chappath) The location of site is at Chappath of Kottukal panchayath. There is an existing well of 6.6 m dia with 7.5m depth. The present project proposal is to deepen the existing well to 13.0 m 1.1.2.2 Construction of gallery The project include construction of infiltration gallery of size 8mx 4m with leading pipe of 110mm dia PVC pipe (8kg/cm2) 1.1.2.3 Construction of OHSR 1.033 LL The proposed site for construction of OHSR is at Adimalathura.The proposed site is handed over to KWA and is now under the possession of KWA. 1.1.2.4 Construction of compound wall of OHSR Compound wall is to be constructed for a length of about 40m length around the OHSR site 1.1.2.5 Supplying and laying clear water pumping main Supplying and laying of 100 mm DI K9 Clear water pumping main is to be carried out from sump at Chappath to OHSR at Adimalathura 1.1.2.6 Supplying and laying distribution network Distribution network with 110mm PVC and 90 mm PVC in various places of Adimalathura and Kochuthura areas are to be provided 1.1.2.7 Construction of sump and pump house Sump of 30000 litres capacity is to be constructed at Chappath and pump house is proposed to be constructed above the sump 1.1.2.8 Providing micro filter The proposal include design supply erection and commissioning of 0.4 mld capacity micro filter in two units 1.1.2.9 Demolishing existing toilet block and inter connection work Existing toilet block in the site for construction of sump is to be demolished. Interconnection of newly laid pipe with the existing line is to be carried out is also included in the scope of the work. 1.1.2.10 Supply and erection of pumpset Raw water pump set is proposed with 5 HP submersible pump set with 100% standby to pump raw water from collection well to micro filter and 10 HP centrifugal with 100% standby is proposed to pump clear water from sump to the OHSR. The raw water pump set to be designed to pump water from well to the micro filter is under the scope of the contractor. All connections as per the KSEB/KSEI norms. Necessary approvals from the authorities should be done by the contractor. All the necessary electrical & mechanical connections with all accessories , anchor blocks, sluice/NR valves, panel boards, starters, interconnections with MS pipes, suitable size cables etc complete are in the scope of the work 1.1.2.11 Construction of chlorine room and toilet Chlorine room to house the disinfection system is to be constructed at the site for clear water sump. Toilet for the operators is to be constructed at the site for clear water pump house at suitable location. 1.1.2.12 Construction of shelter for micro filter Shelter for housing the micro filter is be provided with sheet roofing 1.2 DETAILED SCOPE OF WORK The Detailed scope of work is as follows: 1.2.1 Construction of Open well (7.5m to 13m at Chappath) There is an existing well of 6.6 m diameter and 7.5 m depth. The scope includes deepening of the existing well to a depth of 13 m by sinking well , bailing out water , constructing the side wall with M30 concrete design mix with steel reinforcement (TMT) not less than 100 kg/ m3. and RCC bottom plugging and cover slab. Proper protection works may also be given for the existing well while carrying the work. Suitable earthen bund and bailing out is necessary because of water bodies on both side of the well. The steel reinforcement already provided in the existing well should be cleaned before the new work to ensure that there is no trace of rust remaining. MFL at the location of intake well is 99.50 m 1.2.2 Construction of gallery The scope of work comprises of providing bund, construction of gallery, supplying conveying filter media, supplying and laying lead/collecting pipe, packing media to gallery etc. gallery of size 8mx4m opposite to the existing well and below the Chappath bridge. The canal/ stream has to be provided with adequate earthen bund for deviating the flow and the excavation to be carried out to the line and level of the gallery alignment. The bund to be provided for a height of 2m, bottom width 1.5m, top width 1m, using earth filled gunny bags. Necessary bailing out has to be carried out during the course of construction. The bottom bed to be provided with firm flooring over a stabilized base layer (PCC 1:3:6) and above which the under drain perforated pipe to be laid with necessary gradient to collect the filtered water to the collecting chamber. The filter media to be packed, with length 8m, width 4m. The filter media of different grading as per specification of the gallery in the stream (40mm (50 cm) thick &20-12.5mm(30 cm thick)/10-6mm (30 cm thick) broken stones and pebbles respectively and coarse sand (50 cm thick) and fine sand( 50 cm thick) ) is to be packed in layers of the order of coarser media at bottom to finer media to the top of the gallery. The gallery should be constructed to ensure that unfiltered surface water cannot enter the raw water well. A mat floor in M30 mix with steel reinforcement not less than 100 kg/m3 is to be provided. RR masonry in CM 1:6 with leveling course on floor in PCC of 1:3:6 with 40mm broken stone is to be constructed around the gallery area. Supplying, seiving, stacking washing and spreading 40mm to 6mm broken stone, coarse sand and fine sand retained in 0.7 micron sieve in the gallery trenches as per standard norms including cost and conveyance of all materials and supplying and laying perforated 110 mm PVC (8 kg/cm2) lead pipe, minimum length- 76m with all specials connected to the gallery as per the direction of the departmental officers. The materials are to be tested at the expense of the contractor and got approved by the departmental officers. 1.2.3 Construction of OHSR 1.033 LL Construction of Over Head Service Reservoir (O.H.S.R), including survey, design, construction, testing and commissioning of elevated RCC reservoir with RCC staging consisting of columns with internal and external bracings having effective storage capacity of 1.033 Lakh Litre at Adimalathura in Kottukal panchayath along with all associated works viz: supply, installation of DI/C.I pipes, specials, valves etc. for Inlet/Outlet/ Overflow/ Scour/ Interconnection with existing system &Construction of compound wall and Gate.The ground level of the site is +98.610 m and OHSR inlet level is+110.610 m and out let level +107.610m. The land area is 1 ares and any structure inside the site is to be dismantled by the contractor without any extra cost. Use concrete mix of M30 grade for water retaining portions and M25 for other portions. The steel reinforcement for concrete for the construction of this OHSR shall be constructed using TMT bars only and the steel content should not be less than 120 kg/m3. Plastering in CM 1:3 12mm thick with water proofing admixtures is to be provided to the water retaining portions and for other portions CM in 1:4 is to be used. The plastered surfaces are to be painted with silicon and acrylic emulsion based water thinnable paint of approved brand for exterior and the water retaining portions are to be finished with water proofing cement paint. 100mm DI K9 pipe and 100mm sluice valve (minimum 3 nos) is to be provided for inlet and outlet arrangement. RCC staircase shall be provided as per approved drawing. GI hand rail using 40mm GI pipe is to be provided as hand rail to the stair case and in the landing area. Lettering in Black Japan paint should be given on the finished surface of OHSR as directed by the departmental officers. Water level indicator, lightening arrestor, vent cowl with mesh and 500mm dia CI M.H cover (minimum -4 nos), are to provided.