Kerala Rural Water Supply And Sanitation Agency Tender

Open well recharge unit is constructed as per the attached drawing in the annexure, by constructing a filter chamber after earth work excavation in circular shape with diameter 1.00m and depth 0.80m and placing 3 nos pre cast concrete ring 0.90m external diameter, 0.30m depth, with cover slab 1.00m diameter, 0.05 m thick ,filling with initial bottom layer 0.30m thick with 40mm coarse aggregate , adjacent layer 0.15 m thick with 20mm coarse aggregate, next layer 0.15m thick with 12mm coarse aggregate and top layer 0.10m thick with 6mm coarse aggregate, with 0.20m free space, including 0.10 m offset over ground level, with half split 110 mm diameter gutter pipe class 2 PVC (minimum length 15.00m) , down pipe & inlet pipe with 63mm class 2 PVC pipe ( minimum length 10 m) for roof top rain water collection towards filter chamber with a perforated portion for water discharge inside the filter chamber and with underground drain pipe connected to bottom layer of filter chamber with a perforated portion for water collection, for inward flow towards well, with suitable first flush sour arrangements for the disposal of initial rain water collected in the roof top.