Management of storm water drainage in Chandigarh

Abstract

Storm water management involves the control of runoff from precipitation. Due to developmental activities impervious surface is increasing which prevent the infiltration of rainfall into soil. Hence, volume and rate of runoff both substantially are increasing. Pervious concrete pavements has potential to reduce runoff effectively by allowing water from precipitation through it and temporary storing storm water and releasing it slowly to ground after storm subsides. Pervious concrete pavements are traditionally used in parking areas, areas with light traffic, residential streets and pedestrian walkways. Chandigarh is rapidly growing city and in last decade (2001 to 2011), its population growth rate was 17.19 % and its population density was 9262/km2 and average annual rainfall is 1110.7 mm. So more runoff is generated and existing storm water drains in Chandigarh in some areas, are not sufficient due to rapidly increasing paved area. Storm water drains are not capable in draining storm water so ponding occurs in various places. Pervious concrete pavement could be an alternative to manage storm water in Chandigarh. Pervious concrete pavements design depends upon native soil properties such as infiltration capacity and other properties also. For management of storm water, five sectors of Chandigarh were selected viz. 12, 34, 26, 17 and 14. Areas were calculated for selected sectors where pervious concrete can be provided e.g. Parking areas. As pervious concrete is to be used for parking areas it should be of strength range 15 to 20 MPa which is achieved by design mix prepared. Compressive strength and permeability for design mix pervious concrete were found to be 19.33 MPa and 0.89×10-3cm/sec, respectively. A model was fabricated to find out hydraulic response of pervious concrete pavement for different intensities applied for different durations. Pervious concrete pavement effectively managed rain events and could be able to store more than 42.16 % of rainfall and release it slowly from the pavement structure. Volume discharged from pervious concrete pavement ranged 42.16 % to 88 %. Runoff generated in selected areas was calculated before and after providing pervious concrete. It was seen that there was a decrease in runoff by 7.54 % to 15.30 % when pervious concrete provided. For the design of pervious concrete pavements stone reservoir depths were found to be 448.7 mm, 450 mm, 441 mm, 443 mm and 446 mm for sector 12, 34, 26, 17 and 14, respectively.