Introduction :
Need for Storm Water Drainage System
The flat terrain of Chennai City needs effecti8ve Storm Water Drainage System to prevent water stagnation in roads. The terrain of Chennai city is flat and average level of the land in the city is only 2.5m above the Mean Sea Level (MSL). Because of this flat terrain and partial coverage of roads with storm water drains, flooding and water stagnation happens in the city during the monsoons.
Statutory Provision
Section 176 of the Chennai City Municipal Corporation Act, 1919 entails the Corporation of Chennai to provide and maintain a Sufficient System of public drains throughout the city.
Storm Water Drain Department
In accordance with the Statutory rule, the Storm Water and Drain Department of Corporation of Chennai Constructs and maintains a network of Storm Water Drains and Canals.
Corporation of Chennai developed and maintains a Storm Water Drain network of 986 km in the city.
Corporation of Chennai, also maintains 16 canals of 28.64 km length criss crossing across the city.
Rain Water runoff gets drained through Storm Water Drain network & canals and reaches the Sea Via four Waterways-Otteri Nullah, Buckingham Canal, Adyar River and Cooum River-running across the city.
Construction of Storm Water Drain and Canals
Usually Storm Water Drain will be Provided in 12 m road and above. The minimum size of the drain will be 600X600 mm; the size will be designed depending upon the catchments area, land pattern and discharge. Under JnNURM Scheme, Storm Water drains are designed to relieve Water Stagnation in the Water logging areas irrespective of the width of the road. In Bus Route Roads Storm Water drains are provided usually in the footpath. The height of the drain top will be 6 inch above the road level. The Slab level should be lowered at all the entrance gates. The top Level of the Slab and man hole doors should be flush with the footpath Slab level. In all road crossing the Slab Should be flush with road level. The drain should be in straight alignment. SFRC (Steel Fibre Reinforced Concrete) Man hole door with chute pipes to be provided at every 5 m interval and perforated Man hole door and Silt trap pit to be provided at 30 m interval. PVC Pipes should be provided to accommodate the electrical and other utilities in Storm Water Drain crossings. The Canals are constructed with retaining wall which retains the earthern banks and gives an aesthetic appearance to the canal. The flooring facilities is such that men and machineries to carry out desilting works easily.
Improvement of Micro and Macro Storm Water Drainage network in Chennai under JnNURM
In order to alleviate a flooding comprehensive Proposal was prepared by the Corporation of Chennai in association with the Public Works Department (PWD). This proposal was approved by the State Level Sanctioning Committee, and subsequently appraised and Sanctioned by the Central Sanctioning and Monitoring Committee, Ministry of Urban Development, Government of India if four packages.
The details the four basins are tabulated below:
| Sl.No |
Name of Basin |
Chennai Corporation Component |
| 1 |
Northern Basin |
277.17 |
| 2 |
Central Basin |
261.11 |
| 3 |
Eastern Basin |
140.40 |
| 4 |
Southern Basin |
136.20 |
| |
Total |
814.88 |
The Government of India grant component under the JNNURM scheme is Rs.285.25 crore being 35% share, Government of Tamilnadu contribution is Rs.122.25 crore being 15% share of expenditure and the balance of Rs.407.44 crore being 50% share has to the borne by the local body i.e., Corporation of Chennai. The Administrative Sanction has been accorded for the project in G.O.(Ms).No.116, Municipal Administration and Water Supply Department dated 06.07.2009 by the Government. The Corporation of Chennai proposes to meet its share of Rs.407.44 crore by availing a loan of Rs.203.72 crores from Tamilnadu Urban finance and Infrastructure Development Corporation LTd. (TUFIDCO), Rs.150 crores from Tamilnadu Urban Infrastructure Financial Services Ltd., (TNUIFSL) and balance Rs.53.72 crores from Corporation of Chena’s own funds.
The Corporation of Chennai component of the project involves construction of 290 kilometers of new drains at an estimated cost of Rs.343.00 crore, re-modeling of 183 kilometers of existing micro drains at an estimated cost Rs.276.00 crore and improvement of 16 canals to a length of 29 kilometers at an estimated cost of Rs.160 crore. All the works in the four basins have been divided into 12 watersheds. Tenders were called for the works watersheds wise in 17 packages, tender settled, work order issued and the works are in progress.
|