Reconstruction of the flood-prone devastated city areas
Now that the centuries’ worst flood has receded, people shall be rebuilding their damaged houses in their respective sites. Some important points need to be considered to prevent recurrence of such an eventuality in future.
- There is no guarantee that floods of even worse magnitude may not visit the valley again. The global climate change is one of the major factors.
- Government seems to be contemplating to provide a parallel spill channel on the upstream side of the existing one, but that may be a long drawn affair as it shall involve land compensation etc. Besides this channel may also get defunct with the passage of time like the present one for want of its maintenance.
- The other ideal solution would have been to plan a new city on higher contours along foot-hills from Ganderbal to Harwan, Pandrethan, Khunmoh to Rajpora and on Karewas along southern foot-hills ensuring safety from river floods, proper drainage and fresh mountain breeze but again that may be a herculean task.
- People in present distress cannot wait for the long term measures of flood protection and they will soon resort to the reconstruction of their collapsed/damaged houses.
- /SMC must come up with the new building norms that are required in the flood prone areas to ensure the safety of lives of the inhabitants.
- Basement floors could be raised on RCC columns with ceiling level higher than the HFL, leaving the space for car parking etc. In fact such norms already provided for shopping complexes have been violated causing parking problems in the city. SMC must implement these norms strictly.
- Safe foundations need to be designed as per BIS specifications with the approval /check of SMC. In fact I found a ten story structure was stalled by Muncipal Authorities at plinth level in Abu Dhabi, the reason being provision of lesser steel than the approved/designed one.
- Due to land hunger possibility of vertical expansion as already advocated by me, of the city be considered seriously to tackle the future housing needs in view of multiplying population besides relocating the families of flood hit/prone areas.
- The partially damaged structures of the flooded area need to be inspected by an expert team to suggest measures for their retrofitting.
- Dewatering stations need to be lifted higher than the HFL of 100 year flood for making these functional during crisis.
- The plinths of all Govt. buildings/establishments in the flood prone areas need to be raised higher than the HFL. The basement floors could be used for car parking etc.
- Flood plain zoning is useful in reducing the damage caused by drainage congestion particularly in urban area where on grounds of economy and other considerations urban drainage may not be designed for the worst possible conditions and presupposes some damage during storms whose magnitude exceeds that for which the drainage system is designed.
- The steps involved in implementation of flood plain zoning measures could be as:
- Demarcation of areas liable to floods.
- Preparation of detailed contour plans of such areas to a large scale (preferably 1:5000) showing contours at interval of 0’3 to 0.5 meters.
- Fixation of reference river gauges and determination of areas likely to be inundated for different water levels and magnitudes of floods.
- Demarcation of areas liable to flooding by floods of different frequencies like once in two years, five, ten, twenty, fifty and hundred years. Similarly areas likely to be affected on account of accumulated rainfall like 5, 10, 25, and 50 years.
- Delineation of the types of which the flood plains can be put to in the light of © and (d) above with indication of safeguards to be ensured.
In the existing developed areas possibilities of protecting /relocation/exchanging the sites of vital installations like electricity substations/powerhouses, telephone exchanges etc. should be seriously examined so that these are always safe from possible flood damage. Similarly the pump stations of tube wells for drinking water supply should be raised above the HFL corresponding a 100 year flood.
Similarly possibility of removing buildings/structures obstructing existing natural drainage should be seriously considered. In any case unplanned growth shall be restricted so that no constructions obstructing natural drainage resulting in increased flood is allowed. In future the following regulations may be stipulated:
- Plinth levels of all buildings should be nearly 0.75 to one meter above the drainage/submersion levels.
- In the areas liable to floods all the buildings a stairway should invariably be provided to the roofs/attic floors so that temporary shelter can be taken there. The roof levels of the single story buildings and the first floor level in double story buildings should be above flood level of 1 to 100 frequency so that the human lives and the movable property can take temporary shelter there when necessary during the floods.
In the past CWC prepared guidelines in 1873-74 for flood plain zoning which were approved by Central Flood Control Board. CWC also prepared a model draft and circulated it in the Ministry of Irrigation in 1975, to all the states for enacting legislature. However the response from states except Manipur has not been encouraging. Manipur enacted a legislation in 1978 which came into force in 1985.
Flood proofing measures, help greatly in the mitigation of distress and provide immediate relief to the population in flood prone areas. It is essentially a combination of structural change and emergency action, not involving any evacuation. The technique adopted consists of providing raised platforms for flood shelter for men and cattle and raising the public utility installation above flood levels.
In case of urban areas, certain measures that can be put into action as soon as a flood warning in received involve:
Installation of removable covers such as steel or aluminium bulk heads over doors and windows or other openings keeping stone counters on wheels, closing of sewer well, anchoring machinery, covering machinery with plastic sheet, seepage control etc.
Flood proofing also tends to encourage persistent human occupation of flood plains.
Out of the non-structural measures “flood forecasting and warning” is considered as one of the most important, reliable and cost effective methods. CWC organizes flood forecasting at 157 stations in the country, of which 132 are for water stage forecast and 25 for inflow forecast for certain major reservoirs. The Flood Meteorological Offices (FMO) also provide information regarding general meteorological situation, rainfall of last 24 hours for different regions and range of quantitative precipitation forecasts for various river basins to the respective flood forecasting centers of CWC. All the data is simultaneously transmitted to the circle headquarters supervising forecasting works for overall security, monitoring, analysis and compilation. The final forecasts are then transmitted to the administrative and engineering authorities of the state and other user agencies connected with flood protection and management work on telephone or by special messenger/ telegraph/ workers depending upon local factors like vulnerability of the area and availability of the communication facility etc.
The Master Plan 2000-2021 recommendations for river Jhelum were:
- All Doongas and houseboats be shifted upstream of Padshahibagh or downstream of Chattabal. The tourist oriented houseboats could be shifted to Dal or Nigeen area.
- Encroachments made on the banks of the river and all three Khuls- Kuta Khul, Soner Khul and Watel Khul be cleared en-masse.
- Development of river fronts will involve clearance of some sites for development of parks.
- To stop garbage dumping from Lal-Ded Hospital, incineration plant be installed there.
- Wherever possible Agriculture department should level the disused brick kiln sites on either side of cement bridge and use the same for growing vegetables.
- Shikara ghats be constructed at appropriate points, connected with pucca stairs to nearby roads.
- While according permission for building construction on river and nallah fronts, no part of the building is protruded towards the river and nallah boundaries or over their embankments.
- Problem of river discharge on river Jhelum be solved as it has assumed serious dimensions. Over the past fifty years, river Jhelum and spill channel has heavily silted up. It was understood that the flood control problem was being entrusted by I&FC Deptt. to some consultancy firm, hence the problem of siltation, dredging, gradient, velocity etc. shall be dealt with. Some suggestions included to redesign flood absorption basin from Kandizal to Padshahibagh saving the railway line and Mahjoor nagar area. Beds of river Jhelum and spill channel be deepened to increase the discharge capacity and ensure the minimum draft required for mechanized water transport. Gradient of spill channel be increased up to the permissible limits. Weir at Chattabal be redesigned. Navigational channel of the lock gate at weir site be desilted to make it functional.
However the Master Plan 2000-2021 has also got entangled in the cobweb of red-tape like other similar vital issues which ultimately land us into a chaotic situation like the recent one.