Mitigation Strategy-SOP

The management of urban flooding is an emerging subject, and as such it has to be treated holistically in a multi-disciplinary manner. There are many issues that need to be considered in order to develop sound, reliable and most representative urban flood/disaster management strategies.

The Standard Operating Procedures (SOP) covers the following three phases of disaster management for effective and efficient response to urban flooding:

Pre-Monsoon Phase:

• Preparedness - Planning for Disaster Reduction focuses on plans to respond to a threat or occurrence of urban flooding. It takes into account an estimation of emergency needs and identifies the resources to meet these needs. It also involves the preparation of well-designed plans to structure the entire post-flooding response, and familiarizing the stakeholders, particularly the communities through training and simulation exercises.

During Monsoon Phase:

• Early Warning - This phase will include all necessary measures to provide timely, qualitative and quantitative warnings to the urban flooding based on the intensity of rainfall to enable various agencies to take preventative measures for preventing loss of life and reducing loss/damage to the urban infrastructure. On the occurrence of urban flooding and threat thereof, all the concerned Departments/Agencies need to be act for initiating immediate necessary follow up action.

• Effective Response and Management - The Response Phase is the actual implementation of the disaster plan. Disaster response is the organization of activities used to respond to the event and its aftermath. The Response Phase focuses primarily on emergency relief: saving lives, providing first aid, minimizing and restoring damaged systems (communications and transportation), meeting the basic life requirements of those impacted by disaster (food, water, and shelter), and providing mental health and spiritual support and comfort care.

• Relief planning and execution - This phase will include all necessary measures to provide immediate relief and relief / assistance to the affected people in terms of their essential needs of food, drinking water, health and hygiene, temporary shelter, traffic control, wherever the areas are under heavy inundation etc.

Post-Monsoon Phase:

• Restoration and Re-habilitation -This phase will include all necessary measures to stabilize the vulnerable situation and restore the utilities. This phase is to establish a programme to restore both the disaster site and the damaged materials to a stable and usable condition.

National Disaster Management Authority (NDMA) has prepared National Disaster Management Guidelines: Management of Urban Flooding in September, 2010. The said guidelines suggest establishment of Urban Flooding Cells at State Nodal Departments and ULBs.

Alerts and warnings

For the purpose of dissemination of alerts, a uniform system has been devised by Ministry of Home Affairs categorizing alerts in stages – Yellow, Orange and Red.

• Yellow : to be communicated to Emergency Operations Centres (EOC) through EMS.
• Orange :to be communicated to EOC and State Disaster Management Authority (SDMA) @ 12 hourly updates.
• Red : to be communicated to EOC, DEOC /SDMA, NEOC @ 3 hourly updates or more frequent.

Yellow Stage

• Alerts will be transmitted to Branch Officer, Disaster Management (DM).
• Alert messages will also be sent to the concerned Departments/ Organizations/ Agencies rendering Emergency Support Functions (ESF) for their information and necessary action where required.
• To all designated Nodal Officer of DM in different ESF Departments.
• Alerts would also be communicated to the vulnerable communities through the available means.

Orange Stage

• All Departments/Agencies will be required to transmit 12 hourly updates.
• All Departments/Agencies generating alerts will be required to transmit information to IC, SEOC and DEOCs within 30 minutes of the receipt of information regarding with up gradations.
• Alerts will be transmitted by IC, SEOC to all designated Nodal Officer (DM) in ESF departments to be ready with all necessary and standby arrangements.
• IC, SEOC will transmit alerts to the concerned Districts authorities.
• Alerts would also be communicated to the vulnerable communities through the available means.

Red Stage

• All concerned departments/organizations/agencies will be required to transmit alerts to IC, SEOC and DEOC immediately on receipt of information and not later than 30 minutes of the event.
• IC, SEOC will constantly monitor the position and transmit 3 hourly updates to all designated Nodal Officer (DM) in all ESF Departments to be ready with all necessary standby arrangements.
• IC, SEOC will transmit alerts to the concerned Districts authorities. The district EOC would intimate and alert all concerned.
• Alerts would also be communicated to the vulnerable communities through the available means.

Central Water Commission (CWC) has developed a network of flood forecasting stations to issue Daily Flood Bulletins to all designated authorities/agencies of the Central Government and State Governments/District Administration for all major river basins as the following:

Category	Description	Stage
IV	Low Flood (Water level between Warning Level and Danger Level)	Yellow
III	Moderate Flood (Water Level below 0.50 m less than HFL and above Danger Level)	Yellow
II	High Flood (Water Level less than Highest Flood Level but still within 0.50 m of the HFL)	Orange
I	Unprecedented Flood (Water Level equal and above Highest Flood level)	Red

However, typically flood warnings in local area may be categorized as per the following:

Category	Description	Stage
IV	Sudden flash flood due to sporadic heavy downpour	Yellow
III	Water logging in all arterial and sub-arterial roads and intersections	Yellow
II	Breach of river embankments /flooding of river flood plains	red
I	Inundation/water logging in the buildings-residential and other buildings	Red

Source: Modified based on the categorization of Warning given in Himachal Pradesh "Standard Operating Procedures for Responding to Disasters, 2012"

Nodal Agencies for Early Warning

Following are the Nodal agencies in the Government of India mandated for early warning:

Urban Flooding	Agencies
Rainfall	Indian Meteorological Department
River Floods	Central Water Commission/State Irrigation Department
Drainage	Municipal Corporation / PWD
Geomorphologic features	Geological Survey of India
Mapping	National Remote Sensing Centre
water Logging	PWD Department/Jal Board/Municipal Corporations

These agencies shall be responsible for keeping track of developments in respect of urban flooding assigned to them and inform the designated authorities/ agencies at National, State and District levels about the forecasting/advance warning on urban flooding.

Other parameters to be considered for mitigation

The geographic location and physiographic conditions of cities are to be taken care of while devising the city specific SOP. Some such major considerations are as given below:

Coastal cities

Floods in coastal cities are compounded by high tides depending on the time of the event.

• Short term : Clearing of natural and engineered drainage system from silt and municipal solid waste.
• Medium/Long term : Plans to include emphasis on rain water harvesting at household & neighborhood level.

Inland cities

Immediate water discharge and prevention of water logging is a challenge in inland cities.

• Short term : Clearing of natural and engineered drainage system from silt and municipal solid waste.
• Medium term : Catchment areas with natural gradient towards a nearby lake / river to be restricted from development.
• Long term : Afforestation for reduction of rainwater runoff. Rejuvenation and conservation of ponds, tanks and lakes with interconnections

Hill towns

Challenged with very high runoff, short flow duration and high scouring on account of slope, floods may also trigger mud flow and land slide.

• Short term : Clearing of natural drains from municipal solid waste and other dumping.
• Medium term : Flood plains to be kept construction free by notifying “Conservation zones” along the river channels, suitably demarcated and with strict compliance/enforcement. Natural drain channels to be kept obstruction free at all times. Digital Flood modeling to be attempted for different scenarios of precipitation.
• Long term : Afforestation is highly desirable along the hill slopes to reduce impact of flood and prevent landslides.

Cities along rivers

Challenged with shifting water course in the middle and lower Gangetic plains or unexpected high water discharge in-course.

• Short term : To undertake dredging and de-silting to keep the bed clear for volume flow.
• Medium term : Building byelaws may incorporate provisions for construction on higher plinth or stilts as traditionally practiced. Vulnerable areas be demarcated and be kept construction free.
• Long term : Natural and manmade water bodies should be well conserved, rejuvenated and interconnections be established for efficient flood control.

Cities near dams and reservoirs :

Requires selective actions from the measures mentioned above along with coordination with the reservoir management agencies.

Source : Urban Flooding : Standard Operating Procedure- Ministry of Urban Development, GoI