ASSESSMENT OF FLOOD RISK OF SECONDARY TOWN IN …€¦ · midterm return flood will affect 26.03% area and short term return flood will affect 22.29% area of the study area. On the

Proceedings on International Conference on Disaster Risk Management,

Dhaka, Bangladesh, January 12-14, 2019

Page | 484

ASSESSMENT OF FLOOD RISK OF SECONDARY TOWN IN BANGLADESH:

A CASE STUDY OF CHHATAK POURASHAVA

Farzana Afroz1 and Mohammad Atikul Islam2

ABSTRACT

The impact of the seasonal flood is very severe at many secondary towns in Bangladesh. Considering that,

the principle goal of this study is to assess the flood Risk of secondary town in Bangladesh. Chhatak

Pourashava has been taken as a case study which is located in Sunamganj district, one of the main flash flood-

prone areas. To achieve this goal, at first identify the existing land use and flood risk based on the GIS contour

data. Then the area has been broadly classified into short-term return flood affected area, mid-term return

flood affected area and long-term return flood affected area depending on the flood risk and water level of

different return period of the flood. Finally, the analysis reveals that total 448.53 (93%) acre agriculture areas

will be affected by short term return flood. Long term return flood will affect 78.82% agricultural use followed

by the 60.72 acres (6.6%) residential area, manufacturing and processing activity covers 48.44 acres (5.32%)

area. Mid-term return flood will affect maximum 89.7% area in agriculture use where 3.98% manufacturing

and processing activity use and 3.16% area in residential use. The appropriate measures of disaster

management in urban planning will reduce its vulnerability of different disasters to make the secondary town

of Bangladesh more sustainable.

Introduction

Floods are annual phenomena with the severe occurring during the months of July and August. Seasonal flood

is a very common and familiar phenomenon of Sunamganj Upazila under Sunamganj district (CDMP, 2014).

It is same for Chhatak Pourashava, the secondary town of Sunamganj district. In the rainy season, flood is

occurred in this area due to heavy rainfall and upstream water from Meghalaya Hill. It damages in the sector

of agriculture, fishery, livestock, infrastructure, homes, education, health, trees etc. Though it occurs every

year, a seasonal flood of 2004 and 2012 were devastating (CDMP, 2014). In the flood of 2006, about 91 %

of households were affected by flood at Chhatak Pourashava. Most of these affected households lost crops.

Total 31.51 % lost crops valuing up to Tk10000, followed by 42.37% up to 20000. Total 27.12 % people lost

their crop valuing more than Tk. 20000 (UTIDP, 2010). In future, flash flood may happen frequently due to

climate change which can be severe for secondary cities. Agriculture sector may have huge damage from this.

It may have a negative impact on the livelihood of the people. Bangladesh tries to live with flood as well as

other disasters with structural and non-structural measures. So, it is crucial need to know the flood risk for

reducing the damages. Considering that, this study aims to assess the flood Risk of Chhatak Pourashava, one

of the flood-prone secondary towns in Bangladesh. It will assist to ensure urban resilience and reduce the

vulnerability of this Pourashava.

Methodology

Different impacts of the flood have been prepared based on the contour data of Chhatak Pourashava and the

flood level data (highest water level) of the different time period in Sunamganj Station at Surma River as

Surma River is passing through the Chhatak Pourashava and Sunamganj Station is the nearest station on this

river from the study area. Recorded maximum flood level 9.46 m (Flood Response Preparedness Plan of

Bangladesh, 2014) is considered as long term return flood level (for 100 years return); the flood level of 1988

is 9.03 m considered as mid-term return flood level and the flood level of 1998 is 8.90 m considered as short-

term return flood level for the analysis of flood affected area.

Analysis and Findings

Depending on the water level of different return period of flood the study area broadly classified flood affected

area and flood free area. From the analysis, it is found that total 1419.31 acres land which is 45.86% total

area of Chhatak Pourashava and its proposed extended area will affect by the long term return floods. The

1Jr. Urban Planner, Sheltech Consultants (Pvt.) Ltd., Dhaka, Bangladesh. 2Manager, Sheltech Consultants (Pvt.) Ltd., Dhaka, Bangladesh.

Email of Corresponding Author – [email protected]



Page | 485

midterm return flood will affect 26.03% area and short term return flood will affect 22.29% area of the study

area. On the other hand, 64.60% area will be remained flood free during short term return flood, followed by

midterm flood 60.86% and 41.02% in long term return flood. Table 1 and Figure 1, 2 illustrates the details.

Table 1. Flood Risk Scenario at Different Return Period Floods at Chhatak Pourashava and its proposed

extended area

Flood Affected Area Flood Free Area Type Area(acre) % Type Area(acre) %

Short-term return 689.76 22.29 Short-term return 1999.10 64.60

Mid-term return 805.38 26.03 Mid-term 1883.48 60.86

Long-term 1419.31 45.86 Long-term return 1269.55 41.02

Main Flood Flow Channel 380.37 12.29 Auxiliary Flood Channel 25.39 0.82

Source: Calculated by Author, 2016 based on the GIS data of UTIDP, 2010 and flood level data from Flood

Response Preparedness Plan of Bangladesh, 2014

In the case of existing land use, total 448.53-acre agriculture areas will be affected by short term return flood

which is near to 93% of the total affected area of short term return flood. In case of long term return flood

maximum affected area will be in agricultural use 78.82% followed by the 60.72 acres (6.6%) residential

area, manufacturing, and processing activity will be covered by 48.44 acres (5.32%) area within the study

area. In the case of mid-term return flood maximum, 89.7% affected area will be in agriculture land use. It

will be followed by 3.98% manufacturing and processing activity use and 3.16% area will be in residential

use. A detailed scenario is given in the following Table 2 and Figure 1 and 2.

Table 2. Flood Risk Scenario at Different Return Period of Floods on Existing Land Use

Existing Land

Use

Short-term return flood Mid-term return flood Long-term return flood

Area (acre) % Area (acre) % Area (acre) %

Agriculture 448.53 92.52 505.76 89.7 718.11 78.82

Circulation Network 1.31 0.27 2.06 0.37 10.52 1.16

Commercial Activity 0.09 0.02 0.101 0.01 1.28 0.14

Community Service 0 0 0.008 0 1.05 0.12

Education and

Research 0.50 0.11 0.52 0.09 1.27 0.14

Governmental

Services 0.28 0.06 0.55 0.1 4.36 0.48

Manufacturing and

Processing Activity 11.69 2.41 22.44 3.98 48.44 5.32

Miscellaneous 0.05 0.01 0.16 0.03 0.66 0.07

Mixed Use 0.10 0.02 0.11 0.02 0.27 0.03

Recreational

Facilities 0 0 0 0 0.51 0.06

Residential 13.03 2.69 17.83 3.16 60.72 6.66

Service Activity 0.0001 0 0.001 0 0.46 0.05

Urban Green Space 0.018 0 0.08 0.01 5.57 0.61

Vacant Land 2.23 0.46 5.73 0.83 37.26 4.09

Water body 6.95 1.43 8.48 1.5 20.60 2.26

Total 484.79 100 563.84 100 911.07 100




Page | 486


The total length of road network in Chhatak Pourashava is 68.7180 km. Among them, 23.8650 km is katcha,

0.972 km semi-pucca and 43.8810 km pucca road (UTIDP, 2010). A mentionable number of roads are in

thread of flood risk. Total 2058.98-meter road will be affected by short term return flood, 3107.1-meter road

will be affected by mid-term flood and 13850.63-meter road will be affected by long term flood. Detailed

scenario is given in Table 3.

Table 3. Type of Flood Risk on Existing Road of Chhatak Pourashava

Type

Short-term return

flood Mid-term return flood Long-term return flood

Length (m) % Length (m) % Length (m) %

Katcha Road 683.05 33.17 1250.49 40.25 5578.76 40.28

Pucca Road 1375.93 66.83 1856.52 59.75 8151.37 58.85

Semi pucca Road 0 0 0 0 120.5 0.87

Total 2058.98 100 3107.01 100 13850.63 100



Pourashava has 5730 structures which include 2350 katcha, 1671 pucca structure and rests 1704 semi pucca

structures (UTIDP, 2010). Considering flood risk within the study area total 111structures will be affected by

short term return flood, 173 structures were affected by mid-term return flood and in case of long-term return

flood, 825 structures will be affected. Detailed scenario of type wise flood risk structure is given in Table 4.

Table 4: Type Wise Distribution of Flood Risk Structures

Type

Short-term return flood Mid-term return flood Long-term return flood

No. % No. % No. %

Katcha 62 55.86 104 60.12 442 53.58

Pucca 22 19.82 33 19.08 197 23.88

Semi Pucca 27 24.32 36 20.81 186 22.55

Total 111 100 173 100 825 100





Page | 487

Figure 1. Flood Risk in Chhatak Pourashava



Page | 488

Figure 2. Flood risk with respect different return period



Page | 489

Conclusions

This research paper analyzed flood vulnerability within Chhatak Pourashava. Findings of this research show

45.61% of Chhatak and its proposed extended area will be in flood risk. Such analysis will help to take

measures at pre, during and post disasters which can decline the risk and assist to build capacity from the

severity of secondary town for ensuring sustainable disaster resilience urban area.

References

Ansary, M. A. and Islam, M. R. (2008) “Microzonation of Sylhet City”, Journal of South Asia Disaster

Studies, Vol. 1, No. 1, pp. 179-195.

Coaffee, J. (2008) “Risk, resilience, and environmentally sustainable cities, Energy Policy”, Vol. 36, Issue

12.

CDMP (2014) District Level Disaster Management Plan Development: District – Sunamganj, Comprehensive

Disaster Management Programme (CDMP II), Dhaka: Ministry of Disaster Management and Relief,

Government of the People’s Republic of Bangladesh.

GoB (2009) The Local Government (Pourashava) Act 2009, Dhaka: Government of the People’s Republic of

Bangladesh.

GoB (2010) Standing Order on Disaster (SOD), Ministry of Food and Disaster Management, Disaster

Management & Relief Division, Disaster Management Bureau, Dhaka: Government of the People’s

Republic of Bangladesh.

GoB (2014) Flood Response Preparedness Plan of Bangladesh, Department of Disaster Management,

Ministry of Disaster Management and Relief, Dhaka: Government of the People’s Republic of

Bangladesh.

Parvin, G. A., Ahsan, S.M.R., and Shar, R. (2013) Urban Risk Reduction Approaches in Bangladesh, Springer

Japan: Kyoto.

RCC (2011) Promoting Use of Disaster Risk Information in Land-use Planning, Regional Consultative

Committee on Disaster Management.

Shaw, R. (2008) “An Overview of Urban Risk of South Asia: Issues, Approaches, and Thoughts”, Journal of

South Asia Disaster Studies, Vol. 1, No. 1, pp. 69-84.

UTIDP (2010) Chhatak Master Plan (2011-2031), Upazila Towns Infrastructure Project (UTIDP), Dhaka:

Local Government and Engineering Department, Government of the People’s Republic of

Bangladesh.

World Bank (2012) Building Urban Resilience: Principles, Tools and Practice, Washington, DC: The World

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ASSESSMENT OF FLOOD RISK OF SECONDARY TOWN IN …€¦ · midterm return flood will affect 26.03% area and short term return flood will affect 22.29% area of the study area. On the