Abstract:
Stonn water flood hazard due to inadequate drain is a major concern in the Paurashavas in
the Chittagong Hill Tracts (CHT). To address the issue of urban storm flood hazard,
drainage master plans have been prepared for the three Paurasbavas in the CHT nnder the
Urban Governance and Infrastructure Improvement Project (UGIIP) ofl..ocal Government
Engineering Department (LGED). The plan would be implemented over a period of 10
years. The availahle fund for drain construction in each year is a fraction of the total
requirement. Therefore, a method for prioritization of drain construction in the
intermediate years is needed. Development of Multi Criteria framework for prioritization
of storm drain works is the ultimale goal of this research. This research has been carried
out by selecting Bandarban Paurashava as the study area.
A questionnaire survey has been carried out to assess public response on stonn water flood
hazard. The survey has covered 190 households which was obtained on the basis of
statistical sampling formula. The distribution of J 90 households among 9 Wards is in the
proportion 10 Ward population. The purpose of the survey is 10 assess flood situation and
its consequences. The respondents identified location of flood affected area, causes of
stonn water flood and public life disruption due to storm water flood.
Area-elevation relationship has been developed based on the contour map of the study
area. Volume-elevation relationship has been derived from the area-elevation relation. A
rainfall depth of 123 mm has been used to estimate runoff volume. Based on runoff
volume, flooded area has been identified using volume-elevation and area-elevation
relationships. Besides flooding, nmoff ways along hill slope areas make disruption to the
public and private properties. The runoff ways along hill slope areas have been identified
based on contour map.
A total of 17.8 kID of new drains have been proposed in the Master Plan for Bandarban
Paurashava. The new drains consist of 78 independent drains. Five criteria have b<;en
selected to represent storm flood hazard that would serve as the basis for prioritization of
drain construction. These criteria are drain deficiency, flood magnitude, population
suffcring, damage characteristics and social vulnerability. Magnitude of five criteria have
xlii
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been calculated for every drain. Standardized value of each criteria arc added for a drain to
get total score for the drain with the help of Linear Additive Model. The scores of 78
drains are ranked in order of decreasing magnitude, and the rank represents priority order.
The scrics of 78 ranks is to be divided into 10 segments to set the year-wise
implementation sehedule of78 drains over 10 years. The segments are to be such that the
total drains in a segment ean be implemented using the budget for that year.
