Using a cost-to-benefit index (CBI) to set priorities for a city master plan drainage system

ABSTRACT

In urbanized areas, where development is essentially uniform with respect to drainage to streets, the flood damage potential may be related to the flood depth in the adjacent street section. For a particular street geometric cross-section, a given flood depth may be correlated to different levels of flood damage potential depending upon the development of contiguous land areas. The Cost-to-Benefit-Index (CBI) method is a graphical means to communicate important information regarding master planning prioritization of flood control system elements targeted for improvement. Using the CBI approach, decisions can be made regarding which system reach or system elements may be ranked as having the highest priority in scheduling construction. Additionally, a CBI map aids in communicating to the public the relative importance of any particular element with respect to the overall master plan