Assessing Flood Mitigation Strategies Based on Quantification of Risk for Economically Disadvantaged Watershed in Houston
Master of Science
Increase in the frequency of flooding has become a major challenge for many big cities around the world. Policy and decision makers employ both structural and non-structural measures to achieve resilience against flooding, and flood risk maps can be a useful tool for evaluation of both kinds of strategies. Until now, policy makers have mainly been relying on floodplain maps (hazard maps) developed for a given frequency rainfall event (e.g. 100-yr event), which represent only the hydrologic and hydraulic response of the study area for the rainfall event. More information about the consequences of flooding can be presented through spatial risk maps, because they combine the probability of a hydrologic event, the extent of exposure to the event and vulnerability of the exposed area. One city that has been particularly affected by severe flooding in the past and especially within last few years is Houston, Texas. This thesis computes the economic risk for Greens Bayou Watershed located in northeastern Houston for a more comprehensive assessment of flood risk than what is currently done, and to better evaluate the effectiveness of suggested flood mitigation strategies. The computed risk maps depend upon the floodplain maps obtained through the hydrologic and hydraulic modeling. The modeling approach used to obtain the floodplain maps affects the ultimate evaluation of risk. Hence this thesis also compares the risk maps obtained through 1D and 2D hydraulic modeling. Although conducted for only one watershed in Houston, this risk analysis helps us understand the importance of using risk maps for better decision making to mitigate the consequences of flooding in general.
Hydrologic and Hydraulic Modeling; Flood Risk Analysis