Modeling Flood Stage-Duration-Frequency: A Risk Assessment of Critical Infrastructure in the Tidal Potomac

The service of a critical infrastructure, such as a municipal wastewater treatment plant (MWWTP), is taken for granted until a flood or another low frequency, high consequence crisis brings its fragility to attention. The unique aspects of the MWWTP call for a method to quantify the flood stage-duration-frequency relationship. By developing a bivariate joint distribution model of flood stage and duration, this study adds a second dimension, time, into flood risk studies. A new parameter, inter-event time, is developed to further illustrate the effect of event separation on the frequency assessment. The method is tested on riverine, estuary and tidal sites in the Mid-Atlantic region. Equipment damage functions are characterized by linear and step damage models. The Expected Annual Damage (EAD) of the underground equipment is further estimated by the parametric joint distribution model, which is a function of both flood stage and duration, demonstrating the application of the bivariate model in risk assessment. Flood likelihood may alter due to climate change. A sensitivity analysis method is developed to assess future flood risk by estimating flood frequency under conditions of higher sea level and stream flow response to increased precipitation intensity. Scenarios based on steady and unsteady flow analysis are generated for current climate, future climate within this century, and future climate beyond this century, consistent with the WWTP planning horizons. The spatial extent of flood risk is visualized by inundation mapping and GIS-Assisted Risk Register (GARR). This research will help the stakeholders of the critical infrastructure be aware of the flood risk, vulnerability, and the inherent uncertainty.

Feasibility of An Online Survey Examining the Physical Activity Patterns Among South Asian Adults Residing In the United States

Background: Physical inactivity is a major risk factor for cardiovascular disease and diabetes among South Asians (SAs) - Bangladeshi, Bhutanese, Indian, Maldivian, Nepali, Pakistani, and Sri Lankan. Methods: An online survey was used to determine the feasibility of examining physical activity (PA) levels of SAs living in the US. The Social Ecological Model was the theoretical basis for identifying individual-level, social environmental, and physical environmental factors that impact PA. Results: Ethnicity, intention, self-efficacy, and perceived health benefits of PA were significantly associated with being physically active. Facilitators to PA included achieving improved health; while barriers were lack of time to exercise, unfamiliarity with PA, and nonexistent gender-specific PA facilities. Conclusions: This study showed that online surveys can be a promising tool for data collection among SAs. Health promotion programs should include education on the benefits of PA, and provide culturally sensitive facilities that support PA, especially for SA women.