Browsing by Author "Juan, Andrew"

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    Developing a Radar-based Flood Alert System For Sugar Land, Texas
    (2011) Juan, Andrew; Bedient, Philip B.
    This thesis presents a framework for a radar-based flood alert system (FAS) for the Oyster Creek Watershed to aid the City of Sugar Land in flood forecasting. The motivation for using this particular system stems from a radar's ability to provide flood warning lead-time when calibrated with available gauge information. This study follows a typical workflow in analyzing watersheds, which involves converting excess rainfall to runoff, then converting the resulting flow rates to polygons that show water levels. This thesis also introduces the Flood Warning Indicator (FWI) as a component of Sugar Land's FAS. FWI only uses radar rainfall to portray potential flooding problems within the watershed through GIS mapping, which is helpful when gauge information is unavailable. Having a significant role in the communication of flood information, FWI may be applied in other areas that lack the resources to build extensive gauge networks for flood monitoring and radar calibration.
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    Evaluating the Hydrodynamic Performance of Green and Gray Infrastructure in Urban Watersheds for the Greater Houston Region
    (2016-08-11) Juan, Andrew; Bedient, Philip
    Flooding is the costliest hazard in the United States. Among the many flood prone areas in the nation, the Greater Houston Region is considered one of the most vulnerable, due to high intensity rainfall, flat topography, high imperviousness, and poor infiltration. Traditionally, Houston’s flood control strategy involves the implementation of gray infrastructure (e.g., channelization and detention basins). However, even after spending billions of dollars on numerous flood reduction projects, Houston continues to suffer from flood damages. Houston’s severe flooding issue has prompted various efforts to develop new flood control strategies. One alternative is Green Infrastructure, or Low Impact Development (LID), which consists of land development strategies aiming to preserve predevelopment hydrology. Originally designed to improve water quality, LID has also been shown to attenuate flood flows. Despite its popularity in the Northeast and the Northwest, the flood reduction benefits of LID in the Greater Houston Region are poorly understood. Moreover, most currently available models capable of simulating site-scale LID features are applied to small-scale study areas, providing limited insight at the watershed-scale. To bridge these knowledge gaps, this research proposes a method to model two site-scale LID features: green roofs and rain gardens at the watershed level. The hydrologic performance of an experimental watershed-wide LID implementation at The Woodlands is evaluated using a distributed hydrologic model. The findings suggest that LID features can be used able to reduce peak flow and runoff volume for smaller magnitude and intensity storms, but has limited effects for larger, more intense events. For comparison, this research also examines the hydrodynamic performance of gray infrastructure at two different scales of implementation: a catchment-wide flood reduction project at Brays Bayou and a local drainage improvement at Harris Gully. Due to the difference in application scales, floodplain analyses of both studies reveal varying degrees of flood reduction benefits. By understanding the flood reduction potential and limitations of green and gray infrastructure, this research can help floodplain managers and local stakeholders in the proper selection of flood control strategies.
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    Integrating Reservoir Operations and Flood Modeling with HEC-RAS 2D
    (MDPI, 2020) Garcia, Matthew; Juan, Andrew; Bedient, Philip
    Current free to use models developed by the United States Army Corps of Engineers (USACE) perform unique functions (e.g., hydrology, hydraulics, reservoir operations, and flood impact analysis) that are widely used in numerous studies and applications. These models are commonly set up in a framework that is limited to point source connections, which is problematic in regions with flat topography and complex hydrodynamics. The separate models need to be integrally linked and jointly considered for accurate risk communication and decision-making, especially during major storm events. Recently, Hurricane Harvey (2017) exposed the shortcomings of the existing framework in West Harris County, TX, where an insufficient understanding of potential flood risk and impacts contributed to the extensive flood damages sustained in the region. This work illustrates the possibility of using a single hydraulic model, HEC-RAS 2D, to perform all hydrologic, hydraulic, and reservoir operations modeling necessary for accurate flood impact assessments. Implications of this study include a simplification of the entire flood impact analysis, which could help future flood risk communication and emergency planning.