Cynthia Vail Castro

and 1 more

Urbanization and climate change increase water pressure in dams and stress the stability of flood-control structures. Many of the existing dams are aging and have been classified as deficient or having potential for life-threatening hazards in the event of failure. Common mitigation measures include optimizing reservoir release rates and/or implementing additional large—scale infrastructure. Such decisions are typically investigated with drainage models that do not consider co-evolving variables, such as environmental effects or socio-economic impacts. Flood-control reservoirs form complex hydrologic systems that contain numerous interdependencies and intricate feedbacks that must be balanced to achieve optimal resiliency. A spatial multicriteria analysis (SMCA) framework is presented that integrates a suite of social and environmental vulnerabilities with reservoir modeling and decision-making weights. An implementation of adaptive flood control case study of the Addicks and Barker Reservoirs in Houston, Texas, USA during Hurricane Harvey is used to illustrate the proposed technique and to highlight the complexities involved in reservoir decision-making. Hydrologic synergies that would be realized from maintaining status quo operations, optimizing reservoir releases, or increasing storage capacity through engineered solutions are explored. The SMCA methodology is used to visualize how such relationships alter environmental and social vulnerabilities for improved decision-making. In this way, the decision-making process becomes an endogenous component of the integrated human-water-environment feedbacks, thus enabling adaptive management of flood-control reservoirs with comprehensive risk.

Amin Kiaghadi

and 3 more

Understanding the transport of sediments in urban estuaries and their effects on water quality and microorganisms is a convergent challenge that has yet to be addressed especially as a result of natural hazards that affect the hydrodynamics of estuarine systems. This study provides a holistic view of the longitudinal nature and character of sediment in an urban estuary, the Galveston Bay Estuarine System (GBES), under daily and extreme flow regimes and presents the results of water and sediment sampling after Hurricane Harvey. The sediment sampling quantified total suspended sediment (TSS) concentrations, metal concentrations and the diversity of microbial communities. The results revealed the impact of the substantial sediment loads that were transported into the GBES in terms of the sediment grain type, the spatial distribution of trace metals and the diversity of microbial communities. A measurable shift in the percentage of silt relative to historical norms was noted in the GBES after Hurricane Harvey. Not only did sediment metal data confirm this shift and its ensuing impact on metal concentrations; microbial data provided ample evidence of the effect of leaks and spills from wastewater treatment plants, Superfund Sites and industrial runoff on microbial diversity. The research demonstrates the importance of understanding longitudinal sediment transport and deposition in estuarine systems under daily flow regimes, but more critically, following natural hazard events to ensure sustainability and resilience of systems such as the GBES that encounter numerous acute and chronic stresses.