Lu Liu

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I teach CE 3880 Sustainable Engineering & International Development, CE 3720 Engineering Hydrology and Hydraulics, CE 5740X Integrated Assessment Modeling and Science-Policy Integration for Global Environmental Change. I am also a committee member of Fobes-Ronald Lecture Series.

Highlighted Projects:

1. Collaborative Research: Assessing climate resilience of combined sewer systems and its impact on marginalized communities
   1. Many U.S. cities experience combined sewer overflows (CSO) during wet weather that result in negative environmental and health consequences. Of particular concerns are marginalized communities residing historically in flood-prone zones, facing heightened susceptibility to CSO impacts. Current urban wastewater systems were designed to withstand peak flows derived from outdated precipitation records. With more frequent and intensified occurrences of wet weather events exacerbated by climate change, cities are confronted with urgent challenges to effectively manage and mitigate CSOs in an equitable manner. In this project, we aim to analyze the resilience of combined sewer systems in response to climate change and assess potential CSO exposures and impacts on marginalized communities. We developed a novel integrated modeling framework and coupled with qualitative-quantitative survey method to perform relevant, local phenomena-based research. This project will 1) advance data analytics and modeling methodologies for urban wastewater systems; 2) assess system-level resilience of the test-bed system (e.g., Des Moines, IA) to wet weather conditions under the influence of climate change; and 3) uncover the vulnerability of marginalized communities to future likely CSO incidents.

2. Eco-Hydrological Modeling for Sustainable Drinking Water Protection in the Des Moines River Basin
   1. Nitrate contamination in the Des Moines River Basin (DMRB) threatens public health, with drinking water sources frequently exceeding the EPA’s nitrate concentration limits. Agricultural practices such as fertilizer and manure applications are significant contributors to this impairment, intensified by widespread subsurface tile drainage and more variable rainfall from climate change. Hypoxia in the Gulf of Mexico, a direct consequence of nutrient loading from the Mississippi River, with the Des Moines River being the most significant contributor within tributaries, continues to expand. Addressing this legacy issue requires spatially targeted best management practices (BMPs) informed by high-resolution modeling. In this research, we developed a forecast-based decision support framework to evaluate the impact of agricultural land use, tile drainage, and BMPs on nitrate transport under future climate scenarios. We integrated the SWAT+ ecohydrological model with the high-resolution Tile and Rotation Enhanced Cropland (TREC) dataset and climate projections from CMIP6 to simulate nitrate dynamics from 1990 to 2099 across the Des Moines River Basin. The model identifies nutrient hotspots and quantifies nitrate load reductions under various climate and socio-economic scenarios, enabling comparison of upstream interventions with downstream treatment strategies. Our results support data-driven planning for watershed-scale nutrient reduction and long-term drinking water safety in DMRB and its downstream reaches.

3. Evaluating Climate Change Resilience and Adaptation Initiatives and Programs
   1. Climate change presents one of the most significant challenges organizations and communities have ever faced. Adaptation strategies and programs have been implemented across the country to protect properties and communities and strengthen their resilience against future disastrous weather events. Despite the broad adoption of various adaptation initiatives, the effectiveness and cost-benefit of these programs remain to be tested over time. Understanding how exactly an adaptation enhances property resilience will be critical for entities such as insurance companies in developing more reflective underwriting or pricing credit criteria. The objective of this research is to produce a roadmap for actuaries and underwriters to help determine how much credit should be given to various levels of resilience. The roadmap will enable users to parse out the anticipated cost savings and reduction in risk by source of loss (e.g., differentiating between insured and uninsured losses, direct damage to property versus indirect economic losses, etc.). This roadmap will serve as a foundational tool for advancing the evaluation of climate resilience and adaptation initiatives.

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For more information on Dr. Lu Liu’s research, teaching and outreach activities, please visit The Liu Group: Human-Environmental Systems Research.

Publications

For a full list of Dr. Liu’s publications, please visit her Google Scholar.

Selected publications:

[1] Liu, L.; Zhou, X.; Dueñas-Osorio, L.; Stadler, L.; Li, Q. Hybrid wastewater treatment and reuse enhances urban water system resilience to disruptive incidents. Nature Water. 2023. https://doi.org/10.1038/s44221-023-00166-6.

[2] Liu, L.; Lopez, E.; Dueñas-Osorio, L.; Stadler, L.; Xie, Y.; Alvarez, P. J. J.; Li, Q. The Importance of System Configuration for Distributed Direct Potable Water Reuse. Nat. Sustain. 2020. https://doi.org/10.1038/s41893-020-0518-5.

[3] Liu, L.; Hejazi, M.; Iyer, G.; Forman, B. A. Implications of Water Constraints on Electricity Capacity Expansion in the United States. Nat. Sustain. 2019, 2 (3), 206–213. https://doi.org/10.1038/s41893-019-0235-0.

[4] Liu, L.; Hejazi, M.; Li, H.; Forman, B.; Zhang, X. Vulnerability of US Thermoelectric Power Generation to Climate Change When Incorporating State-Level Environmental Regulations. Nat. Energy 2017, 2, 17109. https://doi.org/10.1038/nenergy.2017.109.

Primary Strategic Research Area

Resilient Infrastructures

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