Tide gate modulation of wetland function: decision support through engineering best practices

Northeastern University, Boston MA

Investigators

Abstract

1702618 (Patterson). Tide gates are valves that are designed to protect life and property but often negatively affect wetlands. This research aims to develop best practices for their operation to maximize protection of people and ecosystem health. In the US, thousands of tide gates are maintained and operated by municipalities and conservation boards. How tide gates are operated affects risks of flooding and fire, and wetlands health, in competing ways. This project will develop new decision support tools for tide gate management using coupled models of water exchange, sediment movement and pollutant loading based on the EPA model QUAL2K, and objective functions for ecosystem services, water quality, and flood and fire risk. By coupling measurements and modeling, this research will move tide gate design and management well beyond prior understanding. Methodology includes advanced microbial sensors for nitrate, passive contaminant samplers for toxins, and autonomous sensors and vehicles. In cooperation with municipalities in Massachusetts, and a diverse range of stakeholders, tide gate function will be investigated in a large urban coastal marsh with a history of toxin exposure, a smaller urban marsh used recreationally, and a 'pristine' marsh. Decision support tools for tide gate operators will provide directed advice on when and how much to open tide gates under various scenarios, improving public safety and ecosystem health of critical wetlands. Two undergraduates working on 6 month co-ops, and a graduate student, will be trained. Online visualization of tide gate state, water chemistry, biota, and toxins at a dedicated web site will be used to educate managers, the public, and K12 programs. Workshops during years 2-3 will engage the user community during the development of the decision support tools. Public policy MS students will participate in capstone projects to investigate the overlap in regulations among federal, state and local entities to facilitate implementation of best practices, while Civil Engineering undergrads will be involved in required capstone projects and will look for opportunities for both groups to collaborate. This research potentially will increase the sustainability, resilience, and anti-fragility of coastal communities because existing tide gates will be better managed, reducing risk of fire and flooding (and toxin dispersal for some sites), while increasing ecosystem services like essential fish habitat and storm