EAR-PF: Green infrastructure scaling from local observations to regional applications as a coupled human-water system

Dr. Cyndi V. Castro has been granted an NSF EAR Postdoctoral Fellowship to study issues of scale regarding nature-based solutions (NBSs) at the University of Illinois Urbana-Champaign with mentoring from Professor Murugesu Sivapalan.

Traditionally, stormwater is dealt with through grey infrastructure, which rapidly transports rainfall offsite. NBSs, on the other hand, use natural materials to slow stormwater flow through onsite retention. As rainfall conditions intensify, integrated NBSs become necessary throughout the urban framework to alleviate overburdened drainage networks.

NBSs have shown great promise in site-specific applications, however, widespread use of such technology has not occurred due to a lack of catchment-scale relationships. The efficacy of NBS solutions is a complex function of local conditions (i.e., rainfall, flow travel times, land characteristics) that are not well understood. The need to characterize scale relationships includes interactions between NBS systems and society.

Anthropogenic effects on catchments alter the hydrologic response and are an important component in coupled human-water systems. This study aims to better understand the influence and scalability of hydrological and social phenomena in urban watersheds to fill an important knowledge gap and to improve widespread implementation of NBS solutions. The work has broad implications for the use of NBSs in urban settings and will work to involve the youth of Houston, Texas, in the proposed research.

The project also includes plans to improve infrastructure for NBS in economically disadvantaged neighborhoods and will engage with a wide variety of stakeholders who deal with flooding and stormwater.

Dr. Castro proposes to investigate the scaling laws associated with NBSs by combining traditional top-down and bottom-up modeling approaches. Dr.

Castro will engage with various global climate adaptation leaders through an established academic-governmental partnership to better understand the governing societal influences associated with NBS processes. She will identify governing physical processes through data-driven computational modeling and similarity analyses, including spatial characteristics (watershed properties) and temporal variability (rainfall duration, time of concentration).

A top-down approach will be conducted to understand the macro-scale governing processes through the use of bucket models. The process controls on the overall water balance will be extracted from long-term rainfall-runoff signatures and coarse-grained over decreasing scales. Finally, Dr.

Castro will investigate the shared behaviors between the bottom-up deterministic models and the top-down bucket models, elucidating where the two approaches overlap, thereby linking NBS processes across scales. By identifying common social and hydrologic factors that are scalable, Dr. Castro seeks a novel description of NBS processes for improved planning across spatial and temporal domains.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.