Comparison of stormwater dynamics and storage capacity among urban prairies of varying ecological quality

Climate change is leading to more extreme precipitation events in the Midwest, which require new ways of managing stormwater, particularly in urban areas. Green infrastructure has become an increasingly popular way of providing additional stormwater storage, as well as supporting urban biodiversity. However, we dont yet understand the inter-relationships between the ecological quality of urban green spaces and the stormwater storage that they can provide. Indian Boundary Prairies (IBP) is a prairie-wetland complex located in Markham, Illinois, south of Chicago. The impact of urbanization varies across the five prairies in the IBP complex. Gensburg-Markham Prairie (GMP) is a high-quality prairie that was never developed. A kilometer northwest of GMP, Paintbrush and Sundrop Prairies experienced more extensive plowing and on-site development leading to degradation of these areas. Consequently, GMP provides high quality habitat and supports rich biodiversity across its 40-hectares whereas Paintbrush and Sundrop Prairies display more internal heterogeneity in habitat and ecosystem quality. We installed a network of water level and electrical conductivity sensors at GMP in 2016 and at Sundrop and Paintbrush Prairies in 2020. High-frequency data collected by these sensors provides key information on the hydrologic response of each prairie, including stormwater storage. We compared results from all three prairies to assess anthropogenic impact, revealing greater heterogeneity in the hydrogeological characteristics, internal hydrological dynamics, and stormwater response in the more degraded prairies, Sundrop and Paintbrush, relative to GMP. Developing a better understanding of how the ecological quality of urban prairies impacts their hydrology and water storage capacity can inform restoration efforts and the design and maintenance of green infrastructure. As green infrastructure becomes increasingly relied upon as a means of stormwater management, understanding how the quality of urban green spaces impacts storage capacity is critical for the maintenance of these spaces and the services they provide.