PIs and collaborators: Shreeram Inamdar, Joe Galella, Sujay Kaushal

Abstract: Stream and floodplain restoration has been a growing industry in the Mid-Atlantic for the past 20 Years. However, long-term monitoring of restorations is limited, and soil health is rarely a focus. To understand how soil health responds to stream restoration over time, floodplain soil and stream water samples were collected from 15 stream restoration sites (1 to 22 years post-restoration) and two undisturbed reference sites. The majority of restorations followed the principles of Natural Channel Design / Floodplain Reconnection and were located in Maryland and Virginia. Replicate soil samples were collected in restored and unrestored reaches at each site with an assessment of 67 different physical, chemical, and biological soil health metrics. Soil moisture (volumetric water content), organic matter, organic carbon, and undifferentiated phospholipid fatty acids (PLFA) bacteria increased with restoration age, with a maximum for reference sites. Bulk density, soil pH, and percent sand decreased with restoration age at restored sites as well, reaching a minimum value at reference sites. Principal Component Analysis (PCA) revealed distinct clustering of the restored reaches by age categories with a progressive evolution from recently restored to 22 years post-restoration. In contrast, the unrestored reaches were clustered together. This pattern suggests a deterministic shift in the restorations that can be quantified using selected soil health metrics (seven identified here) and which can be extended to assess the recovery of other restorations. Our data also revealed large differences in soil parameters for the reference sites. This suggested that the type and selection of the reference site will have a significant influence on the rate of restoration recovery. Post-restoration monitoring is often mandatory for stream restorations and this research will help guide project design choices and what soil health metrics can best be correlated with restoration goals. A clear shift in soil health metrics post restoration will also allow for restoration agencies to receive water quality credits for the restoration recovery.           

SAMPLED SITES 

Data sets: Online repository LINK

Refereed journal publication - Galella, J.G., Md. Moklesur Rahman, Eric Moore, Marc Peipoch, Jinjun Kan, Alexis M Yaculak, Matthew Sena, Bisesh Joshi, Sujay S Kaushal, and Shreeram Inamdar. (2025). Soil Health Metrics for Assessment of Floodplain Restorations. Environmental Research Letters, 20 084010. LINK