Restoration of the Turning Basin and tidal wetlands at Saugus Iron Works National Historic Site: Final report for 2008-2012 monitoring.

James-Pirri, Mary-Jane; Nelson, Sarah; Vaux, Peter

The final report for Saugus Iron Works National Historic Site (SAIR), a small, urban park located just outside of Boston, MA, preserves the site of America’s first sustained, integrated, and successful iron works. The primary natural resources of the park are the tidally influenced turning basin and Saugus River, tidal wetlands bordering the river, and riparian woodlands. This Natural Resource Condition Assessment was organized by ecosystem resource, then grouped by the riverine-wetland environment and the terrestrial environment. Within each grouping, the natural resources were described, the condition and trend were evaluated based on selected metrics, and data gaps and threats were highlighted. The overall quality of the smelt spawning habitat in the park rated in the lower 50th percentile when compared to other Massachusetts rivers. The aquatic benthic macroinvertebrate community was dominated by pollution-tolerant fauna and the community rated as very poor by the Hilsenhoff Biotic Index. The majority of the water quality (e.g., dissolved oxygen, nutrients, organic enrichment, pathogens, salt inputs, thermal modifications) parameters for the Saugus River at SAIR were impaired, with only pH and heavy metal concentrations meeting water quality standards. Recent analyses of riverbed sediments indicate that even though contaminants were present in the riverbed sediments, they were all below probable effect concentrations and were lower than observed prior to the restoration. The restoration of the turning basin waterfront and wetland likely removed the vast majority of contaminated wetland sediments. River discharge flow rates can be below recommended minimum flow rates, especially during the late spring. The upland natural vegetation is limited to the narrow riparian woodlands along the eastern shore of the Saugus River. This mixed successional forest was co-dominated by invasive plants, most notably in the understory; however, the park has made substantial progress in reducing the abundance and distribution of invasive vegetation. The forest breeding bird community has consistently been rated as significant concern by the Northeast Temperate Network (NETN) guild rating system, with a lower-than-desired number of species in guilds representative of high-integrity ecological condition and a higher-than-desired number of generalist species considered indicative of low-integrity ecological condition. The number of waterbirds using the wetlands and tidal flats has increased since the restoration. Air quality of the park reflected the larger regional air quality of New England with total nitrogen wet deposition, total sulfur wet deposition, ozone, and visibility all exceeding acceptable values for air quality.

Restoration of the Turning Basin and tidal wetlands at Saugus Iron Works National Historic Site: Final report for 2008-2012 monitoring.

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