WATERSHED RESPONSE TO 18-20TH CENTURY AGRICULTURAL PRACTICES IN UPLAND RIVER CORRIDORS IN SOUTHERN NEW ENGLAND

Sediment cores collected within river corridors can be used to reconstruct past environmental changes in the contributing watershed and determine sedimentation rates to better understand the role of climatic variation, storm events, and anthropogenic activity. Soil erosion and sedimentation rates have increased globally from anthropogenic land use, resulting in the formation of legacy sediment deposits in river corridors around the world. The northeast region of the US has a well-documented 300+ year history of land use changes following European settlement, initiated with widespread 18-19^th century deforestation primarily for agricultural purposes, followed by late 19^th-early 20^th century abandonment and reforestation. However, although this deforestation and intensive agricultural activity is well established in the region, previous studies have suggested lower soil erosion and quantities of legacy sediment stored in New England compared to other areas of the U.S. that experienced similar timing and intensity of land use (e.g. Johnson et al., 2019; Dow and Ouimet, 2022). In this study, we synthesize a regional dataset of sediment core studies for southern New England to quantify anthropogenic sedimentation in depositional environments and the extent of land clearance to address the response of watersheds to the magnitude and type (agriculture, logging) of historic land use. We combine 19^th and 20^th century sedimentation records from >30 wetlands, lakes, and reservoir cores with LiDAR-derived stone wall maps and spatial analyses using watershed characteristics such as extent of cleared land, land use type, and slope to evaluate this response. Stone walls remain as a clear legacy of past agricultural practices, are visible in LiDAR, and can serve as a proxy for peak land clearance for agriculture ca. 1850. Preliminary results suggest that sedimentation related to anthropogenic activity in watersheds is highly variable, and the extent of land clearance may not solely explain discrepancies in sedimentation.