Land cover and climate changes, attributed to natural and anthropogenic forcings, cause deviations in geomorphic processes that act to deliver sediment from watersheds to lakes. In New England, contradictory evidence exists as to the influence of deforestation associated with EuroAmerican settlement and major flood events on watershed erosion rates over the past ~250 years. Through combining sediment core analysis from Ossipee Lake, New Hampshire with geomorphic analysis of the Ossipee Lake watershed, this study quantifies Holocene through Anthropocene watershed erosion rates, and assesses variations in rates in relation to short-term historic events such as major storm events or deforestation, and long-term variations related to natural climate variability and postglacial landscape evolution. An 8.63 m core was collected and spans the entire period from deglaciation to present. Bulk composition and age-depth modeling, utilizing both short-lived radioisotopes and radiocarbon dating, are used to quantify changes in deposition and inferred erosion rates over time. Additional insight on sedimentary processes is provided by measurements of magnetic susceptibility and bulk geochemistry. Lake-sediment data suggests clastic sediment mass accumulation rates vary between 0.0032 to 0.5870 g/cm 2 /yr, with deposits of increased terrestrially derived sediment focused between ~8500 to 7800, ~6500 to 2500, and 1600 cal yr BP to present. Geomorphic analysis is used to identify regions within the watershed that act to deliver sediment to Ossipee Lake. Potential sources of sediment supply include loose, unconsolidated proglacial deposits near Ossipee Lake that transition to primarily till in upland areas. Calculated bed shear stress along rivers highlights areas in the watershed capable of transporting sediment and areas that can serve as traps thus limiting sediment delivery to Ossipee Lake. iv ACKNOWLEDGMENTS I would like to thank Noah Snyder for his guidance, assistance, and insight to this project in addition to my academic experiences as a graduate student. Thank you to Timothy Cook who is one of the people who sparked my research interest in Earth Surface processes and lakes during my undergraduate studies and research, and who has also provided guidance and assistance in this project. Thank you to Jeremy Shakun and Tara Pisani Gareau for serving as committee members. Thank you for my lab group at Boston College and Worcester State University for contributing to field work and research collaboration:

Continuous records of sediment yield spanning from the late glacial through the Holocene to the present day provide an important opportunity to investigate landscape evolution over various timescales in response to a variety of natural and anthropogenic forcing mechanisms. This study investigates variations in sediment yield and landscape evolution in the 768 km2 watershed of Ossipee Lake, New Hampshire, USA. We pair subbottom sonar observations with analyses of lacustrine sediment cores to interpret a 12,000+ yr record of lake sedimentation in terms of changes in sediment yield and landscape evolution. Our results indicate high rates of sediment redistribution following deglaciation at ~14,500 to ~12,000 cal yr BP, followed by a period of gradually decreasing sediment yield until ~9000 cal yr BP, marking the termination of the most intense period of paraglacial landscape adjustment. From 9000 cal yr BP to 1850 CE, sediment yield is highly variable and reveals a slightly increasing trend that we attribute to a dominant hydroclimatic control on erosion driven by increasing effective precipitation in the region throughout the Holocene. Despite evidence for a highly dynamic landscape and an abundance of unconsolidated glacigenic surface deposits throughout the watershed, we interpret a modest erosional impact from anthropogenic land use.

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Temperature in degrees Fahrenheit (°F) may be converted to degrees Celsius (°C) as follows: °C = (°F -32) / 1.8. vii DatumsVertical coordinate information is referenced to the North American Vertical Datum of 1988 (NAVD 88).Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83).Elevation, as used in this report, refers to distance above the vertical datum. Supplemental InformationA water year is the 12-month period beginning October 1 and ending September 30. It is designated by the calendar year in which it ends.Normal, as used in this report, approximates the statistical average or norm.