Abstract

Drumlins are glacially derived landforms that are prominent in the landscape over much of southern New England. We carried out a comprehensive ground-based survey in a three-town study area in eastern Massachusetts with the goals of establishing the extent to drumlins have been altered and assessing the associated environmental consequences and probable driving factors. Results show that many drumlins have been significantly altered through levelling and truncation (creation of steep cut and fill slopes), with projects involving movement of 1−1.5×106 m3 of earth materials not now uncommon. Stormwater and wetlands infractions were documented at all the larger excavation sites and resulted in enforcement actions and fines in many cases; the broader environmental consequences of the loss/alteration of these forested uplands are harder to establish. The excavations are significant in terms of materials cycling: the movement of earth materials, when considered regionally, greatly exceeds natural denudation processes and is also greater than during other periods of high anthropogenic denudation. Our findings suggest that the region’s glacial landscapes are at risk given current development patterns. The accelerating rate of land-surface change is undoubtedly also generalizable to other fast-developing regions of the United States. The landform alterations documented are part of a changing pattern of land use and vegetation cover since the Colonial era and are linked to shortages of land for development, current development and building practices, and lack of explicit rationales for preservation of the region’s geoheritage.

Highlights

  • The drumlins of southern New England originated during the Wisconsinan (10,000–110,000 BP) and Illinoian (130,000– 300,000 BP) glacial stages when they formed beneath massive ice sheets during the process of ablation [1,2]

  • Examples of drumlins being significantly altered in eastern Massachusetts motivated us to investigate this phenomenon and attempt to establish a context in which the significance of landform alterations could be assessed

  • One analysis we undertook showed that the excavations are extensive enough to be detected using remotely sensed data [4]. In conjunction with this analysis we carried out a ground-based survey of drumlins in a three-town study area, the results of which are presented here

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Summary

Introduction

The drumlins of southern New England originated during the Wisconsinan (10,000–110,000 BP) and Illinoian (130,000– 300,000 BP) glacial stages when they formed beneath massive ice sheets during the process of ablation [1,2]. The drumlins characteristic of this landscape are hills that are typically 15–30 m high and tear-drop shaped, tend to occur in groups or swarms, and can range in composition from till, stratified diamicton, and bedrock to fluvially derived materials [3]. Their formation appears to be a complex function of erosional, depositional, and deformational processes occurring when the ice sheets moved across permanently frozen ground near the ice margin [3]. We document examples of the former, including wetland siltation, stormwater discharge into streams and water bodies, and slope failures stemming from the excavations

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