The selected contractor used geotubes to dewater the sediments, excavating and hauling the sediment from the geotubes to an offsite reuse location. Therefore, GZA designed a hydraulic dredging program that minimized impacts of turbidity to endangered species downstream by requiring a mechanical sediment dewatering program sited upland to the pond.

This conventional dredging method negatively impacted a habitat area to several rare and endangered species downstream of the pond. Past dredging efforts had involved draining the pond and using excavation machinery, which caused significant sediment deposition downstream of the pond due to the difficulty of controlling mobilization of sediment once the pond drain was re-opened. GZA provided design, permitting, and construction phase services to Smith College including hydraulic dredging of Paradise Pond, which is continuously subject to sedimentation and relatively rapid re-accumulation of sediments as an impoundment of the Mill River.

GZA was initially engaged by Smith College in 2004 to address immediate concerns and retained in 2015 to address long-term solutions and provide more comprehensive management. Frequent flash flooding on this high-energy river causes mobilization of naturally-generated sediments, and some degree of sediment removal must be conducted every seven to 10 years to maintain the historic open water area of Paradise Pond, located on the campus of Smith College. The Mill River watershed leading to Paradise Pond comprises 54 square miles of steep, mostly undeveloped and wooded terrain in the foothills of the Berkshire Mountains.

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