International Dredging Review

International Dredging Review
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Projects to protect and restore bodies of water and to remove and handle contaminated bottom sediments had become a significant part of CLE Engineering’s business so five years ago Susan Nilson started CLE Environmental Inc. an auxiliary company to do the surveying testing monitoring and related permitting involved with these projects. Nilson who had just received a masters degree in environmental engineering had worked for CLE Engineering for five years as a civil engineer prior to going for the advanced degree at the University of Washington Seattle.

Business is lively. Nilson has built up a list of several dozen private and public clients including dredging contractors municipalities construction companies and other private clients.

She offers a valuable service to dredging contractors who bid on environmentally sensitive jobs. She does permit acquisition and amendments recommends cost effective dredging procedures that will best satisfy the permit requirements performs dual frequency surveys to identify bottom sediments and conducts water quality monitoring when the project is underway.

The company is in the midst of a contract to provide permitting dredge consulting and hydrographic surveys for the Hardy Pond a highly visible dredging project in Waltham Massachusetts.

The 45-acre pond once 25 feet deep has been reduced to a few feet by a buildup of weeds and muck attributed to runoff from poorly-planned development in the area as well as fertilizer-contaminated water from previous agricultural activity.

This year the State of Massachusetts allocated $900000 to the project which combined with $300000 from the City of Waltham and about $100000 left over from previous funding is expected to pay for dredging much of the pond.

CLE Environmental was awarded a contract to provide permitting dredge consulting and hydrographic surveying for the project aiding the dredging contractor Mobile Dredging and Pumping of Chester Pennsylvania on permit compliance. She also provided dual frequency hydrographic surveys which showed the differentiation between the suspended sediment and the hard bottom of the pond. For the first phase of the project Nilson provided permitting services turbidity monitoring pre-dredge progress and post-dredge surveys and also identified areas of material migration allowing the city and contractor to locate siltation and modify the dredge areas as needed.

The original specifications had called for mechanical dredging and Nilson advised that this be modified to allow a hydraulic dredge pumping into filter presses eliminating the plan to use Waltham’s baseball field as a dewatering site and reducing the construction impacts.

Mobile Dredging routinely dewaters with belt presses said Lars Garthe project manager. They are using an Ellicott MC 2000 pumping into a holding tank where the slurry is mixed to keep the slurry uniform. A polymer is injected as the slurry enters the belt press and the material emerges as a nearly dry cake which can be trucked away.

The first phase of the project is finished and the second phase about to begin.

Nilson worked with CLE Engineering on the relocation and depression of the Central Artery of Fort Point Channel at Boston Massachusetts. The contract was for the joint venture CPKA (Cashman Perini Kiewit Atkinson) to perform hydrographic surveys develop turbidity control measures and perform water quality monitoring during dredging and construction activities.

Using DGPS and a dual frequency sounder Nilson performed hydrographic surveys to monitor the progress of the dredging. The dual frequency enabled her to analyze conditions and identify fluff and false bottoms.

“Our ability to monitor dredging progress and environmental impacts and to provide rapid results to the contractor and the Department of Environmental Protection (DEP) helped keep the project running and conforming to permit requirements while protecting sensitive downstream users” said Nilson.

A pending project is the New Bedford Superfund site where CLE Environmental will provide water quality monitoring and turbidity expertise. CLE Engineering will perform hydrographic surveys on the project and Nilson will use the data collected on the surveys to calculate volume computations for the project.

CLE Environmental uses a YSI 6000 water quality monitor. Lowered overboard the monitor measures turbidity dissolved oxygen salinity temperature and depth at which the measurement is taken. She has an outfitted aluminum skiff for inland work and has worked on numerous inland and pond restorations that required dual frequency hydrographic surveys and sediment monitoring. Additional equipment and staff is available on a per-job basis.

Susan Nilson is a Registered Professional Engineer in the State of Massachusetts. She received her B.S. in civil engineering from the University of Massachusetts Amherst in 1993 and her M.S. in environmental engineering in 1996. She is the president of CLE Environmental Inc.

CLE Environmental is headquartered in Marion Massachusetts and is a certified women-owned business enterprise (WBE) in Massachusetts and New York.