Environmental Dredging Project
February
27,
2018
Location: Northeast River
Project Overview: Contain hydraulic dredge site contaminated sediments within several work zones utilizing 3,400’ of double-walled TYPE 3 HD curtains to manage site turbidity.
ABASCO Contribution: Turbidity curtain design: manufacture and installation support
- Type 3 HD with 7’, 10’ and 14’ depths using furling lines
- Dual 5/16” SS top tension cables & 3/8” HG Ballast Chain
- 22oz PVC coated fabric and 1’ & 4’ windows with 12 oz/yd non-woven polypropylene with 100 US sieve flowing 75 gpm/ft2
- Aluminum ASTM Universal Slide connectors with anchor points and ASTM Toggle pins
- 50’ and 100’ sections using SS grommets at vertical ends with furling lines
- AS 22 Anchor packages with Danforth anchor, chain leader, ½” poly rope, A-2 Anchor Buoy
- TB-18 Tow Bridles
- Lighted Buoys
Project Challenges and Features –
- Monitored NTU Release: 5 NTU Delta, must remain within 95%
- Strong winds: 30 – 40 mph
- Sizable tidal exchange and winter storm surge
- Strong currents during storms projected and bridge crossing currents
- Two Nor’easter Storms
- Dredge activity limited by herring and shellfish migration; fish corridors
- Project duration exceeded one year
- Filter window flow arrangement for tidal, rain and storm events
