Eastchester Creek Channel Maintenance Dredging

CASHMAN DREDGING was contracted to conduct maintenance dredging of the Eastchester Creek (also known as the Hutchinson River) navigational channel. Prior to performing maintenance dredging between the overhead gas line and the Fulton Avenue Bridge, CASHMAN noted that the deteriorated bulkhead along the west side of this portion of the Creek could possibly be undermined during dredging and result in a failure of the bulkhead. We also notified the Army Corps that the existing width of the waterway (~75 feet wide) in this area was less than the 90 feet shown on the contract drawings. To alleviate these issues, the Contract was modified in this portion of the channel to less than full width to prevent possible bulkhead failure and to perform dredging with the scow overlapping the starboard half of the dredge bow. CASHMAN completed this complex and difficult dredge project within the contract performance period. 


PROJECT HIGHLIGHTS 

• CASHMAN removed ~25,000 yd³ of material utilizing a CAT- 375 excavator mounted on Flexifloat barge system. 
• A 5-yd³ TGS environmental hydraulic clamshell bucket was used to load maintenance material into hopper barges. 
• Material was dredged to a project grade of -8 feet with an over depth of -1 foot. 
• Loader hopper barges were dewatered into a decanting barge using a 6-inch Godwin hydraulic pump. 
• Hopper barges were moved to an offloading and processing facility with ultimate disposal at a permitted landfill site. 
• This project was not a typical project; the channel was very narrow and shallow: 
  • Work was performed during high tidal periods in order to achieve economical barge loads. 
  • Dredging was frequently stopped and equipment temporary relocated to allow vessel passage through the channel. CASHMAN frequently coordinated with the local authority to open the bridges to allow tugs and scows to pass through.