The Dredge Report | Week of May 23, 2021
Sand Shifter – Allen Harbor Channel, Harwich
The dredge Sand Shifter, the pushboat Stephen S. Bradbury, and 5,000′ of pipe were moved from Aunt Lydia’s Cove, Chatham to Harwich on Thursday with the assistance of Chatham’s Harbormaster Stuart Smith and Harwich Harbormaster John Rendon of Harwich to get setup for the next project in the Allen Harbor Channel. Their assistance in the moving pipe to and from Aunt Lydia’s Cove was invaluable and greatly appreciated as the navigation in this area requires a great deal of local knowledge in order to minimize the transit time and avoid any problems.
Setup was completed on Friday with dredging planned to start on Tuesday after the Memorial Day holiday weekend.
The target volume for the Allen Harbor Channel is 10,913 Cubic Yards with several disposal sites at private beaches located east and west of Allen Harbor in addition to Grey Neck beach.
Project Recaps: Popponesset Bay Approach Channel
There hasn’t been much spare time to review the outcomes of many of our projects over these past months so from time to time I’ll take the opportunity on providing a summary of some of the most recent ones. First on the list is the Popponesset Bay Approach Channel project.
The project required the removal of 9,993 Cubic Yards of material by the Cod Fish II. The disposal area for this project was the southwestern end of the spit and adjacent areas.
With a pumping distance 6,600 feet to the disposal area, the County used the converted dredge Cod Fish I as the Booster Station.
The project was staged and ready on March 27th but due to adverse wind and wave conditions dredging was not started until April 2nd and it continued through April 27th. Wind and seas caused delays on and off throughout this period in addition to one mechanical breakdown.
As the project started after April 1st, a Time of Year (TOY) restriction for Piping Plovers was in place requiring a waiver and Piping Plover observers to be on site throughout the dredging period.
Both cross-over sections of the pipe had to be removed from the outer spit on April 17th, and the dredging output was moved to another area part way down the spit. A dredging extension granted to April 26th was extended through April 28th and the pipe was removed on April 29th.
- The retrofitted dredge Cod Fish I was used as the Booster Station increasing the production rate and allowing the pumping distance of 6,600 feet to be achieved.
- A breakdown occurred on April 6th on the clutch mechanism (PTO) on the Cod Fish II. The County’s second dredge, the Sand Shifter was moved from Stage Harbor, Chatham on April 7th, and continued dredging from the 8th through the 10th.
- The repairs were completed on the Cod Fish II on April 10th, and the Cod Fish II resumed dredging on April 12th .
- Final volume removed was 9,999 Cubic Yards.
The following table details the number of days for each operation. There were a total of 21 working days to complete this project as we experienced weather, mechanical and environmental delays throughout the project period.
If we compare the County dredge costs to the private sector1, this same project would cost the Town of Mashpee an estimated $799,920 as compared to the County fee of $129,987.
1 Private sector costs were obtained by a review of dredging contractors in 2020 by Foth Infrastructure & Environmental LLC, the County’s dredge consultant.