Dredging projects are often superficially compared by some cost-per-cubic-yard of mud to be processed. These comparisons are often invalid, either because they do not include all the ancillary costs of the process or, compare unlike conditions. For example, many costs cited for specific disposal options do not include dredging and its associated costs, like disposal of debris and decanting of dredged water. Other costs cited for disposal options are for dredged material delivered to the site, i.e., omitting the costs of de-watering, debris removal and disposal, and the cost of dredging and sizing. Not to mention that dredged material in a scow has become "fluffed," and will occupy up to one-third more space than the material in the channel before dredging, with the resulting additional cost. Such a project cost is per-scow-yard, not per-survey-cubic yard.

Here follow some of the basic considerations in comparing actual costs of dredging projects.

Survey Cubic Yard
· The main unit of measure as laid out in contracts by the Army Corps and Port Authority is the Survey Cubic Yard. (For all practical purposes, one yard of wet mud is about one ton in weight).
· In short, it is a cubic yard of mud, sand etc. lying on the channel bottom.
· Specifically, it is the difference between the pre-dredging and post-dredging survey, ie, the true amount of volume that needs to be moved.

Scow Cubic Yard
This is a yard of dredged material as it sits in a scow after being removed from the bottom. It is less compact ("fluff factor") and has had some water removed from it. It can be from one-fifth to one-third less than a Survey Cubic Yard. For instance, 100 survey cubic yards that must be removed from the bottom might amount to 130 scow cubic yards by the time it is processed.

Analysis
Testing and sampling is usually done prior to contracts by the contracting agency, but additional sampling costs may pertain (like testing along the line for material going to Pennsylvania)

Dredging
The per-yard cost of actually moving the mud from the bottom into a scow. About $ 8/ yard.

Debris Removal and Disposal
Dredged material from the bottom can contain up to 20% debris that has washed in to the channel, from cars to telephone poles. This debris must be separated from the mud and land-filled separately at a much greater per-yard cost

De-watering
Dredged material is about 64% water. After dredging, a certain amount of water will collect on the top of the scow, along with the water brought on board by the clam shell. This water must be removed from the top of the scow, usually pumped off to another scow and either treated or piped into sewage treatment.

Tipping Fees
the term used to describe the charge for the use of a facility exclusively. This may sometimes include a fee for the local community, etc.

Guaranteed Volume, or Daily Volume Capacity
The limiting factor for any project is the amount of mud that can be processed in a day. Depending on the level of resources to pay for dredges and scows, it is usually the dock-side processing facility that limits how much mud can be processed each day. The smaller the capacity the more costly the over all

Pertinent Questions to ask when a per-yard cost is given

1.) How does your volume equate with a Survey Cubic Yard?
2.) Can you take the material as dredged?
3.) What will you do with the water?
4.) Is debris removal and disposal included in the price?
5.) Is there a restriction on the type of material you will take?
6.) Does this per-yard cost include dredging, and all the above factors?