Dredge Management Guidelines - the BIEAP and FREMP Website

3 For more detailed information
please see Lower
Fraser River Sediment Budget
Analysis: Final Report
(Northwest Hydraulic
Consultants, Feb 1999)
available through FREMP.
How the Sediment Budget is determined 3
A sediment budget for any reach of the Lower Fraser River may be written as:
S out = S in – S dredge + S spoil - ∆S channel where :
The sediment monitoring station is at Mission. The predicted sediment budget will be calculated for
the river each year with the objective of using the budget to manage for the long-term sustainability of
the river. The budget period will be calculated on a calendar year but will be adjusted to reflect the fact
that a “dredging year” extends from August of one year to March of the following year.
∆S channel
S in
S dredge
S out
S spoil
What is the Sand Registry and What is its Role?
The Registry is a database containing records of the amount of sand removed and/or added to the river
each year. The Registry is maintained by FREMP at the FREMP office.
The Registry will help monitor dredging performance against the budget in order to ensure that sediment
removal remains within the river’s budget. The Registry will also be used to refine periodically the
dredging budget to ensure that the model continues to reflect the hydrological reality in the river. The
Registry will occasionally be able to identify when excess sand may be available for use by various
industries. An example of when this might occur would be a year in which a large flood was expected.
What the Registry Contains
The Registry will contain the following information:
■ number of dredging licenses issued;
Definition
■ actual amount of sediment removed;
■ date and location from which sediment was removed;
■ particle size distribution of removed sediment; and
■ date, location, and type of disposal used.
The net change in navigation channel
storage of sediment expressed
as bed accretion or degradation
Sediment inflow to the study area
The net mass of sediment dredged
from the study area
The natural sediment outflow from
the study area
The quantity of material deposited
or disposed of in the river
Information Source
To be determined from the annual
River surveys
To be based on suspended sediment
data records collected at
Mission. The sediment outflow from
one reach will be the sediment
inflow to the next downstream
reach
To be determined from permits
received and reported by project
proponents
To be calculated from the equation
To be determined from permits
received and reported by project
proponents
16 Part 2: The Fraser River Sediment Budget and Sand Registry