| Tweet |
Custom Search
|
|
|
|||||
|
|||||
0015im.jpg){kind=tracking} 2.0 AGENCY CONCERNS
State and Federal agencies with permit authority for beach fill projects are concerned with public
health and welfare, and the effect of potentially toxic components, sedimentation, turbidity, and
potential impacts to the environment. Resource agency concerns regarding the characteristics of
beach fill are summarized below. BEACON proposes to address each concern. Specific actions
proposed by BEACON are presented in Section 4.0 of this report.
2.1
CHEMICAL COMPATIBILITY
Chemical compatibility of beach fill with the receiving beach is required to minimize adverse
effects to human health. The chemical content of material is evaluated through background
research and testing. The need for chemical testing is based on whether the resource agencies
have "reason to believe" that the material is contaminated (USEPA and USACE 1998). As an
example, material is considered most likely to be free of contaminants if it is composed of sand,
gravel, or other inert material, and is found in areas of high current or wave energy. Isolation of
the material from sources of contamination, based on previous testing and information about past
land uses at the source location may be utilized to conclude there is no "reason to believe"
contaminants are present. Chemical and biological contamination of sediments is addressed in
detail in the ITM (USEPA and USACE 1998). The ITM does not address terrestrial soils in as
much detail as it addresses dredged materials. BEACON proposes bulk chemistry testing of sand
sources prior to their use. The sampling and testing strategy is discussed Section 4.2.1 of this
report.
2.2
SEDIMENT GRAIN SIZE
Analysis of the sediment grain size of potential beach-fill material helps to determine impacts on
the receiving environment. Reef habitat, bottom-dwelling organisms, and kelp may become
covered when sediment settles from suspension. Also, contaminants tend to adhere to fine
sediment grains. Acceptable grain-size criteria and effects of turbidity caused when silt and clay
are suspended in the water column are covered only in more general terms in the ITM. The
acceptable percent fines (silt and clay) in beach fill is not specified, but the USACE generally
requires beach fill to contain a fines fraction that is within 10% of the sand at the placement
location (Russ Kaiser, USACE, Personal Communication, 2000).
Internal USACE guidelines (1989) to determine the acceptable fines content for Federal projects
within a certain percentage on the beach and out to a depth of -30 feet mean lower low water
(MLLW). The USACE method was devised internally for their dredging and beach
replenishment projects and is not necessarily applicable to this program, but it presents
background of a relevant analysis approach.
2-1
Moffatt & Nichol Engineers
|
 
|
||||
|
|||||
