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0046im.jpg){kind=tracking} 4.0 SAND SOURCES
Potential sand sources have been identified as part of the program, including flood control debris
basins, river and slough sediments, landslide material, decommissioned dams, and material from
miscellaneous construction activities. This section identifies and attempts to quantify these
sources. Note that only first order estimates are possible at this time due to limited data available.
Debris basins and other sources of sediment (Goleta Slough, Calleguas creek, etc.) provide a
tremendous amount of sediment every 5 to 10 years (e.g., 1969, 1978, 1983, 1995, and 1998).
The debris basins and estuaries in Santa Barbara County alone could supply approximately
500,000 cy in heavy rainfall years as was demonstrated in 1995. This means that approximately
2,000,000 cy of sediment could have been placed on Santa Barbara beaches over the past
25 years for an average annual contribution of 80,000 cy. The annual average contribution to
the Santa Barbara Littoral Cell from the Santa Ynez Mountain group is approximately
180,000 cy, so placement of sediment from debris basins and other drainage courses subject to
sedimentation onto Santa Barbara's beaches would be a significant benefit. (BEACON 2000)
4.1
SOURCE LOCATIONS AND VOLUMES
A list of potential sources and possible volumes was created for each beach fill site and is shown
in Table 4.1. The proximity of these sources to the proposed beach fill sites are shown in
Figure 4-1 for Santa Barbara County and Figure 4-2 for Ventura County. The debris basin
volumes were estimated using the total debris capacity of all basins in each county, then
multiplying by 20%, which represents the percent of beach quality material estimated to be
contained within the basins (Karl Treiberg, County of Santa Barbara, personal communication,
December 2000). The Goleta Slough and Carpinteria Marsh volumes were estimated using
historical dredge volumes (Karl Treiberg, County of Santa Barbara, personal communication,
December 2000). It is important to note that these are only estimates and the volumes change
because of weather conditions; debris basins can reach capacity more that once in a season, or
not reach capacity for many years. The potential volume of landslide material was estimated by
Wayne Johnson, Maintenance Area Manager of Caltrans District 7 for Ventura County (personal
communication, December 2000), and Ken Nirenberg, Maintenance Area Manager Caltrans
District 5 for Santa Barbara County (personal communication, December 2000), and indicates an
average yearly volume. Production of landslide material is also heavily dependent on the
weather, since wet weather causes more landslides to occur and therefore more beach quality
sand may become available.
4-1
Moffatt & Nichol Engineers
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