| Abstract | A number of thematic maps of the Lower Rayong area are
constr u cted. The maps generated are geomorphologic map, ground
elevation map, geologic map, depth to grit map, engineering
geologic map, hydrological map, depth to water table map,
water table contour map, flood-prone area map, existing borrow
pit map, construction material map, existing landuse map,
foundation practice map, doc umentation map and fence diagram.
The landform features in the Lower Rayong area include hills,
terraces, alluvial plain and s hor e. Rock unit exposed in the
area is quartz - mica schist which appreciably weathered.
Surficial deposits consist of grit, colluvium, residual soil,
windblown sand deposits, marine terrace deposits at various
elevation, all uvium, sheetwash deposits and recent s h ore
deposits. A number of marine terraces deposits suggesting
several marine transgressions and/or tectonic uplifts. Grit
consists of SC, MH and ML. Colluvium is GC and GM. Residual
soil is SC, SM and CL. Windblown sand deposits is SM. Marine
terrace deposits commonly consists of SP, S M, SP-SM. Alluvium
commonly consists of SM, SC, SM-SC, SW-SM. Sheetwash deposits
is SM to SW-SM and recent shore deposits is SP. Grit, schist
and granitic rock form the foundation of the area and the
foundation condition are quite satisfactory. The water s upply
of the area depends mainly on surface water from the Dok Krai
Reservoir. The main groundwater aquifer is the grit. The
quality of groundwater is generally satisfactory but the
quantity is very limited. The area has good resources in terms
of construction materials except for crushed rock aggregates.
Waste disposal site and system need some attention. Flooding
is caused by the heavy rainfall, overflow from streams and
rivers, tide effects and the inadequate drainage capacity of
the main stream. Two types of geotechnical data base files of
the area were created. |