Soils of the - Agriculture and Agri-Food Canada

TSAWWASSEN SOILS (TS)
Location and Extent : Tsawwassen soils are limited mainly to areas along Boundary Bay and near the mout h
of the Fraser River. About 340 ha of pure map units and 100 ha of soil complexes dominated by Tsawwasse n
soils are mapped . The complexes are with Neptune and Seaview soils . Small areas of an anthropogenic varian t
of Tsawwassen soils also occur which consist mainly of sand dredgings from the Fraser River .
Topography and Elevation : The topography of Tsawwassen soils is gently undulating to undulating wit h
slopes less than 5 percent . Elevations range up to 3 m above sea level .
Parent Material and Texture : Tsawwassen soils have developed from coarse-textured, stone-free, recen t
marine beach deposits . Surface textures are loamy sand or sandy loam while subsurface and subsoil texture s
are mainly medium or coarse sand, sometimes containing lenses of gravelly sand . In some slightly depressio -
nal locations the lower subsoil is saline .
Soil Moisture Characteristics : Tsawwassen soils are moderately well to well drained . They are rapidl y
pervious and have low water holding capacity and slow surface runoff . In some lower topographic positions ,
temporary watertables sometimes develop in the subsoil due to heavy, prolonged rainfall or from tidal seepag e
through the coarse-textured material .
General Soil Description : The surface of Tsawwassen soils consists of up to about 10 cm of grayish-brow n
to black, very friable, sandy material . It is underlain by at least 50 cm of loose, variably coloured, medium t o
coarse sand, sometimes containing lenses and pockets of gravelly sand . It then grades to loose san d
containing common to occasional, reddish or brownish mottles . Soil reaction grades from very strongly o r
extremely acid in the surface to strongly or medium acid in the subsoil . Soil classification is Orthic Regosol.
Commonly Associated Soils : Neptune, Seaview, Benson and Mathews soils are often closely associated
with Tsawwassen soils . Neptune soils differ from Tsawwassen soils by containing substantial amounts of shell s
and other remnants of sea life ; they also have deep, black surfaces . Seaview and Benson soils usually occup y
lower landscape positions than do Tsawwassen soils and are poorly drained and strongly saline . Mathews soil s
occupy intermediate landscape positions, are moderately poorly drained and have loamy textures .
Vegetation : Cleared areas are used mainly for pasture and forage or for urban development . Uncleared areas
support coast Douglas-fir, western red cedar, Sitka spruce and a variety of deciduous shrubs and herbs .
Rooting depth is essentially unrestricted .
General Land Use Comments : (1) Agriculturally, Tsawwassen soils are severely limited by low wate r
holding capacity and nutrient content . With adequate irrigation and fertilization moderate amounts of most
crops can be produced . (2) Temporary watertables in the lower subsoil and potential incomplete septic tan k
effluent filtration by the coarse-textured material somewhat limits Tsawwassen soils for urban uses .
187