CHAPTER
TWO: PHYSICAL LANDSCAPE FEATURES
GEOLOGY
The geology of Branford is dominated by basalt and shale
deposits towards the northern and western portions of
the Town and granite and gneiss deposits along the central
and eastern portions of the Town (Figure
1: Geology). Most of these deposits are of Mesozoic
Era origins and were formed between 225 million to 65
million years ago. Much of the geology runs in a diagonal
from northeast to southwest and can be divided into
sections based on fault line scarps and rock contacts.
In the northwestern portion of the Town, there is a
prominent high angle fault (Eastern Border Fault of
the Totoket Mountain Range) that cuts across the area
on a diagonal (Figure
1: Geology). This land feature most probably was
formed during the mid Mesozoic Era, in the period known
as the Jurassic. It is a fault line that contains the
Town's highest natural elevations and much of the Saltonstall
watershed and is most evident as one travels along Brushy
Plain Road. The elevations in this area are steep and
highly contoured and the bedrock in this section is
dominated by basalt (volcanic in origin) and sandstones
with some shales (sedimentary rock) mixed throughout.
Other bedrocks here include hornblendes (ferromagnesian
silicates), arkose brownstones (sandstones) and dolerite
(ophidic diabase).
Just south of the Eastern Border Fault, there are a
series of smaller faults and a sandstone (Portland Arkose)
outcrop that extends from the high angled fault. The
southern-most portion of the Town's western flank is
a gneissic deposit that is probably continental in origin.
Along much of the central and eastern portions of the
Town, the bedrock is dominated by gneisses and granites
including the Branford Gneiss in the center of Town
and the Stony Creek granites and gneisses along the
eastern portions of Town. The latter, the Stony Creek
granite, is one of the most famous granites because
of its use in building materials of such places as Grand
Central Terminal in New York City.
The geology of the region has had an impact on land-use
and economics of the Town. Besides the Stony Creek Granite
noted above, trap rock has also been mined in the area
(e.g., the south end of Beacon Hill). Trap rock is rock
that was laid down by magma flows as lava dikes and/or
flow rocks. These materials are cut and broken into
pieces of various sizes and used for road-beds and other
construction activities (e.g., stone armor at outfall
pipes). Glacial erratic and till (together are referred
to as glacial debris) have been quarried as well and
make up a significant portion of the Tilcon mining in
the area. This glacial debris is also used for road-beds,
foundations and other activities where adequate drainage
and compaction are important.
SOILS
Due to the impact of glaciers during the Pleistocene,
many areas of Branford were scraped clean of their soils,
and bedrock is still exposed in many places. In areas
where soil has developed they tend to be fairly young
when compared to more southerly regions of the country.
The soils of Branford (Figure
2; Soils) are the result of extensive weathering
and reworking of glacial till material, exposed bedrock
and some fluvial or sedimentary deposits. Much of the
soil varies between sandy loams and loams with mucky
peats locally important, particularly along the coastal
portions and larger river systems. Large sections of
soil are now classified as udorthents or soils that
have been disturbed by human activity. These are most
prominent in the downtown area and along industrial
and commercial developments that follow Route 1 and
Interstate 95, in particular.
Although there are dozens of soil types within the Town,
the soils in Town can be divided into six main variants;
Wethersfield-Wilbraham-Ludlow, Hollis-Charleton, Cheshire-Yalesville,
Holyoke-Cheshire, Cheshire-Holyoke and the Branford-Manchester.
The Wethersfield (well drained sandy loam)-Ludlow (course
loam and well drained with acidic sublayers)-Wilbraham
(poorly drained course loams) variant is a course loamy
mix found in level to steep grades on till uplands with
a fragipan prominent in the subsoil layers. These soils
tend to be poor to well drained and are found along
the western and eastern portions of the Town. The Hollis-Charlton-Rock
Outcrop variant is found mainly along the eastern flank
of the high angle fault and is a course loamy soil found
on steeper grades. The Charleton Series soils are brown
to olivine in color on slopes of 3-35% and acidic sublayers
while the Hollis Series is a fine sandy dark brown loam
with strongly acidic sublayers over unweathered schist,
gneiss, basalt and granite bedrock. The Cheshire-Yalesville
variant is a well drained (3-35% slopes) course loam
overlying till found primarily along the northern portions
of the high angle fault. The Cheshire Series soils tend
to be brown towards the surface and reddish brown in
color with depth and strongly acidic in the subsurface.
The Yalesville Series are course loams with a reddish
brown color and more common on hillsides and only moderately
acidic in subsurface layers. The Holyoke-Cheshire and
the Cheshire-Holyoke variants are prominent along the
northern and eastern boundaries of Town. Both types
are loam to course loam soils with the Cheshire-Holyoke
more common on till and exposed bedrock and the Holyoke-Cheshire
typical of the broader till plains. The Holyoke Series
soils are dark gray to reddish brown with depth and
tend to be found in more shallow areas. Like the Cheshire
soils, it tends to be strongly acidic in the subsurface
layers. The Branford-Manchester variant is common through
the central portion of Town and is a well drained course
loam to sandy loam located over outwash plains and terraces
(0-8% slopes). The Branford Series soils are the result
of weathered arkose and other sandstones, shale and
conglomerate and are typically reddish brown in color
and loamy to course loam in texture. The Manchester
Series soils are sandy and excessively drained and tend
to be yellowish red gravelly mixtures. Both the Branford
and the Manchester Series are strongly acidic in the
subsurface layers. All of these soils can support agriculture
(many are excellent for growing orchards) depending
on the crop and the texture, slope and acidity of the
soil.
Other soils types worth noting include the udorthents,
urban and mucks. Udorthents are soils that have been
disturbed by human activity, commonly development. These
soils are characterized by cut or borrow areas, filled
areas or some combination of both. The natural soil
pedon (footprint) has been disturbed and soil permeability
will vary depending on source, compaction, and use.
Urban soils are those that have been disturbed and paved
or built upon. They no longer are capable of supporting
woodlands and subsurface layers are no longer important.
Mucks are a designation that includes wetland soils
ranging from poorly drained floodplain deposits to peats
(e.g., Westbrook mucky peat). In Branford these soils
are common along the coastal marshes and swamps associated
with river and ponds. They are very dark brown to black
in color and have a high percentage of organic material
in the soil matrix (both decomposed and macro-organics).
They are always wetland soils and are therefore, subject
to both inland and coastal wetland regulations. These
soils are typically poorly drained and friable in structure
that renders these soils inadequate for most agriculture
(too wet) and construction projects (compaction).
TOPOGRAPHY
In general, the Town of Branford slopes from the northwest
to the southeast with the highest natural land elevations
associated with the high angle Jurassic fault (sometimes
referred to locally as East Rock) (Figure
3: Topography). As expected, there is also a general
slope from the north to the south as one approaches
the coast. The highest elevations in Town are about
320 feet above sea level and the lowest are just below
sea level (negative 2 ft) in the rivers and mud flats
exposed to tides. Much of the Town (particularly the
central portion of the Town) lies at about 50 to 70
ft above sea level except in those areas in proximity
to the major rivers (i.e., Branford River). The topography
also delineates the watersheds in town with the Branford
River making up the largest drainage way (see Water
Resources Chapter).
Topography and elevations will often help determine
the value of a parcel of land. If the parcel is too
steep, building and farming cannot be accomplished and
the land value declines. The proper relief on the landscape
assures drainage and often helps dictate soil properties.
A more gradual slope also requires less engineering
and fewer expenses to develop. Lower elevations often
denote proximity to water. Although many people prefer
lands at these lower elevations for the amenities they
offer (e.g., boating, coastal views), they also are
problematic because of the danger they pose to flooding.
Some of Branford's most expensive parcels of land are
also some of the most exposed areas to potential storm
damage and flooding. Except for controlling building
in a wetland or watercourse, there is presently no plan
to reduce or eliminate development in these areas.
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