Aggregate | Mineral materials, such as sand, stone or
crushed rock. |
Antecedent catchment wetness | How wet the drainage area (catchment) is
immediately before the storm event. |
Anthropogenic | The study of the cumulative nature of human
presence and activity. |
Baseflows | Streamflow which results from precipitation
that infiltrates into the soil and eventually
moves through the soil and geology to a stream
or channel. |
Binder | Material used to bind layers of road surface
together or to each other. |
Bituminous | Material formed using bitumen, a tarry
substance. |
Catchment Area | A specified area where surface water from
precipitation collects and is discharged at its
lowest point through streams and rivers,
sometimes known as a drainage area. |
Caveats | A warning against certain acts; "a caveat
against unfair practices". |
Climatology | The meteorological study of climates and
their phenomena. |
Closed pipe systems | Drainage systems that are fully enclosed
i.e. underground pipes that do not
permit infiltration. |
Convective activity | Upward motion in the air due to the heating
and production of less dense air. Small summer
thunderstorms are typically convective
phenomena. |
Counter fort drains | A drain other than a filter drain running
parallel to a carriageway, surrounded by
granular material such as gravel. |
Culvert | A sewer or drain crossing under a road or
embankment. |
Cyclic | Recurring in cycles. |
Detritus | Loose matter resulting from the wearing away
or disintegration of a tissue or substance. |
Evapo-transpiration | Evaporation of water either by water passing
through a plant and evaporating from the leaf
stomata, or by water falling on a surface and
being evaporated. |
Filter drains | A perforated or porus pipe in a trench
surrounded with suitable filter material,
granular material or lightweight aggregate
fill, which permits water entry by
infiltration. |
Flood plains | Flood areas adjacent to rivers that are
inundated at times by the river. |
Flow capacity | The maximum volume of water which can be
transported through a particular size of
drainage pipe or other drainage structure. |
GCM | Global Climate Model |
Geotechnics | The science of designing structures in the
ground including design using soil as a
construction material. |
Greenhouse gases | Any of the atmospheric gases that contribute
to the greenhouse effect. |
Gullies | A small chamber covered by a steel grating
used in the drainage of surface water from a
carriageway. |
Hydrological | Related to the scientific study of the
properties, distribution, and effects of water
on the earth's surface, in the soil and
underlying rocks, and in the atmosphere. |
Inter-annual variability | Year to year variability
. |
IPCC | Intergovernmental Panel on Climate
Change. |
Isostatic | Condition of equilibrium whereby the Earth's
crust is buoyantly supported by the underlying
materials. |
NADICS | National Driver Information and Control
System, which controls Variable Message Signs
on the trunk road network. |
Open trench systems | Drainage systems that are not fully enclosed
i.e. swales, trenches etc. |
Orthography | The study of the physical geography of
mountains and mountain ranges. |
Parameterised | To describe in terms of parameters. |
Peak fluvial flows | The highest flows in rivers occurring after
storm events. |
Permeable geology | Soils and rock that are permeable by
water. |
Pore water content | The volume of water within the void space in
a soil. |
Pore water pressure | The pressure of the water within the void
space in a soil. |
Porosity | The ratio of the volume of voids to the
total volume of soil. |
Precipitation | Any form of water, such as rain, snow,
sleet, or hail, that falls to the earth's
surface. |
RCM | Regional Climate Model. |
Return periods | The average period of time between events of
a similar nature occurring. |
Rock fill | Rock used for filling drainage systems,
trenches etc. |
Rooting zone | The upper soil layer in which vegetation
takes root. |
Runoff | Rainfall not absorbed by soil. |
Saturation | The process of increasing the water content
of a material, ultimately reaching the level at
which no further increase is possible. |
Scouring | Damage resulting from debris transported in
water. |
Snowmelt | The water from melting snow. |
Soil moisture content | The amount of water present in the soil. |
Soil moisture deficits | A lack of moisture experienced in the soil
layer caused by low precipitation and
evaporation. |
Spatial | The physical dimensions of breadth, length
and height. |
Surface dressing | Material used to restore skidding resistance
in road surfaces, which also assists in sealing
the road surface against ingress of water. |
Thermal expansion | Expansion of a material due to a change in
temperature. |
Thermal growing season | Proportion of the year suitable for plan
growth based upon temperature conditions. |
Thermal inertia | The ability of a material to conduct and
store heat. |
Time Slices | Periods of time. |
UKCIP | UK Climate Impacts
Programme. |
Water conveying structures | A structure designed to carry water beneath
an obstruction, such as a culvert beneath a
road. |
Watercourse | A natural or artificial channel through
which water flows. |