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. |