Drainage Basin System Key Words
Input
Water coming into the system
all forms of moisture that reach the Earth’s surface e.g. rain, snow, sleet and hail.
Output
Water leaving the system
The evaporation of moisture from vegetation's stomata.
The transformation of water droplets (liquid) into water vapour (gas) by heating
into the atmosphere. The vast majority occurs from the oceans to the
atmosphere.
The movement of water in channels such as streams and rivers. The water may
enter as direct channel precipitation (it falls on the channel) or it may reach the
channel by surface runoff, groundwater flow (baseflow) or throughflow.
The sum of evaporation and plant transpiration from the Earth's land and ocean
surface to the atmosphere.
Store
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Water stored in the system.
Water that is caught and stored by vegetation.
Water that is retained by plants surfaces and that is later evaporated away or
absorbed by the plant.
Water that either falls through gaps in the vegetation all that drops from leaves or
twigs.
Water that trickles along twigs and branches and finally down the main trunk.
Water held on the Earth’s surface in lakes, ponds and puddles.
Is water that is stored in the soil within the plant's root zone.
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Is the degree to which soil moisture falls below field capacity. In temperate areas,
during late winter and early spring, soil moisture deficit is usually very low, due to
high levels of antecedent precipitation and limited evapotranspiration in prior
months.
Occurs in autumn when precipitation exceeds potential evapotranspiration –
there is some refilling of water in the dried-up pores of the soil.
Is the period (typically the first few months of the calendar year in temperate
regions) when soil is saturated and water cannot enter, and so flows over the
surface.
Is the process operating in summer by which water is drawn to the surface
through capillary action.
The storage of water underground in permeable rock strata.
Refers to all water stored in rivers, streams and other drainage channels.
Transfer/Flow
Water moving from one place to another.
Infiltration is the process by which water soaks into or is absorbed by the soil. (The
infiltration capacity is the maximum rate at which can be absorbed by a soil in a
given condition).
Water moves slowly towards the bedrock. (Depending on the permeability of the
rock this may be very slow or quite fast).
The very slow horizontal movement of water through rock. Groundwater refers to
subsurface water that is stored under the surface of the rocks. Baseflow refers to
part of the river’s discharge that is provided by groundwater seeping into the bed
of a river. It is a relatively constant flow although it increases slightly following a
wet period.
Water flowing through soil towards a river channel in natural pipes and percolines
(lines of concentrated water flow between soil horizons).
the movement of water over the surface of the land, usually when the ground is
saturated or frozen or when precipitation is too intense from infiltration to occur.
Water table – As the upper level of an underground surface in which the
soil or rocks are permanently saturated with water.
Recharge - Where water moves downward from surface water to
groundwater. Recharge is the primary method through which water enters
an aquifer.
Aquifer - Rock that can hold water.
Springs - Small flow of water flowing naturally from an underground
water source.