Lecture 18 - Hydrology

Plants slow ___________ which gives more time to______________.

runoff, infiltrate

The amount of water on Earth is relatively ____________.

constant

Evapotranspiration

evaporation + transpiration

Gully

moderate concentrated flow

Groundwater depletion

more used than replenished by nature

Wilting point

most capillary water is gone which causes plants to become unhealthy

Gravity water

unattached water that is pulled down by gravity

Throughflow

water infiltrates soil but some moves parallel to slope and emerges downslope to become overland flow

Effluent stream

water table higher than bed

Porosity

amount of open space between soil particles

Capillary water

available for animals to use

What source of runoff keep perennial streams flowing all year?

Baseflow

What does it mean when falling precipitation is "intercepted"?

It is caught on plants before reaching the surface

Transpiration

soil water taken up by plants and evaporated from surface of leaves

Aquifer

subsurface material that holds groundwater

Aquiclude

subsurface material with low permeability

Water table

upper limit of groundwater

Humid environments

use groundwater and it gets replaced by rainfall

Influent stream

water table below bed

Floods

when stream channel can't hold all the water

Groundwater

where all pore spaces filled with water

Permeability

ease with which water moves through soil

Dryland farming

farming in dry environment without irrigation

Runoff

flows downhill over surface

Sheetflow

flows in uniform sheet over surface

Intermittent stream

flows part of year because seasonally effluent

Hydrograph

graph of stream flow over time

Subsidence

groundwater helps hold up the surface

Vegetation tends to _______________ infiltration.

increase

Animals can increase infiltration by _______________________.

loosening soil

Arid environments

may not get replaced

Infiltration

precipitation seeps below the surface

Rill

small concentrated flow