chapter 11 soils and hydrology

Runoff

Portion of precipitation that runs to a surface stream over penetrating

Entry

Precept goes directly into the soil

Transmission

Verticals and horizontal percolation that can
occur throughout the entire depth of the soil layer

Storage:

can occur throughout the soil profile and is
manifested as

Surface runoff

: the
movement of water across
the soil surface toward
the stream channel

interflow:

the

relatively rapid movement

of water below the soil

surface toward the stream

channel

Baseflow:

the long-term supply of water that
keeps at least some water in the stream even
during extended dry periods

Infiltration:

the downward movement of water
through the soil surface, specifically, entering
the soil surface

how is percolation different from inflitatration?

(percolation refer to movement of
water within soil)

what happens when inflitration rates exceed precipitation rates?

no runoff occurs

Infiltration excess overland flow

too much precipitation leads to runoff

Saturation excess overland flow

soil sponge gets saturated. the soil then allows runoff

Interflow

Relatively rapid flow toward the stream channel

that occurs below the surface. flow happenx below surface but slower than runoff

Pre-event water

Pre-event water is water that

exists in the soil profile when

a storm begins and gets

displaced into the stream by

newly infiltrated water.

terms for water flow below surface

thouroughflow

interflow

subsurafce flow

Where does runoff occur

at and beneath the soil surafce. it is not just above.

what runoff is most common in urban areas?

infiltration excess overland flow

variable source area (VSA)

flow:

low-lying areas of the

landscape can saturate to

the surface due to rising

water tables and then

exfiltrating groundwater and

additional rainfall flows

from the saturated areas. (think of grandmas yard.)

what % of irrigation water is groundwater?

~40% of irrigation water is

groundwater