Hydrology exam two

texture

percent of clay, silt, and sand

porosity

volume of voids in a volume of soil

bulk density

used to compute porosity

degree of saturation

portion of pares that contain water

bernoulli’s equation

What equation describes the mechanical potential energy of a fluid in a system

bernoulli’s equation

What equation includes fluid potential due to gravity, velocity, and fluid pressure

high to low

water moves from ___ hydraulic head

Richard’s equation

a theoretical description of infiltration that solves Darcy’s for unsaturated conditions

Phillip’s equation

simplifies Richard’s by assuming ponded conditions, K is constant

Green and Ampt equation

Simplifies the wetting front as a clear boundary between saturated and unsaturated conditions because pressure at that boundary the hydraulic head is equal to zero, above the value will be positive and below it will be negative, K is constant

Horton’s equation

an empirical model of infiltration under ponded conditions

wetting front

region of rapid downward decrease in water content

What are the three conditions for infiltration?

ponding, no ponding, saturation from below

Phi-index

sed to estimate run-off by assuming a uniform loss

Excess precipitation models

phi index, initial then constant loss, constant fraction, curve number

confined

A saturated zone bounded from above and below by a formation with significantly lower hydraulic conductivity (K), where pressure is greater than atmospheric

unconfined aquifer

the upper boundary of the water is the water table and the surface is equal to atmospheric pressure. Total head and elevation head are equal.

Aquifer

A geologic unit that can store enough water and transmit it at a rate fast enough to be hydrologically significant (can supply water fast enough for use). Flow within aquifers is considered to be induced by a single coherent potential energy

field (water within an aquifer is hydrologically connected)

confining layer

A layer of low permeability that stores and transmits water slowly between aquifers

potentiometric surface

the confining layer that surrounds a confined aquifer