Hydrology: Fundamentals, Precipitation, and Infiltration

Comprehensive fill-in-the-blank flashcards covering the introduction to hydrology, the hydrologic cycle, precipitation measurement and spatial estimation methods, double mass analysis, and mathematical infiltration models (Horton, Philip, and Green-Ampt).

Hydrology is concerned with the occurrence, movement, distribution, and properties of water on and below the __________ surface.

Earth's

Hydrologists often use mathematical models and __________ to predict water movement and assess the impact of environmental changes on water resources.

Geographic Information Systems (GIS)

The branch of hydrology that examines interactions between water and the atmosphere is known as __________.

hydrometeorology

The branch of hydrology that studies groundwater in relation to geological formations is called __________.

hydrogeology

Temporary storage occurring when precipitation is caught by vegetation, buildings, and other surfaces before reaching the ground is called __________.

interception

The downward movement of infiltrated water through the soil and toward the groundwater zone is termed __________.

percolation

Evapotranspiration is defined as the combined loss of water through evaporation and plant transpiration, represented by the relationship __________ = $E + T$.

$$\text{ET}$$

During plant transpiration, water vapor is released into the atmosphere through small pores in leaves known as __________.

stomata

In warm clouds, droplets grow sufficiently large to fall as rain primarily through the __________ process.

collision-coalescence

__________ lifting occurs when moist air encounters a mountain or elevated terrain and is forced upward, resulting in a wetter windward side and a drier leeward side.

Orographic

Soft, opaque ice pellets formed when supercooled water droplets collect on snow crystals are called __________.

graupel

A graphical representation of the variation of rainfall intensity over time during a storm event is called a(n) __________.

hyetograph

A(n) __________ rain gauge records rainfall electronically by balancing a small container on a pivot that empties and triggers a count when filled to a certain level.

tipping bucket

A rain gauge that estimates rainfall rate by detecting the interruption, scattering, or absorption of a light beam by falling raindrops is a(n) __________ rain gauge.

optical

Lines drawn on a map connecting points of equal rainfall depth based on point rainfall data are called __________.

isohyets

In the Thiessen polygon method, the areal rainfall is calculated as a weighted average using the Thiessen weight given by the formula $W_i =$ __________.

$$\frac{A_i}{A}$$

Unlike Inverse Distance Weighting, Kriging models spatial correlation and calculates interpolation weights using a statistical function called a(n) __________.

variogram

The relationship used to convert point rainfall depth ($P_P$) to an equivalent areal rainfall depth ($P_A$) over a watershed is $P_A =$ __________ $\times P_P$.

$$\text{ARF}$$

__________ analysis is a graphical technique used to check the consistency or homogeneity of rainfall records by plotting cumulative values against cumulative reference station values.

Double mass

When adjusting an inconsistent rainfall record in double mass analysis to match the earlier slope $m_1$ from a later slope $m_2$, the correction factor is $C_f =$ __________.

$$\frac{m_1}{m_2}$$

The maximum rate at which a soil can absorb water under specific conditions is called the infiltration __________.

capacity

In a double-ring infiltrometer, the outer ring is designed to minimize __________ water movement while the inner ring measures vertical infiltration.

lateral

Horton's empirical infiltration equation expresses infiltration capacity as $f(t) =$ __________.

$$f_c + (f_0 - f_c)e^{-kt}$$

In Philip's infiltration equation $I(t) = S\sqrt{t} + At$, the parameter $S$ represents __________, which quantifies the soil's capacity to absorb water via capillary forces.

sorptivity

Differentiating Philip's cumulative infiltration equation yields the infiltration rate formula $f(t) =$ __________.

$$\frac{S}{2\sqrt{t}} + A$$

The Green-Ampt model simplifies unsaturated infiltration by assuming the presence of a distinct, sharp __________ separating the fully saturated zone from the drier soil below.

wetting front

In the Green-Ampt infiltration rate equation $f(t) = K\left(1 + \frac{\psi\Delta\theta}{F(t)}\right)$, the variable $\psi$ represents the __________.

wetting front soil suction head

Under the Green-Ampt model, surface ponding will occur only when rainfall intensity $i$ is __________ the saturated hydraulic conductivity $K$.

greater than

Under constant rainfall intensity $i$ exceeding $K$, the Green-Ampt formula for calculating ponding time is $t_p =$ __________.

$$\frac{K\psi\Delta\theta}{i(i - K)}$$