Hydrology and Subsurface Flow Lecture Practice

Comprehensive vocabulary flashcards covering general hydrology, the hydrologic cycle, infiltration, precipitation, subsurface flow, evaporation, and rainfall-runoff relationships.

Hydrology

The science that deals with the occurrence, distribution, movement, and properties of water on Earth.

Hydrologic Cycle

The continuous movement of water between the Earth and the atmosphere; also known as the Water Cycle.

Evaporation

The process by which liquid water changes into vapor or gas due to the sun's heat.

Transpiration

The loss of water from plant leaves or stems into the atmosphere.

Transport

The movement of water vapor through the atmosphere from oceans to land.

Condensation

The process in which water vapor changes into tiny liquid droplets, forming clouds.

Condensation Nuclei

Tiny particles that aid in the condensation of water vapor in the atmosphere.

Precipitation

The primary mechanism that transports water from the atmosphere to the Earth's surface, such as rain, snow, or hail.

Groundwater

Water found beneath the Earth's surface that fills pores and cracks in soil and rock.

Infiltration

The process by which water enters and moves through the soil surface.

Runoff

Water that flows over the land surface toward streams and rivers; considered the phase of the hydrologic cycle most important to civil engineers.

Water Table

The boundary below which the ground is completely saturated with water; also referred to as the surface of the saturated zone.

King Scorpion

The ruler of Egypt around $3200\text{ B.C.}$ whose civilization utilized irrigation canals.

King Menes

The ruler who constructed a diversion canal to redirect the flow of the Nile River.

Sadd el-Kafara Dam

An ancient dam built around $2850\text{ B.C.}$ mentioned in the history of hydrology.

Hydrologists

Professionals who apply scientific knowledge and mathematical principles to solve water-related problems, including flooding and soil erosion.

Groundwater Hydrology

The branch of hydrology concerned with water stored beneath the ground.

Surface Water Hydrology

The branch of hydrology concerned with rivers, lakes, and reservoirs.

Hydrologic Model

A mathematical representation used by hydrologists to predict flooding and analyze water systems.

Field Investigation

The process by which hydrologists collect information such as water levels and water quality measurements.

Percolation

The downward movement of excess infiltrated water toward the groundwater table.

Igneous Rock

Type of rock formed by the cooling and solidification of magma.

Sedimentary Rock

Type of rock formed through lithification of sediments.

Metamorphic Rock

Type of rock formed when minerals recrystallize due to heat and pressure.

Weathering

The process involving the physical disintegration and chemical decomposition of rocks at the Earth's surface.

Saturated Zone

The underground zone that is recharged when infiltrated water reaches it and raises the water table.

Groundwater Recharge

The increase in groundwater storage due to infiltrating water.

Hydraulic Gradient

The slope or inclination of the water table, represented as $dh/L$ in Darcy’s Law.

Gaining River

A river that receives a water supply from groundwater flow.

Soil Moisture

A condition affecting infiltration where wet soils absorb less water than dry soils.

Porosity

Property that measures the percentage of open space in a material; often higher in round particles.

Permeability

The property describing the ability of a material to allow water to pass through it.

Infiltration Capacity

The maximum amount of water that soil can absorb per unit time under given conditions.

Hydraulic Conductivity

The measure of a fluid's ability to move through a porous medium, denoted as $K$ in Darcy’s Law.

Infiltrometer

A device used to measure the rate of water infiltration into soil, appearing in single ring or double ring concentric designs.

Green-Ampt Model

An infiltration model assuming homogeneous soil with constant hydraulic conductivity and water content.

Ponding Time

The time interval between the start of rainfall and the beginning of water ponding on the soil surface.

Cyclonic Precipitation

Precipitation caused by low-pressure systems and circular wind motion, categorized as frontal or non-frontal.

Convectional Precipitation

Precipitation caused by the rising of heated air.

Orographic Precipitation

Precipitation occurring when moist air is forced over mountains, typically falling on the windward side.

Leeward Side

The side of a mountain that receives less precipitation.

Return Period

The average time interval between storms of a given magnitude.

IDF Curves

Graphs relating rainfall intensity, duration, and frequency.

Tipping-Bucket Rain Gauge

A recording gauge that measures rainfall through the tipping of a bucket mechanism.

Normal-Ratio Method

The preferred method for estimating missing rainfall data when annual precipitation among stations differs by more than $10\%$.

Double Mass Analysis

A method used to check the consistency of hydrological or meteorological records.

Confined Aquifer

A geologic formation containing water trapped within sediment by at least one impermeable confining layer.

Aquitard

A layer that slows but does not completely stop the passage of water.

Aquiclude

A layer that is impermeable and does not allow any amount of water to pass through.

Henry Darcy

The individual who formulated Darcy's Law in $1856$, which forms the scientific basis for fluid permeability.

Potentiometric Surface

The level to which water rises inside a borehole drilled into a confined aquifer.

Artesian Flow

Occurs when water flows out of a borehole under natural pressure.

Thiem Equation

Also called the equilibrium equation, it determines piezometric head at a radial distance from a pumping well.

Drawdown

The distance the water level is lowered at a given point during well pumping.

Cone of Depression

The conic shape described by the drawdown curve in three dimensions.

Transmissivity

A value equal to $K(b)$, where $b$ is the thickness of a confined aquifer.

Penman-Monteith Equation

A general combination equation used to solve heat and water vapor diffusion plus energy balance.

Potential Evapotranspiration (PET)

The maximum possible evapotranspiration expected under unlimited water supply.

Albedo

The fraction of solar radiation reflected from a surface; also known as the reflection coefficient.

Stefan-Boltzmann Constant

A constant used in radiation calculations equal to $2.01 \times 10^{-9}\text{ mm/day}$.

Eddy-Covariance System

A high-precision system directly measuring turbulent fluxes of water vapor, heat, and momentum.

Stomatal Transpiration

Transpiration occurring through tiny leaf openings called stomata.

Vapour Pressure

The pressure exerted by water vapor above a liquid surface; higher values reduce the evaporation rate.

Tensiometer

An instrument used to measure soil moisture tension or the suction force exerted by plant roots.

Psychrometer

A type of hygrometer that calculates relative humidity using dry-bulb and wet-bulb thermometers.

Lysimeter

An instrument tracking precipitation and soil water balance to measure actual evapotranspiration.

Bowen Ratio

The ratio describing the distribution of heat between sensible heat and latent heat flux.

Interflow

Water that infiltrates the soil and moves laterally through upper layers to a stream; also called Through Flow or Storm Seepage.

Base Flow

Delayed flow reaching a stream as groundwater, providing dry-weather flow in perennial streams.

Direct Runoff

Runoff entering a stream immediately after rainfall, including surface runoff, prompt interflow, and snow-melt.

Virgin Flow

Stream flow in its natural condition, completely unaffected by human works; also called Natural Flow.

Ephemeral Stream

A stream that lacks base-flow contribution and only flows in response to storms.

Intermittent Stream

A stream that flows during the wet season but dries up when the water table drops below the stream bed.

Unit Hydrograph (UH)

A graphical representation showing runoff over time resulting from $1\text{ cm}$ of effective rainfall over a specific duration.

SCS Curve Number Method

A watershed management method abbreviated as SCS-CN.