WK 1 Lecture: Discharge Measurements and Hydrographs

These flashcards cover key terms and concepts related to flow regimes and stream discharge variability as presented in the lecture.

Discharge

The volume of water flowing through a stream per unit of time.

Diurnal Variation

Daily variation in stream discharge that occurs throughout a 24-hour period.

Hydrograph

A graph showing the variation in discharge of a stream over time.

Flow Regime

The pattern of stream discharge over time in a catchment, focusing on annual patterns.

Basin Size

The area of land where precipitation collects and drains into a stream, influencing discharge characteristics.

Flashy Hydrograph

A hydrograph that shows rapid increases and decreases in discharge, often associated with a small watershed.

Mean Daily Discharge

The average discharge over a given day, used to compare flow regimes across systems.

Water Year

The annual period used for measuring and analyzing hydrological data, typically starting at low flow and ending at low flow.

Flood Return Interval

The probability of a flood of a specific magnitude occurring within a given time period.

Natural Flow Regime Paradigm

The concept that the structure and function of a river ecosystem are dictated by the patterns of temporal variation in river flow.

Magnitude of Flow

The amount of water in a flow event, particularly significant in defining floods.

Frequency of Flow Events

The number of flood or drought events occurring within a specific time frame.

Timing of Flow Events

The date during the year when floods or droughts occur.

Predictability of Flow Events

The regularity with which flood or drought events occur, influencing organism adaptation.

Rate of Change in Flow

The speed at which discharge conditions change in response to environmental factors.

Abiotic Drivers

Environmental factors, such as floods and droughts, that influence stream communities.

Biotic Drivers

Species interactions (e.g., competition, predation) that collectively influence ecological communities.

Drought

A prolonged period of below-average water availability in a stream.

Snowmelt Dominated System

A river system where the primary source of flow is from melting snow, leading to predictable flow patterns in spring.

Rainfall Dominated System

A river system where flow is primarily driven by rainfall, resulting in more variable and less predictable flow patterns.

Selection Pressure

The environmental factors that influence the survival and reproduction of organisms, impacting evolutionary adaptations.

Ecological Adaptations

Physical or behavioral traits in organisms that enhance their survival in specific environmental conditions.