Hydrograph and Flood Concepts

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is a flood warning?

Notification that floodwaters are receding

A flood-control technique to manage water flow

Alert for heavy rainfall expected in the area

Advance notice that a flood may occur (correct)

What does a flood-control reservoir do?

Stores water for agricultural use

Generates hydroelectric power

Temporarily stores flood water (correct)

Holds water for recreational purposes

What is a flood wave?

Rise in streamflow to a maximum crest from various causes (correct)

A sudden rise in temperature caused by rain

A wave generated by strong wind in water bodies

A gradual increase in streamflow due to drought

What does a frequency distribution indicate?

How frequencies of varying values are distributed Signup and view all the answers

What is the purpose of a flowmeter?

To measure the rate of flow in a conduit Signup and view all the answers

What characterizes a flume?

A man-made channel with specific shapes and dimensions Signup and view all the answers

What defines the fresh/salt-water interface?

A surface separating fresh water from salt water Signup and view all the answers

What does the term flooding refer to?

Overflowing of water beyond normal confines Signup and view all the answers

What is defined as the part of a hydrograph where discharge is decreasing from a peak?

Falling limb Signup and view all the answers

Which term refers to the highest elevation of water level during a flood?

Flood crest Signup and view all the answers

What describes the technique used to compute the movement and shape change of a flood wave?

Flood routing Signup and view all the answers

What corresponds to the probability of a flood of a specific stage occurring in a given year?

Flood probability Signup and view all the answers

Which of the following describes natural marks indicating maximum flood stages on structures?

Flood marks Signup and view all the answers

What is the term for the protection of land areas from overflow due to flooding?

Flood control Signup and view all the answers

What type of gauge consists of a float that rises and falls with water levels?

Float gauge Signup and view all the answers

What term describes the nearly level land along a stream that floods only under high flow conditions?

Flood plain Signup and view all the answers

What is the definition of the peak-to-mean flow ratio?

The ratio of the peak discharge to its average discharge Signup and view all the answers

What does the Pearson distribution group relate to?

Probability distributions of varying skewness Signup and view all the answers

Which instrument is used to measure precipitation at a particular site?

Pluviometer Signup and view all the answers

What does the term 'polder' refer to?

An area protected from surrounding water Signup and view all the answers

What is meant by potential evapotranspiration?

The maximum water that can be evaporated and transpired Signup and view all the answers

What does 'persistence' in hydrology refer to?

The tendency of a time-series to recur Signup and view all the answers

What is the probable maximum precipitation (PMP)?

The statistical upper limit of precipitation for a specific duration Signup and view all the answers

What does point precipitation refer to?

Rainfall at a single observation point Signup and view all the answers

What does the term 'rating curve' refer to in hydrology?

Graph showing the relationship between stream stage and discharge Signup and view all the answers

What is the primary purpose of a recording rain gauge?

To record the depth of water from precipitation over time Signup and view all the answers

What does the recurrence interval indicate in hydrology?

An event's expected future occurrence based on historical data Signup and view all the answers

What is 'reservoir routing' used for?

To compute the movement and transformation of a flood wave Signup and view all the answers

What is meant by 'remote sensing' in hydrology?

Acquisition of data without physical contact with the subject Signup and view all the answers

What does the term 'response function' represent in a hydrological system?

The behavior of a system to a specific input Signup and view all the answers

What characterizes a 'representative basin'?

A basin used for intensive hydrological studies under unchanging conditions Signup and view all the answers

How is the 'rational method' typically expressed?

By using rainfall intensity and area to estimate peak runoff Signup and view all the answers

What is retention in the context of precipitation?

Precipitation that does not escape as surface streamflow Signup and view all the answers

What does return flow refer to?

Water that re-enters a stream channel or groundwater after use Signup and view all the answers

What is the significance of a return period?

Average interval until an event is equalled or exceeded Signup and view all the answers

What does the rising limb of a hydrograph represent?

The increase in discharge leading to a peak Signup and view all the answers

What does runoff refer to regarding precipitation?

Part of precipitation that appears as streamflow Signup and view all the answers

What is the primary purpose of a salt-dilution gauging method?

Help determine the discharge of a stream Signup and view all the answers

What does sediment concentration measure?

Ratio of weight of dry solids to weight of a water/sediment sample Signup and view all the answers

What is the definition of risk in the provided context?

Potential realization of unwanted consequences of an event Signup and view all the answers

Study Notes

Hydrograph

Falling Limb: Portion of a hydrograph showing a decrease in discharge from a peak.
Flood Hydrograph: Graph showing the variation of hydrological data, like discharge or stage, over a time period.
Rising Limb: Portion of a hydrograph showing an increase in discharge leading to a peak

Flood

Flash Flood: Flood of short duration with a high peak discharge.
Flood Control: Measures taken to protect land from overflow and minimize flood damage.
Flood Crest: Highest point of water level during a flood.
Flood Forecasting: Predicting flood characteristics like stage, discharge, duration, and time of occurrence.
Flood Frequency: Number of floods exceeding a specific discharge or stage over a certain time period.
Flood Marks: Natural marks on structures or objects indicating the maximum flood stage.
Flood Plain: Flat land bordering a stream, only flooded when the stream exceeds its capacity.
Flood Probability: Probability of a flood reaching or exceeding a certain stage or discharge in a year.
Flood Protection: Measures taken to protect land from overflow and minimize flood damage.
Flood Routing: Techniques used to calculate flood wave movement and shape changes through a river reach or reservoir.
Flood Warning: Advance notice of potential floods.
Flood Wave: Rise in streamflow to a maximum crest followed by recession, caused by precipitation, snowmelt, dam failure, or hydroelectric releases.
Flooded Area: The area covered by water when streamflow exceeds channel capacity or due to downstream damming.
Flooding: Overflow of water beyond normal stream boundaries or water accumulation in non-submerged areas.

Other Terms

Backwater: A raised water level in a stream caused by an obstruction.
Flow Duration Curve: A curve showing the percentage of time flow is equal to or greater than given amounts, irrespective of chronological order.
Frequency Analysis: Analyzing past hydrological events to predict future probabilities of occurrence.
Frequency Curve: A curve relating the possible values of a hydrological event to its occurrence frequency
Frequency Distribution: A specification showing how the frequencies of a population are distributed according to their variable values.
Probable Maximum Precipitation (PMP): The statistical upper limit of precipitation for a given duration in a particular basin.
Rate of Flow: The volume of water flowing through a river cross-section in a unit of time.
Rating Curve: A curve showing the relationship between stage and discharge in a stream.
Recession: Period of declining discharge following a peak, shown on the falling limb of a hydrograph
Return Flow: Flow returning to a stream or groundwater after use.
Return Period: The average time period for an event to be equalled or exceeded.
Risk: The potential realization of unwanted consequences of an event, a combination of probability and consequence value.
River: A large stream acting as the drainage channel for a basin.
River Basin: An area with a common outlet for surface runoff.
River Bed: The lowest part of a river valley, shaped by water flow and where sediment and runoff primarily move during interflood periods.
Runoff: The portion of precipitation that becomes streamflow.
Runoff Coefficient: Ratio of runoff depth to precipitation depth.
S-curve: A hydrograph resulting from an infinite series of sequential excess rainfall increments.
Sediment Concentration: The ratio of dry solid weight to water/sediment sample weight.
Sediment Discharge: Discharge of sediments from a stream at a specific cross-section.
Serial Correlation: Correlation between members of a time series and those lagging or leading by a fixed interval.
Significance: An effect is statistically significant if the hypothesis that the effect is absent is rejected.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

This quiz covers essential concepts related to hydrographs and floods. Learn about the different components of a hydrograph, such as the rising and falling limbs, as well as key flood terms like flood control and flash floods. Test your knowledge of how these elements interact in hydrology.