What are the uses of flow duration curve?

Flow duration curves have a long history in the field of water-resource engineering and have been used to solve problems in water-quality management, hydropower, instream flow methodologies, water-use planning, flood control, and river and reservoir sedimentation, and for scientific comparisons of streamflow …

What information does the flow duration curve give on the nature of the catchment?

A flow duration curve characterizes the ability of the basin to provide flows of various magnitudes. � Information concerning the relative amount of time that flows past a site are likely to equal or exceed a specified value of interest is extremely useful for the design of structures on a stream.

How do you construct a flow duration curve?

1. Steps for drawing Flow Duration Curve

1. Calculate the total number of data, say N.
2. Give rank to the data for the data 1,2,3,…., N; say n.
3. Compute frequency(f)
4. Compute the probability of exceedance(p)
5. Now place the discharge in descending order.
6. Draw the probability of exceedance or % of the time versus discharge.

What is Q95 flow?

For example, Q95 is the flow exceeded 95% of the time and is typical of a dry summer flow. Q5 is the flow exceeded 5% of the time and is equivalent to a full spate. FDCs are best derived using long-term local gauging station data.

What is a flow-duration curve and what is its relevance in hydrology?

The flow-duration curve is a cumulative frequency curve that show the percent of time specified discharges were equaled or exceeded during a given period. It combines in one curve the flow characteristics of a stream throughout the range of discharge, without regard to the sequence of occurence.

What is hydrograph flow-duration curve?

Explanation: The hydrograph is a graph which shows the variation of stream flow with respect to time for a particular river site. The time can be hour, week, month or year. Total volume of flow upto any time given by the area under the curve upto that time.

What is a flow-duration curve in hydrology?

ABSTRACT. The flow-duration curve is a cumulative frequency curve that show the percent of time specified discharges were equaled or exceeded during a given period. It combines in one curve the flow characteristics of a stream throughout the range of discharge, without regard to the sequence of occurence.

What does load duration curve represent?

Load duration curve indicates the variation of the load, but with the load arranged in descending order of magnitude. Load duration curve give the number of hours for which a particular load lasts during a day.

What is baseflow in hydrology?

Base flow is a portion of the stream flow that is not runoff; it is water from the ground, flowing into the channel over a long time and with a certain delay.

What does baseflow index mean?

The BaseFlow Index (BFI) is defined as the ratio of long-term mean baseflow to total streamflow. Knowledge of the BFI is not directly available for ungauged catchments and hence for most of the terrestrial land surface.

What does a load duration curve represent?

What is a flow duration curve in hydrology?

A graphical representation of runoff is called a flow duration curve. It is denoted by FDC. It relates flow rate with duration. Discharge and time are calculated at first. The FDC is then plotted which is used to learn or study floods, evaluating many dependable stream data, designing drainage works, etc.

How do you construct a duration curve?

Flow duration curves can be based on daily, monthly or annual flows and constructed for periods of interest such as a whole year, seasons, high or low flow periods, or, for example, during a period of fish migration. They may use the whole period of record, or parts of the record, to analyse variability.

How to draw flow duration curve in Excel?

Steps for drawing Flow Duration Curve 1. Calculate the total number of data, say N. 2. Give rank to the data for the data 1,2,3,…., N; say n. 3. Compute frequency (f) 4. Compute the probability of exceedance (p) 5. Now place the discharge in descending order. 6. Draw the probability of exceedance or % of the time versus discharge.

Why does the Le Sueur River change flow duration curves?

Flow duration curves are shown for two different time periods in the Le Sueur River, southern Minnesota. Changes in flows are attributed to changes in artificial drainage of agricultural fields, as well as changes in precipitation and crop type. See Schottler et al., (2014) Hydrological Processes for more information.