NAME : SHAH HUSSAINROLL NO : 61BACHA KHAN UNIVERSITY CHARSADDA

River Discharge

-Volume or flow of water passing a gauging station in a river at a particular time.

-Amount of water originating from precipitation that reaches the channel – directly, from overland flow, throughflow and baseflow.

-discharge = velocity (m/sec) x cross-sectional area (m2)

-So… discharge measured in cumecs (cubic metres per sec)

Water balance

-Overall discharge from a drainage basin = product of the relationship between precipitation and evapotranspiration, and a number of factors which control the amount of water stored in the drainage basin…

-Therefore, water balance equation:

drainage basin discharge = pptn – (evap + transp) +/- changes in storage

Factors affecting discharge

Physical

-Basin size, shape

-Rock/soil type

-Drainage area and drainage pattern

-Height above sea level

-Surface water stores, eg lakes, glaciers

Factors affecting discharge

Meteorological

-Type of precipitation

-Rainfall intensity, amount and duration

-Distribution of precipitation across the drainage basin

-Factors affecting evapotranspiration (eg wind, temperature, humidity and season)

Factors affecting discharge

Human

-Land use

-Surface water stores, eg reservoirs

1. Basin shape, size

2. Geology

3. Soil type

4. Drainage density

5. Precipitation

6. Temperature

7. Land use