Write definitions for the following terms: hydrograph, hyetograph, abstractions, losses, baseflow, and excess precipitation. Cite your source for this information.
Solution
1) A hydrograph is a graph showing the rate of flow (discharge) versus time past a specific point in a river, or other channel or conduit carrying flow. The rate of flow is typically expressed in cubic meters or cubic feet per second (cms or cfs)
2) A hyetograph is a graphical representation of the relationship between the rainfall intensity and time. It is the plot of the rainfall intensity drawn on the ordinate axis against time on the abscissa axis. The hyetograph is a bar diagram
3) Abstractions/losses – difference between total rainfall hyetograph and excess rainfall hyetograph
4) Losses :
i) Depression Storage: The volume of water contained in natural depressions in the land surface, such as puddles.
ii) Interception : The process by which precipitation is caught and held by foliage, twigs, and branches of trees, shrubs, and other vegetation, and lost by evaporation, never reaching the surface of the ground. Interception equals the precipitation on the vegetation minus stream-flow and through fall.
5) Base flow:
Stream-flow which results from precipitation that infiltrates into the soil and eventually moves through the soil to the stream channel. This is also referred to as ground water flow, or dry-weather flow.
6) The volume of water from precipitation that is available for direct runoff
Direct runoff is the sum of overland flow and inter flow (water flow in the top soil layer).
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Write definitions for the following terms- hydrograph- hyetograph- abs.docx
1. Write definitions for the following terms: hydrograph, hyetograph, abstractions, losses, baseflow,
and excess precipitation. Cite your source for this information.
Solution
1) A hydrograph is a graph showing the rate of flow (discharge) versus time past a specific point
in a river, or other channel or conduit carrying flow. The rate of flow is typically expressed in
cubic meters or cubic feet per second (cms or cfs)
2) A hyetograph is a graphical representation of the relationship between the rainfall intensity
and time. It is the plot of the rainfall intensity drawn on the ordinate axis against time on the
abscissa axis. The hyetograph is a bar diagram
3) Abstractions/losses – difference between total rainfall hyetograph and excess rainfall
hyetograph
4) Losses :
i) Depression Storage: The volume of water contained in natural depressions in the land
surface, such as puddles.
ii) Interception : The process by which precipitation is caught and held by foliage, twigs, and
branches of trees, shrubs, and other vegetation, and lost by evaporation, never reaching the
surface of the ground. Interception equals the precipitation on the vegetation minus stream-flow
and through fall.
5) Base flow:
Stream-flow which results from precipitation that infiltrates into the soil and eventually moves
through the soil to the stream channel. This is also referred to as ground water flow, or dry-
weather flow.
6) The volume of water from precipitation that is available for direct runoff
Direct runoff is the sum of overland flow and inter flow (water flow in the top soil layer).
