Surface Runoff
1. SURFACE RUNOFF
INTRODUCTION:
Runoff means the draining or flowing off of precipitation from a catchment area through a surface channel enters into a stream channel.
It is convenient to visualize three main routes of travel; overland flow
(air hujan limpahanpermukaan), interflow, and ground water flow (air dari punca bawah tanah).
1 Runoff results from rainfall occurrence in a hydrologic catchment. Rainfall-runoff relations are Interflow/subsurface and base flow/groundwater flow
very important in hydrology.
2 Most work on the prediction of runoff requires past records.
3 The problem is that some streams are not gauged. Also, non-recording gauges only gives the volume of water and not intensities
4 There is the need to get records of stream flow and recording gauge information to predict runoff from rainfall.
5 Some empirical methods are available for predicting runoff in a catchment without the stream flow and recording gauge information.
Terms of water flow
Overland flow / surface runoff
Excess rainfall moves over the land surface to reach small channels. This portion of runoff is called overland flow.
Interflow / subsurface runoff
Rainfall that infiltrates the soil surface my move laterally through upper layers of soiland returns to the surface at some location is c
Ground water flow
Infiltrated water reaching saturated zone and moves through the soil as groundwater flow. It is also called base flow and dry weather flow.
Direct runoff
It means surface runoff, prompt interflow and rainfall on the channel surface.
Base flow
It means delayed interflow and groundwater flow.
Stream flow
Streamflow is a combination of baseflow and runoff. These vary along the stream.
Catchment Area
1 The area of land draining in to a stream or a water course at a given location is called catchment area / drainage area / drainage basin / watershed.
INTRODUCTION:
Runoff means the draining or flowing off of precipitation from a catchment area through a surface channel enters into a stream channel.
It is convenient to visualize three main routes of travel; overland flow
(air hujan limpahanpermukaan), interflow, and ground water flow (air dari punca bawah tanah).
1 Runoff results from rainfall occurrence in a hydrologic catchment. Rainfall-runoff relations are Interflow/subsurface and base flow/groundwater flow
very important in hydrology.
2 Most work on the prediction of runoff requires past records.
3 The problem is that some streams are not gauged. Also, non-recording gauges only gives the volume of water and not intensities
4 There is the need to get records of stream flow and recording gauge information to predict runoff from rainfall.
5 Some empirical methods are available for predicting runoff in a catchment without the stream flow and recording gauge information.
Terms of water flow
Overland flow / surface runoff
Excess rainfall moves over the land surface to reach small channels. This portion of runoff is called overland flow.
Interflow / subsurface runoff
Rainfall that infiltrates the soil surface my move laterally through upper layers of soiland returns to the surface at some location is c
Ground water flow
Infiltrated water reaching saturated zone and moves through the soil as groundwater flow. It is also called base flow and dry weather flow.
Direct runoff
It means surface runoff, prompt interflow and rainfall on the channel surface.
Base flow
It means delayed interflow and groundwater flow.
Stream flow
Streamflow is a combination of baseflow and runoff. These vary along the stream.
Catchment Area
1 The area of land draining in to a stream or a water course at a given location is called catchment area / drainage area / drainage basin / watershed.