HYDROLOGY

What?

The study of water on the earth’s

surface and in the

Terms Drainage basin

What?

It is an area of land drained by a river & its tributaries

Flow diagram

A system

It is a system because it has input, output and within this system some of the water is stored in lakes, soil or passes through a

series of transfer of flows.

Rainfall –discharge relationship with

drainage basin

Water balance

precipitation

Evapotranspiration

interception

throughflow

stemflow

infiltration

percolation

Channel flow

Overland flow

Is a simple equation which describes how precipitation may be

accounted for within a drainage basin

P= Q+E+ SP: PrecipitationQ: Total stream flow/runoffE: EvapotranspirationS: Storage (soil and bedrock)

Soil moisture balance

1. Winter- PPT>EVT = soil moisture surplus, result runoff & rise river level2. Summer-PPT<EVT=human & plants utilized water from soil store-depleted & fall river level3. Autumn-PP>EVT,surplus water recharge soil until reach field capacity.

W.B. varies with time & places

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Why importance?

Varies between dev and developing (deficit and surplus)

Depends on how obtained, what it is used for,Problems it creates in terms of supply & demand.

-Storm hydrograph?-Characterisctics/terms-interpretation-Why differ-Factor control drainage basin on storm hydrograph

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