Module 1- Hydrological Cycle-1

8/11/2019 Module 1- Hydrological Cycle-1

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1. Hydrology for Engineers, Linsley2. Hydrology for Engineers , Wilson3. Hydrology in Practice, E. Shaw

S O Dulo

FCE 425 - Hydrology I (45 hrs)


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S O u o

Syllabus (45 hrs) Introduction. Hydrological cycle.

Rainfall and Rainfall data analysis.

Evaporation and transpiration: factors and methods ofcomputation. Infiltration and Percolation.

Runoff: factors affecting runoff, stream flow measurement andrating curves determination.

Streamflow data analysis. Subsurface water: soil-waterrelationship and measurement of soil moisture.Determination of permeability.

Lab Experiments: Measurements of weather parameters likeprecipitation, sunshine, evaporation, wind speed, calibrationof instruments.

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Course requirementsAttendance

Course work 20

Cats 10 Exams 70

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Definition Hydrology is the study of water of the earth

The study includes

Precipitation Movement over land

Movement below the ground surface

Evaporation and transpiration from land, water and

plants Condensation and reprecipitation

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Introduction

1950-1970Policy

WRM is a primary engineering task to builddams, lay pipelines, install pumps, andoperatesystems

TodaysPolicy

WRM must pursue sustainable development

with measures that manage water for humansystem, but at the same time protect andnature natural systems for the benefit of futuregenerations


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Introduction

Potable water is most valuable and underappreciated resource of our planet.

Why? Because in many locations, the "aquifer" is hundreds

of meters below ground and extends over a vast areathat includes multiple municipal and state

boundaries.


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Introduction

Over 70 % of the earth's surface is coveredwithwater,but < 0.5 % of this water is usable freshwaterresource.

All the remainderof the water is salt water.

Thewateron this planet movesthrough a cycle thatis the ultimate solar power driven system and the cycle

is in dynamic equilibrium. Water is constantly changingposition, phase, and

form


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World Water Total 97.2 % Ocean 2.8 % Fresh

2.15 % glaciers 0.65 % ground

water 0.0001 %

streams 0.009 % lakes 0.008 % seas 0.005 % soil 0.001 %

atmosphere


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eWater

Cycle


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The Water Cycle

Powered by the Sun- Solar Power


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Basic Cycle

Ocean

EvaporationEvaporation (ET)

runoff

Precipitation

Aquifer

Infiltration

Evaporation

Precipitation

Evaporation/ET

Surface Water

Groundwater


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More Detailed Cycle Components

Ocean

EvaporationEvapo-transpiration

runoff

Aquifer

Infiltration

Recharge

Evaporation

Precipitation

Precipitation

Evaporation/ET

Surface Water

Groundwater


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More Detailed Cycle Components

Ocean

EvaporationEvapo-transpiration

runoff

Water

Supply

Dischargetreated water

Salt Water IntrusionAquifer

Infiltration

Recharge

Evaporation

Extraction

Precipitation

Precipitation

Evaporation/ET

Surface Water

Groundwater

Soil moisture

Infiltration (Art)

Extraction

Return flow

Treated water Aquifer intrusion

Soil moisture

Soilmoisture


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Components of the Water Cycle

First The Ins

Solar Energy InputPrecipitation

Condensation

Well Injection

Irrigation

The OutsEvaporation

Transpiration

Infiltration

Percolation

Runoff

Groundwater FlowSurface water Flow

Well Pumping

water cycle


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PrecipitationTypes of Precipitation

Natural

Rain

Snow

IceHail

Condensation/ Dew

Man-Made

Irrigation

Wastewater Applications


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Hydrologic Cycle -Transpiration

Water vapor emitted fromplant leaves

Actively growing plantstranspire 5 to 10 times asmuch water as they can hold atonce

These water particles thencollect and form clouds


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Interception

Infiltration / Percolation

Canopy Interception

Percolation

Infiltration

Infiltration- Movement Water IntoSoil

Percolation - Water Movement

Through (IN) the Soil


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Evaporation / Transpiration

Evapotranspiration

Evaporation- Driven byThermal

Gradient and Moisture

DifferenceStomata


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Runoff / Overland Flow

When Rainfall Rate Exceeds

Infiltration Runoff is Generated

Low Infiltration

Causes - Overland Flow-

Loss Organic Material

Uncontrolled Runoff

Causes Erosion


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Basic Cycle

Temperate climate Semi-arid climate Arid climate

% mm % mm % mm

Total precipitation 100 500 - 1500 100 200 - 500 100 0 - 200

Real evapotranspiration ~ 33 150 - 500 ~ 50 100 - 250 ~ 70 0 - 140

Groundwater recharge ~ 33 165 - 495 ~ 20 40 - 100 ~ 1 0 - 2

Surface runoff ~ 33 165 - 495 ~ 30 60 - 150 ~ 29 0 - 58

Approximate annual hydro log ica l budget


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SW/GW relations - Humid vs Arid Zones

A. Cross section of a gaining

stream, which is typical of humid

regions,where groundwater recharges

streams

B. Cross section of a losing stream,

which is typical of arid regions,

where streams can recharge

groundwater


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1. Cycle Component ConceptsStandard Concepts (Physical)

Precipitation

Evaporation/Evapotranspitation

Surface Water

Groundwater

Ecosystem & Use Related (Basin/Watershed Perspective) Green water (Terrestrial ecosystems, Crops, Wetlands)- water that is

directly used for biomass production and lost in evaportaion

Blue water (Throughflow & return flow)

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2. The ecosystemwhere the water is !

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BOGS

AQUIFERS


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Blue & Green Water - perspective

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Precipitation the basic water resource

GW

GW

GW

GW

GW

Adapted from: GWP (M. Falkenmark), 2003, Water Management and Ecosystems: Living with Change


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Blue & Green Water

Pathways

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Consumptive water use by terrestrial ecosystems as seen in a global perspective. (Falkenmark in SIWI Seminar 2001).

percentages


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3. Ground Water Considerations

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Special considerations:

Supply sources are not as temporal as surface waters

Commonly more stable both from a quality and quantity

viewpointConsistent good quality with low treatment costs

Widespread availability away from river courses ( in good host rock &climatic settings)

Practical expansion and development pathwayaugmented

as neededCan be independently developed in its early stages of

development


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3. Ground Water Considerations

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3. Basin & aquifer boundaries: real or political ?

Waters in the past have rarely been managed at basin or

aquifer scales.WHY??

- Politics and power structures

- Professional & Institutional jealousy

- Turf - donor/funding/research/grants

- Laws (archaic and intransigent)

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2. Watershedsboundaries and divides ?

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Source: Modified from IHP-VI, 2001-ISARM

Country 1

Country 2

Country 3


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3. Basin & aquifer boundaries: real or political ?

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CONCLUSIONS:

1) Act ive ly challenge non-hydro log ic boundaries.

2) Ground and surface water boundar ies can di f fer.

Country 1

Country 2Country 3


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WHAT ARE OTHER COMPONENTS

IN THE CYCLE TODAY?

Soil water

Extraction schemes

Artificial recharge Return flow

Treated water - reuse

Instrusion

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What is weather? Weather describes the

state of the atmosphere

at any particular time. Weather can be

described in terms oftemperature,precipitation (snow, rain

& hail), wind speed anddirection, visibility andcloud amounts.


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What is Climate? Climate describes the

average weather of a

particular part of theworld at different timesof the year

In Britain we wouldexpect cool summers and

mild winters withmoderate rainfallthroughout the year


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The Weather Station Aweather station

makes continuous

measurements ofdifferent aspects of the

weather.

Weather stations use

standard instruments sothat their readings canbe compared.


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Temperature Temperature is recorded

using thermometers

housed inside aStevenson screen

Weather stations recordboth air temperature and

the temperature of theground


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Temperature: The Stevenson Screen

Why is the screenpainted white?

Why is it raised on legsabove the ground?

Why has it got louvredsides?


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Precipitation Rainfall, snow, hail and

fog.

Rainfall is measured in araingauge.

Some raingauges recordrainfall automatically

whilst others areemptied everyday by anobserver


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Wind

The direction and strength ofthe wind are both measured

Awind vanemeasures

direction An anemometerrecords

strength

Wind strength can also be

measured using the BeaufortScale


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Pressure

Pressure is the weight of theatmosphere

When air rises pressure falls

When air sinks pressureincreases

Pressure controls the type ofweather

Barometersandbarographsrecord pressure


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Recording pressure


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Sunshine A note is made of the

number of hours of

bright sunshine each day Sunshine is traditionally

measured using aCampbell-Stokes

sunshine recorder


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Cloud The amount of the sky

obscured by cloud

Different types of clouds

Sometimes even thespeed and direction in

which the clouds are

moving are recordedusing a nephoscope


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Cloud Types - Cumulus


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Cloud Types - Stratus


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Cloud Types - Cirrus


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The Hydrological Cycle

Module 1- Hydrological Cycle-1

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