Techniq es in Wate shed Management”

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M odu le 6 – ( L2 2 – L2 6 ) :

“

Use of M ode r n

Te ch n iq e s in W a t e sh e d M a n a ge m e n t ”

Te ch n iqu e s in W a t e r sh e d M a n a ge m e n t ”

Applica t ion s of Ge ogr a ph ica l I n for m a t ion Syst e m a n d Re m ot e Se n sin g in W a t e r sh e d M a n a ge m e n t , Role of g g , D e cision Su ppor t Syst e m in W a t e r sh e d M a n a ge m e n t

2 5

I n t e gr a t e d W a t e r sh e d M ode lin g Usin g N u m e r ica l M e t h ods GI S &

1 1 1 1

2 5

Usin g N u m e r ica l M e t h ods, GI S &

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L25

L25–

Integrated Watershed Modeling Using

l

h d

G S &

S

Numerical Methods, GIS & Remote Sensing



Topics Cove r e d



 Integrated watershed modeling; Numerical Integrated watershed modeling; Numerical

methods; Finite element method; Computer methods; Finite element method; Computer methods; Finite element method; Computer methods; Finite element method; Computer modeling; Geographical Information System; modeling; Geographical Information System; R i A li i i W h d R i A li i i W h d Remote sensing; Applications in Watershed Remote sensing; Applications in Watershed Management.

Management.



Keywords:

Integrated watershed modeling, numerical Integrated watershed modeling, numerical modeling; GIS; Remote sensing

modeling; GIS; Remote sensing..

2 2 2 2

modeling; GIS; Remote sensing modeling; GIS; Remote sensing..

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Necessity of Integrated Catchment/

Watershed Based Modeling

Water resources management- catchment/ watershed based

Watershed / catchment based- Watershed modeling-Planning & management

Catchment/ Rainfall – runoff Catchment/ Rainfall runoff

Modeling based on physical laws – Importance, necessity

An integrated catchment/ watershed model An integrated catchment/ watershed model. Hydrological Processes- Infiltration, Runoff, evaporation etc.

Digital revolution

 Recent advances in watershed modeling -Use of

numerical modeling, remote sensing and GIS.

3 3

g, g

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I n t e gr a t e d W a t e r sh e d M ode lin g Appr oa ch

I de n t ifica t ion of spe cific h ydr ologic pr oble m

D e sign s of GI S ( da t a la ye r s & a t t r ibu t e s) & RS D e sign s of GI S ( da t a la ye r s & a t t r ibu t e s) & RS

D a t a ba se bu ildin gg D a t a Pr oce ssin gg

Se le ct ion of h ydr ologic m ode l a n d for m u la t ion u sin g n u m e r ica l m e t h ods

M ode l com pu t a t ion s

4 4

Com pa r ison of r e su lt s

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Hydrologic/ Hydraulic Modeling

D iscu ssion

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Ph ysica lly Ba se d D ist r ibu t e d M ode ls

Rainfall

Channel phase flow

Ph ysica lly Ba se d D ist r ibu t e d M ode ls

Infiltration Infiltration

Overland flow

Rainfall

Fig. Flow in a watershed – Typical flow pattern

Flow at the Outlet of watershed Channel flow

Overland flow

Infiltration Infiltration

6 6

Fig. General concept of flow modeling

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Remote Sensing, GIS & Numerical Methods

 Re m ot e se n sin g

The remote sensing data are capable of solving the problem of scarcity of data.

Spatial variation Temporal variation

 Re m ot e se n sin g pr oce ss

1. Data acquisition 2. Data analysis

 Remote sensing - Capability of observing several

hydrological variables - Over large areas on titi b i

7 7

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Geographic Information Systems (GIS)

 Com pon e n t s of GI S

1. Data input data

2. Storage and management

3. Data manipulation and analysis 4 D t t t

4. Data output

System data storage and management and management

Data Manipulation

Data Input for p Data Output for and analysis

p system

User Interface - GUI

8 8 Prof. T I Eldho, Department of Civil Engineering, IIT Bombay

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Numerical Methods – Computer Models

 Conceptual modeling  Mathematical modeling

M h i l bl l d b

 Mathematical problems - solved by

arithmetical operations.

 Digital revolution- the role of numerical  Digital revolution- the role of numerical

methods

 Computer models – various modelsp

 Numerical methods

(a) finite difference method (b) finite element method

(c) finite volume method

9 9

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Selection of

Watershed Data collection _{for watershed} Mathematical formulation of model

Remotely Sensed data & GIS

Preparation of Thematic maps

Numerical Formulation GIS

Model development development

Testing and Evaluation of Model

Integrated Use of Numerical Method GIS & Finalization of model

10 10 Integrated Use of Numerical Method, GIS &

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Watershed Based Runoff modeling

fil i i d l

I nfiltration – Various models

Overland flow - One dimensional/ 2D

Channel flow - One dimensional

Component models coupled to get the runoff

Rainfall

Channel flow

Infiltration

O l d fl Overland flow

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I n filt r a t ion

Eg. Philip Infiltration Model: To calculate infiltration rate and subsequent excess rainfall

The rate of infiltration is given by

1 _{1 / 2}

1 2



 _i 

f s t K f potential infiltration rate i

s infiltration sorptivity

K hydraulic conductivity

1/ 2

Infiltration sorptivity K

3

 

 

s

K saturated hydraulic conductivity

ini

s _{initial (uniform) soil saturation degree}

 pore size distribution index

d diffusivity index ( )d  (1 2 ) / 

12 12

 saturated matrix potential of the soil

( ,d sini)

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Physically based Model

Governing equations for surface runoff

 Governing equations for surface runoff

1.Overland flow (Two dimensional) C ti it ti

a. Continuity equation

i

b. Momentum equation

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Physically based Model..







 (  )  0

2 Channel flow (One dimensional)





4₃

h

fy

3

h ( ) ( )

2.Channel flow (One dimensional)

a. Continuity equation

0

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Physically based Model…

b. Momentum equation





y

 Governing equation for ground water flow

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Gove r n in g e qu a t ion s for ove r la n d flow ( D iffu sion

q flow per unit width

h depth of flow

e

r _{excess rainfall intensity}

2 . M om e n t u m e qu a t ion

S _{slope of overland flow plane}

f

S _{friction slope of flow plane}

 Fin it e e le m e n t for m u la t ion - Ga le r k in ’s cr it e r ion is

u se d

  tt   t   _t _t __t   _t _t __t

 C h tt  C h t  t B (1)qt qtt t f (1)( )r_e t ( )r_e tt

F diff i d li

 is the factor that determines the type of finite difference scheme involved (0.5)

i i

For diffusion wave modeling

16 16

i and _k represent successive nodes in flow direction

L length of element

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 Gove r n in g e qu a t ion s for ch a n n e l flow

The equation of continuity



Q A

Q is discharge in the channel, A is area of flow in the channel,

Momentum equation

S is bed slope of channel

c

f

S is friction slope of channel

R is hydraulic radius ( A P/ ) P is wetted perimeter

n is channel flow Manning’s roughness coefficient  Fin it e e le m e n t for m u la t ion

For diffusion wave modeling

17 17

L

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Start

I t E i f ll f i filt ti d l d d ti N b d i f l t Input: Excess rainfall from infiltration model and duration, Number and size of elements, Roughness coefficients, Slopes, Bed width, Time step, Duration of simulation etc.

Initialization of variables

(Initialize nonzero depth at time t=0)

Calculation of element matrix for channel and overland flow

Generation of global matrix by assembling element matrices and applying boundary conditions for channel and overland flow

Solving the system for overland flow

If

Solving the system for channel flow

No

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M ode lin g Pr oce du r e

 Data collection for the selected watershed.  Mathematical modeling

 Mathematical modeling.

 Numerical formulation for the mathematical model.  Preparation of thematic maps of the watershed by

using

 Remote sensing imageries and GIS.

Development of software for the formulated model

 Development of software for the formulated model.  Testing and evaluation of the model for different

rainfall events

 Finalization of model.

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Modeling Procedure…

Discretization as rectangular strips

Channel network in

1 Overland flow

the watershed

Channel meeting

point 4

3

2 1

2

3

4

element node

Overland flow strip Single discretized channel with overland flow adding at channel nodes

W

4

L

Overland flow element

W L

20 20

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Example

Example ofof ChannelChannel flowflow modelmodel:: DiffusionDiffusion wavewave modelmodel ( Aral( Aral etet alal.. 1998

1998)) ..

Example

Length of each branch = 5,000 m; channel g , ; width is 50 m for two upstream channels & 100 m for d/s channel. Bed slope is 0.0002. Roughness coefficient is 0.025.

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Ca se St u dy:

Khadakhol Watershed

(V k R dd 2007) (Venkata Reddy, 2007)

Location- Nashik district, Maharashtra, India

E t L it d f 73 17' d 73 20' East Longitudes of 73o _{17' and 73}o _20'

North Latitudes of 20o _{07' and 20}o _09'.

Area- 5 89 km2

Area 5.89 km

Major soil class – Silty loam

Remotely sensed data- IRS 1D LISS III image Jan.13,1998 Thematic maps - Drainage, Slope and LU/LC, DEM

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Case Study: Rainfall –Runoff Modeling

 D a t a ba se pr e pa r a t ion

 Drainage m ap: Initially scanned topographical maps of the  Drainage m ap: Initially scanned topographical maps of the

area in 1:25000 scale are registered in ERDAS IMAGINE software. Watershed boundary and the drainage maps are digitized in ArcMap

digitized in ArcMap.

 Slope m ap: Contours with 10 m interval of the watershed

are digitized in ArcMap from topographical maps and Digital Elevation Model (DEM) with 100 m cell size has been

Elevation Model (DEM) with 100 m cell size has been generated using TOPOGRID option of ArcInfo software.

 LU/ LC m ap: Remotely sensed data of IRS 1D LISS III path

105 and row 55 of January 13 1998 has been used to 105 and row 55 of January 13, 1998 has been used to

extract LU/ LC of the watershed. LU/LC map is derived from remotely sensed data of watershed by supervised

classification using ERDAS IMAGINE software

23 23

classification using ERDAS IMAGINE software

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Land Use/Land Cover map

False Colour Composite p

False Colour Composite

Kh a da k oh ol W a t e r sh e d

Digital Elevation Model map

24 24

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8

August 23 1997

5

6 0

10

i f ll

August 23, 1997

1

ainfall Intensity

(mm/hr)

Finite element grid map

Observed and Simulated hydrographs

August 22, 1997

25 25

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Integrated Modeling – Concluding Remarks

 The digital revolution.

R t d t i d GIS

 Recent advances -remote sensing and GIS

technologies.

Use of remote sensing and GIS in watershed

 Use of remote sensing and GIS in watershed

modeling.

 Use of Distributed / Lumped models  Use of Distributed / Lumped models  Hydrologic/ Hydraulic Modeling – By

Numerical methods Numerical methods

 Integrated models – Remote Sensing, GIS &

Hydrologic Models

26 26

y g

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Re fe r e n ce s

• Raj Vir Singh (2000), Watershed Planning and Management, Yash Publishing House

• J.V.S Murthy (1991), Watershed Management, New Age international y ( ), g , g Publications

 Venkata Reddy K., Eldho T. I., Rao E.P. and Hengade N. (2007) “A

kinematic wave based distributed watershed model using FEM, GIS and t l d d t ” J l f H d l i l P 21 2765

remotely sensed data.” Journal of Hydrological Processes, 21, 2765-2777

 Chow, V.T., Maidment, D.R., and Mays, L.W. (1988). Applied

Hydrology McGraw-Hill Inc New York

Hydrology, McGraw Hill, Inc., New York.

 Bedient, P.B. and Huber W.C.(1988). Hydrology and flood plain

analysis, Addison-Wesley Publishing Company., London.

 Cunderlik, J. M. (2003). “Hydrologic model selection for the CFCAS  Cunderlik, J. M. (2003). Hydrologic model selection for the CFCAS

project: Assessment of Water Resources Risk and Vulnerability to changing Climatic Conditions – Project Report 1”, Department of Civil and Environmental engineering, University of Western Ontario

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Tu t or ia ls - Qu e st ion !.?.

 Critically study the necessity of integrated

approach of watershed modeling using approach of watershed modeling using numerical methods, GIS and remote sensing. Study various case studies g y available in literature (details can be obtained from Internet).



 Study the role of integrated watershed Study the role of integrated watershed

modeling in Integrated Water Resources modeling in Integrated Water Resources Management

Management.

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Se lf Eva lu a t ion - Qu e st ion s!.

Q

 Describe the necessity of Integrated Watershed

b d d li

based modeling.

 Explain the step by step methodology in use of

i l d l GIS d t i f

numerical models, GIS and remote sensing for watershed based modeling

Diff ti t b t d i / diff i

 Differentiate between dynamic wave/ diffusion

wave/ kinematic wave based physical modeling for rainfall runoff modeling of watersheds

for rainfall-runoff modeling of watersheds.

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Assign m e n t - Qu e st ion s?.

g

Q

 Illustrate how GIS & remote sensing can

help in effective watershed modeling in p g combination with numerical modeling.

 For physically event based rainfall runoff

modeling, illustrate various hydrologic

processes to be considered in the modeling. f

 In integrated approach of watershed

modeling, describe the modeling procedure.

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Un solve d Pr oble m !.



 For your watershed area, study the scope of integrated For your watershed area, study the scope of integrated

modeling for rainfall

modeling for rainfall--runoff using numerical models, GIS gg runoff using numerical models, GIS gg and remote sensing. Remote sensing for the watershed and remote sensing. Remote sensing for the watershed area may be obtained from ASTER

area may be obtained from ASTER

((http://asterweb.jpl.nasa.gov/http://asterweb.jpl.nasa.gov/)/ SRTM )/ SRTM

((http://srtm.usgs.gov/index.phphttp://srtm.usgs.gov/index.php) / BHUVAN/ IRS ) / BHUVAN/ IRS ((http://bhuvan.nrsc.gov.in/bhuvan_links.htmlhttp://bhuvan.nrsc.gov.in/bhuvan_links.html) )



 Hydrological model may be obtained from HECHydrological model may be obtained from HEC--RAS, HECRAS,

HEC--HMS software:

HMS software: w w w .w w w .h e ch e c_{.usace.arm y.m il/ soft ware/}_{.usace.arm y.m il/ soft ware/}h e ch e c --h m s

h m s

 For the average/ maximum/ minimum rainfall pattern in

the watershed area, asses the runoff for the watershed.

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Dr. T. I. Eldho Dr. T. I. Eldho Professor,

Professor,

Department of Civil Engineering, Department of Civil Engineering, pp gg gg

Indian Institute of Technology Bombay, Indian Institute of Technology Bombay, Mumbai, India, 400 076.

Mumbai, India, 400 076.

Email:

Email: eldho@iitb.ac.ineldho@iitb.ac.in

32 32

Email:

Email: eldho@iitb.ac.ineldho@iitb.ac.in

Phone: (022)

Phone: (022) –– 25767339; Fax: 2576730225767339; Fax: 25767302 http://www.