Surface Water and Groundwater Interaction Modelling

Water Resources System Research Unit, Chulalongkorn University, ThailandDepartment of Geotechnology and Geohydraulics, University of Kassel, Germany

Werapol BejranondaProf. Manfred KochAssoc.Prof. Sucharit Koontanakulvong

2

ContentsContents Introduction

Study Area Application

Methodology Modeling Results

Introductionstudy area

Source: RID 3rd regional bureau

Existing irrigation projects and its supplies by reservoirs

Nan river

Yom river Study area

Sukkhothai

Phichit

Phitsanulok

Division 1

Division 2

Division 3Thailand

Study area : Plaichumpol Irrigation Project

Introductionstudy approach

Overview of SW-GW interaction

Saturated Zone

GW Pumping

River/Canal

Surface water

Rainfall

Irrigationsupply

Objectives

GW use GW flow model

irrigation water water shortage

agriculturaldemand in

irrigation area

GWpotential

conjunctive use

applicability

focused on water use and allocation in an irrigation area from both canals and local shallow wells.

study water use patterns and interaction between surface water and groundwater

determining the potential of conjunctive use

Applicationmethodology

1

2

Data collection(SW-GW)Existing monitoring well : 35 wells

New-installed well : 2 wells(to investigatestream-groundwater interaction)

Groundwater Level Monitoring

Infiltration Test

10 points varied with soil types(to investigatesurface recharge)

Stream Stages

Over view of field data collection

Canal Stage (at check gate)

Saturated Zone

Observed Wells

Bed Materials

Infiltration Test

50 m. 200 m.

ApplicationGW modeling

Upper aquifer - Semi-confined

Lower aquifer – Confined200-300

m.

40-100 m.

Upper aquiferUpper aquifer ((Qfd and Qlt)Qfd and Qlt)

Lower Lower aquiferaquifer ((Qht)Qht)

Conceptual Model

MODFLOW500 m. x 200 m. grid-cells

1993 2005 2035Model calibratio

n

GW potential investigat

ion

Calibration & Verification

GW potential Investigation

-

5

10

15

20

25

јҖѥь

Dry/Wet Year

дѥіѲн

ҖьѸѼѥэѥчѥј(ј

Җѥьјэ.

є./

њѤь)

ѲнҖьѸѼѥэѥчѥј іњєнѤѸььѸѼѥѝҕњьэьнѤѸььѸѼѥѝҕњьј ҕѥк

Demand projection

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юҍ

іѣч

ѤэьѸѼѥ

(є.і

ъд.)

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GW use variationobs. gw level during simulation

GW ModelBoundariesand Sources/Sinks

River Source/Sink

Head Boundaries

Head Source/Sink(Pond)

FlowBoundaries

GW ModelBoundariesand Sources/Sinks

Head Boundaries

FlowBoundaries

River Sources

GW table away from Main Irriagtation Cannal

Groundwater Level

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-2 -1.8 -1.6 -1.4 -1.2 -1 -0.8 -0.6 -0.4 -0.2 0

і ѣѕѣўҕѥклѥдзј ѠкѝҕкьѸѼѥѝѥѕѲўр ҕ(дє.)

іѣчѤэьѸѼѥэ

ѥчѥј

(є.і

ъд)

зј ѠкѝҕкьѸѼѥѝѥѕўј Ѥд

шѣњѤьѠѠдшѣњѤьшд

distance form main irrigation canal (km)

main irrigationcanal

Applicationresults

Upper Aquifer(Δstorage = -34.6 )

103.6Lateral outflow

69.8Lateral inflow

0.004Leak to lower aquifers

9.2GW pump

1.3River-Aquifer interaction7.1

Recharge

Upper Aquifer(Δstorage = -3.3 )

10.9Lateral out flow

18.4Lateral inflow

0.001Leak from lower aquifers

13.2GW pump

Unit : million m3/month

1.6River-Aquifer interact.0.9

RechargeDry season

Wet season

Sukkhothai

Phichit

Phitsanulok

Division 1

Division 2

Division 3

irrigationdivision

gw use 2007(mil.m3/year)

gw potential(mil.m3/year)

use/potential

1 25.2 41.9 60%60%

2 60.6 221.5 27%27%

3 57.2 66.4 86%86%

Total 143.1 329.8 43%43%

water situation

amount (million cubic meter) percentage to irrigation demand

Irrigation demand

act. surface water

supply

groundw. extraction

planed demand

act. surface water

supply

groundw. extraction

wet 275 135 74 100% 49% 27%

normal 268 86 96 100% 32% 36%

dry 300 141 156 100% 47% 52%

drought 266 167 181 100% 63% 68%

Groundwater potential

Average conjunctive water useand their ratios during the dry season

guideline for conjunctive-use planning in case of normal water situation at the Plaichumpol Irrigation Project

non-irrigation0 – 25 %25 – 50 %50 – 140 %

groundwater use ratio(percentage of irrigation supply)

riverIrrigation canal

-20

-15

-10

-5

0

1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007

Gro

undw

ater

lev

el(m

. bel

ow g

roun

d su

rfac

)

calculated PCP-01calculated PCP-19calculated PCP-12obs PCP-01obs PCP-19obs PCP-12

PCP-01

PCP-12

PCP-19

Computed groundwater levelvaried with season in 1997-2007

PCP-12

PCP-19

mainirrigation canal

PCP-01

Questions & Answers

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