Modified Correlation Techniq Case Study Munda Dam S.M. Saeed Shah

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Modified Correlation Technique for Simulation of Long-Term Inflows Time Series

13

Modified Correlation Technique for Simulation of Long-TermInflows Time Series (A Case Study of Munda Multipurpose Dam Project)

S. M. Saeed Shah*, Muhammad Kaleem Sarwar **

and Sohail Saleem***

ABSTRACT

Munda Multi purpose Dam Project is runof f ri ver hydropower project on Swat ri ver

near Munda headwork. The study aimed to generate the long term in fl ow time ser ies

for the planning of Munda Mult ipur pose dam project. Data coll ected for th is study

includes rainfall , stream flow, ri ver diversions, etc. I t was dif f icul t to update the

isohyets of the area because of unavailability of the data required for makingisohyets. Instead of regional analysis as done in the previous studies, the modif ied

correlati on techni que was developed employing the shor t duration avail able data.

For this development, the major sub-catchments were included which were not

considered in the previous studies. Short term data of Zulam Br idge and M unda site

was extended from 1956 to 1990, as a case study.

As an outcome of the study, the expected in flows to the Munda dam reservoir

were simulated whi ch extended inf lows avail able from previous reports. Ef for t was

really beneficial for the plann ing of dam and i ts appurtenant structur es.

Key-words: Headworks, Mul tipurpose dam, River diversion, Modif ied Co-relation

1. INTRODUCTION

HE water strategy prepared by

Government of Pakistan calls for a

rational approach to develop the newresources employing the efficient

management of existing supplies. The options

for new resources, through additional storage,have been controversial and require an indepth analysis as part of an integrated

approach. Munda Multipurpose Dam Project

may be regarding as good Hydropower project, to get the maximum benefits from the

project, the study was conducted through

conservative and precise mode by keeping in

view the pros and cons of the respective site

and it’s surrounding. The estimation ofreservoir inflows has been done using the

correlation method established between the

sub- basins having similar meteorological andtopographic characteristics, to enable the planner to be precise in reservoir capacity and

other allied parameters. Figures 1 and 2

show, respectively, the location map andgauging stations of Munda multi-purpose

dam and swat river basin.

*Head of Hydrology Division, **Lecturer, ***Research Scholar, Centre of Excellence in Water Resources

Engineering, University of Engineering & Technology, Lahore, Pakistan.

Correspondence to: M. Kaleem Sarwar, Centre of Excellence in Water Resources Engineering, University

of Engineering and Technology, G.T. Road, Lahore-54890, Pakistan. E-mail: [email protected]

T

Science, Technology & DevelopmentVol. 30, No. 3 (July-September) 2011

mailto:[email protected]

mailto:[email protected]



Science, Technology & Development – Vol. 30, No. 3 (July-September) 2011

14

Figure 1: Location Map of Swat River Basin



Modified Correlation Te

Figure 2: Irrigation S

chnique for Simulation of Long-Term Inflows Time Series

15

heme of Swat River Basin with Gauging Stati ns




16

NESPAK (1993) estimated the reservoirinflows on the basis of regional analysis and flowdata observed at Munda Headworks. The meanannual inflows at Munda Dam site by gauged data

and regional analysis are 255.6 m3/s and 239 m3/srespectively. Nippon Koei (2000) reviewed theestimates made by NESPAK and assessed the

inflow value of 206.2 m3

/s for Munda Dam site.Falkland (1991) indicated that when surface

records are unavailable or if records are missing,surface runoff can be estimated by mostcommonly used correlation method. Chow (1964)

pointed out that one must assume while usingrational formula that maximum rate of flow due

to certain rainfall intensity over the drainage areais produced which is maintained for a time equal

to the period of concentration at the point underconsideration. Shaw (1988) showed that rainfallrunoff relationship depends upon climatic and

catchment conditions of the area. Singh andsomkid (1977) compared the four methods

including the Phi index, Horton equation,Kostiakov and Philip method to predict surfacerunoff from two natural agricultural watersheds.Mutreja (1986) noted that runoff in a regiondepends upon rainfall input, physical, vegetation

and climatic characteristics of the region. Awan(1986) observed the runoff for Baran Dam bymeasuring the time to peak, peak discharge andstorm duration.

2. OBJECTIVES OF STUDYThe objectives of this study includes the

1. Extension of flow series from 1956 to2005 using correlation technique.

2. Assessment of inflows for Munda Damreservoir.

3. METHODOLOGY

3.1 Plausibility and Consistency Tests

The observed records of the new streamgauges at Munda dam site and Zulam Bridgewere tested for the consistency with the

concurrent records of other stations. Whilescrutinizing the daily flow series of Zulam

Bridge, an anomaly was detected in its daily timeseries starting from 30 June to 28 August 2000that were caused by using an incorrect (old) flow

rating equation. The flow-values were, therefore,adjusted. According to WMO (1974), if a short

record is to be used in design, it can be extendedto a longer period by correlating the monthlyflows with the concurrent monthly-flows at along-term station. Unless the coefficient of

correlation (R 2) is greater than 0.8, extension/adjustment is usually not worth the effort.

Linear regression analysis was carried out

between the naturalized monthly flows of ZulamBr. and Chackdara minus Kalam for each month

for the concurrent period of record.

Q zulam Br. Vs Q chakdara – Q kalam

Linear regression analysis was conducted between naturalized monthly flows of ZulamBridge plus Chakdara and Munda dam site, forthe concurrent period of record (April 1999 to

March 2005). The monthly regression curves areillustrated in Figures 7 & 8. Regression

coefficients, R

2

for January through Novemberare satisfactory, being greater than 0.8 but is 0.76for December.

Q Munda Vs Q Zulam Br. + Q chakdara

3.2 Reviewing and Updating the Rainfall and

Flow Data

Rainfall records of the 8 rain gauges, Abazai,Charbagh, Dir, Kalam, Karora, Malakand,

Totakhan and Zulam Bridge, have been used inThiessen’s polygons to compute areal rainfall ofindividual sub-basins. Peshawar, Utmanzai and

Mardan have little or no influence on the rainfallof the sub-basins, being considerably outside the

catchment area. Amandara and Totakhan are veryclose to each other. Kalangi and Saidu Sharifhave short period records. Hence, the rainfall-data

of these 6 gauges (Peshawar, Utmanzai, Mardan,Amandara, Kalangi and Saidu Sharif) have not

been used. Mean monthly rainfall values ofvarious rain gauges in the study area, for uptoMarch 1999 period and April 1999 to March 2005

period are summarized in Table 1.

Mean annual rainfall at most of the stations is

greater in upto March 1999 period than that in theApril 1999 to March 2005 period. Hence thelatter period was evidently a dry period. So arealrainfall amount of summer (Apr-Sep) and winter

(Oct-Mar) seasons were computed for Swat andPanjkora river sub-basins by using Thiessen’s

polygons and their bar graphs drawn in Figures 3and 4 for the two sub-basins.




17

Table 1: Summary of Mean Annual Rainfall (mm)

Gauging Stations Period of Recorded

Data Up to March

1999 April 1999 to

March 2005

Abazai 1961-2005 514 489

Amandara 1961-2005 650 821

Charbagh 1961-2005 1005 763

Dir 1990-2005 1544 1201

Kalam 1962-2005 942 947

Karora 1974-2005 1374 1251

Malakand 1961-2005 801 701

Totakhan 1974-2005 724 513

Utmanzai 1964-2005 515 439

Zulam Br. 2000-2005 - 774

Figure 3: Seasonal Annual Rainfall of Swat Sub Basin

0

200

400

600

800

1000

1200

1400

1600

1 9 7 4 - 7 5

1 9 7 5 - 7 6

1 9 7 6 - 7 7

1 9 7 7 - 7 8

1 9 7 8 - 7 9

1 9 7 9 - 8 0

1 9 8 0 - 8 1

1 9 8 1 - 8 2

1 9 8 2 - 8 3

1 9 8 3 - 8 4

1 9 8 4 - 8 5

1 9 8 5 - 8 6

1 9 8 6 - 8 7

1 9 8 7 - 8 8

1 9 8 8 - 8 9

1 9 8 9 - 9 0

1 9 9 0 - 9 1

1 9 9 1 - 9 2

1 9 9 2 - 9 3

1 9 9 3 - 9 4

1 9 9 4 - 9 5

1 9 9 5 - 9 6

1 9 9 6 - 9 7

1 9 9 7 - 9 8

1 9 9 8 - 9 9

1 9 9 9 - 0 0

2 0 0 0 - 0 1

2 0 0 1 - 0 2

2 0 0 2 - 0 3

2 0 0 3 - 0 4

2 0 0 4 - 0 5

Year

S e a s o n a l R a i n f a l l (

m m )

Apr. - Sep Rainfall

Oct - Mar. Rainfall

Annual

Average Apr. - Sep.

Average Oct. - Mar.

Annual Average

Average=530

Average =486

Annual Average = 1016




18

Figure 4: Seasonal Annual Rainfall of Panjkora Sub Basin

The bar graphs as shown in figures 3 and 4

for seasonal Rainfall reveal that:• Rainfall was below average during the period

of April 1999 to March 2005, especially in

Panjkora sub-basin;

• Several low-rainfall years were followed by

high-rainfall years;

• In very few cases, October-March is low

rainfall period but overall there is highrainfall in Oct-March as compared to Apr-Sep. period.

• Average annual rainfall amounts over

Panjkora and Swat sub-basins for post – 1999 period are 983 mm and 951 mm respectively(slightly higher on Panjkora sub-basin) butaverage annual runoff is 103.7 m3/s at ZulamBridge on the Panjkora river and 153.8 m3/s

at Chakdara on the Swat river, for the same period. It is interesting to note that runoff at both stations are roughly equal from October

to April. In fact, March runoff is slightly

greater at Zulam Br. than at Chakdara. Butfrom May to September, Chakdara flows are

much greater than those at Zulam Br. Thisimplies that the Swat river flows are

dominated by snow-melt but the Panjkorariver is not.

The bar graph of the daily flows (cumecs) of

Munda dam site and that of Zulam Bridge for the period April 1999 – March 2005 is shown in

Fig.5(a-b). Generally, flows at Munda dam siteare larger than those at Zulam Br. except on 1

st

March 2000 that is probably due to rather poor

fitting of flow rating equation at the lowest limbof the curve. However, its impact is insignificant

on the result. Double-mass curve of the monthlyflow volumes at Zulam Bridge versus those atKalam + Chakdara + Munda dam site is shown inFig. 6. It reveals some minor departure from astraight line, probably due to shifting of bed at

very high flows.

0

200

400

600

800

1000

1200

1400

1600

1800

1 9 9 0 - 9 1

1 9 9 1 - 9 2

1 9 9 2 - 9 3

1 9 9 3 - 9 4

1 9 9 4 - 9 5

1 9 9 5 - 9 6

1 9 9 6 - 9 7

1 9 9 7 - 9 8

1 9 9 8 - 9 9

1 9 9 9 - 0 0

2 0 0 0 - 0 1

2 0 0 1 - 0 2

2 0 0 2 - 0 3

2 0 0 3 - 0 4

2 0 0 4 - 0 5

Year

S e a s o n a l R a i n f a l l ( m m )

Apr. - Sep Rainfall

Oct - Mar. Rainfall

Annual

Average Apr. - Sep.

Average Oct. - Mar.

Annual Average

Average=613

Average =554

Annual Average = 1168




19

Figure 5(a): Daily Flows Bar Graphs for Munda Dam vs. Zalum Bridge (Apr. 99 – Mar. 02)

Figure 5(b): Daily Flows Bar Graphs for Munda dam vs. Zalum Bridge (Apr. 02 - Mar. 05)

0.0

100.0

200.0

300.0

400.0

500.0

600.0

700.0

1 - A p r - 9 9

1 - M a y - 9 9

1 - J u n - 9 9

1 - J u l - 9 9

1 - A u g - 9 9

1 - S e p - 9 9

1 - O c t - 9 9

1 - N o v - 9 9

1 - D e c - 9 9

1 - J a n - 0 0

1 - F e b - 0 0

1 - M a r - 0 0

1 - A p r - 0 0

1 - M a y - 0 0

1 - J u n - 0 0

1 - J u l - 0 0

1 - A u g - 0 0

1 - S e p - 0 0

1 - O c t - 0 0

1 - N o v - 0 0

1 - D e c - 0 0

1 - J a n - 0 1

1 - F e b - 0 1

1 - M a r - 0 1

1 - A p r - 0 1

1 - M a y - 0 1

1 - J u n - 0 1

1 - J u l - 0 1

1 - A u g - 0 1

1 - S e p - 0 1

1 - O c t - 0 1

1 - N o v - 0 1

1 - D e c - 0 1

1 - J a n - 0 2

1 - F e b - 0 2

1 - M a r - 0 2

M e a n D a i l y F l o w s ( c u m e c s ) - M

u n d a S i t e

Munda

Zulam

M e a n D a i l y F l o w s ( c u m e c s ) - Z

u l a m B

r .

0.0

100.0

200.0

300.0

400.0

500.0

600.0

700.0

800.0

1 - A p r - 0 2

1 - M a y - 0 2

1 - J u n - 0 2

1 - J u l - 0 2

1 - A u g - 0 2

1 - S e p - 0 2

1 - O c t - 0 2

1 - N o v - 0 2

1 - D e c - 0 2

1 - J a n - 0 3

1 - F e b - 0 3

1 - M a r - 0 3

1 - A p r - 0 3

1 - M a y - 0 3

1 - J u n - 0 3

1 - J u l - 0 3

1 - A u g - 0 3

1 - S e p - 0 3

1 - O c t - 0 3

1 - N o v - 0 3

1 - D e c - 0 3

1 - J a n - 0 4

1 - F e b - 0 4

1 - M a r - 0 4

1 - A p r - 0 4

1 - M a y - 0 4

1 - J u n - 0 4

1 - J u l - 0 4

1 - A u g - 0 4

1 - S e p - 0 4

1 - O c t - 0 4

1 - N o v - 0 4

1 - D e c - 0 4

1 - J a n - 0 5

1 - F e b - 0 5

1 - M a r - 0 5 M

e a n D a i l y F l o w s ( c u m e c s ) - M u n d a

S i t e

MundaZulam

M e a n D a i l y F l o w s ( c u m e c s ) - Z u l a m B

r .




20

Figure 6: Double Mass Curve of Monthly Flows (April 99 - March 2005)

4. RESULTS AND DISCUSSIONS

4.1 Extension of River Flows at Zulam Bridge

The analysis of flow and rainfall recordsindicates no direct overall relationship betweenrainfall and runoff on an annual or monthly basis

as flows of this area depend in most of the caseson snowmelt runoff. The average annual runoff

coefficients at Kalam and Chakdara were

estimated at 1.5 and 1.1 respectively. Theseunrealistic coefficients cannot be used to generate

runoff from rainfall because heavy snowfall in theupper basin of the Swat and Panjkora rivers arenot recorded. Therefore, the application of arainfall-runoff type hydrologic model to estimateriver flows would be misleading.

A new stream flow measuring station wasestablished at Zulam Bridge on the Panjkora river

in March 1999 and a staff gauge was installed totake hourly observation of gauge heights from 8a.m. to 4 p.m. daily. The data were collected and

compiled from April 1999 to March 2005.Monthly stream flow data of the Swat river at

Kalam and Chakdara are available from January

1956 to March 2005. Drainage areas of thePanjkora river at Zulam Br. and the Swat river at

Kalam and Chakdara are 5793, 2020 and 5770km2 respectively. Upstream of Chakdara, 3

irrigation canals (Fatehpur, Nipkikhel andBadwan Kharif) have been abstracting 2.72 m3/sannually in the past and about 4.60 m3/s

presently. Similarly, Darora and Ganidigar canals

y = 0.2001x + 10.649

R 2 = 0.9985

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

0 5,000 10,000 15,000 20,000 25,000 30,000 35,000

Munda + Chakdara + Kalam (MCM)

Z u l a m B

r .

( M

C M

)




21

were abstracting 1.92 m3/s annually in the pastand 2.21 m

3/s presently from Panjkora river.

There is no irrigation canal upstream of Kalamgauge. These data are of great value, enabling the

synthesis of historic monthly flows of thePanjkora river at Zulam Bridge, through linearcorrelation with flows at Kalam and Chakdara.

4.2 Basis of Correlation

The assessment of record for longer periodwas done in accordance with the WMO’s Guideto Hydrological Practices (WMO, 1974).Physiography and meteorology of the Panjkora

and Swat river sub-basins are similar. Both arehilly areas and adjacent to each other. Upper

parts of both sub-basins have high annual rainfall.Dir in Panjkora river sub-basin has 1410 mm of

annual rainfall and Karora in Swat river sub-basinhas 1346 mm of annual rainfall. Lower parts of

both sub-basins have rather low annual rainfall.However, the upper part of the Swat sub-basin isalmost completely covered by snow during winter

and hence snowmelt contribution during summeris substantial. This is not the case with Panjkorasub-basin which generates significantly less

snowmelt. This is reflected by a high runoff depth(838 mm) from Chakdara catchment as comparedto runoff depth (564 mm) from Zulam Bridgecatchment. Hence the correlation between Zulam

Bridge and Chakdara might be questionable. IfKalam flows are subtracted from Chakdara flows,the impact of snowmelt is significantly reduced

and the similarity between Panjkora and Swatsub-basins below Kalam improves appreciably.

Hence monthly flows at Zulam Bridge werecorrelated with flows generated between Kalamand Chakdara, Fig.7.The idea of correlating therainfall and runoff of the two sub basins wasconceived from Falkland (1991), Mutreja (1986)

and Shaw (1988).

Adding irrigation abstractions upstream of the

gauging station has naturalized the flows.Monthly flows of Chakdara (naturalized) minusKalam were calculated, for April 1999 – March

2005 period. The observed and naturalized annualflows at different gauges are summarized in

Table 2.

Table 2: Summary of Mean Annual Flows

Period 1956–Mar 1999 Apr.1999–Mar 2005 1956–Mar 2005

Observed Flows(m3/s)

Kalam 91.0 77.4 89.4

Chakdara 182.6 153.7 179.1

Munda Site 216.4

Zulam Bridge 101.8

Naturalized Flows(m /s)

Chakdara 182.6 153.8 179.0

Munda Site 280.8

Zulam Bridge 103.8




22

April

y = 1.0332x + 73.046R

2 = 0.9613

50.0

75.0

100.0

125.0

150.0

175.0

200.0

225.0

250.0

275.0

300.0

0.0 50.0 100.0 150.0 200.0 250.0(d) Mean Monthly Flows at Chakdara-Kalam

M e a n M o n t h l y F l o w s a t Z u l a m B

r .

March

y = 1.5079x + 17.03

R2 = 0.9854

0.0

50.0

100.0

150.0

200.0

250.0

300.0

350.0

400.0

450.0

500.0

0.0 50.0 100.0 150.0 200.0 250.0 300.0

(c)Mean Monthly Flows at Chakdara-Kalam


r .

June

y = 1.2101x + 22.293

R2 = 0.8588

75.0

95.0

115.0

135.0

155.0

175.0

195.0

215.0

235.0

255.0

50.0 70.0 90.0 110.0 130.0 150.0 170.0 190.0 210.0

(f) Mean Monthly Flows at Chakdara-Kalam


r .

May

y = 0.8633x + 88.629

R2 = 0.971

100.0

115.0

130.0

145.0

160.0

175.0

190.0

205.0

220.0

235.0

250.0

265.0

75.0 105.0 135.0 165.0 195.0 225.0

(e) Mean Monthly Flows at Chakdara-Kalam


r .

January

y = 0.9986x + 12.05

R2 = 0.93

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

0.0 20.0 40.0 60.0 80.0

(a) M ean M onthly Flows at Chakdara-Kalam

February

y = 0.5165x + 40.177

R2 = 0.9626

0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

0.0 50.0 100.0 150.0 200.0

(b) M ean M onthly Flows at Chakdara-Kalam




23

Fig.7: Monthly correlation between Zulam Br. and Chakdara minus Kalam

August

y = 1.1971x - 39.81

R2 = 0.3817

0.0

25.0

50.0

75.0

100.0

125.0

150.0

175.0

200.0

225.0

50.0 70.0 90.0 110.0 130.0 150.0

(h) M ean M onthly Flows at Chakdara-Kalam

July

y = -0.1112x + 128.4

R2 = 0.0074

50.0

70.0

90.0

110.0

130.0

150.0

170.0

190.0

0.0 50.0 100.0 150.0 200.0

(g) M ean M onthly Flows at Chakdara-Kalam

October

y = 1.6436x + 0.4455

R2 = 0.883

0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

160.0

180.0

0.0 20.0 40.0 60.0 80.0 100.0

(j) Mean Monthly Flows at Chakdara-Kalam


r .

September

y = -0.0927x + 57.672

R2 = 0.0969

40.0

50.0

60.0

70.0

80.0

90.0

100.0

0.0 20.0 40.0 60.0 80.0 100.0

(i) Mean Monthly Flows at Chakdara-Kalam

November

y = 2.1386x - 11.058

R2 = 0.5144

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

10.0 15.0 20.0 25.0 30.0 35.0 40.0

(k) Mean Monthly Flows at Chakdara-Kalam

M e a n

M o n t h l y F l o w s a t Z u l a m B

r .

December

y = -0.9226x + 53.89

R2 = 0.3333

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0

(l) Mean Monthly Flows at Chakdara-Kalam


r .




24

Mean annual rainfall values at Dir compiledin Table 3 for pre and post 1999 periods indicatesthat April 1999 – March 2005 was a dry periodfor the Panjkora river sub-basin consequently less

flows occur at Zalum Bridge for the same period

Table 3: Mean Annual Rainfall Values at Dir

Period Mean Annual Rainfall(mm)

Jan 1990 – Mar 1999 1544

Apr 1999 – Mar 2005 1201

4.3 Synthesized Flows at Zulam Bridge

Linear regression analysis was carried

between the naturalized monthly flows of ZulamBr. and Chakdara minus Kalam for each month

for the concurrent period of record. Results of theregression analysis are depicted in Table 4 andillustrated in Figure 7. The regression coefficients(R 2) for January through June and October are

satisfactory, but for the remaining months (Julythrough September, November and December) isunsatisfactory being less than 0.8. For these

months, arithmetic ratios of corresponding flowsat Zulam Br. and Chakdara minus Kalam is

considered more appropriate for reconstitution offlows at Zulam Bridge. The monthly ratios aregiven in Table 5. Synthesized flows at Zulam Br.for the period January 1956 – March 1999. Themean annual flow (naturalized) is 121.9 m3/sec

and after irrigation subtractions is 119.9 m3/sec.

Table 4: Linear Regression between Monthly Flows of Zulam Br. and Chakdara Minus Kalam

Month Equation Between Zulam Br. & Chakdara – Kalam.

Reg. Coeff. R 2

Remarks

Jan QZ = 0.9986 QCl + 12.05 0.93 Satisfactory

Feb QZ = 0.5165 QCl + 40.18 0.96 Satisfactory

Mar QZ = 1.5079 QCl + 17.03 0.99 Satisfactory

Apr QZ = 1.0332 QCl + 73.046 0.96 Satisfactory

May QZ = 0.8633 QCl + 88.63 0.97 Satisfactory

Jun QZ = 1.2101 QCl + 22.29 0.86 Satisfactory

Jul QZ = -0.1112 QCl + 128.4 0.01 Unsatisfactory

Aug QZ = 1.1971 QCl – 39.81 0.38 Unsatisfactory Sep QZ = -0.0927 QCl + 57.672 0.097 Unsatisfactory

Oct QZ = 1.6436 QCl + 0.4455 0.88 Satisfactory

Nov QZ = 2.1386 QCl – 11.06 0.51 Unsatisfactory

Dec QZ = -0.9226 QCl + 53.89 0.33 Unsatisfactory

Table 5: Monthly Ratios between Flows at Zulam Br. and Chakdara minus Kalam

Month Average Monthly Flows(m

3/sec)

Monthly Flow Ratios

Zalum Bridge Chakdara-Kalam

July 111.90 122.60 0.910

August 109.00 105.20 1.040

September 64.50 50.30 1.280

November 46.60 26.50 1.760

December 38.80 19.20 2.020




25

4.4 Estimation of River Flows at Munda Dam Site Following seven steps used in establishing a

long record of river flows at the Munda dam site:

(i) First combined (naturalized) monthly flows atZulam Bridge and Chakdara were computedfor April 1999 – March 2005 period. For theconcurrent period, monthly flows at Mundadam site were naturalized in Table 2, by

adding corresponding historic monthlydiversions into various canals upstream of theMunda dam site.

Q Munda = Q Munda + Irrigation Diversions

It is noted that 23.7m3/sec (747.4 MCM) of

mean annual flow was generated in the lowersub-basin downstream of Chakdara and

Zulam Br. during April 1999 – March 2005 period. This is about 289 mm of annualrunoff depth from 2584 km2 of drainage area.The annual areal rainfall amounts of

Ambahar and incremental sub-basins are 491mm and 569 mm respectively. Thereforerunoff-rainfall coefficient (between 0.4 and

0.5) of these lower sub-basins appearssatisfactory.

(ii) Linear regression analysis was conducted between naturalized monthly flows of ZulamBridge plus Chakdara and Munda dam site,

for the concurrent period of record (April1999 to March 2005). The monthly regression

curves are illustrated in Fig. 8.

y = 0.9013x + 14.313

R² = 0.933

0.0

40.0

80.0

120.0

160.0

200.0

0.0 50.0 100.0 150.0 200.0

M u n d a D a m S

i t e

(a) Chakdara + Zulam Br.

January

y = 0.8492x + 26.81

R² = 0.8854

0.0

50.0

100.0

150.0

200.0

250.0

300.0

0.0 100.0 200.0 300.0 400.0

M u n d a D a m S

i t e

(b) Chakdara + Zulam Br.

February

y = 0.7959x + 53.735R² = 0.9818

0.0

100.0

200.0

300.0

400.0

500.0

600.0

700.0

0.0 200.0 400.0 600.0 800.0

M

u n d a D a m S

i t e

(c) Chakdara + Zulam Br.

March

y = 1.3041x - 38.787R² = 0.9688

0.0

100.0

200.0

300.0

400.0

500.0

600.0

700.0

0.0 100.0 200.0 300.0 400.0 500.0 600.0

M

u n d a D a m S

i t e

(d) Chakdara + Zulam Br.

April




26

Fig.8: Monthly Correlation between Munda vs Chakdara plus Zulam Br.

May

y = 1.2533x - 72.186

R2 = 0.8762

0.0

100.0

200.0

300.0

400.0

500.0

600.0

700.0

800.0

0.0 200.0 400.0 600.0 800.0

(e) Chakdara + Zulam Br.

M u

n d a D a m S

i t e

June

y = 1.4208x - 174.23

R2 = 0.9808

0.0

200.0

400.0

600.0

800.0

1000.0

0.0 200.0 400.0 600.0 800.0

(f) Chakdara + Zulam Br.

M u

n d a D a m S

i t e

y = 1.5393x - 217.15

R² = 0.904

0.0

100.0

200.0

300.0

400.0

500.0

600.0

700.0

800.0

0.0 200.0 400.0 600.0

M u

n d a D a m S

i t e

(g) Chakdara + Zulam Br.

July

y = 0.446x + 192.1

R² = 0.9248

0.0

100.0

200.0

300.0

400.0

500.0

0.0 100.0 200.0 300.0 400.0 500.0

M u n d a D a m S

i t e

(h) Chakdara + Zulam Br.

August

September

y = 1.371x - 46.035

R2 = 0.8975

0.0

50.0

100.0

150.0

200.0

250.0

300.0

0.0 50.0 100.0 150.0 200.0 250.0

(i) Chakdara + Zulam Br.

October

y = 1.0356x + 9.6579

R2 = 0.9879

0.0

50.0

100.0

150.0

200.0

250.0

300.0

350.0

0.0 100.0 200.0 300.0 400.0

(j) Chakdara + Zulam Br.

M u n d

a D a m S

i t e

November

y = 0.7158x + 32.483

R2 = 0.9362

0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

0.0 50.0 100.0 150.0

(k) Chakdara + Zulam Br.

M u n d a

D a m S

i t e y = 0.7227x + 29.667

R² = 0.7827

0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

0.0 50.0 100.0 150.0

M u n d a D

a m S

i t e

(l) Chakdara + Zulam Br.

December




27

(iii) Regression coefficients shown in Table 6 forJanuary to November are satisfactory, beinggreater than 0.8 and for December is 0.76.Table-6 represents the summary of linear

regression between Munda Dam site andZalum Bridge + Chakdara with coefficient ofcorrelation and remarks for the acceptance of

equation.(iv) A series of composite river flows, covering

the period January 1956 – March 1999 wasderived by adding together the synthesizedseries at Zulam Bridge and naturalized seriesat Chakdara.

(v) Using the afore-said monthly regressionequations and monthly flow series of ZulamBridge plus Chakdara, the synthesizedmonthly naturalized flow series at Munda

dam site was derived for January 1956 –March 1999 period. This series was thensupplemented by superimposing the

naturalized flow series for the period April1999 – March 2005.

Q Munda = Q Munda Naturalized – Canal Diversions

Table 6: Regression Between Monthly Flows of Munda dam site and Zulam Bridge + Chakdara

MonthEquation Between

Zulam Br. & Chakdara – KalamReg. Coeff.

R 2

Remarks

Jan QM = .9013 Qz+c + 14.313 0.93 Satisfactory

Feb QM = 0.8492 Qz+c+ 26.81 0.89 Satisfactory

Mar QM = 0.7959 Qz+c + 53.74 0.98 Satisfactory

Apr QM = 1.3041 Qz+c – 38.79 0.96 Satisfactory

May QM = 1.2533 Qz+c – 72.19 0.87 Satisfactory

Jun QM = 1.4208 Qz+c – 174.23 0.98 Satisfactory

Jul QM = 1.5393 Qz+c - 217.15 0.90 Satisfactory

Aug QM = 0.446 Qz+c + 192.10 0.92 Satisfactory

Sep QM = 1.371 Qz+c - 46.04 0.89 Satisfactory

Oct QM = 1.0356 Qz+c + 9.66 0.99 Satisfactory

Nov QM = 0.7158 Qz+c + 32.48 0.94 Satisfactory

Dec QM = 0.7227 Qz+c + 29.67 0.76 Satisfactory

(vi) Feasibility Report of the project by NipponKoei (2000) estimates the diversions from theSwat river basin (u/s of the dam site), aresummarized in Table-7. Present annualdiversions are estimated at 70.1 m3/sec. Note

that Nippon Koei’s estimated futurediversions are our present diversions.

(vii) Estimated present monthly diversions fromPanjkora and Swat rivers upstream of Munda

dam stations were then subtracted from theflow series to get final inflows values for damsite. Table-8 shows the monthly reservoir

inflows and their comparison with previousestimates.

Table 7: Present Diversions

Month Present Diversions

(m3/sec)

January 31.87

February 38.35

March 47.49

April 91.61

May 108.76

June 117.42

July 72.05August 74.03

September 108.70

October 74.29

November 42.39

December 34.02

Source: Nippon Koi (2000).




28

Table 8: Comparison of Reservoir Monthly Inflow (m3/s) Estimates

Month Current Study

(m3/sec)

Nippon Koei Co1. (m

3/sec)

NESPAK 2

(m3/sec)

Jan 53.4 29.7 38.0 Feb 81.6 34.8 48.0 Mar 202.8 100.9 111.6

Apr 423.4 250.2 290.7 May 478.2 337.3 438.2 Jun 626.9 530.3 562.7 Jul 617.7 623.2 616.0 Aug 308.1 372.4 464.8 Sep 142.0 88.0 293.8 Oct 75.2 35.8 96.2 Nov 59.7 36.1 48.8 Dec 64.0 34.1 43.6

1 Results of “Feasibility Study on Development of Munda Multipurpose Dam Project”, conducted

by Nippon Koei Co. Ltd. & Nippon Giken Inc., Volume I-IV, 2000.

2 Results of “Pre-feasibility Study Report of Munda Dam Project” conducted by National

Engineering Services of Pakistan & Pakistan Engineering Services, Lahore, 1992.

5. CONCLUSIONS AND

RECOMENDATIONS

The mean annual flow estimated by NipponKoei is 206.2 m3/sec as compared with 261m3/sec for present conditions indicates that

inflows estimated by this study are on higher sideas during previous studies no single gauging

station was established in Punjkora river sub basin which represents the 42.9% of the total

catchment of proposed Munda dam. Although theoutcome of this study is quite promising but forit’s more generalization is required to obtain

comprehensive data of reasonable number ofsites. Without this it would be a site specific caseand could be used only for the site having the

similar hydro metrological conditions.

ACKNOWLEDGEMENT

Authors are thankful to the Director, Centreof Excellence in Water Resources Engineering,Lahore to provide the opportunity to conduct a

very useful study. In addition to this at last butnot least authors are extremely thankful to SWH

directorate WAPDA and project Consultants to provide required data for the study.

REFRENCES

1. Awan, N.M. “Hydrologic Analysis for Rising of

Baran Dam in NWFP” Centre of Excellence in

Water Resource Engineering, U.E.T. Lahore,

Technical Report No.8, Publication No.44, 1985.

2. Chow, V.T., “Handbook of Applied hydrology”.

McGraw-Hill, New York, pp.1418, 1964.

3. Falkland, A. “Hydrology and Water Resources of

Small Islands” a Practical Guide, Studies and

Reports in Hydrology, UNESCO, Australia, 1991.

4. Mutreja, K.N., “Applied Hydrology”, Tata

McGraw Hill Publishing Company, Ltd., New

Delhi, 1986.

5. NESPAK (Pvt.) Ltd. and PES (Pvt.) Ltd., “Pre-feasibility Report of Munda Multipurpose Dam

Project” National Engineering Services Pakistan

(Pvt.) Ltd. and Pakistan Engineering Services,

Lahore, 1992.

6. Nippon Koei Co. Ltd and Nippon Giken Inc.,

“Feasibility Study on Development of Munda

Multipurpose Dam Project” Nippon Koei Co. Ltd

and Nippon Giken Inc., Lahore, Volumes I-IV,

2000.

7. Shaw, M., Elizabeth. “Hydrology in Practice”,

Second Edition, Van Nestrand Reinhold

International Co. Ltd., 1988.

8. Singh, V. P. and Smokid Buapeng, “Effect ofRainfall-Excess Determination on Runoff

Computation”, Water Resources Bulletin 13,

Vol.3, 1977, pp. 499-514.

9. WMO, Guide to Hydrological Practices,

Secretariat of World Meteorological Organisation,

Geneva, WMO No.168, 1974.

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Modified Correlation Techniq Case Study Munda Dam S.M. Saeed Shah

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