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Nature of solute transport in the Godavari Basin, India
Journal of Hydrology, 103 (1988) 375-392 Elsevier Science Publishers B.V., Amsterdam
375 Printed in The Netherlands
[21 N A T U R E OF SOLUTE T R A N S P O R T IN THE GODAVARI BASIN, INDIA
G. BIKSHAM ~ and V. SUBRAMANIAN 2
School of Environmental Sciences, Jawaharlal Nehru University, New Delhi-110 067 (India) (Received June 16, 1987; revised and accepted January 3, 1988)
ABSTRACT Biksham, G. and Subramanian, V., 1988. Nature of solute transport in the Godavari Basin, India. J. Hydrol., 103: 375-392. The nature of solute transport of the Godavari basin has been studied based on 59 river and four rain water samples collected four times during 1977 1980. The Godavari basin annually transports 16.8 × 106t of solute load representing 6% of chemical load from the Indian subcontinent. The annual chemical erosion rate is 49t km ~yr ~ after correcting for atmospheric recycling. The tributaries flowing through the Deccan traps (basalt) covering 48% of the basin area are responsible for 85% of the dissolved transport. The remaining 15% is contributed by granites and other rock types. The sedimentary rocks located in the lower part of the basin covering 7% of the basin area actually retain 7 x 10°t of the annual dissolved load. Individual elemental fluxes and their rates have also been calculated. Temporal variations in the dissolved transport are quite pronounced. The mean TDS of the Godavari River, 250 mg 1 1 is much higher than the Indian and world average river water composition.
INTRODUCTION
River transport of materials is receiving increasing attention because of the need to quantify various sources and sinks in the hydrological cycle. Solute load of a river is a good indicator of the intensity of the chemical weathering in the drainage basin (Garrels and Mackenzie, 1971). Data on several large rivers indicate that in the present environment, solute transport is 20-25% of the solid transport (Gibbs, 1972; Subramanian, 1979; Stallard and Edmond, 1983; Hui et al., 1982; Meybeck, 1983; Sarin and Krishnaswami, 1984). Solute transport by many medium-size rivers in tropical areas are interesting for the weathering process (Carbonnel and Meybeck, 1975; Ray et al., 1984). Solute transport is also relevant for pollution studies (Nriagu, 1979 as quoted in Biksham, 1985). In the Indian subcontinent, studies on river basins are of recent origin Present address: College of Marine Studies, Robinson Hall, University of Delaware, Newark, DE 19716 (U.S.A.) For correspondence.
0022-1694/88/$03.50
(~ 1988 Elsevier Science Publishers B.V.
376 (Subramanian, 1979; B i k s h a m and Subramanian, 1980; A b b a s and Subramanian, 1984; S a r i n a n d K r i s h n a s w a m i , 1984; R a y e t al., 1984). Peninsular India, which has a number of medium-size rivers, a varying amount o f r a i n f a l l , a n d a t r o p i c a l e n v i r o n m e n t , offers a w i d e s c o p e f o r h y d r o l o g i c a l s t u d i e s . T h e G o d a v a r i b a s i n h a s b e e n c h o s e n h e r e s i n c e i t is t h e l a r g e s t a m o n g the non-Himalayan rivers of India. GODAVARI RIVER BASIN T a b l e 1 s u m m a r i z e s t h e h y d r o l o g i c d a t a a n d T a b l e 2 t h e l i t h o l o g i c d a t a for t h e G o d a v a r i R i v e r b a s i n . T h e G o d a v a r i d i s c h a r g e s 92 k m 3 o f w a t e r a n n u a l l y i n t o t h e B a y o f B e n g a l , w h i c h is o n e - f o u r t h o f t h a t o f t h e G a n g e s a n d 1.7% o f t h a t o f t h e A m a z o n . T h e b a s i n is c o v e r e d w i t h A r c h e a n ( P e n i n s u l a r g n e i s s ) , Cuddapah and Gondwanas overlain by tertiary basaltic Deccan traps ( K r i s h n a n , 1969 a s q u o t e d in B i k s h a m , 1985). A l l u v i a l d e p o s i t s a r e c o m m o n in t h e r i v e r b a s i n p a r t i c u l a r l y t o w a r d s r i v e r m o u t h . I n a d d i t i o n to l i t h o l o g y several dams, coal mining, irrigation and industries are other major factors to be k e p t in m i n d w h i l e s t u d y i n g t h e s o l u t e l o a d o f t h e r i v e r b a s i n . T h e m e a n r a i n fall o v e r t h e b a s i n is 1 1 8 5 m m y r i ( I n d i a n M e t e o r o l o g y D e p a r t m e n t r e p o r t s ) a n d m e a n e l e v a t i o n 420m.
Methodology Fifty-nine samples were collected at various locations of the main river and t r i b u t a r i e s d u r i n g D e c e m b e r 1977, J u n e 1978, M a y 1979, A u g u s t 1979, a n d J u l y 1980. I n a d d i t i o n , f o u r r a i n w a t e r s a m p l e s f r o m t h r e e l o c a t i o n s w e r e a l s o TABI,E 1 Mean discharge at sampling locations No.
1 2 3 4 5 6 7 8 9 10
River/tributary
Godavari Godavari Godavari Godavari Pranahita Penganga Wainganga Indravati Manjeera Sabari
Location
Nanded Kaleshwaram Perur Rajamundry Tekra P.G. Bridge Pauni P. Gudam Raipalli Konta
Area
54 103 260 310 100 19 36 42 16 20
Q
8 17 80 92 43 5 16 23 2 14
Sample* Code
No.
GN GK GP GR TP PG WG ID MJ SB
1 6 1l 23 34 41 44 46 48 54
5 10 22 33 37 43 45 50 58
Area 10:~km:~:Q = 10~M;~(km:~). * Code is shown in Fig. 1 and mentioned in tables and text. The sample nos. are given in Table 2 and 4, etc. Locations of some samples (e.g. 51 to 53, etc.) not given. These are from small streams and not significant in terms of solute transport.
377 TABLE 2 G o d a v a r i Basin: D i s t r i b u t i o n of rock t y p e s River
Granites and hard rocks
Pranahita
39.0 (38.8) 1.1 (23.5) 33.5 (80.4) 17.5 (87.4) 23.8 (20.1)
8.4 (13.6) 2.5 (13.6) 22.9 (19.2)
66.3 (55.7)
122.2 (39.0)
36.4 (11.6)
149.4 (47.7)
Manjeera Indravati Sabri Godavari* Total
Sed. rocks
Deccan traps
2.6 (2.6)
59.0 (58.6) 24.1 (76.5)
Recent alluv,
Basin area
Mean e l e v a t i o n (m) 443
6.1 (5.1)
100.6 (32.1) 31.5 (10.0) 41.8 (13.4) 20.0 (6.4) 119.1 (38.0)
6.1 (1.9)
313.0 (100.0)
420
562 490 580
T h e figures are in t h o u s a n d k m 2, except for t h e elevation, T h e figures in b r a c k e t s are % of e a c h rock types. * M a i n G o d a v a r i n o t covered by t r i b u t a r i e s .
r~
?lB
76
L~.i.k/~X)
BlO
1512
all
r .... ~ ~ ~ i ./ ~ ~.~ )
\
~%-'X
22
~, Roi..0,,~
/
2o
%_._
-
la
'-
-16°W
71~E
~ Ix "~"
71~
Fig. 1. S a m p l i n g locations.
?
8~
C~
82
I
25U
Klw
B~ I
16
378 collected. The sample locations are shown in Fig. 1. pH and alkalinity were measured in the field. In the laboratory the samples first were filtered through 0.45 micron membrane filters to remove the suspended solids. Then once again pH and alkalinity were determined on the filtered samples. Standard analytical procedures were used for bicarbonates (HCO3) and chlorides (C1) and a Cecil double-beam spectrophotometer was used for the determination of phosphates (Po4) and silicates. Sulphates (So4) were determined by barium perchlorate titration after passing the water samples through a Dowex cation-exchange column. Cations were determined with an atomic absorption spectrophotometer (AAS-1); calcium (Ca) and magnesium (Mg) by the absorption mode and sodium (Na) and potassium (K) by the emission mode. The electrical conductivity was measured with a Systronics direct reading conductivity meter. The details of procedures are outlined elsewhere (Biksham, 1985). RESULTS AND DISCUSSION The chemical analysis for the 59 water and four rain water samples are given in Table 3. The tables also show detailed anion and cation charge balance in milliequivalents, electrical conductivity (EC), total dissolved salts (TDS), and ratio of EC/TDS. The charge balance and ratio of EC/TDS are within the accepted limits, except for few samples (Table 3, nos. 38 and 47), confirming the reliability of the analytical results. The major anions constitute more than 70% of the total dissolved salts concentrations. Bicarbonates constitute more than 65% of the anions ranging from 44 to 336mgl 1. The other anions such as C1 range between 7 and 50 mg 1 1, So4 between 0 and 35 mg l-1 and Po4 is very low between 0 and 0.26 mg 1 1. The major cations constitute nearly 25% of the TDS. Among the cations Na and Ca are prominent with Na ranging from 2 to 100mgl 1, Ca ranging from 5 to 56mgl 1, while Mg concentration is around 10mgl i and K is around 5 m g l '. Dissolved silica (SiO2) ranges from 1 to 31 mgl 1 averaging 10 mg 1 1. Table 4 summarises the range of values for water chemistry of the Godavari basin. Approximate TDS values can be computed from the measured conductivity (gS cm 1) values using a conversion factor of 0.7 for fresh waters (Devis and Dewiest, 1962). The analyzed TDS values (sum of all ions including silica) plotted against the measured conductivity (Fig. 2) shows a slope of 0.71 thus confirming the reliability of our analysis. The TDS of individual samples range h'om 42 mg 1 ~(Sabari, Table 3, no. 59) to 548 mg 1 1 (Godavari at Nanded, Table 3, no. 1). At the river mouth the TDS variation is between 95 and 256mgl-1 (no. 27 and 23, Table 3). The dry (non-monsoon) season samples generally show higher TDS than those for the wet (monsoon) season. The seasonal variation factor (dry/wet) on the main Godavari at Nanded, Kaleshwaram and Rahjamundry (up stream to down stream) are 2.1, 2.3 and 2.7 respectively with the values increasing towards the river mouth. Similarly the seasonal variation factors for tributaries, the Manjeera, Pranahita, Wardha and Sabari are 4.2, 3.9, 2.8 and 2.2, respectively. The high seasonal variation factor for the Manjeera and Pranahita may be due to relatively saline ground water input during dry seasons.
1 GH 2 GH 3GH 4 GH 5 GK 6 GK 7GK 8 GK 9GK 1 0G K 11 GKR 12GKR 13 G K R 14 G K R 15GKR 16GKR 17 G K R 18 GKR 19GKR 20 G K R 21 GKR 22GKR 23GR 2 4G R 25GR 26 GR 2 7G R 28GAR
B C D E B A B C D E A B C A A A B C D B A A A B C D E B
Godavari River
S a m p l e No.
7.7 7.2 7.4 7.6 8.4 8.2 8.1 8.4 8.1 7.6 8.3 8.1 8.1 8.2 8.0 7.5 8.4 7.8 8.1 8.4 7.5 7.7 8.0 8.1 6.7 7.4 7.3 8.2
pH
800.0 700.0 350.0 510.0 670.0 380.0 570.0 725.0 275.0 450.0 340.0 500.0 720.0 365.0 185.0 245.0 190.0 460.0 245.0 190.0 245.0 175.0 220.0 215.0 220.0 180.0 175.0 190.0
Cond.
336.0 247.3 158.2 122.1 292.0 210.0 184.5 238.2 122.2 99.9 219.5 240.0 253.3 219.5 108.0 137.5 96.5 195.2 125.2 102.5 172.0 117.0 152.0 114.2 102.5 85.0 44.4 102.4
HCO~
46.2 40.6 12.4 35.5 39.0 25.0 49.5 28.4 10.7 28.4 14.0 42.6 46.2 22.5 16.5 17.0 14.2 26.4 7.0 14.2 17.0 12.0 15.4 14.2 14.2 12.5 10.7 14.2
CI
0.19 0.19 0.15 0.18 0.62 0.05 0.12 0.26 0.15 0.12 0.06 0.15 0.00 0.06 0.02 0.04 0.07 0.08 0.10 0.10 0.02 0.02 0.01 0.19 0.10 0.10 0.10 0.10
PO 4
14.6 35.0 8.0 20.0 14.0 7.5 19.5 35.0 5.8 25.0 8.3 13.2 25.0 9.3 8.0 8.0 14.2 2.7 3.5 11.0 8.0 8.3 9.6 10.2 5.8 7.5 5.8 11.2
SO 4
15.1 13.5 4.5 9.0 6.3 27.5 20.0 10.5 3.7 8.0 30.0 31.0 11.0 29.0 20.5 24.0 27.0 10.3 3.0 25.0 11.0 20.0 20.0 20.5 5.0 5.5 5.5 10.5
SiO,,
C h e m i c a l a n a l y s i s of G o d a v a r i River, t r i b u t a r i e s a n d r a i n w a t e r
TABLE 3
44.0 32.8 33.0 35.0 40.0 36.0 27.2 10.8 22.5 19.5 20.0 28.0 10,8 22.0 26.0 24.0 22.0 12.8 38.4 26.8 24.5 24.0 26.0 30.0 7.7 21.8 8.5 26.0
Ca
32.0 20.0 6.0 12.5 24.0 2.4 7.9 16.5 6.0 10.7 12.0 19.2 25,0 10.8 6.0 10.0 2.6 15.8 3.2 12.0 9.5 5.0 9.0 2.4 5.7 4.5 5.0 3.4
Mg
44.5 75.0 22.2 25.5 38.5 43.0 39.5 102.0 21.0 42.0 23.0 21.5 125.0 26.0 11.5 17.5 7.8 52.0 5.5 20.0 17.5 7.5 16.0 8.1 10.6 13.7 12.2 7.9
Na
15.0 6.5 3.5 5.5 10.0 13.8 8.5 6.5 2.6 5.5 9.5 6.7 7,5 10.8 6.8 8.2 2.2 5.7 1.9 1.5 8.2 5.0 8.0 2.2 4.1 2.6 2.8 2.2
K
547.6 470.9 248.0 265.3 464.4 365.3 356.7 448.2 194.7 239.1 336.4 102.4 503,8 350.0 203.3 246.2 186.6 321.0 187.8 213.1 267.7 198.8 256.0 202.0 155.7 153.2 95.0 177.9
TDS
0.68 0.67 0.71 0.52 0.69 0.96 0.63 0.62 0.71 0.53 0.99 0.68 0.70 0.96 1.10 1.01 0.98 0.70 0.77 1.12 1.09 1.14 1.16 0.94 0.71 0.85 0.54 0.94
TDS/ Cond.
7.12 5.93 3.11 3.42 6.20 4.30 4.83 5.44 2.43 2.96 4.17 5.41 5.97 4.43 2.40 2.90 2.28 4.00 2.33 2.31 3.47 2.43 3.13 2.49 2.20 1.90 1.15 2.32
Total anion
7.15 6.71 3.20 4.02 5.90 4.22 3.94 6.50 2.60 3.82 3.23 4.08 8.22 3.39 2.47 2.99 1.71 4.35 2.47 3.23 2.98 2.06 2.94 2.10 1.42 2.12 1,44 1.98
Total cation
0.03 0.78 0.08 0.60 0.30 0.09 - 0.89 1.06 0.17 0.86 - 0.94 1.33 2.25 1.03 0.06 0.09 - 0.57 0.34 0.14 0.92 0.49 0.37 -(/.19 0.39 0.79 0.22 0.28 0.34
Diff.
8.2 8.2 8.2 7.3 7.4
29 GAR 30 GAR 31 GAR 32 GAR 33 GAR
Tributaries and rain 8.4 34 PR A 8.0 35 PR B 8.1 36 PR C 7.3 37 PR E 7.4 38 WR C 7.0 39 WR D 7.7 40 WR E 7.8 41PG C 7.5 42 PG D 8.2 43 PG E 7.4 44WG C 7.8 45 WG C 7.8 46 ID A 7.0 47 MN D 7.9 48 M J C 7.5 49 M J D 7.7 50 M J B 6.9 51SL C 52 SL D 7.0 53 SL E 6.9 7.5 54 SB A 55SB B 8.2 56 SB C 6.5 8.2 57SB D
B B B C C
pH
Sample No.
TABLE 3 (continued)
water 395.0 550.0 595.0 185.0 630.0 202.0 460.0 560.0 345.0 330.0 195.0 325.0 115.0 650.0 610.0 280.0 830.0 112.0 93.0 79.0 73.0 57.0 68.0 74.0
220.0 230.0 250.0 238.0 280.0
Cond.
205.0 240.0 253.3 44.4 307.5 112.5 155.5 283.9 118.5 94.4 85.0 156.2 79.0 225.2 244.2 85.2 366.0 60.3 32.5 27.8 45.0 29.2 42.2 25.4
117.0 117.0 120.0 108.6 90.5
HCO~
23.0 42.6 42.6 7.1 44.4 7.1 17.8 24.9 7.1 21.3 8.9 16.0 11.0 42.6 48.0 14.2 42.5 10.7 8.9 7.1 9.0 10.3 5.3 8.9
17.5 14.2 14.2 17.8 37.2
CI
0.05 0.15 0.19 0.15 0.10 0.08 0.10 0.10 0.08 0.10 0.10 0.30 0.02 0.14 0.00 0.15 0.05 0.10 0.06 0.08 0.00 0.06 0.12 0.08
0.10 0.10 0.10 0,14 0.08
PO~
7.9 13.2 28.0 2.7 4.0 2.7 20.0 4.0 2.7 1.0 0.0 1.0 7.5 2.7 20.0 5.8 24.0 25.0 2.7 0.5 6.0 9.2 4.0 16.0
9.2 14.0 9.5 0.6 1.0
SO 4
28.0 31.0 13.5 5.5 15.0 3.7 17.0 14.3 5.2 1.0 3.7 4.8 3.5 6.6 4.9 3.7 12.0 5.8 4.5 1.0 11.0 10.2 4.7 3.3
7.5 16.0 5.0 6.2 5.4
SiO=,
34.0 28.0 9.6 13.0 9.4 23.8 23.0 7.7 39.2 25.0 20.5 38.4 30.0 21.0 10.5 17.6 56.0 17.6 10.8 5.0 12.0 22.0 7.8 8.8
26.0 26.0 30.0 20.3 21.0
Ca
3.6 19.2 16.5 5.0 16.5 7.0 14.5 21.3 9.0 10.7 6.0 7.0 1.2 12.4 18,3 6.0 26.5 1.6 3.8 4.7 2.0 1.2 5.0 5.0
3.4 3.4 6.0 7.0 10.0
Mg
22.0 31.5 56.0 28.5 52.0 4,5 23.0 56.0 7.2 15.0 6.9 9.0 5.0 10.0 100.0 2.6 41.0 3.2 3.6 3.2 3.0 2.0 2.6 2.3
8.5 7.5 8.5 13.8 25.0
Na
2.4 2.4 2.5 3.5 5.1
9.2 6.7 5.7 2.5 6.2 1.8 4.5 5.7 1.9 2.6 2.6 2.6 5.5 5.2 5.6 3.2 16.0 1.8 2.6 2.6 4.0 1.5 2.6 2.2
K
332.8 412.4 425.4 108.9 455.1 163.2 275.4 417.9 190.9 171.1 133.7 235.3 152.7 325.8 451.5 138.5 584.1 126.1 69.5 52.0 92.0 85.7 74.3 72.0
191.6 200.6 195.8 177.9 195.3
TDS
0.84 0.75 0.71 0.59 0.72 0.81 0.60 0.75 0.55 0.52 0.69 0.72 1.33 0.50 0.74 0.49 0.70 1.13 0.75 0.66 1.26 1.50 1.09 0.97
0.87 0.87 0.78 0.75 0.70
TDS/ Con&
7.70 1.81 0.84 0.67 1.12 0.96 0.93 1.00
1.92
3.04 1.76 4.95 5.77
1.65
4.17 5.41 5.94 0.99 6.38 2.10 3.47 5.44 2.20 2.17
2.61 2.61 2.57 2.30 2.56
Total anion
0.84 1.00 1.32 0.98 1.01
1.07
1.20
3.19 4.52 4.42 2.36 4.25 2.01 3.46 4.72 3.06 2.85 1.88 2.95 1.95 2.64 6.52 1.57 7.17
2.01 1.96 2.42 2.28 3.09
Total cation
0.99 0.90 1.52 1.37 - 2.13 0.10 0.01 0.72 0.86 0.67 0.24 0.09 0.19 2.32 0.75 - 0.36 0.53 0.62 0.23 0.17 -0.12 0.36 0.05 0.00
0.60 0.65 0.14 0.02 0.53
Diff.
-
E D D D D D
6.7 7.5 6.1 6.2 5.8 5.6
68.0 335.0 23.0 8.0 8.0 13.0
16.7 180.2 4.5 2.6 3.0 4.0
7.1 23.8 7.1 7.1 7.1 7.1
0~08 0.05 0.00 0.00 0.00 0.00
1.0 0.8 0.6 0.8 0.8 0.5
4.8 3.7 0.2 0.1 0.1 0.0
3.0 27.5 4.6 3.5 2.0 3.0
4.2 4.5 2.1 1.5 0.5 1.0
C h e m i c a l e l e m e n t s i n m g l 2; a n i o n a n d c a t i o n i n m e q I 1; c o n d . = c o n d u c t i v i t y . Legend: A = D e c e m b e r 1977 B - J u n e 1978 C M a y 1979 D A u g u s t 1979 E J u l y 1980 GN - Nanded GK Kaleshwaram GKR Between GK and GR GR = Rajahmundry GAR After Rajahmundry PR = Pranahita WR - Wardha PG - Penganga WG = Wainganga ID - Indravati MN = Maner MJ - Manjira SU Sileru SB Sabari KN Kinnerasani RW - Rain water
58SB 59KN 60RW 61RW 62RW 63RW
2.6 22.2 0.6 1.5 0.1 0.5
2.2 5.1 0.6 1.8 0.6 0.5
41.7 267.9 20.3 19.0 14.2 16.7
0.61 0.80 0.88 2.37 1.77 1.29
0.59 3.64 0.29 0.26 0.27 0.28
0.66 2.84 0.44 0.41 0.16 0.27
0.17 0.80 0.16 0.15 0.11 0.01
382 TABLE 4 R a n g e of chemical composition of river water
Ion
Godavari
pH Cond. (itS cm l) HCO:~ C1 PO SO4 SiO~ Ca Mg Na K
TDS
Tributaries
Max.
Min.
Max.
Min.
Mean
8.4 800
7.2 175
8.2 830
6.5 57
7.2 339
336 46 0.62 35 31 44 32 125 15 547
444 7 0.01 0.6 3 7.7 24 5.5 1.5 95
336 48 0.19 28 31 56 26 100 16 455
167 7 0.0 0.0 1 3 12 2 1.5 42
156 21 0.11 10 12 23 10 25 5 232
All u n i t s in m g l 1, except pH and conductivity.
Mean chemical composition The mean chemical composition at eleven locations (four on the main Godavari and seven on the tributaries) are given in Table 5. The table also includes data on mean rain water composition (R W), mean of 59 water samples (GM) and river water composition after correcting for the atmospheric contribution. Table 6 compares average composition of the Godavari with that of the Indian average and world average. 600
500
./..
<~ 400 u3
o>, o
J
30c
20C
1001
100
200
300
400
500
600
CONDUCTIVITY
Fig. 2. Total dissolved salts - conductivity plot
700
800
383 TABLE
5
M e a n s of g r o u p s of s a m p l e s Sample group
pH
Cond.
HCO 3
CI
PO 4
SO 4
SiO 2
Ca
Mg
Na
K
TDS
GN (0t 04) GK (05 10) (iP (15 21) (iR (23 33) GM (01 59) RW (60~3) PR (34 37) WR (3~ 40) PG (41 43) WG (44 45) I|) (46 46) MJ (47 50) SB (54 58) Godavari*
7.48 8.13 7.96 7.73 7.72 5.93 7.95 7.37 7.83 7.60 7.80 7.53 7.42
590.00 511.67 251.43 219.82 339.22 13.00 431.25 430.67 411.67 260.00 115.00 592.50 68.00 206.82
215.90 191.13 133.84 104.87 146.87 3.53 185.68 191.83 165.60 120.60 79.00 230.15 31.70 101.35
33.68 30.17 16.04 16.55 21.35 7.10 28.83 23.10 17.77 12.45 11.00 36.83 8.12 9.45
0.18 0.22 0.06 0.10 0.11 0.00 0.14 0.09 0.09 0.20 0.02 0.09 0.07 0.10
19.40 17.80 7.91 7,67 10.18 0.68 12.95 8..90 2.57 0.50 7.50 13.13 7.24 7.00
10.53 12.67 17.26 9.74 11.85 0.08 19.50 11.90 6.83 4.25 13.50 6.80 6.80 9.66
36.20 26,00 24.93 22.12 22.79 3.28 21.15 18.73 23.97 29.45 30.00 26.28 10.72 18.84
17.63 11.25 8.44 5.44 9.52 i.28 11.08 12.67 13.67 6.50 1.20 15.80 3.48 4.16
41.80 47.67 18.83 11.98 24.32 0.73 34.50 26.50 26.07 7.95 5.00 38.40 2.50 11.26
7.63 7.82 4.93 3.44 5.11 0.88 6.03 4.17 3.40 2.60 5.50 7.50 2.50 2.56
382.93 344.72 232.25 181.91 252.09 17.53 319.84 297.89 259.96 184.50 152.72 374.96 73.13 164.38
Legend: GN Godavari-Nanded; GK Godavari-Kaleshwaram; GP Godavari-Perur; GR Godavari-Rajahmundry; GM M e a n of 59 samples; RW - R a i n water; PR P r a n a h i t a : WR W a r d h a ; PG P e n g a n g a ; WG W a i n g a n g a ; ID Indravathi; MJ M a n j e e r a ; SB Sabari. * After d e d u c t i n g the r a i n w a t e r c o m p o s i t i o n from the G o d a v a r i ri ve r c o m p o s i t i o n . All u n i t s in m g l I, except pH and conductivity.
T h e m e a n r a i n w a t e r c o m p o s i t i o n ( T D S 1 7 . 5 m g l 1) is a b o u t 1 0 % o f t h a t o f t h e m e a n G o d a v a r i w a t e r c o m p o s i t i o n a t t h e m o u t h (182 m g 1 1). T h e G o d a v a r i is p r i m a r i l y a m o n s o o n f e d r i v e r w i t h m o r e t h a n 9 5 % o f a n n u a l w a t e r d i s c h a r g e d u r i n g t h e m o n s o o n p e r i o d ( B i k s h a m , 1985). T h e r e f o r e t h e r a i n w a t e r c o m position is subtracted from the river water for rough estimation of the impact of the chemical weathering process. Based on mean chemical composition, the TABLE 6 Composition of Godavari, Indian and world river waters
pH Cond. (zS cm 1) HCO:, C1 PO 4 SO~ SiO=, Ca Mg Na K
TDS
a
b
c
7.9 319
7.7 220
7.7 339
139.4 21.9 0.12 12.9 13.7 22.7 7.7 28.5 5.7 253
104.9 16.6 0.1 7.7 9.7 22.1 5.4 12.0 3.4 182
146.9 21.4 0.1 10.2 12.0 22.8 9.5 24.3 5.1 252
d
e
74 15 12 7 30 7 12 3 161
52 9.6 0.01 8.7 10.4 13.5 3.6 7.4 1.4 106
a = discharge weighted mean; b = actual comp. at Rajahmundry (GR); c = mean of 59 samples (GM); d = mean of Indian rivers (Subramanian, 1983); e = world average (Meybeck, 1982). All units in mgl 1, except pH and conductivity.
384 TABLE 7 Dissolved ions: Relative order of abundance (in mg 1 1) Location*
Ions
GN GR PR WR PG MJ SL MN KN WG SB ID GR RW
HCQ HCO3 HCO3 HCO:~ HCO:~ HCO3 HCO:~ HCO:~ HCO:~ HCQ HCO:~ HCO:~ HCO:~ HCQ
Na Na Na Na Na Na Ca C1 Ca Ca Ca Ca Ca C1
Ca Cl C] CI C1 CI C1 Ca C1 C1 CI SiO2 C1 Mg
C1 Ca Ca Ca Ca Ca SO4 Mg Na Na SO4 CI Na Ca
SO4 SO4 SiO~ Mg Mg Mg SiO2 Na SiO~ Mg SiO~ SO4 SiO~ Mg
Mg SiO~ SO4 SiO~ SiO2 SO4 Na SiO2 K SiO2 Mg K SO4 Na
SiO2 Mg Mg SO4 SO4 K Mg K Mg K Na Na Mg SO,
K K K K K SiO2 K SO~ SO4 SO4 K Mg K SiO~
* Locations are given in Fig. 1. individual ions are a r r a n g e d in order of relative c o n c e n t r a t i o n in Table 7. Such a r r a n g e m e n t b r o a d l y indicate t h a t the G o d a v a r i River w a t e r can be grouped into two types: (a) N a H C Q C 1 d o m i n a n t water; Na is the h i g h e s t c o n s t i t u e n t of the TDS next to bicarbonate. The t r i b u t a r i e s and the m a i n G o d a v a r i d r a i n i n g t h r o u g h the D e c c a n traps (basalt) c a r r y this type of water. The high c o n c e n t r a t i o n of Na and C1 indicates their a t m o s p h e r i c origin. This type of w a t e r g e n e r a l l y has high TDS. (b) Ca HCO3C1 d o m i n a n t water; this type of w a t e r has high Ca next to b i c a r b o n a t e s and is a s s o c i a t e d with the s e d i m e n t a r y rock types.
Dissolved transport Dissolved t r a n s p o r t (solute) at v a r i o u s stations of the basin, c a l c u l a t e d from the a v e r a g e TDS (Table 4) and ten y e a r s of m e a n d i s c h a r g e (Biksham, 1985), is presented in the Table 8. The table c o n t a i n s i n f o r m a t i o n on: (a) q u a n t i t y of each c o n s t i t u e n t ; (b) rate in t km 2yr 1; (c) p e r c e n t a g e of each c o n s t i t u e n t in the solute flux; and (d) total rate of chemical erosion. F i g u r e 3 shows the down s t r e a m v a r i a t i o n in elemental c o m p o s i t i o n of the m a j o r c a t i o n and a n i o n s in the G o d a v a r i basin. The G o d a v a r i River with an a n n u a l w a t e r d i s c h a r g e of 92 km ~ t r a n s p o r t s 16.8 × 106t of solutes into the B a y of Bengal. This is a b o u t 6% of a n n u a l dissolved load from the I n d i a n s u b c o n t i n e n t ( S u b r a m a n i a n , 1979) and 0.5% (i.e 24th r a n k ) of the global dissolved flux (Meybeck, 1976). On the main G o d a v a r i River, the dissolved t r a n s p o r t shows d o w n s t r e a m i n c r e a s e from 3.1 × 106 t (Nanded) to 18.5 × 106 t (Perur). At the river m o u t h , in spite of more
385
additions by the Sabari tributary (about I × 106 t) the dissolved load decreased to 16.8 × 106t. The dissolved load of individual tributaries ranges from 0.9 × 106 t for the Manjeera to 13.6 × 106t for the Pranahita (Table 8).
TABLE
8
Dissolved flux (103 t yr River and t r i b u t a m e s Station
HCO 3
1) (a), r a t e of c h e m i c a l erosion (t km
2 yr
1) (b), and p e r c e n t a g e of each c o n s t i t u e n t (%) for the G o d a v a n
CI
PO 4
SO 4
SiO 2
Ca
Mg
Na
K
Total
1770.38 33.929 56.38 ;t249.27 31.577 55.45 106~0.68 41.048 57.63 9679.75 31.448 57.65 13556.05 44.042 58.26 325.36 1.057 21/.11 9354.40 30.391 61.65
276.14 5.152 8,79 512.83 4,984 8,75 1280.22 4.920 6,91 1527.98 4.964 9.10 1970.53 6.402 8.47 655.33 2.129 40,51 872.65 2.835 5,75
1.46 0.027 0.05 3.74 0.036 0.06 4.90 0.019 0.03 9.40 0.031 0.06 995 0.032 0.04 0.00 0.000 0.00 9,40 0.031 0.06
159.08 2.968 5.07 302.60 2.941 5.16 631.56 2.427 3.41 708.19 2.301 4.22 939.74 3,053 4.04 62.30 0.202 3.85 645.69 2.098 4.26
86.30 1.610 2.75 215.3;t 2,093 3.67 1377.12 5.293 7.4;] 898.67 2.920 5.35 1094.15 3.555 4.70 7.15 0.023 0.44 891.51 2.896 5.88
296.84 5.538 9.45 442.00 4.295 7.54 1989.30 7.645 10.73 2041.51 6.633 12.16 2103.50 6.834 9.04 302.28 0.982 18.68 1739.23 5.651 11.46
144.53 2.696 4.60 191.25 1.859 3.26 673.74 2.589 3.64 501.78 1.630 2.99 878.57 2,854 3.78 117.68 0.382 7.27 384.09 1.248 2.53
342.76 6.395 10.92 810.33 7.875 13.83 1502.52 5.774 6.11 1105.92 3.593 6.59 2244.45 7.292 9.65 66.92 0.217 4.14 1039.00 3.376 6.85
62.53 1.167 1.99 132.88 1.291 2.27 393.30 1.512 2.12 317.18 1.030 1.89 471.36 1.531 2.03 80.76 0.262 4.99 236.41 0.768 1.56
3140.01 56.582 100.00 5860.24 56.951 I(X).00 18533.32 71,227 100.(X} 1679038 54.550 I(X).00 23268.30 75.596 100.00 1617.79 5256 1(X).00 15172.59 49.294 I(X).(X}
7891.19 72.529 58.05 2666.48 66.662 t;4.40 745.20 40.500 63.70 19115.48 53.675 65.37 1793,30 42.698 51.73 552,36 34.523 61.38 131/.17 21.508 43.35
1225.06 11.260 9.01 321.09 8.(}27 7.75 79.95 4.345 6.83 196.71 5.541 6.75 249.70 5.945 7.20 88.38 5.524 9.82 110.19 5.509 11.10
5.74 0.053 0.04 1.30 0.032 0.03 0,42 0.023 0.04 3.16 0.089 0.11 0.45 11.011 0.01 0.20 0.013 I).02 0.92 0.046 0.09
550.38 5.059 4.05 123.71 3.093 2.99 11.5 0.628 0.99 7.90 0.223 0.27 170.25 4.054 4.91 31.50 1.969 3.50 98.25 4.912 9.2)
828.75 7.617 6.10 165.4l 4.135 3.99 30.75 1.671 2.6;t 67.15 1.892 2.39 ;{06.45 7.296 8.84 16.32 1,020 1.81 92.28 4.614 9.30
898.87 8.262 6.61 260.;t9 6.510 6.29 107.85 5861 9.22 465.31 13107 15.,(Xi 681.00 16.214 19.64 63,06 3941 7.01 145.47 7274 14.66
470.69 4.326 3.46 176.07 4.402 4.25 61.50 3.342 5.26 102.70 2.893 3.52 27.24 0.649 0.79 37.92 2.37(I 4.21 47,22 2.361 4.76
1466.25 13.477 10.79 368.35 9.209 8.90 117.30 6.375 10.03 t25.61 3.538 4.31 113.50 2.702 3.27 92.16 5,760 10.24 33.9;t 1.696 3.42
256.06 2.354 1.66 57.92 1,448 1.40 15.;30 0.832 1,31 41.1/8 1,157 1.41 124.85 2.973 3.60 18.iX) 1,125 2.00 33.93 1.696 3.42
13592.99 I24.936 1(X1.00 4140.72 103.516 100.00 1169.82 63.577 ]/10,00 2915.10 82.115 11X)90 3466.74 82.542 l(g)./)0 899.90 56244 1(X1.00 922.;15 49.617 I(X).911
G o d m ari R i t er
GN
GK
(]P
(]R
GM
RW
Diffofence*
a b % a b % a b % a b % a b % a b '% a b %
Tributaries
PR
WR
PG
WG
ll)
MJ
SB
a b %, a I) % a b % a b '% a
h ", a 6 % a b %
Legend: GN Godavari-Nanded; GK Godavari-Kaleshwaram; GM M e a n of 59 samples; RW rain water; PR P r a n a h i t a ; WR dravathi; M J M a n j e e r a : SB Sabari.
GP Godavari-Perur; GR Godavari-Rajahm u ndry: W a r d h a : PG P e n g a n g a ; WG W a i n g a n g a ; lI) In
* After deducting the rain w a t e r composition from the Godavari River composition.
386
Elemental fluxes Inorganic carbon accounts for about 25% of total transport at most of the sampling locations except for the Sabari (17%). The rate of carbon transport is around 6t km-2yr 1. But for some tributaries flowing through deccan traps (basalt) the value is up to 14 t km 2yr 1. Since the dissolved organic carbon (DOC) in rivers is important (DOC = 10ppm, Meybeck, 1982), the values for inorganic C given here represent the lower limit of the total carbon transport in the Godavari. The C1 transport of the Godavari is around 1.5 x 10~t yr with a rate of 5 t km ~yr- ~. The maxium rate for C1 (11 t km 2yr ~was observed for the Pranahita subbasin, which can be understood in terms of high C1 content in rain water in this part of the basin (Table 8). The Godavari (a) (a)
106 tonnes krn2/yr
,,'~,~.-p 10 6 t o n n e s --~ t / k r n 2 / y r
CHLORIDE
"~
103 tonnes . Kg/krnL/yr
PHOSPHORUS
~
"-'~:~/
.,:6~ (' 00~
~
SULPHUR
103 t o n
m2/yr
SILICO N
~
,f'a~.--P 106 t o n nes ~ t/km2/Y r
387 ,"S'~'~ lO3 tonnes
b)
~ ~L" ilk rn2/yr (u.,,,
,orn, ,or o,,
POTASSIUM
'
~
rC.
CALCIUM
M2"~AGN ESIUM Fig. 3. Elemental variation. (a) Among major anionic constituents; (b) among major cationic constituents. transports around 253,000 t of sulphur yr 1 at a rate of 0.8 t km 2yr 1, ranging from 1.7t km ~yr -1 (Pranahita) to 0.07t km 2yr 1 (Wainganga). Similarly, the Godavari transports 270,000 t of Si at a rate of 0.9 t km 2yr 1. The four major cations (Ca, Mg, K, Na) account for about 56% of the total elemental fluxes. The transport of Ca is highest among these four at 6.5 t km ~yr 1. For the other elements, Mg, Na and K, the rates are 1.6, 3.6 and 1.0, respectively. Calcium mobility is higher from the rivers draining the granitic terrain, whereas Na is higher in the Deccan traps region. The rate of erosion for K is more or less uniform except for the Indravati and P r a n a h i t a (around 3t km 2yr 1). The tributaries flowing through Deccan traps (Pranahita and Wardh) contribute Mg three times the average for the entire basin. Figure 3 shows the downstream variations in individual solute transport. The rates for C1, K, S and Si are more or less uniform. Ca and C show increase at mid basin (GP) and drop at the river mouth. A steep decrease of Na and a slight decrease of Mg below Kaleshwaram is also evident from the figures. Geology as a controlling factor Table 9 summarises the lithological control on the river water chemistry. The tributaries and main river flowing through the Deccan traps (with 48% of basin area) contribute more than 85% of the dissolved load while the remaining 15% is contributed by Sabari and Indravati, flowing through granites and other
388 TABLE 9 Contribution to elemental dissolved load by geological units Element
a
b
a + b
c
(~ C] P S Si Ca Mg Na K
2230 1737 3.12 282 313 1341 662 2276 389
442 360 0.18 88 120 827 74 147 159
2672 2097 3.30 370 440 2168 736 2423 548
1936 1527 3.10 233 270 2042 501 1105 317
d
e 736 570 0.20 137 170 126 235 1318 231"
28 27 6 37 39 5 32 54 42*
a Deccan traps; b = granites and other hard rocks: c = Out flow at river mouth; d = Quantity retained by sedimentary rocks: e = Percentage of dissolved load retained/contributed (*) by sedimentary rocks. Figures in 10:~tyr ~. hard rocks. The s e d i m e n t a r y rocks (7% of basin area) located in the lower part of the basin do not c o n t r i b u t e a n y significant q u a n t i t y of the solute load to the basin. At R a h j a m u n d r y (GR) the river delivers 16 x 106t of solute load. The depletion of individual ions in the s e d i m e n t a r y rock area r a n g e s from 5% of inflow (Ca) to 54% (Na). Above the s e d i m e n t a r y rock area the river carries 23 x l0 Gt of solute load, and loses 7 x 10Gt d u r i n g passage t h r o u g h the 200 km r e a c h of s e d i m e n t a r y terrain. The depletion of 7 x 10~t of dissolved elements in these s e d i m e n t a r y rocks m a y possibly be due to the selective ionic e x c h a n g e from the river w a t e r to the sediments. These s e d i m e n t a r y r o c k s c o n t r i b u t e 56 x 10Gt of suspended sediments to the river t r a n s p o r t total of 170 x 10~t yr 1 (Biksham, 1985). M i n e r a l o g i c a l studies at the river m o u t h indicated t h a t more t h a n 60% of clay f r a c t i o n of these sediments were m o n t m o r i l l o n i t e (Biksham, 1985). The large a m o u n t (1.3 x 10~t, or 54% of input) of sodium r e t a i n e d in this r e a c h indicates t h a t the clays after some selective ionic e x c h a n g e m a y have become Na montmorillonites.
Variation in solute transport The q u a n t i t y of a n n u a l dissolved t r a n s p o r t (Td) of the river varies m a i n l y depending on the q u a n t i t y of discharge. An a t t e m p t is made here to elucidate the r e l a t i o n s h i p between discharge and the solute t r a n s p o r t based on the available d a t a (Table 10). The a n n u a l Td varies by a f a c t o r of 3.6 from 8.2 to 29.2 x 106t in the 10-year period, whereas the d i s c h a r g e (Q) v a r i a t i o n f a c t o r over the c o r r e s p o n d i n g period is only 1.6. M o n t h l y v a r i a t i o n s are quite signific a n t (Table 11) and they suggest the following points: (a) more t h a n 87% of the a n n u a l Q and Td are t r a n s p o r t e d d u r i n g t h r e e m o n t h s (July, A u g u s t and September) and d u r i n g the same period 99.6% of the a n n u a l sediment load is t r a n s p o r t e d : (b) except for three months, the chemical load (Td) is more t h a n
389 TABLE 10 A n n u a l v a r i a t i o n of dissolved t r a n s p o r t Year
1969 70 1970 71 1977 78 1978 79 [979 8(} Mean
Q
TDS
Td
(km3yr ~)
(mgl 1)
(1060
Mean (106t)
95 104 87 121 66 94.5 92.3*
237 ~ 280 b 230 c 178 ~ 125 ~ 210 161
22.5 29.2 20.0 21.5 8.2 20.3 16.8
21.8 25.8 21.2 16.4 11.5 19.4 16.8
Td *
' Mean of eleven, and bsix m o n t h s data (unpubl. reports, CSMRS, 1973). ' Mean of two (seasons) samples, p r e s e n t study. '~Mean of ten years data, CWC. * Based on respective years TDS and mean Q of ten years.
the sediment load (Ts), and the ratio of Ts/Td varies from 14.7 (August) to 0.05 (January) with an annual average of 11.8; (c) the TDS increases with discharge; (d) the discharge weighted mean annual TDS (227 mgl -]) is very close to the mean for the monsoon seasons (226mgl 1); (e) the annual Td estimation, l
74
I
76
I
I
78
i
80
82
814
I
22!
C"
i i
L_j.,.,.
f
,o_ Nx
4~
~,!
INDRAVATI
-18
"-~, ..,. ~
'ok ~
g
250 K m
_16°W
,ire
',+
?
Fig. 4. Solute erosion rate v a r i a t i o n in the Godavari Basin.
82 I
B4 I
+
390 TABLE 11 Monthly variation of mass transport (1969 70) Month
Q (10~m :~)
Td ( TDS ) (103 t)
Ts ( T S M ) (mg 1 ~)
Ts/ T d
June July Aug. Sept. Oct. Nov. Dec. Jan. Feb. March April May Annual
730 17,300 30,030 35,900 4,550 2,700 1,500 870 570 520 390 370 95,460
160 2,800 4,260 11,790 950 700 340 200 135 130 120 100 21,690
75 32,510 50,880 173,500 750 142 20 10 10 56 50 60 257,900
0.5 11.5 11.9 14.7 0.8 0.2 0.06 0.05 0.07 0.4 0.4 0.6 11.8
(219) (162) (142) (328) (209) (259) (227) (230) (236) (250) (308) (270) (227)*
(103) (1879) (1695) (4832) (165) (53) (13) (12) (8) (11) (13) (16) (2702)*
Q ~ water discharge (103m3); T d = dissolved load; Ts - suspended load. * Discharge weighted mean.
16.8 × 106t might be slightly reduced if annual TDS values (not available) were weighted against respective annual discharge; and (f) the highest TDS and TSM correspond to the highest discharge month (September). Figure 4 shows the variations in solute fluxes throughout the Godavari basin.
Atmospheric input The dissolved transport of continental rivers includes a significant quantity of atmospheric contribution through rain water and aerosol particles. Such atmospheric contributions should be subtracted in arriving at the actual rate of chemical erosion over the river basins (Meybeck, 1983; Holland et al., 1986). An attempt is made herein to estimate the atmospheric input over the Godavari basin based on four rain water samples. The composition of these samples (TDS 17.6 mg 1 1) is in broad agreement with rain water from the other parts of India (Handa, 1968, 1972). The annual contribution of dissolved salts by rain water over the basin are estimated based on rainfall of 1185mm yr 1 (Indian Meteorology Department reports). The amount of rain water input over the basin is around 370 km ~, which is nearly four times the annual runoff of the Godavari River (92 km2). Table 12 summarises the various components of mass balance of solute transport in the basin. Overall the atmospheric input over the Godavari basin is 37% of solute transport of the river. For the individual ions, HCO3, SO4, Na, Ca, Mg, and K it amounts to 13, 29, 25, 59, 94 and 100% of river output, respectively. This broadly indicates the cyclic nature of the many ions in river transport, which is very significant for estimating chemical erosion.
391 TABLE 12 Chemical mass balance over the Godavari Basin Ion
HCO:~ CI SO 4 SiO,, Ca Mg Na K Total
Water composition (mg 1 1)
Mass transport (t km 2yr i)
Godavari, rain
India mean, rain
Godavari, mean
Rain
River
Sun
3.5 7.1 0.7 0.1 3.3 1.3 0.7 0.9 17.5
7.0 6.0 1.7 0.8 2.9 8.5 1.3 0.6 28.9
104.8 16.6 7.7 9.7 22.1 5.5 12.0 4.9 181.9
4.8 8.4 0.8 0.1 3.9 1.5 0.9 1.0 20.8
31.5 5.0 2.8 4.8 6.6 1.6 3.6 1.0 56.9
36.3 13.4 3.6 4.9 10.9 3.1 4.5 2.0 77.7
Rain contr. (%)
13 63 22 2 36 48 20 50 27
Figures are rounded to the nearest digit/number. REFERENCES Abbas, N. and Subramanian, V., 1984. Erosion and sediment transport in the Ganges River basin, India. J. Hydrol., 69: 17~182. Biksham, G., 1985. Geochemistry of the Godavari River basin. Ph.D. Thesis, Jawaharlal Nehru University, 265 pp. (unpubl.). Biksham, G. and Subramanian, V., 1980. Chemical and sediment mass transfer in the Godavari River basin in India. J. Hydrol., 46: 331--342. Carbonnel, J.P. and Meybeck, M., 1975. Quantity variations of the Mekong river at Phnompenh, Cambodia and chemical transport in the Mekong basin. J. Hydrol., 27:249 265. Conway, E.J., 1942. Mean geochemical data in oceanic evolution. Proc. R. Irish Acad., 48:119 159. Davis, S.N. and Dewiest, R.J.M., 1962. Hydrogeology. Wiley, New York, N.Y., 463 pp. Ericson, E., 1960. The yearly circulation of chloride and sulphur in nature, meteorological, geochemical and pedological implications, part II. Tellus, 12:63 109. Garrels, R.M. and Mackenzie, F.T., 1971. Evolution of sedimentary rocks. Norton, New York, N.Y., 339 pp. Gibbs, R.J., 1967. The geochemistry of the Amazon River system, Part I, The factors that control the salinity and composition and concentration of suspended solids. Geol. Soc~ Am., Bull., 78: 1203 1232. Gibbs, R.J., 1972. Water chemistry of the Amazon River. Geochim. Cosmochim. Acta, 36:1061 1066. Handa, B.K., 1968. Chemical composition of rain water over Calcutta. Indian J. Meteorol, Geophys., 20: 150-154. Handa, B.K., 1972. Geochemistry of the Ganges River. Ind. J. Geohydrol., 13:71 78. Holland, H.D., Lazer, B. and McCaffrey, M., 1986. Evolution of the atmosphere and oceans. Nature, 320:27 33. Hui, H.M., Stallard, R.F. and Edmond, J.M., 1982. Major ion chemistry of some large Chinese rivers. Nature, 298: 550-553. Livingstone, D.A., 1963. Chemical composition of rivers and lakes, data of geochemistry. U.S. Geol. Surv., Prof. Pap., 440-G, 64 pp. Meybeck, M., 1976. Total dissolved transport by world major rivers. Hydrol. Sci. Bull., 21:265 289. Meybeck, M.. 1982. Carbon, nitrogen and phosphorus transport by world rivers. Am. J. Sci., 282: 401 450.
392 Meybeck, M., 1983. Atmospheric inputs and river transport of dissolved substances. Dissolved load of rivers and surface water quantity/quality relationship. Proc. Hamburg Symp., IAHS, Publ. No. 141. Ray, S.B., Mohanti, M. and Somayajulu, B.L.K., 1984. Suspended matter, major cations and dissolved silica in the estuarine waters of Mahanadi River, India. J. Hydrol., 69:183 196. Reinson, G.E., 1976. Hydrogeochemistry of Genog River basin, N.S. Wales and Victoria. Australian J. Mar. Fresh Water Res., 27:165 -185. Sarin, M.M. and Krishnaswamy, S., 1984. Major ion chemistry of Ganga Brahputra river systems, India. Nature, 312: 538-541. Stallard, R.F. and Edmond, J.M., 1981. Geochemistry of the Amazon 1. Precipitation chemistry and the marine contribution to the dissolved load at the time of peak discharge. 3. Geophys. Res., 86: 9844-9858. Stallard, R.T. and Edmond, J.M., 1983. Geochemistry of the Amazon - 2. The influence of geology and weathering environment on the dissolved load. J. Geophys. Res., 88:9671 9688. Subramanian, V., 1979. Chemical and suspended sediment characteristics of rivers of India. J. Hydrol., 44:37 55.
375 Printed in The Netherlands
[21 N A T U R E OF SOLUTE T R A N S P O R T IN THE GODAVARI BASIN, INDIA
G. BIKSHAM ~ and V. SUBRAMANIAN 2
School of Environmental Sciences, Jawaharlal Nehru University, New Delhi-110 067 (India) (Received June 16, 1987; revised and accepted January 3, 1988)
ABSTRACT Biksham, G. and Subramanian, V., 1988. Nature of solute transport in the Godavari Basin, India. J. Hydrol., 103: 375-392. The nature of solute transport of the Godavari basin has been studied based on 59 river and four rain water samples collected four times during 1977 1980. The Godavari basin annually transports 16.8 × 106t of solute load representing 6% of chemical load from the Indian subcontinent. The annual chemical erosion rate is 49t km ~yr ~ after correcting for atmospheric recycling. The tributaries flowing through the Deccan traps (basalt) covering 48% of the basin area are responsible for 85% of the dissolved transport. The remaining 15% is contributed by granites and other rock types. The sedimentary rocks located in the lower part of the basin covering 7% of the basin area actually retain 7 x 10°t of the annual dissolved load. Individual elemental fluxes and their rates have also been calculated. Temporal variations in the dissolved transport are quite pronounced. The mean TDS of the Godavari River, 250 mg 1 1 is much higher than the Indian and world average river water composition.
INTRODUCTION
River transport of materials is receiving increasing attention because of the need to quantify various sources and sinks in the hydrological cycle. Solute load of a river is a good indicator of the intensity of the chemical weathering in the drainage basin (Garrels and Mackenzie, 1971). Data on several large rivers indicate that in the present environment, solute transport is 20-25% of the solid transport (Gibbs, 1972; Subramanian, 1979; Stallard and Edmond, 1983; Hui et al., 1982; Meybeck, 1983; Sarin and Krishnaswami, 1984). Solute transport by many medium-size rivers in tropical areas are interesting for the weathering process (Carbonnel and Meybeck, 1975; Ray et al., 1984). Solute transport is also relevant for pollution studies (Nriagu, 1979 as quoted in Biksham, 1985). In the Indian subcontinent, studies on river basins are of recent origin Present address: College of Marine Studies, Robinson Hall, University of Delaware, Newark, DE 19716 (U.S.A.) For correspondence.
0022-1694/88/$03.50
(~ 1988 Elsevier Science Publishers B.V.
376 (Subramanian, 1979; B i k s h a m and Subramanian, 1980; A b b a s and Subramanian, 1984; S a r i n a n d K r i s h n a s w a m i , 1984; R a y e t al., 1984). Peninsular India, which has a number of medium-size rivers, a varying amount o f r a i n f a l l , a n d a t r o p i c a l e n v i r o n m e n t , offers a w i d e s c o p e f o r h y d r o l o g i c a l s t u d i e s . T h e G o d a v a r i b a s i n h a s b e e n c h o s e n h e r e s i n c e i t is t h e l a r g e s t a m o n g the non-Himalayan rivers of India. GODAVARI RIVER BASIN T a b l e 1 s u m m a r i z e s t h e h y d r o l o g i c d a t a a n d T a b l e 2 t h e l i t h o l o g i c d a t a for t h e G o d a v a r i R i v e r b a s i n . T h e G o d a v a r i d i s c h a r g e s 92 k m 3 o f w a t e r a n n u a l l y i n t o t h e B a y o f B e n g a l , w h i c h is o n e - f o u r t h o f t h a t o f t h e G a n g e s a n d 1.7% o f t h a t o f t h e A m a z o n . T h e b a s i n is c o v e r e d w i t h A r c h e a n ( P e n i n s u l a r g n e i s s ) , Cuddapah and Gondwanas overlain by tertiary basaltic Deccan traps ( K r i s h n a n , 1969 a s q u o t e d in B i k s h a m , 1985). A l l u v i a l d e p o s i t s a r e c o m m o n in t h e r i v e r b a s i n p a r t i c u l a r l y t o w a r d s r i v e r m o u t h . I n a d d i t i o n to l i t h o l o g y several dams, coal mining, irrigation and industries are other major factors to be k e p t in m i n d w h i l e s t u d y i n g t h e s o l u t e l o a d o f t h e r i v e r b a s i n . T h e m e a n r a i n fall o v e r t h e b a s i n is 1 1 8 5 m m y r i ( I n d i a n M e t e o r o l o g y D e p a r t m e n t r e p o r t s ) a n d m e a n e l e v a t i o n 420m.
Methodology Fifty-nine samples were collected at various locations of the main river and t r i b u t a r i e s d u r i n g D e c e m b e r 1977, J u n e 1978, M a y 1979, A u g u s t 1979, a n d J u l y 1980. I n a d d i t i o n , f o u r r a i n w a t e r s a m p l e s f r o m t h r e e l o c a t i o n s w e r e a l s o TABI,E 1 Mean discharge at sampling locations No.
1 2 3 4 5 6 7 8 9 10
River/tributary
Godavari Godavari Godavari Godavari Pranahita Penganga Wainganga Indravati Manjeera Sabari
Location
Nanded Kaleshwaram Perur Rajamundry Tekra P.G. Bridge Pauni P. Gudam Raipalli Konta
Area
54 103 260 310 100 19 36 42 16 20
Q
8 17 80 92 43 5 16 23 2 14
Sample* Code
No.
GN GK GP GR TP PG WG ID MJ SB
1 6 1l 23 34 41 44 46 48 54
5 10 22 33 37 43 45 50 58
Area 10:~km:~:Q = 10~M;~(km:~). * Code is shown in Fig. 1 and mentioned in tables and text. The sample nos. are given in Table 2 and 4, etc. Locations of some samples (e.g. 51 to 53, etc.) not given. These are from small streams and not significant in terms of solute transport.
377 TABLE 2 G o d a v a r i Basin: D i s t r i b u t i o n of rock t y p e s River
Granites and hard rocks
Pranahita
39.0 (38.8) 1.1 (23.5) 33.5 (80.4) 17.5 (87.4) 23.8 (20.1)
8.4 (13.6) 2.5 (13.6) 22.9 (19.2)
66.3 (55.7)
122.2 (39.0)
36.4 (11.6)
149.4 (47.7)
Manjeera Indravati Sabri Godavari* Total
Sed. rocks
Deccan traps
2.6 (2.6)
59.0 (58.6) 24.1 (76.5)
Recent alluv,
Basin area
Mean e l e v a t i o n (m) 443
6.1 (5.1)
100.6 (32.1) 31.5 (10.0) 41.8 (13.4) 20.0 (6.4) 119.1 (38.0)
6.1 (1.9)
313.0 (100.0)
420
562 490 580
T h e figures are in t h o u s a n d k m 2, except for t h e elevation, T h e figures in b r a c k e t s are % of e a c h rock types. * M a i n G o d a v a r i n o t covered by t r i b u t a r i e s .
r~
?lB
76
L~.i.k/~X)
BlO
1512
all
r .... ~ ~ ~ i ./ ~ ~.~ )
\
~%-'X
22
~, Roi..0,,~
/
2o
%_._
-
la
'-
-16°W
71~E
~ Ix "~"
71~
Fig. 1. S a m p l i n g locations.
?
8~
C~
82
I
25U
Klw
B~ I
16
378 collected. The sample locations are shown in Fig. 1. pH and alkalinity were measured in the field. In the laboratory the samples first were filtered through 0.45 micron membrane filters to remove the suspended solids. Then once again pH and alkalinity were determined on the filtered samples. Standard analytical procedures were used for bicarbonates (HCO3) and chlorides (C1) and a Cecil double-beam spectrophotometer was used for the determination of phosphates (Po4) and silicates. Sulphates (So4) were determined by barium perchlorate titration after passing the water samples through a Dowex cation-exchange column. Cations were determined with an atomic absorption spectrophotometer (AAS-1); calcium (Ca) and magnesium (Mg) by the absorption mode and sodium (Na) and potassium (K) by the emission mode. The electrical conductivity was measured with a Systronics direct reading conductivity meter. The details of procedures are outlined elsewhere (Biksham, 1985). RESULTS AND DISCUSSION The chemical analysis for the 59 water and four rain water samples are given in Table 3. The tables also show detailed anion and cation charge balance in milliequivalents, electrical conductivity (EC), total dissolved salts (TDS), and ratio of EC/TDS. The charge balance and ratio of EC/TDS are within the accepted limits, except for few samples (Table 3, nos. 38 and 47), confirming the reliability of the analytical results. The major anions constitute more than 70% of the total dissolved salts concentrations. Bicarbonates constitute more than 65% of the anions ranging from 44 to 336mgl 1. The other anions such as C1 range between 7 and 50 mg 1 1, So4 between 0 and 35 mg l-1 and Po4 is very low between 0 and 0.26 mg 1 1. The major cations constitute nearly 25% of the TDS. Among the cations Na and Ca are prominent with Na ranging from 2 to 100mgl 1, Ca ranging from 5 to 56mgl 1, while Mg concentration is around 10mgl i and K is around 5 m g l '. Dissolved silica (SiO2) ranges from 1 to 31 mgl 1 averaging 10 mg 1 1. Table 4 summarises the range of values for water chemistry of the Godavari basin. Approximate TDS values can be computed from the measured conductivity (gS cm 1) values using a conversion factor of 0.7 for fresh waters (Devis and Dewiest, 1962). The analyzed TDS values (sum of all ions including silica) plotted against the measured conductivity (Fig. 2) shows a slope of 0.71 thus confirming the reliability of our analysis. The TDS of individual samples range h'om 42 mg 1 ~(Sabari, Table 3, no. 59) to 548 mg 1 1 (Godavari at Nanded, Table 3, no. 1). At the river mouth the TDS variation is between 95 and 256mgl-1 (no. 27 and 23, Table 3). The dry (non-monsoon) season samples generally show higher TDS than those for the wet (monsoon) season. The seasonal variation factor (dry/wet) on the main Godavari at Nanded, Kaleshwaram and Rahjamundry (up stream to down stream) are 2.1, 2.3 and 2.7 respectively with the values increasing towards the river mouth. Similarly the seasonal variation factors for tributaries, the Manjeera, Pranahita, Wardha and Sabari are 4.2, 3.9, 2.8 and 2.2, respectively. The high seasonal variation factor for the Manjeera and Pranahita may be due to relatively saline ground water input during dry seasons.
1 GH 2 GH 3GH 4 GH 5 GK 6 GK 7GK 8 GK 9GK 1 0G K 11 GKR 12GKR 13 G K R 14 G K R 15GKR 16GKR 17 G K R 18 GKR 19GKR 20 G K R 21 GKR 22GKR 23GR 2 4G R 25GR 26 GR 2 7G R 28GAR
B C D E B A B C D E A B C A A A B C D B A A A B C D E B
Godavari River
S a m p l e No.
7.7 7.2 7.4 7.6 8.4 8.2 8.1 8.4 8.1 7.6 8.3 8.1 8.1 8.2 8.0 7.5 8.4 7.8 8.1 8.4 7.5 7.7 8.0 8.1 6.7 7.4 7.3 8.2
pH
800.0 700.0 350.0 510.0 670.0 380.0 570.0 725.0 275.0 450.0 340.0 500.0 720.0 365.0 185.0 245.0 190.0 460.0 245.0 190.0 245.0 175.0 220.0 215.0 220.0 180.0 175.0 190.0
Cond.
336.0 247.3 158.2 122.1 292.0 210.0 184.5 238.2 122.2 99.9 219.5 240.0 253.3 219.5 108.0 137.5 96.5 195.2 125.2 102.5 172.0 117.0 152.0 114.2 102.5 85.0 44.4 102.4
HCO~
46.2 40.6 12.4 35.5 39.0 25.0 49.5 28.4 10.7 28.4 14.0 42.6 46.2 22.5 16.5 17.0 14.2 26.4 7.0 14.2 17.0 12.0 15.4 14.2 14.2 12.5 10.7 14.2
CI
0.19 0.19 0.15 0.18 0.62 0.05 0.12 0.26 0.15 0.12 0.06 0.15 0.00 0.06 0.02 0.04 0.07 0.08 0.10 0.10 0.02 0.02 0.01 0.19 0.10 0.10 0.10 0.10
PO 4
14.6 35.0 8.0 20.0 14.0 7.5 19.5 35.0 5.8 25.0 8.3 13.2 25.0 9.3 8.0 8.0 14.2 2.7 3.5 11.0 8.0 8.3 9.6 10.2 5.8 7.5 5.8 11.2
SO 4
15.1 13.5 4.5 9.0 6.3 27.5 20.0 10.5 3.7 8.0 30.0 31.0 11.0 29.0 20.5 24.0 27.0 10.3 3.0 25.0 11.0 20.0 20.0 20.5 5.0 5.5 5.5 10.5
SiO,,
C h e m i c a l a n a l y s i s of G o d a v a r i River, t r i b u t a r i e s a n d r a i n w a t e r
TABLE 3
44.0 32.8 33.0 35.0 40.0 36.0 27.2 10.8 22.5 19.5 20.0 28.0 10,8 22.0 26.0 24.0 22.0 12.8 38.4 26.8 24.5 24.0 26.0 30.0 7.7 21.8 8.5 26.0
Ca
32.0 20.0 6.0 12.5 24.0 2.4 7.9 16.5 6.0 10.7 12.0 19.2 25,0 10.8 6.0 10.0 2.6 15.8 3.2 12.0 9.5 5.0 9.0 2.4 5.7 4.5 5.0 3.4
Mg
44.5 75.0 22.2 25.5 38.5 43.0 39.5 102.0 21.0 42.0 23.0 21.5 125.0 26.0 11.5 17.5 7.8 52.0 5.5 20.0 17.5 7.5 16.0 8.1 10.6 13.7 12.2 7.9
Na
15.0 6.5 3.5 5.5 10.0 13.8 8.5 6.5 2.6 5.5 9.5 6.7 7,5 10.8 6.8 8.2 2.2 5.7 1.9 1.5 8.2 5.0 8.0 2.2 4.1 2.6 2.8 2.2
K
547.6 470.9 248.0 265.3 464.4 365.3 356.7 448.2 194.7 239.1 336.4 102.4 503,8 350.0 203.3 246.2 186.6 321.0 187.8 213.1 267.7 198.8 256.0 202.0 155.7 153.2 95.0 177.9
TDS
0.68 0.67 0.71 0.52 0.69 0.96 0.63 0.62 0.71 0.53 0.99 0.68 0.70 0.96 1.10 1.01 0.98 0.70 0.77 1.12 1.09 1.14 1.16 0.94 0.71 0.85 0.54 0.94
TDS/ Cond.
7.12 5.93 3.11 3.42 6.20 4.30 4.83 5.44 2.43 2.96 4.17 5.41 5.97 4.43 2.40 2.90 2.28 4.00 2.33 2.31 3.47 2.43 3.13 2.49 2.20 1.90 1.15 2.32
Total anion
7.15 6.71 3.20 4.02 5.90 4.22 3.94 6.50 2.60 3.82 3.23 4.08 8.22 3.39 2.47 2.99 1.71 4.35 2.47 3.23 2.98 2.06 2.94 2.10 1.42 2.12 1,44 1.98
Total cation
0.03 0.78 0.08 0.60 0.30 0.09 - 0.89 1.06 0.17 0.86 - 0.94 1.33 2.25 1.03 0.06 0.09 - 0.57 0.34 0.14 0.92 0.49 0.37 -(/.19 0.39 0.79 0.22 0.28 0.34
Diff.
8.2 8.2 8.2 7.3 7.4
29 GAR 30 GAR 31 GAR 32 GAR 33 GAR
Tributaries and rain 8.4 34 PR A 8.0 35 PR B 8.1 36 PR C 7.3 37 PR E 7.4 38 WR C 7.0 39 WR D 7.7 40 WR E 7.8 41PG C 7.5 42 PG D 8.2 43 PG E 7.4 44WG C 7.8 45 WG C 7.8 46 ID A 7.0 47 MN D 7.9 48 M J C 7.5 49 M J D 7.7 50 M J B 6.9 51SL C 52 SL D 7.0 53 SL E 6.9 7.5 54 SB A 55SB B 8.2 56 SB C 6.5 8.2 57SB D
B B B C C
pH
Sample No.
TABLE 3 (continued)
water 395.0 550.0 595.0 185.0 630.0 202.0 460.0 560.0 345.0 330.0 195.0 325.0 115.0 650.0 610.0 280.0 830.0 112.0 93.0 79.0 73.0 57.0 68.0 74.0
220.0 230.0 250.0 238.0 280.0
Cond.
205.0 240.0 253.3 44.4 307.5 112.5 155.5 283.9 118.5 94.4 85.0 156.2 79.0 225.2 244.2 85.2 366.0 60.3 32.5 27.8 45.0 29.2 42.2 25.4
117.0 117.0 120.0 108.6 90.5
HCO~
23.0 42.6 42.6 7.1 44.4 7.1 17.8 24.9 7.1 21.3 8.9 16.0 11.0 42.6 48.0 14.2 42.5 10.7 8.9 7.1 9.0 10.3 5.3 8.9
17.5 14.2 14.2 17.8 37.2
CI
0.05 0.15 0.19 0.15 0.10 0.08 0.10 0.10 0.08 0.10 0.10 0.30 0.02 0.14 0.00 0.15 0.05 0.10 0.06 0.08 0.00 0.06 0.12 0.08
0.10 0.10 0.10 0,14 0.08
PO~
7.9 13.2 28.0 2.7 4.0 2.7 20.0 4.0 2.7 1.0 0.0 1.0 7.5 2.7 20.0 5.8 24.0 25.0 2.7 0.5 6.0 9.2 4.0 16.0
9.2 14.0 9.5 0.6 1.0
SO 4
28.0 31.0 13.5 5.5 15.0 3.7 17.0 14.3 5.2 1.0 3.7 4.8 3.5 6.6 4.9 3.7 12.0 5.8 4.5 1.0 11.0 10.2 4.7 3.3
7.5 16.0 5.0 6.2 5.4
SiO=,
34.0 28.0 9.6 13.0 9.4 23.8 23.0 7.7 39.2 25.0 20.5 38.4 30.0 21.0 10.5 17.6 56.0 17.6 10.8 5.0 12.0 22.0 7.8 8.8
26.0 26.0 30.0 20.3 21.0
Ca
3.6 19.2 16.5 5.0 16.5 7.0 14.5 21.3 9.0 10.7 6.0 7.0 1.2 12.4 18,3 6.0 26.5 1.6 3.8 4.7 2.0 1.2 5.0 5.0
3.4 3.4 6.0 7.0 10.0
Mg
22.0 31.5 56.0 28.5 52.0 4,5 23.0 56.0 7.2 15.0 6.9 9.0 5.0 10.0 100.0 2.6 41.0 3.2 3.6 3.2 3.0 2.0 2.6 2.3
8.5 7.5 8.5 13.8 25.0
Na
2.4 2.4 2.5 3.5 5.1
9.2 6.7 5.7 2.5 6.2 1.8 4.5 5.7 1.9 2.6 2.6 2.6 5.5 5.2 5.6 3.2 16.0 1.8 2.6 2.6 4.0 1.5 2.6 2.2
K
332.8 412.4 425.4 108.9 455.1 163.2 275.4 417.9 190.9 171.1 133.7 235.3 152.7 325.8 451.5 138.5 584.1 126.1 69.5 52.0 92.0 85.7 74.3 72.0
191.6 200.6 195.8 177.9 195.3
TDS
0.84 0.75 0.71 0.59 0.72 0.81 0.60 0.75 0.55 0.52 0.69 0.72 1.33 0.50 0.74 0.49 0.70 1.13 0.75 0.66 1.26 1.50 1.09 0.97
0.87 0.87 0.78 0.75 0.70
TDS/ Con&
7.70 1.81 0.84 0.67 1.12 0.96 0.93 1.00
1.92
3.04 1.76 4.95 5.77
1.65
4.17 5.41 5.94 0.99 6.38 2.10 3.47 5.44 2.20 2.17
2.61 2.61 2.57 2.30 2.56
Total anion
0.84 1.00 1.32 0.98 1.01
1.07
1.20
3.19 4.52 4.42 2.36 4.25 2.01 3.46 4.72 3.06 2.85 1.88 2.95 1.95 2.64 6.52 1.57 7.17
2.01 1.96 2.42 2.28 3.09
Total cation
0.99 0.90 1.52 1.37 - 2.13 0.10 0.01 0.72 0.86 0.67 0.24 0.09 0.19 2.32 0.75 - 0.36 0.53 0.62 0.23 0.17 -0.12 0.36 0.05 0.00
0.60 0.65 0.14 0.02 0.53
Diff.
-
E D D D D D
6.7 7.5 6.1 6.2 5.8 5.6
68.0 335.0 23.0 8.0 8.0 13.0
16.7 180.2 4.5 2.6 3.0 4.0
7.1 23.8 7.1 7.1 7.1 7.1
0~08 0.05 0.00 0.00 0.00 0.00
1.0 0.8 0.6 0.8 0.8 0.5
4.8 3.7 0.2 0.1 0.1 0.0
3.0 27.5 4.6 3.5 2.0 3.0
4.2 4.5 2.1 1.5 0.5 1.0
C h e m i c a l e l e m e n t s i n m g l 2; a n i o n a n d c a t i o n i n m e q I 1; c o n d . = c o n d u c t i v i t y . Legend: A = D e c e m b e r 1977 B - J u n e 1978 C M a y 1979 D A u g u s t 1979 E J u l y 1980 GN - Nanded GK Kaleshwaram GKR Between GK and GR GR = Rajahmundry GAR After Rajahmundry PR = Pranahita WR - Wardha PG - Penganga WG = Wainganga ID - Indravati MN = Maner MJ - Manjira SU Sileru SB Sabari KN Kinnerasani RW - Rain water
58SB 59KN 60RW 61RW 62RW 63RW
2.6 22.2 0.6 1.5 0.1 0.5
2.2 5.1 0.6 1.8 0.6 0.5
41.7 267.9 20.3 19.0 14.2 16.7
0.61 0.80 0.88 2.37 1.77 1.29
0.59 3.64 0.29 0.26 0.27 0.28
0.66 2.84 0.44 0.41 0.16 0.27
0.17 0.80 0.16 0.15 0.11 0.01
382 TABLE 4 R a n g e of chemical composition of river water
Ion
Godavari
pH Cond. (itS cm l) HCO:~ C1 PO SO4 SiO~ Ca Mg Na K
TDS
Tributaries
Max.
Min.
Max.
Min.
Mean
8.4 800
7.2 175
8.2 830
6.5 57
7.2 339
336 46 0.62 35 31 44 32 125 15 547
444 7 0.01 0.6 3 7.7 24 5.5 1.5 95
336 48 0.19 28 31 56 26 100 16 455
167 7 0.0 0.0 1 3 12 2 1.5 42
156 21 0.11 10 12 23 10 25 5 232
All u n i t s in m g l 1, except pH and conductivity.
Mean chemical composition The mean chemical composition at eleven locations (four on the main Godavari and seven on the tributaries) are given in Table 5. The table also includes data on mean rain water composition (R W), mean of 59 water samples (GM) and river water composition after correcting for the atmospheric contribution. Table 6 compares average composition of the Godavari with that of the Indian average and world average. 600
500
./..
<~ 400 u3
o>, o
J
30c
20C
1001
100
200
300
400
500
600
CONDUCTIVITY
Fig. 2. Total dissolved salts - conductivity plot
700
800
383 TABLE
5
M e a n s of g r o u p s of s a m p l e s Sample group
pH
Cond.
HCO 3
CI
PO 4
SO 4
SiO 2
Ca
Mg
Na
K
TDS
GN (0t 04) GK (05 10) (iP (15 21) (iR (23 33) GM (01 59) RW (60~3) PR (34 37) WR (3~ 40) PG (41 43) WG (44 45) I|) (46 46) MJ (47 50) SB (54 58) Godavari*
7.48 8.13 7.96 7.73 7.72 5.93 7.95 7.37 7.83 7.60 7.80 7.53 7.42
590.00 511.67 251.43 219.82 339.22 13.00 431.25 430.67 411.67 260.00 115.00 592.50 68.00 206.82
215.90 191.13 133.84 104.87 146.87 3.53 185.68 191.83 165.60 120.60 79.00 230.15 31.70 101.35
33.68 30.17 16.04 16.55 21.35 7.10 28.83 23.10 17.77 12.45 11.00 36.83 8.12 9.45
0.18 0.22 0.06 0.10 0.11 0.00 0.14 0.09 0.09 0.20 0.02 0.09 0.07 0.10
19.40 17.80 7.91 7,67 10.18 0.68 12.95 8..90 2.57 0.50 7.50 13.13 7.24 7.00
10.53 12.67 17.26 9.74 11.85 0.08 19.50 11.90 6.83 4.25 13.50 6.80 6.80 9.66
36.20 26,00 24.93 22.12 22.79 3.28 21.15 18.73 23.97 29.45 30.00 26.28 10.72 18.84
17.63 11.25 8.44 5.44 9.52 i.28 11.08 12.67 13.67 6.50 1.20 15.80 3.48 4.16
41.80 47.67 18.83 11.98 24.32 0.73 34.50 26.50 26.07 7.95 5.00 38.40 2.50 11.26
7.63 7.82 4.93 3.44 5.11 0.88 6.03 4.17 3.40 2.60 5.50 7.50 2.50 2.56
382.93 344.72 232.25 181.91 252.09 17.53 319.84 297.89 259.96 184.50 152.72 374.96 73.13 164.38
Legend: GN Godavari-Nanded; GK Godavari-Kaleshwaram; GP Godavari-Perur; GR Godavari-Rajahmundry; GM M e a n of 59 samples; RW - R a i n water; PR P r a n a h i t a : WR W a r d h a ; PG P e n g a n g a ; WG W a i n g a n g a ; ID Indravathi; MJ M a n j e e r a ; SB Sabari. * After d e d u c t i n g the r a i n w a t e r c o m p o s i t i o n from the G o d a v a r i ri ve r c o m p o s i t i o n . All u n i t s in m g l I, except pH and conductivity.
T h e m e a n r a i n w a t e r c o m p o s i t i o n ( T D S 1 7 . 5 m g l 1) is a b o u t 1 0 % o f t h a t o f t h e m e a n G o d a v a r i w a t e r c o m p o s i t i o n a t t h e m o u t h (182 m g 1 1). T h e G o d a v a r i is p r i m a r i l y a m o n s o o n f e d r i v e r w i t h m o r e t h a n 9 5 % o f a n n u a l w a t e r d i s c h a r g e d u r i n g t h e m o n s o o n p e r i o d ( B i k s h a m , 1985). T h e r e f o r e t h e r a i n w a t e r c o m position is subtracted from the river water for rough estimation of the impact of the chemical weathering process. Based on mean chemical composition, the TABLE 6 Composition of Godavari, Indian and world river waters
pH Cond. (zS cm 1) HCO:, C1 PO 4 SO~ SiO=, Ca Mg Na K
TDS
a
b
c
7.9 319
7.7 220
7.7 339
139.4 21.9 0.12 12.9 13.7 22.7 7.7 28.5 5.7 253
104.9 16.6 0.1 7.7 9.7 22.1 5.4 12.0 3.4 182
146.9 21.4 0.1 10.2 12.0 22.8 9.5 24.3 5.1 252
d
e
74 15 12 7 30 7 12 3 161
52 9.6 0.01 8.7 10.4 13.5 3.6 7.4 1.4 106
a = discharge weighted mean; b = actual comp. at Rajahmundry (GR); c = mean of 59 samples (GM); d = mean of Indian rivers (Subramanian, 1983); e = world average (Meybeck, 1982). All units in mgl 1, except pH and conductivity.
384 TABLE 7 Dissolved ions: Relative order of abundance (in mg 1 1) Location*
Ions
GN GR PR WR PG MJ SL MN KN WG SB ID GR RW
HCQ HCO3 HCO3 HCO:~ HCO:~ HCO3 HCO:~ HCO:~ HCO:~ HCQ HCO:~ HCO:~ HCO:~ HCQ
Na Na Na Na Na Na Ca C1 Ca Ca Ca Ca Ca C1
Ca Cl C] CI C1 CI C1 Ca C1 C1 CI SiO2 C1 Mg
C1 Ca Ca Ca Ca Ca SO4 Mg Na Na SO4 CI Na Ca
SO4 SO4 SiO~ Mg Mg Mg SiO2 Na SiO~ Mg SiO~ SO4 SiO~ Mg
Mg SiO~ SO4 SiO~ SiO2 SO4 Na SiO2 K SiO2 Mg K SO4 Na
SiO2 Mg Mg SO4 SO4 K Mg K Mg K Na Na Mg SO,
K K K K K SiO2 K SO~ SO4 SO4 K Mg K SiO~
* Locations are given in Fig. 1. individual ions are a r r a n g e d in order of relative c o n c e n t r a t i o n in Table 7. Such a r r a n g e m e n t b r o a d l y indicate t h a t the G o d a v a r i River w a t e r can be grouped into two types: (a) N a H C Q C 1 d o m i n a n t water; Na is the h i g h e s t c o n s t i t u e n t of the TDS next to bicarbonate. The t r i b u t a r i e s and the m a i n G o d a v a r i d r a i n i n g t h r o u g h the D e c c a n traps (basalt) c a r r y this type of water. The high c o n c e n t r a t i o n of Na and C1 indicates their a t m o s p h e r i c origin. This type of w a t e r g e n e r a l l y has high TDS. (b) Ca HCO3C1 d o m i n a n t water; this type of w a t e r has high Ca next to b i c a r b o n a t e s and is a s s o c i a t e d with the s e d i m e n t a r y rock types.
Dissolved transport Dissolved t r a n s p o r t (solute) at v a r i o u s stations of the basin, c a l c u l a t e d from the a v e r a g e TDS (Table 4) and ten y e a r s of m e a n d i s c h a r g e (Biksham, 1985), is presented in the Table 8. The table c o n t a i n s i n f o r m a t i o n on: (a) q u a n t i t y of each c o n s t i t u e n t ; (b) rate in t km 2yr 1; (c) p e r c e n t a g e of each c o n s t i t u e n t in the solute flux; and (d) total rate of chemical erosion. F i g u r e 3 shows the down s t r e a m v a r i a t i o n in elemental c o m p o s i t i o n of the m a j o r c a t i o n and a n i o n s in the G o d a v a r i basin. The G o d a v a r i River with an a n n u a l w a t e r d i s c h a r g e of 92 km ~ t r a n s p o r t s 16.8 × 106t of solutes into the B a y of Bengal. This is a b o u t 6% of a n n u a l dissolved load from the I n d i a n s u b c o n t i n e n t ( S u b r a m a n i a n , 1979) and 0.5% (i.e 24th r a n k ) of the global dissolved flux (Meybeck, 1976). On the main G o d a v a r i River, the dissolved t r a n s p o r t shows d o w n s t r e a m i n c r e a s e from 3.1 × 106 t (Nanded) to 18.5 × 106 t (Perur). At the river m o u t h , in spite of more
385
additions by the Sabari tributary (about I × 106 t) the dissolved load decreased to 16.8 × 106t. The dissolved load of individual tributaries ranges from 0.9 × 106 t for the Manjeera to 13.6 × 106t for the Pranahita (Table 8).
TABLE
8
Dissolved flux (103 t yr River and t r i b u t a m e s Station
HCO 3
1) (a), r a t e of c h e m i c a l erosion (t km
2 yr
1) (b), and p e r c e n t a g e of each c o n s t i t u e n t (%) for the G o d a v a n
CI
PO 4
SO 4
SiO 2
Ca
Mg
Na
K
Total
1770.38 33.929 56.38 ;t249.27 31.577 55.45 106~0.68 41.048 57.63 9679.75 31.448 57.65 13556.05 44.042 58.26 325.36 1.057 21/.11 9354.40 30.391 61.65
276.14 5.152 8,79 512.83 4,984 8,75 1280.22 4.920 6,91 1527.98 4.964 9.10 1970.53 6.402 8.47 655.33 2.129 40,51 872.65 2.835 5,75
1.46 0.027 0.05 3.74 0.036 0.06 4.90 0.019 0.03 9.40 0.031 0.06 995 0.032 0.04 0.00 0.000 0.00 9,40 0.031 0.06
159.08 2.968 5.07 302.60 2.941 5.16 631.56 2.427 3.41 708.19 2.301 4.22 939.74 3,053 4.04 62.30 0.202 3.85 645.69 2.098 4.26
86.30 1.610 2.75 215.3;t 2,093 3.67 1377.12 5.293 7.4;] 898.67 2.920 5.35 1094.15 3.555 4.70 7.15 0.023 0.44 891.51 2.896 5.88
296.84 5.538 9.45 442.00 4.295 7.54 1989.30 7.645 10.73 2041.51 6.633 12.16 2103.50 6.834 9.04 302.28 0.982 18.68 1739.23 5.651 11.46
144.53 2.696 4.60 191.25 1.859 3.26 673.74 2.589 3.64 501.78 1.630 2.99 878.57 2,854 3.78 117.68 0.382 7.27 384.09 1.248 2.53
342.76 6.395 10.92 810.33 7.875 13.83 1502.52 5.774 6.11 1105.92 3.593 6.59 2244.45 7.292 9.65 66.92 0.217 4.14 1039.00 3.376 6.85
62.53 1.167 1.99 132.88 1.291 2.27 393.30 1.512 2.12 317.18 1.030 1.89 471.36 1.531 2.03 80.76 0.262 4.99 236.41 0.768 1.56
3140.01 56.582 100.00 5860.24 56.951 I(X).00 18533.32 71,227 100.(X} 1679038 54.550 I(X).00 23268.30 75.596 100.00 1617.79 5256 1(X).00 15172.59 49.294 I(X).(X}
7891.19 72.529 58.05 2666.48 66.662 t;4.40 745.20 40.500 63.70 19115.48 53.675 65.37 1793,30 42.698 51.73 552,36 34.523 61.38 131/.17 21.508 43.35
1225.06 11.260 9.01 321.09 8.(}27 7.75 79.95 4.345 6.83 196.71 5.541 6.75 249.70 5.945 7.20 88.38 5.524 9.82 110.19 5.509 11.10
5.74 0.053 0.04 1.30 0.032 0.03 0,42 0.023 0.04 3.16 0.089 0.11 0.45 11.011 0.01 0.20 0.013 I).02 0.92 0.046 0.09
550.38 5.059 4.05 123.71 3.093 2.99 11.5 0.628 0.99 7.90 0.223 0.27 170.25 4.054 4.91 31.50 1.969 3.50 98.25 4.912 9.2)
828.75 7.617 6.10 165.4l 4.135 3.99 30.75 1.671 2.6;t 67.15 1.892 2.39 ;{06.45 7.296 8.84 16.32 1,020 1.81 92.28 4.614 9.30
898.87 8.262 6.61 260.;t9 6.510 6.29 107.85 5861 9.22 465.31 13107 15.,(Xi 681.00 16.214 19.64 63,06 3941 7.01 145.47 7274 14.66
470.69 4.326 3.46 176.07 4.402 4.25 61.50 3.342 5.26 102.70 2.893 3.52 27.24 0.649 0.79 37.92 2.37(I 4.21 47,22 2.361 4.76
1466.25 13.477 10.79 368.35 9.209 8.90 117.30 6.375 10.03 t25.61 3.538 4.31 113.50 2.702 3.27 92.16 5,760 10.24 33.9;t 1.696 3.42
256.06 2.354 1.66 57.92 1,448 1.40 15.;30 0.832 1,31 41.1/8 1,157 1.41 124.85 2.973 3.60 18.iX) 1,125 2.00 33.93 1.696 3.42
13592.99 I24.936 1(X1.00 4140.72 103.516 100.00 1169.82 63.577 ]/10,00 2915.10 82.115 11X)90 3466.74 82.542 l(g)./)0 899.90 56244 1(X1.00 922.;15 49.617 I(X).911
G o d m ari R i t er
GN
GK
(]P
(]R
GM
RW
Diffofence*
a b % a b % a b % a b % a b % a b '% a b %
Tributaries
PR
WR
PG
WG
ll)
MJ
SB
a b %, a I) % a b % a b '% a
h ", a 6 % a b %
Legend: GN Godavari-Nanded; GK Godavari-Kaleshwaram; GM M e a n of 59 samples; RW rain water; PR P r a n a h i t a ; WR dravathi; M J M a n j e e r a : SB Sabari.
GP Godavari-Perur; GR Godavari-Rajahm u ndry: W a r d h a : PG P e n g a n g a ; WG W a i n g a n g a ; lI) In
* After deducting the rain w a t e r composition from the Godavari River composition.
386
Elemental fluxes Inorganic carbon accounts for about 25% of total transport at most of the sampling locations except for the Sabari (17%). The rate of carbon transport is around 6t km-2yr 1. But for some tributaries flowing through deccan traps (basalt) the value is up to 14 t km 2yr 1. Since the dissolved organic carbon (DOC) in rivers is important (DOC = 10ppm, Meybeck, 1982), the values for inorganic C given here represent the lower limit of the total carbon transport in the Godavari. The C1 transport of the Godavari is around 1.5 x 10~t yr with a rate of 5 t km ~yr- ~. The maxium rate for C1 (11 t km 2yr ~was observed for the Pranahita subbasin, which can be understood in terms of high C1 content in rain water in this part of the basin (Table 8). The Godavari (a) (a)
106 tonnes krn2/yr
,,'~,~.-p 10 6 t o n n e s --~ t / k r n 2 / y r
CHLORIDE
"~
103 tonnes . Kg/krnL/yr
PHOSPHORUS
~
"-'~:~/
.,:6~ (' 00~
~
SULPHUR
103 t o n
m2/yr
SILICO N
~
,f'a~.--P 106 t o n nes ~ t/km2/Y r
387 ,"S'~'~ lO3 tonnes
b)
~ ~L" ilk rn2/yr (u.,,,
,orn, ,or o,,
POTASSIUM
'
~
rC.
CALCIUM
M2"~AGN ESIUM Fig. 3. Elemental variation. (a) Among major anionic constituents; (b) among major cationic constituents. transports around 253,000 t of sulphur yr 1 at a rate of 0.8 t km 2yr 1, ranging from 1.7t km ~yr -1 (Pranahita) to 0.07t km 2yr 1 (Wainganga). Similarly, the Godavari transports 270,000 t of Si at a rate of 0.9 t km 2yr 1. The four major cations (Ca, Mg, K, Na) account for about 56% of the total elemental fluxes. The transport of Ca is highest among these four at 6.5 t km ~yr 1. For the other elements, Mg, Na and K, the rates are 1.6, 3.6 and 1.0, respectively. Calcium mobility is higher from the rivers draining the granitic terrain, whereas Na is higher in the Deccan traps region. The rate of erosion for K is more or less uniform except for the Indravati and P r a n a h i t a (around 3t km 2yr 1). The tributaries flowing through Deccan traps (Pranahita and Wardh) contribute Mg three times the average for the entire basin. Figure 3 shows the downstream variations in individual solute transport. The rates for C1, K, S and Si are more or less uniform. Ca and C show increase at mid basin (GP) and drop at the river mouth. A steep decrease of Na and a slight decrease of Mg below Kaleshwaram is also evident from the figures. Geology as a controlling factor Table 9 summarises the lithological control on the river water chemistry. The tributaries and main river flowing through the Deccan traps (with 48% of basin area) contribute more than 85% of the dissolved load while the remaining 15% is contributed by Sabari and Indravati, flowing through granites and other
388 TABLE 9 Contribution to elemental dissolved load by geological units Element
a
b
a + b
c
(~ C] P S Si Ca Mg Na K
2230 1737 3.12 282 313 1341 662 2276 389
442 360 0.18 88 120 827 74 147 159
2672 2097 3.30 370 440 2168 736 2423 548
1936 1527 3.10 233 270 2042 501 1105 317
d
e 736 570 0.20 137 170 126 235 1318 231"
28 27 6 37 39 5 32 54 42*
a Deccan traps; b = granites and other hard rocks: c = Out flow at river mouth; d = Quantity retained by sedimentary rocks: e = Percentage of dissolved load retained/contributed (*) by sedimentary rocks. Figures in 10:~tyr ~. hard rocks. The s e d i m e n t a r y rocks (7% of basin area) located in the lower part of the basin do not c o n t r i b u t e a n y significant q u a n t i t y of the solute load to the basin. At R a h j a m u n d r y (GR) the river delivers 16 x 106t of solute load. The depletion of individual ions in the s e d i m e n t a r y rock area r a n g e s from 5% of inflow (Ca) to 54% (Na). Above the s e d i m e n t a r y rock area the river carries 23 x l0 Gt of solute load, and loses 7 x 10Gt d u r i n g passage t h r o u g h the 200 km r e a c h of s e d i m e n t a r y terrain. The depletion of 7 x 10~t of dissolved elements in these s e d i m e n t a r y rocks m a y possibly be due to the selective ionic e x c h a n g e from the river w a t e r to the sediments. These s e d i m e n t a r y r o c k s c o n t r i b u t e 56 x 10Gt of suspended sediments to the river t r a n s p o r t total of 170 x 10~t yr 1 (Biksham, 1985). M i n e r a l o g i c a l studies at the river m o u t h indicated t h a t more t h a n 60% of clay f r a c t i o n of these sediments were m o n t m o r i l l o n i t e (Biksham, 1985). The large a m o u n t (1.3 x 10~t, or 54% of input) of sodium r e t a i n e d in this r e a c h indicates t h a t the clays after some selective ionic e x c h a n g e m a y have become Na montmorillonites.
Variation in solute transport The q u a n t i t y of a n n u a l dissolved t r a n s p o r t (Td) of the river varies m a i n l y depending on the q u a n t i t y of discharge. An a t t e m p t is made here to elucidate the r e l a t i o n s h i p between discharge and the solute t r a n s p o r t based on the available d a t a (Table 10). The a n n u a l Td varies by a f a c t o r of 3.6 from 8.2 to 29.2 x 106t in the 10-year period, whereas the d i s c h a r g e (Q) v a r i a t i o n f a c t o r over the c o r r e s p o n d i n g period is only 1.6. M o n t h l y v a r i a t i o n s are quite signific a n t (Table 11) and they suggest the following points: (a) more t h a n 87% of the a n n u a l Q and Td are t r a n s p o r t e d d u r i n g t h r e e m o n t h s (July, A u g u s t and September) and d u r i n g the same period 99.6% of the a n n u a l sediment load is t r a n s p o r t e d : (b) except for three months, the chemical load (Td) is more t h a n
389 TABLE 10 A n n u a l v a r i a t i o n of dissolved t r a n s p o r t Year
1969 70 1970 71 1977 78 1978 79 [979 8(} Mean
Q
TDS
Td
(km3yr ~)
(mgl 1)
(1060
Mean (106t)
95 104 87 121 66 94.5 92.3*
237 ~ 280 b 230 c 178 ~ 125 ~ 210 161
22.5 29.2 20.0 21.5 8.2 20.3 16.8
21.8 25.8 21.2 16.4 11.5 19.4 16.8
Td *
' Mean of eleven, and bsix m o n t h s data (unpubl. reports, CSMRS, 1973). ' Mean of two (seasons) samples, p r e s e n t study. '~Mean of ten years data, CWC. * Based on respective years TDS and mean Q of ten years.
the sediment load (Ts), and the ratio of Ts/Td varies from 14.7 (August) to 0.05 (January) with an annual average of 11.8; (c) the TDS increases with discharge; (d) the discharge weighted mean annual TDS (227 mgl -]) is very close to the mean for the monsoon seasons (226mgl 1); (e) the annual Td estimation, l
74
I
76
I
I
78
i
80
82
814
I
22!
C"
i i
L_j.,.,.
f
,o_ Nx
4~
~,!
INDRAVATI
-18
"-~, ..,. ~
'ok ~
g
250 K m
_16°W
,ire
',+
?
Fig. 4. Solute erosion rate v a r i a t i o n in the Godavari Basin.
82 I
B4 I
+
390 TABLE 11 Monthly variation of mass transport (1969 70) Month
Q (10~m :~)
Td ( TDS ) (103 t)
Ts ( T S M ) (mg 1 ~)
Ts/ T d
June July Aug. Sept. Oct. Nov. Dec. Jan. Feb. March April May Annual
730 17,300 30,030 35,900 4,550 2,700 1,500 870 570 520 390 370 95,460
160 2,800 4,260 11,790 950 700 340 200 135 130 120 100 21,690
75 32,510 50,880 173,500 750 142 20 10 10 56 50 60 257,900
0.5 11.5 11.9 14.7 0.8 0.2 0.06 0.05 0.07 0.4 0.4 0.6 11.8
(219) (162) (142) (328) (209) (259) (227) (230) (236) (250) (308) (270) (227)*
(103) (1879) (1695) (4832) (165) (53) (13) (12) (8) (11) (13) (16) (2702)*
Q ~ water discharge (103m3); T d = dissolved load; Ts - suspended load. * Discharge weighted mean.
16.8 × 106t might be slightly reduced if annual TDS values (not available) were weighted against respective annual discharge; and (f) the highest TDS and TSM correspond to the highest discharge month (September). Figure 4 shows the variations in solute fluxes throughout the Godavari basin.
Atmospheric input The dissolved transport of continental rivers includes a significant quantity of atmospheric contribution through rain water and aerosol particles. Such atmospheric contributions should be subtracted in arriving at the actual rate of chemical erosion over the river basins (Meybeck, 1983; Holland et al., 1986). An attempt is made herein to estimate the atmospheric input over the Godavari basin based on four rain water samples. The composition of these samples (TDS 17.6 mg 1 1) is in broad agreement with rain water from the other parts of India (Handa, 1968, 1972). The annual contribution of dissolved salts by rain water over the basin are estimated based on rainfall of 1185mm yr 1 (Indian Meteorology Department reports). The amount of rain water input over the basin is around 370 km ~, which is nearly four times the annual runoff of the Godavari River (92 km2). Table 12 summarises the various components of mass balance of solute transport in the basin. Overall the atmospheric input over the Godavari basin is 37% of solute transport of the river. For the individual ions, HCO3, SO4, Na, Ca, Mg, and K it amounts to 13, 29, 25, 59, 94 and 100% of river output, respectively. This broadly indicates the cyclic nature of the many ions in river transport, which is very significant for estimating chemical erosion.
391 TABLE 12 Chemical mass balance over the Godavari Basin Ion
HCO:~ CI SO 4 SiO,, Ca Mg Na K Total
Water composition (mg 1 1)
Mass transport (t km 2yr i)
Godavari, rain
India mean, rain
Godavari, mean
Rain
River
Sun
3.5 7.1 0.7 0.1 3.3 1.3 0.7 0.9 17.5
7.0 6.0 1.7 0.8 2.9 8.5 1.3 0.6 28.9
104.8 16.6 7.7 9.7 22.1 5.5 12.0 4.9 181.9
4.8 8.4 0.8 0.1 3.9 1.5 0.9 1.0 20.8
31.5 5.0 2.8 4.8 6.6 1.6 3.6 1.0 56.9
36.3 13.4 3.6 4.9 10.9 3.1 4.5 2.0 77.7
Rain contr. (%)
13 63 22 2 36 48 20 50 27
Figures are rounded to the nearest digit/number. REFERENCES Abbas, N. and Subramanian, V., 1984. Erosion and sediment transport in the Ganges River basin, India. J. Hydrol., 69: 17~182. Biksham, G., 1985. Geochemistry of the Godavari River basin. Ph.D. Thesis, Jawaharlal Nehru University, 265 pp. (unpubl.). Biksham, G. and Subramanian, V., 1980. Chemical and sediment mass transfer in the Godavari River basin in India. J. Hydrol., 46: 331--342. Carbonnel, J.P. and Meybeck, M., 1975. Quantity variations of the Mekong river at Phnompenh, Cambodia and chemical transport in the Mekong basin. J. Hydrol., 27:249 265. Conway, E.J., 1942. Mean geochemical data in oceanic evolution. Proc. R. Irish Acad., 48:119 159. Davis, S.N. and Dewiest, R.J.M., 1962. Hydrogeology. Wiley, New York, N.Y., 463 pp. Ericson, E., 1960. The yearly circulation of chloride and sulphur in nature, meteorological, geochemical and pedological implications, part II. Tellus, 12:63 109. Garrels, R.M. and Mackenzie, F.T., 1971. Evolution of sedimentary rocks. Norton, New York, N.Y., 339 pp. Gibbs, R.J., 1967. The geochemistry of the Amazon River system, Part I, The factors that control the salinity and composition and concentration of suspended solids. Geol. Soc~ Am., Bull., 78: 1203 1232. Gibbs, R.J., 1972. Water chemistry of the Amazon River. Geochim. Cosmochim. Acta, 36:1061 1066. Handa, B.K., 1968. Chemical composition of rain water over Calcutta. Indian J. Meteorol, Geophys., 20: 150-154. Handa, B.K., 1972. Geochemistry of the Ganges River. Ind. J. Geohydrol., 13:71 78. Holland, H.D., Lazer, B. and McCaffrey, M., 1986. Evolution of the atmosphere and oceans. Nature, 320:27 33. Hui, H.M., Stallard, R.F. and Edmond, J.M., 1982. Major ion chemistry of some large Chinese rivers. Nature, 298: 550-553. Livingstone, D.A., 1963. Chemical composition of rivers and lakes, data of geochemistry. U.S. Geol. Surv., Prof. Pap., 440-G, 64 pp. Meybeck, M., 1976. Total dissolved transport by world major rivers. Hydrol. Sci. Bull., 21:265 289. Meybeck, M.. 1982. Carbon, nitrogen and phosphorus transport by world rivers. Am. J. Sci., 282: 401 450.
392 Meybeck, M., 1983. Atmospheric inputs and river transport of dissolved substances. Dissolved load of rivers and surface water quantity/quality relationship. Proc. Hamburg Symp., IAHS, Publ. No. 141. Ray, S.B., Mohanti, M. and Somayajulu, B.L.K., 1984. Suspended matter, major cations and dissolved silica in the estuarine waters of Mahanadi River, India. J. Hydrol., 69:183 196. Reinson, G.E., 1976. Hydrogeochemistry of Genog River basin, N.S. Wales and Victoria. Australian J. Mar. Fresh Water Res., 27:165 -185. Sarin, M.M. and Krishnaswamy, S., 1984. Major ion chemistry of Ganga Brahputra river systems, India. Nature, 312: 538-541. Stallard, R.F. and Edmond, J.M., 1981. Geochemistry of the Amazon 1. Precipitation chemistry and the marine contribution to the dissolved load at the time of peak discharge. 3. Geophys. Res., 86: 9844-9858. Stallard, R.T. and Edmond, J.M., 1983. Geochemistry of the Amazon - 2. The influence of geology and weathering environment on the dissolved load. J. Geophys. Res., 88:9671 9688. Subramanian, V., 1979. Chemical and suspended sediment characteristics of rivers of India. J. Hydrol., 44:37 55.