Salinity Intrusion and Seasonal Water Quality Variations in the Tidal ...

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influences chemical process like sorption-desorption and flocculation as well as physical process like vertical mixing, stratification etc. which in turn influence the distribution and speciation of many trace elements. The level of salinity also influences the survival of fresh water microbes. The concentration of various cations and anions being constant in sea water, the degree of dilution of sea water with fresh water in the tidal canals is reflected in the chloride concentration. Any deviation in the dilution factor in the case of non conservative dissolved chemicals sheds some light into the physico-chemical changes that salinity intrusion becomes the platform for. Chloride in sea water is around 19000mg/L and in fresh water it is around 10-40 mg/L depending on anthropogenic inputs. Hence chloride levels, being a conservative ingredient, register the degree of dilution within reliable margins. But if chloride level is the indicator of dilution, the calcium concentration in the canals is at least two times more than the Calcium ions entering from the seas. Hence precipitation of calcium as calcium phosphate, if at all, does not rise to very high levels. Iron in sea water is less than 20Jlg/L. Hence total Fe appearing in the water bodies is entirely from terrestrial wash out in which economic activities make up a major share. Soluble phosphate, though a major plant nutrient, does not go beyond 30Jlg/L in the surface layers of the sea water. This fact implies that sea water does not add to P04 3 -levels in the tidal canals. Phosphate concentration sharply falls in the initial stages of salinity intrusion in December-January, because of dilution of sewage rich water body with sea water and a dramatic rise in photosynthetic activity. Phosphate steadily rises thereafter because of the accumulation of sewage as natural flushing is 62
not effective during the dry months. Therefore, in the lean months, primary effect of sea water intrusion is dilution ofphosphates followed by accumulation due to subdued flushing. Thus the governing process is physical than chemical. It can safely be assumed that pH and salinity levels should cross a threshold which could potentially trigger salt water induced chemical reactions bringing about a shift in the chemical environment comparable to the patterns spelt out in the introduction. In water logged regions and in places where natural drainage is ineffective or stalled, salinity will persist, irrespective of the season of the year. In the case of tidal canals where the flux is not severely impeded, migration of salinity is essentially seasonal and is decided by runoff and tidal impact. Urbanization confounds the situation because of lightning floods and diminished residual flow. In the light of the data obtained across the water year 2003-2004, the saline pendulum characteristic of each canal of the city is spelt out in the pages to follow. Annual precipitation and its distribution being invariable within reasonable margins, the tidal fingerprint and human intervention alone are the deciding factors in the salt-water migration phenomenon. The time frame given in the data below is subject to small variations given the vagaries of monsoons. During the sampling year, for example, North East Monsoon was comparatively very weak and sporadic. Though samples were collected from the surface it has been pointed out by Mishra et al., (2003) from their studies held in the coastal waters of Orissa, that phosphate and nitrate have a proclivity of concentrate at the bottom Perhaps the most important environmental problem that the water bodies of the city are nagged by is deficiency of DO. With improved DO, the whole chemical 63
Page 1 and 2:
Salinity Intrusion and Seasonal Wat
Page 3:
IV Table of Contents LIST OF TABLES
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11 III IV V VII List of Tables Tabl
Page 8 and 9:
III IV V IX Fig 3.1 Classification
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hI. were found to be creeks extendi
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XIII The study embodied here is par
Page 14 and 15:
1.1 Fresh water as a natural resour
Page 16:
taught us to value fresh water more
Page 20 and 21:
Source: Keller (1984) .... There is
Page 22 and 23:
The role played by water as a solve
Page 24 and 25:
3. Commercial water supplies 4. Was
Page 26 and 27:
The status report presented above d
Page 29 and 30:
Responses Reversible Direct Respons
Page 31 and 32:
Salinity intrusion is the most sign
Page 34 and 35:
eaches 15 g/kg. Work by Boyle, Edmo
Page 37 and 38:
Cd. The .removal of phosphate may o
Page 39 and 40:
1. Dissolution nutrients from parti
Page 41 and 42: unpolluted estuaries left and most
Page 43 and 44: The design, according to Maxted et
Page 45 and 46: that the water biotic quality did n
Page 47 and 48: nutrient load was predictive but co
Page 49 and 50: For a city fast growing, as in the
Page 51 and 52: CHAPTER 2
Page 53 and 54: 2.1 The study area Chapter 2 MATERI
Page 55 and 56: salinity and the trapped water bodi
Page 57: 2.2 Cochin and the back water lagoo
Page 60 and 61: Cochin originally developed as a co
Page 63: 400,000 commutes to the city from t
Page 67 and 68: disparity. Such an engineering modi
Page 69: 4. Mullassery canal: (Figure 2.7) T
Page 73: 11. Poornipuzha:(Figure 2.10) It is
Page 76 and 77: are two fresh watercourses ending u
Page 78 and 79: Cochin Corporation records, there a
Page 80 and 81: 2. Poorni River - Konnara thod - Pa
Page 82 and 83: 8. KSEB-International Stadium (clos
Page 84 and 85: 9 Perumpadappu kayal 3 10 Kumbalang
Page 87 and 88: Onceback in the laboratory, where r
Page 89: pH was chosen as a regular paramete
Page 95 and 96: salinity pattern is applicable to t
Page 97 and 98: ecorded on 9 th March. The Ambalapp
Page 99 and 100: or even equal to that of the sea wa
Page 101 and 102: the latest engineering modification
Page 103 and 104: ThripoonithuraMunicipality's waste
Page 105 and 106: 4 Chithrappuzha- Water doled out fr
Page 107 and 108: 6 Mullassery Canal whole is flood p
Page 109 and 110: a deleterious effect on the quality
Page 111 and 112: - Adimury the railroad to Kaloor is
Page 113 and 114: June. Phosphate Increases until tim
Page 115 and 116: 12 Punchathod- Kharee thod the anal
Page 117: ocearnc ongm, But Phosphate level r
Page 120 and 121: COD(nlglL) 73.4 103.3 243.1 COD(mgl
Page 122 and 123: TH(mg CaC03/L) 64.7 186.4 443 TH(mg
Page 125 and 126: TH(mg CaC03/L) 114.6 1334.3 3480 TH
Page 127 and 128: TH(mg CaC03/L) 118.8 2489.4 9800 TH
Page 131 and 132: 60 50 40 20 10 o WOI Fig 3.198WQI o
Page 133 and 134: As Figure 3.198 depicts water quali
Page 135 and 136: Table.3.87 Classification of water
Page 137 and 138: The only tidal body where the seaso
Page 139 and 140: violently multiplies wherever the c
Page 141 and 142: than 61mg/L. Falls in alkalinity co
Page 143 and 144:
is an exception as phosphate follow
Page 145 and 146:
sweep the earth following the sun a
Page 168:
500 350 150 100 50 90 80 70 60 20 1
Page 251:
CNP StoIchioIlleQr6 --••_.--t N
Page 257:
DIN. 121 4.2.1.5 Stoichiometric der
Page 260:
olume Surface flo 124 oxes. Vx is a
Page 275:
138 February 0.02 0.01 392 11.7 31.
Page 284 and 285:
CHAPTER 5
Page 286 and 287:
145 depletion in the canals. Again
Page 288 and 289:
147 7 Arius "Plastistomus 50 Megalo
Page 290 and 291:
149 5.3.1 Canals heavily polluted a
Page 293 and 294:
151 deweeded and maintained well, e
Page 295 and 296:
All points but Panar and Karingachi
Page 297 and 298:
West Cochin Wholestretch 155 Whole
Page 299 and 300:
Edappally thod - whole stretch abov
Page 301 and 302:
159 At present, the water is not fi
Page 303:
161 effective aeration to the putri
Page 307:
174 45. Flemer. Potential sediment
Page 311:
178 107: Pritchard DW. What is An E
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