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

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temporal and lateral variation. Temporal variation includes hourly daily and seasonal changes as a result of tide wind and weather making the system a thoroughly dynamic one. If mixing is not effective stratification occurs and a vertical salinity gradient develops. Estuaries and similar marginal marine environments are the principal places where the two major types ofearth -surface water meet: fresh land derived water and the saline ocean water. A schematic ofestuarine processes is shown in figure 1.5. Suspended matter which is chemically equilibrated with fresh water is carried by rivers and, upon subjection to a series ofchanging salinities and pH changes within the estuary, undergoes chemical reactions. This often causes precipitation of the suspended matter by flocculation and / or aggregation. Additionally there are chemical changes between the suspended sediment and the estuarine water that change the chemistry of both. Besides the mixing of fresh and saline water in the estuaries, there are internal processes within the estuary itself that can change the chemical composition of the water (Berner, 1987). Exchange of both dissolved and particulate matter occurs between the sediments of the bottom of the estuary and overlying water. In addition, considerable biological activity occurs in the estuarine water in the surrounding tidal marshes and in the bottom sediments. Nutrients are cycled biologically within the estuary (C,N,P,Si) and as a result dissolved and particulate organic matter are both produced and consumed. Man causes changes in estuaries both in the amount and type of suspended sediment and ofdissolved material reaching the estuaries through the rivers and land run offfrom surrounding urban and rural areas. Nutrients are particularly affected by pollution, and estuaries, because they retain water for appreciably long periods, can become eutrophic. A schematic of coastal eutrophication process is shown in figure 1.6. There is also concern about trapping of anthropogenic trace metals in estuaries. 13
Salinity intrusion is the most significant factor in the bio-chemical processes and ecological patterns in the coastal aquatic environment. The migration of salinity happens in the midst of a continuous tussle between run off and tidal push. To a lesser degree, density gradient, frontal eddies, wind surges, Coriolis force and turbulent mixing influence the conservative cycle ofthe migration ofsalinity (Zann, 1995). As long as the discharge momentum offresh water is sufficient to keep sea water at a bay the tidal canal remains fresh. And the ubiquitous tidal bulges, instead of pushing the saline water upstream, spends itself in bulking. When precipitation grows thin and run off slackens a tongue of saline water moves upstream with the active and intermittent support of tides. Strong tidal forces push salinity upriver beneath the out flowing river water. The turbulence caused by these tidal forcing results in resuspension of sediments and other particulate material present on the river bed. Concurrently dissolved material in the river water flocculates when it comes into contact with salt wedge. The combination of these two processes results in elevated levels of suspended particulate matter- the estuarine turbidity maximum (ETM). Within the region of the ETM material in the water column and in bed ofthe estuary, is trapped, resuspended and advected. The strength and distance ofETMdepend on tidal phase and river discharge. But the chemistry ofthe water column alone is not responsible for cases of algal bloom especially in the case of shallow water embayments. Diffusion, resuspension, macrophyte translocation and the regular migration between the water column and the sediments can result in significant transfer ofnutrients from the sediments to the water column. The tidal dynamism imparts a time variable mixing through frictional interaction with bottom and overlying fresh water flows and a spatially asymmetric flow pattern through interaction with bottom topography, resulting in a, residual circulation pattern of small magnitude but great persistence, patterns that play a significant role in the transport ofpollutants. (Martin and McCutcheon, 1999) 14
Page 1 and 2: Salinity Intrusion and Seasonal Wat
Page 3: IV Table of Contents LIST OF TABLES
Page 6 and 7: 11 III IV V VII List of Tables Tabl
Page 8 and 9: III IV V IX Fig 3.1 Classification
Page 10 and 11: hI. were found to be creeks extendi
Page 12 and 13: 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: Responses Reversible Direct Respons
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 92 and 93:
influences chemical process like so
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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