Impact Of Floods In Low Lying Areas Environmental Sciences Essay

Vijayawada city is situated on the banks of river Krishna. Floods affect the city many times, which creates damage to the people and properties. The city has faced many floods since long back. The aim of the study is to find out the factors which are responsible for the floods in the city and the impact of the floods in the low lying areas (which are mostly affected) of Vijayawada. This study will be useful to work out the measures to handle the floods in the city. A few suggestions have been given to tackle the damaging phenomenon of the floods.

Keywords: Vijayawada, Krishna River, Budameru canal, Floods,

INTRODUCTION:

Vijayawada is the third largest city in the state of Andhra Pradesh. Over the years, Vijayawada has been experiencing extensive development coupled with high urban growth. It is an important commercial and transport centre of the State. Being a big city people from all over the country are migrating to Vijayawada for their livelihood irrespective of their caste and creed. The rapid urbanization in the city has led to increase the problem of settlements with the unsafe locations which ultimately causes natural disaster. In addition to this, heavy rains in this area have been causing frequent floods with roads in many places submerged for several hours and the road traffic coming to a halt, bringing in considerable damage to public and private properties. Floods are the most damaging phenomena that effect to the social and economic of the population. It is one of the major disasters affecting the population especially those living in high risk areas, in the flood plains and the low lying areas causing extensive damage to properties and even loss of lives.

But before studying the impact of the floods in the low lying areas of Vijayawada, let us first understand the meaning of Floods.

A Flood is an overflow of water that submerges land. The European Union (EU) Floods Directive defines a flood as a covering by water of land not normally covered by water. Flooding may result from the volume of water within a body of water, such as a river or lake, which overflows or breaks levees, with the result that some of the water escapes its usual boundaries, or may be due to accumulation of rainwater on saturated ground in an aerial flood

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Floods are caused by many factors: heavy rainfall, highly accelerated snowmelt, severe winds over water, unusual high tides, tsunamis, or failure of dams, levees, retention ponds, or other structures that retained the water. Flooding can be exacerbated by increased amounts of impervious surface or by other natural hazards such as wildfires, which reduce the supply of vegetation that can absorb rainfall. The factors which are responsible for the flooding of Vijayawada city will be studied in a detailed manner in the following study.

TOPOGRAPHY OF THE CITY:

The city is sited at the foot of a low range hills on the northern bank of the river Krishna with its cardinal points as 16° 31′ North latitude and 80° 37′ East longitude, around 70 km away from the coast.

The land lay of Vijayawada is characterized by four canals, four hills and the river Krishna. Vijayawada when approached from Guntur is welcomed by the historic gates across the holy river Krishna. The way to Machilipatnam runs parallel to Budameru canal and crosses two other canals.

There are four major hills:

a) Indrakiladri Hill

b) Machavaram Hill

c) Gunadala Hill

d) Moghalrajapuram Hill

The natural slope of the old town is falling from north to south whereas the new town slopes down from west to east. When compared to the old town, the new town is flat and hence makes drainage less effective. Though the city is protected from high flood banks in the southern side, the low-lying lands are not immune to floods.

Indrakiladri hill (One town & Vidyadharapuram):-

The areas covered by Indrakiladri hill are popularly known as I Town and Vidyadharapuram. It is located on the West Side and Northern Side of Vijayawada City. The height of the hills is about 240 Meters. The perimeter of the hills is about 10 km. The areas such as Ramarajaya Nagar, Kummaraalem, 4-Pillar center, Ali Nagar, Kabela Road are falling with in this hill area.

Mogalrajapuram hill

Mogalarajpuram Hills of Vijayawada is a major hill range located on the Eastern side of Vijayawada city. The maximum height of the hills is about 250 Meters. The perimeter of the hills is about 6 kms. The areas such as Dasari Ramana Nagar, Ravi Chettu Center, Sunnapubattila Center are falling within these hill areas.

Machavaram hill

Machavaram Hills of Vijayawada is a major hill range located on the East Side of Vijayawada City. The maximum height of the hills is about 240 Mts. The perimeter of the the hill area is about 4 km. The areas such as Karimkanagar, Gulammohiddin Nagar, Maruthinagar are falling within these hill areas.

Gundala hill

Gunadala Hills of Vijayawada is a major hill range located on the Eastern Side of Vijayawada city. The maximum height of the hills is about 242 Meters. The perimeter of the hills is about 10 km. The areas such as Ayyapanagar, Kristurajapuram, Vijayanagar Colony, Arunlagar, Lurthnagar, Betlahem Nagar etc. are falling within these hill areas.

Source of the Information: MRO (Urban), Revenue Dept, Vijayawada.

Canals:-

The Krishna Eastern Main Canal on the left bank of Krishna River, after traversing for one km gets divided into three canals; Eluru canal, Bandar canal and Ryves canal traversing the inner city. Apart from these, Budameru stream skirts the city limits to pass through the rural part of the VMC.

Bandar Canal

The canal traverses for a distance of 7.5 km on the southern side of the city. For free movement of traffic, the canal has 10 bridges built across it.

Ryves Canal

The canal flows for a distance of around 7.6 km on the north-eastern side of the city. There are about 8 bridges across it.

Eluru Canal

The canal runs for a total distance of around 65 km in Krishna and West Godavari districts. There are about six road bridges, two railway bridges and two foot-over bridges across the canal.

Land Use Profile

The city area can be broadly divided into two categories – one ‘Developed area’ and the second ‘Undeveloped area’. Of the Vijayawada corporation area of 6188 ha, the developed land part of the city covers 3753 ha accounting for around 61% of the city area, leaving 2435 ha undeveloped.

Land Use Composition: Vijayawada, 2004

S.No

Land Use

Area in Ha.

% to developed

area

% to total area

Developed component

1.

Residential ( Built -up )

1348.25

35.92

21.79

2.

Mixed-Residential ( Built -up )

141.36

3.77

2.28

3.

Residential vacant plots

229.02

6.10

4.11

4.

Commercial

247.91

6.6

4.01

5.

Industrial

72.38

1.93

1.17

6.

Public & Semi- public

270.16

7.2

4.37

7.

Institutional

178.31

4.75

2.88

8.

Parks & Play grounds

60.34

1.60

0.56

9.

Recreational / Others

3.1

0.08

0.05

10.

Roads

800.81

21.34

12.94

11.

Railway

190.49

5.08

3.08

12.

Water Bodies ( Canals & Others)

211.26

5.63

3.41

Sub Total

3753.39

100

60.65

Un-Developed component

13.

Agricultural Area

885.97

36.40

14.32

14.

Vacant Lands

618.27

25.39

9.99

15.

Water Bodies ( River)

668.42

27.45

10.80

16.

Hills

262.06

10.76

4.23

Sub Total

2434.72

100.00

39.35

Grand Total

6188.11

100.00

100.00

Source: VGTMUDA

Rivers and Dams

There are two rivers flowing from Vijayawada

Krishna River

Budameru river/Drain which creates havoc during rainy season.

Krishna River

The River Krishna takes of its origin in the Western Ghats at an elevation of (+) 1336 Mts and runs for a length of about 1400 km and runs through Vijayawada city and joins at Bay of Bengal. The length of Krishna River up to Prakasam Barrage is about 1310 km. The flow of the river is managed partially by the Nagarjuna Sagar dam which is located to the west of Krishna District and Prakasam Barrage which is located at the beginning of the city.

The Krishna Flood bank Above Prakasam Barrage is about 13km and below flood bank is 6.40 km which creates havoc in flood season which starts from June to December. Water release from barrage with 4, 12,734 to 10, 94,422 Cusecs is been observed over the years.

Dam management

Since the main purpose of the dam is to provide irrigation, the dam authorities try to fill the reservoirs during the monsoon to ensure water availability for the farmers in the surrounding districts during summers. Therefore occurrence of severe rainfall (1 day or 2 day extreme precipitation) due to cyclone or depression during the latter half of the monsoon season in the lower and middle Krishna basin leads sudden increase in the reservoir level forcing the dam authorities to release water which sometime exceeds the carrying capacity of the river. This leads to flooding along the downstream.

Flood Banks

The total length of flood bank in Krishna District (within which the Vijayawada city is located) is 226.98 km. The flood banks of the River Krishna were originally formed in 1892. The flood banks were provided on both sides of the River up to sea as detailed below to contain the flood water with in the flood banks and there by protect the properties and human lives etc in Krishna District.

Details of Flood Banks in Krishna District

S.No.

Details Of The Flood Banks

Length In km

1.

Krishna Left flood bank

(above Prakasam Barrage)

13.00

2.

Krishnalanka Flood bank

(below Prakasam Barrage)

6.40

3.

Krishna Left flood Bank (below Prakasam

Barrage)

89.60

4.

Divi Left flood bank

36.00

5.

Divi Right Flood Bank

32.00

6.

K.E. Tidal Bank Divi Island

22.00

7.

Kona Tidal Bank (Machilipatnam Side)

18.50

8.

Seadyke Flood Bank (Machilipatnam Side)

2.50

9.

West Side Flood Bank (Machilipatnam

Side)

6.00

10.

Rudravaram Flood Bank (Machilipatnam

Side)

4.00

Total

230.00

Source: Irrigation Dept

Krishna Lanka Flood Bank: (3.38 km): This flood bank was formed during 1967 to protect the residents of Krishnalanka of Vijayawada city.

Embankments /Flood Bank locations

S.No

Name of the

Embankment

Length of the

Embankment in km

Area covered

Length of the

Embakment within the ward

1

Krishna Left Flood Bank(Above Barrage) From ( Ibrhimpatnam

to Prakasham Barage)

13km

IbrahimPatnam to

BhavaniPuram

6km

2

Bhavani puram To

Karakatta South

5km

3

Krakatta South to

Lanchi

revu/Punnami

Hotel

2km

1

Krishna Left Flood bank

(Bellow Prakasham

Barrage) From Brrage to Ramalaingeswara

Nagar (Krishna Lanka)

6.40km

Ranadheevi nagar

2

2

Taraka Ramanagar

1.40

3

Bhupesh Gupta Nagar

1

4

Ramalingeswar

Nagar

2

Budameru River/Drain

Information given in the following pages.

Floods

Floods are caused by two rivers in the Vijayawada. One is Krishna River which is on the southern part of the city and the other is Budameru River which is on the North- Western part of the city. Both these rivers contribute to the canal network. Bandar canal and Ryves canal are fed by Krishna River while Eluru canal is fed by Krishna River and partially by Budameru River. The contribution of water from Budameru is mostly seasonal and the canal networks are used to discharge excess/flood waters.

The topography of the city is complex. The central part of the city is above flood plain with hills while Southern and Northern parts of the city are on flood plain. This problem was realized by the irrigation department in later half of twentieth century and bunds were constructed along canals to prevent flood waters from entering the city.

The floods in Vijayawada city due to Krishna River, is a regular phenomenon. Almost every monsoon people living in the flood plains of Krishna River are affected.

Krishna Floods

The primary reason for the flooding is the unauthorized settlements along the river which had taken place due to lack of planning and enforcement.

Flood in the River Krishna are both due to South – West Monsoon in the middle of June and continues up to end of September and North – East Monsoon begins in October and continues till end of November. High floods usually occur during October.

History of Hazard

In general, flooding by the Krishna River is a regular phenomenon. The flood history of Krishna River indicates that its flow is uncertain. With the embankments in place the river flows bank to bank almost once in every five years or twice every decade. This time span of five years usually encourages low economic class people to settle on the flood bank. Further the presence of embankments provide a false sense of security to the people and also encourages people who are on the river bed that soon the government is going to construct a embankment that will protect their house. With the rapid increase in population, large numbers of people end up occupying the area between the flood bank along the Bandar canal and the Krishna River. These areas are subjected to regular flooding during monsoons. In order to safe guard the people and the livelihood the Irrigation department constructed a flood bank parallel to the old bund including the unauthorized settlements which had come up. This structure was designed to prevent the settlements from flooding. The old flood bank was then converted to serve the purpose of transportation (currently NH5). The people who were earlier residing in flood plain were provided with legal ownership and the area was included within the city town planning scheme.

Year Wise observed Maximum Floods in Krishna River

Sl.No.

Date

Month

Year

Cusecs

U/S Side

D/S Side

Barrage

1.

7th

Oct

1903

10,60,830

(+)70.55

(+)69.55

23.50

2.

11th

Aug

1914

9,48,632

(+)68.20

(+)67.95

21.15

3.

2nd

Nov

1917

9,55,460

(+)68.10

(+)67.25

21.05

4.

24th

Sep

1949

9,24,736

(+)68.15

(+)66.00

21.10

5.

2nd

Oct

1964

9,87,852

(+)68.25

(+)65.30

23.20

6.

6th

Aug

1966

4,12,734

(+)57.95

(+)55.90

12.90

7.

30th

Sept

1974

5.97.800

(+)60.65

(+)58.40

15.60

8.

10th

July

1983

8,27,310

(+)64.05

(+)62.35

19.00

9.

24th

July

1989

6,86,910

(+)61.95

(+)55.0

16.90

10.

17th

Oct

1998

9,32,000

(+)65.45

(+)63.30

20.04

11.

21st

Sept

2005

7,40,232

(+)62.65

(+)60.00

17.60

12.

17th

Aug

2006

5,56,618

(+)59.85

(+)57.60

14.80

13.

21st

Sept

2007

5,56,618

(+)59.85

(+)57.60

14.80

14.

11th

Aug

2008

4,22,660

(+)57.55

(+)55.20

12.50

15.

5th

Oct

2009

10,94,422

(+)68.78

(+)67.50

23.47

Source: Irrigation Dept

The maximum flood discharge observed during the year 1903 is 10.60 lakh cusecs. After the construction of the Nagarjuna Sagar Dam in the upstream of the river, during the year 1998 Krishna River received a maximum flood discharge of 9.32 lakh cusec and caused alarming situation throughout the flood banks below the Prakasam Barrage. Subsequently the flood banks of Krishna River were restored to original standards during the year 1999 to 2000.These restorations did not include flood banks which are within and nearby Vijayawada city namely Krishna Left Flood Bank (upstream of Prakasam Barrage) and Krishnalanka Flood Bank (downstream of Prakasam Barrage).

Reasons for Krishna Flood

This region receives maximum rainfall both by southwest and retreating monsoons.

The primary reason for the flooding is the unauthorized settlements along the river which had taken place due to lack of planning and enforcement.

Vijayawada is located on the line which separates the delta-irrigated lands.

Flood bank below barrage is about 6.40 km which creates havoc in flood season from June to December.

High Water release at time from barrage with 4, 12,734 to 10, and 94,422 Cusecs of water released in various years.

Developmental activities like sluice connectivity to into the river is causing back water (3 sluices connected into river).

Bund cutting for public private developmental activities (ex: sluice, storm water drains) approach roads for bigger vehicles.

Allotting the residential areas officially in flood zone. Ex: Police colony.

Breach occurrence and damages occurred to the flood bank with slips and erosion.

With little authoritative power over the settlements along the flood banks, the irrigation department is unable to attend swiftly in vulnerable areas.

This situation is further complicated by the false hope provided by the politicians in their campaigns during elections that they would support these illegal settlements. In order to gain vote, some of them even promise to protect these people by assuring that once they are elected they would legalize their settlements and will also revisiting the existing embankments. This measure was taken in 1970’s when the location of embankments were changed to include people who are in the flood plains.

Elevation and location details of Flood affected areas

Elevation and location details of Flood affected areas

Area

Elevation

Longitude

Latitude

Krishna River

37 Ft.

Krishna Lanka

86 Ft.

16030’17.70″ N

80036’22.61″ E

Krishna Lanka

72-83 Ft.

16030’12.64″ N

80037’19.48″ E

P.N.Bus stand

85 Ft.

16030’30.54″ N

80036’59.67″ E

VMC

97 Ft.

16030’38.41″ N

80036’42.15″ E

Krishna Lanka Tardwra

62-73-74Ft.

16037’27. 80″N

80030’11.79″ E

Ranadhive Nagar

74-79 Ft.

16030’20.69″ N

80037’12.75″ E

Bus Stand back

69 Ft.

16030’22.00″ N

80037’00.54″ E

Bhupesh Gupta

Nagar

55-64 Ft.

16029’46.92″ N

80038’07.91″ E

Ramalingeswara

Nagar UGD

53 Ft.

16029’07.94″ N

80039’21.17″ E

Police Colony

59 Ft.

16029’08.01″ N

80039’24.18″ E

K.R.Market

81 Ft.

16030’48.62″ N

80036’49.36″ E

Indira Gandhi

Stadium

70 Ft.

16030’17.72″ N

80038’17.23″ E

RTC Colony

85 Ft.

16031’51.24″ N

80036’15.21″ E

Gannavaram

80 Ft.

16031’50.99″ N

80047’45.57″ E

Patamata girls High

School

69 Ft.

16029’43.39″ N

80040’05.38″ E

Krishna River at

Punnami

52 Ft.

16031’28.76″ N

80035’08.48″ E

Punnami Ghat

82 Ft.

16031’34.71″ N

80035’16.88″ E

Source: Irrigation Dept

List of vulnerable areas to the Krishna flood

Vulnerability

population

area

Area

Krishna Flood

15557

1.15

Lanchi Revu

15722

1.88

karakatta

Krishna Flood

15814

2.81

Police colony

14798

0.65

Bhupesh Gupta nagar

14608

0.5

Tarakaramanagar

14725

1.46

Randheer Nagar

15418

0.72

15320

1.92

Busstand

(back)Saibaba

temple

121962

11.09

Source: irrigation Dept

Budameru Floods

The Budameru River flows from the North Western part of the Krishna District. The river originates in the hills surrounding Mylavaram and flows into Kolleru Lake. In order to control the floods the river is dammed at Velagaleru village, Budameru diversion channel (BDC) is constructed from Velagaleru to join Krishna River upstream of Prakasam barrage.

Budameru River is mainly controlled at two areas before reaching Vijayawada city. The first is the regulator across the Budameru drain at Velagaleru village and at Vijayawada Thermal Power Station (VTPS) which is located on the western part of the city on the upstream of Prakasam barrage. The Budameru River apart from flowing along the western part of the city towards the VTPS also enters the city from the north leading into the Budameru canal which runs parallel to Eluru Canal.

The problem starts at the tail end of the monsoon, with the reservoir being almost full (but not to its full capacity) and the occurrence of severe rainfall. Since the mandate of the regulator management at Budameru is to fill the reservoir to its capacity and the uncertainty within the rainfall information the release from the regulator drain block, water flow from local catchment causes flooding usually in the northern part of the city

The uncertainty in the rainfall is a common phenomenon within the Krishna Basin. This is especially due to the depressions and cyclones which form in both the Arabian Sea and Bay of Bengal. This uncertainty combined with the limited carrying capacity of the river and the proximity of the Velagaleru Village regulator provides low respite time for both the administrative personnel to prevent the floods and people to prevent their losses. The design and establishment of the EWS should take into account of this important aspect.

The Budameru flood assessment is based on the study of topography and location information collected from secondary sources. There was not much information made available with respect to the regulator release at the Velagaleru Village.

Budameru canal has already been indiscriminately blocked by developments and encroachments resulting in thousands of people abandoning their shelters to safe places, loss of property, leaving unhygienic environment for weeks.

Settlement along the river course, the vast land pockets on both the sides of the rivulet in New Rajarajeswari Peta, and the Rajeev Nagar area are the prominent low lying areas prove to flood disaster.

History

Budameru Water discharge during floods

Quantified Budameru Water discharge during floods

Sl.

No.

Date & Year

Discharge Through

Total

Discharge

in cusecs

Budameru in cusecs

Diversion

Channel in

Cusecs

Budameru

Course

Cusecs

(below

reguletor)

1

9.9.62

5900

2923

8823

2

22.8.63

6150

6168

12318

3

22.9.64

11125

28470

39595

4

19.5.69

7500

18580

26080

5

21.8.71

526

3196

3722

6

10.8.76

2225

14784

17009

7

31.7.78

6150

16302

22452

8

6.10.83

4250

9600

13850

9

13.8.86

6800

13200

20000

10

23.7.89

10625

24371

34996

11

11.5.90

7800

24473

32273

12

23.9.91

7500

18572

26072

13

24.8.2000

7850

3699

11549

14

20.9.2005

10945

14000

24945

15

20.9.2005

9900

7100

17000

Source: Irrigation Dept

Rainfall and Flood particulars

Rainfall and Flood particulars

Flood flow (Cusecs)

Year

Rainfall (MM)

Flood flow (Cusecs)

Actual

Normal

1988-89

1264

1029

24371

1989-90

1580

1029

24473

1990-91

921

1029

18572

2005-06

1239

1034

14000

2008-09

1188

1034

7100

Reasons for Budameru Floods

Flood plain

While Krishna River flooding affects to the flood plains on the outside of the embankments, but the Budameru River affects the entire North and North western part of the city. This is mainly due to the limited carrying capacity of the Budameru river channel and lack of sufficient mechanisms to drain the excess water during severe rain into the Krishna River.

The problem arises when Budameru catchment gets more than average rainfall within 24 – 48 hours. This leads to the reservoir in the Velagaleru village reach critical level forcing the irrigation department to release water causing floods in Vijayawada.

Adding rain water from local catchment and Hills.

2. The settlements

The population growth of the city has led to the slow movement of people towards the foot of the hills, which later led to expansion in to the flood zones. Even though much of these settlements are unauthorized the municipality attempts to cater to the basic needs of these illegal settlements by providing services such as roads, water supply and sanitation. These privileges have further encouraged the settlements in expanding in the high slope / risk prone areas.

Other reasons

Non feasible house constructions

Silting of drains

Back water due to conjution in storm water (HB colony, Bhavnipuram)

Raising the road levels in flood path

Occupying the flood bunds

Cutting the bund for development activities like bus shelters, beautification etc (Singh Nagar)

Less awareness about the situation and negligence about the problem among people.

Besides this chocking storm rain water canals, sluice and back water also cause the Budameru flood severely and damage the lives and property

Elevation details of probable Flood affected areas with Budameru

Area

Elevation

Longitude

Latitude

Ajit Singh Nagar

75 Ft.

16032’21.66″ N

80038’28.52″

E

Vambay Colony

68 Ft.

16032’14.17″ N

80039’17.80″

E

R.R.Pet

72 Ft.

16031’59.80″ N

80037’47.60″

E

Budameru at New

R.R.Pet

67 Ft.

16032’07.69″ N

80037’53.65″

E

Rajeev Nagar

67 Ft.

16032’15.18″ N

80039’12.40″

E

R.R.Peta field

67 Ft.

16032’43.98″ N

80037’25.68″

E

Jakkampudi

91 Ft.

16035’01.71″ N

80036’55.58″

E

LBS Nagar

68 Ft.

16032’59.87″ N

80036’55.58″

E

Andhra Patrika

Colony

16033’00.92″ N

80038’41.56″

E

Rajeev Nagar

64 Ft.

16033’22.73″ N

80038’45.93″

E

LBS Nagar

68 Ft.

16032’57.55″ N

80038’58.98″

E

List of Budameru flood effected areas

Budameru effecting Areas

S. No.

population

Area(Sq

km)

Circle

Division

Areas

1

7744.5

0.64

I

29

Rotary nagar, Ekalayvya nagar,Urmila subbarao nagar,ambedkar road,Kabela

2

7396.5

0.49

30

KLRao Nagar

7814.5

0.21

31

Deenadayal

Nagar,Ambedkar nagar

4

7861

0.94

27

Ambedkar Road

5

15201

1.25

28

Housingboard colony, Labor colony

Subtotal

46017.5

3.53

6

10

15

15355

0.33

2

36

Deenadayal

Nagar,Ambedkar nagar

16

13023

0.56

49

Old RR Peta

17

14092

4.21

52