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

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

Residential ( Built -up )

1348.25

35.92

21.79

Mixed-Residential ( Built -up )

141.36

3.77

2.28

Residential vacant plots

229.02

6.10

4.11

Commercial

247.91

6.6

4.01

Industrial

72.38

1.93

1.17

Public & Semi- public

270.16

7.2

4.37

Institutional

178.31

4.75

2.88

Parks & Play grounds

60.34

1.60

0.56

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

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

Krishna Left flood bank

(above Prakasam Barrage)

13.00

Krishnalanka Flood bank

(below Prakasam Barrage)

6.40

Krishna Left flood Bank (below Prakasam

Barrage)

89.60

Divi Left flood bank

36.00

Divi Right Flood Bank

32.00

K.E. Tidal Bank Divi Island

22.00

Kona Tidal Bank (Machilipatnam Side)

18.50

Seadyke Flood Bank (Machilipatnam Side)

2.50

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

Krishna Left Flood Bank(Above Barrage) From ( Ibrhimpatnam

to Prakasham Barage)

13km

IbrahimPatnam to

BhavaniPuram

6km

Bhavani puram To

Karakatta South

5km

Krakatta South to

Lanchi

revu/Punnami

Hotel

2km

Krishna Left Flood bank

(Bellow Prakasham

Barrage) From Brrage to Ramalaingeswara

Nagar (Krishna Lanka)

6.40km

Ranadheevi nagar

Taraka Ramanagar

1.40

Bhupesh Gupta Nagar

Ramalingeswar

Nagar

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

7th

Oct

1903

10,60,830

(+)70.55

(+)69.55

23.50

11th

Aug

1914

9,48,632

(+)68.20

(+)67.95

21.15

2nd

Nov

1917

9,55,460

(+)68.10

(+)67.25

21.05

24th

Sep

1949

9,24,736

(+)68.15

(+)66.00

21.10

2nd

Oct

1964

9,87,852

(+)68.25

(+)65.30

23.20

6th

Aug

1966

4,12,734

(+)57.95

(+)55.90

12.90

30th

Sept

1974

5.97.800

(+)60.65

(+)58.40

15.60

10th

July

1983

8,27,310

(+)64.05

(+)62.35

19.00

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

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)

9.9.62

5900

2923

8823

22.8.63

6150

6168

12318

22.9.64

11125

28470

39595

19.5.69

7500

18580

26080

21.8.71

526

3196

3722

10.8.76

2225

14784

17009

31.7.78

6150

16302

22452

6.10.83

4250

9600

13850

13.8.86

6800

13200

20000

23.7.89

10625

24371

34996

11.5.90

7800

24473

32273

23.9.91

7500

18572

26072

24.8.2000

7850

3699

11549

20.9.2005

10945

14000

24945

20.9.2005

9900

7100

17000

Source: Irrigation Dept

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″

Vambay Colony

68 Ft.

16032’14.17″ N

80039’17.80″

R.R.Pet

72 Ft.

16031’59.80″ N

80037’47.60″

Budameru at New

R.R.Pet

67 Ft.

16032’07.69″ N

80037’53.65″

Rajeev Nagar

67 Ft.

16032’15.18″ N

80039’12.40″

R.R.Peta field

67 Ft.

16032’43.98″ N

80037’25.68″

Jakkampudi

91 Ft.

16035’01.71″ N

80036’55.58″

LBS Nagar

68 Ft.

16032’59.87″ N

80036’55.58″

Andhra Patrika

Colony

16033’00.92″ N

80038’41.56″

Rajeev Nagar

64 Ft.

16033’22.73″ N

80038’45.93″

LBS Nagar

68 Ft.

16032’57.55″ N

80038’58.98″

List of Budameru flood effected areas

Budameru effecting Areas

S. No.

population

Area(Sq

km)

Circle

Division

Areas

7744.5

0.64

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

7396.5

0.49

KLRao Nagar

7814.5

0.21

Deenadayal

Nagar,Ambedkar nagar

7861

0.94

Ambedkar Road

15201

1.25

Housingboard colony, Labor colony

Subtotal

46017.5

3.53

15355

0.33

Deenadayal

Nagar,Ambedkar nagar

13023

0.56

Old RR Peta

14092

4.21

New RR peta, Arunodya nagar, Tammina Durga Rao Nagar, Nandamuri Nagar

14641

0.65

Indira nayak Nagar, Kanakadurga Nagar, Andhra Patrika Colony

14723

1.56

RK Puram, Vijayadurga nagar,Devinagar

13671

0.68

Ayodhya nagar

13234

0.44

LBS Nagar,Patel nagar

13904

1.39

Old Rajeev Nagar, Vaddera Colny,VUDA colony,New Rajeev nagar

13490

2.71

Radha Nagar,Prajasakthi Nagar,Kandrika Bose Nagar(NSC

13927

0.35

Singh Nagar

13253

1.36

Vambey Colony

subtotal

153313

14.24

14029

5.93

Sangam Road, Gandhiji colony,Karmel Nagar, Joseph Nagar

subtotal

14029

5.93

Storm water drainage system

All these water channels contribute in draining the surface run off from the city and hence have been referred as the major drainage areas of the city.

In most part of the city, there are no separate systems to carry the sewage and storm water separately. Except for 390 km length of the roads, where UGD exists, the rest of the road side drains also serve as sewers round the year. In fact, save during the monsoon months spread over July-September, the rest of the year, the drains carry only the sewage. Also during the monsoons, the wastewater from the kitchen and toilets get diluted with the storm water. The main drainage system of the city is narrated in the following paragraphs.

Budameru Channel Drainage area

Budameru Channel is the major drainage channel of the drainage area and receives the surface runoff from the catchment area.

Krishna River East Drainage area

The drainage area covers the south-eastern part of the city. Most part of the core urban area, namely, Krishna Lanka, GovernorPet, Punnamma Thota, Kasturibai Pet, Moghalrajpuram and Badavpet lie in this drainage area. The river Krishna is the final recipient of the storm water runoff from this drainage area through a number of roadside drains. Bandar canal towards the east across the drainage area also carries a substantial quantity of storm runoff as well as sullage, sewage from the drainage area.

Ryves Canal Drainage area

The area under this drainage area is highly developed except for part of Gunadala hill. Gandhi Nagar, Durga Agraharam, Durgapuram, Chuttugunta, Maruti Nagar and Machavaram are major high density localities in this drainage area.

Krishna River West Drainage area

The drainage area comprises southwestern part of the city. The old town area as well as prime localities namely Mahatipuram, Wynchipet, Mallikarjuna Pet, Vidyadhrapuram and a number of housing colonies are located within the drainage area. The drainage area has a highly undulating topography with Indrakiladri hills located within it. The topography is sloping downwards from north to south. Almost the entire quantity of storm water runoff is led towards the river Krishna by a number of roadside drains. The present drain lengths are at an average ratio of 1.04 with the existing road lengths which is very less than the minimum standards. So keeping in view the topographical features of the city, new drains have been proposed with an average length ratio of 1.5 with the existing road lengths.

Existing Drain Length (both open and UGD): Vijayawada, 2003 Length in km

Circle

Road length in km

Roads with open drains on one side

Length of Roads with open drains on both sides

Total length of Roads with open darins

% of roads with drains

Open drain

UGD length in km

373.39

23.68

141.5

165.1855

44.24

306.69

210.81

23.58

140.86

164.434

305.29

170

III

656.52

39.42

235.52

274.9385

41.88

510.46

222

Total

1240.72

86.68

517.88 604.5605

48.73 1122.4

392 Issues

The existing UGD system covers only 21 % of VMC central zone area and other drainage systems cover 49%. Rest of the 30% of the city area lacks proper drainage system.

As of 2004, there are around 1120 km of drains in the entire city and 896 drain cleaners work for the operation and maintenance. This is said to be inadequate resulting in poor quality of maintenance of drains.

Long stretches of drain are kutcha.

Storm water drainage network is inefficient and inadequate in almost all the wards of the city

Few areas like Ajit Singh Nagar, Payakapuram and Prakash Nagar are prone to flooding during heavy rains because of Budamerru stream.

Flooding of roads by sewage occurs due to encroachment, silting and solid waste dumping on the drainage channels, which lead to the canals in the city.

Strategy for Development

To provide cost effective UGD system or closed drains to cover all areas of circle II and III to enhance the environmental quality and hygienic condition in the City.

Upgradation of existing kutcha drains to pucca drains

Provision of pucca drains in new developing areas of the city.

To have a close tie up with PWD for undertaking improvement programmes for providing Storm Water Drains including the desilting works of the canals in the city.

To clear encroachments along the drainage channel to facilitate smooth flow of storm water and to keep the area clean and to reduce the pollution along the canals. This will enhance the linkage between the reservoirs to store rainwater in the Town.

FLOOD RISK ASSESSMENT

Risk Assessment (Krishna River)

S.No

Hazard

Parameters

Genereal Assessment

Risk Assessment

Flood Risk Assessment

(Krisna Flood)

Annual Rainfall

Range of Annual Rainfall is 700-1000mm is creating flood in NE and SW Monsoons

Water catchment

Hugh water catchment area near about 13.68Sq km

Can be able to hold upto 7 lakh cusecs

Barrage capacity

Barrage water holding capacity 12lakhs cusecs

Can hold upto 12 lakh cusecs if exceeds dam failure may occur

Time to reach flood water from upper catchment

2 to 4 days depending on the rainfall

Local catchment, inflow of local streams also increase the flood intensity

Shape of River

Rectangular shape with straight flood bank

13 km and 6.40 km of flood banks, But height of the flood bank is being decreasing downwards.

Soil

Black cotton soil and alluvial soil which hold moisture for maximum time

Ground growth

Very less ground can be observed

Drainage

Even there is no UGD in many areas of flood zone, but storm water drains were built. Apart from these, three sluices were connected to release the drain water into the Krishna river.

These sluices will work reverse by taking back water

Elevation

43 m to 60 m height

Very near to flood bank height

Risk Assessment (Budameru)

S.No

Hazard

Parameters

General Assessment

Risk Assessment

Flood Risk Assessment

(Budameru flood)

Annual rainfall

Range of annual rainfall is 700-1000 mm is creating flood in NE and SW monsoons

Water catchment

Huge water catchment area near about 23.7 sq km

Huge area than Krishna flood area

Regulator capacity

Regulator at Velagaleru can hold 35000 cusecs of water

Highest area than Krishna flood area

Time to reach flood water from upper catchment

2 to few hours to one day depending on the rainfall

Shape of river

Irregular shape with no or less flood banks and less height( 1 feet to 1 meter only)

This is the one of major cause

Soil

Black cotton and red gravelly soil which holds moisture for less time

Water sinking nature is less

Ground growth

Other than in residential areas , thorny bushes, grass growth is more

Contaminated food

Food cooked in unhygienic conditions is making people ill with food poison, vomiting etc

Health facilities

Health centres are not having appropriate vaccines and drugs

10.

Sanitation

Poor sanitation in Krishna and Budameru flood zones are making people ill

SCENARIOS (CAUSATIVE FACTORS)

Causative factors

Possible risk

Extreme single day or two day rainfall in the Krishna catchment when the Nagarjuna Sagar reservoir is full. Such occurrence is possible due to cyclonic activities (including depression) in either Bay of Bengal or Arabian sea

Floods in southern part of the city including areas inside of the embankments, possible breach of embankments, lifeline services including water supply, sanitation and electricity may be damaged/affected

Extreme single day or two day rainfall in the Budameru catchment during the tail end of monsoon

Floods in north and north western pars of Vijayawada city

Extreme single day or two day rainfall in Vijayawada due to cyclones

Damages to buildings, floods within the city and possible overflow of canal followed by health risk

Mitigation Measures

Mitigation measures are very important phase of disaster management. They will help to reduce the loss and increase the capacity of people in managing the disasters.

Krishna floods

S.No.

Name of the activity

Estimate (Rs in

Lahks)

Agency

Work Status

As per the building byelaws 1981, no permission to construct a building on site shall be granted, if the site is within 9 meters of the highest water mark of a tank.

Further the authority may

require the floor of the lowest storey of such building to be raised above the normal minimum flood level of the adjoining to ground or to such other level as the authority may prescribe

Shift or restrict the people living in flood banks to safe place by providing all amenities

Shift to temporary centres when receiving the 1st warning

Krishna Bund strengthening at Krishnalanka, Anadheevinagar,

Bhupesh Gupta Nagar

SE, Irrigation

initiated the

work

Krishna bund construction

from Police Colony to Yanamala Kuduru

5000

work initiated

but stopped due

to communal

conflicts

Raising the free board of Krishna flood bunds from 1.5 metre to 2 meters

SE, Irrigation

have been

submitted for

K.L.F. Bank and

K.R.F. Banks

Shift the habitants of the flood zone of Budameru temporary or permanent shift the habitants of the flood zone of Budameru temporary or permanent

Commissioner, VMC

Stop occupying the Budameru bund from Singh Nagar to NSC Bose Nagar

Providing Road side rain water drains at Bandar road

5196

Commissioner

,VMC

initiated the work

Providing Road side rain water drains Ayyappanagar Road

1948

Commissioner

,VMC

yet to begin

Providing Underground drainage and sewer lines

and construction of sump

cum [Pump house]

232

Commissioner

,VMC

yet to begin

10.

Construction of Flood banks for Krishna River and Budameru Floods

10400

SE: Irrigation, Commissioner

,VMC

yet to begin

The proposals for raising the free board have been submitted for K.L.F. Bank and K.R.F. Banks.

SE,Irriataion

yet to begin

construction of electrical grave yard Ramalingeswar Nagar

120

Commissioner

VMC

yet to begin

construction of 10 shelters /Rehabliataion shelters at

Safe zones

300

Commissioner

VMC

yet to begin

Procuring rescue equipment at various locations

Commissioner

VMC

yet to begin

shifting and construction Housing f or the Krishna flood bank residents

52000

Commissioner

VMC

yet to begin

Renovation or construction of safe schools and providing safety equipment at schools

DYEO,VMC

yet to begin

procuring food for flood effected people

POUCD, VMC

yet to begin

Providing health camps and Medicine stock

CMHO VMC

yet to begin

Provision of Food to lactating mothers and Infants and children under 6 years

PDw&C

yet to begin

reconstruction of rubbish or spoiled roads in many points of the city to protect form water stagnation

R&B

Dy. SE.

yet to begin

20a

Filling and repairing the ditches and exposed road

yet to begin

Construction of 50 animal sheds at safe zones

Joint Director

Animal

Husbandry

yet to begin

Identify the high milk production and other animal or bird production areas, based on that preference should be given to provide all measures to those cattle and birds safety and multiplication

Joint Director

Animal

Husbandry

yet to begin

Total

23436

Budameru floods

S.No.

Name of the activity

Estimate (Rs in

Lahks)

Agency

work Status

As per the building byelaws 1981, no permission to construct a building on site shell be granted , if the site is within 9 meters of the highest water mark of a tank

Further the authority may require the floor of the lowest

storey of such building to be raised above the normal

minimum flood level of the adjoining to ground or to such

other level as the authority may prescribe

Construction of Storm water drain along inner ring road

between Pipula road to Kanakadurganagar main road

83.34

Chief Engineer

VMC

Initiated the work

shift to temporary centres when water level

Commissioner

VMC

Construction of Storm water drain along Railway track from RR Peta railway level crossing to Budameru Bridge.

134

Chief Engineer

VMC

Initiated the work

Construction of Storm water drain along Nuzvid road from

Pipula road to Rly.Track side church in Singhnagar.

196.78

Chief Engineer

VMC

yet to begin

Construction of Storm water drain along inner ring road

between Pipula road to Kanakadurganagar main road

356.57

Executive

Engineer 2 VMC

yet to begin

De-silting of all the kutcha drains and also for all along this temporary drains provided up to 33 vents in being taken up by VMC proposed to provide 800 / 900 / 1000mm dia available unused pipes of VMC can be used in 2 or 3 rows at important crossings with sufficient width for cart passage wherever necessary to facilitate the farmers field to stop the obstruction of water flow

Executive

Engineer, VGTM

UDA,

Annual maintanance

As per historical data, flood flow coming from upper catchment areas and actual run- off coming over the existing IRR, as sheet of water has to be assessed. The IRR will act as retaining wall which leads to inundation in the catchment area and resulting submergence of habited areas.

Executive

Engineer, R&B,

and Executive

Engineer,

Drainage, VMC

Strengthen the Budameru bund and protect it from Rodents, illegal ploughing for approach path, removal of bund mud for other purpose

20411

Raise the culverters on Budameru drain and maintain the road level always low.

Sc, Irrigataion

initiated

the work

desilting, de weeding of the Budameru drain

Protecting wall through habitations from Budameru drain

Commissioner

,VMC SI,Police,

SI, VMC

yet to

begin

Irregular shape of the Drain should make as strait line so that water drains fast and inundates slow and water get percolates into the soil.

Sc, Irrigation

yet to

begin

Provide manpower to monitor such encroachment or authority to bring down the structures which have encroached into the flood banks.

Sc, Irrigataion

Commissioner

,VMC

Commissioner,

VMC

AC(G), VMC

yet to

begin

Houses should construct above drain level.(2 meters high)

Commissioner

,VMC

CE/SC/EE,VMC

CP,VGTM,

EE,Housing

yet to

begin

CONCLUSION

The study area (Vijayawada city) is highly affected by the flood and it is necessary to identify the factors responsible and the impact flood has on Vijayawada. As a part of the study the regions which are affected by the previous floods have been mentioned, the effects of the Budameru canal and Krishna River on the city have been discussed. The risk assessment of the Budameru canal and the Krishna River has been done. Increase in the water levels of Krishna River and the Budameru canal are the main reasons for the flooding of the city. The local authorities and the government are working hard to make the city less prone to floods. The hazard risk of the region cannot be mitigated completely but the vulnerability of the region can be reduced by proper planning and implementation of disaster management.

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