O Photonirvaehak Journal of the Indian Society of Remote Sensing, Vol. 25, No. 3, 1997

Temporal Studies of Land Use/Land Cover in Varaha River Basin, Andhra Pradesh, India

K S R MURTHY and V VENKATESWARA RAO Centre for Remote Sensing, Department of Geo-Engineering, Andhra University, Visakhapatnam - 530003

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Introduction

Land is non-renewable resource and hence assessment of land use/land cover in temporal sequence is essential for planning and development of land and water resources. The remote sensing techniques provides excellent information about spatial distribution of land use/land cover in less time and cost effective manner. Air photo interpretation techniques have been used for mapping and monitoring of rural and urban land use for management and planning purposes (Gautam, 1978). Raghavaswamy (1982) highlighted the role of satellite remote sensing m land use planning in Kumang river

(Recd. 8 July '95; in final form 6 Nov. '97)

basin, Arunachal Pradesh. Satellite imageries have been widely used to study the land use and its capability by Srivastva and Narayan (1974), Prudhvi Raju and Vaidyanathan (1980), Nageswara Rao and Vaidyanathan (1981), Gautam and Narayan (1983), Reddy e t al.

(1990), Krishna Murthy e t al. (1992), Khan e t al.

(1994). In this paper results of temporal, study of land use/land cover in Varaha river basin in Andhra Pradesh are reported.

Study Area

Study area is a part of Visakhapatnam district of Andhra Pradesh. The area lies between

146 K.S.R. Murthy and

17~ 17055 '' latitude and 82~176 longitudes and covers an area of about 1132.70 sq. km (Fig. 1). The basin is situated in the eastern ghat mountain belt, representing dissected hill topography with undulating hills and deep cut valleys. The maximum elevation in the basin is 1164 m and the minimum 52 m. The climate of the area is semi-arid type with temperature varying from 15 to 20 ~ in winter and 32 to 38.8 ~ in summer. The average annual rainfall is about 1230.70 mm. The soils in the study area are classified as Ustipsamments, Quartzipsamments, Ustorthents Ustochrepts, and Haplustox. The important rock types exposed in the study area are khondalites, charnockites, calc-granulites and cpx-granites. Paddy and sugarcane are the important crops cultivated in major part of study area.

Data Used and Methodology

False colour composites of Landsat TM acquired in April 1986 and IRS IA (LISS II) acquired in May 1992 on 1:50,000 scale were

V. Venkateswara Rao

visually interpreted to map the changes in land use/land cover pattern as their spatial resolutions are most suitable for vegetation and water resources studies. Survey of India toposheets on 1:50,000 scale are also used as reference data. The image characteristics viz. size, shape, shadow, tone/colour, texture, pattern and various associated features were considered for the interpretation. The land use/land cover studies were carried out for smaller units after dividing the basin into 20 sub-basins. Inter basin and coastal basin area was also considered in the study. Maps depicting various land use/land cover have been generated using ground truth data and the details of the area have been presented in tabular form (Table 1).

Results and Discussion

The various land use/land cover classes delineated in the study area separately with Landsat TM imagery of 1986 and IRS imagery of 1992 are shown in Figs. 2 and 3 respectively.

Table 1. Total areal extent and percentage of different land use/land cover categories in VaraJaa river basin.

Classes Areal Extent (Km 2) Change

1986 Percent 1992 Percent Percent

Built-up land 21.25 1.88 36.95 3.26 1.38 Irrigated land (including 'podu') 372.08 32.85 381.71 33.71 0.86 Un-irrigated land 274.67 24.25 272.85 24. I 0 -0.15 Plantation 57.70 5.10 39.63 3.5 -1.69 Deciduous forest 1.52 0.13 4.70 0.41 0.28 Scrub/degraded forest 89.90 7.94 107.55 9.50 1.56 Forest plantation 6.00 0.53 2.00 0.18 -0.35 Gullied land 44.75 3.95 44.35 3.91 -0.04 Upland with/without scrub 245.17 21.65 232.42 20.53 - 1.11 Salt affected land 1.00 0.08 - - -0.09 Marshy land 7.18 0.63 2.62 0.23 -0.40 Sandy area 1.00 0.09 1.00 0.09 0.00 Rivers/streams/tanks 10.45 0.92 6.50 0.57 -0.35

Total 1132.67 100.0 1132.28 100.0

Temporal Studies of Land Use/Land Cover in Varaha River Basin... 147

�9 I I I I

I N D I A y ] ,o; ~;+o.. [ - ~

r'"\~++~~ :+!++'+. '+ ~ ++ -"i

A N D H R A PRADESH

13"lo' l 2"10'

VISAKHAPATNA M DISTRICT

12.2 0 12.l Kin-

II1" 0'

INTAPALLI

DADERU

CHOOAVARJ

II 2"Lo'

AHAKA PA L~

~SIPAT N A M f

~A.ANC H~

83 t [0 ~

flSA KHAPAT NA ~

Fig. 1. Location map of Varaha River Basin.

148

50'

III iii,

$2*~5'

K.S.R. Murthy and V. Venkateswara Rao

i i

bo: I-' I

I 2 " t SO'

S O U R C E : L A N D S A T TM 1 9 8 6 I ' " , ' I "~ 2 0 2 4Km.

50' ]

4 0 '

r ' 3s'" i

35'

, ~ SETTLEMENT W//.//~ IRRIGA TED ~ , ~

~ UNIRRIGATED 30' ~ PLANTATION

DECIDUOUS FOREST L \ ~ " ~ $CRUBIDEGRADEO FOREST i y Y~ FOREST PLANTATION

SALT AFFECTED LAND GULLIED / RAYINOUS LAND

MARSHY LAND UPLAND WI TN I WITHOUT SCRUB

IT" [ ,~j ~.1 SAttOV AREA 2S' ~ O RIV~RSII"ANKS

-- -- -- 5UBBASIN BOUNDARY ~. l , RAILWAY LINE

', 8, '13 S j t .o' 145 ~

17 ~ "i-/r

S 2 e I I I I I I I

Fig. 2. Land use/land cover map of Varaha River Basin - 1986.

"_.L $0'

Temporal Studies of Land Use/Land Cover in Varaha River Basin...

~ 2"T3s' ]~o' 14s"

so'

SOURCE:IRS 1A 1992 i I J | 2 O 2 & Kin.

149

/*S'

40 '

KOTAURAT

3 S '

m 30 t

17"

2S'

S E T T L E M E N T

~'/////~+ IRRIGA T ED /

U N I R R I G A T E O

P L A N T A T I O N

DECIOUOUS FOR Es:r L - ~ SCRUe/OEGRAOEO FOREST [VV V~l FOREST PLAHTA le lON

[ ; : ; 'J G U L L I E D I R A Y I H O U S L A N D

. | | | | I I~ MARSHY L A N D

[+ ] UPLAND W I T H / W I T H O U T SCRUB

SANDY A R E A ,L

+ + ~ D R I Y E R S I T A N K S -- - - - - S U B B A S I N B O U N D A R Y

' ' ' RA ILWAY L I N E

,,'1,," 1,o' .1,,' I

Fig. 3. Land use/land cover map of Varaha River Basin - 1992.

150 K.S.R. Murthy and V. Venkateswara Rao

Built-up land

The built-up land was found varying in shape and size from 0.5 to 3.35 sq. km in 1986 and from 0.5 to 6.5 sq. km in 1992 (Table 1). Nearly, 15.70 sq. km or about 73.9 percent of increment in built-up land was observed from 1986 to 1992. The increase in total area of rural settlements in built-up category is attributed to increase in population and house holds. There is almost three times increase in built-up land in sub-basin 11, where as in sub-basin 17 there is no change. The Narsipatnam and Etikoppaka are the major rural settlements in the study area, in addition to minor rural settlements. Agriculture being the major occupation of the region, is underdeveloped due to lack of proper irrigation system.

Irrigated land

The irrigated land feature with the largest areal extent (372.08 sq. km in 1986 and 381.71 sq. km in 1992) is identified as feature with light to medium red tone, fine/medium texture exhibiting scattered/contiguous pattern, varying in size, often rectangular in shape and mostly in association with built-up land and water bodies. The irrigated area has increased in basins 3, 4, 5, 13 and 16 by 9.63 percent from 1986 to 1992 showing the increase in groundwater resources utilisation during the period.

The major source of irrigation in the basins 13 and 19 besides groundwater sources is Komaravolu Ava and other streams. However, in both the basins the irrigated area reduced drastically from 50.87 to 40.00 in basin 13 and from 39.5 to 19.75 in basin 19 in a span of six years. The major cause of reduction in irrigated area is due to lack of water in the tanks and streams. The study reveals increase in irrigated area on the west side of the river because of the increased groundwater utilization as this area is mostly in the flood plain region with good

groundwater prospects. No significant changes in irrigated area are observed in the other basins.

In the basin, cropping pattern is categorised into irrigated and un-irrigated and varies with relief. At higher levels, jowar and maize are the main crops. In the lower parts of the valley jowar, maize, bajra and pulses are the important crops being cultivated under irrigated as well as rain fed conditions. Paddy is the major irrigated crop followed by rain fed sugarcane cultivated in low lying plains near Kotauratla during rainy season. Paddy field is confined to the river belt close to the streams where the soils are good and water is suitable for irrigation.

The groundwater source has not been exploited fully, as such tube wells, open wells and filter points are rarely found. In recent years coffee plantation in some areas have been started as a result of implementation of tribal development programmes. The plain land in the proximity to streams give better yields due to shallow groundwater table and fertile soil. On the moderate slopes of pediment (with thin veneer of debris) the plantations of teak, casuarina and eucalyptus are preferred. Around Narsipatnam, Rolugunta and some villages, vegetable crops like cauliflower, onions, tomato, brinjals, watermelons etc. are grown under tanks and small irrigation canals. The cultivation of crops along slopes and in marginal lands in the basin may lead to sheet and gully erosion rendering lands unsuitable for cultivation, thus these practices should be discouraged.

Un-irrigated land

In the un-irrigated land, crops like jowar and horse gram, black gram, red gram etc., are prominent during rabi season. In addition, coarse cereals like bajra, maize, ragi, and oil seeds like groundnut, ginger are grown during kharif season. Banana plantation is observed mainly near the coastal area.

Temporal Studies of Land Use/Land Cover in Varaha River Basin... 151

The areal extent of un-irrigated land in 1986 was 274.67 sq. km and in 1992 it decreased to 272.85 sq. km (Table 2). These figures show that there is no significant change in un-irrigated land from 1986 to 1992. However, there is considerable increase in un-irrigated land in sub- basins 2, 9, 11, 13, 19 and the coastal region while in other sub basins the area has decreased.

Deciduous forest

The light red tone with white patches and fine to medium texture with irregular shape and varying size identify, enabled to identify and demarcate deciduous forest from other features. It is identified in sub-basins 6, 10, 11 and 18. This category of forests comprise of species which shed their leaves during February-April. The total area of deciduous forests was only 1.52 sq. km in 1986 which increased to 4.70 sq. km in 1992.

Degraded forest

The False Colour Composite (FCC) shows the degraded forest in light grey to greenish white tone, fine to medium texture, irregular in shape and varying in size mostly associated with the forest, showing degradational characteristics. The type of forest has been identified in sub basins 1, 7, 8, 9, 10, 11, 12, 15, 17, 18 and 19 covering a total area of 89.90 sq. kms in 1986 which has increased to 107.50 sq. kms in 1992. The increase in area is attributed to the degradation of forest plantation due to human encroaches and failure of rainfall for a long time. The degradation of forests as observed in the Table ! is very high in sub basins 9, 10 and 19.

Salt affected and water logged marshy land

Salt affected land is identified near the mouth of Varaha river basin with an areal extent of one sq. km (in 1986) 'Kalupu' which is resistant to salt water is being grown by the local

people, and is used as firewood. Salt affected land of about one sq. km in 1986 is reclaimed in 1992.

Marshy land

Marshy land is the land which is permanently or periodically inundated by water and is characterised by vegetation which includes grasses and weeds. The satellite imagery manifests marshy land in dark grey tone, fine texture, contiguous pattern, varying size, irregular in shape and associated with water bodies especially in the confluent area of the river with the sea. The marshy land has been identified in sub basin 13 (1.125 sq. km) and near Varaha mouth.

Upland with or without scrub

The upland with or without scrub is one of the dominant land use/land cover category in the basin. It exhibits light pink to grey with pink mottling tone, with medium to coarse texture, scattered pattern, varying in shape and size and associated with hill tops far away from agricultural and built-up lands. Its location at higher altitudes renders it prone to degradation of top soil is washed down leaving the top more or less barren, with scanty scrub cover. Its areal extent decreased from 249 sq. km in 1986 to 245 sq. km in 1992. This unit is identified in almost all sub basins at different altitudes. Even though some of the uplands are used for 'podu' cultivation, the latter is not discernible in the imagery because of low spatial resolution.

Uplands with 3-6 slopes having thin soil cover, often support shrubs and grass. These areas can be brought under fodder and plantations through suitable soil conservation measures. Eucalyptus, Subabul, Casuarina and Sisam are the suitable species for such areas having moderate slopes.

Tab

le 2

. L

and

use/

Lan

d co

ver

clas

ses

and

thei

r ar

eal

exte

nt i

n 19

86 a

nd 1

992

in V

arah

a R

iver

Bas

in.

Sub

basin

Vo

.

1 2 3 4 5 6 7 8 9 10

11

12

. 13

14

15

16

17

18

19

2O

Inte

r ba

sin

Coa

s-

tal

Tota

l

Area

Bu

iltup

land

1986

19

92

16.8

0 0.

50

1.00

-34

.80

0.

50

1.30

-20

.30

1.

00

1.50

-20

.10

0.

50

1.25

53.3

0 0.

80

1.35

51.3

0 0.

50

1.15

45.5

0 1.

00

1.25

18.8

0 1.

00

1.30

60.3

5 1.

25

1.40

"

41.1

0 0.

50

0.60

-

38.8

0 0.

50

1.50

"

23

.80

1.

10

1.50

-

83.0

0 1.

00

1.55

"

30.8

5 1.

00

1.50

38.6

0 1.

00

1.75

51.5

5 1.

00

1.25

18.0

5 0.

75

0.75

12.3

0 0.

50

1.50

-

66.6

2 '

1.00

1

.00

-

10.5

0 0.

75

0.8

0-

254.

78

6.50

6

.50

-

141.

92

3.25

3

.25

-

1132

.7

21.2

36

.9

=

Irrig

ated

U

nirri

gate

d P

lant

atio

n D

ecid

uous

fore

st

Scr

ub de

grad

ed

Fom

st

fore

st

plan

tatio

n

m

- -

1986

19

92

1986

19

92

1986

19

92

1986

19

92

1986

19

92

1986

19

92

1.30

1.

50

2.00

8.25

8.

50

10.5

3.05

8.

05

9.25

7.10

13

.75

7.00

16.5

0 32

.10

23.5

"10.

75

4.75

18

.5

8.00

5.

375

12.5

4.00

3.

25

5.00

- 5.

20

14.7

2.50

4.

00

3.27

2.00

3.

00

1.00

53.8

7 40

.00

12.5

10.5

0 10

.25

2.00

8.25

17

.85

9.00

19,7

5 20

.75

6.00

0.50

2.

25

- 3.

40

39.5

0 19

.75

8.88

2.00

2.

20

110.

1 11

9.2

88.5

64.1

0 57

.53

40.4

372.

0 ,

381.

7 27

4.5

1.50

1.

50

13.0

0

5.00

1.

50

2.25

3.

25

15.0

0 8.

25

"10.

75

10.5

8.00

3.

25

2.50

-

17.0

0 8.

75

- 4.

20

6.00

15.2

5 3.

00

3.50

2.

50

6.50

8.

50

5.0

0

1.00

-

33.6

2 2.

50

78.5

3 i

48.4

5

272.

8 57

.7

4.00

2.50

15.0

0

5.38

-

4.25

-

0.75

1.

00

0.52

1.50

6.25

39.6

5 1.

52

- 1

.50

1.00

-

1.75

0.55

2.35

0.75

6.

00

1.00

17

.5

- 12

.7

- 3.

00

2.55

1.95

6

.32

-

2.3

7-

i 3

.25

-

19.5

-

10

.5-

14.7

89

.9

0.50

-

0.50

-

1.50

1.

00

-

2.25

1.

50

-

1.25

-

.50

6.50

0.

50

-

13.5

0 0.

50

.00

14.0

5

17.0

0

11.5

8

1.00

1.

50

0.50

" -

5.50

-

-

2.37

-

-

3.00

17.2

5

8.75

10.7

5 -

-

116.

25

6.00

2.

0E

Gul

lied l

and

986

~92

.75

.75

?.00

).00

~.15

5.00

~.75

3.00

10.~

0.1;

44.

Upl

and w

ith o

r w

ithou

t scr

ub

986

1992

I0.0

6.

75

- 15

.5

12.0

.00

1.25

.85

-

- 3.

25

- 9.

50

- 19

.0

'..25

5.

75

1.25

23

.7

.50

22.2

!.00

14.5

- 7.

00

i.O0

6.50

3.00

4.

75

3.00

4.

25

I0.0

14

.5

- 14

.2

- 5.

47

1.50

9.

7E

- 4.

5[

- 30

.;

- 19

.1

44.:

254.

S~

aff~

986l

2.75

.0

0

1.00

-

2.35

I

-

17.2

-

22.7

-

-

8.25

-

-

15.7

-

-

25.0

-

-

10.2

-

-

2.30

-

-

7.0C

-

-

8.1[

-

-

3.2 r

-

_

14.r,

-

_

7.5!

-

-

3.0;

-

-

10.~

-

-

4.5(

-

-

26.;

- -

232.

0 1.

00

-

Ma,

~y

I~

!

92

386

1992

1.12

1.

12

3.5

-

2.5E

1.

51

7.1;

2.

6:

OI

P

1986

19

92

1.5C

1.

0(

1.5[

1.

01

Riv

~/

St

r~

~s

and;

1k

s

1986

99

2

1.00

-

- 1.

00

0.85

-

1.10

-

2.50

-

3.00

3.

50

2.00

2.

00

i

10.4

6.

50

Temporal Studies of Land Use/Land Cover in Varaha River Basin... 153

Water Bodies

A number o f tanks are observed in the study area on the rolling plain. The tanks are small in size constructed by earthen materials across streamlets on the down slopes o f the undulating plain. The water in the tank~ is stored only during rainy seasons and rest o f the season they are dry. In summer and winter seasons, a few vegetable crops and jowar are cultivated in the drier parts o f the tanks because o f the availability o f moisture where fine sediments get settled. Komaravolu ava, about 10 km north o f Narsipatnam is being converted into a reservoir, across Varaha river, which received water from upper reaches through the Varaha river. Besides this, there are a number o f canals in the study area. No significant change is observed in other identified land use/land cover features.

The total areal extent o f each category o f land use/land cover is given in Table 1.

The sub basin wise areal extent o f each category of land use/land cover in 1986 and 1992 in the Varaha river basin is given Table 2.

Conclusion

The anthrapogenic activity has a major influence in the land use/land cover features of VRB as irrigated, un irrigated and rural settlements constitute nearly 60% of the total basin area. Moreover, increase in the total percentage of these land use categories from 1986 to 1992 also indicates enhanced human activity especially involving increased utilisation of water resources. This is evident as there is an increase of nearly 10 sq. km in irrigated land from 1986 to 1992. Increased rural settlements also undoubtedly involve increased tax on the water budget o f the area for domestic as well as agricultural purposes. Simultaneously consum- ption of rain water by agriculture seems to have reduced as indicated by the decrease in unirrigated area by 2 sq. km. The increase in

unirrigated area in sub basins 2, 9, 13, 19 is found to occur simultaneously with decreasing plantation probably indicating conversion of the later into the former, even though their quantitative changes do not occur. It is interesting to note a decrease in the area o f upland with or without scrub with an increase in the area of irrigated land and vice-versa, as seen in the basins 1, 2, 9, 12 and 17 respectively. When both these features show decrease in area from 1986 to 1992 an increase in unirrigated land has been recorded. The above change in possible probably because the areas with plantation and upland with or without scrub could be converted into agricultural land where irrigation is possible.

Acknowledgements

First author is grateful to Chairman ISRO, Bangalore, for granting fellowship under RESPOND project.

References

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Gautam N C and Narayan L R A (1983). "Landsat MSS data for Land use/land cover inventory and mapping: A case study of Andhra Pradesh", J. Indian Soc. Remote Sensing, 11(3):15-28.

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Khan M Q I, Rao D P, Venkataratnam L and Rao B R M (1994). Land evaluation for Micro-Watershed development by remote sensing. Proc. Int. Symp. Remote Sensing and GIS for Environmental Planning,

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Reddy R S, Thayalan S, Shiva Prasad C R, Reddy P S A and Sehgal J L (1990). Utility of satellite data for land evaluation in land use planning for a part of Northern Karnataka. J. Indian Soc. Remote Sensing, 18(4):34-44.

Srivastava R N, Narayana L R A (1974). An attempt towards mapping of land use of Dehra Dun city using aerial photo interpretation techniques. J. Indian Soc. Remote Sensing, 2(1): 19-27.