Assessment of Urban Sprawl and Its Impacts on Rural Landmasses of Colombo District: A Study Based on Remote Sensing and GIS Techniques

Abstract

Urban sprawl is one of the significant issues faced by cities in Sri Lanka today. Urban sprawl is unplanned and uneven pattern of growth, driven by a multitude of processes and leading to inefficient resource utilisation. This study evaluates urban sprawl and its impact on rural land masses of Colombo district, Sri Lanka in 1997, 2009 and 2018 using Shannon’s entropy values. Maximum likelihood supervised classification was applied for Landsat 8 OLI/TIRS (Operational Land Imager/Thermal Infrared Sensor 2018) and Landsat 5 TM (Thematic Mapper 1997, 2009) satellite images to get the build- up areas and then the Shannon’s entropy values using GIS were assessed. Calculated built-up areas were 98.97 (14.6 %), 178.76 (26.38%), 276.80 (40.85%) km² and Shannon’s entropy values were 0.928, 1.009 and 1.059 for the years 1997, 2009 and 2018, respectively. Since Shannon’s entropy is an efficient indicator to measure urban sprawl, it is observed that Colombo district continues to sprawl from 1997 to 2018. The analysis of the results further showed that rapid increase of built-up area resulted in decrease in vegetation and agricultural areas. Calculated relative entropy values were 0.83, 0.91 and 0.95 for consecutive years, which has an increasing trend and exceeded the threshold value of 0.5 indicating a higher level of urban sprawl in Colombo district. Developed maps show that since 1997, the city has experienced pronounced urban sprawl along the main roads of Colombo district consuming rural lands at a faster pace as population shifts from urban areas. Prioritised policies in Government’s public investment programme 2017–2020 for sustainable urban development may help concentrate growth within targeted areas and restrain sprawling development in rural settings of Colombo district. Further, similar studies are encouraged to check the effectiveness of applying policies.

Keywords

Urban sprawl Shannon’s entropy Landsat GIS supervised classification rural mass Colombo district

Get full access to this article

View all access options for this article.

References

Amarawickrama

Singhapathirana

Rajapaksha

(2015). Defining urban sprawl in the Sri Lankan context: With special reference to the Colombo metropolitan region. Journal of Asian and African studies , 50(5), 590–614.

Asif

Rahman

(2013). Land use and socio-economic responses to urban encroachment on agricultural land—a study of an Indian urban-rural fringe. Geograficky Casopis/Geogr J , 65(4), 289–314.

Bhatta

(2010). Causes and consequences of urban growth and sprawl. In Analysis of urban growth and sprawl from remote sensing data (pp. 17–36). Springer.

Bhatta

Saraswati

Bandyopadhyay

(2010). Urban sprawl measurement from remote sensing data. Applied Geography , 30(4), 731–740. https://www.sciencedirect.com/science/article/abs/pii/S0143622810000226?via%3Dihub

Chong

C. H. S.

(2017). Comparison of spatial data types for urban sprawl analysis using Shannon’s entropy (Doctoral dissertation). University of Southern California.

Colombo page. (2018). President opens housing complex for middle-income public, private sector employees. http://www.colombopage.com/archive_18B/Sep13_1536789775CH.php (accessed on 23 November 2018).

Deal

Schunk

(2004). Spatial dynamic modeling and urban land use transformation: A simulation approach to assessing the costs of urban sprawl. Ecological Economics , 51(1–2), 79–95.

Department of census and statistics. (2001). Census of population and housing. http://www.statistics.gov.lk/page.asp?page=Population%20and%20 (accessed on 22 October 2018).

Department of census and statistics. (2015). Census of population and housing. http://www.statistics.gov.lk/page.asp?page=Population%20and%20 (accessed on 22 October 2018).

10.

Department of National Planning. (2017). Public investment program. http://www.mnpea.gov.lk/web/images/PIP_English/EnglishPIP-1-8.pdf (accessed on 20 October 2018).

11.

Ding

(2009). Policy and planning challenges to promote efficient urban spatial development during the emerging rapid transformation in China. Sustainability , 1(3), 384–408.

12.

Geological Survey. Landsat-5, 8 image courtesy of the U.S . Geological Survey.

13.

Huang

X.X.

Sellers

J.M.

(2007). A global comparative analysis of urban form: Applying spatial metrics and remote sensing. Landscape and urban planning , 82(4), 184–197.

14.

Jagoda

(2009). Sustainable housing development for urban poor in Sri Lanka: Recommendations for the improving relocation housing projects in Colombo. http://www.lth.se/fileadmin/hdm/alumni/papers/ad2000/ad2000-14.pdf (accessed on 13 February 2018)

15.

Ministry of Mahaweli Development & Environment. (2016). Performance report. https://www.parliament.lk/uploads/documents/paperspresented/performance-report-forest-department-2016.pdf (accessed on 3 January 2018).

16.

Peerzado

M. B.

Magsi

Sheikh

M .J.

(2019). Land use conflicts and urban sprawl: Conversion of agriculture lands into urbanization in Hyderabad, Pakistan. Journal of the Saudi Society of Agricultural Sciences , 18(4), 423–428.

17.

Shahraki

S.Z.

Sauri

Serra

Modugno

Seifolddini

Pourahmad

(2011). Urban sprawl pattern and land-use change detection in Yazd, Iran. Habitat International , 35(4). 521–528.

18.

Satkunarajah

(1996). The effects of urban sprawl on agricultural land use in Sri Lanka: A case study on Gampaha District: A thesis submitted in partial fulfillment of the requirements for the degree of Masters in Philosophy (Agricultural Economics) (Doctoral dissertation). Massey University

19.

Sudhira

H. S.

Ramachandra

T. V.

(2007, July). Characterizing urban sprawl from remote sensing data and using landscape metrics . In 10th International Conference on Computers in Urban Planning and Urban Management, PR Brazil.

20.

Torrens

P. M.

Alberti

(2000). Measuring sprawl (CASA working papers 27). Centre for Advanced Spatial Analysis (UCL).

21.

Urban Development Authority. (2018). Middle income housing program. http://www.uda.gov.lk/middle-income-housing.html (accessed on 23 November 2018).

22.

Western Region Megapolis Planning Project. (2017). The Megapolis. https://www.megapolismin.gov.lk/web/index.php?option=com_content&view=article&id=60&Itemid=226&lang=en#master-plan (accessed on 12 November 2018).

23.

Zhao

(2010). Sustainable urban expansion and transportation in a growing megacity: Consequences of urban sprawl for mobility on the urban fringe of Beijing. Habitat International , 34(2), 236–243.

24.

Zheng

Myint

S.W.

Thenkabail

P.S.

Aggarwal

R.M.

(2015). A support vector machine to identify irrigated crop types using time-series Landsat NDVI data. International Journal of Applied Earth Observation and Geoinformation , 34, 103–112.