Mapping Colonial Irrigation Networks and Agrarian Transformation in the Indus Basin: A Historical GIS Reconstruction, 1850–1947

Abstract

During the colonial period and has undergone a drastic change in the agricultural ecology of the Indus Basin and in the agricultural history of the region, which is one of the largest irrigation systems by canal in the world. However, no quantitative studies have yet been carried out using Historical Geographic Information Systems (GIS) to explore the spatial evolution of these irrigation networks in the long term and its relationship to agricultural change. These were the objectives of the present study: attempt to reconstruct the spatial growth of colonial irrigation systems in the Indus Basin from 1850 to 1947, and analyze the relationship between the growth of irrigation systems and irrigated area, cropping intensity and agricultural output. A structured dataset of representative districts of the Indus Basin was created, which was used to build a Historical GIS. The following methods were used to analyse patterns of irrigation development and agrarian transformation: spatial visualization, descriptive statistics, Pearson correlation analysis and multiple linear regression. The results showed that the spatial development of the canals during the colonial period was uniform and that there was major increase in the area irrigated and the volume of the crops. The canal length, irrigated area and cropping intensity showed positive relationship with yield indices implying that irrigation infrastructure plays a central role in the agricultural development of the region under study. The HGIS methodology proved to be very successful for displaying the long-term spatial patterns, and also provided some quantitative information on landscape change as a result of irrigation. The study makes a valuable contribution to the Historical GIS field for having linked the geospatial reconstruction with statistical analysis, as well as to the knowledge of the colonial environmental history of the Indus Basin. Historical irrigation systems and agrarian change will be the focus of additional research in the future, building upon the analytical framework outlined here, which will be used in a practical way utilizing archival, GIS and remote sensing methods.