Cascading systems fed by the an ancient Yodha Ela Canal in Anuradhapura

Abstract

The settlements existed before the creation of irrigation works, fulfilled their requirements of water through natural resources which were arranged according to the natural landscape settings. Anuradhapura old Yodha Ela coming under this study and well before its creation, the settlements spread in the Kala Oya Valley upper lands, fulfilled their water requirements through cascade systems right from the early historical period. According to the sloping of the terrain from the uppermost lands up to the lowermost lands, the cascade is a system made up of a network of village tanks. The problem of this research study is to establish as to why Yodha Ela was constructed later on through this zone although the Kala Oya valley uppermost lands received water from the cascade. The objective of the research study, is to examine the cascade which existed before the construction of the Yodha Ela, and the environmental and physiological factors that caused their structural changes. In order to justify the research objective, and during the data collection, GPS, study of aerial photographs, drawing up of plans, earth coring methods, and during data analysis the use of GIS, examination of soil profiles, calculation of the mean sea levels, and the like research methodologies were followed. As the result of this research, establishment of the spread of the village tanks in this zonal area before construction of the Yodha Ela, physical grouping of the cascade, establishment of the topographical landscape pattern of the cascade system, to build up the case that Yodha Ela is a facilitating component of the cascade systems, and the establishment of the functionality of the Yodha Ela and the cascade, was done. Even though in the previous researches, the originating water resources of the cascade system was done, their functionality, and classification of topographical patterns have not been done. But the manner in which the activities of the cascade changed with the early historic irrigation works have not been covered those previous studies. In this research, the structural pattern of cascade as an early water management methodology of the zonal area through which the Yodha Ela flowed and an understanding of the topographical landscape pattern accordingly, variations in the climatic factors, population density, agricultural works, and changes due to the variations in those factors, through the cascade and as a facilitating component the construction of the Yodha Ela during the early historic period, and parallel to those water management methodologies, migration of settlements from the uppermost to the lowermost zonal areas, which factors were established in this research study.