Seepage in Existing Earthen Dams in Sri Lanka

In Sri Lanka, most of the irrigation reservoirs were constructed by ancient Kings and these were made using earthen dams. The main purpose of constructing these reservoirs was to supply water to the irrigation fields. It can be noted that most of the earthen dams are situated in the dry zone, especially North central, North and East of Sri Lanka. Even though, Sri Lanka has a very popular history of construction of earthen dams, condition assessments of earthen dams were not been properly addressed as Sri Lanka was conquered and controlled by Europeans for about 400 years, as well as 30 years of civil war in the North and East. Hence, at present, most of the existing earthen dams show signs of seepage and piping. In the global scenario, seepage of earthen dams is considered as the second driven factor which makes dams fail. As such, many research studies have been conducted to study the behaviour of earthen dams and their associated failures and mitigation methods, etc. However, in Sri Lanka, only very limited research studies have been conducted to study the seepage behaviour of earthen dams. Therefore, in this research study, the existing seepage conditions of some of the earthen dams in Sri Lanka were evaluated. Based on this research study, it was revealed that, at present, there is huge seepage in Tissa Wewa and Minneriya reservoir, which indicates the importance of utilization of proper seepage controlling techniques in Sri Lanka.