Open technologies based tank management model for flood risk reduction

Abstract

Analysis of climate induced phenomenon is data intensive and the data collected from very sparse network of professional weather stations have become incapable to estimate the magnitude of the climate induced events. Manual stations, offline data, low spatial and temporal resolution of data, high cost of modelling software and state-owned stations’ data, unavailability of pre-determined parameter values, lack of trust on technology and lack of expertise knowledge, are the barriers exist in most developing countries, which evade inclusion of hydrological modelling approaches for tank / reservoir water release decisions. Presently, in Sri Lanka, the reservoir water is released once it reaches to a particular threshold. The public is informed few hours prior to the opening of reservoir gates. This current practicing way of releasing water from the reservoirs increases the potential for dam failures and public outrage, and thus strains reservoir operators to open the spill gates during emergency periods. Therefore, for a low-income country, a total open-source solution, combined with low-cost open-source hardware, free and open-source software and open standards was seen as the only possible way to overcome the flood risk associated with reservoirs. Thanks to the 4ONSE (4 times Open and Non-conventional technologies for Sensing the Environment) project, a dense open-source sensor network has been deployed in Deduru Oya watershed following a new deployment approach. Deduru Oya reservoir was chosen to develop the tank management model, as it is the main player of controlling the floods in the lower basin. The tank management decision support system presented in this research is supported by a hydrological model developed from SWAT open-source tool, fed with 4ONSE big data. Further, this research introduces a novel approach to find the dominant parameters and their values at any spatial and temporal scale. The calibration and validation results have revealed the potential of the open technologies-based tank management approach in controlling the reservoir floods.