Modelling topo‑bathymetric surface using a triangulation irregular network (TIN) of Tunga Dam in Nigeria

Abstract

Dams are built to store the water flowing from upstream to downstream. Sedimentation and siltation are some of the major problems affecting the storage capacity of dams. For effective management, bathymetric and topographic data are used to assess this challenge. In the Mambila Plateau of Taraba, Nigeria, the Tunga Dam is a multifunctional reservoir that serves as a small hydropower, irrigation and domestic use dam. Nonetheless, it is not operating to its full potential, leading to issues such as frequent stoppage of the turbine, low irrigation activities and a shortage of water supply for domestic use. To determine the basin’s approximate present volume, a topographic and bathymetric survey was conducted using a differential global positioning system (DGPS)-Hi-Target V30 and a single beam echosounder to acquire the real-time data. The data were processed, and the digital elevation model (DEM) of the study area was modelled using a triangulation irregular network algorithm (TIN). The deepest point of the dam was found to be 21.25 m, and the volumetric capacity was assessed based on the elevations. The tessellation data format adequately represents the reservoir DEM for future purposes to better enhance the reservoir capacity. Hence, the research suggested that dredging should be carried out to boost the basin’s capacity. Likewise, an embankment can be constructed around the dam to enhance the basin’s storage capacity. The dredged material can be used to achieve the barrier’s building, which will reduce the overall cost.