Practical Insights during Hydrological and sedimentological field works in Hydropower Projects

Abstract

Assessment of accurate hydrological and sedimentological data is very important for the technical and economic assessment of any water resource projects. Hydropower is not separate from this need. This article presents the experience gathered and lesson learned in field during hydrological and sedimentological investigations carried out from Project Development Department (PDD) of Nepal Electricity Authority (NEA) across seven hydropower projects in Nepal. The installed capacity of these seven hydropower ranges from small 0.6 MW to large 683 MW. The activates included river discharge measurements, installation and operation of manual staff gauges as well as Automatic Water Level Recorders (AWLRs), installation and operation of V-notch weirs, and suspended sediment sampling using USGS D-74 and handheld samplers. Site-specific challenges including boulder dominated rivers, diurnal flow fluctuations in snow-fed rivers, lake seepage quantification, and accessibility are documented along with adaptive remedial measures. Findings of this article highlight the necessity of continuous data recording through automated instruments, careful site selection, and periodic update of rating curve. This paper recommends adoption of site appropriate technologies, adherence to national and international guidelines to improve data quality.