Locating H-Based Potential Alternatives for Micro-Hydropower Development using Medium-Scale DEM Data and GIS.

Abstract

The knickpoint or anomaly steepness of a stream segment is the most important characteristic to be the potential H-based location either for micro-hydropower plant or weir site and gateway for irrigation canal. This study aims at locating anomaly-steepness segments of major streams using abrupt-slope change technique and normalized stream steepness indexing through medium-scale (1:50,000) DEM data of the Nam Khek watershed. The first technique compares slope of every pair of consecutive segments. The indexing applies the slope-area relationship expressed in terms of steepness (ks) and concavity indexes (θ) of each segment. Segments were identified as anomaly when their changes and indexes were higher than the thresholds. Through slope change and indexing analyses, 30 and 39 anomaly segments, H-based potential alternatives, were respectively identified out of total 177 segments. These anomaly segments were compared to proposed sites investigated by National Energy Administration (NEA, 1988) and well-known waterfalls in the area. A number of anomaly segments screened from the proposed methods help saving great budget and time consume for further field investigation.