Processing of SLAM LiDAR Data for Surface Water Runoff Analysis at Pura Agung Wira Loka Natha

Abstract

Surface runoff has been observed inside the Pura Agung Wira Loka Natha temple complex, Cimahi, West Java, since the construction of a nearby underpass road, a condition that had not previously occurred. Preliminary evaluation using Copernicus GLO-30 DEM data failed to detect the suspected micro-scale elevation change responsible for this phenomenon. This study aims to process Simultaneous Localization and Mapping (SLAM) LiDAR point cloud data into a Digital Terrain Model (DTM) and to analyze the existing topographic conditions in order to identify the factors contributing to the surface runoff. Data were acquired using an RTK-integrated Hi-Target V700S SLAM LiDAR device, with ground control points established through static GNSS observation, and validated against independent Total Station measurements. The accuracy assessment yielded a combined three-dimensional RMSE of 0,0358 m. The Digital Terrain Model revealed an elevation difference exceeding 2 m between the road and the temple courtyard, confirmed through cross-sectional profiles showing consistent elevation drops along the boundary wall. Flow Direction and Flow Accumulation analysis, with a maximum accumulation value of 85,100 cells, demonstrated that the runoff network originates from the road and flows continuously into the temple complex. The predominantly flat topography of the temple courtyard (slope 0°-5°) further limits natural drainage, resulting in ponding potential across nearly the entire main courtyard. These findings confirm that the surface runoff is caused by a combination of the road-temple elevation disparity and the temple's inherently flat internal topography.