Flood vulnerability level analysis as a hydrological disaster mitigation effort in Krueng Jreue Sub-Watershed, Aceh Besar, Indonesia

Abstract

The flood phenomenon in the Krueng Jreue Sub-Watershed, Aceh Besar, Indonesia, in recent years indicates biophysical damage to the land. Floods are influenced by factors from biophysical conditions of the land and high rainfall with small river cross-sectional capacity causing water to overflow the embankment and flood low areas. This research aims to analyse the flood vulnerability level in the Krueng Jreue Sub-Watershed, Aceh Besar, Indonesia. The results showed that flood vulnerability in the research area consisted of four classes: very vulnerable, vulnerable, moderately vulnerable and somewhat vulnerable, with each area averaging a score of 43.0, 38.8, 30.0 and 21.7. Types of land use that are particularly vulnerable to flooding are rice fields with a mean total score of 43.0. The vulnerable classes are found in settlements and moorings, with a total score of 42.0 and 36.5, respectively. While open land, shrubs, grasslands, primary forests and secondary forests are quite vulnerable to flooding, with a mean total score of 32.5 each: 30.0, 30.0, 28.0 and 27.0. The main components affecting flood vulnerability are rainfall, temperature and land use, while additional components are soil infiltration and slope. Mechanised hydrological disaster mitigation can be performed through optimisation of weir, embung, rorak and check-dam. Vegetative hydrological mitigation efforts can be performed by reforestation and agroforestry systems, maps and flood prediction. Non-technically, hydrological disaster mitigation efforts can be undertaken with legal policies, law enforcement, map creation and prediction of droughts and socialisation of legislation.

Fluvial and coastal landform changes in the Aceh River delta (northern Sumatra) during the century leading to the 2004 Indian Ocean tsunami

“…Irrigation schemes included the construction of reservoirs that trap the sediments delivered to the Aceh River. The Keuliling Reservoir (catchment area of: 38.2 km 2 , Azmeri et al, 2015; Helmi et al, 2019), completed in 2008 in the catchment of the Aceh River, undergoes high sedimentation rates (Yulianur et al, 2015). Four other reservoirs, constructed since the 1990s, likewise impede the delivery of sediment to the delta.…”

Farmers’ Disaster Mitigation Strategies in Indonesia

“…In the cities, flood is commonly caused by water that is not well absorbed due to reduced absorption surfaces. The main components affecting flood vulnerability are rainfall, temperature, and land use, while some additional factors include soil infiltration and slope [20]. Even if the water flow is large, if the absorption surface is available enough, the flood is less likely to occur.…”

“…Therefore, this paper aims to understand this issue, and then it can be used for developing disaster mitigation strategies at the farmers level and or all related parties. In addition, as the main elements of agriculture, when agriculture is one of the vulnerable sectors from disaster [20], farmers are vulnerable too. Most of the farmers live in rural areas.…”

Flood Quantification Index Based on Inundation Indicators and Risk Scale

“…Five parameters were used: accumulation of discharge, land use, slope, rainfall intensity, and elevation to detect floods' spatial distribution. Each of these parameters is given quantification weight so that there are five qualification levels, namely very low, low, medium, high, and very high [6]. The Flood Risk Index Map was developed to estimate flood hazards and vulnerabilities in the Bukit Duri sub-district, Tebet District, Jakarta, in the upper reaches of the Manggarai Watergate.…”