PCA driven watershed prioritization based on runoff modeling and drought severity assessment in parts of Koel river basin, Jharkhand (India)

Abstract

Global warming influencing regional climate is playing a significant role in triggering the recurrent drought. The current study demonstrates a PCA (Principal Component Analysis) driven watershed prioritization in a part of Koel river basin by runoff computation during monsoon season along with assessment of Vegetation Health Index (VHI) derived from MODIS satellite data during the period from 2000 to 2017. Koel river catchment area of 7,261 sq km was divided into 82 sub-watersheds based on drainage networks derived from Survey of India (SOI) topographical map on scale 1: 50,000. High resolution satellite image of Sentinel-2 was used to prepare land use land cover map. Soil conservation service curve number method (SCS CN) was used to estimate runoff. Result obtained from runoff estimation of 82 sub watersheds shows high runoff (50 to 60% of rainfall) with 290,000 m3 total runoff volume in the upper and middle parts of the catchment dominated by agricultural/fallow and barren lands whereas low runoff was estimated (20 to 30%) with 29,467 m3 in the lower catchments where a large area is covered with forests. The value of satellite based VHI ranges between 23 to 53 with major parts of the area exhibiting values less than 30 reflecting poor vegetation health. Most of the sub-watersheds in parts of Ranchi, Lohardaga, Gumla and Khunti districts experienced high total runoff with poor vegetation health index reflecting more proneness to drought. Watershed prioritization was done based on correlation among four parameters viz., rainfall, drought zones, direct runoff and total runoff through PCA. Strong correlation between total runoff volume and drought areas was used for watershed prioritization which indicated 42 sub-watersheds (4,703 sq km) in the upper catchment required high prioritization. The outcomes of study would help proper planning of water resources and soil moisture management to overcome the recurrent drought conditions at watershed level.

Assessing heavy metal and physiochemical pollution load of Danro River and its management using floating bed remediation

“…The study area includes a peri-urban area, having an elevation range from 226 to 608 m. Danro River Basin, which flows into the North Koel River which ultimately joins the Ganga River Basin is covered in undulating terrain with a modest slope. The basin receives high rainfall (1500 mm/year) and drains quickly 67 . Land use is diverse with forests (811.4 km 2 ) and agriculture (1617.5 km 2 + 1693 km 2 cultivable).…”

“…The climate is seasonal with a rainy season (Nov-Mar). Most of the basin is arid but the north is temperate and the south is tropical savannah 67 . The basin is economically important (agriculture, tourism, fishing, forestry, mining, transportation) but faces challenges like heavy metal pollution, decreased water table, soil erosion, and declining sand deposits due to mining.…”

The development of the Raster-based Probability Flood Inundation Model (RProFIM) approach for flood modelling in the upstream Citarum Watershed, West Java, Indonesia

“…These will affect the condition of surface runoff due to increasing rainfall intensity. The higher the surface runoff, the higher the ood risk level in the watershed (Szwagrzyk et al 2018;Chaudhary and Pandey 2022). Land degradation within the watershed can also affect the level of ooding due to changes in LULC.…”