Flood 2018 and the status of reservoir-induced seismicity in Kerala, India

Ramasamy, S. M.; Gunasekaran, S.; Rajagopal, N.; Saravanavel, J.; Kumanan, C. J.

doi:10.1007/s11069-019-03741-x

Cited by 27 publications

(10 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The study suggests that if 2019 is a sign of how global warming will continue to in uence this region, changes in cloud structure, as well as the frequency and nature of severe rainfall events, might represent a danger to the Western Ghats ecosystems (Vijayakumar et al, 2021). Furthermore, several dams/reservoirs are situated across the Western Ghats, which provide water for agriculture and hydroelectric power generation (Ramasamy et al, 2019) and it is interesting to see how their opening during the extreme rainfall events aggravates the ood situation in the VBL (Mishra et al, 2018a;Sudheer et al, 2019). For example, the ood of 2018 was caused by two periods of heavy rain in two weeks; the rst of these two caused ooding along the banks of certain rivers, and water was released from just a few dams since the rain fell mostly over their catchment regions.…”

Section: Topography Siltation and Oodsmentioning

confidence: 99%

Environmental and human facets of the waterweed proliferation in a Vast Tropical Ramsar Wetland-Vembanad Lake System

Jyothibabu

Sudhakaran

Kalathil

et al. 2022

Preprint

View full text Add to dashboard Cite

The Vembanad Lake and its associated low-lying areas and network of canals (hereafter VBL) form the major part of India’s second-largest Ramsar wetland (1512 km2). Located in Kerala State on India's southwest coast, the extensive VBL has a large fishery, inland waterways, and popular tourist attractions that support the livelihoods of thousands of people. Over the last several decades, the proliferation of water weeds in the VBL has alarmingly increased, causing many adverse ecological and socioeconomic effects. Eichhornia crassipes, Monochoria vaginalis, Salvinia molesta, Limnocharis flava, Pistia stratiotes, and Hydrilla verticillata are the most troublesome water weeds in the VBL, with the first three being the most widespread. They were mostly imported to India long ago before becoming a part of the VBL. These weeds harmed water quality, waterways, agriculture, fisheries, disease vector management, as well as the vertical and horizontal shrinkage of the VBL through increased siltation and faster ecological succession. The inherently fragile VBL was harmed by extensive and long-term reclamation, the construction of saltwater barrages, and many landfill roads that crisscross water bodies serving as coastal dams, creating water stagnation. These ecological imbalances were exacerbated by excessive fertiliser use in agricultural areas, as well as the addition of nutrient-rich domestic and municipal sewage, which provided an adequate supply of nutrients and a favourable habitat for the expansion of water weeds. The recurrent floods in the VBL also favour the proliferation of water weeds, with the potential to disrupt their current distribution pattern and spread in the future.

show abstract

Section: Topography Siltation and Oodsmentioning

confidence: 99%

Environmental and human facets of the waterweed proliferation in a Vast Tropical Ramsar Wetland-Vembanad Lake System

Jyothibabu

Sudhakaran

Kalathil

et al. 2022

Preprint

View full text Add to dashboard Cite

show abstract

“…Examples are the decade-long occurrence of debris flows post the Great Wenchuan earthquake in China (2008China ( -2020; the 2016 typhoon Lionrock triggered debris flows in Hokkaido, Japan; and the 2018 extreme-precipitationinduced debris flows in Kerala, India (Zhu et al 2020, Hao et al 2020, Dai et al 2021. Extreme precipitation during 2018, 2019, and 2020 monsoons induced series of catastrophes, i.e., flash floods, landslides, and debris flows in the Western Ghats, India, resulting in more than 500 casualties and affected over 5.4 million people in 1200 towns (Mishra & Shah 2018, Ramasamy et al 2019, Sankar 2018, Ramasamy et al 2019, Vishnu et al 2019. Historically, landslides occurred extensively in many districts in the Western Ghats, both in Karnataka and Kerala.…”

Section: Introductionmentioning

confidence: 99%

Mechanisms of Initiation, Runout, and Rainfall Thresholds of Extreme-Precipitation-Induced Debris Flows

Subramanian

Yunus

Jasin

et al. 2021

Preprint

View full text Add to dashboard Cite

The frequency of unprecedented extreme precipitation events is increasing, and consequently, catastrophic debris flows occur in regions worldwide. Rapid velocity and long-runout distances of debris flow induce massive loss of life and damage to infrastructure. Despite extensive research, understanding the initiation mechanisms and defining early warning thresholds for extreme-precipitation-induced debris flows remain a challenge. Due to the nonavailability of extreme events in the past, statistical models cannot determine thresholds from historical datasets. Here, we develop a numerical model to analyze the initiation and runout of extreme-precipitation-induced runoff-generated debris flows and derive the Intensity-Duration (ID) rainfall threshold. We choose the catastrophic debris flow on 6 August 2020 in Pettimudi, Kerala, India, for our analysis. Our model satisfactorily predicts the accumulation thickness (7 m to 8 m) and occurrence time of debris flow compared to the benchmark. Results reveal that the debris flow was rapid, traveling with a maximum velocity of 9 m/s for more than 9 minutes. The ID rainfall threshold defined for the event suggests earlier thresholds are not valid for debris flow triggered by extreme precipitation. The methodology we develop in this study is helpful to derive ID rainfall thresholds for debris flows without historical data.

show abstract

“…The change in water levels of reservoir storage during extreme rainfall of Kerala in 2018 were also discussed by Ramasamy et al, Anandalekshmi et al,. The existing six major reservoirs that serve the state would have needed to have 34% more capacity to handle the heavy rainfall, and controlled release might have helped in alleviating the flood disasters [35,36]. These studies suggested that extreme heavy rainfall was the major factor behind this disastrous event and projected climate change could intensify these effects in the near future.…”

Section: Introductionmentioning

confidence: 99%

Flood inundation mapping- Kerala 2018; Harnessing the power of SAR, automatic threshold detection method and Google Earth Engine

Tiwari¹,

Kumar²,

Matin³

et al. 2020

PLoS ONE

View full text Add to dashboard Cite

Flood inundation maps provide valuable information towards flood risk preparedness, management, communication, response, and mitigation at the time of disaster, and can be developed by harnessing the power of satellite imagery. In the present study, Sentinel-1 Synthetic Aperture RADAR (SAR) data and Otsu method were utilized to map flood inundation areas. Google Earth Engine (GEE) was used for implementing Otsu algorithm and processing Sentinel-1 SAR data. The results were assessed by (i) calculating a confusion matrix; (ii) comparing the submerge water areas of flooded (Aug 2018), non-flooded (Jan 2018) and previous year's flooded season (Aug 2016, Aug 2017), and (iii) analyzing historical rainfall patterns to understand the flood event. The overall accuracy for the Sentinel-1 SAR flood inundation maps of 9th and 21st August 2018 was observed as 94.3% and 94.1% respectively. The submerged area (region under water) classified significant flooding as compared to the non-flooded (January 2018) and previous year's same season (August 2015-2017) classified outputs. Summing up, observations from Sentinel-1 SAR data using Otsu algorithm in GEE can act as a powerful tool for mapping flood inundation areas at the time of disaster, and enhance existing efforts towards saving lives and livelihoods of communities, and safeguarding infrastructure and businesses.

show abstract

Flood 2018 and the status of reservoir-induced seismicity in Kerala, India

Cited by 27 publications

References 21 publications

Environmental and human facets of the waterweed proliferation in a Vast Tropical Ramsar Wetland-Vembanad Lake System

Environmental and human facets of the waterweed proliferation in a Vast Tropical Ramsar Wetland-Vembanad Lake System

Mechanisms of Initiation, Runout, and Rainfall Thresholds of Extreme-Precipitation-Induced Debris Flows

Flood inundation mapping- Kerala 2018; Harnessing the power of SAR, automatic threshold detection method and Google Earth Engine

Contact Info

Product

Resources

About