Hydrometeorological analysis of the 12 and 13 September 2019 widespread flash flooding in eastern Spain

On 12 and 13 September 2019, a long-lasting heavy precipitation episode (HPE) affected the València, Murcia and Almería regions in eastern Spain. Observed rainfall amounts were close to 500 mm in 48 h, being the highest cumulative precipitation registered in some rain-gauges for the last century. Subsequent widespread flash flooding caused seven fatalities and estimated economical losses above 425 million EUR. High-resolution precipitation estimates from weather radar observations and flood response from stream-gauges are used in combination with a fully-distributed hydrological model to examine the main hydrometeorological processes within the HyMeX program. This HPE was characterized by successive, well-organized convective structures that impacted a spatial extent of 7500 km2, with rainfall amounts equal or larger than 200 mm. The main factors driving the flood response were quasi-stationarity of heavy precipitation, very dry initial soil moisture conditions and large storage capacities. Most of the examined catchments exhibited a dampened and delayed hydrological response to cumulative precipitation: Until runoff thresholds were exceeded, infiltration-excess runoff generation did not start. This threshold-based hydrological behaviour may impact the shape of flood peak distributions, hindering strict flood frequency statistical analysis due to the generally limited lengths of data records in arid and semi-arid catchments. As an alternative, simple scaling theory between flood magnitude and total rainfall amount is explored.

Flood Response and Civil-Military Coordination in Pakistan

It is an established fact that Pakistan is prone to disasters and damage caused by these disasters is immeasurable and varies with the geographical location, climate, and type of earth surface, geology and degree of vulnerability. The paper focus on underpinnings of flood response, however, emphasis will be on role of Corps of Engineers (Army), Civil-Military coordination in 2010 Floods and prolonged employment of Army on such tasks. The main focus of this paper is on the existing role of military, their relationship with the civil set-up and the expectations of both the group from each other. Moreover, this paper also reviews about the existing frameworks and mechanisms of coordination between the two groups. The paper may help managers, policy makers and army engineers and government authorities to realistically evolve flood response, and decentralized mode of operation should be adapted from national to regional level in order to follow an integrated framework for bringing all stakeholders and victims together for developing an organized response system. However, the prolonged employment of Army on mitigation of disasters must be avoided.

Tools for Improved Drought and Flood Response

A new book presents recent advances in the modeling and remote sensing of droughts and floods of use to emergency response organizations and policy makers on a global scale.

The impact of the spatiotemporal structure of rainfall on flood frequency over a small urban watershed: an approach coupling stochastic storm transposition and hydrologic modeling

The role of rainfall space–time structure, as well as its complex interactions with land surface properties, in flood response remains an open research issue. This study contributes to this understanding, specifically for small (<15 km2) urban watersheds. Using a flood frequency analysis framework that combines stochastic storm transposition (SST)-based rainfall scenarios with the physically based distributed Gridded Surface Subsurface Hydrologic Analysis (GSSHA) model, we examine the role of rainfall spatial and temporal variability in flood frequency across drainage basin scales in the highly urbanized Dead Run watershed (14.3 km2), Maryland, USA. The results show the complexities of flood response within several subwatersheds for both short (<50 years) and long (>100 years) rainfall return periods. The impact of impervious area on flood response decreases with increasing rainfall return period. For extreme storms, the maximum discharge is closely linked to the spatial structure of rainfall, especially storm core spatial coverage. The spatial heterogeneity of rainfall increases flood peak magnitudes by 50 % on average at the watershed outlet and its subwatersheds for both small and large return periods. The framework of SST–GSSHA-coupled frequency analysis also highlights the fact that spatially distributed rainfall scenarios are needed in quick-response flood frequency, even for relatively small basin scales.

Health sector’s flood response plan: A comprehensive review

Background: Floods are the most common natural disaster which may have substantial impacts on the human health and life and the environment. In recent years, Iran have faced many floods and it seems that increasing impacts of floods in Iran are attributed to inadequate preparation and no well-established strategies and guidelines for response by health sector and other related response organizations. So, this study was conducted to review the current plans in the world to identify the required elements of the flood emergency response plan to prevent its consequences on the health sector in Iran. Methods: A comprehensive review was performed through search on electronic data bases, including, Medline, Scopus, ProQuest, and e-journals which were accessible during 2010-2020. The keywords were response plan, flood, requirements, guidelines, and health sector. Data were collected using data extraction form and analyzed through content analysis. Results: In the initial search, 960 possible sources of flood response were identified. After excluding duplicate papers and the documents that did not contribute to the flood response plan, 64 articles and programs or guidelines that all them has been reviewed, were obtained. The findings were divided into two groups, response prerequisites and response activities. Conclusion: This review provided a complete view of the flood consequences for the health sector and allows professionals to incorporate facets of the health effect of floods into a flood response plan. The flood response plan was divided into two general categories: Initial and specific, each of which plays an important role in preventing the negative effects of the floods.

The role of storm movement in controlling flash flood response: an analysis of the 28 September 2012 extreme event in Murcia, southeastern Spain

Flash flooding is strongly modulated by the spatial and temporal variability in heavy precipitation. Storm motion prompts a continuous change of rainfall space-time variability that interacts with the drainage river system, thus influencing the flood response. The impact of storm motion on hydrological response is assessed for the 28 September 2012 flash flood over the semi-arid and medium-sized Guadalentín catchment in Murcia, southeastern Spain. The influence of storm kinematics on flood response is examined through the concept of ‘catchment-scale storm velocity’. This variable quantifies the interaction between the storm system motion and the river drainage network, assessing its influence on the hydrograph peak. By comparing two hydrological simulations forced by rainfall scenarios of distinct spatial and temporal variability, the role of storm system movement on the flood response is effectively isolated. This case study is the first to: (i) show through the catchment-scale storm velocity how storm motion may strongly affect flood peak and timing; and (ii) assess the influence of storm kinematics on hydrological response at different basin scales. In the end, this extreme flash flooding provides a valuable case study of how the interaction between storm motion and drainage properties modulate hydrological response.

The Policy Design on Preparation and Coping with Flash Flood Mekong River Basin Entrance Inequality Deduction Form Disaster: A Case Study of Mueang Nong Khai District Nong Khai Province, Thailand

The objective of this research is (1) to raise awareness and prepare for flash flooding among people in the Mekong region which promotes inequality reduction from disasters by using Muang Nong Khai District, Nong Khai Province as a model area, and (2) To develop a policy proposal by designing a joint policy for flash flood preparedness in the Mekong region to promote inequality reduction from disasters. This research is action research in conjunction with policy design focusing on brainstorming. Group discussions with in-depth interviews. The research results were found that: [A] People have a basic understanding of (1) the nature of the disaster, and (2) the experience of the flash flood disaster encountered by the WiangKhuk Sub-district people is about remembering the severity Looking at the floods that have been associated, but in terms of preparation, community leaders see together that they want to develop into a system and plan for a joint rehearsal in the future. [B] Flash flood response weaknesses are (1) Weaknesses for early warning, evacuation, and flash flood drills, (2) Weaknesses of flash flood plans for areas that have not yet been formally planned, And (3) weaknesses in communication. [C] The interesting common policy design guidelines that should be developed are (1) Flash flood knowledge development, (2) direction and coordination for emergency operations, (3) agreements that Formal and informal for flash flood response, (4) resource mobilization focused on the certainty of emergency work. [D] The policy recommendations are: (1) Appropriate policy guidelines for flash flood preparedness in the Mekong River Basin should include precautions, evacuation, flash flood drills, and community-level plans to tackle flash floods. (2) The public sector, civil society, and communities should jointly develop policies to prepare for flash floods, that is, to develop flash flood knowledge to keep up with the changing circumstances of the local context. (3) The key policy to deal with flash floods to help reduce inequality is to develop community capacity or community potential. This is a collaboration of community organizations, the government sector, civil society in the area, which together with driving a community-level response plan. [E] The operation recommendations include (1) the community must be the host to invite government organizations such as the Provincial Disaster Prevention and Mitigation and the Mekong Community Organization Council to drive community-level planning. (2) Organizing a network meeting on flash flood response such as communities, Provincial Disaster Prevention and Mitigation Agency, and Mekong Community Organization Council should hold meetings at least twice a year to understand the situation and implement measures to deal with flash floods in a timely manner. (3) Flash flood drills should be conducted at least once a year in order to build mutual learning among communities and networks in flash flood preparedness, it is also an analysis of the weaknesses each year and can be used to develop the capacity and capacity of the community to handle the flash flood in the future.

The impact of spatiotemporal structure of rainfall on flood frequency over a small urban watershed: an approach coupling stochastic storm transposition and hydrologic modeling

The role of rainfall space-time structure, as well as its complex interactions with land surface properties, in flood response remains an open research issue. This study contributes to this understanding, specifically in small (< 15 km2) urban watersheds. Using a flood frequency analysis framework that combines stochastic storm transposition-based rainfall scenarios with the physically-based distributed GSSHA model, we examine the role of rainfall spatial and temporal variability in flood frequency across drainage scales in the highly-urbanized Dead Run watershed (14.3 km2) outside of Baltimore, Maryland, USA. The results show the complexities of flood response within several subwatersheds for both short (< 50 years) and long (> 100 years) rainfall return periods. The impact of impervious area on flood response decreases with increasing rainfall return period. For extreme storms, the maximum discharge is closely linked to the spatial structure of rainfall, especially storm core spatial coverage. The spatial heterogeneity of rainfall increases flood peak magnitudes by 50 % on average at the watershed outlet and its subwatersheds for both small and large return periods. The results imply that commonly-made assumption of spatially uniform rainfall in urban flood frequency modeling is problematic even for relatively small basin scales.