scholarly journals One-Dimensional (1D) River Analysis of a River Basin in Southern Luzon Island in the Philippines Using Lidar Digital Elevation Model

2018 ◽  
Vol 7 (3.7) ◽  
pp. 29
Author(s):  
Fibor J. Tan ◽  
Edgardo Jade R. Rarugal ◽  
Francis Aldrine A. Uy
Keyword(s):  
Digital Elevation Model ◽  
Flood Hazard ◽  
Monsoon Season ◽  
Extreme Rainfall ◽  
The Philippines ◽  
Extreme Rainfall Events ◽  
Rainfall Events ◽  
One Dimensional ◽  
Digital Elevation ◽  
Elevation Model

Flooding is a perennial problem in the Philippines during the monsoon season intensified by the effects of typhoon. On average, there are 20 typhoons that enter the Philippine Area of Responsibility (PAR), and many of these make landfall causing catastrophic aftermath. Extreme rainfall events could lead to flooding in the downstream floodplain and landslide in mountainous terrains. In this study, which is for the case of Calumpang River that drains to the populated and developing region of Batangas City, the focus is on flooding in the floodplain areas. The river was modelled using LiDAR digital elevation model (DEM) that has an accuracy of 20cm in the vertical and 50cm in the horizontal. The result of this is river hydraulic model that can be used to accurately generate flood inundation simulations and flood hazard maps.  

scholarly journals River Flood Hazard Modeling: Forecasting Flood Hazard for Disaster Risk Reduction Planning

2019 ◽  
Vol 5 (11) ◽  
pp. 2309-2317 ◽  
Author(s):  
Murphy Ponce Mohammed
Keyword(s):  
Model Simulation ◽  
Flood Hazard ◽  
Extreme Rainfall ◽  
Base Flow ◽  
Extreme Rainfall Event ◽  
Extreme Rainfall Events ◽  
Rainfall Events ◽  
River Reach ◽  
Analysis System ◽  
Initial Base

The objective of the study is to create a flood hazard model of Tarlac River and to calibrate the model based on data gathered from the Philippine Atmospheric Geophysical and Astronomical Services Administration. The study employed analytical method wherein the 1D flood modeling was utilized. GIS, DEM data, rainfall data, river analysis system, HEC-GeoRAS, hydrologic modeling system, and HEC-GeoHMS were utilized. The different flood models revealed that Tarlac River is not expected to be overtopped by flood water as regards the different extreme rainfall events considered in the present study. The RAS model simulation was based on the concept that there is no base flow observed within the river reach before the occurrence of any extreme rainfall event. Henceforth, there is still no 100 percent assurance that the river reach will not be overtopped with the occurrence of initial base flow in combination with the occurrence of higher extreme rainfall events. Further studies or investigations should be delved into such combination of events. Possible levee breach of the Tarlac River as well as the possible incorporation of flood mitigating interventions in future modeling scenarios can be likewise considered.

Floodplain Delineation Based on Analysis of Digital Elevation Model, Soil Maps and Occurrence of Quaternary Formations

2019 ◽  
Vol 31 (1) ◽  
pp. 29-47
Author(s):  
Aleksandra Kozłowska
Keyword(s):  
Digital Elevation Model ◽  
Flood Hazard ◽  
Hazard Maps ◽  
National Research Institute ◽  
Model Soil ◽  
Main River ◽  
Digital Elevation ◽  
Elevation Model ◽  
Floodplain Delineation ◽  
Mountainous River

Abstract This paper presents a GIS based method of indicating flood extent in a mountainous river basin. Only main river with the valley is object of this analysis. The approach used in this work combines analysis of digital elevation model (DEM) obtained from LIDAR data with presence of alluvial soils and quaternary formations. In addition, in this article an attempt of calculating flood wave height for delineated floodplain is presented. The results are compared with floodplains derived from one of the products of country-scale project „IT system for protection against extraordinary hazards” (ISOK) which are flood hazard maps and with the extent of The Great Flood of 1997. Indication of the area flooded during Poland’s Great Flood in July 1997 is based on the hydrological data from Institute of Meteorology and Water Management – National Research Institute (IMGW – PIB).

scholarly journals Application of an Index-Based Approach in Geospatial Techniques for the Mapping of Flood Hazard Areas: A Case of Cape Coast Metropolis in Ghana

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3483
Author(s):  
Samuel Yaw Danso ◽  
Yi Ma ◽  
Yvonne Dodzi Ami Adjakloe ◽  
Isaac Yeboah Addo
Keyword(s):  
Digital Elevation Model ◽  
Flood Hazard ◽  
Landsat 8 ◽  
Soil Drainage ◽  
Cape Coast ◽  
Geospatial Techniques ◽  
Digital Elevation ◽  
African Soil ◽  
High Flood ◽  
Elevation Model

Floods remain one of the disasters that destroy properties, livelihoods, and in extreme situations, take lives. As a way of prevention, geospatial applications have been employed in many cities to map flood zones and predict floods. For a country such as Ghana, floods have been ranked as the second fatal disaster after epidemics leading to several kinds of research to resolve them. To date, the Cape Coast Metropolis (CCM) has received little attention in terms of research, though flood cases in the area continue to escalate. This study, therefore, examines the use of geospatial techniques as tools in addressing flood problems in the CCM of Ghana. From a Digital Elevation Model, hydrologic variables were generated using the ArcGIS software (Esri, Redlands, CA, USA). The soil drainage classification for the study was generated from a downloaded African Soil Grid Drainage map, while other important factors that influenced flooding in the CCM were obtained from Landsat 8 imagery. Over 21% of the CCM was classified as high flood hazard zones with areas around the river Kakum estuary being flood hotspots. It is, therefore, recommended that the CCM Assembly fund dredging of streams/rivers and promote afforestation along river banks to reduce the risk of flooding within the metropolis.

Developing an integrated urban inundation flood model for extreme rainfall events with complex sewer system

2020 ◽  
Author(s):  
Lea Dasallas ◽  
Hyunuk An
Keyword(s):  
Extreme Rainfall ◽  
The Philippines ◽  
Surface Model ◽  
Flood Inundation ◽  
Flood Events ◽  
Intense Rainfall ◽  
Sewer System ◽  
Urban Flood ◽  
Extreme Rainfall Events ◽  
Rainfall Events

<p>One of the major consequences of the changing climate is more intense rainfall episodes in climate vulnerable countries, specifically the Philippines. For over the last 10 years, extreme rainfall events had occurred in the country’s capital city, Metro Manila, which resulted to severe urban flooding occurrences.  The intense rainfall combined with the domain’s low elevation, close proximity to large water sheds and river basins, lack of proper urban planning and the un-systematized drainage system had aggravated the flood inundation. Numerous studies were conducted that had used flood models, but none of these had incorporated the effect of water drainage network, which is an integral part of simulating realistic urban flood inundation. Therefore, this research aims to develop an integrated urban inundation model based on digital surface model that assimilates the sewer system applicable for urban domains with complex pipe network. The quadtree shallow water method, a model that provides flexible grid generation that utilizes adaptive quadtree grid and cut method.  The results were analyzed and compared with the validation data obtained from previous extreme rainfall events. The integrated model was also compared to the existing flood inundation methodologies being used for the present flood early warning system. Research results show that present methodology is closer to the validated results as compared to the previous models. The developed model is also perceived to be best applicable for short term flood events. This shows the efficiency of utilizing integrated urban flood modeling in the Philippines, which can be used for extreme and conventional urban flood events in the future.</p>

scholarly journals Topology and seasonal evolution of the network of extreme precipitation over the Indian subcontinent and Sri Lanka

2014 ◽  
Vol 21 (4) ◽  
pp. 901-917 ◽  
Author(s):  
V. Stolbova ◽  
P. Martin ◽  
B. Bookhagen ◽  
N. Marwan ◽  
J. Kurths
Keyword(s):  
Complex Network ◽  
Extreme Precipitation ◽  
Indian Subcontinent ◽  
Monsoon Season ◽  
Extreme Rainfall ◽  
Eastern Ghats ◽  
The Tibetan Plateau ◽  
Extreme Rainfall Events ◽  
Rainfall Events ◽  
Post Monsoon

Abstract. This paper employs a complex network approach to determine the topology and evolution of the network of extreme precipitation that governs the organization of extreme rainfall before, during, and after the Indian Summer Monsoon (ISM) season. We construct networks of extreme rainfall events during the ISM (June–September), post-monsoon (October–December), and pre-monsoon (March–May) periods from satellite-derived (Tropical Rainfall Measurement Mission, TRMM) and rain-gauge interpolated (Asian Precipitation Highly Resolved Observational Data Integration Towards the Evaluation of Water Resources, APHRODITE) data sets. The structure of the networks is determined by the level of synchronization of extreme rainfall events between different grid cells throughout the Indian subcontinent. Through the analysis of various complex-network metrics, we describe typical repetitive patterns in North Pakistan (NP), the Eastern Ghats (EG), and the Tibetan Plateau (TP). These patterns appear during the pre-monsoon season, evolve during the ISM, and disappear during the post-monsoon season. These are important meteorological features that need further attention and that may be useful in ISM timing and strength prediction.

scholarly journals Variability and trends in extreme rainfall over India

MAUSAM ◽  
2021 ◽  
Vol 67 (4) ◽  
pp. 745-766
Author(s):  
A. K. SRIVASTAVA ◽  
G. P. SINGH ◽  
O. P. SINGH
Keyword(s):  
Rainfall Intensity ◽  
Monsoon Season ◽  
Daily Rainfall ◽  
Extreme Rainfall ◽  
Extreme Rainfall Events ◽  
North Central ◽  
Rainfall Events ◽  
North West ◽  
North East ◽  
Increasing Trends

This study has been attempted to investigate the seasonal and annual trends and variations in the occurrence of extreme rainfall over different Indian region and India as a whole. Trends and variations are examined on the basis of following parameters (i) frequency and magnitude of extreme rainfall intensity (ERI) and its contribution in total rainfall (ii) highest rainfall events (iii) frequency of extreme rainfall events and days (iv) frequency of rainfall events and days with daily rainfall above 100 mm and 200 mm in a grid box (1° × 1°) over different Indian regions and India as a whole. Daily gridded rainfall data from India Meteorological Department (IMD) available at 1° × 1° resolution has been used to examine trends and variations associated with extreme rainfall events. Based on the long term 95 and 99 percentile values of daily total /maximum rainfall as a threshold for extreme rainfall intensity/events of category 1 and category 2 respectively, the trends and variations in above mentioned parameters are analyzed for the periods 1951-2007, 1951-1980 and 1981-2007.  The magnitude of highest intensity rainfall is increased over country as a whole and over peninsular India; it is found to be increased by 1% during 1981-2007 as compared to period 1951-1980. The frequency of extreme rainfall intensity (ERI) days of category 1 is found to be significant increasing (0.4 days/decade) over north central region and significant decreasing trend is found over north east region (0.5 days/decade) during the pre-monsoon season. The magnitude of 24 hours highest rainfall in a grid box is found to be significant increasing over all regions under consideration except over north east and south peninsular regions. Over the last ten years period of the present study, most of the 24 hours highest rainfall events in a grid box are seen over west peninsular region. Generalized extreme value (GEV) distribution fitted with annual highest rainfall event over the country as a whole and over different Indian region indicates an increase in magnitude of most probable 24 hours highest rainfall in a grid box during second half of the  study period over north central region of the country. Analysis also reveals an increase in frequency and severity of extreme rainfall over north west, north central and west peninsular regions during the period of 1981-2007 as compared to 1950-1980.                 Annual frequency of days and events with extreme rainfall of both categories is increased most significantly over country during the period of present study (1951-2007). Significant increasing trends in frequency of days with extreme rainfall of both categories is noticed only during the monsoon season while extreme rainfall events showed increasing trends during monsoon and winter season over country as a whole. Number of days and events with daily rainfall in any grid box above 100 mm and 200 mm is observed to be significantly increased over the country. Out of six regions, significant increasing trends  in annual number of days with rainfall above 100 mm in a grid box is observed over north central and north east  regions and for rainfall above 200 mm significant increase is observed over north west and north central regions.

Sign in / Sign up

Export Citation Format

Share Document