Conference PaperPDF Available

FLOOD EViDENS: A WEB-BASED APPLICATION FOR NEAR-REAL TIME FLOOD EVENT VISUALIZATION AND DAMAGE ESTIMATIONS

Authors:

Abstract and Figures

The Web-based Near-real Time Flood Event Visualization and Damage Estimations (Flood EViDEns) is an online geo-visualization application developed through the Phil-LiDAR 1 project of Caraga State University. The application is targeted to be utilized by the Local Government Units (LGUs) and communities in the Caraga Region, Mindanao, Philippines to assist them in geospatially informed decision making in times of flood disasters. The application is an amalgamation of web mapping technology, various geospatial datasets including LiDAR-derived elevation and information products, hydro-meteorological data, and flood simulation models to visualize in near-real time the current and possible future extent of flooding and its associated damages to infrastructures. The Flood EViDEns application facilitates the release and utilization of this near-real time flood-related information through a user-friendly front end interface consisting of web map and tables. The application's back-end consists of computers running flood simulation models and geospatial analysis to dynamically produce (in an automated manner) current and future flood extents, and tabulated information on the structures affected by flooding including hazard types. These outputs are forwarded into a PostgreSQL/PostGIS spatial database where it is accessed by the front end interface for web visualization. The information provided by Flood EViDEns is very important especially to the LGUs and the community as it can increase awareness and responsiveness of the public to the impending flood disaster. Providing this kind of information during a heavy rainfall event is useful as it could assist in preparation for evacuation, in easily identifying areas that need immediate action, in identifying areas that should be avoided, and in estimating the severity of damage to people and infrastructure as flooding progresses.
Content may be subject to copyright.
FLOOD EViDENS: A WEB-BASED APPLICATION FOR NEAR-REAL TIME FLOOD
EVENT VISUALIZATION AND DAMAGE ESTIMATIONS
Jojene R. Santillan, Edsel Matt O. Morales and Meriam Makinano-Santillan
CSU Phil-LiDAR 1, College of Engineering and Information Technology, Caraga State University, Ampayon,
Butuan City, 8600, Philippines,
Email: santillan.jr2@gmail.com,
KEY WORDS: Flood, hazard, visualization, decision support, disaster preparedness
ABSTRACT: The Web-based Near-real Time Flood Event Visualization and Damage Estimations (Flood
EViDEns) is an online geo-visualization application developed through the Phil-LiDAR 1 project of Caraga State
University. The application is targeted to be utilized by the Local Government Units (LGUs) and communities in
the Caraga Region, Mindanao, Philippines to assist them in geospatially informed decision making in times of
flood disasters. The application is an amalgamation of web mapping technology, various geospatial datasets
including LiDAR-derived elevation and information products, hydro-meteorological data, and flood simulation
models to visualize in near-real time the current and possible future extent of flooding and its associated damages
to infrastructures. The Flood EViDEns application facilitates the release and utilization of this near-real time flood-
related information through a user-friendly front end interface consisting of web map and tables. The application's
back-end consists of computers running flood simulation models and geospatial analysis to dynamically produce
(in an automated manner) current and future flood extents, and tabulated information on the structures affected by
flooding including hazard types. These outputs are forwarded into a PostgreSQL/PostGIS spatial database where it
is accessed by the front end interface for web visualization. The information provided by Flood EViDEns is very
important especially to the LGUs and the community as it can increase awareness and responsiveness of the public
to the impending flood disaster. Providing this kind of information during a heavy rainfall event is useful as it could
assist in preparation for evacuation, in easily identifying areas that need immediate action, in identifying areas that
should be avoided, and in estimating the severity of damage to people and infrastructure as flooding progresses.
1. INTRODUCTION
Flood-related disasters in the Philippines have become more pronounced in recent years, majority of which have
been caused by tropical storms and low pressure systems which bring along rains of varying duration, volume and
intensity. An infamous example would be that of Tropical Storm (TS) Ondoy (International name: Ketsana;
September 2007) which dumped a month's worth of rain in less than 24 hours and caused flooding in Metro Manila,
killing at least 300 people and displacing another 700,000 (Cheng, 2009). Since then, similar flooding occurrences
became frequent and more intense, and has continued to negatively impact and bring costly damages to human
lives and properties such that Local Government Units (LGUs) are now using flood susceptibility and hazard maps
as part of their flood disaster risk reduction and management activities. Presently, most of the LGUs rely on Mines
and Geosciences Bureau (MGB) flood susceptibility maps (http://gdis.denr.gov.ph/mgbgoogle/), and if available,
the flood hazard maps generated through the Project Nationwide Operational Assessment of Hazards (NOAH) and
displayed in its website (http://noah.dost.gov.ph; Lagmay, 2012) in their flood hazard assessment activities.
However, these hazard maps are static and only represent specific flooding scenarios. In the Project NOAH
website, near-real time flood extent maps (i.e., flood extent maps that are generated and displayed as it happens)
and rainfall scenario-based flood hazard maps derived through the use of flood model simulation models and Light
Detection and Ranging (LiDAR) topographic datasets are also available but only for limited number of areas.
Although the flood susceptibility maps provided by MGB and the online flood maps in Project NOAH are
important sources of information necessary for flood hazard assessments, some enhancements and additional
functionalities are necessary to generate additional information that can aid LGUs in geospatially-informed
decision-making before, during and after a flood disaster. These enhancements and additional functionalities may
include the following:
The capability to generate publicly-accessible near-real time flood hazard maps (as flooding progresses),
especially during occurrence of heavy to torrential rainfall events. Currently, only flood extent (no hazard
level categorization) maps are available online in near-real time in the Project NOAH website.
The capability to generate publicly-accessible forecasted flood hazard maps (i.e., expected flooding in the
next hours or days)
2655
36th Asian Conference on Remote Sensing 2015 (ACRS 2015), Quezon City, Philippines, Volume 4, pp. 2655-2664, 2015
The capability to analyze and estimate in near-real time the possible damages (e.g., counting of affected
structures according to hazard levels) caused by flooding events.
The above capabilities can be useful in localized flood disaster management as it can assist in careful planning and
preparation of evacuation strategies, in easily identifying areas that need immediate action, in identifying areas that
should be avoided, and in estimating the severity of damage to people and infrastructure as flooding progresses.
In this paper, we present how these capabilities can be realized through the development of the web-based Near-
real Time Flood Event Visualization and Damage Estimations (Flood EViDEns) application. Flood EViDEns is an
application developed under the Caraga State University Phil-LiDAR 1 project that utilizes LiDAR-derived
elevation and information products as well as other elevation datasets, water level records by monitoring stations,
and flood simulation models to visualize in near-real time the current and possible future extent of flooding (and its
associated damages to infrastructures) due to occurrence of a rainfall event, including various flooding scenarios
caused by rainfall events of varying duration and intensity.
The conceptual framework, design and implementation of this application are discussed in the following sections.
2. CONCEPTUAL BASIS
The concept for Flood EViDEns is an expanded version of the design concept used in the development of theI aM
AWaRe: An Online Geo-visualization Tool for Inundation Monitoring And Water Level Forecasting in Rivers
web application (Santillan, 2013).
There are several sets of information that maybe used to properly manage an impending flood disaster. Among
them are:
1. Information on the current extent and levels of flooding along a water body (in this case, a river) and the
areas that are presently flooded;
2. Forecasts on how water level will rise (or recede) at different locations along the river as rainfall events
occur in the upstream watersheds;
3. Information on the expected extent and levels of flooding based on the forecasted increase/decrease in
water levels;
4. Information on the estimated number of structures (e.g., buildings) that are affected or can possibly be
affected by the current and forecasted flooding, including their locations.
The first set can be obtained by direct observation (e.g., visiting the areas affected, taking pictures) - but this is
often difficult and risky especially if the flooding situation has already elevated. Alternatively, flood simulation
models can be used to estimate the current extent and depth of flooding by utilizing water level and rainfall
recorded by monitoring stations as inputs. Based on rainfall data records for the past hours or days, the flood
model, through its hydrologic component, can compute how much flood water has been generated from the
upstream watersheds. Then, the model‟s hydraulic component can simulate how this flood water has traveled
towards the downstream areas, including how it overflows, up to the current time. The flood information produced
by the flood models can be converted into flood depth and hazard maps showing the information on the current
extent and levels of flooding in an area through the use of Geographic Information System (GIS) tools and
techniques,
The second and third sets of information can also be obtained by the use of flood simulation models. Since the
effect of a rainfall event in making water level rise in rivers is not immediate (usually takes hours before it is felt
downstream especially if much of the flood water will come from upstream watersheds), it is then possible to make
a forecast on how water will rise or recede at different locations along the river, and to predict in advance the
possible flooding levels and extents. The flood model simulations will just have to be extended to a period of
several hours or days from the current time in order to generate the forecasts.
2656
36th Asian Conference on Remote Sensing 2015 (ACRS 2015), Quezon City, Philippines, Volume 4, pp. 2655-2664, 2015
The fourth set of information, which
may be considered as the most important
in flood hazard assessment, can be
obtained through GIS-based analysis of
the flood maps together with additional
spatial datasets such as an exposure geo-
database of buildings and other
infrastructures. By spatially overlaying
the flood hazard maps with the data of
buildings and other structures, those
structures affected by flooding can be
located, and the their numbers can be
summarized according to flood hazard
levels (e.g., if these structures are in low,
medium or high levels of hazards).
Based on the above discussions,
obtaining the four sets of information
needed for flood disaster management is
possible because there are available
tools and techniques to generate this
information. The challenge, however, is
how to generate this information in a
timely manner, and make them
accessible to disaster managers or even
to affected communities for it to be
useful in managing flood disasters. It is
on this challenge that the Flood
EViDEns application was built upon.
3. AREA OF APPLICATION
The test area of application is the
Cabadbaran River Basin (CRB) and the
nearby Pandanon River and Caasinan
River Watersheds in Agusan del Norte,
Caraga Region (Figure 1). With a total
area of 238 km2, these river basins and
watersheds cover a major portion of
Cabadbaran City which was reported to
be one of those affected by flooding during the onslaught of tropical storms Agaton and Seniang in the year
2014. These flooding incidents make the city an ideal site for the development of the application, and to illustrate
how the application can be useful during flood events.
4. DESIGN AND DEVELOPMENT
Flood EViDEns is envisioned to be a web platform where disaster managers, LGUs and the community can easily
access the four sets of localized flood hazard information (cited and explained in the previous section) for near-real
time assessment and geo-spatially informed decision making. These decisions may be related to (i.) providing
appropriate early warning to possible communities that could be affected by flooding, (ii.) locating and estimating
the number of affected communities; (iii.) preparations and formulation of advisories necessary for evacuations;
and (iv.) relief operations, among others.
To make this possible, the application was designed and developed with three major components:
Flood information generation
Figure 1. The test area of application which is the Cabadbaran
River Basin (CRB) and the nearby Pandanon River and Caasinan
River Watersheds in Agusan del Norte, Caraga Region
2657
36th Asian Conference on Remote Sensing 2015 (ACRS 2015), Quezon City, Philippines, Volume 4, pp. 2655-2664, 2015
Information storage
Online visualization/web platform
4.1 Flood Information Generation Component (IGC)
The IGC consist of computer workstations running flood simulation models to generate near-real time flood
information that includes the current and forecasted flood inundation extent and flood hazard levels, and water level
forecasts. The flood simulation software/programs used are the Hydrologic Engineering Center Hydrologic
Modelling System (HEC HMS) version 3.5 and HEC River Analysis System (HEC RAS) version 4.1. Various
geospatial datasets were utilized in the development of flood simulation models (Figure 2). In HEC HMSmodel
development, a 10-m Synthetic Aperture Radar (SAR) Digital Elevation Model (DEM) was used for sub-basin
delineations and for derivation of topography-related parameters of the model such as slope and elevation. Images
acquired by the Landsat 8 satellite were also utilized to derive a landcover map using Maximum Likelihood
classification. The landcover map is necessary for the derivation of land-cover-related model parameters such as
surface roughness coefficient, and runoff/infiltration capacities. River width and cross-section data obtained from
field surveys as well as those extracted from 1-m resolution LiDAR-derived Digital Terrain Model (DTM) were
also used to estimate the channel routing parameters of the model. For HEC RAS model development, river bed
topography (obtained from bathymetric surveys), sea bed topography (obtained from a NAMRIA topographic
map), LiDAR DTM, building footprints (with top elevation) extracted from LiDAR Digital Surface Model (DSM),
and the same landcover map derived from Landsat 8 OLI satellite image were used as major inputs.
The HEC HMS-based hydrologic model computes for the volume of water coming from the upstream watersheds
caused by rain falling in these areas. Rainfall depths recorded by rain gauges within and in the vicinity of the river
basin are being used as input into the HEC HMS to
compute discharge hydrographs for specific locations in the
river basin, specifically at those locations where the
upstream watersheds ends and the floodplain portions
begin. The discharge hydrographs depict the volume of
water per unit time (in m3/s) that drains into the main river
at these locations. These hydrographs are then used as basis
to generate water level forecasts, and as inputs into the
HEC RAS hydraulic model to generate the flood depth and
hazard maps (for the current and forecasted flood events).
HEC RAS is a one-dimensional flood model that utilizes
river and flood plain geometric data (from topographic and
hydrographic surveys and LiDAR Digital Terrain Model -
DTM), land-cover and surface roughness (from remotely-
sensed images), and discharge hydrographs in order to
compute water levels all throughout the river. Once these
water levels are computed, the flooded or inundated areas
along the river and in the floodplains are estimated by
intersecting the water surface profiles into a high resolution
LiDAR DTM. This is done through the “RASMapper”, the
GIS module of HEC RAS. This process generates a flood
depth map, which is further processed to generate flood
hazard levels by categorizing flood depths into low (depth
<0.5 m), medium (0.5 ≤ depth 1.5 m), and high (depth >
1.5 m) hazards. The flood hazard maps produced from this
process are in GIS shapefile format (one file each for the
current flood hazard map, and forecasted flood hazard
map), and are forwarded to the Information Storage
Component.
Since the aim is to provide the latest and forecasted flood information in near-real time, the flood simulations were
automated using a combination of Python, wget, AutoIT and batch scripts. The automation includes downloading
rainfall and water level data from an online data server/repository, formatting these datasets into HEC HMS and
HEC RAS usable files, running the HEC HMS and HEC RAS models, generating the flood hazard map shapefiles,
extracting the water level forecasts from the HEC HMS simulation results and exporting to tabular text files, and
Figure 2. Some of the geospatial datasets used
in the development of the flood models.
2658
36th Asian Conference on Remote Sensing 2015 (ACRS 2015), Quezon City, Philippines, Volume 4, pp. 2655-2664, 2015
then storing all of them into a spatial database (in the Information Storage Component). This whole process is
repeated every 10-minutes through Windows Task Scheduler. It should be noted that flood hazard maps and water
level forecasts are generated by running the HEC HMS model with a simulation period starting five days before the
current time up to the next six hours. The forecasted flood hazard map represents the maximum extent and level of
flooding with the next six hours.
In addition to the near-real time flood hazard maps, scenario-based flood hazard maps were also generated using
the HEC HMS and HEC RAS models, and stored in the spatial database. These scenarios represent maximum
flooding caused by rainfall events of varying duration and intensity (e.g., rainfall events with return periods of 2, 5,
10, 25, 50, and 100 years). Each of these scenarios is characterized by specific amounts of accumulated rainfall in a
24-hour duration that can cause flooding. Including these scenario-based flood hazard maps in Flood EViDEns can
aid rapid flood hazard assessment and damage estimation using only the amount of 24-hour accumulated rainfall as
indicator (e.g., if a user knows the amount of rainfall accumulated in the last 24 hours, he/she can make
assessments and estimations by selecting one of the scenario-based flood hazard map that correspond to the amount
of accumulated rainfall).
4.2 Information Storage Component
Once the water level forecast text files and GIS files have been generated by the flood models, they are
automatically stored and loaded into a PostgreSQL database extended with the PostGIS plugin to handle and
support geographic objects (e.g., shapefiles). This spatial database is configured in a data server connected to the
internet.
4.3 Online Visualization/Web Platform
The online visualization/platform for Flood EViDEns is a webpage configured using Bootstrap and Javascripts to
display maps of flood hazards and affected structures as well as processed textual information (e.g., statistics of
affected structures) coming from the PostgreSQL (PostGIS) spatial database. Basically, the webpage has three
major functional segments: (i.) generalized flood hazard information segment; (ii) a web map segment; and (iii.)
localized flood hazard information segment.
The generalized flood hazard information segment allows the user to display a summary of the number of structures
affected by a flooding event. For example, a user can select a certain flood event and then send a query to the
spatial database to display the statistics of structures affected by the selected flood event. The query and the display
of information is handled using GeoDjango framework, i.e., by performing a query (intersects or ST_Intersects in
PostGIS) using Django Object-relational mapping (ORM). If a certain structure intersects the flood hazard layer, it
will be counted (considered as affected) depending on what hazard level it intersected. There are some cases in
which a structure intersects multiple times with a flood hazard layer with different hazard level e.g. in medium and
high hazard levels. In that instance, the structure will be counted according to the highest hazard level it intersects.
The web map segment displays flood hazard, structures (buildings), water level forecast location, and other
associated layers (e.g., political boundaries). The visualization of these layers is a two-step process. First, the map
layers requested by the user are accessed and processed (published) by GeoServer Web Map Service (WMS). Then,
the display/rendering of these layers is handled by OpenLayers. In the web page, the user can select which layers to
display. For example, a user can display both the near-real time flood hazard map as well as location of affected
structures which are color-coded according to hazard level. The categorization/color-coding of the affected
structures according to hazard levels is handle using GeoDjango framework (for the query, e.g., for determining the
hazard level of a structure by spatially intersecting the structures layer with the flood hazard layers) and
Geoserver (for the visualization). The Water Level Station layer is also included in the web map segment. When
activated, the user can view the graph of water level and rainfall records in the last 24 hours, and the forecasted
water level for the next 6 or more hours. The information is rendered using HighCharts and Javascripts.
The localized flood hazard information segment is designed to have Search/Filter utility where the user can
search flood affected structures according to barangay and type of structure. The resulting list categorizes the
structures according to flood hazard level, and if clicked, the user can see the actual location of these structures in
the web map (e.g., the structures location is zoomed-in in the map). The generation of the detailed list is also
handled using GeoDjango framework.
2659
36th Asian Conference on Remote Sensing 2015 (ACRS 2015), Quezon City, Philippines, Volume 4, pp. 2655-2664, 2015
5. RESULTS/IMPLEMENTATION OF THE APPLICATION
There are two versions of Flood EViDEns currently available: full version (available at the CSU Phil-LIDAR 1
Project Office in Caraga State University) and the initial, public version (available at http://121.97.192.11:8082).
In the full version, the user can access near-real time flood hazard map information. However, this functionality is
not yet fully tested and its enhancement is on-going. This is the reason why it has not yet been included in the
public version.
Figure 3 shows the user interface of the application as accessed through a web browser, with the three segments of
the application indicated.
To use the application, the user can start by selecting a flood event in the generalized flood information segment.
Clicking the Show button will display the list of affected structures categorized according to flood hazard levels
(Figure 4).
To view the flood hazard maps and other information, the user can click the desired flood hazard layers on the left
side of the web map segment (Figure 5).
A localized search of flood affected structures (based on the currently displayed flood hazard information) can be
done by the user by doing a selection according to municipality, barangay, and type of structure (Figure 7).
The water level forecast function of the application can be activated by first, enabling the Water Level Station
layer in the Overlays section, and then clicking on the water level station in the web map to display the water level
forecasts (Figure 8).
2660
36th Asian Conference on Remote Sensing 2015 (ACRS 2015), Quezon City, Philippines, Volume 4, pp. 2655-2664, 2015
Figure 3. Interface of Flood EViDEns as accessed through a web browser.
Generalized Flood Hazard Information
Segment
Localized Flood Hazard Information Segment
Web Map Segment
2661
36th Asian Conference on Remote Sensing 2015 (ACRS 2015), Quezon City, Philippines, Volume 4, pp. 2655-2664, 2015
Figure 4. The generalized flood hazard information displayed in Flood EViDEns.
Figure 5. The web map interface, showing the flood hazards and affected structures.
2662
36th Asian Conference on Remote Sensing 2015 (ACRS 2015), Quezon City, Philippines, Volume 4, pp. 2655-2664, 2015
Figure 6. Localized flood hazard information that can be displayed in Flood EViDEns.
Figure 7. The water level forecast information available in Flood EViDEns.
6. CONCLUDING REMARKS
In this paper, we presented the development of the web-based Near-real Time Flood Event Visualization and
Damage Estimations (Flood EViDEns) application. The application is aimed to be useful in localized flood disaster
management by providing publicly-accessible near-real time flood hazard maps (as flooding progresses), especially
during occurrence of heavy to torrential rainfall events and forecasted flood hazard maps (i.e., expected flooding in
the next hours or days), including the capability to analyze and estimate in near-real time the possible damages
(e.g., counting of affected structures according to hazard levels) caused by flooding events.
2663
36th Asian Conference on Remote Sensing 2015 (ACRS 2015), Quezon City, Philippines, Volume 4, pp. 2655-2664, 2015
At present, Flood EViDEns is continuously being improved to achieve the set of objectives it was originally
designed for. A public version of the application is already accessible at http://121.97.192.11:8082. This version
will be enhanced in the following months, with the addition of fully-tested near-real time functionality.
ACKNOWLEDGEMENTS
This work is an output of the Caraga State University (CSU) Phil-LiDAR 1 project under the “Phil-LiDAR 1.
Hazard Mapping of the Philippines using LiDAR” program funded by the Department of Science and Technology
(DOST). The SAR DEM and the LiDAR DTM and DSM used in this work were provided by the University of the
Philippines Disaster Risk and Exposure for Mitigation (UP DREAM)/Phil-LIDAR 1 Program. We thank the CSU
Phil-LIDAR 2 Project and the Information Communication Technology (ICT) Center of CSU for providing us
access to their data server, as well as for their assistance in making the public version of Flood EViDEns accessible
online. We also thank all CSU-Phil-LIDAR 1 technical staff and assistants, as well as the LGUs in the Cabadbaran
River Basin for their assistance during the conduct of hydrological measurements and flood map validation surveys
which were used in the preparation and calibration of the flood models. We acknowledge the ASTI DOST for
giving us access to the near-real time rainfall and water level datasets needed by Flood EViDEns.
AUTHOR CONTRIBUTIONS
Jojene Santillan and Meriam Makinano-Santillan conceptualized the idea behind the application. The flood models
that generated the scenario-based maps and near-real time flood hazard maps and water level forecasts were
prepared and calibrated by Jojene Santillan. The applications information storage and online visualization/web
platform components were developed by Edsel Matt O. Morales. The full paper was written by Jojene Santillan and
Meriam Makinano-Santillan with contributions from Edsel Matt O. Morales.
REFERENCES
Cheng, M.H., 2009. Natural disasters highlight gaps in preparedness. The Lancet, Vol. 374, No. 969, pp. 1317-
1318.
Santillan, J., 2013. I aM AWaRe: An Online Geo-visualization Tool for Inundation Monitoring And Water Level
Forecasting in Rivers. Paper presented during the Web Contest (Webcon) 3 at the 34th Asian Conference on
Remote Sensing, ACRS 2013 Bridging Sustainable Asia, October 22, Bali, Indonesia.
2664
36th Asian Conference on Remote Sensing 2015 (ACRS 2015), Quezon City, Philippines, Volume 4, pp. 2655-2664, 2015
... The conceptual basis and overviews of the initial version of Flood EViDENs is reported in Santillan et al. (2015). However, much of what has been reported in that paper refers to the 'nearreal time' or 'dynamic' version of Flood EViDEns. ...
... Flood hazard information corresponding to various historical and hypothetical scenarios (i.e., flooding due occurrence of rainfall events of different return periods of 2, 5, 25, 50 and 100 years) were generated for each of the 12 river basins through the use of flood simulation software/programs, particularly the Hydrologic Engineering Center Hydrologic Modelling System (HEC HMS) version 3.5 and HEC River Analysis System (HEC RAS) version 5 (Makinano- Santillan and Santillan, 2015). ...
Article
Full-text available
We discuss in this paper the development, including the features and functionalities, of an open source web-based flood hazard information dissemination and analytical system called “Flood EViDEns”. Flood EViDEns is short for “Flood Event Visualization and Damage Estimations”, an application that was developed by the Caraga State University to address the needs of local disaster managers in the Caraga Region in Mindanao, Philippines in accessing timely and relevant flood hazard information before, during and after the occurrence of flood disasters at the community (i.e., barangay and household) level. The web application made use of various free/open source web mapping and visualization technologies (GeoServer, GeoDjango, OpenLayers, Bootstrap), various geospatial datasets including LiDAR-derived elevation and information products, hydro-meteorological data, and flood simulation models to visualize various scenarios of flooding and its associated damages to infrastructures. The Flood EViDEns application facilitates the release and utilization of this flood-related information through a user-friendly front end interface consisting of web map and tables. A public version of the application can be accessed at http://121.97.192.11:8082/. The application is currently expanded to cover additional sites in Mindanao, Philippines through the “Geo-informatics for the Systematic Assessment of Flood Effects and Risks for a Resilient Mindanao” or the “Geo-SAFER Mindanao” Program.
... The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XLI-B8, 2016XXIII ISPRS Congress, 12-19 July 2016 Region, Mindanao, which includes Jabonga, among many other cities and municipalities ( Figure 1). Details about the project are discussed in Makinano- Santillan and Santillan (2015). However, we provide here some salient features of the project, especially on how the project generates 1-m spatial resolution hazard maps of covered river basins. ...
... A public version of the generic application is available in http://evidens.csulidar1.info. Its development is discussed in detail in Santillan et al. (2015). ...
Article
Full-text available
In this paper, we discuss how an academe-local government partnership can lead the way for the effective use of geospatial technologies for smarter and geospatially-informed decision making before, during, and after a flood disaster. In Jabonga municipality, in the province of Agusan del Norte, in Mindanao, Philippines, two significant flooding events occurred in the year 2014 which were caused by overflowing water bodies due to continuous heavy rains. These flood events inundated populated areas, caused massive evacuation, made roads un-passable, and greatly damaged sources of incomes such as croplands and other agricultural areas. The partnership between Caraga State University and the local government of Jabonga attempts to improve localized flood disaster management through the development of web-based Near-real Time Flood Event Visualization and Damage Estimations (Flood EViDEns) application. Flood EViDENs utilizes LiDAR-derived elevation and information products as well as other elevation datasets, water level records by monitoring stations, flood simulation models, flood hazard maps, and socio-economic datasets (population, household information, etc.), in order to visualize in near-real time the current and future extent of flooding, to disseminate early warnings, and to provide maps and statistics of areas and communities affected and to be affected by flooding. The development of Flood EViDEns as the main product of the partnership is an important application of geospatial technologies that will allow smarter and geospatially-informed decision making before, during, and after a flood disaster in Jabonga.
... The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XLI-B8, 2016XXIII ISPRS Congress, 12-19 July 2016 Region, Mindanao, which includes Jabonga, among many other cities and municipalities ( Figure 1). Details about the project are discussed in Makinano- Santillan and Santillan (2015). However, we provide here some salient features of the project, especially on how the project generates 1-m spatial resolution hazard maps of covered river basins. ...
... A public version of the generic application is available in http://evidens.csulidar1.info. Its development is discussed in detail in Santillan et al. (2015). ...
Article
Full-text available
In this paper, we discuss how an academe-local government partnership can lead the way for the effective use of geospatial technologies for smarter and geospatially-informed decision making before, during, and after a flood disaster. In Jabonga municipality, in the province of Agusan del Norte, in Mindanao, Philippines, two significant flooding events occurred in the year 2014 which were caused by overflowing water bodies due to continuous heavy rains. These flood events inundated populated areas, caused massive evacuation, made roads un-passable, and greatly damaged sources of incomes such as croplands and other agricultural areas. The partnership between Caraga State University and the local government of Jabonga attempts to improve localized flood disaster management through the development of web-based Near-real Time Flood Event Visualization and Damage Estimations (Flood EViDEns) application. Flood EViDENs utilizes LiDAR-derived elevation and information products as well as other elevation datasets, water level records by monitoring stations, flood simulation models, flood hazard maps, and socioeconomic datasets (population, household information, etc.), in order to visualize in near-real time the current and future extent of flooding, to disseminate early warnings, and to provide maps and statistics of areas and communities affected and to be affected by flooding. The development of Flood EViDEns as the main product of the partnership is an important application of geospatial technologies that will allow smarter and geospatially-informed decision making before, during, and after a flood disaster in Jabonga.
... This platform is similar to the "Flood Event Visualization and Damage Estimations" or Flood EViDEns (http://evidens.csulidar1.info)" (Santillan et al., 2015). The platform was developed using a combination of web mapping data storage, visualization and analysis tools like OpenLayers, Geoserver, GeoDjango, Javascript, and PostgreSQL/PostGIS. ...
Conference Paper
Full-text available
Access to near-real time information on the spatial distribution and detailed characteristics of the current and future (forecasted) flood scenarios is crucial for effective flood forecasting and early warning, especially when formulating decisions related to evacuation and response before, during, and after a flood scenario. In this paper, we present the development and application of a web GIS platform called "Near-real Time Flood Event Visualization and Damage Estimations (NRT-Flood EViDEns) that has the capability to show detailed maps of current and forecasted flood characteristics, including the capabilities to analyze and provide maps and statistics of the impacts of flooding to various infrastructures such as buildings, roads and bridges. The flood information reported by the platform are sourced from a two-dimensional flood model based on HEC RAS 5 that utilizes high-resolution LiDAR data, satellite-derived land-cover, and near-real time hydrological and meteorological data as among its vital inputs. The 2D flood model simulates historical (last 24 hours), current, and future (next 24 hours) flood scenarios at 30-minute interval. A combination of web mapping data storage, visualization and analysis tools that include OpenLayers, Geoserver, GeoDjango, Javascript, and PostgreSQL/PostGIS are utilized to enable the user to perform flood characteristics visualization and spatial overlay analysis for impact assessment. The accuracy of the flood depths and extents generated by the platform was determined to range from 52 to 71% overall accuracies and Root Mean Square Errors ranging from 0.30 to 0.58 m based on historical flood events that were simulated. The web platform is expected to be used for operational flood monitoring and forecasting, and is envisioned to be an important tool for geo-spatially informed decision making in Butuan City.
... To support estimation of affected structures, additional layers of information such as a shapefiles of infrastructures (roads, buildings) are also imported into this database. Flood EViDEns is discussed in detail in [5], however, we describe here some of its important functionalities. ...
Conference Paper
Full-text available
An automated approach for near-real time simulation and geo-visualization of flooding, including estimation of affected infrastructures, in Lake Mainit, considered the Philippines " deepest lake is presented. Perennial flooding in several areas around the lake due to increase in the lake " s water level during the rainy season and during the passing of tropical storms exemplified the need for rapid determination of the lake " s current and future water levels, and more importantly, the depth and extent of flooding that will result from the increase in water level. The approach made use of LiDAR-derived topography of the lake " s coastal zone, lake bathymetry, near-real time lake water level and rainfall information from monitoring stations, and a hydrological model. The synergistic combination of these datasets and techniques resulted to automated and near-real time generation of current and future (forecasted) flood depths and extents, which can be viewed in a web-based geo-visualization platform. It also allows estimation of infrastructures that are affected by a current or future flooding scenario. This platform can be used as an early warning system for communities residing near the lake.
Conference Paper
Full-text available
An approach for the development of near-real time visualization and analytical tools and techniques for effective flood forecasting and early warning in the Philippines is presented in this paper. The approach aims to combines high-resolution LiDAR data, free/open source two-dimensional flood modelling/simulation software (particularly HEC RAS 5), real time hydrological and meteorological data, and web-based geo-visualization tools and techniques to develop a web-based platform that is capable of providing near-real time information on the spatial distribution and detailed characteristics of the current and future (forecasted) flood scenarios. These characteristics are the flood arrival times, flood depth, flood velocities, flood duration, and flood recession times The web-platform can show detailed maps of flood characteristics, including the capabilities to analyze and provide maps and statistics of the impacts of flooding to various infrastructures such as buildings, roads and bridges. The web platform is expected to be used for operational flood monitoring and forecasting, and is envisioned to be an important tool for geo-spatially informed decision making before, during, and after a flood disaster. It is also foreseen to be complementary to available web-based tools the Philippine government is currently using in flood disaster management.
Conference Paper
Full-text available
Rainfall has always been a factor in every flood occurrences in most, if not all, of the floodplain areas of Caraga Region, Mindanao, Philippines. Apart from its intensity, another parameter that has significant value in assessing flood incidents is the depth and velocity of the flood water. Flooding is the underlying phenomenon that the Phil-LiDAR 1 Project of Caraga State University initiated the development of an interactive web-mapping application that may be used as a tool for flood preparedness. The application was devised as one of many ways to assist the communities and Local Government Units of Caraga Region in making a sound and efficient decision in preventing and alleviating flood risks. The application requires the user to specify parameters, like municipality, barangay, amount of rainfall and to draw a polygon or point on the Web map interface, which will serve as the basis in forecasting flood risks. The application will basically provide flood information such as flood depth, flood duration and recession time and the time interval the flood water reaches the polygon or point drawn. It can also suggest safe route to the nearest evacuation shelter. Map displays and map features were built using the Openlayers API, while the extraction of data, and the flood extent calculations and analysis were JavaScript " s. Scripts retrieve the data from PostgreSQL spatial database and eventually display the tabulated information.
2013. I aM AWaRe: An Online Geo-visualization Tool for Inundation Monitoring And Water Level Forecasting in Rivers
  • J Santillan
Santillan, J., 2013. I aM AWaRe: An Online Geo-visualization Tool for Inundation Monitoring And Water Level Forecasting in Rivers. Paper presented during the Web Contest (Webcon) 3 at the 34th Asian Conference on Remote Sensing, ACRS 2013 – Bridging Sustainable Asia, October 22, Bali, Indonesia.
I aM AWaRe: An Online Geo-visualization Tool for Inundation Monitoring And Water Level Forecasting in Rivers. Paper presented during the Web Contest (Webcon) 3 at the 34th Asian Conference on Remote Sensing
  • J Santillan
Santillan, J., 2013. I aM AWaRe: An Online Geo-visualization Tool for Inundation Monitoring And Water Level Forecasting in Rivers. Paper presented during the Web Contest (Webcon) 3 at the 34th Asian Conference on Remote Sensing, ACRS 2013 -Bridging Sustainable Asia, October 22, Bali, Indonesia.