RIO DE JANEIRO CITY HALL
MUNICIPALSECRETARY OF SANITATION AND WATER RESOURCES
SMAR
WATER SANITATION AND DRAINAGE AUTHORITY - RIOÁGUAS
BOARD OF STUDIES AND PROJECTS
MANAGEMENT OF RESEARCH AND TECHNICAL SUPPORT
MAPPING OF FLOODING POINTS AND RAINFALL
DATA USING ARCGIS
RIO DE JANEIRO CITY - RJ - BRAZIL
2014-2015 RAINY EVENTS
Author:
Nelson Luiz de Andrade Lima
Management of Research and Technical Support
Board of Studies and Projects – RioÁguas
May 2015
RIO DE JANEIRO CITY HALL
MUNICIPALSECRETARY OF SANITATION AND WATER RESOURCES
SMAR
WATER SANITATION AND DRAINAGE AUTHORITY - RIOÁGUAS
BOARD OF STUDIES AND PROJECTS
MANAGEMENT OF RESEARCH AND TECHNICAL SUPPORT
Introduction:
During the rainy events in the city the Operational Center RIO (COR-RIO) receives
information related to the formation of flooding points that are sent by other municipal
departments linked to this system, such as the Municipal Secretary of Conservation and Public
Services – SECONSERVA, the Rio de Janeiro Traffic Engineering Company - CET-RIO, the
Municipal Undersecretary of Civil Defense (SUBDEC) and the Municipal Urban Cleaning
Company - COMLURB.
Similarly, the ALERTA-RIO system, under the responsibility of the Geotechnical Authority
of the Rio de Janeiro City - GEO-RIO, discloses the rainfall data at each event.
All these data are then compiled in the form of spreadsheets and sent to the Water
Sanitation and Drainage Authority of the Rio de Janeiro RIO-ÁGUAS for disclosure, analysis
and for being archived subsequently.
RioÁguas has recently acquired the ArcGIS software in order to start to work with
Geographic Information Systems (GIS).
With this tool it was possible to perform the intersection of hydrological data with those
related to the urban drainage system of the city by the geographical mapping of these data.
Once these data were available it was took the initiative to aggregate them, so they could
be analyzed together. This proposal has driven the development of the present work, which
aims to make an assessment of the trends and characteristics related to the formation of
drainage points that presented aspects of inefficiency of stormwater runoff
along the rainy
events throughout the year of 2014, considering its respective georeferenced mapping.
RIO DE JANEIRO CITY HALL
MUNICIPALSECRETARY OF SANITATION AND WATER RESOURCES
SMAR
WATER SANITATION AND DRAINAGE AUTHORITY - RIOÁGUAS
BOARD OF STUDIES AND PROJECTS
MANAGEMENT OF RESEARCH AND TECHNICAL SUPPORT
The phenomenon of rain:
When the water clouds coalesces and forms rain, there is the phenomenon of precipitation
which can be associated with different weather phenomena under different scales of spatial and
time development. In a general way, there may be three different types of rainfall:
- The "frontal rainfalls" that are caused by the meeting of a cold and dry mass with other hot
and humid. It comes with the rise of the warm and moist mass of air, than there is a cooling of it
that condenses and forms precipitation. They are generally of medium intensity, long duration
and reach large areas;
- The "convection rainfalls" are also called "summer rains" and are caused by intense
evaporation of wet and hot surfaces (such as forests, cities and tropical oceans). The air rises in
air parcels that cool off without exchanging heat with the outside environment during its ascent.
They are associated with the sea breeze entry in the late afternoon and usually are of great
intensity, short duration and reach small areas;
- The "orographic rainfall" occurs when moist winds rise and cool off by the meeting with a
mountain barrier, as usual on the slopes facing the sea. They are generally of low intensity, high
duration and reach small areas.
Types of Rain: Convection, Frontal and Orographic.
RIO DE JANEIRO CITY HALL
MUNICIPALSECRETARY OF SANITATION AND WATER RESOURCES
SMAR
WATER SANITATION AND DRAINAGE AUTHORITY - RIOÁGUAS
BOARD OF STUDIES AND PROJECTS
MANAGEMENT OF RESEARCH AND TECHNICAL SUPPORT
The sources of data:
Satellite Images (Frequency / Forecast = 4, 3, 2, 1 day, 6 hours our 30 minutes)
Lightnings Detection System (Frequency / Forecast = 3 minutes).
PDMAP Network (Frequency / Forecast = 5 minutes). RioÁguas Network (Monitoráguas).
RIO DE JANEIRO CITY HALL
MUNICIPALSECRETARY OF SANITATION AND WATER RESOURCES
SMAR
WATER SANITATION AND DRAINAGE AUTHORITY - RIOÁGUAS
BOARD OF STUDIES AND PROJECTS
MANAGEMENT OF RESEARCH AND TECHNICAL SUPPORT
Radar Images (Frequency / Forecast = 2 minutes).
AlertaRio System (pluviographs) (Frequency / Forecast = 15 minutes).
RIO DE JANEIRO CITY HALL
MUNICIPALSECRETARY OF SANITATION AND WATER RESOURCES
SMAR
WATER SANITATION AND DRAINAGE AUTHORITY - RIOÁGUAS
BOARD OF STUDIES AND PROJECTS
MANAGEMENT OF RESEARCH AND TECHNICAL SUPPORT
Operators working in the field (Information sent by radios and mobile phones).
Operational Center RIO (COR-RIO) and Alerta-Rio System.
The Operational Center RIO (COR-RIO) has about 500 digital cameras around the city to
give traffic operators an overview of the most important roads and crossroads. The images are
displayed on a LCD video wall of 80 m².
The information comes from all the participant departments in the system and is placed in
layers on a Google map, which allows the visualization of a wide and rapid insight into the
workings done the city in real time.
RIO DE JANEIRO CITY HALL
MUNICIPALSECRETARY OF SANITATION AND WATER RESOURCES
SMAR
WATER SANITATION AND DRAINAGE AUTHORITY - RIOÁGUAS
BOARD OF STUDIES AND PROJECTS
MANAGEMENT OF RESEARCH AND TECHNICAL SUPPORT
City Topography and Hydrography:
Groups of mountains and lowlands. Runoff and flooding points formations.
The city of Rio de Janeiro has a characteristic relief, presenting three important groups of
mountains: “Pedra Branca”, which crosses the city from east to west, the “Gericinó” at north and
“Tijuca” or “Carioca”, at east. There is a high trend to form orographic rainfall around these
mountains and because of a steepy relief and areas squeezed between the sea and the
mountain the time of concentration for the rain is usually very short which results in a very
limited time for the adoption of emergency measures related to the drainage.
RIO DE JANEIRO CITY HALL
MUNICIPALSECRETARY OF SANITATION AND WATER RESOURCES
SMAR
WATER SANITATION AND DRAINAGE AUTHORITY - RIOÁGUAS
BOARD OF STUDIES AND PROJECTS
MANAGEMENT OF RESEARCH AND TECHNICAL SUPPORT
The Need for the Mapping:
The proposal to develop a mapping work arose from the need to obtain short and longterm information. The short-term refers to urgent operational measures to be decided during the
rains and the long-term refer to the actions of structural nature to be planned after the rainy
event.
Due to the limitations of human and material resources that exist in the public service it is
necessary to seek out for an optimized service attendance. Thus, field teams need more
precise information on the locations where its operations can be more effective.
During the rainy events these teams should act quickly and accurately, in order to reduce
the impact of problems caused by floods on the population:
The Civil Defense needs to know in which places there are intense flooding, where
people at risk should be removed; CET-RIO ought to be informed about the roads blocked by
the floods, in which shall be carried out the diversion of vehicular traffic; COMLURB urge to be
updated about the points where there was accumulation of garbage and where will be the
necessity to make a cleaning and SECONSERVA the streets whose drainage network is
clogged and needs to be cleaned.
Types of cleaning service of the drainage network run by SECONSERVA.
The great challenge presented is related to the prediction of possible places subject to
floods from the data sources that the city has available, so the operators that work in the field
could be send to the places where there must be a greater urgency and need.
RIO DE JANEIRO CITY HALL
MUNICIPALSECRETARY OF SANITATION AND WATER RESOURCES
SMAR
WATER SANITATION AND DRAINAGE AUTHORITY - RIOÁGUAS
BOARD OF STUDIES AND PROJECTS
MANAGEMENT OF RESEARCH AND TECHNICAL SUPPORT
In the long term can be mentioned the work of dredging and development of projects and
execution of drainage works. Criteria could be set to indicate the locations where these services
are most necessary.
Drainage project development and
execution of cleaning services in channels.
From the analysis of recorded rainfall data would be possible to try to make a correlation
between the magnitude of physical quantities (associated to the rain) and the consequences
caused by the phenomenon of rain (formation of floods).
RioÁguas then sought to gather this data in a georeferenced mapping, making the
appropriate calculations and looking to take the first steps to develop a forecasting system and
control of flooding points that could operate in real time.
Next is schematically represented, the way how the data were collected for carrying out
the mapping with the representation of the departments involved in the process.
And yet, how was done the combination of the data used in mapping: in one side the data
obtained in the field, rain gauges network.
RIO DE JANEIRO CITY HALL
MUNICIPALSECRETARY OF SANITATION AND WATER RESOURCES
SMAR
WATER SANITATION AND DRAINAGE AUTHORITY - RIOÁGUAS
BOARD OF STUDIES AND PROJECTS
MANAGEMENT OF RESEARCH AND TECHNICAL SUPPORT
LOCATION OF
FLOODING POINTS
PLUVIOGRAPHS
DATA
Representative scheme of the data collection and departments involved.
FIELD DATA
(FLOODING
POINTS)
RAIN DATA
(PLUVIOGRAPHS)
MAPPING
Basic scheme of data extraction and combination.
RIO DE JANEIRO CITY HALL
MUNICIPALSECRETARY OF SANITATION AND WATER RESOURCES
SMAR
WATER SANITATION AND DRAINAGE AUTHORITY - RIOÁGUAS
BOARD OF STUDIES AND PROJECTS
MANAGEMENT OF RESEARCH AND TECHNICAL SUPPORT
Information Mapped
Rainfall Intensity - I
The amount of rainwater is measured in millimeter (mm). A millimeter index is equal to
one liter per squared meter.
It is measured by an instrument called rain gauge or pluviometer. The mouth of a funnel
with an known area collects the rain drops and accumulate them in a reservoir placed below the
funnel.
When the changes in time of rainfall record are wanted it is used another type of
instrument called a pluviograph, that is nothing more than a rain gauge provided with a
continuous chronological record device.
It was used as a criterion to consider an intense precipitation the the value of
15mm/15min or 25mm/30min, as the table below
DURATION
(min.)
15
30
45
60
90
120
PRECIPITATION
(mm)
15
25
35
40
46
51
It is considered that once there is the indication of a rainfall intensity above the maximum
permissible the regions that are geographically linked to this index will be susceptible to the
occurrence of flooding.
Duration of rain - D
The time that the rain remains in the precipitation phenomenon. It could be measured in
hours or minutes.
Recurrence time (Frequency - F)
Also known as Time of Return or Time of Recurrence it´s the time estimated for the
recurrence of a particular event. It is defined as the inverse of the probability of an event to be
matched or exceeded. The F unit is usually given in years.
RIO DE JANEIRO CITY HALL
MUNICIPALSECRETARY OF SANITATION AND WATER RESOURCES
SMAR
WATER SANITATION AND DRAINAGE AUTHORITY - RIOÁGUAS
BOARD OF STUDIES AND PROJECTS
MANAGEMENT OF RESEARCH AND TECHNICAL SUPPORT
It is very useful for risk analysis and design of engineering works, usually with the aim of
minimizing the harmful effects of certain natural phenomenon.
The time of recurrence or payback period to be adopted in the design flow and drainage
design of the devices should be considered as shown below:
Time of recurrence
T (years)
Type drainage device
Microdrainage - storm sewer
10
Macrodrainage - uncoated channels
10
Macrodrainage - coated channels
25
Recurrence time for the drainage devices project.
The event recurrence time is obtained from the rain intensity and duration applied to IDF
curves. If the RT of the event is lower than the RT of the design the designed system is
expected to operate properly.
Representative IDF curve of one of the 33 pluviographs (Botanical Garden).
RIO DE JANEIRO CITY HALL
MUNICIPALSECRETARY OF SANITATION AND WATER RESOURCES
SMAR
WATER SANITATION AND DRAINAGE AUTHORITY - RIOÁGUAS
BOARD OF STUDIES AND PROJECTS
MANAGEMENT OF RESEARCH AND TECHNICAL SUPPORT
Nature of Reference Data
The data that were used as reference for the analysis were selected according to the
three most relevant information related to the precipitation of rain are intensity, duration and
frequency of the rainfall event, also considering its geographical position along the various
neighborhoods of the city.
Data Mapping
After the acquisition of ArcGis program a training course for the use of the tool was
offered to RioÁguas technical team. With just the knowledge of some basic resources it was
possible to perform the mapping of the presented information.
From the reports sent by COR-RIO, with the location of flooding points reported by the
departments linked to the network, a georeferenced mapping was performed. This mapping with
visual information considers the following:
1) Rivers Network (rivers and canals) with its proper description.
2) Delimitation of sub-basins associated with the main rivers of the network.
3) Territorial distribution of rainfall indexes in blue color (maximum intensity in
mm/15min), considering the area of influence of each of the gauges and their
LEGENDA
precipitation rates.
4) Mapping
Polygons
by color grid associated to the rainfall rates (maximum intensity in
mm/15min), considering the following color scale:
INT_MAX_mm_15min
0,400000 - 5,000000
5,000001 - 10,000000
10,000001 - 15,000000
15,000001 - 20,000000
20,000001 - 25,000000
Hidrografia___Rios
5) Territorial
distribution of rainfall recurrence times (in purple) and total duration (in
Sub_Bacias_Hidrograficas
green),
by each rain gauge.
Limite_de_Bairros
6) Mapping
of flooding points formation (made by balloons with stars marking).
7) Mapping of drainage points already supervised.
RIO DE JANEIRO CITY HALL
MUNICIPALSECRETARY OF SANITATION AND WATER RESOURCES
SMAR
WATER SANITATION AND DRAINAGE AUTHORITY - RIOÁGUAS
BOARD OF STUDIES AND PROJECTS
MANAGEMENT OF RESEARCH AND TECHNICAL SUPPORT
RAINY EVENT MAPPING – JANUARY 16th 2014
LEGEND
Kilometers
Hydrography
Sub Basins
Neighborhoods Limits
RIO DE JANEIRO CITY HALL
MUNICIPALSECRETARY OF SANITATION AND WATER RESOURCES
SMAR
WATER SANITATION AND DRAINAGE AUTHORITY - RIOÁGUAS
BOARD OF STUDIES AND PROJECTS
MANAGEMENT OF RESEARCH AND TECHNICAL SUPPORT
Obtained information with mapping
The visualization of data distribution and calculations and statistical analysis performed
allowed to do some observations from the superposition of the considered input data:
- It has been found the formation of flooding points in places with lower precipitation rates
than established by the alert criteria (15mm/15min or 25mm/30min);
- There were points at which the intensity of rain could have been considered high,
according to the warning criteria, but which nevertheless has not detected any failure of the
drainage system at a single point;
- Flooding points were formed in places assisted by storm sewer even with event´s RT
smaller than 10 years and close to channels with event´s RT smaller than 25 years;
- The occurrence of floods is associated with rainfall that is distributed throughout the
territory of the city, but with an average intensity below the warning criteria of the index;
- Definition of rain gauges whose areas of influence were forming more points of flood;
- Onset of flooding points that have never been mapped before and frequency index for
each point;
- Indication of the rainfalls associated with each of the flooding points formed;
The information obtained from the mapping indicates that the criteria used to define an
alert under the geotechnical viewpoint, should not be the same as those set considering the
aspect of drainage, despite the fact that they both use information from the same network of
rain gauges. It is necessary therefore to establish proper indexes for the drainage system,
which may be obtained from the mapping.
RIO DE JANEIRO CITY HALL
MUNICIPALSECRETARY OF SANITATION AND WATER RESOURCES
SMAR
WATER SANITATION AND DRAINAGE AUTHORITY - RIOÁGUAS
BOARD OF STUDIES AND PROJECTS
MANAGEMENT OF RESEARCH AND TECHNICAL SUPPORT
Future implementations in georeferenced system
The model developed still lies in a primary stage and need to pass through future
implementations that may make it more sophisticated and accurate, being necessary for such a
large number of input data and calibration of the model.
As an example of these implementations the inclusion of the following aspects in the
modelling can be mentioned:
- Use mapping with digital elevation model processed by INPE and TOPODATA;
- Inclusion of altimetry considering a three-dimensional mapping of the relief and
hydraulic data associated with rivers and channels;
- Definition of the flow direction of rivers and channels;
- Definition of runoff coefficients (runoff) from the land use map;
- Inclusion of the implanted drainage network (as built);
- Direct linking of rainfall data to the contribution basins of the rivers and channels;
- Incorporation of tidal influence in the flow of rivers and channels that disembogue near
the shore;
- Inclusion of the information available from the monitoring system of the RIO-ÁGUAS
hydrometric network;
- Inclusion of information concerning the extension of each flood point;
- Inclusion of the data related to temperature, relative humidity and wind speed in the
period that immediately preceds each rainy event;
- Conduct hydrologic analysis with Spatial Analyst;
- Integration between archiving systems: SISARQ, SigÁguas and Geovias;
- Indication of alternate routes of traffic from the points where floods were mapped;
- Drainage Network Extraction, Algebra maps and Watershed Delimitation;
RIO DE JANEIRO CITY HALL
MUNICIPALSECRETARY OF SANITATION AND WATER RESOURCES
SMAR
WATER SANITATION AND DRAINAGE AUTHORITY - RIOÁGUAS
BOARD OF STUDIES AND PROJECTS
MANAGEMENT OF RESEARCH AND TECHNICAL SUPPORT
- developing an application that allows the field teams of technicians to
communicate with the operational center and make real-time mapping of flooding
points (using the Collector);
LIMNIMETRIC
RULER
Application for smartphones in Ios Language / Android / Windows for data and image register of flooding points.
It can be considered that the completion of the mapping process of flooding points was
only a first step towards the implementation of a more complete georeferenced system, for
which the adoption of an ongoing effort to improve is required by including improvements in the
system, so that it will possible in a near future to obtain more accurate data related to rainfall
and hydraulic flow.
The goal will be to evolve the system to a level in which the development of a real-time
simulation forecasting of hydrological scenarios, based on data obtained from the data network,
can be possible.
RIO DE JANEIRO CITY HALL
MUNICIPALSECRETARY OF SANITATION AND WATER RESOURCES
SMAR
WATER SANITATION AND DRAINAGE AUTHORITY - RIOÁGUAS
BOARD OF STUDIES AND PROJECTS
MANAGEMENT OF RESEARCH AND TECHNICAL SUPPORT
References
- INSTRUÇÕES TÉCNICAS PARA ELABORAÇÃO DE ESTUDOS HIDROLÓGICOS E
DIMENSIONAMENTO HIDRÁULICO DE SISTEMAS DE DRENAGEM URBANA (Aprovada
pela Portaria O/SUB – RIO-ÁGUAS “N” nº. 004/2010).
- INFORMAÇÕES NECESSÁRIAS PARA PROCEDIMENTOS DE AÇÃO NOS ESTÁGIOS DE
ALERTA DE CHUVA EMITIDOS PELO COR-RIO - FEVEREIRO/2013.
- INSTRUÇÕES TÉCNICAS PARA ELABORAÇÃO DE ESTUDOS HIDROLÓGICOS E
DIMENSIONAMENTO HIDRÁULICO DE SISTEMAS DE DRENAGEM URBANA (Aprovada
pela Portaria O/SUB – RIO-ÁGUAS “N” nº. 004/2010) - 1ª. Versão - Dezembro 2010.
- Relatório N.º 4-3-D-001271 - RIO-ÁGUAS/DEP/GPST - ESTUDO PARA IMPLANTAÇÃO DE
UM SISTEMA DE RÉGUAS LINIMÉTRICAS PARA MEDIÇÃO DE LÂMINAS D´ÁGUA NOS
PONTOS DE DRENAGEM SUPERVISIONADOS - OUTUBRO/2015.
- Relatório N.º 4-3-D- 001288 - RIO-ÁGUAS/DEP/GPST - ESTUDO PARA ELABORAÇÃO DE
APLICATIVO PARA SMARTFONES EM LINGUAGEM IOS/ANDROID PARA REGISTRO
DE DADOS E IMAGENS REFERENTES AOS BOLSÕES DE ÁGUA - MARÇO/2016.
- Relatório N.º 5-3-D-000417 - RIO-ÁGUAS/DEP/CGPM - AVALIAÇÃO DOS PONTOS DE
DRENAGEM
REPORTADOS
MAPEAMENTO
EM
PELOS
SISTEMA
ÓRGÃOS
VINCULADOS
GEORREFERENCIADO
CHUVOSOS NO ANO DE 2015 - MARÇO/2015
AO
(ARCGIS)
COR-RIO
-
E
EVENTOS