Developing a Community BasedEarly Warning Systemin Vargas State, Venezuela
Lelys Bravo de Guenni1, Rafael Hernández 2, Isabel Llatas1 and Abraham Salcedo2
1Universidad Simón Bolívar, Caracas, Venezuela2Universidad Central de Venezuela, Caracas, Venezuela.
Outline
The problem and the locationAdaptation and Mitigation Measures to Hidrometeorological extremesComponents of the Early Warning SystemExperiences with the CommunityFurther research
CARACASCARACASCERRO EL AVILA
ODIF IED FROM IKONO S
PROYECTO CARACAS
Massive Debris Flows – Vargas, December 1999
Deposit of sediments and rocks from debris flows, December 1999
Mass flows
Cuenca alta San José de Galipan
Cuenca alta Camuri Chico
Cuenca media Qda. TacaguaCuenca baja Río Cerro Grande
Cuenca media Qda. Alcantarilla
Study Area: 15,000 inhabitants, located 45 minaway from Caracas
Naiguatá CamuríGrande
Event of 2005
Camurí Grande
Extreme events in the past
Source: Andressen y Pulwarty, 2003
Years with very wet Nov-Feb periods: 1951, 1976, 1986, 1992, 2000, 2005.
Table 2. Registered rainfall amounts during the wet years Year Location Amount (mm) Date 1950-1951 Maiquetia 193 16/02/1951 1975-1976 Los Caracas 100.6 17/02/1976 1985-1986 Macuto
Los Caracas Los Caracas Maiquetía-Aerop.
130.21 106.8 159.0 118.7
04/12/1985 01/11/1985 07/12/1985 04/12/1985
1991-1992 Macuto Los Caracas Maiquetía-Aerop.
152.95 157.0 98.7
26/11/1991 19/11/1991 24/11/1991
1999-2000 Maiquetía-Aerop. 410.4 15/12/1999 2004-2005 Puerto Cruz
La Guitarrita Los Caracas Los Caracas
130.9 103.6 249.5 162.6
09/02/2005 07/02/2005 08/01/2005 08/02/2005
Most events occurred during November-February
Adaptation and Mitigationmeasures to floods and debrisflows
Structural measures- Erosion control- Bed-flow stabilization- Retention and storage of sediments- Flow control channels- Improving Infrastructure
Non structural measures- Monitoring hydrometeorological variables including
sediments- Risk mapping- Land use regulations- Early warning systems- Contingency planning- Population awareness program- Insurance cover- Strengthening institutions governance
Open Dams (slotted):
a) Reinforced concrete in Qda. Guanape
b) Simple concrete in Qda. Curucuti
c) Gavions dam in El Cojo
a) b)
c)
Structural MeasuresCivil works for retention and storage of sediments
d) Gavions open dam (window type) in Camuri Chico.
f) Gavions closed dam in Macutoe) Slotted open dam
(steel tubular) inTacagua
g) Open dam (slotted), reinforced concrete in San
Julián
H = 11 mH = 11 m
Dams in SeriesQUEBRADA PIEDRA AZUL
Dam NDam N°°2 (h= 5 m) 2 (h= 5 m)
Dam NDam N°°1 (h= 5 m)1 (h= 5 m)
Dam NDam N°°3 (h= 4 m)3 (h= 4 m)
Non structural measures: Early WarningSystems (EWS)
EWS
MONITORING: Identify critical
levels
RISK ASSESSMENT:Risk components
analysis
COMUNICATION:Liason among
the community andreponse institutions
PREPARATION:Capacity building,Acting protocols
Maskrey (1997)
Community based early warning system: Example of Camurí Grande and NaiguatáBasins
For each community the following tasks are developed: Evaluation of existing hazards General information about mitigation measuresEstablishing a local risk task force Developing a local risk and emergency plan To define the role of the communityCommunal early warning system tools (portable radios, alarms,
communal rain and water level gages)Promotion activities (workshops, posters, fliers, broadcasting
etc.)Simulations (evacuation drill)
CommunalCommunal RainRain GagesGages
Container
Funnel
External Cover
CommunalCommunal RainRain GageGage
PVC Pipe 4”
Plastic Funnel
Upper Lid
Soda PlasticBottle 2 litters
Lower Lid
Community based hazard map: Camurí Grande
Community based hazard map: Naiguatá
Workshops with the Communities: Six workshops during January-June 2010
Further work
Hydrological modeling of floods and sediments in real timeDetermination of the limiting rainfall thresholds to be used by the communities for alert purposesDeveloping indicators to measure the EWS effectiveness
THANK YOU!!!!
Photos: courtesy of Prof. Arlenys Brito