Assessing the capacity of large-scale hydrologic-hydrodynamic models for mapping flood hazard in southern Brazil

Maria Eduarda Pereira Alves

Instituto de Pesquisas Hidráulicas, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brasil

Fernando Mainardi Fan

Instituto de Pesquisas Hidráulicas, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brasil

Rodrigo Cauduro Dias de Paiva

Instituto de Pesquisas Hidráulicas, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brasil

Vinícius Alencar Siqueira

Instituto de Pesquisas Hidráulicas, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brasil

Ayan Santos Fleischmann

Instituto de Desenvolvimento Sustentável Mamirauá, Tefé, AM, Brasil

João Paulo Brêda

Instituto de Pesquisas Hidráulicas, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brasil

Leonardo Laipelt

Instituto de Pesquisas Hidráulicas, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brasil

Alexandre Abdalla Araújo

Agência Nacional de Águas e Saneamento Básico, Brasília, DF, Brasil

Editor-in-Chief: Adilson Pinheiro

Associated Editor: Iran Eduardo Lima Neto

Flood of 1983	Model	H
Uruguaiana	MGB REG	0.482
Uruguaiana	MGB AS	0.465

RP	Model	H	RP	Model	H
3 years	MGB REG	0.689	25 years	MGB REG	0.812
3 years	MGB AS	0.920	25 years	MGB AS	0.947
5 years	MGB REG	0.715	50 years	MGB REG	0.832
5 years	MGB AS	0.937	50 years	MGB AS	0.937
10 years	MGB REG	0.771	100 years	MGB REG	0.860
10 years	MGB AS	0.928	100 years	MGB AS	0.941

RP	Model	H	RP	Model	H
3 years	MGB REG	0.723	25 years	MGB REG	0.784
3 years	MGB AS	0.635	25 years	MGB AS	0.619
5 years	MGB REG	0.733	50 years	MGB REG	0.833
5 years	MGB AS	0.633	50 years	MGB AS	0.608
10 years	MGB REG	0.753	100 years	MGB REG	0.868
10 years	MGB AS	0.663	100 years	MGB AS	0.607

Methodology	Strengths	Weaknesses
Local benchmark - CPRM	-Ease application.	-It does not consider the water surface slope.
	-Depends only on DEM and observed water level data.	-The conservation of flood volume is not ensured.
		-The flood hazard map is limited to urban areas.
Regional MGB	-Conservative mass balance approach;	-Coarser DEM resolution compared to that used in the CPRM study.
	-Hydrological-hydrodynamic simulation, with more variables represented.	- Regional MGB model calibration is necessary.
	-Model is calibrated for the area of interest.	-Limited representation of floodplain flows (only storage).
	- The flood hazard map covers a larger area, with a relatively lower local surveying effort.
Continental MGB	-Flood hazard maps are easily extracted since the model is already prepared and calibrated.	-Coarser DEM resolution than that of the Regional MGB model.
	-Conservative mass balance approach;	-Coarser model spatial discretization.
	-Hydrological-hydrodynamic simulation, with more variables represented.	-Less detailed model calibration (water balance and river geometry parameters).
	- The flood hazard map covers a larger area, with a lower local surveying effort.	-Larger uncertainty in meteorological forcing data (e.g., satellite, reanalysis).

Brasil