Grupo de Pesquisa em Hidrologia e Modelagem Hidrológica em Bacias Hidrográficas
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ArcLASH
  1. Where was ArcLASH developed?

The software named ArcLASH was developed by postgraduate students and professors from Federal University of Pelotas and Federal University of Lavras, who are members of the Research Group on Hydrology and Hydrological Modeling in Watersheds.

  1. Programming language

This software was developed as a script to be used in ArcGIS. ArcLASH was fully implemented in the Python programming language by making use of the arcpy library, which consists of a set of geoprocessing procedures intended for applications in ArcGIS.

  1. Minimum computer configurations

We recommend systems that meet or exceed the following specifications in order to use ArcLASH: 2.2 GHz processor and 2 GB RAM memory. In addition, users also need a licence of ArcGIS 10.1 or higher and the Spatial Analyst extension.

  1. Scope

The hydrological model referred to as Lavras Simulation of Hydrology (LASH) was developed by researchers of the Engineering Department from Federal University of Lavras in conjunction with a researcher from the National Soil Erosion Research Laboratory (NSERL/USDA) – Purdue University, USA (Viola 2008; Beskow 2009). LASH is a long-term, distributed, semi-conceptual and deterministic hydrological model intended for representation of some hydrological processes, whose information are difficult to be acquired in ungauged watersheds, such as evapotranspiration, interception, capillary rise, soil water storage, direct surface runoff, subsurface runoff and baseflow. This hydrologic model has been successfully applied to Brazilian watersheds (Mello et al., 2008; Beskow et al., 2011a; Beskow et al., 2011b; Viola et al., 2012a, Viola et al., 2012b; Beskow et al., 2013; Viola et al., 2014a; Viola et al., 2014b). The version of LASH used for the above-mentioned studies fulfilled functions strictly associated with research, however, it is appropriate for users other than the developers and members of the Research Group. Also, LASH is not protected by copyright.

In order to increase the LASH applicability, its second version has been developed thanks to research projects conducted by the Research Group in which several alterations and enhancements have been incorporated into LASH. In this context, one of the alterations refers to the development of ArcLASH which is a module structured in the ArcGIS environment to support and automate the processing of spatial data bases required by LASH.

The objective of ArcLASH is to automate all the preparation of geographical databases (maps) required by LASH, thereby minimizing the chances of users inputting erroneous information in the databases needed for hydrological simulation and making it easier the database compilation. ArcLASH was then developed to execute a logical sequence of geoprocessing and hydrology operations seeking to reduce such errors. 

  1. ArcLASH interface and input

Once ArcLASH is installed, it can be accessed within ArcGIS by using its “ArcToolBox”, as illustrated in Figure 1.

Figura 1 – Acesso do programa ArcLASH no SIG ArcGIS

Figure 1 – Exemplification of how users can access ArcLASH in ArcGIS.

ArcLASH enables users to input maps representing regions, which might differ in size and coordinate system. The software executes all the necessary procedures to process the maps within the same region of interest and with the same coordinate system. Please, see below an illustrative example for each map that is required by ArcLASH taking into account a watershed situated in the region of Pelotas, Rio Grande do Sul State.

Figura 2 NOVA

Figure 2 – Importation of the digital elevation model (DEM) of a region and the outlet of interest into ArcLASH. In this example, the outlet refers to Cordeiro de Farias bridge, in Pelotas/Rio Grande do Sul State.

Figura 3 NOVA

Figure 3 – Importation of a soil map covering Rio Grande do Sul State into ArcLASH, as well as choice of a field from the attribute table to identify the soil classes.

Figura 4 – Entrada no ArcLASH de um mapa de usos do solo considerando grande parte do estado do Rio Grande do Sul e a definição do campo da tabela de atributos que identifica as classes de uso do solo.

Figure 4 – Importation of a land-use map covering a large area of Rio Grande do Sul State into ArcLASH, as well as selection of a field from the attribute table to identify the land-use classes.

Figura 5 – Entrada no ArcLASH de um mapa contendo as estações pluviométricas que serão empregadas na modelagem com o LASH.

Figure 5 – Importation of a map containing the rain gauges that will be considered for hydrological modeling with LASH.

Figura 6 – Entrada no ArcLASH de um mapa contendo as estações meteorológicas que serão empregadas na modelagem com o LASH.

Figure 6 – Importation of a map containing the meteorological stations that will be considered for hydrological modeling with LASH.

For additional information on input, procedures and output, users are encouraged to read the ArcLASH tutorial, which is stored in the same folder where ArcLASH is installed.

  1. Results generated by ArcLASH

     ArcLASH executes various geoprocessing and hydrology operations, thus resulting in maps and tables that are stored in two folders automatically created by the software in a path defined by the user.

6.1) Raster maps in ASCII format

Please, see below the maps in ASCII format generated by ArcLASH.Please, see below an illustrative example for each map in ASCII format that is generated by ArcLASH based on a watershed situated in the region of Pelotas, Rio Grande do Sul State:

Figura 7 – Modelo digital de elevação hidrologicamente consistente da bacia hidrográfica do Arroio Pelotas (Pelotas-RS), a montante da Ponte Cordeiro de Farias, a partir do processamento no ArcLASH e o arquivo ASCII correspondente no formato do SIG ArcGIS.

Figure 7 – Hydrologically consistent digital elevation model derived from processing in ArcLASH for the Pelotas river watershed upstream from Cordeiro de Farias bridge (Pelotas-RS), as well as the corresponding ASCII format file.

Figura 8 – Mapa de declividade da bacia hidrográfica do Arroio Pelotas (Pelotas-RS), a montante da Ponte Cordeiro de Farias, a partir do processamento no ArcLASH e o arquivo ASCII correspondente no formato do SIG ArcGIS.

Figure 8 – Slope map derived from the processing in ArcLASH for Pelotas river watershed upstream from Cordeiro de Farias bridge (Pelotas-RS), as well as the corresponding ASCII format file.

Figura 9 – Mapa de direções de fluxo da bacia hidrográfica do Arroio Pelotas (Pelotas-RS), a montante da Ponte Cordeiro de Farias, a partir do processamento no ArcLASH e o arquivo ASCII correspondente no formato do SIG ArcGIS.

Figure 9 – Flow direction map derived from the processing in ArcLASH for the Pelotas river watershed upstream from Cordeiro de Farias bridge (Pelotas-RS), as well as the corresponding ASCII format file.

Figura 10 – Mapa de acúmulos de fluxo da bacia hidrográfica do Arroio Pelotas (Pelotas-RS), a montante da Ponte Cordeiro de Farias, a partir do processamento no ArcLASH e o arquivo ASCII correspondente no formato do SIG ArcGIS.

Figure 10 – Flow accumulation map derived from the processing in ArcLASH for the Pelotas river watershed upstream from Cordeiro de Farias bridge (Pelotas-RS), as well as the corresponding ASCII format file.

Figura 11 – Mapa da rede de drenagem obtida numericamente para a bacia hidrográfica do Arroio Pelotas (Pelotas-RS), a montante da Ponte Cordeiro de Farias, a partir do processamento no ArcLASH e o arquivo ASCII correspondente no formato do SIG ArcGIS.

Figure 11 – Drainage network map numerically derived from the processing in ArcLASH for the Pelotas river watershed upstream from Cordeiro de Farias bridge (Pelotas-RS), as well as the corresponding ASCII format file.

Figura 12 – Mapa de sub-bacias hidrográficas da bacia hidrográfica do Arroio Pelotas (Pelotas-RS), a montante da Ponte Cordeiro de Farias, a partir do processamento no ArcLASH e o arquivo ASCII correspondente no formato do SIG ArcGIS.

Figure 12 – Map of subwatersheds derived from the processing in ArcLASH for the Pelotas river watershed upstream from Cordeiro de Farias bridge (Pelotas-RS), as well as the corresponding ASCII format file.

Figura 13 – Mapa de classes de solo da bacia hidrográfica do Arroio Pelotas (Pelotas-RS), a montante da Ponte Cordeiro de Farias, a partir do processamento no ArcLASH e o arquivo ASCII correspondente no formato do SIG ArcGIS.

Figure 13 – Map of soil classes derived from the processing in ArcLASH for the Pelotas river watershed upstream from Cordeiro de Farias bridge (Pelotas-RS), as well as the corresponding ASCII format file.

Figura 14 – Mapa de classes de uso do solo da bacia hidrográfica do Arroio Pelotas (Pelotas-RS), a montante da Ponte Cordeiro de Farias, a partir do processamento no ArcLASH e o arquivo ASCII correspondente no formato do SIG ArcGIS.

Figure 14 – Map of land-use classes derived from the processing in ArcLASH for the Pelotas river watershed upstream from Cordeiro de Farias bridge (Pelotas-RS), as well as the corresponding ASCII format file.

Figura 16 – Mapa ilustrando a área de influência de cada estação meteorológica dentro da bacia hidrográfica do Arroio Pelotas (Pelotas-RS), a montante da Ponte Cordeiro de Farias, a partir do processamento no ArcLASH e o arquivo ASCII correspondente no formato do SIG ArcGIS.

Figure 15 – Map illustrating the influence area of each rain gauge derived from the processing in ArcLASH for the Pelotas river watershed upstream from Cordeiro de Farias bridge (Pelotas-RS), as well as the corresponding ASCII format file.

6.2) Tables

ArcLASH also generates 3 important text files to execute the LASH model, which are related to the outlet, rain gauges and meteorological stations. These files are imported into LASH and then associated with temporal databases. By way of illustration, Figure 16 depicts a text file related to rain gauges.

Figura 17 – Arquivo de texto gerado pelo ArcLASH detalhando as informações das estações pluviométricas que serão vinculadas ao respectivo banco de dados no LASH.

Figure 16 – Text file generated by ArcLASH detailing information on the rain gauges that will be linked to the database in LASH.

7. Bibliographic References

BESKOW, S. LASH Model: a hydrological simulation tool in GIS framework. 2009. 118 f. Tese (Doutorado em Engenharia Agrícola) – Universidade Federal de Lavras, Lavras, 2009.

BESKOW, S. Mello, c. r. de; NORTON, L. D. Development, sensivity and uncertainty analysis of LASH model. Scientia Agricola, v. 68, n. 3, p. 265-274, 2011.

BESKOW, S.; mello, c. r. de; NORTON, L. D.; SILVA, A. M. Performance of a distributed semi-conceptual hydrological model under tropical watershed conditions. Catena, v. 86, p. 160-171, 2011b.

BESKOW, S.; NORTON, L. D.; MELLO, C. R. de. Hydrological prediction in a tropical watershed dominated by Oxisols using a distributed hydrological model. Water Resources Management, v. 27, p. 341-363, 2013.

Mello C. R.; Viola, M. R.; Norton, L. D.; Silva, A. M.; Weimar, F. A. Development and application of a simple hydrologic model simulation for a Brazilian headwater basin. Catena, v. 75, n. 3, p. 235-247, 2008.

VIOLA, M. R. Simulação hidrológica na região do alto rio Grande a montante do reservatório de Camargos/CEMIG. 2008. 120 f. Dissertação (Mestrado em Engenharia Agrícola) – Universidade Federal de Lavras, Lavras, 2008.

VIOLA, M. R. Simulação hidrológica na cabeceira da bacia hidrográfica do rio Grande de cenários de usos do solo e mudanças climáticas A1B. 2011. 286 p. Tese (Doutorado em Recursos Hídricos em Sistemas Agrícola) – Universidade Federal de Lavras, Lavras, 2011.

VIOLA, M. R.; MELLO, C. R. de; GIONGO, M.; BESKOW, S.; SANTOS, A. F. dos. Modelagem hidrológica em uma sub-bacia hidrográfica do baixo rio Araguaial, TO. Journal of Biotechnology and Biodiversity, v. 3, n. 3, p. 38-47, 2012.

VIOLA, M. R.; MELLO, C. R. de; BESKOW, S.; NORTON, L. D. Applicability of the LASH Model for hydrological simulation of the Grand River Basin, Brazil. Journal of Hydrologic Engineering, v. 18, n. 12, p. 1639-1652, 2013.

VIOLA, M. R.; MELLO, C. R. de; BESKOW, S.; NORTON, L. D. Impacts of land-use changes on the hydrology of the Grande river basin headwaters, Southeastern, Brazil. Water Resources Management, v. 28, p. 4537-4550, 2014a.

 VIOLA, M. R.; MELLO, C. R. de; CHOU, S. C.; YANAGI, S. N.; GOMES, J. L. Assessing climate change impacts on Upper Grande River basin hydrology, Southeast Brazil. International Journal of Climatology, 2014b.