WebLASH: uma plataforma web para o modelo hidrológico LASH

Abstract

Hydrological modeling in watersheds from the use of computational tools has gained space, mainly with the aim of improving the user-model interaction, as well as the exploration of results. Among the available hydrological models, the Lavras Simulation of Hydrology (LASH) can be highlighted, which is a simplified model, which requires few parameters, idealized for a reality of data scarcity, typical of Brazilian watersheds and which has been used with satisfactory performance. The purpose of LASH is to model watersheds based on the water balance, considering the storage of water in the soil and its influence on evapotranspiration and on the generation of surface, subsurface and base runoff. LASH has versions in programming languages of different typology, e.g. compiled in C++ and in Delphi, and interpreted in MATLAB® and R, proving the possibility of model versioning. The latest versions have sought to answer the following question: why not continue using LASH in spreadsheet versions or in compiled languages? The answer to this question contemplates the objective for which this study is proposed: the implementation of the model in a web environment, aiming to encourage the use of LASH by professionals in the area, mainly in consulting, where there is still little access to models in this tool. In addition, other demands can be met, such as education and assistance to public agencies, mainly in the management of water resources. In this sense, the main contribution of this study was the construction of LASH on a web platform from libraries of the R programming language so that users without programming knowledge can carry out hydrological modeling from a semi conceptual hydrological model. In addition to the web version (WebLASH), two other support versions, devised from WebLASH, were also implemented: an executable (E LASH) and a set of functions for R (F-LASH). The main difference of WebLASH for the previous versions and the two complementary versions, is that the only option of the spatial distribution of the modeling is the concentrated one for the hydrographic basin, while in the E-LASH and in the F-LASH they also contemplate the option of modeling semi-distributed by sub-basins. Complementary versions enhance the use of WebLASH by users who want to use the model via R, to understand the equation of hydrological processes, for example, and/or who need to use its semi-distributed version. Among the results achieved in this study, the following stand out: i) the simplifications and methodological improvements carried out in the development of WebLASH proved to be efficient; ii) still in its initial version, WebLASH has great potential to be applied in the consulting area and as a teaching tool; and iii) E-LASH and F-LASH tend to expand, in terms of methodology, the modeling that can be performed from WebLASH.