Estimation of soil water content in watershed using artificial neural networks |
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Authors: | Marquis Henrique Campos de Oliveira Nilza Maria dos Reis Castro Olavo Correa Pedrollo |
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Affiliation: | Instituto de Pesquisas Hidráulicas, Universidade Federal do Rio Grande do Sul. Avenida Bento Gon?alves, Porto Alegre, Brasil |
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Abstract: | Soil water content (SWC) is an important factor in transfer processes between soil and air, contributing to water and energy balances, and quantifying it remains a challenge. This study uses artificial neural networks (ANNs) to analyse spatial and temporal variation of SWC in a Brazilian watershed, based on climate information, soil physical properties and topographic variables. Thirty eight input variables were tested in 200 models. The outputs were compared with 650 gravimetric moisture measurements collected at 26 points (25 field studies). The results show that it is possible to estimate SWC efficiently (Nash-Sutcliffe statistic, NS = 0.77) using topographic data, soil physical properties and rainfall. If only climate information is considered, modelling is less efficient (NS = 0.28). Using many variables does not necessarily improve performance. Alternatively, SWC can be estimated by simplified models using rainfall and topographic maps information, although the performance is less good (NS = 0.65). |
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Keywords: | gravimetric moisture spatial and temporal distribution physical soil parameters artificial neural networks |
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