Importance of adequate appropriation of physiographic information for concentration times determination

Abstract

Concentration time is an important parameter for drainage systems design and is closely related to the physiographic characteristics of a given hydrographic basin. Information from cartographic bases or images obtained by remote sensing, which present certain scales/resolutions, are often employed for the appropriation of concentration times. The present study sought to investigate the influence that the combination of different physiographic information, in different scales, and different calculation methods can produce in concentration times’ values. The applied methodology included a concentration times appropriation methods survey, identification of methods compatible with the study area characteristics, physiographic variables appropriation from information plans at different scales and concentration times determination for different regions. The results show that there is an equivalence between Tulsa District and US Corps of Engineers methods, and that these methods produce higher concentration times estimates than those produced by the George Ribeiro method. For the study area, the maximum calculated relative error was 52%.

Physiographic analysis of the Atibaia River Basin and flood susceptibility mapping in the municipality of Campinas-SP, Brazil

“…Identifying and evaluating the potential and restrictions of basins, especially urban basins, contributes to the management of water resources, such as prediction of vulnerability to flooding, inundations, and erodibility (Villela and Mattos, 1975). Several indices were developed to determine these properties, considering as physiographic characteristics those which can be obtained from maps, aerial photographs, or satellite images (Souza et al, 2018).…”

“…The determination and analysis of physiographic factors, also applied to the AHP method, has been used by several authors at municipal or hydrographic basin scales (Lorenzon et al, 2015;Souza and Sobreira, 2017;Caldas et al, 2018;Souza et al, 2018;Cezar et al, 2019;Vajtek and Vojteková, 2019;Silva et al, 2020), especially combined with geoprocessing techniques, for assessing the impacts of continuous territorial changes and the zoning of areas susceptible to possible natural disasters.…”

Experimental determination of the time of concentration, Sapucajuba creek small watershed study

“…Initially, Mulvany in 1850, in his study, conceptualized the time of concentration as being the time necessary for the rain that falls at the most remote point of the watershed to reach the outfall, or until the entire area of the watershed contributes to the flow in the outfall (Collischonn & Dornelles, 2015;Oliveira et al, 2017;Lima and Da Paz, 2016;Lousada & Camacho, 2018;Souza, et al 2018). Later, the definition and the concept of time of concentration were perfected, according to the point of view considered.…”