Using object-based geomorphometry for hydro-geomorphological analysis in a Mediterranean research catchment

Abstract

Abstract. The aim of the paper is to apply an object-based geomorphometric procedure to define the runoff contribution areas and support a hydro-geomorphological analysis of a 3 km2 Mediterranean research catchment (southern Italy). Daily and sub-hourly discharge and electrical conductivity data were collected and recorded during a 3-year monitoring activity. Hydro-chemograph analyses carried out on these data revealed a strong seasonal hydrological response in the catchment that differed from the stormflow events that occur in the wet periods and in dry periods. This analysis enabled us to define the hydro-chemograph signatures related to increasing flood magnitude, which progressively involves various runoff components (baseflow, subsurface flow and surficial flow) and an increasing contributing area to discharge. Field surveys and water table/discharge measurements carried out during a selected storm event enabled us to identify and map specific runoff source areas with homogeneous geomorphological units previously defined as hydro-geomorphotypes (spring points, diffuse seepage along the main channel, seepage along the riparian corridors, diffuse outflow from hillslope taluses and concentrate sapping from colluvial hollows). Following the procedures previously proposed and used by authors for object-based geomorphological mapping, a hydro-geomorphologically oriented segmentation and classification was performed with the eCognition (Trimble, Inc.) package. The best agreement with the expert-based geomorphological mapping was obtained with weighted plan curvature at different-sized windows. By combining the hydro-chemical analysis and object-based hydro-geomorphotype map, the variability of the contribution areas was graphically modeled for the selected event, which occurred during the wet season, by using the log values of flow accumulation that better fit the contribution areas. The results allow us to identify the runoff component on hydro-chemographs for each time step and calculate a specific discharge contribution from each hydro-geomorphotype. This kind of approach could be useful when applied to similar, rainfall-dominated, forested and no-karst catchments in the Mediterranean eco-region.

An illustrated introduction to general geomorphometry

“…Slope and aspect have been well known in geosciences for many decades, and so there is no need to specify their fields of application. Curvatures are systematically used in geomorphic studies to describe, analyse and model landforms and their evolution (Burian et al, 2015; Elmahdy and Mohamed, 2013; Evans, 1980; Guida et al, 2016; Melis et al, 2014; Mitusov et al, 2013, 2014; Prasicek et al, 2014; Temovski and Milevski, 2015). In soil science and ecology, curvatures are regularly applied to study relationships in the topography–soil–vegetation system and to perform predictive soil and vegetation mapping (Behrens et al, 2010; Florinsky et al, 2002; Moore et al, 1993; Omelko et al, 2012; Sharaya and Shary, 2011; Shary and Pinskii, 2013; Shary and Smirnov, 2013; Shary et al, 2016; Stumpf et al, 2017).…”

Worldwide Research on Geoparks through Bibliometric Analysis

“…Another emerging line is Cluster 8 (brown), 'Geo-tourism in Karst System'. This type of relief formed by the chemical precipitation of carbonate rocks has led to investigations of the karst environment; e.g., its hydrological and hydrogeological characteristics have been an object of study in the Cilento, Vallo di Diano, and the Alburni geopark of Italy [199][200][201][202][203][204][205][206][207]. Karst systems are vulnerable to contamination, constitute a geological element with significant geo-tourism value, and can contribute to the environmental awareness of this type of geo-resource [223].…”

“…The members of this cluster highlight how geo-tourism promotes conservation and geo-education in karst areas. The authors of this research area have carried out hydro-geomorphological studies and hydro-chemical monitoring activities in Southern Italy in Cilento, Vallo di Diano, and the Alburni UNESCO Global Geopark [199][200][201][202][203][204][205][206][207]. Studies have been done on the 'Middle Bussento Karst System', the second-longest karstic system in Italy [208], and on geo-sites and geo-tourism in Southern Italy [209,210].…”

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“…Математическое моделирование гидрологического режима подразумевает анализ ЦМР и морфометрических моделей, почвенных, литологических и метеорологических данных, и позволяет моделировать процессы выпадения осадков, поверхностного стока, испарения, инфильтрации и др. [Guida et al, 2016;Wiekenkamp et al, 2016;Peckham et al, 2017]. Для прогноза грунтовых вод в аридных регионах неплохие результаты дает машинное обучение (алгоритмы случайного леса и максимальной энтропии) с использованием в обучающей выборке морфометрических величин [Rahmati et al, 2016].…”