The hydrological response of baseflow in fractured mountain areas

Abstract

Abstract. The study of baseflow in mountainous areas of basin headwaters, where the characteristics of the often fractured materials are very different to the standard issues concerning porous material applied in conventional hydrogeology, is an essential element in the characterization and quantification of water system resources. Their analysis through recession fragments provides information on the type of response of the sub-surface and subterranean systems and on the average relation between the storage and discharge of aquifers, starting from the joining of these fragments into a single curve, the Master Recession Curve (MRC). This paper presents the generation of the downward MRC over fragments selected after a preliminary analysis of the recession curves, using a hydrological model as the methodology for the identification and the characterization of quick sub-surface flows flowing through fractured materials. The hydrological calculation has identified recession fragments through surface runoff or snowmelt and those periods of intense evapotranspiration. The proposed methodology has been applied to three sub-basins belonging to a high altitude mountain basin in the Mediterranean area, with snow present every year, and their results were compared with those for the upward concatenation of the recession fragments. The results show the existence of two different responses, one quick (at the sub-surface, through the fractured material) and the other slow, with linear behaviour which takes place in periods of 10 and 17 days respectively and which is linked to the dimensions of the sub-basin. In addition, recesses belonging to the dry season have been selected in order to compare and validate the results corresponding to the study of recession fragments. The comparison, using these two methodologies, which differ in the time period selected, has allowed us to validate the results obtained for the slow flow.

Extreme values of snow-related variables in Mediterranean regions: trends and long-term forecasting in Sierra Nevada (Spain)

“…The average annual precipitation and mean, maximum and minimum average daily temperature for the reference period, 1960-2000, were obtained over the study area in Sierra Nevada, together with selected annual snow related-variables that were simulated during this period using the physical and distributed hydrological model, WiMMed (Herrero et al, 2011; http://www.ugr.es/~herrero/wimmed/), developed and calibrated in this region (Herrero et al, 2009(Herrero et al, , 2011Millares et al, 2009;Aguilar et al, 2010;Aguilar and Polo, 2011;Pimentel et al, 2014). The model includes specific spatial interpolation algorithms for the weather variables to include the abrupt topography of this area , and an energy and water balance snow model.…”

Generating reference evapotranspiration surfaces from the Hargreaves equation at watershed scale

“…Thus, a considerably high evaporative demand is present in this part of the watershed throughout the year (mean annual values of ET 0 close to 1000 mm yr −1 ). In addition, the presence of snow in the Northern area constitutes both a delayed water supply to the system as snowmelt, and an evaporation source under certain conditions (Herrero et al, 2009;Millares et al, 2009).…”

Baseflow Recession Analysis for Flood‐Prone Black Sea Watersheds in Turkey

“…Graphical separation techniques have been common and popular in baseflow separation practice. Although these techniques are, in particular, easy to implement for engineers in practice, researchers still look for developing new and sophisticated models [12][13][14][15][16].…”