Spatial Variations in the Stable Isotopic Compositions of Surface and Groundwaters across Central Sri Lanka

Abstract

Stable Isotopic Compositions across Central Sri Lanka the baseflow from a streamflow hydrograph (Jones et al. 2006, Tweed et al. 2016), estimating the influx of groundwater into lakes (Sacks et al. 2014, Ala-aho et al. 2015), and identifying the origin of groundwater and flow processes (Kamtchueng et al. 2015). Rainfall in Sri Lanka is controlled by the tropical monsoon system. Monsoon rains are closely related to the regional livelihood and social water use, making stable water supply and flood/drought management a necessity. Accordingly, various studies have used stable isotopes to investigate the meteorological and hydrological settings in Sri Lanka. Dharmasiri & Athuluwage (1991) reported the monthly stable isotopic variations in rainwater at seven sites to constrain the isotopic input into groundwater. Jayasena et al. (2008) characterized the isotopic compositions of rainwater in the dry and intermediate

Global Isotope Hydrogeology―Review

“…Recharge elevations have been estimated with groundwater δ 18 O data in dozens of areas around the globe (Table ; e.g., Gonfiantini et al, ; Carreira et al, ; Marques et al, ; N'da et al, ; Leketa et al, ; Tsuchihara et al, ). Studies are concentrated, unsurprisingly, in areas of high topographic relief, including the northern China, Morocco, Ethiopia, Europe, and mountain ranges spanning the Americas (Figure ).…”

Tracing Water Sources and Fluxes in a Dynamic Tropical Environment: From Observations to Modeling

“…The distinct isotopic pulses or input functions provided by rainfall in the tropics are commonly damped or modified by different ecological and hydrogeological processes across the landscape. Connectivity between groundwater and surface water compartments have been widely studied in humid tropical watersheds (Gordon et al, 2015;Lagomasino et al, 2015;Batista et al, 2018;Oiro et al, 2018;Villegas et al, 2018;Welsh et al, 2018;Tsuchihara et al, 2019); however, large scale or regional approaches are uncommon across tropical biomes. Figure 9 shows locations of groundwater (N 1,156) and surface water (N 603) sampling efforts across Costa Rica (2016-2019).…”