Quantification of runoff generation from a combined glacier and <i>páramo</i> catchment within an Ecological Reserve in the Ecuadorian highlands

Abstract

Abstract. 10Hydrological processes in combined glacier and páramo catchments are vitally important to serve the water needs of communities in the surrounding areas. Previous studies have shown that the melting of glaciers contributes to runoff generation and that the páramo ecosystem acts as a natural sponge, which plays an important role in regulating the runoff during the dryseason. However, not all runoff processes are well-understood in the Andean region due to the high spatial variability of precipitation, young volcanic ash soil properties, soil moisture dynamics and other local factors such as vegetation interception 15 and high radiation that might influence the hydrological behaviour. In addition, there is a lack of evidence of the origin and quantification of the contribution of runoff components in the páramo ecosystem. This study focuses on data collection and experimental investigations in a small catchment (15.2 km 2 ) within an ecological reserve in the Ecuadorian Andean region. The approach consists of the identification of suitable environmental tracers and hydrochemical features to identify the various runoff sources in order to determine their respective contribution during dry and wet conditions. The results show the great 20 importance of the páramo on the contribution to total runoff during baseflow and rainfall conditions.

A concerted research effort to advance the hydrological understanding of tropical páramos

“…Time‐domain water stable isotopes have been used to determine the isotopic composition of high mountain lakes in Central American páramos (Esquivel‐Hernández et al, 2018), to estimate mean transit times (Mosquera et al, 2016; Muñoz‐Villers & McDonnell, 2012; Roa‐García & Weiler, 2010) and quantify stream water ages (53–264 days) (Mosquera, Segura, et al, 2016). Most of these studies aimed to assess the evolution of hydrological processes under different hydrometeorological conditions and quantify runoff generation (Minaya, Camacho Suarez, Wenninger, & Mynett, 2016),…”

“…In such emerging research, field‐experimental based studies started assessing previously ignored variables such as precipitation structure (Orellana‐Alvear, Célleri, Rollenbeck, & Bendix, 2017; Padrón, Wilcox, Crespo, & Célleri, 2015) and clarifying less known processes such as interception (Ochoa‐Sánchez, Crespo, & Célleri, 2018), evapotranspiration (Carrillo‐Rojas, Silva, Rollenbeck, Célleri, & Bendix, 2019; Córdova, Carrillo‐Rojas, Crespo, Wilcox, & Célleri, 2015; Ramón‐Reinozo, Ballari, Cabrera, Crespo, & Carrillo‐Rojas, 2019), and carbon and nutrient concentrations in soil and vegetation (Minaya, Corzo, van der Kwast, & Mynett, 2016; Peña‐Quemba, Rubiano‐Sanabria, & Riveros‐Iregui, 2016; Pesántez, Mosquera, Crespo, Breuer, & Windhorst, 2018; Riveros‐Iregui et al, 2018). For example, the use of conservative and bio‐reactive tracers enlightened hydrological process understanding and allowed tracking and quantifying fluxes, storage and mixing, and assisted in defining the spatial–temporal dynamics of runoff sources and flow pathways (Correa et al, 2017; Esquivel‐Hernández et al, 2018; Minaya, Camacho Suarez, Wenninger, & Mynett, 2016; Mosquera et al, 2016; Riveros‐Iregui et al, 2018). Hydrologic model applications reproduced more accurately the observed streamflows, year‐round and in drought and flood conditions (Avilés, Célleri, Paredes, & Solera, 2015; Avilés, Célleri, Solera, & Paredes, 2016; Mora, Campozano, Cisneros, Wyseure, & Willems, 2014; Muñoz, Orellana‐Alvear, Willems, & Célleri, 2018).…”

Delineation of water flow paths in a tropical Andean headwater catchment with deep soils and permeable bedrock

“…The LMWL slope and intercept can show if evaporation plays a major role in the hydrology of surface water bodies (Brooks et al, 2012;Landwehr & Coplen, 2004). In tropical regions, the isotopic composition of precipitation, surface, and subsurface waters has been used to delineate water flow paths in headwater catchments (Crespo et al, 2011;Minaya et al, 2016;Mosquera, Célleri, et al, 2016;Muñoz-Villers et al, 2016), to quantify water storage (Lazo et al, 2019), and develop conceptual models of catchment hydrological behaviour (Mosquera, Crespo, et al, 2020). Notably, Mosquera, Célleri, et al (2016) highlighted the value of water stable isotopes to understand hydrological processes of tropical Andean catchments in relatively short time periods (1-2 years), making these tracers a particularly powerful tool to fill key hydrological knowledge gaps in remote regions where monitoring is scarce.…”

“…There exist only few tracer studies in tropical Andean catchments with Holocene volcanic activity, where deep volcanic ash soils are abundant (Hall et al, 2017;Tonneijck et al, 2008). For example, Minaya et al (2016) studied the role of glacier melting in runoff generation. Nevertheless, process-based understanding of catchment hydrology in these hydrological systems is still missing (Vanacker et al, 2018).…”