Stormflow generation in a small rainforest catchment in the Luquillo Experimental Forest, Puerto Rico

Abstract

Abstract:Various complementary techniques were used to investigate the stormflow generating processes in a small headwater catchment in northeastern Puerto Rico. Over 100 samples were taken of soil matrix water, macropore flow, streamflow and precipitation, mainly during two storms of contrasting magnitude, for the analysis of calcium, magnesium, silicon, potassium, sodium and chloride. These were combined with hydrometric information on streamflow, return flow, precipitation, throughfall and soil moisture to distinguish water following different flow paths. Geo-electric sounding was used to survey the subsurface structure of the catchment, revealing a weathering front that coincided with the elevation of the stream channel instead of running parallel to surface topography. The hydrometric data were used in combination with soil physical data, a one-dimensional soil water model (VAMPS) and a three-component chemical mass-balance mixing model to describe the stormflow response of the catchment. It is inferred that most stormflow travelled through macropores in the top 20 cm of the soil profile. During a large event, saturation overland flow also accounted for a considerable portion of the stormflow, although it was not possible to quantify the associated volume fully. Although the mass-balance mixing model approach gave valuable information about the various flow paths within the catchment, it was not possible to distill the full picture from the model alone; additional hydrometric and soil physical evidence was needed to aid in the interpretation of the model results.

The influence of critical zone processes on the Mg isotope budget in a tropical, highly weathered andesitic catchment

“…As was discussed in the previous section, the δ 26 Mg of baseflow reflects the input of sources deeper than any of our sampled pore water, likely flow through bedrock fractures or at the bedrock-regolith interface. Nonetheless, pore water may influence the  26 Mg signature of the stream during other stages of storm events, as has been found from water composition mixing models and hydrometric studies (Schellekens et al, 2004). The  26 Mg signature of this contribution would depend on the depth of the pathways followed by water before reaching the stream, as indicated by our data along the topographic profile, which show differing  26 Mg in pore water over a relatively short distance (Fig.…”

“…Liu et al, 2014;Pogge von Strandmann et al, 2012;Teng et al, 2010) and by the uptake by vegetation (e.g. Black et al, 2008;Bolou-Bi et al, 2012;Bolou-Bi et al, 2010;Tipper et al, 2010;Tipper et al, 2012b), thus making it a promising tracer of both the geochemical and environments, leading water to flow laterally along high-permeability, near-surface flowpaths or via saturation-excess overland flow during intense rain events (Elsenbeer, 2001;Schellekens et al, 2004;Goller et al, 2005;Bonell, 2005;Kurtz et al, 2011). Finally, recent studies in the Caribbean island of Guadeloupe have found that atmospheric inputs can have a strong influence on the …”

The impact of forest regeneration on streamflow in 12 mesoscale humid tropical catchments

“…The geology is dominated by the volcanic Cordillera Central, with a few major outcrops of plutonic rock (mostly granodiorite), and karstic limestones towards the far north and south (Olcott, 1999). Soils developed in the volcanic substrates are largely clayey Ultisols with a rapidly diminishing saturated hydraulic conductivity (K s ) with depth (Schellekens et al, 2004) whereas the granodiorites produce less clayey Ultisols with a less pronounced K s profile (Kurtz et al, 2011). Islandwide mean precipitation (P ) is ∼ 1700 mm yr −1 (Daly et al, 1994(Daly et al, , 2003.…”

A Unified Assessment of Hydrologic and Biogeochemical Responses in Research Watersheds in Eastern Puerto Rico Using Runoff–Concentration Relations

“…Both saturation overland flow and infiltration-excess overland flow (surface wash) have been observed in the Luquillo Mountains, but their relative importance has not been assessed. Saturation overland flow occurs along channels and in flow path convergence zones (Schellekens et al 2004). On hillslopes, surface wash appears to be 1-3 % of total rainfall input and is increased by earthworm presence (Larsen et al 1999.…”