Tropical river suspended sediment and solute dynamics in storms during an extreme drought

Water Resources Research
By: , and 

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Abstract

Droughts, which can strongly affect both hydrologic and biogeochemical systems, are projected to become more prevalent in the tropics in the future. We assessed the effects of an extreme drought during 2015 on stream water composition in the Luquillo Mountains of Puerto Rico. We demonstrated that drought base flow in the months leading up to the study was sourced from trade-wind orographic rainfall, suggesting a resistance to the effects of an otherwise extreme drought. In two catchments (Mameyes and Icacos), we sampled a series of four rewetting events that partially alleviated the drought. We collected and analyzed dissolved constituents (major cations and anions, organic carbon, and nitrogen) and suspended sediment (inorganic and organic matter (particulate organic carbon and particulate nitrogen)). The rivers appeared to be resistant to extreme drought, recovering quickly upon rewetting, as (1) the concentration-discharge (C-Q) relationships deviated little from the long-term patterns; (2) “new water” dominated streamflow during the latter events; (3) suspended sediment sources had accumulated in the channel during the drought flushed out during the initial events; and (4) the severity of the drought, as measured by the US drought monitor, was reduced dramatically after the rewetting events. Through this interdisciplinary study, we were able to investigate the impact of extreme drought through rewetting events on the river biogeochemistry.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Tropical river suspended sediment and solute dynamics in storms during an extreme drought
Series title Water Resources Research
DOI 10.1002/2016WR019737
Volume 53
Issue 5
Year Published 2017
Language English
Publisher AGU
Contributing office(s) New England Water Science Center
Description 18 p.
First page 3695
Last page 3712
Other Geospatial Puerto Rico