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Riverine dissolved organic carbon in Rukarara River Watershed, Rwanda

Rizinjirabake, Fabien LU ; Abdi, Abdulhakim M. LU ; Tenenbaum, David E. LU and Pilesjö, Petter LU (2018) In Science of the Total Environment 643. p.793-806
Abstract

Dissolved organic carbon (DOC) loading is rarely estimated in tropical watersheds. This study quantifies DOC loading in the Rukarara River Watershed (RRW), a Rwandan tropical forest and agricultural watershed, and evaluates its relationship with hydrological factors, land use and land cover (LULC), and topography to better understand the impact of stream DOC export on watershed carbon budgets. The annual average load for the study period was 977.80 kg C, which represents approximately 8.44% of the net primary productivity of the watershed. The mean daily exports were 0.37, 0.14, 0.075 and 0.32 kg C/m2 in streams located in natural forest, tea plantation, small farming areas, and at the outlet of the river, respectively. LULC... (More)

Dissolved organic carbon (DOC) loading is rarely estimated in tropical watersheds. This study quantifies DOC loading in the Rukarara River Watershed (RRW), a Rwandan tropical forest and agricultural watershed, and evaluates its relationship with hydrological factors, land use and land cover (LULC), and topography to better understand the impact of stream DOC export on watershed carbon budgets. The annual average load for the study period was 977.80 kg C, which represents approximately 8.44% of the net primary productivity of the watershed. The mean daily exports were 0.37, 0.14, 0.075 and 0.32 kg C/m2 in streams located in natural forest, tea plantation, small farming areas, and at the outlet of the river, respectively. LULC is a factor that influences DOC loading. The quick flow was the main source of stream DOC at all study sites. Stream DOC increases with increasing water flow, indicating a positive relationship. Thus, the expectation is that a change in land cover and/or rainfall will result in a change of stream DOC dynamics within the watershed. Topography was also found to influence the dynamics of stream DOC through its effect on overland flow in terms of drainage area and total length of flow paths. Tea plantations were located in areas of high drainage density and projected increase of rainfall in the region, as a consequence of climate change, could increase stream DOC content and affect stream water quality, biodiversity, balance between autotrophy and heterotrophy, and bioavailability of toxic compounds within the RRW.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Dissolved organic carbon, Land use and land cover, Rwanda, Stream water, Watershed
in
Science of the Total Environment
volume
643
pages
14 pages
publisher
Elsevier
external identifiers
  • scopus:85049052579
ISSN
0048-9697
DOI
10.1016/j.scitotenv.2018.06.194
language
English
LU publication?
yes
id
2246cf13-0386-44cf-874d-bdf8eba0fe2e
date added to LUP
2018-07-04 08:38:06
date last changed
2019-02-20 11:21:25
@article{2246cf13-0386-44cf-874d-bdf8eba0fe2e,
  abstract     = {<p>Dissolved organic carbon (DOC) loading is rarely estimated in tropical watersheds. This study quantifies DOC loading in the Rukarara River Watershed (RRW), a Rwandan tropical forest and agricultural watershed, and evaluates its relationship with hydrological factors, land use and land cover (LULC), and topography to better understand the impact of stream DOC export on watershed carbon budgets. The annual average load for the study period was 977.80 kg C, which represents approximately 8.44% of the net primary productivity of the watershed. The mean daily exports were 0.37, 0.14, 0.075 and 0.32 kg C/m<sup>2</sup> in streams located in natural forest, tea plantation, small farming areas, and at the outlet of the river, respectively. LULC is a factor that influences DOC loading. The quick flow was the main source of stream DOC at all study sites. Stream DOC increases with increasing water flow, indicating a positive relationship. Thus, the expectation is that a change in land cover and/or rainfall will result in a change of stream DOC dynamics within the watershed. Topography was also found to influence the dynamics of stream DOC through its effect on overland flow in terms of drainage area and total length of flow paths. Tea plantations were located in areas of high drainage density and projected increase of rainfall in the region, as a consequence of climate change, could increase stream DOC content and affect stream water quality, biodiversity, balance between autotrophy and heterotrophy, and bioavailability of toxic compounds within the RRW.</p>},
  author       = {Rizinjirabake, Fabien and Abdi, Abdulhakim M. and Tenenbaum, David E. and Pilesjö, Petter},
  issn         = {0048-9697},
  keyword      = {Dissolved organic carbon,Land use and land cover,Rwanda,Stream water,Watershed},
  language     = {eng},
  month        = {12},
  pages        = {793--806},
  publisher    = {Elsevier},
  series       = {Science of the Total Environment},
  title        = {Riverine dissolved organic carbon in Rukarara River Watershed, Rwanda},
  url          = {http://dx.doi.org/10.1016/j.scitotenv.2018.06.194},
  volume       = {643},
  year         = {2018},
}