In:
Proceedings of the International Association of Hydrological Sciences, Copernicus GmbH, Vol. 383 ( 2020-09-16), p. 367-374
Abstract:
Abstract. The Red River is a typical example of the Southeast Asian
rivers, which has been strongly affected by human activities. This paper
analyses the change of total suspended sediment (TSS) load of the Red River
from 1960 to 2015 in which numerous new dams in both China and Vietnam have
been constructed. A strong decrease of TSS load of the whole Red River (from
79±26×106 t yr−1 in 1960s to 6±1×106 t yr−1 in 2010s) allocated to the dam impoundments in spite of
population and deforestation increase. Base on the experimental equation
describing the relationship between TSS and total organic nitrogen (TON)
concentrations, and on the available data of TSS concentration and river
discharge, the longterm TON concentrations and fluxes were calculated for
the three tributaries and the whole Red River. The annual average of TON
concentrations spatially varied from 0.41 to 3.19 mg L−1,
averaging 0.98 mg L−1 for the whole period; the lowest was found for
the Da River where the new dams have been impounded. The highest TON
concentrations and fluxes occurred in the wet season in relationship with
the highest sediment loads and river discharges. The riverine TON fluxes
transferred to estuary significantly decreased from 141×103±38×103 t yr−1 (equivalent to 902±247 kg km−2 yr−1) in 1960s to 32×103±5×103 t yr−1
(equivalent to 207±35 kg km−2 yr−1) in 2010s. The TSS flux
decrease has driven a clear reduction of associated elements like nitrogen,
which let to hypothesis a change in biogeochemical processes in the coastal
zone.
Type of Medium:
Online Resource
ISSN:
2199-899X
DOI:
10.5194/piahs-383-367-2020
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2020
detail.hit.zdb_id:
2827925-6
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