Has Rotifera richness, abundance, and biomass been underestimated in a tropical watershed basins?

Limnetica ◽  
2021 ◽  
Vol 40 (2) ◽  
pp. 295-307
Author(s):  
Mariane Amorim Rocha ◽  
Sylvia Maria Moreira Susini Ribeiro ◽  
Mauro De Melo Júnior ◽  
Márcio Borba da Silva ◽  
Pedro Augusto Mendes De Castro Melo
Keyword(s):  
Tropical Watershed

scholarly journals Initial abstraction ratio and Curve Number estimation using rainfall and runoff data from a tropical watershed

RBRH ◽  
2019 ◽  
Vol 24 ◽  
Author(s):  
Luiz Claudio Galvão do Valle Junior ◽  
Dulce Buchala Bicca Rodrigues ◽  
Paulo Tarso Sanches de Oliveira
Keyword(s):  
Conversion Factor ◽  
Poor Performance ◽  
Curve Number ◽  
Storm Events ◽  
Rainfall Runoff ◽  
Initial Abstraction ◽  
Rainfall Depth ◽  
Standard Value ◽  
Tropical Watershed ◽  
Runoff Events

ABSTRACT The Curve Number (CN) method is extensively used for predict surface runoff from storm events. However, remain some uncertainties in the method, such as in the use of an initial abstraction (λ) standard value of 0.2 and on the choice of the most suitable CN values. Here, we compute λ and CN values using rainfall and runoff data to a rural basin located in Midwestern Brazil. We used 30 observed rainfall-runoff events with rainfall depth greater than 25 mm to derive associated CN values using five statistical methods. We noted λ values ranging from 0.005 to 0.455, with a median of 0.045, suggesting the use of λ = 0.05 instead of 0.2. We found a S0.2 to S0.05 conversion factor of 2.865. We also found negative values of Nash-Sutcliffe Efficiency (to the estimated and observed runoff). Therefore, our findings indicated that the CN method was not suitable to estimate runoff in the studied basin. This poor performance suggests that the runoff mechanisms in the studied area are dominated by subsurface stormflow.

scholarly journals Evaluation of Debris Flows for Flood Plain Estimation in a Small Ungauged Tropical Watershed for Hurricane Otto

Hydrology ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 122
Author(s):  
Sebastián Fallas Salazar ◽  
Alejandra M. Rojas González
Keyword(s):  
Debris Flows ◽  
Flood Plain ◽  
Rain Gauge ◽  
Economic Losses ◽  
Clean Water ◽  
Newtonian Flows ◽  
Bias Factor ◽  
Input Source ◽  
Debris Flood ◽  
Tropical Watershed

The variability of climate, increase in population, and lack of territorial plans in Costa Rica have caused intense disasters with human and economic losses. In 2016, Hurricane Otto hit the country’s northern area, leaving substantial damages, including landslides, debris flows, and flooding. The present study evaluated different scenarios to estimate flooded areas for Newtonian (clean water), and non-Newtonian flows with volumetric sediment concentrations (Cv) of 0.3, 0.45, 0.55, and 0.65 using Hydro-Estimator (HE), rain gauge station, and the 100-year return period event. HEC–HMS modeled the rainfall products, and FLO-2D modeled the hydrographs and Cv combinations. The simulation results were evaluated with continuous statistics, contingency table, Nash Sutcliffe Efficiency, measure of fit (F), and mean absolute differences (E) in the floodplains. Flow depths, velocities, and hazard intensities were obtained in the floodplain. The debris flood was validated with field data and classified with a Cv of 0.45, presenting lower MAE and RMSE. Results indicated no significant differences in flood depths between hydrological scenarios with clean-water simulations with a difference of 8.38% in the peak flow. The flood plain generated with HE rainfall and clear-water condition presented similar results compared to the rain gauge input source. Additionally, hydraulic results with HE and Cv of 0.45 presented E and F values similar to the simulation of Cv of 0.3, demonstrating that the HE bias did not influence the determination of the floodplain depth and extent. A mean bias factor can be applied to a sub-daily temporal resolution to enhance HE rain rate quantifications and floodplain determination.

scholarly journals Composition of eroded carbon during its journey through a tropical watershed: a clue to the question whether it is source or sink of CO<sub>2</sub>

2013 ◽  
Vol 10 (11) ◽  
pp. 18175-18192
Author(s):  
C. Rumpel ◽  
V. Chaplot ◽  
P. Ciais ◽  
A. Chabbi ◽  
B. Bouahom ◽  
...  
Keyword(s):  
Organic Matter ◽  
Chemical Composition ◽  
Isotope Composition ◽  
Soil Profiles ◽  
Small Watershed ◽  
15N Isotope ◽  
Lateral Transport ◽  
Vertical Decomposition ◽  
Soil Units ◽  
Tropical Watershed

Abstract. In order to assess whether eroded carbon is a net source or sink of atmospheric CO2, characterisation of the chemical composition and residence time of eroded organic matter (EOM) at the landscape level is needed. This information is crucial to evaluate how fast EOM can be decomposed by soil microbes during its lateral transport. This study considers a continuum of scales to measure the fate of EOM during its transport, across a steep hillslope landscape of the Mekong basin, with intense erosion. Here we show that changes in the chemical composition of EOM (measured by NMR spectroscopy) and in its 13C and 15N isotope composition provide consistent evidence for EOM decomposition during the lateral transport of carbon on time scales of less than 50 yr across distances of 10 km. Between individual soil units (1 m2) to a small watershed (107 m2), the observed 28% decrease of the C/N ratio and the enrichment of 13C and 15N isotopes in EOM is of similar magnitude than the enrichment with depth in soil profiles due to soil organic matter "vertical" decomposition. Radiocarbon measurements indicated that these changes are not related to the slow transformation of soil carbon during pedogenesis, but rather to an acceleration of the SOM stabilisation process during its journey through the watershed.

Improving Urban Flood Resilience under Climate Change Scenarios in a Tropical Watershed Using Low-Impact Development Practices

2021 ◽  
Vol 26 (12) ◽  
Author(s):  
Tiago Souza Mattos ◽  
Paulo Tarso S. Oliveira ◽  
Leonardo de Souza Bruno ◽  
Nilo Dinis de Oliveira ◽  
Jose G. Vasconcelos ◽  
...  
Keyword(s):  
Climate Change ◽  
Low Impact Development ◽  
Climate Change Scenarios ◽  
Urban Flood ◽  
Tropical Watershed

Distributions of enterococci and human-specific bacteriophages of enterococci in a tropical watershed

2020 ◽  
Vol 226 ◽  
pp. 113482 ◽  
Author(s):  
Natcha Chyerochana ◽  
Akechai Kongprajug ◽  
Pornjira Somnark ◽  
Pinida Leelapanang Kamphaengthong ◽  
Skorn Mongkolsuk ◽  
...  
Keyword(s):  
Tropical Watershed ◽  
Human Specific
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