کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
8912331 | 1639333 | 2018 | 42 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Changes in streamflow contributions with increasing spatial scale in Thukela basin, South Africa
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
ژئوشیمی و پترولوژی
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چکیده انگلیسی
Sustainable management of river basins requires precise understanding of the origin and variability of water fluxes. Water samples were collected in Thukela Basin (30,000â¯km2), South Africa, over the 2012 rainy season, from fifteen 1â¯m2 runoff microplots (for OF), a 5-m deep piezometer (SW) and 20-m deep borehole (GW), in the basin headwater and nested catchment outlets (microcatchment, 0.23â¯km2; subcatchment, 1.20â¯km2; catchment, 9.75â¯km2; sub-basin, 253â¯km2). The water samples were analysed for Sodium (Na) and Silica (Si) concentrations using an inductively coupled-plasma emission spectrophotometry. End Member Mixing Analysis (EMMA), with Na and Si as tracers, was then used to quantify the water compartment contributions to river flow. The results showed a general decrease of unit-area runoff in downslope direction from 5.7 to 1.2â¯Lâ¯mâ2 dayâ1â¯at microplot and microcatchment level, respectively, to 1.4â¯Lâ¯mâ2 dayâ1â¯at the basin outlet. OF contributions averaged 61% at microcatchment, 79% at subcatchment, 40% at catchment, 78% at sub-basin and 67% at the basin outlet, which corresponded to 0.82, 0.26, 5â¯Ãâ¯10â5, 2â¯Ãâ¯10â3 and 9â¯Ãâ¯10â5â¯Lâ¯mâ2 dayâ1, respectively. The respective SW contributions were 39% (0.38â¯Lâ¯mâ2 dayâ1), 18% (0.10â¯Lâ¯mâ2 dayâ1), 49% (5â¯Ãâ¯10â5â¯Lâ¯mâ2 dayâ1), 15% (4â¯Ãâ¯10â4â¯Lâ¯mâ2 dayâ1) and 33% (5â¯Ãâ¯10â5â¯Lâ¯mâ2 dayâ1). GW contributions were much lower at all spatial scales, but showed a general increase with increasing contributing surface area from microcatchment to sub-basin outlet followed by a decrease to the basin outlet. The end-member contributions showed large spatial variations, hence longer-term research integrating more observation points is recommended to generate adequate data for development of prediction models for this important river basin. More research linking carbon, nutrient and pollutant fluxes to water dynamics is also recommended.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Physics and Chemistry of the Earth, Parts A/B/C - Volume 105, June 2018, Pages 32-43
Journal: Physics and Chemistry of the Earth, Parts A/B/C - Volume 105, June 2018, Pages 32-43
نویسندگان
Macdex Mutema, Vincent Chaplot,