Dissolved load and tentative solute budgets of some Norfolk catchments
1973; Elsevier BV; Volume: 18; Issue: 3-4 Linguagem: Inglês
10.1016/0022-1694(73)90048-6
ISSN1879-2707
Autores Tópico(s)Soil and Water Nutrient Dynamics
ResumoWeekly water samples were collected during 1970 from the rivers Yare, Tud and Wensum in Norfolk. The relationships between discharge and the variations in the dissolved load of sodium, potassium, calcium, magnesium, silicon, chloride, bicarbonate, nitrate, phosphate and sulphate were examined by regression analysis. The correlation coefficients were all highly significant and the slopes of the regression equations in most cases approximated to +1. The slope coefficients for nitrate and sulphate were greater than +1, as their concentration increased with discharge. Most of the phosphate in the Yare and Wensum was derived from sewage effluent, which was diluted by high flows. The most effective discharges for transporting all constituents were those of winter baseflow. Only 20% of the load was removed from the catchments between May and October. Tentative solute budgets showed that rainfall was a significant input for potassium, magnesium, sodium, chloride and sulphate. For chloride in the Tud this amounted to 55%. Sewage contributed less than 15% of the input of the constituents except phosphorus. It was unlikely that more than 10% of the fertilizer nitrogen was lost by leaching to the rivers. Calcium was derived from the solution of carbonate and sulphate minerals. The calcium carbonate erosion rate was 58.0 Mg/km2 for the Yare and 39.2 Mg/km2 for the Tud. The silicon erosion rate, correct for depletion by diatoms, was 1.1 Mg/km2 for the Yare and 0.77 Mg/km2 for the Tud.
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