Hydrograph separation using ionic concentration measurement

0453902 - ÚH 2016 eng C - Conference Paper (international conference)
Tesař, Miroslav - Vondrka, A. - Šír, M.
Hydrograph separation using ionic concentration measurement.
2015.
[26th IUGG General Assembly. Praha (CZ), 22.06.2015-02.07.2015]
Institutional support: RVO:67985874
Keywords : runoff hydrology * hydrograph separation * hydrochemical tracers * cations leaching
Subject RIV: DA - Hydrology ; Limnology

The method of hydrograph separation considered for this study is a method to distinguish old and new water in a stream. This method is based on the fact that the ion content of the water depends on the time water has spent in the soil structure – there is a difference in the ionic composition between the groundwater (old water causing the base flow) and that of a given storm (new water). Groundwater has a greater content of Na+ ions than that of K+ ions, which is caused by a greater sorption of K+ ions in the soil and by subsequent uptake of K+ ions by plants. This means that in the storm water the ratio of Na+ and K+ ions is significantly lower than that in the ground water. Other quantities that are expected to vary with the ratio of the base flow to the storm runoff are contents of particular dissolved solids. These manifest themselves by variation of the electrical conductivity of water. It follows that a hydrograph can be separated into a new- and old-water part by means of measuring of the electrochemical properties of out-flowing water – Na+ and K+ ion content, electrical conductivity, provided that these quantities in the storm water are known. In dry and warm period, the age of water flowing into the stream can be quantified, since in the period when the flow rate decreases, also decreases the content of potassium ions in the water flowing from the soil into the stream. This is because consumption of potassium in the soil water by transpiring plants. Therefore, the age of the soil water can be measured by the concentration of potassium ions in the water flowing from the basin.
Permanent Link: http://hdl.handle.net/11104/0254607