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Relationships between chloride and major cations in precipitation and streamwaters in the Windermere catchment (English Lake District)
Author(s) -
SUTCLIFFE D. W.,
CARRICK T. R.
Publication year - 1983
Publication title -
freshwater biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 156
eISSN - 1365-2427
pISSN - 0046-5070
DOI - 10.1111/j.1365-2427.1983.tb00002.x
Subject(s) - streams , soil water , hydrology (agriculture) , precipitation , slates , sedimentary rock , volcanic rock , geology , leaching (pedology) , environmental chemistry , geochemistry , chemistry , volcano , soil science , computer network , physics , meteorology , computer science , geotechnical engineering
SUMMARY. 1. The ranges of concentrations for pH, CV. Na + . K + Ca 2+ , Mg 2+ are given for streams draining igneous rocks (Borrowdale Volcanics) and sedimentary muds, silts and shales (Silurian Slates) in the catchment of Windermere (230 km 2 ). Impacts on the biota are briefly discussed. Relative contributions of inputs from various sources are examined: precipitation, rocks and soils, sewage, deicing salt used on highways./ 2. In bulk precipitation, ratios of Na + /CV (as μequiv. I −1 ) ranged from 0.41 to 1.83 over a 2‐year period. The overall volume‐weighted mean ratio was 0.86, as in seawater, hut 2 ′4% (1975) and 5.7% (1976) of Cl − was non‐marine in origin, being balanced by H + (in winter), K and Ca 2+ (in summer). In moorland headwater streams, CI − is largely derived from precipitation: there is a pronounced annual cycle of midwinter high and midsummer low concentrations unrelated to stream discharge. Na* and K + display similar cycles but Na + , Ca2 + and Mg 2+ (and pH) are discharge‐related due to leaching from rocks and soils: 10–20% Na+, 15–17% Mg 2+ and 65–75% Ca 2+ are so‐derived whereas K+ comes from precipitation. Na + /Cl + ratios in streams on Borrowdale Volcanics alter seasonally, with midsummer values >1. Lower values occur in streams on Silurian Slates where some CI − is apparently derived from rocks. 3. Seasonal changes in streamwater concentrations of Cl, Na 4 andK + are exponentially related to time. Instantaneous rates of change i day‐1 1 ) are compared in relation to position in the catchment and inputs from anthropogenic sources. Deicing salt has raised (10–100‐fold) the concentrations of Na * and Cl − in streams on mountain passes; the effects persist throughout the year.