Low flow water chemistry in forested and pasture catchments, Mawheraiti River, Westland
作者:
M. P. Mosley,
L. K. Rowe,
期刊:
New Zealand Journal of Marine and Freshwater Research
(Taylor Available online 1981)
卷期:
Volume 15,
issue 3
页码: 307-320
ISSN:0028-8330
年代: 1981
DOI:10.1080/00288330.1981.9515926
出版商: Taylor & Francis Group
关键词: Mawheraiti River;forests;pasture;harvesting;burning;stream flow;water analysis (chemical);calcium;magnesium;sodium;potassium;nitrate;phosphate;ammonium
数据来源: Taylor
摘要:
Water samples taken at 19 locations in the Mawheraiti River catchment at weekly intervals during 1979–80 were analysed for sodium, magnesium, potassium, calcium, phosphate, nitrate, and ammonium ion concentrations and for electrical conductivity. Seasonal discharge effects were apparent, and lithology and land management practice also influenced solute concentrations. Solute concentrations were generally very low; nitrate and soluble phosphate were rarely greater than 0.05 mg.L‐1and ammonium was rarely greater than 0.01 mg.L‐1. The 4 major cations (Na, Mg, K, and Ca) usually summed to less than 6 mg.L‐1much of which was supplied by precipitation. Forest management (clearfelling and slash‐burning) caused significant increases in solute concentrations, but concentrations declined rapidly during succeeding months and approached pretreatment levels after 2–3 years. The higher concentrations associated with forest management in small experimental catchments were rapidly diluted downstream; together with the low natural solute concentrations this suggests that harmful downstream effects of management practices are unlikely under low flow conditions.
点击下载:
PDF (1018KB)
返 回