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Stream nitrate levels in a small catchment in south west England over a period of 35 years (1970–2005)
Author(s) -
Burt Tim P.,
Worrall Fred
Publication year - 2009
Publication title -
hydrological processes
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.222
H-Index - 161
eISSN - 1099-1085
pISSN - 0885-6087
DOI - 10.1002/hyp.7314
Subject(s) - drainage basin , nitrate , hydrology (agriculture) , environmental science , period (music) , streams , historical record , range (aeronautics) , catchment hydrology , physical geography , geography , geology , ecology , history , computer network , physics , materials science , cartography , geotechnical engineering , computer science , acoustics , composite material , memoir , biology , art history
This study considers a 35‐year record of streamwater nitrate concentration in a small agricultural catchment in south west England (Slapton Wood). The study revisits earlier work to assess whether upward trends have been maintained and how the controls upon streamwater concentration have been altered. The study has shown that (1) the catchment has reached a new position of equilibrium and increases in nitrate concentration have lessened; (2) the occurrence of severe drought in the record means that records of less than a decade are misleading and only long‐term records can illustrate changes of state; (3) the change of state observed in the catchment is illustrated in the switching of long‐term memory effects from a negative to a positive annual memory and (4) several significant long‐term impulsivity relationships with rainfall that become insignificant over the course of the study period. The study shows the importance of long‐term records in understanding changes in state in catchments and understanding the time constants of a range of driving processes. Copyright © 2009 John Wiley & Sons, Ltd.