Articles | Volume 8, issue 1
Hydrol. Earth Syst. Sci., 8, 88–97, 2004
Hydrol. Earth Syst. Sci., 8, 88–97, 2004

  29 Feb 2004

29 Feb 2004

Temporal variability in phosphorus transfers: classifying concentration–discharge event dynamics

P. Haygarth1, B.L. Turner5,1, A. Fraser2, S. Jarvis1, T. Harrod2, D. Nash3, D. Halliwell3, T. Page4, and K. Beven4 P. Haygarth et al.
  • 1Institute of Grassland and Environmental Research, North Wyke Research Station, Okehampton, Devon, EX20 2SB, UK
  • 2National Soil Resources Institute, North Wyke Research Station, Okehampton, Devon, EX20 2SB, UK
  • 3Agriculture Victoria, RMB 2460, Hazeldean Road, Ellinbank, Victoria 3821, Australia
  • 4Environmental Science Department, University of Lancaster, Lancaster LA1 4YQ, UK
  • 5Soil and Water Science Department, University of Florida, Gainesville, Florida 32611, USA
  • E-mail for corresponding author:

Abstract. The importance of temporal variability in relationships between phosphorus (P) concentration (Cp) and discharge (Q) is linked to a simple means of classifying the circumstances of Cp–Q relationships in terms of functional types of response. New experimental data at the upstream interface of grassland soil and catchment systems at a range of scales (lysimeters to headwaters) in England and Australia are used to demonstrate the potential of such an approach. Three types of event are defined as Types 1–3, depending on whether the relative change in Q exceeds the relative change in Cp (Type 1), whether Cp and Q are positively inter-related (Type 2) and whether Cp varies yet Q is unchanged (Type 3). The classification helps to characterise circumstances that can be explained mechanistically in relation to (i) the scale of the study (with a tendency towards Type 1 in small scale lysimeters), (ii) the form of P with a tendency for Type 1 for soluble (i.e., <0.45 μm P forms) and (iii) the sources of P with Type 3 dominant where P availability overrides transport controls. This simple framework provides a basis for development of a more complex and quantitative classification of Cp–Q relationships that can be developed further to contribute to future models of P transfer and delivery from slope to stream. Studies that evaluate the temporal dynamics of the transfer of P are currently grossly under-represented in comparison with models based on static/spatial factors.

Keywords: phosphorus, concentration, discharge, lysimeters, temporal dynamics, overland flow