Defining the sources of low-flow phosphorus transfers in complex catchments

Arnscheidt, Joerg; Jordan, Phillip; Li, S.; McCormick, S.; McFaul, R.; McGrogan, H.; Neal, Margaret; Sims, J. T.

doi:10.1016/j.scitotenv.2007.03.036

Cited by 78 publications

(56 citation statements)

References 25 publications

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“…However, when this strategy was changed to sample during overnight periods (18:00 to 08:00), the resulting sample sets tended to over-estimate annual load due to higher TP concentrations as observed with the 20 min data during non-storm periods f01a and f01b 20 f01a and f01b Fig. 2b and may be attributed both to a decline in biological activity at night leading to reduced uptake of P and (more likely - Arnscheidt et al, 2007) an increase in household activity either side of the working day and hence a peak in point source pressures. A compromise was shown to be a 12 h sampling The improved load estimates using the sub-daily approaches are directly attributable to the increased probability of capturing short term fluctuations in concentration.…”

Section: Resultsmentioning

confidence: 92%

Technical Note: Assessing a 24/7 solution for monitoring water quality loads in small river catchments

Jordan

Cassidy

2011

Hydrol. Earth Syst. Sci.

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Abstract. Quantifying nutrient and sediment loads in catchments is difficult owing to diffuse controls related to storm hydrology. Coarse sampling and interpolation methods are prone to very high uncertainties due to under-representation of high discharge, short duration events. Additionally, important low-flow processes such as diurnal signals linked to point source impacts are missed. Here we demonstrate a solution based on a time-integrated approach to sampling with a standard 24 bottle autosampler configured to take a sample every 7 h over a week according to a Plynlimon design. This is evaluated with a number of other sampling strategies using a two-year dataset of sub-hourly discharge and phosphorus concentration data. The 24/7 solution is shown to be among the least uncertain in estimating load (inter-quartile range: 96 % to 110 % of actual load in year 1 and 97 % to 104 % in year 2) due to the increased frequency raising the probability of sampling storm events and point source signals. The 24/7 solution would appear to be most parsimonious in terms of data coverage and certainty, process signal representation, potential laboratory commitment, technology requirements and the ability to be widely deployed in complex catchments.

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Section: Resultsmentioning

confidence: 92%

Technical Note: Assessing a 24/7 solution for monitoring water quality loads in small river catchments

Jordan

Cassidy

2011

Hydrol. Earth Syst. Sci.

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“…Jordan et al (2005aJordan et al ( , 2007a used this technology in the border area of Ireland to provide a typology of river P transfers. Arnscheidt et al (2007) used data from the same sub-catchments to define the sources of low flow P transfers. Several other studies have also used bankside analysis to define the magnitude of P transfers from point and diffuse sources at diurnal, event, seasonal and annual scales (Palmer-Felgate et al, 2008;Wade et al, 2012;Donn et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Using high-resolution phosphorus data to investigate mitigation measures in headwater river catchments

Campbell

Jordan

Arnscheidt

2015

Hydrol. Earth Syst. Sci.

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Abstract. This study reports the use of high-resolution water quality monitoring to assess the influence of changes in land use management on total phosphorus (TP) transfers in two 5 km 2 agricultural sub-catchments. Specifically, the work investigates the issue of agricultural soil P management and subsequent diffuse transfers at high river flows over a 5-year timescale. The work also investigates the phenomenon of low flow P pollution from septic tank systems (STSs) and mitigation efforts -a key concern for catchment management. Results showed an inconsistent response to soil P management over 5 years with one catchment showing a convergence to optimum P concentrations and the other an overall increase. Both catchments indicated an overall increase in P concentration in defined high flow ranges. Low flow P concentration showed little change or higher P concentrations in defined low flow ranges despite replacement of defective systems and this is possibly due to a number of confounding reasons including increased housing densities due to new-builds. The work indicates fractured responses to catchment management advice and mitigation and that the short to medium term may be an insufficient time to expect the full implementation of policies (here defined as convergence to optimum soil P concentration and mitigation of STSs) and also to gauge their effectiveness.

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“…Based on a wealth of evidence demonstrating the hydrologic controls on P transport and delivery [7][8][9] , the widespread assumption is that P loads mobilized during storm events equate to non-point sources delivered via run-off and erosion from the land surface 10,11 . Loads measured under low flows are assumed to equate to the contributions from point-source effluent discharges, together with any 'background' baseflow groundwater contributions 12,13 .…”

Section: Introductionmentioning

confidence: 99%

Within-River Phosphorus Retention: Accounting for a Missing Piece in the Watershed Phosphorus Puzzle

Jarvie

Sharpley

Scott

et al. 2012

Environ. Sci. Technol.

100

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The NERC and CEH trademarks and logos ('the Trademarks') are registered trademarks of NERC in the UK and other countries, and may not be used without the prior written consent of the Trademark owner. ABSTRACTThe prevailing 'puzzle' in watershed phosphorus (P) management is how to account for the nonconservative behavior (retention and remobilization) of P along the land-freshwater continuum. This often hinders our attempts to directly link watershed P sources with their water quality impacts. Here, we examine aspects of within-river retention of wastewater effluent P and its remobilization under high flows. Most source apportionment methods attribute P loads mobilized under high flows (including retained and remobilized effluent P) as non-point agricultural sources. We present a new simple empirical method which uses chloride as a conservative tracer of wastewater effluent, to quantify within-river retention of effluent P, and its contribution to river P loads, when remobilized under high flows. We demonstrate that within-river P retention can effectively mask the presence of effluent P inputs in the water quality record. Moreover, we highlight that by not accounting for the contributions of retained and remobilized effluent P to river storm-flow P loads, existing source apportionment methods may significantly over-estimate the non-point agricultural sources and under-estimate wastewater sources in mixed land-use watersheds. This has important implications for developing 2 effective watershed remediation strategies, where remediation needs to be equitably and accurately apportioned among point and non-point P contributors.

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Defining the sources of low-flow phosphorus transfers in complex catchments

Cited by 78 publications

References 25 publications

Technical Note: Assessing a 24/7 solution for monitoring water quality loads in small river catchments

Technical Note: Assessing a 24/7 solution for monitoring water quality loads in small river catchments

Using high-resolution phosphorus data to investigate mitigation measures in headwater river catchments

Within-River Phosphorus Retention: Accounting for a Missing Piece in the Watershed Phosphorus Puzzle

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