Changes in point and diffuse source phosphorus inputs to the River Frome (Dorset, UK) from 1966 to 2006

Bowes, Michael J.; Smith, J.T.; Jarvie, Helen P.; Neal, Colin; Barden, Ruth

doi:10.1016/j.scitotenv.2008.11.026

Cited by 50 publications

(76 citation statements)

References 37 publications

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“…To reduce the negative impacts of excess P, watershed managers develop strategies to attain a target P level that can satisfy the designated use of a water body through control of anthropogenic sources (Freedman et al, 2008;Chen et al, 2012;Bowes et al, 2015). Setting P source reduction targets and identifying remedial options rely on appropriate and accurate apportionment of P loads to point (PS) and nonpoint sources (NPS) (Bowes et al, 2009a;Jarvie et al, 2012;Chen et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

“…Lumped models, which usually provide a simplified understanding of nutrient sources and transfer dynamics from the watershed to rivers, also require information on primary watershed attributes (e.g., land use, population, and agricultural census data), as well as nutrient discharge from sewage treatment facilities and industries. However, accurate datasets spanning a number of decades are relatively rare for most watersheds, especially in developing countries experiencing the most severe nutrient pollution (Freedman et al, 2008;Bowes et al, 2009a). The source apportionment results determined from current models are also subject to considerable uncertainty since measured riverine P loads are a mixture of P-rich waters having different ages Jarvie et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

“…Based on the fundamental hydrological differences between nutrient inputs from PS and NPS to rivers, a load apportionment model (LAM) may be developed for statistically quantifying point and nonpoint source nutrient inputs as a power-law function of river discharge (Bowes et al, 2008(Bowes et al, , 2009a(Bowes et al, , 2009b(Bowes et al, , 2010(Bowes et al, , 2014Greene et al, 2011;Chen et al, 2013). The LAM does not require detailed watershed attribute information and can potentially be applied to any dataset comprised of paired P concentrations and river discharge measurements.…”

Section: Introductionmentioning

confidence: 99%

“…The LAM does not require detailed watershed attribute information and can potentially be applied to any dataset comprised of paired P concentrations and river discharge measurements. This approach has been successfully applied to a wide range of watersheds in England, Ireland, U.S.A. and China (Bowes et al, 2008(Bowes et al, , 2009a(Bowes et al, , 2009b(Bowes et al, , 2010(Bowes et al, , 2014Greene et al, 2011;Jarvie et al, 2012;Chen et al, 2013). In terms of long-term riverine P source apportionment, however, existing LAM applications encounter some important limitations.…”

Section: Introductionmentioning

confidence: 99%

“…In conventional applications of LAMs, the remobilization of P from the river channel is incorrectly assigned to the nonpoint source input load, which leads to overestimation of P from NPS and underestimation of PS. A second limitation for conventional LAM application is that they are usually validated from the results of other models, commonly export coefficient models (Bowes et al, 2008(Bowes et al, , 2009a(Bowes et al, , 2009b(Bowes et al, , 2010. However, it remains a challenge to verify LAM results using export coefficient based models for many watersheds since long-term specific P export coefficients are not available or rapidly changing over time.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Reconstructing historical changes in phosphorus inputs to rivers from point and nonpoint sources in a rapidly developing watershed in eastern China, 1980–2010

Chen

Guo

et al. 2015

Science of The Total Environment

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Reconstructing historical changes in phosphorus inputs to rivers from point and nonpoint sources in a rapidly developing watershed in eastern China, 1980–2010

Chen

Guo

et al. 2015

Science of The Total Environment

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Temporal variability in nutrient concentrations and loads in the River Tamar and its catchment (SW England) between 1974 and 2004

Tappin

Mankasingh

McKelvie

et al. 2012

Environ Monit Assess

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This study reports the results from the analyses of a 30-year (1974-2004) river water quality monitoring dataset for NO x -N (NO₃-N + NO2-N), NH₄-N, PO₄-P and SiO₂-Si at the tidal limit of the River Tamar (SW England), an agriculturally dominated and sparsely populated catchment. Annual mean concentrations of NH4-N, PO₄-P and SiO₂-Si were similar to other rural UK rivers, while annual mean concentrations of NO x -N were clearly lower. Estimated values for the 1940s were much lower than for those of post-1974, at least for NO₃-N and PO₄-P. Flow-weighted mean concentrations of PO₄-P decreased by approximately 60 % between 1974 and 2004, although this change cannot be unequivocally ascribed to either PO₄-P stripping from sewage treatment work effluents or reductions in phosphate fertiliser applications. Lower-resolution sampling (to once per month) in the late 1990s may also have led to the apparent decline; a similar trend was also seen for NH4-N. There were no temporal trends in the mean concentrations of NO x -N, emphasising the continuing difficulty in controlling diffuse pollution from agriculture. Concentrations of SiO₂-Si and NO x -N were significantly and positively correlated with river flows ≤15 m(3) s(-1), showing that diffuse inputs from the catchment were important, particularly during the wet winter periods. In contrast, concentrations of PO₄-P and NH4-N did not correlate across any flow window, despite the apparent importance of diffuse inputs for these constituents. This observation, coupled with the absence of a seasonal (monthly) cycle for these nutrients, indicates that, for PO₄-P and NH4-N, there were no dominant sources and/or both undergo extensive within-catchment processing. Analyses of nutrient fluxes reveal net losses for NO₃-N and SiO₂-Si during the non-winter months; for NO3-N, this may be due to denitrification. Areal fluxes of NO x -N from the catchment were towards the higher end of the range for the UK, while NH₄-N and PO₄-P were closer to the lower end of the ranges for these nutrients. These data, taken together with information on sestonic chlorophyll a, suggest that water quality in the lower River Tamar is satisfactory with respect to nutrients. Analyses of these monitoring data, which were collected at considerable logistical and monetary cost, have revealed unique insights into the environmental behaviour of key nutrients within the Tamar catchment over a 30-year period.

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The application of high temporal resolution data in river catchment modelling and management strategies

Crockford

O’Riordain

Taylor

et al. 2017

Environ Monit Assess

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Modelling changes in river water quality, and by extension developing river management strategies, has historically been reliant on empirical data collected at relatively low temporal resolutions. With access to data collected at higher temporal resolutions, this study investigated how these new dataset types could be employed to assess the precision and accuracy of two phosphorus (P) load apportionment models (LAMs) developed on lower resolution empirical data. Predictions were made of point and diffuse sources of P across ten different sampling scenarios. Sampling resolution ranged from hourly to monthly through the use of 2000 newly created datasets from high frequency P and discharge data collected from a eutrophic river draining a 9.48 km catchment. Outputs from the two LAMs were found to differ significantly in the P load apportionment (51.4% versus 4.6% from point sources) with reducing precision and increasing bias as sampling frequency decreased. Residual analysis identified a large deviation from observed data at high flows. This deviation affected the apportionment of P from diffuse sources in particular. The study demonstrated the potential problems in developing empirical models such as LAMs based on temporally relatively poorly-resolved data (the level of resolution that is available for the majority of catchments). When these models are applied ad hoc and outside an expert modelling framework using extant datasets of lower resolution, interpretations of their outputs could potentially reduce the effectiveness of management decisions aimed at improving water quality.

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Changes in point and diffuse source phosphorus inputs to the River Frome (Dorset, UK) from 1966 to 2006

Cited by 50 publications

References 37 publications

Reconstructing historical changes in phosphorus inputs to rivers from point and nonpoint sources in a rapidly developing watershed in eastern China, 1980–2010

Reconstructing historical changes in phosphorus inputs to rivers from point and nonpoint sources in a rapidly developing watershed in eastern China, 1980–2010

Temporal variability in nutrient concentrations and loads in the River Tamar and its catchment (SW England) between 1974 and 2004

The application of high temporal resolution data in river catchment modelling and management strategies

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