Evaluating the risk of non-point source pollution from biosolids: integrated modelling of nutrient losses at field and catchment scales

A semi-distributed model, INCA, has been developed to determine the fate and distribution of nutrients in terrestrial and aquatic systems. The model simulates nitrogen and phosphorus processes in soils, groundwaters and river systems and can be applied in a semi-distributed manner at a range of scales. In this study, the model has been applied at field to sub-catchment to whole catchment scale to evaluate the behaviour of biosolid-derived losses of P in agricultural systems. It is shown that process-based models such as INCA, applied at a wide range of scales, reproduce field and catchment behaviour satisfactorily. The INCA model can also be used to generate generic information for risk assessment. By adjusting three key variables: biosolid application rates, the hydrological connectivity of the catchment and the initial P-status of the soils within the model, a matrix of P loss rates can be generated to evaluate the behaviour of the model and, hence, of the catchment system. The results, which indicate the sensitivity of the catchment to flow paths, to application rates and to initial soil conditions, have been incorporated into a Nutrient Export Risk Matrix (NERM).

[1]  P. Dillon,et al.  Effect of landscape form on export of dissolved organic carbon, iron, and phosphorus from forested stream catchments , 1997 .

[2]  Andrew N. Sharpley,et al.  A conceptual approach for integrating phosphorus and nitrogen management at watershed scales. , 2000 .

[3]  Andrew J. Wade,et al.  The Integrated Catchments model of Phosphorus dynamics (INCA-P), a new approach for multiple source assessment in heterogeneous river systems: model structure and equations , 2002 .

[4]  E. J. Wilson,et al.  A semi-distributed ntegrated itrogen model for multiple source assessment in tchments (INCA): Part I — model structure and process equations , 1998 .

[5]  Caspar J. M. Hewett,et al.  Modelling and managing critical source areas of diffuse pollution from agricultural land using flow connectivity simulation , 2005 .

[6]  P Whitehead,et al.  Strategic management of non-point source pollution from sewage sludge. , 2003, Water science and technology : a journal of the International Association on Water Pollution Research.

[7]  P G Whitehead,et al.  Steady state and dynamic modelling of nitrogen in the River Kennet: impacts of land use change since the 1930s. , 2002, The Science of the total environment.

[8]  C. Neal,et al.  On modelling the effects of afforestation on acidification in heterogeneous catchments at different spatial and temporal scales , 2001 .

[9]  Penny J Johnes,et al.  MODELLING THE IMPACT OF LAND USE CHANGE ON WATER QUALITY IN AGRICULTURAL CATCHMENTS , 1997 .

[10]  E. J. Wilson,et al.  A semi-distributed integrated flow and nitrogen model for multiple source assessment in catchments (INCA): Part II — application to large river basins in south Wales and eastern England , 1998 .

[11]  A. Edwards,et al.  Modelling instream nitrogen variability in the Dee catchment, NE Scotland. , 2001, The Science of the total environment.

[12]  Keith Beven,et al.  Changing ideas in hydrology — The case of physically-based models , 1989 .

[13]  Ann Louise Heathwaite,et al.  Nitrate:processes, patterns and management , 1995 .

[14]  P. Whitehead,et al.  Water quality and ecology of the River Lee: mass balance and a review of temporal and spatial data , 2004 .

[15]  George M. Hornberger,et al.  On modeling the mechanisms that control in‐stream phosphorus, macrophyte, and epiphyte dynamics: An assessment of a new model using general sensitivity analysis , 2001 .

[16]  Heathwaite,et al.  Characterising phosphorus loss in surface and subsurface hydrological pathways , 2000, The Science of the total environment.

[17]  C. Neal,et al.  Assessing nitrogen dynamics in European ecosystems, integrating measurement and modelling: conclusions , 2004 .

[18]  Paul Whitehead,et al.  INCA Modelling of the Lee System: strategies for the reduction of nitrogen loads , 2002 .

[19]  W. A. Virtue,et al.  Modelling nitrogen dynamics and distributions in the River Tweed, Scotland: an application of the INCA model , 2002 .

[20]  A. Louise Heathwaite,et al.  Making process-based knowledge useable at the operational level: a framework for modelling diffuse pollution from agricultural land , 2003, Environ. Model. Softw..

[21]  Paul Quinn,et al.  The Nutrient Export Risk Matrix (NERM) for strategic application of biosolids to agricultural land , 2003 .

[22]  Caspar J. M. Hewett,et al.  Towards a nutrient export risk matrix approach to managing agricultural pollution at source , 2004 .

[23]  Andrew N. Sharpley,et al.  The conceptual basis for a decision support framework to assess the risk of phosphorus loss at the field scale across Europe , 2003 .

[24]  A. Wade,et al.  Excess nitrogen leaching and C/N decline in the Tillingbourne catchment, southern England , 2002 .

[25]  Andrew N. Sharpley,et al.  Critical source area controls on water quality in an agricultural watershed located in the Chesapeake basin. , 2000 .

[26]  P. G. Whitehead,et al.  Modelling nitrate from agriculture into public water supplies , 1990 .