TOPCAT‐NP: a minimum information requirement model for simulation of flow and nutrient transport from agricultural systems

Future catchment planning requires a good understanding of the impacts of land use and management, especially with regard to nutrient pollution. A range of readily usable tools, including models, can play a critical role in underpinning robust decision-making. Modelling tools must articulate our process understanding, make links to a range of catchment characteristics and scales and have the capability to reflect future land-use management changes. Hence, the model application can play an important part in giving confidence to policy makers that positive outcomes will arise from any proposed land-use changes. Here, a minimum information requirement (MIR) modelling approach is presented that creates simple, parsimonious models based on more complex physically based models, which makes the model more appropriate to catchment-scale applications. This paper shows three separate MIR models that represent flow, nitrate losses and phosphorus losses. These models are integrated into a single catchment model (TOPCAT-NP), which has the advantage that certain model components (such as soil type and flow paths) are shared by all three MIR models. The integrated model can simulate a number of land-use activities that relate to typical land-use management practices. The modelling process also gives insight into the seasonal and event nature of nutrient losses exhibited at a range of catchment scales. Three case studies are presented to reflect the range of applicability of the model. The three studies show how different runoff and nutrient loss regimes in different soil/geological and global locations can be simulated using the same model. The first case study models intense agricultural land uses in Denmark (Gjern, 114 km2), the second is an intense agricultural area dominated by high superphosphate applications in Australia (Ellen Brook, 66 km2) and the third is a small research-scale catchment in the UK (Bollington Hall, 2 km2). Copyright © 2007 John Wiley & Sons, Ltd.

[1]  Keith Beven,et al.  Equifinality, data assimilation, and uncertainty estimation in mechanistic modelling of complex environmental systems using the GLUE methodology , 2001 .

[2]  Paul Quinn,et al.  Scale appropriate modelling: representing cause-and-effect relationships in nitrate pollution at the catchment scale for the purpose of catchment scale planning , 2004 .

[3]  A. Sharpley.  Prediction of Water-Extractable Phosphorus Content of Soil Following a Phosphorus Addition , 1982 .

[4]  Andrew P. Whitmore,et al.  Simulation of solute leaching in soils of differing permeabilities , 1991 .

[5]  K. Goulding.  Nitrate leaching from arable and horticultural land , 2000 .

[6]  O. F. Schoumans,et al.  Modeling Soil Phosphorus Levels and Phosphorus Leaching from Agricultural Land in the Netherlands , 2000 .

[7]  Andrew N. Sharpley,et al.  The Impact of Soil and Fertilizer Phosphorus on the Environment , 1987 .

[8]  Keith Beven,et al.  Spatial and temporal predictions of soil moisture dynamics, runoff, variable source areas and evapotranspiration for plynlimon, mid-wales. , 1993 .

[9]  E. Wood,et al.  Distributed watershed modeling of design storms to identify nonpoint source loading areas , 1999 .

[10]  K. Beven,et al.  A physically based, variable contributing area model of basin hydrology , 1979 .

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

[12]  W. Edwards,et al.  Lysimeter Study of Nitrate Leaching from a Corn‐Soybean Rotation , 2000 .

[13]  Andrew N. Sharpley,et al.  Practical and Innovative Measures for the Control of Agricultural Phosphorus Losses to Water: An Overview , 2000 .

[14]  Paul J. A. Withers,et al.  Soil phosphorus management and water quality: a UK perspective , 1998 .

[15]  L. M. Svendsen,et al.  Retention of nitrogen and phosphorus in a Danish lowland river system: implications for the export from the watershed , 1993, Hydrobiologia.

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

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

[18]  B. Kronvang,et al.  The export of particulate matter, particulate phosphorus and dissolved phosphorus from two agricultural river basins: Implications on estimating the non-point phosphorus load , 1992 .

[19]  Andrew N. Sharpley,et al.  The enrichment of soil phosphorus in runoff sediments. , 1980 .

[20]  Steven G. Anthony,et al.  “MIRSED” towards an MIR approach to modelling hillslope soil erosion at the national scale , 2001 .

[21]  S. Anthony,et al.  Catchment scale modelling of nitrate leaching , 1996 .

[22]  N. Peters,et al.  Nutrient transport to the Swan–Canning Estuary, Western Australia , 2001 .

[23]  John N. Quinton.  Reducing predictive uncertainty in model simulations: a comparison of two methods using the European Soil Erosion Model (EUROSEM) , 1997 .

[24]  Keith Beven,et al.  A manifesto for the equifinality thesis , 2006 .

[25]  C. Jordan,et al.  Increased predicted losses of phosphorus to surface waters from soils with high Olsen‐P concentrations , 2000 .

[26]  A. Edwards,et al.  Integrating soil phosphorus testing into environmentally based agricultural management practices , 1998 .

[27]  P. Brookes,et al.  Development of an Indicator for Risk of Phosphorus Leaching , 2000 .

[28]  Caspar J. M. Hewett,et al.  A multi-scale framework for strategic management of diffuse pollution , 2009, Environ. Model. Softw..

[29]  N. Peters,et al.  Trends in total phosphorus and total nitrogen concentrations of tributaries to the Swan–Canning Estuary, 1987 to 1998 , 2001 .

[30]  G. McCarty,et al.  Denitrification and degassing in groundwater estimated from dissolved dinitrogen and argon , 1998 .