Analysis and online real-time integrated modelling of nitrate processes in the whole freshwater cycle

Nitrate pollution in freshwater, which is mainly from agricultural activities, remains an international problem. It threatens environment, economics and human health in the UK. Nitrate concentrations are more than 50 mg NO3 per liter EU drinking water standard with a rising trend in many UK freshwaters (groundwater and surface water). In the freshwater cycle, nitrate leached from the soil (after soil nitrogen (N) transformations, such as nitrification, denitrification and plant uptake) can (a) quickly discharge into surface streams, or (b) slowly transport through the unsaturated zone (from the base of the soil layer to water table) and the saturated zone before reaching boreholes, springs and streams. Groundwater and stream water may heavily influence each other's qualities through the interactions between them in the hyporheic zone (a zone below and adjacent to a streambed).
Through recent research, it has become increasingly clear that it could take decades for leached nitrate from the soil to discharge into freshwaters due to nitrate storage and its potentially long time lag in the unsaturated and saturated zones. However, this time lag is rarely considered in current water nitrate management and policy development, although there is an urgent need to do so because of environmental and legislative pressures. While we now have a much better, although still incomplete, understanding of nitrate processes in each separate component of the freshwater cycle than before; further holistic research is required to advance our knowledge of nitrate processes in the interconnected whole cycle.
I propose to investigate the nitrate transport and major N transformations in the soil and in the unsaturated, saturated and hyporheic zones by developing an integrated modelling method. A prototype of online and real-time modelling system will be developed for demonstration purposes.
The development of such an integrated modelling method is a major challenge. It has never been tried before with such level of complexity involving the integration of soil, hydrology, hydrogeology, biogeochemistry and landscape sciences. However, it is worth pursuing with the reward of entirely novel insights into the behaviour of nitrate in the interconnected whole freshwater cycle, and direct benefit to academic society and water nitrate management policy makers, thus indirectly reducing the economic costs due to water nitrate problems (e.g. costs of treating nitrate in drinking water, and water nitrate related human diseases). The methods and tools developed in this research can be transferable to other areas.
The Eden Valley, where I have developed numerical models in simulating runoff, groundwater recharge, and nitrate transport in groundwater and in the unsaturated zone, will be used as a testing area in this study. As it is also one of the catchments being studied in the NERC Macronutrient Cycles, and DEFRA Demonstration Test Catchment programmes, this project will be a valuable contribution to these ongoing programmes. This also means that there is a large amount of available data.
The concept of real-time (as described here) does not necessarily imply a short modelling interval, but rather a way for automatically modelling and immediately delivering results and models. The novel online and real-time modelling method to be demonstrated in this project will greatly facilitate the efficient communication between stakeholders in a very cost-effective way, and have a potential to increase the participation of the catchment's community (including farmers and the general public) in nitrate management policy development, by publishing online information updated automatically in real-time.

In a long term, the direct beneficiaries of knowledge arising from this research are anticipated to be DEFRA and the Environment Agency who will be able to use the outputs (scientific findings, methods and models) from this research to inform and formulate effective policy on nitrate management. An online real-time modelling system (OneRTM) for nitrate processes in freshwaters that will be demonstrated in the project can automatically update the information through the internet in real-time, thus improving the communication between policy-makers and scientists and hence the efficiency of policy-making.
The achievement of this long-term goal will need two stages:
- Stage 1: start to engage with DEFRA and the Environment Agency through their representatives from the time of making the project plan, to make sure that the project is to be carried out in the right direction and its outputs will be useful in policy-making. The intermediate and final outputs of the project will be demonstrated to the representatives. The aim of this stage is to show policy-makers that the nitrate storage and time lag can not be ignored when making the nitrate management policies for both groundwater and surface water, and that the methods and models developed in this project work well in the testing area (the Eden).
- Stage 2: Policy-makers begin to consider the nitrate storage and time lag in their nitrate management decision making, with the support of applying the methods and models developed in this study in the different catchments in conjunction with their exiting methods or tools. Finally the outputs of this project will be used routinely to support the decision making.
The stage 2 needs more efforts and time (from both scientist and policy-maker sides) than this proposed study can actually afford. Therefore, this project will focus only on the stage 1.
Our colleagues from the Environment Agency, NERC Macronutrient Cycles Programme (MCP), DEFRA Demonstration Test Catchment (DTC) programme, BGS, universities and other organisations will also directly benefit from the outputs of this proposal by using the outputs of this proposed research in their own catchment-based and nitrate process related research..
Researchers will benefit from the introduction of the novel OneRTM tools into their modelling studies. In OneRTM, models are always up to date automatically; end-users get immediate results and modelling functions via the web; and the system maintenance cost is very low.
The Eden catchment community will benefit from the novel technology of online real-time modelling to be demonstrated in this project. The online information (in easily readable formats, such as pictures or maps) updated in real-time can help them to plan for agricultural activities. For example, The online real-time soil moisture deficit maps produced in this study will help farmers plan irrigation more effectively.
As discussed above, academia and policy-makers will directly benefit from the outputs of this research, thus resulting in positive impacts on the quality of freshwater and environment. The UK economy will thus indirectly benefit from this study. For example, with less nitrate into freshwaters, less money will be spent on removing nitrate from drinking water, and on treating the nitrate related human health problems. In addition, the introduction of OneRTM into the numerical modelling routine will make it much cheaper to always keep models up to data.
In order to engage with these beneficiaries, the PI will use the methods or activities (as noted in the Pathways to Impact) of project meeting with a project advisory panel, attending the activities of DEFRA DTC programme in the Eden, commercialisation, creating website, and BGS public outreach, etc.