The North Wyke Farm Platform(NWFP) for agri-environmental research in temperate grassland was established in the UK in 2010 (Orr et al. 2011). Here we describe the instrumentation and methodologies used to monitor the quantity and quality of drainage water at a total of 15 H-flumes draining 5 sub-catchments within three farmlets. Each of 15 flume laboratories is supplied with 3 kW of mains power and connected to both fibre optic and UHF (Ultra High Frequency) radio networks for data exchange. The radio data network also provides telemetry for rain gauges and soil temperature/moisture probes located away from the flumes and within the catchment blocks. Water flow is measured using bubbler flow meters and when flow is above a defined threshold level, water is pumped into bespoke 13-litre stainless steel bypass cells on a 15-minute cycle using bi-directional peristaltic pumps. A range of sensors located within the bypass cells measure the following water quality parameters: nitrate, ammonium, dissolved organic carbon, temperature, conductivity, turbidity, pH and dissolved oxygen. Total phosphorus and ortho phosphorus are measured at one flume in each farmlet. Networked auto-samplers are also provided at each flume site for the measurement of other wa-ter quality parameters as required. All data are logged and sent to a dedicated server at a 15 min resolution while a web front end allows advanced visualization capabilities and remote control of the entire system. The system is configured to allow for flexibility and future expansion to a wider range of parameters
