Newby is a 12.5 km² subcatchment, located within the Lyvennet subcatchment. The Lyvennet subcatchment is predominantly improved grassland over Calcareous (limestone) bedrock, and has a maximum altitude of 392 m. the River Lyvennet is classed as waterbody GB102076070840 under the Water Framework Directive. The Lyvennet catchment is a priority area for the England Catchment Sensitive Farming Delivery Initiative which aims to reduce diffuse pollution from agriculture. The Newby catchment contains the upper reaches of Newby Beck, which flows into Newby Beck near Newby village. Improved grassland makes up the majority of the area (76%), with small areas of acid grassland (10%) and arable land (6%). Mean elevation is 234 m, and slopes are moderate (7%).
The Newby catchment contains two subcatchments, a mitigation subcatchment and a control subcatchment, each 2 km². The mitgation subcatchment contains 3 farms, which have been the focus of much of the work within the DTC project in Newby.