This dataset includes data collected from the Bowl site located with the Pontbren study catchment in mid Wales, UK. The Bowl is an area of improved grassland and was instrumented between 2004 to 2010 and monitored as part of the Pontbren Catchment Study Land Use and Management Multi Scale Experimental Programme. Variables measured and included in this dataset are the drain flow from a field drain, overland flow runoff and soil water tension within the improved grassland hillslope. Other variables measured at the Bowl but not included in this dataset are: climatic data from an automatic weather station, precipitation, groundwater height, and soil moisture data (using a neutron probe); these other datasets are also available. Within this Pontbren Bowl study site folder are a series of sub-folders with different datasets all associated with the Bowl study site. The Bowl runoff folder includes all runoff data from the Bowl study site. Runoff from the Bowl in the form of overland and drain flow was monitored using a combination of tipping bucket and weir box monitoring systems. Flow is measured in litres/second (ls-1) and runoff data from the bowl was collected for the period end of 2004 to 2010. Differences in sampling time occurred throughout the monitoring period due to logger limitations. Changes in sampling time can be found by examining specific data files. Changes in the size of the bucket of the tipping bucket system also occurred during the monitoring period. It is considered that the weir boxes provide a more accurate prediction of the highest flows, however there are times when they are not operation. The Bowl tensiometers folder contains soil water tension (cm H2O) data collected from two transects with arrays of tensiometers measuring soil water tension at 10 cm, 30 cm and 50 cm depth. Soil water tension data for the Bowl study site exist for the period 2005-2009. Data are provided in the form of .txt files and generally split into 6 month blocks. Associated with each data point in the .txt file is a quality assurance code, QA code, in the adjacent column. Note that for the Bowl tensiometer data in the early years of monitoring data from both transects are provided in one file. From March 2008 onwards there is a reduction in the number of tensiometers installed and the data files are split. Files with BotQC in the title contain data from the lower array of tensiometers and files with TopQC in the title contain data from the array of tensiometers further up the hillslope of the Bowl study site. Details of the dataset and the quality assurance coding system are provided in the supporting documentation.