Measure: River Thames at Marlow Lock - level-stage-i-15_min-mASD
Water Level (Stage) measured relative to stage datum in mASD every 15 minutes (instantaneous)
API
Get recent readings: http://environment.data.gov.uk/flood-monitoring/id/measures/2499TH-level-stage-i-15_min-mASD/readings?_sorted&_limit=500