Hitchin GS Markyate FSA River Lee at Feildes Weir (Gauged) Amwell Loop, Tumbling Bay Weir DS Borehamwood Brook, Borehamwood Mimmshall Brook, North Mymms 
Mimmshall Brook, Mimmshall Brook Pishiobury Brook, Pishiobury Brook Radlett Brook, Radlett Rags Brook, Cheshunt, Rosedale way River Ash, Furneux Pelham River Ash, Little Hadham River Ash, Mardock River Beane, Walkern River Beane, Dane End River Beane, Watton at Stone River Beane, Hertford, Hartham Park River Bulbourne, Hemel Hempstead, Old Fishery Lane River Bulbourne, Hemel Hempstead, Two Waters Road River Chess, Rickmansworth River Colne, London Colney River Colne, Watford River Colne, Moor Lane River Gade, Hemel Hempstead, Bury Mill, River Gade, Croxley Green River Lee, Harpenden River Lee, Waterhall River Lee, Hoddesdon, Rye Bridge River Mimram, Whitwell River Mimram, Fulling Mill River Mimram, Panshanger River Quin, Braughing River Red, Redbourn River Red River Rib, Buntingford River Rib, Wadesmill River Stort, Bishops Stortford, Grange Paddocks River Stort, Harlow Mill River Ver, Markyate River Ver, Redbourn River Ver River Ver, Colney Street Small River Lee, Cheshunt, Windmill Lane Stevenage Brook, Bragbury Park Theobalds Brook, Cheshunt, Trinity Lane