The larger of pair of reservoirs which lie 3 miles (5 km) south southeast of Greenock in Inverclyde, Gryfe (or Gryffe) No.1 is located just below Loch Thom at a height of 186m (610 feet). It is retained by an earth embankment dam and extends to 68.3 ha (168 acres). The rather smaller Gryfe No.2 Reservoir lies immediately to the east. An Act of Parliament was passed authorising their construction in 1866 and they were completed in 1872, together with a tunnel which conveyed clean drinking water to Greenock, a town that had suffered from insanitary conditions since early in the 19th century, culminating in the typhus epidemic of 1864, which killed thousands. The tunnel is marked on the ground by a line of air shafts and emerges at Whinhill where there is a waterworks. Built by Greenock Water Trust, the reservoirs are now operated by Scottish Water and continue to supply drinking water. A recreational fishery on Gryfe No.1 for brown trout is managed by the Dunrod Angling Association.