In October 2016, Hurricane Matthew struck Eastern Canada resulting in excessively high-water levels in the Exploits River in Central Newfoundland. Water levels in the tailrace (below the dam) of Newfoundland Labrador Hydro’s Bishops Falls Hydro Generating Plant rose to levels just below the powerhouse floor and entered the generator turbine pits. Sump pumps were deployed but did not prevent the large volume of water from entering conduits containing electrical cables for the generators. These generators experienced significant damage and took more than a month to repair and return to service. Not only was the repair cost substantial, but the company also experienced loss in revenue while these generators were offline.
After service was fully restored, it was determined that a solution was needed to reduce the likelihood of damage from similar flooding in the future. Based on published technical data by Polywater, it was determined that Polywater’s FST Duct Sealant would be the best option. It was engineered to block water or gases under pressure for long periods of time, unlike common expanding foams on the market. It also had been rigorously tested in both laboratory and field conditions for over 20 years to support its performance claims.
In April 2018, high water levels in the Exploits River once again threatened the Bishops Falls Generating Plant. Levels rose quickly as the region experienced heavy rains and faster than normal spring runoff from snowmelt in its watershed. Levels in the tailrace quickly reached the same as those experienced in the 2016 Hurricane Mathew flood. This time, however, with the help of Polywater FST, no water entered the generator turbine pits through the now sealed conduits. Minimal water did seep through cracks in the concrete, however, this was easily controlled with the help of small sump pumps and the generators remained dry for the duration of the event.
The water remained high for several days before gradually receding. Testing indicated that no damage occurred to any of the seven generators. All are back in service to again provide reliable electrical service to Newfoundland Labrador Hydro customers.