The Wettest August—Ever
The storms that saturated our watershed this summer broke records. In August, parts of our watershed received more than 300 percent of their normal rainfall. That resulted in some reservoir basins getting nearly one-third of a typical year’s rain in about 30 days.
Based on 90 years of water supply data, August 2018 is now the wettest August on record. The effect of that record rainfall is shown in the chart below, which shows normal runoff for August and the actual total runoff for each of our six reservoirs in our Catskill/Delaware System this August.
The storms caused the reservoir system to refill. At its peak the system was 101.7 percent full on Aug. 19. As a result, we have been making large releases of water to the rivers and creeks downstream of our reservoirs. These releases, paired with the water we’re sending to customers in NYC, are intended to draw the reservoirs down. A number of interstate agreements and protocols call for some reservoirs to aim for a target storage of less than 100 percent during much of the year.
Our wet summer underscores the amount of unpredictability that comes with operating our vast water supply. More wet weather and uncertainty lies ahead. On Monday, our watershed received several inches of rain from the remnants of Hurricane Gordon. Our meteorologists and operations staff are also closely tracking Hurricane Florence, which is forecast to hit North Carolina later this week and potentially deliver some moderate rainfall to the watershed next week.
These periods of unusually wet weather can be challenging. Our operations staff need to carefully track storms and adjust valves on short notice. The workers who operate our seven wastewater treatment plants upstate often work extra hours to ensure their plants can adjust to the additional inflow from heavy rainstorms. And, instrumentation experts venture high into the mountains or knee-deep into streams to fix the weather stations and gauges that send us vital data in near-real time.
More record setting rain events are sure to come and our scientists will continue track how these storms affect water quality in our reservoirs, ensuring that we send the best-quality water to NYC at all times.
