Impacts of Hurricane Sandy to NYCDEP WWTPs and Pump Stations. December 12, 2012

Transcription

1 Impacts of Hurricane Sandy to NYCDEP WWTPs and Pump Stations December 12, 2012

2 Presentation Agenda Overview of NYC Sewer System and Treatment Plants Preparations Made in Anticipation of Sandy Status of the WWTPs and Pump Stations During the Storm Overview of the Damages that DEP Sustained Lessons Learned 2

3 Overview of NYC Sewer System and Treatment Plants 14 WWTPs: Design Flow = 1.8 BGD Actual Flow = 1.2 BGD 4 CSO Retention Facilities Sewer system consists of: 3,330 miles of combined sewers 2,200 miles of sanitary sewers 1,800 miles of storm sewers 524 regulators 96 pump stations 3

4 Preparations Made in Anticipation of the Storm Established a 24-hr Incident Command Center, staffed by senior DEP managers, on Saturday, October 27. Plant and Collections Facilities personnel drilled on evacuation, sheltering-in-place, and power-down protocols. Prepositioned mobile hydraulic pumps and generators for quick deploy. Scheduled additional staff to work Oct 29/30. Stocked food and water. Prepped in-plant emergency generators for quick start on power loss. Topped off on chemicals and fuel. Reduced sludge inventory. Sandbagged and hardened key equipment at plants and pumping stations. Notified electrical and mechanical contractors to be on standby. Tested communication system using 800 mghz radios. Operations managers were stationed at key facilities on October 29. 4

5 Status of the WWTPs and Pump Stations During the Storm Several plants experienced significant flooding. The Rockaway plant was completely submerged. The Oakwood Beach plant became an island, as the surrounding community was inundated by storm surge. The Manhattan Pumping Station at East 13 th Street, which conveys approximately half of Newtown Creek s flow, was flooded. 51 pumping stations, most of which are in underground vaults, had interruptions due to flooding, power loss. 5

6 Status of WWTPs and Pump Stations After the Storm By October 31, 2012 (Day 2) DEP crews and contractors, working around the clock, restore major operations at all plants except Rockaway, which resumes pumping and primary treatment the following day. Extremely high flows continue at many facilities, as pump-outs of homes and businesses peak. The Coney Island plant had to pump at maximum rates until November 2 nd. Oakwood Beach plant employees, though surrounded by an 11-foot surge, continued operations on generator power, preventing more than 80 million gallons of sewage from backing up into homes. (This drainage area is separately sewered; there are no CSO relief points.) November 2, 2012 (Day 5) All but the Bayswater Pumping Station on Rockaway is back in operation. Many stations are operating on generator power or mobile hydraulic pumps, as utility power is still down in many areas. 6

7 RK WWTP It took more than two days to pump out basement areas of the plant. Flood waters from basement areas were pumped to the primary tanks. The sludge dock area also suffered damage from the surge. 7

8 CI WWTP Digester Building The digester building is located at Shellbank Creek. It suffered extensive damage to all electrical control panels. 8

9 CI WWTP Thickener Building The thickener building was heavily damaged by flood water (8 high) and the motors, pumps, and control panels were submerged. The equipment was not accessible due to the high remaining water level at walkway. The control panels for Thickener Pumps were inoperable, along with the control panels for the Grinders. 9

10 Manhattan Pumping Station Trident actuator controlling influent gate #2 was partially submerged by storm water and gate #2 was out of service The control panel for influent gate #2 was damaged by storm water. It has to be relocated to higher than ground level 10

11 The status of the WWTPs and Pump Stations during the storm Note: This estimate includes direst damage and long-term expenses. 11

12 Lessons Learned DEP s preparations generally worked well. No injuries and operations were restored fairly quickly considering the historic surge. Need to update design guidance for location of critical equipment above new FEMA 100-year flood elevations (anticipated to be +2.5 above current elevations). Sandbags had limited benefit. Many sandbags at pumping stations were stolen by local residents to protect their own properties. Assessing hardening such as water-proof hatches and inflatable barriers. Did not anticipate gasoline shortage and significant disruption to bridge, tunnel and subway systems. Getting employees to their assigned locations was an challenge. Getting deliveries to plants was difficult. Did not anticipate a utility power outage of 12 days in some areas. Evaluating mobile fueling systems for emergency generators deployed at pumping systems. 12