All stations sampled (except exploratory site at Castle Oil at border of Tarrytown and Sleepy Hollow) are regular Riverkeeper monthly sampling locations.
If you look at our historical data at these sample sites you’ll see that contamination is often present and significant – when there is NOT a sewer main break. Chronic wet weather discharges are the real problem, not the accidents.
Yonkers inshore at mouth of Saw Mill (one discharge was in Saw Mill): sampled at 1410, Entero MPN 10/100ml, flooding
Irvington at Boat Club beach: sampled at 1505, Entero MPN <10/100ml, flooding
Tappan Zee mid channel: sampled at 1555, Entero MPN <10/100ml, flooding
Tarrytown Marina (one discharge was in Andre Brook, off Marina): sampled at 1610, Entero MPN >24,200, high tide, smelly, discolored grey, brown water
Castle Oil terminal (one discharge near kayak launch here): sampled at 1725, Entero MPN 84/100ml, high tide, now odor or discoloration.
Ossining moorings and beach: sampled at 1810, Entero MPN <10/100ml, end of flood.
EPA guideline: Over 104 Entero/100ml is “unacceptable” for swimming and primary contact
The estimated volume of the Westchester discharge was approx. 3 million gallon/day – it flowed about 29 hours / approx. 3.4 million gallons
For contrast, NYC discharges 28 BILLION gallons from CSOs annually – combined rain water and sewage.
About 20% of that is sewage – so 5.6 billion gallons is the sewage component.
Assuming 50 CSO events per year we get an average 112 million gallons of SEWAGE per CSO event – some more, some less.
So this Westchester release was minor compared with the chronic releases in NYC and elsewhere during rain events.
Regarding the Ironman Triathlon, I think the swimmers probably lucked out. Although it rain hard on Friday it did not rain all that long and then the rain held off overnight. My guess is that they had acceptable WQ Saturday morning. I was tempted to go early and sample but didn’t because IF the WQ had been bad we would have appeared to be real spoilers publicizing it after the fact. I want to address this issue without beating up on people.
And of course next year NYC will have to notify when CSOs deploy because RIVERKEEPER GOT THE “SEWAGE RIGHT TO KNOW ACT PASSED!
|Saw Mill river entering Hudson at Yonkers. Sewage discharge was into Saw Mill a short distance inland|
Beach at Irvington Boat Club
|A guy crabbing right at the entrance to Tarrytown Marina. He didn’t want to hear about a sewage spill.|
Cloudy surface layer in Tarrytown Marina
Andre Brook empties into Tarrytown Marina. There is a CSO or Bypass in Andre Brook
SPDES sign at discharge point in Andre Brook
Castle Oil / kayak launch. Chlorine tanker visible inland. Health Department was chlorinating this outfall.