jueves, 6 de agosto de 2015

A Billion Gallons a Day

It is the gold standard of urban water supplies. The New York City watershed was assembled during the 20th century, and the system’s underground aqueducts are considered an engineering marvel.

Self-study activity:
Watch this New York Times video and note down the main ideas about these topics:
- where New York's water comes from
- when and why the city decided to find sources of water somewhere else
- how the water is treated

The drop that comes out of your tap entered the water system in New York about three months earlier at a distant reservoir, 100 or so miles away from the city.
Making and operating infrastructure is key to the city to continue to have water. Without water the city doesn’t exist.
What is most incredible about New York City water supply is that it gets here by gravity, without any machines.  We have mountains, you know, that are a hundred miles away which are high enough to collect pure water and for it to be delivered to us entirely by gravity.
So the reservoir watershed area is roughly 2,000 square miles. Large area covers eight counties in New York State and a small sliver of Connecticut. The city system consists of 19 reservoirs and three control lakes, has 580 billion gallons of storage, serves 9.4 of million people in New York City and in Upstate counties.
There isn’t a lot of fresh water on the Island of Manhattan and there wasn’t very much even in the beginning, when the Dutch first settled at the southern tip of Manhattan in the mid-1600s.
But it was really fires that drove the system to find the source of reliable source of water.  There’s the Senecan fires in 1830s in Manhattan were truly led to the city looking upstate for the first time for supply. First place the city went to was the Crohen system and eventually the city continued to grow. There’s a need for additional water and began looking far and wide for additional sources of water.
New York City had to go to the main land to tap a true, abundant, fresh river and bring that river in an aqueduct to the city.
The challenges were that no such sort of thing had ever been built before in the United States, essentially about a 35-mile brick and masonry aqueduct that had to traverse rough terrain, had to go up and down valleys, had to be buried in some places.
And they would start with a crew of Irish labourers, chipping away at the stone, bang, bang, bang. You can imagine the muscles those guys had.
In the early 20th century two additional water supplies were added. The Catskill Aqueduct and the Delaware Aqueduct.
When the city came up to build the systems, eminent domains was used, people were forced off their farms and their communities, entire communities were evacuated, graves were relocated. There’s a lot of folks with deep roots in the Casco who remember this, remember the stories about it.
Everybody knows… to come up for about every day, you gotta be crazy sitting on a little row boat every day, and I told them, I said this is as close to… We’ve lived in the reservoir before there was a reservoir and I’ve lived right by it as if… for all my life. Gone I would like to have the old age back but let’s face it. We’ve got what we’ve got, we’ve got to enjoy what it is now. I mean, you look at it, never know there was a town under here.
From a Showcan reservoir enters the Catskill aqueduct and travels 92 miles down to New York City, making a stop in Catskill Reservoir on Westchester county. And that’s the last point the water reaches before receiving treatment. Water is chlorinated and then moved down to the Delaware aqueduct to the Catdell UV plant where it is treated with UV light.
One of the key components of our system or the key facts about our system is that is an unfiltered water supply. And because it’s unfiltered we have to ensure that we provide a certain level of watershed protection, and the primary responsibility of this laboratory is performing analysis for pathogens including crypto spurium giardia .
Some research late in the 1990s showed that UV light was actually effective against crypto spurium. And we went forward to the Catskill Delaware UV plant. The city’s invested about 1.7b dollars in watershed protection programmes and that’s a significant amount of money that the consumers in the city are paying for but it’s a lot less than the city would have paid to build the filtration plant. It also allows us to reduce how much of this chemical chlorine we use in the water since we now have this facility in service.
The next significant aqueduct we built was the Delaware aqueduct. In the late 1980s, early 1990s, there was leakage that was identified from 15m gallons a day to 35m gallons a day. Fixes is going to build a by-pass tunnel around the leaking section, so go underneath the Hudson, another cross in the Hudson river by-pass and the by-pass itself will be about 2.5 miles long.
The reservoir that is in front of you represents about 90 acres in the area and approximately 900m gallons of water, so in rough terms the volume of the reservoir is essentially one day’s supply or one day’s usage for the citizens of New York City. There are a lot of moving pieces to what we do and everybody sort of plays an instrument in the band of supplying water to the city.
I think it’s important for all New Yorkers to be aware of their water system, to not take for granted that that water that comes out of your tap so seemingly, so effortlessly. Many generations of workers have gone into creating this incredible water supply which is the gold standard for urban water supplies, copied by other cities around the world.