Incident at Cannonsville Dam shines light on NYC’s complex water supply system

The Cannonsville Dam, which protects a major New York City drinking water reservoir, is operational again after a construction project struck a pressurized aquifer below the dam.

The incident shines a spotlight on the enormous complexity of the city’s water supply system, and the scores of upstate communities who live in its shadow.

At full capacity, the Cannonsville reservoir holds almost 100 billion gallons of water.

The Department of Environmental Protection, which manages New York City’s water supply and related infrastructure, said in a statement Sunday that the decision to resume normal operations at the dam was made in consultation with federal engineers, and “comes after weeks of testing and around-the-clock monitoring that proved the dam is safe, stable and uncompromised by the cloudy seepage that began three weeks ago.”

In mid-July, initial drilling for a new hydro-electric facility at Cannonsville inadvertently tapped into an underground aquifer. “All drilling work ceased when the workers noticed the flow of turbid [soil-clouded] water coming from a rock embankment near the [dam’s] release chamber,” the City said in its statement.

DEP spokesman Adam Bosch told NYER that testing has confirmed that the water is being released underground about 50 yards below the dam, and that the dam’s integrity was never threatened.

Cannonsville dam
This aerial photo of the worksite below Cannonsville Dam shows the light-colored turbidity that has been coming from the rock embankment and drainage area below the dam. It also shows water being released through the West Delaware Release Chamber, and the drill rig that is digging relief wells to end the turbid discharge by giving the artesian groundwater a new flow path. For more information, visit Photo and text credit: NYC DEP

Bosch said that the hydro-electric project proposed for Cannonsville is now being re-assessed.

The proposed facility, in combination with two other City-run upstate hydro-electric projects, would have the exciting potential to make New York City’s water supply system “energy neutral.” This means that the electricity generated by the three projects would be comparable to the amount of energy required to manage and filter the City’s entire water supply.

Taking steps to protect residents living below the dam

The Cannonsville reservoir and dam are located outside the town of Deposit in western Delaware County. The reservoir holds 95.7 billion gallons at full capacity.

While New York City officials stated that there was no “imminent threat” to the safety of the dam during their investigation, they encouraged local officials, emergency responders and downstream residents to “familiarize themselves” with maps showing areas that would be flooded under a “worst-case-scenario breach.”

In other words, prepare for what would happen if the dam failed when the reservoir was 100 percent full.

And, taking no chances, the City began to drain water from the reservoir into the west branch of the Delaware River as it assessed whether there was any structural threat to the dam. The draining has been stopped and, as of yesterday, the reservoir was at almost 75 percent capacity.

Adam Bosch said that within the week the DEP will seal the construction bore holes that released the pressurized groundwater.

“Intensive monitoring” at Cannonsville will also continue, says the City. This includes 24-hour observations by on-site staff and surveillance cameras, daily engineering inspections, and near real-time monitoring of water quality and safety instruments inside the dam.

Cannonsville: 120 miles away but absolutely essential to NYC

Completed in 1964, the Cannonsville Reservoir was the last of 19 such reservoirs built as part of New York City’s massive drinking water supply system. The City provides more than one billion gallons of water daily to more than 9 million residents, including 70-plus upstate communities in Ulster, Orange, Putnam and Westchester counties.

The watershed area that drains into the Cannonsville Reservoir is 455 square miles, the largest drainage “basin” in the City’s system.

Drinking water from Cannonsville flows into the West Delaware Tunnel and then travels 44 miles to the upper end of the Rondout Reservoir. From there, it is carried in the 85-mile-long Delaware Aqueduct toward New York City.

nyc water supply system
Credit: NYC DEP

A little discussed link to fracking

The Cannonsville dam and reservoir have an interesting connection to the multi-year battle over whether to permit high-volume hydraulic fracturing in New York State.

The reservoir sits on the western edge of Delaware County, within a few miles of the Broome County line. As the debate over fracking raged, New York City officials pointed out that seismic fault lines run throughout the area, posing a potential threat to the City’s water supply infrastructure if they were disturbed.

And while the City was able to preemptively ban fracking within the New York counties that make up its watershed, it had no control over what was going to happen just over the county line in Broome- despite the presence of underground fault lines.

Indeed, Governor Cuomo openly considered allowing fracking in Broome County before the practice was banned statewide. And some local residents leased land to drilling companies for that purpose.

Historic frustration with New York City control

The Cannonsville reservoir was formed when New York City dammed the west branch of the Delaware River. The town of Cannonsville, for which the dam and reservoir are named, was flooded in the process.

west branch map
Map of Delaware County, NY, showing the west and east branches of the Delaware River. Also visible is the proximity of the Cannonsville Reservoir to the Broome County line.

Every day, the New York City DEP releases water from the reservoir into the west branch of the river. Because of concerns about the dam over the last two weeks, the DEP has been releasing three times the normal daily rate of 500 cubic feet of water per second.

City officials say they are now slowly bringing release levels back down to normal levels.

Water is released downstream from Cannonsville under the terms of a 1954 U.S. Supreme Court Decree. A “flow program” was agreed upon by New York City and the states of Delaware, New Jersey, New York and Pennsylvania.

But the City’s daily water releases are at times a source of controversy within communities along the west branch.

west branch of delaware
West branch of the Delaware River. Photo credit:

In a July 31st local TV news segment, some residents of Hancock, which is downstream from Cannonsville, charged that New York City is mis-managing the releases and threatening their local economy.

“We are absolutely done with the way you’ve [New York City] treated us,” said Theresa Allen, a business owner. She charged that cold water releases, especially critical for trout fishing and related tourism activity, dropped by 20 percent in April and May.

“This business, the land it sits on…means nothing if that river is not there and not managed properly,” added Matt Batschelet, who owns a fishing resort on the west branch of the Delaware.

In response, New York City DEP stresses that it has gone to great lengths to work in collaboration with communities that are impacted by the City’s water supply infrastructure and/or constrained by watershed land use regulations.

The City also points to ongoing efforts to support sustainable economic development in its upstate watershed. But Theresa Allen of Hancock notes that besides tourism, “we have no industry in this town anymore.”

What Hancock and other watershed communities do have, however, is proximity to something New York City needs more than anything else- high quality and abundant water.


Making a Difference in NYC! Rain Barrels Save Water & Alleviate Local Flooding

Can a plastic tub save New York City? The humble rain barrel has a lot to offer- helping residents cut their water bills, keeping raw sewage out of local waterways, and cutting the city’s water consumption.

Managing rainfall more effectively has become a growing focus for New York City. Earlier this month, the city’s Department of Environmental Protection and Council Member I. Daneek Miller distributed rain barrels to 200 homeowners in St. Albans, Queens.

The DEP has distributed more than 2,900 rain barrels free of charge since 2008. Participation in the program is by invitation only, says the City. “Rain Barrels will be distributed in an organized fashion by neighborhood over the next three years,” the DEP notes on its website.

The 60-gallon barrels collect water that residents can use for tasks like watering lawns and gardens and washing cars, which helps to lower water bills. The barrels connect directly to a property owner’s downspout in order to capture and store stormwater that falls on the rooftop.

2nd rain barrell
Rain barrel in action. Photo credit:

As simple as they are, rain barrels are a serious response to a growing problem. If the City’s scientists are correct, we will steadily see more rainfall -and more intense rainfall events- in the five boroughs. They report that between 1900 and 2011, precipitation in Central Park increased about .7 inches every decade.

Saving money, water and more

How much of a difference can re-using rainwater make for a New York City home or building owner? A lot, apparently.

Watering lawns and gardens can account for up to 40 percent of an average household’s water use during the summer months, says the City. Water rates in New York City have nearly tripled in the last 15 years, a terrific series by WNYC recently found.

But rain barrels are about more than helping to cut costs for building owners. Neighborhoods like St. Albans in Queens, and sections of Brooklyn and Staten Island, have been plagued by ongoing flooding because the City did not construct proper storm drainage systems when they were first developed.

southeast queens floods
Flooded street in Southeast Queens. Photo credit: Empowered Queens United in Action and Leadership

“My district [southeast Queens] has suffered tremendously from the effects of localized flooding caused by an insufficient drainage system,” observed Council Member Miller in a statement.

By using rain barrels, “local residents are doing their part to help ease flooding conditions and conserve this most precious natural resource,” Miller said.

Absorbing rainwater before it overwhelms local sewers

The barrels are also part of a broader strategy to reduce the amount of stormwater entering storm drains, thus overwhelming local sewers and treatment plants. When this happens, raw sewage must be released into local waterways via combined sewer overflow points.

Between 25 and 30 billion gallons of raw sewage and polluted stormwater are discharged annually from over four-hundred combined sewage overflows into New York City’s waterways.

The rain barrels being distributed in St. Albans will help to protect the health of Jamaica Bay, says the City, because a number of local combined sewer overflow points release raw sewage directly into the Bay.

jamaica bay wetalnds
The wetlands of Jamaica Bay seen from the air. New York City’s wetlands are critical for maintaining local biodiversity and can also help protect areas further inland from coastal flooding, but they are threatened by ongoing pollution releases. Photo credit: City Atlas

The DEP also distributed rain barrels this month to 200 Morris Park homeowners in the Bronx. Part of the objective, reiterated the DEP, is to limit combined sewer overflows into the Bronx River and Westchester Creek.

The rain barrel giveaway program is part of the City’s Green Infrastructure Plan that aims to capture stormwater before it can ever enter the sewer system. DEP says it will invest $2.4 billion in green infrastructure projects, such as bioswales on city streets, green roofs and rain gardens, as well as other “source controls”, such as rain barrels.

These investments will “significantly reduce combined sewer overflows” by 2030, says the City.

Green roofs also help to collect rainwater before it enters storm drains. Students at the Bronx Design & Construction Academy in the South Bronx collaborated with Columbia University to build a model “Green Roof Integrated Photovoltaic Canopy” on their school’s green roof. “Students were vital in the construction and continue to be deeply involved in the data collecting process.” Text and photo credit: The Green Schools Alliance

Cutting NYC’s water consumption by 5 percent

Collecting rain water has another goal too– New York City plans to reduce overall water consumption by five percent in advance of a massive drinking water infrastructure project.

The DEP has begun a project to repair leaks in the Delaware Aqueduct which supplies roughly half of the city’s daily drinking water. In order to complete these repairs to the Aqueduct, the tunnel must be temporarily shut down in 2022.

nyc water supply system
Map of New York City’s water supply system showing the Delaware Aqueduct which is to be closed for repairs in 2022. Credit: NYC DEP

New York City residents, along with hundreds of thousands of suburban residents, consume over a billion gallons of water per day from the City’s water supply system, which is piped from a series of upstate reservoirs north and west of the city.

Other measures taken by the City to cut water use will include

  • a $23 million High Efficiency Toilet Replacement Program in “select” residential properties (saving 10 million gallons of water daily);
  • the installation of activation buttons on spray showers at 400 playgrounds (saving 1.5 million gallons daily during the summer months); and
  • new, high efficiency fixtures in the bathrooms of 500 City schools (saving nearly 4 million gallons daily during the school year).

The private sector is also getting involved. The Hotel Association of New York City is partnering with DEP to reduce water use at some of its premier hotels by five percent annually. Will we eventually see rain barrels at the Plaza?

When Algae Attacks: Murky Answers on State Water Safety

** After publishing this post, NYER did receive a response from the NYS Department of Health regarding their testing and treatment policies around cyanotoxins. Please see the update at the bottom.

Toledo, you’re in good company.

The same toxic algae that tainted the water for 400,000 Ohio residents earlier this month is on the rise in New York, too. Blue-green algae blooms have killed pets (at least one dog on Long Island, and possibly another in Essex County), sickened humans, and even clouded the waters of the iconic lakes in both Central and Prospect Parks.

Consuming or even coming into contact with these waters can cause serious health effects for people, pets, and wildlife. And because climate change is expected to make these blooms more frequent, the safety of water supplies throughout the state may be affected.

Tainted By Toxins

Blue-green algae is the common name for a category of algae-like organisms known as cyanobacteria, which occur naturally in freshwater. At low concentrations, they are both harmless and invisible.

This is not recommended. Ohio Sea Grant
Putting your hand in blue-green algae is not recommended. Ohio Sea Grant

But when nutrient levels in the water—particularly phosphorus and nitrogen—soar and combine with hot temperatures, cyanobacteria undergo a population explosion. These “blooms” turn waters shocking shades of pea green, and even more troublesome, can produce harmful toxins called microcystins.

Exposure may cause fever, headaches, muscle and joint pain, blisters, stomach cramps, diarrhea, vomiting, mouth ulcers, and allergic reactions.

According to the Environmental Protection Agency, exposure to microcystins—through skin contact, consumption, or respiration—“may cause a wide range of symptoms in humans including fever, headaches, muscle and joint pain, blisters, stomach cramps, diarrhea, vomiting, mouth ulcers, and allergic reactions.”

High-level exposure can cause seizures, liver failure, respiratory arrest, and death. There is also evidence that long-term exposure may cause cancer.

“If you see it, avoid it,” advises the NYS Department of Environmental Conservation, the state’s lead environmental agency. That goes for pets and livestock as well.

A Statewide Situation

Since 2009, New York has been building one of the most robust algae monitoring programs in the country, thanks to a five-year, $750,000 federal grant to the Department of Health. The DEC website maintains a running list of active cyanotoxin notices (and an archive of past blooms), and enables the general public to report their own findings.

According to the NYS DEC, since 2012 “Harmful Algal Blooms” have been found in more than 140 recreation areas, reservoirs, lakes, and ponds in all parts of the state; 34 counties have reported blooms this year alone.

Counties shaded in green have had a suspicious or confirmed blue-green algal bloom in 2014.
Counties shaded in green have had a suspicious or confirmed blue-green algal bloom in 2014.

Given the transient nature of the blooms and the DEC’s inability to test every single body of water regularly, it’s likely that many other blue-green algae blooms have come and gone undocumented.

When grant funding for this program runs out in 2016, will the DEC be able to continue monitoring for algal outbreaks? Peter Constantakes, spokesperson for the NYS DEC says yes. “We will continue to seek funding for monitoring and outreach, [and we will] continue to partner with SUNY Stony Brook and other state agencies to gather data.”

Is NYS Water Safe?

As the situation in Ohio has shown, toxic algal blooms can do more than just look gnarly: large eruptions can disrupt entire cities and pose a significant threat to drinking water supplies. This vulnerability is due in large part to the fact that there are no agreed upon methods to test or treat drinking water for mycrocystin toxins.

According to the EPA, “no federal regulatory guidelines for cyanobacteria or their toxins in drinking water or recreational waters exist at this time in the United States.” And even if you can find the toxins, removing them is complicated.

“Drinking water operators must know the growth patterns and species of cyanobacteria that dominates the bloom, the properties of the cyanotoxins… and the most effective treatment process,” the EPA notes. Applying the wrong treatment process at the wrong time could actually release more toxins into the water source.

So, could the situation in Toledo play out in New York State? The answers are murky.

Algal bloom in Sodus Bay, in Wayne County, NY. Jay Ross/Save Our Sodus Association
Algal bloom in Sodus Bay, in Wayne County, NY. Jay Ross/Save Our Sodus Association

In the last two years, toxic blooms have been found in seven drinking water reservoirs, including the Tomhannock and Basic Creek which supply drinking water for thousands of people in Troy, Albany, and Rensselaer.

Repeated attempts over the last week to contact the DEC and the NYS Department of Health with regard to reservoir sampling, water treatment, and algal risks have been unsuccessful. The Albany and Rensselaer County Departments of Health have been equally hushed.

Toxic blooms have been found in seven New York State drinking water reservoirs.

From publicly available documents, it does not appear that the New York Department of Health has an official mycrocystin testing or removal protocol. The DOH website states that “public water supplies regularly test for a variety of man-made chemicals, naturally occurring contaminants, physical characteristics and microbial pathogens;” mycrocystins are not included on that list.

In general, it seems that reservoir testing for algal toxins happens on a case-by-case basis when blooms are observed. But without an official response from the DOH, one is left to wonder at the efficacy and safety of such an informal program.

**Please see below for an official response from the DOH.

Don’t Worry, NYC

By contrast, New York City is confident that algal blooms are not an issue. Adam Bosch, spokesperson for the NYC Department of Environmental Protection, assures New York City residents that there is no need to worry. “The answer is simple,” he states. “We just don’t have algae in New York City reservoirs.”

“NYC has a state-of-the-art watershed protection program that is targeted at preventing these kind of blooms,” Bosch continues. For the last 20 years, the DEP has worked to protect the forests and lands surrounding the reservoirs and rivers, replacing septic systems, developing a robust forestry program, and working with agricultural producers to reduce run-off.

NYC has a state-of-the-art watershed protection program that is targeted at preventing these kind of blooms.

“These healthy forests suck up all the extra nutrients and are so efficient that you don’t even find algal blooms in the headwaters,” Bosch said. Bill Wegner, staff scientist with Riverkeeper, confirms the DEP’s claims. “The water bodies have to be eutrophic, meaning nutrient-loaded [in order to have algae], and there are no eutrophic reservoirs that are part of the New York City water supply.”

And on the off chance that a bloom did develop? Weekly and monthly sampling of key points in the system means that New York City water is well-tested, some 550,000 times each year. And because the City’s water is pulled from a vast system of 19 reservoirs and three lakes, Bosch reassures that the DEP could switch one off easily without feeling an impact.

Behind the Blooms

Scientists point to a constellation of causes for the increase in blue-green algae blooms. Agricultural runoff (mostly fertilizer and manure), sediment erosion, flows from sewage treatment plants and septic tanks, and runoff from lawns all increase nutrient loads in our lakes and ponds.

And climate change is exacerbating the issue. The increased frequency of heavy rains and flash flooding are causing quick influxes of runoff into our water bodies, while higher summer temperatures create the ideal conditions for algal growth.

Algae bloom warning at Prospect Park. Photo credit: Emily Manley / NYER
Algae bloom warning at Prospect Park. Photo credit: Emily Manley / NYER

“Blooms are going to be longer and more intense,” says Hans Paerl, professor of marine and environmental sciences at the University of North Carolina. “It’s all part of the price we’re paying for climate change.”

Even when the blooms run out of fuel and die off, they can still cause trouble. As the algae sinks to the bottom, bacteria feasts on the decaying matter. This removes oxygen from the water, resulting in “dead zones” which cannot sustain any life.

The Bright Side

There is no doubt that toxic algae is a growing global concern. The EPA calls them a “major environmental problem in all 50 states” and a 2014 report by the National Wildlife Federation found that a majority of the states reporting blooms consider it a “serious” situation.

But, unlike many environmental issues, this is a problem with a relatively attainable solution. New York City’s protected watershed is a case in point.

Fixing the algal bloom explosion throughout New York State will require a significant reduction in the amount of phosphorous and nitrogen entering our water bodies. This means new guidelines for how farmers (and homeowners) apply fertilizer, better livestock management, and tighter control over sewage treatment plants (and combined sewage overflows).

Blue-green algal bloom in Lake Erie. Photo credit: National Oceanic and Atmospheric Administration

Federal action will be needed, too. This past May, Senator Chuck Schumer urged the EPA to issue guidance and recommendations to local water treatment plants on how best to test for and treat these cyanotoxins. He also pressed the EPA to develop water quality criteria for cyanotoxin levels in ambient water so that states like New York can better identify contaminated lakes and implement programs that will improve water quality.

**An Update From the NYS Department of Health

After publishing this post, NYER did receive a response from the NYS Department of Health regarding their testing and treatment policies around cyanotoxins.

Currently, the DOH tests drinking water for cyanotoxins “on a case-by-case basis,” if there is a report from the DEC of a bloom in close proximity to water intake pipes. Factors that may impact this decision include “size and extent of the bloom relative to the drinking water intake, toxin levels in the bloom, depth of the drinking water intake, duration of the bloom, [and] treatment at the water system.”

Those water samples are analyzed through a partnership with SUNY ESF, and if toxins are found, the DOH will provide guidance to water treatment plant operators and issue a public notification. In general, the DOH feels that conventional drinking water treatment, “consisting of flocculation, coagulation, sedimentation and filtration” is effective at removing any harmful algal cells. However, if the toxins have dissolved into the water, as was the case in Toledo, “additional treatment consisting of activated carbon filtration and/or advanced oxidative processes may be needed. “

A spokesman from the DOH reiterates our earlier point that “there are currently no state or federal drinking water standards or guidance values for cyanotoxins.”

The DOH confirms that the blooms that occurred in the Basic and Tomhannock reservoirs last year did not have any impact on drinking water delivered to consumers. Basic Creek Reservoir is a “back-up source” and not a primary water supply, while the bloom in the Tomhannock was “very localized and away from the drinking water intake.”


Testing Yields Good News on NYC’s Water

One of New York City’s most valuable assets -our drinking water supply- continues to serve us well. Drinking water quality “remains high,” the City said last month, and meets all health-related State and federal standards.

New York City’s water supply system provides about a billion gallons of drinking water daily to over nine million metro-area residents and visitors. And our water takes a long journey before it reaches our faucets, coming from reservoirs as far as 125 miles to the north.

In 2013, the city’s Department of Environmental Protection collected over 30,000 samples from its water distribution system and 17,000 samples from upstate reservoir watersheds. The City tests for a “broad spectrum of microbiological, chemical, and physical measures of quality.”

The results of tens of thousands of water quality tests conducted last year were summarized in a recent DEP report.

The City says it monitors continuously for certain “water quality parameters” –such as evidence of microscopic pathogens- as water enters the distribution system. And DEP regularly tests water quality at nearly 1,000 water quality sampling stations throughout New York City.

According to the DEP, of all the substances that were detected in the city’s water supply, none were at levels that exceeded State or federal standards. For instance, traces of chloride, from road salt, and nitrate, caused by runoff from fertilizer use and leaching from septic tanks, were found in some samples.

What else was picked up in the City’s tests?

Relatively low levels of aluminum, barium and chromium, which are caused by erosion; iron and sulfate, which are naturally occurring; fluoride and chlorine, which the City adds for public health purposes; and coliform bacteria, also naturally occurring.

The City tested for -but could not find evidence of- a number of organic compounds, such as benzene and toluene, which are hazardous to human health. Benzene and toluene, known human carcinogens, can be released into the environment through activities like gas and oil drilling.

While most New Yorkers expect consistently high-quality and safe drinking water, our water supply is unique, both in terms of purity and volume. Most of the city’s water supply is unfiltered, coming from upstate reservoirs fed by mountain streams. It is one of the largest unfiltered municipal water supply systems on the planet.

New York City’s water supply network has three major components, the Catskill, Delaware and Croton watersheds. The city drew only from the Catskill and Delaware systems in 2013, both of which are unfiltered.

The Croton watershed, located in Westchester and Putnam counties, much more densely populated areas and closer to pollution sources, now requires additional filtration. Under a Consent Decree between New York City, the State, and the federal government, the City is constructing a multi-billion dollar filtration plant for Croton water.

While the massive facility under construction in the Bronx’ Van Cortlandt Park is nearing completion, the City noted that it had “missed several milestones in the Consent Decree”.

But the City has recently opened an ultraviolet water treatment facility, the world’s largest, it says. The facility serves the Catskill and Delaware systems, providing treatment for Cryptosporidium and Giardia, “naturally occurring microorganisms that can be found in surface waters and can cause gastrointestinal ailments in humans”.

Preparations Continue for Closure of Tunnel Supplying Half of City’s Drinking Water

You may not feel it, but major developments are afoot in the city’s water supply.

New York City is preparing to close down a massive—and leaking—aqueduct which delivers over half of the city’s drinking water from upstate reservoirs, more than 120 miles to the north.

The billion-dollar, multi-year repair work on the Delaware Aqueduct is the “central component” of the city’s Water for the Future program, which “aims to ensure clean, safe and reliable drinking water for future generations of New Yorkers.”

On Friday, the city announced that blasting had begun in Wappinger, N.Y., on the Dutchess County side of a new tunnel that will permanently bypass a leaking section of the aqueduct.

The 85-mile long Delaware Aqueduct conveys drinking water from four major reservoirs in the Catskill Mountains -Cannonsville, Neversink, Pepacton and Rondout- to the city’s water distribution system.

The city says that, on average, the Delaware Aqueduct provides more than half of the approximately 1 billion gallons of drinking water consumed by New Yorkers every day. The aqueduct, reportedly the world’s longest continuous tunnel, was constructed between 1939 and 1944 and crosses Ulster, Orange, Dutchess, Putnam and Westchester counties.

New York City’s water supply system is used by more than 9 million people, including 8.4 million in the five boroughs, along with residents of Ulster, Orange, Putnam, and Westchester counties.

City water comes from the Catskill, Delaware, and Croton watersheds.

Leaking Millions of Gallons Per Day

The Department of Environmental Protection, which manages the water supply system, has been monitoring two leaks in the Delaware Aqueduct since the 1990s. The leaks—located in Newburgh and Wawarsing—release a combined 15-35 million gallons a day, “depending on the rate of flow inside the aqueduct.”

To address the leaks, DEP has begun construction of a 2.5-mile bypass tunnel that will run 600 feet below the Hudson River, from Newburgh to Wappinger. The bypass tunnel, which is scheduled for completion in 2021, will convey water around the leaking portion of the Delaware Aqueduct in Newburgh.

DEP spokesman Adam Bosch told NYER that the aqueduct would be shut down for about eight months in 2021, in order to drain it and connect it to the bypass.

What Will Happen When the Delaware Aqueduct is Closed?

Delaware Aqueduct bird’s-eye view. Click here for a larger version.
Delaware Aqueduct bird’s-eye view. Click here for a larger version.

The city says that it has developed a “portfolio” of projects that “will ensure New York City has high-quality and reliable drinking water while the aqueduct is out of service.” This portfolio includes rehabilitating water supply sources used by the city in the past.

The 74-mile-long Catskill Aqueduct, which delivers water from the upstate Ashokan and Schoharie reservoirs, will undergo a repair and rehabilitation project starting in 2016.

The city plans to increase the tunnel’s capacity by approximately 30-40 million gallons of water each day.

For additional water supplies, DEP will also rehabilitate the Queens Groundwater System, formerly the Jamaica Water Supply, which will “sustainably provide more than 33 million gallons of water a day in southeast Queens”.

Groundwater in Queens? Is it safe to drink?

DEP has “committed to using proven technologies to ensure these wells produce high-quality water that meets or exceeds all water quality standards”. The Queens Groundwater System consists of 68 wells at 48 separate well stations.

Another highly complex and expensive project, the new Croton Water Filtration Plant, is entering its final stage of construction in the north Bronx. The city says testing of the filtration system and water lines is nearly complete.

Once online, the filtration plant will allow New York City to again use water from reservoirs in Putnam and Westchester counties that are part of the Croton System. DEP says this will provide nearly 300 million gallons of “high-quality” water each day.

And New Yorkers will have to start thinking more seriously about water conservation.

Between now and the shutdown of the Delaware Aqueduct in 2021, DEP will implement several initiatives to reduce water consumption in the city by as much as 50 million gallons a day.

Water conservation tools –like activation buttons on spray showers- will be rolled out in city parks and public schools. The city is also developing incentives to encourage water conservation in private homes and hotels.

Cool Photos of the Just Rehabbed 123-Year-Old New Croton Aqueduct

New York City has released photos today of this critical—and historic—piece of our water supply infrastructure.

The city also provided some great detail on why the New Croton Aqueduct is so significant. The Department of Environmental Protection says that the $177 million rehab project is a “key milestone towards reactivation of the Croton Water Supply System, which can provide between 10 and 30 percent of the city’s daily water needs.”

More Information from the City’s Release:

The Aqueduct was originally placed into service in 1890 and is a 33-mile-long, 13-foot-diameter, brick-lined tunnel that was engineered to convey by gravity up to 290 million gallons of drinking water each day from the New Croton Reservoir in Westchester County to Jerome Park Reservoir in the Bronx.

The Aqueduct begins just below ground level and reaches a depth of roughly 400 feet.

The New Croton Aqueduct conveys water from the City’s oldest collection of upstate reservoirs in Westchester and Putnam Counties, the Croton watershed, to the in-city drinking water distribution network. For more than 150 years the system provided unfiltered drinking water to the city, first through the Old Croton Aqueduct, which was built in 1842, and then the New Croton Aqueduct.

However, as population density increased around the Croton reservoirs, water quality in the system diminished and, in the late 1990s, DEP stopped using Croton Water for in-city distribution and began planning the construction of a filtration plant. With the system taken off-line and the Aqueduct drained of water, DEP conducted an extensive inspection of the tunnel and began plans for repairs.

Water for New Yorkers of the Future

A major component of the project was the connection of the Aqueduct to the Croton Water Filtration Plant in the Bronx.

A large concrete plug, 58 feet long and 12 feet wide, was built within the Aqueduct to direct the water through a new tunnel to the filtration plant. Once the water has gone through the filtration process, it travels through a separate tunnel back to the Aqueduct, downstream of the concrete plug, and towards the distribution network. The filtration and mechanical systems within the Croton Plant are currently being tested with water provided through the New Croton Aqueduct.

The completion of the Croton Filtration Plant and the reactivation of the Croton drinking water supply system will play important roles in the future as DEP repairs leaks in the Delaware Aqueduct, which currently supplies more than 50 percent of the city’s daily water needs.

Last year DEP began building two vertical shafts on opposite sides of the Hudson River in Orange and Ulster Counties. The shafts will be used by workers to build a bypass tunnel around a leaking portion of the Delaware Aqueduct, roughly 600 feet below ground level. Once that bypass tunnel has been built, DEP will temporarily shut down the Delaware Aqueduct in 2021 to make the necessary connections.

The Croton system will be critical in ensuring that DEP can continue to meet the city’s drinking water needs during the shutdown of the Delaware Aqueduct. It will also help to supplement the city’s water supply during future drought conditions.

DEP manages New York City’s water supply, providing more than one billion gallons of water each day to more than nine million residents, including more than eight million in New York City.

The water is delivered from a watershed that extends more than 125 miles from the city, comprising 19 reservoirs and three controlled lakes. Approximately 7,000 miles of water mains, tunnels and aqueducts bring water to homes and businesses throughout the five boroughs.

And for all you New York City water system fanatics, here are some details on the actual work on the aqueduct:

Rehabilitation work included re-grouting the brick lining of the tunnel, upgrading 34 shaft site connections that allow crews to access the tunnel from ground level, and repairing valves and pumps that allow certain Westchester communities to pull water from the Aqueduct.

Five historic gatehouses located at ground level along the route of the Aqueduct were also restored.

Due to a limited number of access points, and restrictions on the size of the equipment that would fit through them, much of the machinery was taken apart and lowered by crane though the shafts hundreds of feet down to the Aqueduct, where it was reassembled.

The inspection of the Aqueduct began in 1996 and included the use of ultrasonic stress waves, ground penetrating radar, and diamond core test drilling to determine the permeability and strength of the tunnel lining and surrounding bedrock. A remotely operated vehicle inspected the portion of the tunnel that runs under the Harlem River, which was not dewatered.

Overall, the Aqueduct was found to be in good condition, with some areas requiring sediment removal, the repair of cracks in the tunnel lining, and brick and mortar repointing and replacement.

Rehabilitation work commenced in 2004 and was completed in 2013. The interior of the Aqueduct was power washed and where investigations showed that a void may be present behind the tunnel lining, a series of grouting injections was made to ensure the stability of the tunnel.

The lining of the tunnel is made up of more than 163 million bricks and portions were repointed and secured with new grouting to reduce friction in the tunnel and keep groundwater from seeping in. Additionally, a new 10-foot diameter shaft cap was installed at the Aqueduct’s terminus in upper Manhattan.

Work also included the upgrade of existing connections to the Aqueduct, including shafts and pumps, for the Villages of Briarcliff Manor, Tarrytown, and Sleepy Hollow. The New Croton Aqueduct serves as a backup water supply for these villages, which primarily rely on the Catskill Aqueduct.

In addition, the towns of New Castle, Ossining, and Pelham, the villages of Pleasantville, Ossining, Irvington, Ardsley, Bronxville, Dobbs Ferry, Hastings-on-Hudson, Pelham Manor, Pelham, Tuckahoe, and the City of New Rochelle also have connections that allow them to use water provided through the New Croton Aqueduct.

How Are We Doing? City Reports Back on Protecting Drinking Water & Fighting Pollution

New York City air pollution levels are lower than they have been in over fifty years. New York Harbor is the cleanest it’s been in a century.

So says the city’s Department of Environmental Protection, which released its 2013 progress report earlier this month. The city attributes improvements in the Harbor’s water quality to major investments in wastewater treatment. And enhanced air quality is “largely” due to the phasing out of heavy heating oils.

“This dramatic reduction in [air] pollution has prevented 800 deaths, and 2000 emergency room visits and hospitalizations from heart and lung diseases each year compared to 2008,” said the city’s report.

In addition to maintaining the daily water supply for nine million city and suburban residents, DEP’s almost 6,000 employees are responsible for collecting and treating the 1.3 billion gallons of wastewater produced daily by New York homes, schools and businesses; and reducing air, noise, and hazardous materials pollution.

The To-Do List

The city’s environmental “to-do” list, as laid out in the DEP’s 2011-14 strategic plan, includes one-hundred specific objectives ranging from: “restore wetlands habitat in and around Jamaica Bay” to “develop a leak detection system for [water] customers” to “protect the water supply from hydrofracking for natural gas in the New York City watershed”.

[While the DEP opposes hydraulic fracturing in the city’s vast upstate watershed, it notes that it helped to facilitate approval for the first natural gas pipeline projects to be built within the five boroughs in decades, the Spectra (cross-Hudson) and Rockaway pipelines.]

The DEP, led by Bloomberg-appointed Commissioner Carter Strickland, says eighty-five of its strategic objectives have been accomplished. “Considerable progress” has been made toward making the agency “the safest, most efficient, cost-effective, and transparent water utility in the nation.”

Hello Tunnel No. 3

According to Strickland, one of the agency’s “notable” accomplishments in 2013 was the activation of the Manhattan leg of City Water Tunnel No. 3.

There is an urgency to the work on Tunnel No. 3, the largest infrastructure project in the city’s history. The new tunnel is needed in order to provide “critical redundancy” to the city’s water supply, especially while the city inspects and repairs Tunnel No. 1.

The city has also moved ahead with a $1.7 billion program to repair the Delaware Aqueduct, which delivers water to New York City from the western section of the city’s watershed. The aqueduct is reportedly leaking between 15 and 35 million gallons per day, and has been cited as an example of the aging of the city’s water supply infrastructure.

The DEP also reported a ground breaking on a separate $21.2 million project to connect the Catskill and Delaware aqueducts, which are the two main water supply lines to the city.

And in 2013 the city opened an Ultraviolet Disinfection Facility in Westchester County to treat potentially harmful organisms in the city’s water supply without the use of chemicals. The city says that the $1.2 billion facility is the largest of its kind in the world, and that it “ensures that New Yorkers continue to enjoy the highest quality drinking water in the nation”.

The DEP also focused on local water quality and sustainability projects, including the rehabilitation of the 1.3 mile Gowanus Canal Flushing Tunnel in order to bring oxygen-rich water from New York Harbor into the Canal.

Among the projects yet to be completed? The massive Croton water filtration plant in the Bronx’ Van Cortlandt Park. The city says it will be done this year.

The Challenges Ahead

But some argue that the city has a long way to go in managing its water supply and other environmental infrastructure.

“We are at a crossroads,” says Paul Gallay, president of Hudson Riverkeeper, a non-profit which monitors both the metro-area’s water supply and the Hudson River and its tributaries. “A lot of money has been invested in the water supply system but there are threats that need careful attention.”

Gallay said that both lead in pipes and the volume of pharmaceutical products in the water supply deserve more scrutiny.

And Gallay stressed that the city needs to “ramp-up” how it deals with stormwater. The state agrees, saying that a wastewater infrastructure “crisis” is in the making throughout New York.

Currently, Gallay explained, anything more than a half-inch of rain overwhelms the city’s sewers, which are then opened into local waterways. “Every year, old sewers flooded by stormwater release more than 27 billion gallons of untreated sewage into the New York Harbor alone” notes the state Department of Environmental Conservation on its website.

What’s the answer? The state says that millions of dollars in lost federal Clean Water Act funding must be restored. Gallay added that the city and state have agreed to start thinking outside the box about how to handle stormwater, but it needs to happen more quickly.

Stormwater, he argued, should be “used as a resource that can cool the city.” Gallay said that green infrastructure solutions like rooftop gardens and permeable pavement can both absorb water and lower urban heat levels.

Upstate and Downstate

But of particular concern to Riverkeeper is New York City’s relationship with upstate watershed communities. The city has to periodically release excess water from its upstate reservoirs into nearby streams and creeks, which local elected officials have said degrades water quality.

On January 9th, the city announced that it had begun to release “high-quality” water from the Ashokan Reservoir in the Catskills in order to remain within the 90-percent storage limit required by state regulators, and “to further reduce the potential for flooding during the late winter and spring”.

The DEP said that it planned to reach a release rate of 300 million gallons per day.

Previous discharges into the lower Esopus [Creek] have created “terrible problems with turbidity…[the Esopus is] full of mud from the city’s reservoirs,” said Gallay.

News reports in the upstate Daily Freeman said that current releases come “while there is a low turbidity level in the west basin [of the reservoir]”. Nonetheless, “among complaints from property owners…has been the strength of water releases [which] has eroded stream banks and increased downstream flooding,” wrote William Kemble in a January 9th Daily Freeman article.

The city, maintained Gallay, cannot provide water to its residents on “the backs” of upstate residents.

Will the de Blasio administration work with upstate communities to address their concerns about the city’s management of its massive watershed? “I’m confident that they’ll be responsive,” said Gallay.

New York City Constructs World’s Largest Ultra-Violet Water Treatment Facility

Last month, the City announced the completion of a $1.5 billion Westchester facility that will treat New York City’s water supply with ultraviolet light. The City says that it is the largest such facility in the world.

According to the City’s Department of Environmental Protection, the facility “will provide an added layer of protection against pathogens and other harmful microorganisms for the drinking water consumed by…residents of New York City and portions of Westchester County.” The 270,000 square-foot facility is designed to treat more than 2 billion gallons of water each day.

The new facility will provide treatment for Cryptosporidium and Giardia, “naturally occurring microorganisms that can be found in surface waters and can cause gastrointestinal ailments in humans,” according to a DEP press release. Both organisms are naturally occurring but are found at only very low levels in New York City’s water supply, the DEP added.

Nonetheless, the agency said that new federal regulations for treating drinking water were created due to the fact that Cryptosporidium is resistant to disinfection with chlorine.

The DEP described the technology at the new facility as “revolutionary”. As drinking water passes through the facility, it is exposed to ultraviolet light that “destroys the genetic code of the microorganisms, rendering them unable to reproduce or cause infection.” The DEP noted that researchers -with funding from the city of New York- discovered that exposing water to low levels of ultraviolet light was effective at rendering Cryptosporidium and Giardia harmless to humans in the late 1990’s.

New York City has one of the largest, predominantly unfiltered municipal water supply systems on the planet. The system, stretching across 125 miles, relies on mountain water flowing into upstate reservoirs, which is delivered to the city through a network of tunnels and aqueducts.

The system delivers over one billion gallons of drinking water to nine million people in New York City and Westchester County every day.

In an April interview with the Gotham Gazette, water supply expert David Soll said that the City was building the ultraviolet facility “so they don’t have to use as much chlorine to get rid of bacteria.”

New York actually has three water supply systems: the Croton, Catskill and Delaware systems. The Catskill and Delaware systems are “very interlinked” and supply ninety-percent of New York City’s drinking water. That water is not filtered because “the natural landscape acts as a filter,” said Soll.

Soll added, “because Catskill and Delaware water is coming from a place that is not very densely populated, with relatively little industry, the city could take watershed protection measures to ensure that it could still meet the health standards.”

Soll explained that, in addition to the ultraviolet facility, the City of New York is also building a massive water filtration plant in the Bronx as ordered by the federal government. “There was no way New York could comply with safety standards for water coming from the Croton region. There’s too much development. That’s why they are required [by the federal government in 1993] to build the plant,” he said.

The Bronx plant—which would filter about 10% of the city’s water supply and is located in Van Cortlandt Park—is very close to completion said a DEP spokesman.

To learn more about the ultraviolet facility, read the City’s October 9th press release.


The Future Of New York City’s Water

This is part 2 of a 2 part interview. Read the first part here.

Even after decades of commercial and residential development in upstate New York, the city’s mostly unfiltered drinking water is renowned for its purity. The water system will face increasing challenges — from growing demand to aging infrastructure to the possibility of gas drilling in neighboring counties — in the years ahead.

In the second part of Gotham Gazette’s exclusive interview with historian David Soll, the author of the newly released book Empire of Water (Cornell University Press) discusses the current and future challenges facing the city’s water supply system, which delivers over one billion gallons of fresh drinking water to nine million people each day.

[Read more at Gotham Gazette]

City’s Longest-Running Construction Project Reaches Milestone Ahead of Schedule

Construction on what has been described as New York City’s longest-running and most expensive construction project — a tunnel to expand the capacity of the water supply system — reached a new milestone yesterday. And it was ahead of schedule.

Work on Manhattan sections of the tunnel have been taking place seven days-a-week — on multiple shifts.

The project is one arm of the extensive network of tunnels, aqueducts and reservoirs that comprise the city’s remarkable water supply system.

Approximately 2,750 feet of new trunk water mains have been installed on the Upper East Side, along with upgrades to existing mains. The work was executed by the city’s departments of Environmental Protection and Design and Construction, who report that the $38 million construction project was completed five months early.

[Read more at Gotham Gazette]