How the Department of Environmental Protection looks after New York City’s water supply

Established more than 100 years ago, the New York City Department of Environmental Protection (DEP) and its police division are tasked with managing and protecting New York City’s water supply. About 200 officers patrol the water system and its surrounding lands 24 hours a day in traditional patrol cars, as well as boats, bicycles and even helicopters.

DEP’s effort to monitor the water supply from the air began slowly in the late 1990s. In 1998, DEP police began to fly over the reservoirs, dams and aqueducts about once a week with the help from local members of the Civil Air Patrol, a federally supported cadre of volunteers who tackle a range of missions related to aviation. DEP supported the volunteers in 1999 by leasing a helicopter for an additional handful of flights each year. 

After the 9/11 terrorist attacks, DEP leased a helicopter of its own, a Bell 206 JetRanger, and began daily patrols from the air with contract pilots and sworn police officers as tactical flight officers (TFOs). The aviation mission was upgraded from a part-time section within the DEP police to a full-time aviation unit that took flight every day and monitored an area slightly larger than the state of Delaware.

“We now operate from the Hudson Valley Regional Airport in Dutchess County, and our jurisdiction covers 2,500 square miles [6,475 square kilometers],” said Lieutenant Randall Hurlbert, the aviation unit commander. “About 75% of that land is covered by dense forests, but villages, farms and outdoor tourism destinations are also found.” 

Flying from the southern tip of Manhattan to the northern tip of the jurisdiction might take 1.5 hours in total, with large properties, aqueducts, infrastructures, and bodies of water to protect outside New York City.

In the years that followed the introduction of the Bell 206, DEP found that its aviation unit helped in many ways. The helicopter was used to assess damage and rescue stranded residents after powerful floods ravaged parts of the Hudson River Valley and Catskill Mountains, two areas to the north of New York City where its reservoirs are located. It has been used to patrol the reservoirs to determine the extent of fuel spills, major turbidity events, and debris fields from plane crashes.

The aviation unit now operates two single-engine Leonardo AW119Kx helicopters. The first was purchased in 2018 and the second four years later. 

“The division also considered the Bell 407 and the Airbus AStar,” Hurlbert said. “Leonardo was selected based on an extensive bid process and they met the specs that were outlined in it.” 

The two helicopters are known as AIR 6-1 and AIR 6-2. They have a range of 592 miles (954 kilometers) with a cruising speed of about 135 knots (250 kilometers per hour), and enough space for two crewmembers and six passengers.

The unit runs with only seven people: its commander, one sworn police pilot, one sergeant who currently has a student pilot certificate, two civilian pilots, and two certified civilian airframe and powerplant mechanics. The goal is to have three certified mechanics for the unit. The helicopters usually fly with a pilot and TFO operating the systems. 

“Our normal configuration is set up to fly with three, with a crew chief, but we routinely fly patrols with just a pilot and TFO,” said detective Scott Hogan, one of the two sworn pilots. 

Nearly all the maintenance is done in-house. Leonardo’s assembly line and maintenance hub is in Philadelphia, a one-hour flight from the Hudson Valley Regional Airport, and the aircraft can easily be flown there for warranty-type work.

As a police department, the aviation unit remains on alert 24/7. When not engaged in scheduled missions, the unit does active patrol and remains on-call if a need arises. 

“We work very closely with emergency teams and of course our patrol division on the ground. If they have any needs, we will assist them,” Hurlbert said. “And we have been called to assist other agencies in the area that don’t have helicopters for larger scale law enforcement events.”

The day-to-day activity consists of patrolling the aqueducts and reservoirs and looking for anomalies. The AW119Kx’s never exceed speed (VNE) is 152 kt (282 km/h), but most of the time the patrols are flown at 80 to 90 kt (148 to 167 km/h), 500 feet (152 meters) above the ground when it comes to aqueduct surveillance. 

“We check things like storm damage, rivers or creeks flowing into reservoirs that could be experiencing turbidity — a condition that occurs after storm events that can cause water to turn brown,” Hogan said. “We also have a large amount of activity on the reservoirs like hunters, people going hiking, fishermen … We could be potentially called to assist or overwatch.” 

Nearly 90% of the flights take place north of New York, outside the Big Apple. 

“All city agencies report to the mayor. NYC DEP police and NYPD [New York Police Department] work together at many levels since our jurisdictions overlap,” Hurlbert said. “We don’t generally operate in the city on a regular basis and we don’t get involved in New York City a lot. Once or twice a month, we go down to do a flight around the city so we can stay familiar with the airspace and check our infrastructure there. When you look at the state of New York and the area in which we patrol, New York City is a very small subside.”

The unit also provides some fast and easy transport to the DEP biologists. The story goes that by the 1970s, bald eagles were almost extinct in New York because their food source was contaminated by the pesticide DDT. After the pesticide was banned, lawmakers and biologists undertook a significant effort to protect the few eagles that remained and boost their chances of survival. 

DEP biologists now board the helicopter for the biannual eagle count from the air. Over the course of two days in 2020, DEP police helped their colleagues find and document 71 bald eagles flying across parts of the water supply system. A high-definition video camera was used on AIR-6 to record a golden eagle, an extremely rare sight in this remote part of New York. The team flew hundreds of miles inspecting close to 100 nests to provide one of the most comprehensive surveys of American bald eagles in the county.

_{The right technology for the job} 

The helicopter’s computer includes a moving map system that allows officers to see many layers of information, including streets and topography. If an officer types an address into the mapping system, the screen will provide a flight line to follow and an arrival estimate for the current flying speed. The map also includes a “fire mapping” function, which can also be used to delineate spills, algal blooms, or suspended sediment in a reservoir. That allows a user to plot an outline of the affected area and calculate the size of the impact. 

This powerful mapping system was further enhanced by data from DEP’s geographic information system (GIS), which was loaded into the helicopter’s computer. This unique dataset includes high-definition topography, the exact locations of streams and wetlands, precise information on every reservoir, dam and aqueduct, and the boundaries of every parcel of water supply land owned by DEP. This detailed GIS information is generally used by scientists and engineers to develop and assess water quality protection projects throughout the region that surrounds the reservoirs. But it has also helped police patrol more efficiently by having quick and accurate access in the helicopter to the location of all the city’s water supply assets. 

AIR-6 helicopters are also equipped with a TrakkaBeam A800 with filters in its spotlight, capable of slaving with the camera system — a FLIR Star SAFIRE 380-HDc for videos and still images. This can help the police track potential criminals or identify environmental threats. 

In 2018, DEP scientists found very low levels of fecal bacteria in a stream that feeds one of its most important reservoirs. This particular stream was surrounded by a residential neighborhood connected to a municipal sewer system. Scientists tried to trace the fecal bacteria back to a particular home or a particular pipe, but their work did not yield success until they used infrared technology on the DEP police helicopter. 

During the following winter, AIR 6-1 flew over the neighborhood and scanned the ground with its infrared equipment.. A sewage leak will show up clearly on infrared because the leak will be significantly warmer than the cold winter ground. The FLIR easily identified the location of the leak, and it was quickly fixed. 

The helicopter is also outfitted with a cargo hook, a Bambi Bucket for fighting wildfires, and a loudspeaker.

“As far as I know, all law enforcement units in the area use the Bambi Bucket,” Hogan said. 

The unit has been very busy in the past months integrating a second helicopter in its daily operation, and training with external load operations. 

“The aircraft is set up, but we are at the beginning stages,” Hogan said. 

The helicopters are not instrument flight rules (IFR)-certified. However, they are night vision goggle (NVG)-capable and the crew make good use of this capability. 

“We have an internal program to train on NVGs,” Hogan said. “We follow federal regulations set up by the FAA [Federal Aviation Administration] for currency, with a certain number of takeoffs, landings, and time flying. Flying VFR [visual flight rules] at night with the ‘tubes,’ it’s almost like in the day.” 

The aviation unit flies 50 hours a month, or 600 hours a year, with its two helicopters. According to Hurlbert, it’s still too early to discuss acquiring a third bird. 

“It’s years away and it’s unlikely, just based on the cost. But we don’t rule anything out,” he said. “In fact, the question to replace the current aircraft could come first. The unit flying in rural area, there is some talk about the future bird of the unit being a twin-engine. But here again, cost has a role to play and nothing has been decided yet.”