new york city water supply system

8/13/2019 New York City Water Supply System

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New York CityWater Supply System

Professor ChangCIEN E3004

Final Project ReportApril 30, 2013

Group 10: Nida Dangra, Nikita Gupta, Luke Henderson, and Jakub Karas


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Executive Summary

This report provides description, issues and solutions of the New York City Water Supply

System. There were several key questions which were asked in the planning portion of this

project and these included the financing of the system, the transportation of water from its source

to the taps, the treatment it receives during that voyage, and the threats and vulnerabilities which

it faces every day.

The system is financed based on revenue bonds issue by one of the institutions involved

in the O&M of the system: the NYC Municipal Water Finance Authority (NYW). Since

conception, the NYW is also responsible for paying off the general obligation bonds issued years

ago to build the system.

The Underground Network section describes the issues with the current piping between

the reservoirs in upstate New York and taps in NYC. As its discussed, the current piping is

constantly monitored and replaced by portions as the need arises. Thats also why the cost of

replacing the aging infrastructure to raise the standards will be spread out over time and will not

be too great to bear.

Next the singular characteristics and treatment of water are discussed. In this case it had

been found that NYC water is only minimally treated but multibillion dollar investments have

been made to prepare the city for the need to treat its water in the future.

Lastly, vulnerabilities and threats to the system have been investigated. From among

those, two major ones have been discussed: terrorism and climate change. The DEP responded to

the first one with increased monitoring of the system and preparation of post-attack plans while

the second one has been improved via integration with other infrastructure systems to ensure a

quick response to a weather crisis.


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Table of Contents

Introduction Page 1Institutional Issues Page 1Underground Network Page 3

Water Filtration Page 7Vulnerabilities Page 9Conclusion Page 12References Page 13Appendices Page 15

Appendix A

Figure 1. New York Citys Water Supply System Page 15Figure 2. New York City Distribution Page 15Figure 3. Water and Sewer Service Line Page 15

Figure 4. Automated Underwater Vehicle Page 15Figure 5. Geology along Delaware Aqueduct Page 16Figure 6. Accessibility of Wawarsing and Roseton Page 16Figure 7. Sectional View of Tunnel and Potential Leak Pathways Page 16Figure 8. Planned Internal Grout Repair Page 16Figure 9. Internal Grout Repair Process Page 16Figure 10. Bypass Tunnel Page 17Figure 11. Elements and vulnerable points in a general water supply system Page 17

Appendix B

Table 1. Natural hazards and human related threats to a water supply system Page 17

Appendix C

PowerPoint Presentation Page 18


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Introduction

The New York City Water Supply System is one of the largest and most functional in the

world. It dates as far back 1776 when the first reservoir was constructed. Since then it had grown

steadily and, as it stands today, it serves 9 million people with over 1.2 billion U.S. gallons of

minimally treated water daily. It is managed by 3 agencies, which work independently of the

New York City government. The purpose of this paper is to examine different issues associated

with this system and to relate them to some of the concepts covered in class. Our group decided

to focus on four issues, none of which is independent of each other. These topics include

institutional issues and the financing of the system, underground network and the transportation

of water from the reservoirs to our taps, filtration and treatment of water, as well as

vulnerabilities and various threats to this system.

Institutional Issues

There are three main institutions responsible for the operation, maintenance, and

financing of the New York Citys Water Supply System. The largest of them is the New York

City Water Department of Environmental Protection (DEP). It is responsible for the operation

and maintenance of all the assets (bridges, reservoirs, aqueducts, etc.) to ensure the delivery of

drinking water to over 8 million inhabitants of the Greater New York area. The financing is

performed by The New York City Municipal Water Finance Authority (NYW). This entity

provides the funding necessary for O&M and new construction projects through the issuance of

bonds, commercial paper and other obligations.1The last agency involved is the New York City

Water Board whose responsibility is to set the rates for water and sewer usage as dictated by the

costs of operation and maintenance. The Water Board is also responsible for collecting the

payments from the users. With this kind of varied institutional power, the issue to be discussed


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would be the discrepancy between the funding needed (NYW) and the amount of taxes/rates put

on people and maintaining the balance between the two.

Initially all the components of the water and sewer system were under the control of

NYCs government and in the same bag with all other investments such as roads, airports,

transportation system, etc. Back in the day the financing of all these components was based on

general obligation (GO) bonds. These bonds are generally repaid based from the taxes and other

revenue generated by all the infrastructure nodes in a given municipality (in this case NYC). This

changed after 1984 when the authority on the system changed over to NYW and the Water

Board. This was a pretty big change for the customers who switched from paying a fixed price

based on frontage and number of piping fixtures to paying for the amount of water actually used.

In terms of finance, the GO bonds were replaced by the revenue bonds which are meant to pay

for the expenses of the water system and sewer system and be repaid based on the revenue

generated by the system alone. This redirection of power created a problem, however: what to do

with all the repayments on the GO bonds issued before 1984? Which entity should take care of it

and in what way?2

The issue was solved on the promise that a portion of the water and sewer system revenue

will be handed over to NYCs government to pay for the GO bonds. The amount of the

transferred revenue became problematic and remains unclear until this day. It had been agreed

that the City will get either the debt service of the GO bonds or 15% of the debt service of the

revenue bonds. This formula worked fairy well for about a decade but became controversial in

the last few years when the NYC government started making millions of dollars on the revenue

since the debt service of the GO bonds decreased over time.3What is the solution in a situation


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where a large portion of the water and sewage revenue goes to the government based on a 30

year old law?

An obvious solution has been proposed by the New York City Comptroller who argued

that the government is not entitled to all that revenue and that it should be split between new

investment in water and sewage system or lowering the rates for the customers. The government

disagreed and the problem has remained. Without knowing all the facts it appears, as its often

the case where money is involved, that the government acted selfishly and, unless the money has

been put into major works of utmost importance, it has bit its own tail. This revenue, totaling

about $500 million could be utilized for much needed repairs on this aging water supply system.

It could also be put aside for future works or used to repay the debts of the water and sewer

system. Thus, as it stands and from the point of view of the water system, the money had is being

wasted when it could be used in more worthwhile ways.

Underground Network

Water supply in New York City comes from three individual sources and they are the

Catskill/Delaware supply system, the Croton supply system, and the groundwater supply in

southeastern Queens. Water from the reservoirs comes to New York City through three main

pipelines, the New Croton Aqueduct, the Catskill Aqueduct, and the Delaware Aqueduct (Figure

1). Water is distributed throughout New York City through three water mains. Tunnel No. 1 and

Tunnel No. 2 were put into service in 1917 and 1936 respectively. Tunnel No. 3 is still under

construction. Stage 1 of Tunnel No. 3 is expected to go into service by the end of 20134(Figure

2). Tunnel No. 1 and Tunnel No. 2 have not been inspected or repaired since the first time they

were put into service. One of the big reasons for the construction of Tunnel No. 3 is to allow the

DEP to maintain the performance of the drinking water system so that there will be no


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interruption to service while Tunnel No. 1 and Tunnel No. 2 are being rehabilitated. Tunnel No.

3 will also provide expanded distribution as the population of the city is expected to increase by

1.1 million between 2000 and 2030.5Overall, the reliability of the New York City Water Supply

System will increase.

There have been allegations made that the New Croton Aqueduct, which is over 100

years old is in serious need of repairs.6Statements from the DEP supporting or refuting such

claims have not been found. However, more than 90% of the water comes from the Delaware

and Catskill Aqueduct, so the New Croton Aqueduct may not be considered critical. Also, in

2011, 100% of the citys drinking water came from the Catskill/Delaware Supply.

7

There can be

multiple reasons for this. The three aqueducts were designed and built with multiple

interconnections to allow flexibility and exchange of water. Other than redundancy, in case of

pipe leaks and breaks, this allows for mitigation in case of localized droughts or excess water.

Either the DEP was taking from the Catskill/Delaware supply to recover reservoir levels in the

other supplies or was conducting reviews and checks on the other systems. There was a press

release in November 2011 stating that the reconstruction of five dams in the Croton Watershed

had been completed.8 Since the DEP does not state in the 2011 Drinking Water Supply and

Quality Report, the reason for only the Catskill/Delaware supply being the source of drinking

water in 2011, it may be any combination of above stated reasons or something else entirely. It

can be said though, that the New Croton Aqueduct, which may be in serious need of repair, is

currently not experiencing heavy usage.

It is important to correct leaks in the systems as soon as possible. Leaks can contribute to

increased flow into wastewater systems, can reduce level of water in reservoirs unnecessarily,

and if left unattended, lead to severe water damage such as pipe bursts and erosion of


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surrounding and supporting earth foundation. For customers it can lead to a spike in the water

bill. In NYC, homeowners are responsible for service lines that run from the building to the

municipal service lines in the street (Figure 3). DEP has a program for electronic alerts in case of

a spike in water usage and a Water and Sewer Service Line Protection Program or insurance

program in case of damage. For municipal service lines, the DEP has the Leak Detection

Program. Every neighborhood gets checked at least once every three years. Sophisticated

listening equipment is used to check every water main for leaks by listening to the flow of water

in water mains. Leaks can be identified by a distinctive noise pattern that is produced in water

flow. Approximately 500 leaks are found each year.

9

For leaks, proper operation and

maintenance is important to prevent high future capital costs in repairing pipes or foundations.

One huge leak repair project is the Delaware Aqueduct Leak plan. The DEP has been

monitoring leaks in the Delaware Aqueduct Rondout-West Branch Tunnel for more than a

decade through geological investigations, well monitoring, tunnel flow monitoring, surface

expressions monitoring, and Automated Underwater Vehicle (AUV) inspections (Figure 4). The

Delaware Aqueduct passes through a series of rock layers at 30 oangles (Figure 5). The cracking

occurs at two points along the aqueduct, Wawarsing and Roseton (Figure 7). The cracking areas

are located near and at the limestone layers. Limestone is considered poor geologysince it is

relatively soft and water/acid soluble when compared with shale or sandstone.10The Wawarsing

Public Advisory Committee considered several concepts and ruled out the ones that were

unfeasible or unreliable. Repairing from exterior would be unreliable since it involves excavation

and then filling, which may not be done properly. A parallel tunnel would be very expensive,

take decades, and would be unnecessary. Repair from interior would involve stopping water

traffic and would be under a time constraint. A bypass would be feasible but exact locations of


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leakages are unknown so no guarantee that whole leakage area is bypassed. The Wawarsing area

has 485 linear feet of cracking. It can be easily accessed and there is no risk to tunnel flooding

(Figure 6). Internal grout repair would therefore be used for Wawarsing. Internal grout repair

would involve unwatering the tunnel, drilling grout holes, and injecting grout (Figures 8, 9). In

the Roseton area there is 5200 feet of cracking, which is a significantly larger area and would

require shutting down water traffic for a much longer time if repaired internally. It also has poor

tunnel access and a risk of flooding since it is at a low point in the tunnel (Figure 6). This led to

the bypass tunnel solution in Roseton (Figure 10).10The Delaware Aqueduct carries more than

50% of NYCs drinking water.During the connection to the bypass tunnel, the city will need an

alternate source of water. The groundwater supply system in Queens will be reactivated before

2020 when the connection is planned to be made. Before reactivation, the groundwater facilities

will be upgraded and repaired to achieve reliable operation, maximum capacity, and drinking

water quality standards.11

The total cost of the project has been estimated to be $1.19 billion. A simple analysis can

be done to see how many days it will take after the completion of the project for the project to

pay for itself. The current water rate is $3.39 per 100 cubic feet or approximately 748 gallons.12

It will be assumed that the water rate charged will increase in time due to inflation and thus the

future value of water in present terms will be the same as the present value of water. 13An

optimistic approach will be taken to this analysis and it will be assumed that the project saves 35

million gallons of water every day. So the amount of money saved every day will be:

(35,000,000 / 748) $3.39 = $158,622.99. So the number of days till the project will be

completely paid for: $1,190,000,000 / $158,622.99 = 7,502.06 days or about 20 and years.

This may seem like a long time, however the Delaware aqueduct has been in use since 1945 or


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68 years. If the service life of the aqueduct can be significantly extended by this project then

hopefully it will last longer than 20 years so the project can be justified. It should be noted that

if the leaks arent fixed they could potentially damage the pipe structure as well and increase

leakage. This potential for disaster avoidance was not considered in the analysis.

Construction projects regarding the system of pipes and shafts that were discussed and

mentioned by the DEP never indicate a complete replacement of a tunnel or aqueduct. The

advantage in the construction of a network of pipes is that it can be replaced or constructed in

parts compared to replacing a bridge, where most of the work has to be done all at once and

continuously. For this reason, the term service life may not apply to such systems. Any length of

piping that seems to be failing in performance or reliability can be replaced without disrupting

the whole system. It can be said that new technology or standards in piping and aqueducts may

require a complete overhaul of the system, but even this can be done in parts. For example, if a

portion of the old technology system fails, replacement by the new technology can be limited to

that portion with sufficient connection between the two types of piping. Thus replacement of the

old system will be gradual and the high initial cost of complete replacement will be spread out

over a longer period of time.

Water Filtration

With a volume of over one billion gallons of water delivered each day, it comes as no

surprise that water treatment and filtration is no trivial detail for the city; any minute

contamination of the water would affect millions in the city and around.14Astonishingly enough,

despite this huge responsibility, New York City is the largest of the few major cities in the

United States, which does not treat its water before distribution (though it does undergo basic

processes such as chlorine addition). This is made possible by a couple of factors such as the


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citys long standing record in water purity and a series of preventive measures put in place to

assure the continuation of this record. Despite these measures and the natural quality of the

water, there is an understanding that tightening water quality standards as well as development in

and around the watersheds will eventually lead to the mandatory treatment of incoming water,

and the city is already preparing for future requisites.

In order to stay exempt from filtration/treatment, every year New York Citys DEP must

submit to the New York State Department of Health a petition to be exempt from water

filtration.15This petition is backed by careful analysis and data samples of water quality, proving

that the untreated water attains the set standards for purity, turbidity, and cleanliness. This

natural purity comes from the natural quality of the water in the watersheds, which in turn is

conserved by conservation measures put in place by the DEP.16 These measures include the

acquisition, by the state, of land around the watersheds which drain directly into the lakes and

rivers, the close monitoring of pollution levels in the area to pinpoint pollutants if they are

present, and cooperation with private land-owners in the area who have agreed to take particular

caution with their use of chemicals and the run-offs from their lands. These measures have so far

been effective in keeping the water quality above standard, even in periods of draught, where

low water levels tend to raise average pollution levels.

One exception to this flawless record has recently been found in the oldest of the

watersheds: the Croton watershed. Indeed, in recent years (starting in 1998) it has been found

that under drought conditions, the reservoir systems water has yielded sub-benchmark water

clarity.17Though having no impact on health, water clarity remains an important consideration in

quality control as it affects taste and confidence in the water. 18To deal with this problem, the

city had to build its first permanent water treatment plant to service water coming from the


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Croton aqueduct. It is about to become fully operational. This move seems to be reflective of the

gradual shift to treated water on the citys behalf.

Indeed, with the continued urbanization of the watershed areas and thus the disruption of

the local water cycles, the city is predicted to continue this gradual transition to filtered water.

Already, the city has invested a staggering $2.8 billion in the construction of the Croton system

treatment plant and has plans to build a set of UV water treatment plants for the other two

reservoirs in Westchester at a cost of $104.6 million. 19 These treatment plants would use

powerful UV illumination to kill most pathogens in the water. These new treatment plants would

have the capacity to treat up to 2 billion gallons of water a day, more than enough to catch up

with the citys water needs by 2014.

As we have seen, New York City benefits from access to uncharacteristically pure water,

which it uses daily without the need for filtration. However, guided by foresight and caution,

massive investments have been made in the last decade to prepare the city for a switch from

untreated to treated water. These expenses, though costly, should help assure the continuation of

clean water supply to the city for decades to come.

Vulnerabilities

The New York City water supply system is also vulnerable to certain external factors that

include terrorist attack or sabotage, as well as climate changefactors that are currently

relevant. The September 11thattacks on the World Trade Center in New York City was a major

turning point for the security of water infrastructure, as attention was drawn to the security of

many institutions, facilities, and systems, including water supply systems and water quality

infrastructures. These systems have long been recognized as being potentially vulnerable to

terrorist attacks of various types, including physical disruption, bioterrorism, chemical


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contamination, and cyber attack.20For example, there was a reported threat to contaminate the

water supply of New York City with nerve gas in 1972 that never actualized; this shows terrorist

attacks were always a concern, but became a heightened concern after 2001.

With sabotage and terrorist attacks being a growing concern, research was conducted on

water supply systems in order to understand and control vulnerabilities because water is a

fundamental resource that society and human welfare depends on. A typical water supply

system, such as the one in New York City, consists of water sources, raw water transmission

pipes, water treatment plants, and water distribution networks.21Considering this, five vulnerable

areas were identified as opportunities for both natural and human-related influences due to their

accessibility, as shown in Figure 11: (1) water sources (e.g., river); (2) water treatment plant that

removes impurities and harmful agents and makes water suitable for all uses; (3) water

distribution pipelines that deliver clean water; (4) storages (tanks); and (5) other facilities the

water is transported to.22

The numerous types of risks and threats that New York City, or any city, could be

affected by are shown in Table 1 and can be categorized into natural hazards and human-related

threats. These varied threats show that any water infrastructure system is also highly linked with

other infrastructures, especially electric systems that control power and its restoration and

chemical plants that treat the waterconnecting the security of all of these systems to the overall

security of the water supply system. One advantage that New York City has in situations of

power loss, though, is that 95% of the total water supply is supplied by gravity and only about

5% of the water is regularly pumped to maintain the desired pressure.23

After the terrorist attacks of 2001 brought to attention the vulnerability of the water

infrastructure in New York City, water system security recommendations were made by state and


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local governments. Interestingly, in the aftermath of these attacks, research shows that the

citizens of the city believed that it was not following through with post-September 11

recommendations to increase security for its water supply system, leaving it vulnerable to

possible terrorist attacks, according to a report from a state legislative committee.24Perhaps not

directly in response to this, the DEP increased security over New York Citys water system, even

though an attack on the water supply is believed to be less likely than other attacks due to the

difficulty of carrying it out. The risk is mitigated by the purification process and detection of

toxins near the upstate reservoirs, before the water actually reaches the New York City

reservoirs. Nevertheless, the DEP restricted access to water supplies and supply system

components (such as tunnels and aqueducts), barred all fishing and hunting, and monitored and

patrolled restricted areas by helicopter and fixed-wing aircraft.25Despite these precautions, it

was believed that the number of police officers was not enough to patrol the watershed, which

extends 125 miles north of the city.26Thus, over the course of five years, the number of positions

was increased from 39 to 142. The NYC government also increased the number of daily water

samples it takes.27

In the aftermath of the attacks, to help restrict access to sensitive areas, DEP actively

sought to acquire the property surrounding those areas and has a large police force and contracts

for security guard services. In August of 2002, the Bioterrorism Act was signed and this included

the creation of an emergency response plan and an analysis of vulnerability to terrorist attacks. In

New York State, all community water systems that serve more than 3,300 people are required by

State Public Health Law to prepare and submit a water supply emergency plan (ERP). As stated

by the New York State Department of Health, ERPs need to be complete, up to date, organized

to find important information quickly, and readily available when needed. Emergency response


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plans must include an assessment of vulnerability to water supply contamination and disruption,

including the possibility of terrorist attack.28The NYC government increased its monitoring in

2006 with tiny fish called bluegills that react rapidly to minute changes in water purity.29

Climate change is another recently relevant topic that highlights the vulnerabilities of the

New York City water supply system. Although climate change affects wastewater management

in the city more than it does the water supply system, the city has started thinking about

precautions to take with the sea level rise, increased coastal flooding, more frequent and intense

rainstorms, and increased annual precipitation. 30 The NYC government has started to take

precautions included in the 2007 city plan by considering integration of the water supply system

with other regional systems to increase flexibility in the event of localized disruptions, as well as

adding construction of increased redundancy in the water supply infrastructure.31

Conclusion

Since Roman times, there has been an understanding that water supply regulation and

infrastructure is a necessity for any large city to prosper. With 8 Million people, New York City

stands as one of the worlds largest cities, and quenching its thirst daily falls to a complex

network of interdependent infrastructure and cooperating institutions. To continue to operate on

a daily basis, yielding an average of 1.2 billion gallons a day, this system has to be constantly

serviced, surveyed and studied to minimize vulnerabilities and assure its sustainability for

tomorrows generation and the next, allowing the city to continue its economic growth without

having to pause for a drink.

References

1"About NYW." The Official Home Page of The NYC Municipal Water Finance Authority. NewYork City Water Board. Web. 28 Apr 2013. .


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2Jain, Rahul, Maria Doulis, and Charles Brecher. "New York Cit'ys Water and Sewer System: Isthe Rent Too Damn High?." (December 2011): Web. 21 Apr. 2013..3Jain, Rahul, Maria Doulis, and Charles Brecher. "New York Cit'ys Water and Sewer System: Is

the Rent Too Damn High?." (December 2011): Web. 21 Apr. 2013..4"City Water Tunnel No. 3."NYC Department of Environmental Protection. N.p.. Web. 27 Apr2013. .5The City of New York. Department of City Planning. New York City Population Projections byAge/Sex & Borough, 2000-2030. 2006. Print..6"Threats to NYC's Tap Water."Riverkeeper: NY's clean water advocate. N.p.. Web. 27 Apr2013. .7The City of New York. Department of Environmental Protection. New York City 2011Drinking Water Supply and Quality Report. Web..8"DEP Rebuilds Five Dams in the Croton Watershed." NYC Department of EnvironmentalProtection. N.p., 15 Nov 2011. Web. 27 Apr 2013..9"DEP Announces Leak Detection and Catch Basin Cleaning Locations for July."NYCDepartment of Environmental Protection. N.p., 08 Jul 2004. Web. 27 Apr 2013..10The City of New York. Department of Environmental Protection.Delaware Aqueduct LeakAction Plan. Wawarsing Public Advisory Committee: 2010. Web..11The City of New York. Department of Environmental Protection. New York City 2011Drinking Water Supply and Quality Report. Web..12The City of New York. New York City Water Board. Water and Wastewater Rate Schedule.2012. Web. .13Randall, Judy. "New York City seeking 5.6 percent water rate increase; Staten Island publichearing April 29." Silive. N.p., 05 Apr 2013. Web. 27 Apr 2013..14"About Watershed Protection."About Watershed Protection. NYC DEP, n.d. Web. 25 Apr.2013.15"Croton Water Filtration Plant." Croton Water Filtration Plant. NYC DEP, n.d. Web. 25 Apr.2013.16"Regulatory Background."Regulatory Background. NYC DEP, n.d. Web. 25 Apr. 2013.17"History of New York City's Water Supply System."History of New York City's Water SupplySystem. NYC DEP, n.d. Web. 25 Apr. 2013.18"The Croton Water Filtration Plant Project." The Croton Water Filtration Plant Project. NYCDEP, n.d. Web. 25 Apr. 2013.19Risinit, Michael. "Westchester Aims to Join NYC on Water Plant for UltravioletTreatment." The Journal News. Journal News, 26 Sept. 2012. Web. 25 Apr. 2013.20"Attacks on Water Supplies." Terrorism Research & Analysis Consortium. Web. 27 Apr 2013..


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21Saadati, Sara. "Vulnerability Assessment and Risk Reduction of Water Supply Systems." N.p.,n.d. Web. 27 Apr 2013.22Saadati, Sara. "Vulnerability Assessment and Risk Reduction of Water Supply Systems." N.p.,n.d. Web. 27 Apr 2013.23

http://www.nyc.gov/html/dep/html/drinking_water/history.shtml24"Report: NYC water system still vulnerable." CNN.com. CNN, 19 May 2002. Web. 27 Apr2013. .25Lloyd, Emily. "Security Over New York Citys Water System." State of New York, 25 Apr2006. Web. 27 Apr 2013. .26Worth, Robert. "New Concern About Security Of the Water Supply." The New York Times,14 Oct 2001. Web. 27 Apr 2013. .27Gleick, Peter. "Water and Terrorism." Pacific Institute, 14 Aug 2006. Web. 27 Apr 2013..28"Preparing Emergency Response Plans - Drinking Water Systems." Department of Health.Web. 27 Apr 2013..29Zeranski, Todd. "NYC Uses Fish to Guard Water Supply From Terrorists."Bloomberg.com.N.p., 23 Aug 2006. Web. 27 Apr 2013..30Levine, Larry. "New Report Highlights Vulnerability of NYC Water Infrastructure to ClimateChange -- and the Citys Efforts to Prepare." SWiTCHBOARD. N.p., 26 Jul 2011. Web. 27 Apr2013. .31"Local government perspective on adapting water management to climate change." WorldWater Council. N.p.. Web. 27 Apr 2013..

Appendix A


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Figure 1. New York Citys Water Supply System Figure 2. New York City Distribution

Figure 3. Water and Sewer Service Line

Figure 4. Automated Underwater Vehicle


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Figure 5. Geology along Delaware Aqueduct

Figure 6. Accessibility of Wawarsing and Roseton

Figure 7. Sectional View of Tunnel and Potential Leak Pathways Figure 8. Planned Internal Grout Repair

Figure 9. Internal Grout Repair Process


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Figure 10. Bypass Tunnel

Figure 11. Elements and vulnerable points in a general water supply system31

Appendix B

Table 1. Natural hazards and human related threats to a water supply system31


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Appendix C


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