OUT OF SIGHT, OUT OF MIND -EVALUATING YOUR DISTRIBUTION SYSTEM

NYS AWWAFall Conference – Tifft Water Supply SymposiumLiverpool, New YorkSeptember 18, 2014

Robert J. Lucas, P.E.

INTRODUCTION & OVERVIEW

1. Long-term Planning – Replacement or Rehabilitation

2. Basic Condition Evaluation ... don’t replace just to replace

3. Hydrants, Fire Flow & Hydrant Flow Tests

4. Flushing & C-Factor Tests

5. Distribution System Conditions & Design

6. Valve Maintenance & Condition

7. Non-Revenue Water

8. Calibrating & Testing Plant Meters

9. Leak Detection Survey

AMERICA’S DECAYING WATER INFRASTRUCTURE

Planning & Budgeting (No-Nonsense Example) 100 miles of pipe is your system.

½ of that or more is cast iron or A.C. (50 miles).

½ of the cast or A.C. is the oldest in system (25 miles).

Moral of the story: If you start now, replacing 1 mile of pipe per year (that’s a lot), it’ll be 25 years before you finish replacing the worst sections of main. Just start doing some .. maybe 1,000 LF

1st Subplot: It’ll take 25 more years to get rid of the other half of the worst stuff.

2nd Subplot: It’ll take 100 years to replace all of the main in your system at 1 mile per year. Exist. Ductile already 0 – 50 yr old.

3rd Subplot: If you do nothing, at some future date repairs & restoration will begin to cost more annually than if you would’ve planned, budgeted, and started replacing this year!

HOW LONG WILL THE MAINS LAST?

They Don’t Last Forever Cast Iron : 80 - 150 years

Asbestos Cement : 60 years

Ductile Iron : 120 years +/-

What Items are Involved ? Mains

Valves

Hydrants

Services

REASONS FOR PLANNED WATER MAIN REPLACEMENT

Primary Reasons

Planning & Budgeting

Approaching End of Useful Life Cycle

Experiencing Age-Related Failures

Other Benefits

Reliability

Improved Water Quality

Increase Efficiency – Better Fire Flows, Reduce Loss

EVALUATION & PLANNING TOOLS

Hydraulic Modeling Used to analyze flow / velocity scenarios to get best bang for your buck Planning / Scoping– Use Info to controls limits of Capital Improvements. Can use flushing & fire flow data to further calibrate the model Predicting Fire Flow Scenarios Tracer Analysis (for ERPs)

GIS Mapping Great historic & visual representation of distribution system The Ultimate Filing Cabinet ! Log main breaks, leaks, system maintenance, record drawings,

valve sketches, etc.

Distribution Study Collective in-depth study using all available information & tools Generally used for master planning … 2 – 10 years out Hands On - you can do it yourself

WATER DISTRIBUTION INFRASTRUCTURE

Priority #1

Areas of Frequent breaks

Critical Pipe Break Rate – How many repairs warrant a replacement

Priority #2

Undersized Mains - Population Growth=Increased Demand

Service Mains < 6”

Transmission Mains <12” - cannot handle quantity of water required without substantial velocity.

(high velocity = increased head losses = lower residual pressure = lower available flow)

When & Which Mains Should be Replaced First?

WATER DISTRIBUTION INFRASTRUCTURE

Priority #3

Asbestos Cement Water Main - DOH Requirements

Priority #4

Areas where WMs approaching end of their useful life

Mains installed pre-1940

Universal joint pipe

When & Which Mains Should be Replaced First?

REASONS FOR MAIN FAILURE

Age / Corrosion

Settlement beneath pipe

Water Hammer or Pressure Surges

Frost Heave ... Freeze/Thaw Cycle

Man Made Failures

Contractors

Manufacturer Defect

INSTALLATION COST TRENDING

Reference Pipe Cost Spreadsheet:y = 9.382x - 18733

R² = 0.9746

$-

$20.00

$40.00

$60.00

$80.00

$100.00

$120.00

$140.00

2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

Co

st

Time

Water Main Cost per Linear Foot

HANDS ON FIELD EVALUATION

Flow Testing / Fire Flow Testing:

Excellent way to measure and monitor the hydraulic capacity of the distribution system with respect to satisfying fire flow demand at a specific location.

Used to develop a portion of the fire suppression rating for a community, as established by ISO (Insurance Services Organization).

Method we use is NFPA 291

“Access” the physical condition of water mains.

Domestic demand under max. day and peak hour conditions.

Measure flow at one hydrant while noting the static & residual pressure at an adjacent hydrant.

Formula equates the results to provide available flow, QA, at 20 psi.

20 psi is the common datum at which we compare results from various tests. Also, the minimum allowable system pressure.

HANDS ON FIELD EVALUATION

When & How Often:

Test During Average or Peak Demand

Check Operation Annually

HANDS ON FIELD EVALUATION

Available Fire Flow at 20 psi residual

QA = QF x (ha.54)

hf.54

QA = Available fire flow @ 20 psi

QF = Actual full flow measured during test

ha = Pressure drop to 20 psi

hf = Pressure drop measured during test

QA = 775 gpm x (133 psi – 20 psi)0.54 = 875 gpm

(133 psi – 43 psi)0.54

Fire Flow Testing

NFPA FLOW INDICATORS(COLOR FOR CAPS AND BONNETS)

NFPA 291, Chap. 3 *

Class C - Less than 500 GPM Red

Class B 500-999 GPM Orange

Class A 1000-1499 GPM Green

Class AA 1500 GPM & above Light Blue

* Available flow at 20 psi

HYDRANTS MUST BE RELIABLE !!!

SAFETY - Preservation of Life & Property

FRIDAY, FEBRUARY 5, 1999

Faulty hydrants fanned flamesBy Marita Lowman

A fire that ravaged four West Scranton houses, damaged two others and threatened a residential city block Thursday morning might have been contained sooner if fire hydrants in the neighborhood were working and dead hydrants were tagged, firefighters said.

FIRE FLOW’S WORST ENEMY

Loss of Pipe Volume Due to Tuberculation Its Not the Hose Monster Poor Water Quality & Unlined Mains

What is Tuberculation ?Development or formation of small mounds of corrosion products on the inside of iron pipe (predominantly unlined cast iron). These tubercules roughen the inside of the pipe, increasing its resistance to water flow.

- Source: EPA

FIRE FLOW’S WORST ENEMY

What is Tuberculation …

Why does it happen ? Starts at locations where water main wall in non-homogeneous due to

crevices, scratches, mill scale or rust.

These areas create electrical potential difference, inducing a corrosion cell with water as the electrolyte.

Iron or manganese ionizes and enters into solution (at the anode)

Electrons produced will flow along the pipe wall to the cathodic area

Accepted usually by oxygen to form hydroxide ions

Ferrous ions react with the water at the anode to form ferrous hydroxide (somewhat soluble)

FACTORS THAT EFFECT CORROSION

Major Water Quality Factors

pH - Low pH generally accelerates corrosion

Dissolved Oxygen - Higher levels may accelerate corrosion

Iron & Manganese - Presence of soluble (dissolved) iron will increase the size

of tubercules

Other Factors

Silicates & Phosphates - Addition of these chemicals form protective films &

sequester dissolved iron

T.D.S. - High concentrations increase conductivity

Temperature - Elevated temps not a problem on Long Island

Hardness - Hard water decrease, soft water increases corrosion

HYDRANT FLOW TESTS

Hydrant Flow Test - Aspen Gate

0

20

40

60

80

100

120

140

0 100 200 300 400 500 600 700 800 900 1000

Flow (gpm)

Pre

ssu

re (

psi)

QF

QA

HYDRANT FLOW TESTS

Hydrant Flow Test - Hicksville Road

0

20

40

60

80

100

120

140

0 500 1000 1500 2000 2500 3000 3500 4000 4500

Flow (gpm)

Pre

ssu

re (

psi)

QA

QF

AN IMPORTANT NOTE ABOUT FLOW TESTS …..

A flow test is a snapshot of time and is a function of:

Availability of supply, booster & storage facilities.

System demand (weather & usage)

Condition of distribution system

FLOW TEST LAYOUT

Ref.: NFPA 291

FLOW TEST EQUIPMENT

Source – Pollard Water.com

MORE EQUIPMENT

Source – Pollard Water.com

GRAPHICAL METHOD

EXAMPLES OF HYDRAULIC MODEL OUTPUT …

SCENARIO 1 - HYDRAULIC MODEL OUTPUT

Show PDF file - SFWD

SCENARIO 2 - HYDRAULIC MODEL OUTPUT

Show PDF file - SFWD

SCENARIO 3 - HYDRAULIC MODEL OUTPUT

Show PDF file - SFWD

SCENARIO 4 - HYDRAULIC MODEL OUTPUT

Show PDF file - SFWD

THE C-FACTOR

THE C-FACTOR

The C-Factor test is an excellent method of determining the internal condition of a water main.

Can be done while flushing or during Fire Flow Tests.

A very important aspect of distribution piping that affects its flow capacity is friction loss. Friction loss is energy loss

Energy loss is pressure loss

Pressure Loss is loss of Fire Flow

Friction loss in pressurized pipe systems is dependent on three (3) components: Rate of flow (Q)

Internal Pipe diameter (d)

Internal condition of the pipe (C)

THE C-FACTOR

The principle measures the pressure drop between two points along a main with a known flow in one direction. Again, the value of the coefficient “C” varies according to its pipe

type and the internal condition of the pipe or roughness.

As water mains age they sometimes become tuberculated to various degrees and for various reasons.

Why? Unlined mains (cast iron)

Water corrosions (pH)

Raw water iron content

Low Flow / velocity

C-Factor Test

THE C-FACTOR

THE C-FACTOR

The lower the capacity-carrying characteristic of the mains, the lower value of “C”.

Based on the Hazen-Williams formula, flow test data is formulated to determine the value of “C”, or C-factor.

C = (4.52 x Q1.85)0.54

(f x d4.87)0.54

Where, Q = Rate of flow (gpm)d = Internal pipe diameter (in)

C = Internal condition of the pipe

f = friction factor (psi/ft)

C-Factor Test

THE C-FACTOR

Age of Pipe (years) Value of “C”

New 120

10 105

20 95

30 85

50 75

60-80 60

Some common C-values based on the age of unlined cast-iron pipe:

C-Factor Test

THE C-FACTOR

C-Factor Test - Hardy Lane

0

10

20

30

40

50

60

70

0 100 200 300 400 500 600 700 800 900 1000

Flow, Q (gpm)

Pre

ssu

re L

oss,

hL (

psi)

C120

C48

Test Length: 407'

Pipe Size: 6"

THE C-FACTOR

C-Factor Test - Papermill Road

0

10

20

30

40

50

60

70

0 100 200 300 400 500 600 700 800 900 1000

Flow, Q (gpm)

Pre

ss

ure

Lo

ss,

hL (

ps

i)

Test Length: 500'

Pipe Size: 8"

C120

C39

THE C-FACTOR

C-Factor Test - Sunrise Highway

0

10

20

30

40

50

60

70

0 100 200 300 400 500 600 700 800 900 1000

Flow, Q (gpm)

Pre

ss

ure

Lo

ss,

hL (

ps

i)

Test Length: 561'

Pipe Size: 6"

C120

C59

REVENUE VS. NON-REVENUE WATER

Revenue Water

Authorized Water Consumption (metered or unmetered)

Non-Revenue Water (NRW)

Formerly known as Unaccounted For Water (UFW) No worldwide consistency for definition of UFW or how it was

calculated UFW misleading because it is expressed in % of total pumped * UFW was a negative connotation toward poor performance rather

than a gage of efficiency Some support the mentality that all water is “accounted for” NRW based on water audit method which features a set of rational

performance indicators that evaluate utilities on system-specific attributes such as the average pressure in the distribution system and total length of water mains.

NON-REVENUE WATER (ITS MONEY DOWN THE DRAIN

Q: What is Non-Revenue Water (NRW)?

A: Total Produced minus Billed

Meter error Leaks in mains & services Well blow-off Defective hydrants Fire fighting Street sweepers Unauthorized fire hydrant use Hydrant permit use (should be metered) Illegal hookups (hard to find) Flushing Program

* NRW Needs Further Explanation … Let’s Break it Down

NON-REVENUE WATER

Non-Revenue Water1. Real Losses: Physical Loss of Water

2. Apparent Losses: Water Revenue Lost

3. Unbilled Authorized Consumption

Real Losses – happen before the meter Main Breaks & Leaks

Service Leaks (before meter)

Leaks & Overflow at Tanks

Least Expensive – tied to production costs

NON-REVENUE WATER

Non-Revenue Water1. Real Losses: Physical Loss of Water

2. Apparent Losses: Water Revenue Lost

3. Unbilled Authorized Consumption

Apparent Losses – occur at or after the meter Unauthorized consumption

Meter Error (under registering)“Old Meters Don’t Run Fast”

Reading Errors / Data Handling & System Errors

Remember, the Meter is the Cash Register

Most Expensive – happening at the retail rate

NON-REVENUE WATER

Quantity of Non-Revenue Water (NRW):(Measured as a % of Total Pumpage)

Average day: 10 MGD => Annual pumpage: 3,650,000,000

NRW: Approx. 12%

Amount of NRW: 12% x 3,650 MG = 438 MG/Year !!

NON-REVENUE WATER

Annual Cost of Non-Revenue Water (NRW):

AssumptionsCost to Supply Water: $0.90/1,000 gal

(Production Cost/Pumpage)

Average Billing Rate: $1.50/1,000 gal

Breakdown of NRW of 12% (438 MG):

6% = 219 MG Real Loss (system leaks)

4% = 146 MG Apparent Loss (customer meters)

2% = 73 MG Apparent Loss (unauthorized use)

NON-REVENUE WATER

Annual Cost of Non-Revenue Water (NRW):

By The Numbers $$$ 6% System Loss: (219 MG/1,000) x $0.90 = $197,000 !

4% Meter Loss: (146 MG/1,000) x $1.50 = $219,000 !!

2% Unauthorized: (73 MG/1000) x $0.00 = $0.00

Even if your NRW is only 5%, you are throwing away over $208,000 !!

Realistically, with the many variables its tough to get NRW below 5%

BENEFITS OF REDUCING NRW

Reduce Overall Water Production

Increase Water Sales

Improve Fire Fighting by Increased Pressure

Learn about Your System … how it operates

Its Not a Pipe Dream

CALIBRATING / TESTING PLANT METERS

Why & When ?

Accuracy of Actual Water Produced

Compare Pumped vs. Billed

1st Step to get real feel for amount of Non-Revenue Water

Annually !

Coordinate Calibration with Controls Contractor

Pump Curve is very helpful

4-20 mA signal is calibrated

VFDs get a little more involved

CALIBRATING / TESTING PLANT METERS

How ?

Ultrasonic Flow Meter Best when pumping to system

Calibrated Pitot Tube & associated chart When able to pump to blow-off

Need a way to create backpressure / simulate system pressure

WATER USAGE AND METERING

It’s all about knowledge and control…

100% metering of all system connections, including public buildings

How old are your meters? (… the cash register)

Recommended meter change schedule:

5/8”, 3/4”, 1” - 10 years (up to 15 years ok)

1-½” and 2” - 4 years

3” & 4” - 2 years

6” & over - annually

Calibrate plant meters – AWWA recommends annually! Venturi Tubes, Orifice Plates, Paddle wheel

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WATER USAGE AND METERING

Do you know your amount of Non-Revenue Water?

Radio Road vs. Manual Read / touch pad

Meter Management – Control Apparent Losses

Are you making any money?

Meter selection – based on flow requirements, meter type & selection critical to accurate metering

How wireless meter-reading solves problems Hourly readings pinged at regular interval

3-day period

Looking for unusually high continuous usage

Send out high use letters or call & visit

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WATER SUPPLY AUDITING

Accounting for Your Water Consumption Crunch your own numbers

Look at your pumpage numbers Compare to your billing figures How do your meter readings look Do the results suggest something is out of whack

Determine how much water you’re pumping that you’re not getting paid for? Non-Revenue Water

Lost water = Lost $ Non-Revenue Water is NOT the same as unaccounted for

water 10% loss – AWWA benchmark for leak detection and

accountability Biggest mistake is OVER-estimating unmetered use

53

WHAT ARE YOU GOING TO DO ABOUT IT?

Reducing System Water Losses:

1. New, accurate meters coupled with block rate pricing is a major means of conservation.

2. Leak detection – Have you completed one in the last 10-15 years?

3. During flushing, turn off hydrant when clear and don’t leave it running and come back later.

4. Reduce the amount of water Fire Departments need for training.

5. Fines for unauthorized hydrant use. Encourage residents to report unauthorized use.

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WHAT ARE YOU GOING TO DO ABOUT IT?

6. Public Outreach:

Water Efficient Landscaping (Xeriscaping)

Rain sensors – we’ve all seen examples of not using them!

Odd/even watering days

New moisture sensors

Education via community development and school programs

7. Encourage water audits of top 10 users

8. Use Free Water Audit Software by AWWAhttp://www.awwa.org/Resources/WaterLossControl.cfm

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So What Can We Do ?

Leak Detection –

Control Real Losses

LEAK DETECTION

Leak Detection Survey

Utilize surface listening equipment – ground or clamp-on microphone

Ultrasonic or conductive equipment - correlators Can be done by WD personnel with inexpensive listening

equipment – but who has time for that? Contract services out to leak detection company Leak Detection Survey is a must .. if you have never done

one Or, if it has been 10-15 years since one was completed Even if you think your NRW is around 5% Quick Return on Investment

You are in denial if you think you will not find any leaks!!!

LEAK DETECTION

Cost of leak detection survey by qualified firm: Price range: $125-150 per mile of pipe

If you have 100 miles, 100 miles x $125 = $12,500

If you have 180 miles, 180 miles x $125 = $22,500

Find & fix (2) bell joint leaks, and cost of the survey is covered in the first year !

Repair / Restoration costs not considered Pay now or pay later …

Restoration costs later (after a break) could be extremely costly!

Even if you consider repair costs of $25,000 [explain], the payback period is still only 3 years … you can’t find a better investment.

LEAK DETECTION

Reduce NRW by 1% via Leak Detection?? 1% x 3,650 MG x ($0.90/1,000) = $33,000 annually !!

2% x 3,650 MG x ($0.90/1,000) = $66,000 annually!!

Food for thought: Annual cost of pinhole leak (1/16” hole @ 60 psi = 0.56 gpm)

0.56 gpm x 60 min x 24 hrs = 813 gpd =>

813 gpd x 365 days/year = 296,745 gal/year

296,745 gal/year x ($0.90/1,000) = $270

Hydrant maintenance crew can simply check and tweak hydrant for a quick $270 savings.

COMPRESSION TYPE - OPEN WITH PRESSURE

COMPRESSION TYPE - OPEN AGAINST PRESSURE

LEAK DETECTION

Bell joint leak (8” main) @ 15 gpm

15 gpm = 21,600 gpd = 7.884 mg/year

7.884 mg/year x ($0.90/1,000) = $7,100 annually

5-10 small leaks can account for 1% of UFW!!

..

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BEST THING SINCE SLICED BREAD ?!

Who knows what it is ???

Hold On .. I’ll Show You

TRAILER-MOUNTED VALVE OPERATING MACHINE

TRAILER-MOUNTED VALVE OPERATING MACHINE

WHY VALVE MAINTENANCE ?

If its broke, closed or inoperable, chances are its restricting flow in your system !

Consider Return On Investment

Cost of Machine vs. Valve Replacements

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OUT OF SIGHT, OUT OF MIND –EVALUATING YOUR DISTRIBUTION SYSTEM

Questions ???

MORE …

IF WE HAVE ENOUGH TIME

REPLACEMENT ALTERNATIVES

Rehabilitation of Existing Water Mains

Install new internal lining

Chemical Cleaning

Pipe bursting

Be aware of potential for Bio-film growth, Iron Bacteria

REPLACEMENT ALTERNATIVES

Install Internal Lining

Advantages Restoration of friction factors to new values

Elimination of rusty water

Improved fire flows

Disadvantages Temporary by-pass is required for existing service lines

Potential for bacteria or vandalism

Field applications of internal liner are inferior to those applied in foundry

No structural improvement to existing water main is gained

Not really that cheap here on Long Island

WATER MAIN REPLACEMENT

New Installation – Open Cut

Construction cost Varies with road type, composition, agency

Restoration can be 25-50% depending on road agency reqs.

Multiple factors affect bid prices

Long service life

Familiar Method & Material

Services transferred, Main abandonment in-place

WATER MAIN REPLACEMENT

Evaluate your Distribution System

Distribution Study – Determine your Priorities

Short Term Planning

Leak Detection

Communicate with Road Agencies

Long Term Planning

Start Now !!!

Budget According to your Evaluation & Needs

Set Goals

WHY FLUSH ?

Improve Water Quality …

aesthetic concerns – taste, odor, clarity

Improve disinfection.

Reduce or eliminate positive bacteria results.

Improve hydraulic capacity.

Exercise valves, test hydrants.

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WATER MAIN FLUSHING

Conventional - Continuous blowoff

Opening hydrants at random with no clearly defined plan

No valve isolation

Unidirectional flushing (UDF)

Effective cleaning

Long term benefits

Uses 40% less water than convention method.

Can be performed concurrently with other programs.

Eliminates the need to use every hydrant.

FLOW VELOCITY REQUIREMENTS

Effective flow velocity ranges vary from 2.5 to 12.0 fps.

Desired velocity range 3.5 to 6.0 fps for most systems.

Velo city Pipe (dia) 6" 8" 10" 12" 16"

3.5 fps (min) 308 548 856 1,233 2,192

6.0 fps (desired) 529 940 1,468 2,114 3,758

Flow Requirements in gpm

WATER MAIN FLUSHING & DE-CHLORINATION

Dechlorinating Diffusers

Source : Pollard Water.Com

Hydrant Mount Truck Mount

IT’S THE LAW

Be cautious the next time you flush on where you are flushing to/into, and what chemicals are being used to dechlorinate.

DECHLORINATION REQUIREMENTS

Varies State To State

Stringent Regulatory Discharge Limits For Chlorinated Water.

CA, OR, WA, NV, MD & WV - < 0.1 mg/l (ppm)

Endangered Species Act (ESA)

Environmental Protection Agency (EPA)

Federal Clean Water Act (CWA)

State, County, Local Regulations

DECHLORINATION METHODS

Dependent on Concentration (ppm) of Chlorine Needed to be Neutralized

Potable Water < 4 ppm Chlorine

Super Chlorinated 50-300 ppm Chlorine

Dependent on Volume (gpm) of Water

100’ of 8” Main (low gpm – relative)

Reservoir 3.5 Million Gallons

(high gpm – relative)

CHEMICALS REQUIRED TO NEUTRALIZE CHLORINE

Residual Chemical Required, lb (kg)

Chlorine Sulfur Sodium Sodium Sodium

Concentration Dioxide Bisulfite Sulfite Thiosulfate

Mg/L (SO2) (NaHSO3) (Na2SO3) (Na2S2O35H2O)

___________________________________________________________________________

1 0.8 (0.36) 1.2 (0.54) 1.4 (0.64) 1.2 (0.54)

2 1.7 (0.77) 2.5 (1.13) 2.9 (1.32) 2.4 (1.09)

10 8.3 (3.76) 12.5 (5.67) 14.6 (6.62) 12.0 (5.44)

50 41.7 (18.91) 62.6 (28.39) 73.0 (33.11) 60.0 (27.22)

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