Water Quality Modeling used to Inform Operational Decisions for the NYC Water Supply: A Ten Year...

Water Quality Modeling used to Inform Operational Decisions for the

NYC Water Supply: A Ten Year Retrospective

Mark S. Zion, Donald C. Pierson,Elliot M. Schneiderman and Adao H. Matonse

New York City Department of Environmental Protection

NYC Watershed/Tifft Science and Technical SymposiumWest Point, New York

September 18-19, 2013

2

Introduction

• Over the last decade, DEP has developed and applied an extensive suite of water quality and water system models which are used to analyze turbidity transport in the Catskill System.

• Elevated turbidity can be an issue for the Catskill System of the NYC water supply during and after periods of high streamflow.

• Informed operations during event periods can help to mitigate the impacts of turbidity on the water supply

• This presentation describes the models and illustrates how the models have been applied to help inform operational decisions to maintain high quality water at supply intakes.

3

System Description

Kensico

Ashokan Reservoir Options

DIV

IDIN

G W

EIR

EAST BASIN

WESTBASIN

RELEASECHANNELCATSKILL

AQUEDUCT

GATEHOUSE

DIVIDINGWEIRGATE

4

Model Description

Kensico

CEQUAL-W2 Two Dimensional Reservoir Models

Ashokan

Esopus Creek

DividingWeir

CatskillAqueduct

ReleaseChannel

Spillway

Catskill Influent

Catskill Effluent

Delaware Effluent

Delaware Influent

• CEQUAL-W2 Models adapted to simulate turbidity transport by Upstate Freshwater Institute (UFI).

5

Catskill Influent

Catskill Effluent

Delaware Effluent

Delaware Influent

Model Description

Kensico

Turbidity Profile

CEQUAL-W2 Two Dimensional Reservoir Models

Example Longitudinal Profiles Temperature

6

E. Br. Delaware R.

Delaware R.

Lackawaxen R.

Mongaup R.

Neversink R.

Lehigh R.

Tohickon Cr.

Musconetong R.

Assunpink Cr.

Crosswicks Cr.

N. Br. Rancocas Cr..Schuylkill R.

White Clay Cr.

Red Clay Cr.

Tulpehocken Cr.

Jordan Cr.

Dyberry Cr.

W. Br. Lackawaxen R.

Perkiomen Cr.

Maiden Cr.

100

105

110

115

120

125

130

135

140

145

150

155

160

165

170

175

185

190

200

205

210

215

220

225

230

235

240

245

250

255

260

265

270

275

280

285

290

295

300

305

310

315

320

325

330

335

340

345

350 355

360

365

366

370

375 380

385390

395

400

405

410

415

420

425

430

435

440

445 450

455

460

465

470

475

480

485

490

495500

505

510

515

520

525

530

535

540

545

550

599

600

610

612

615

625

630635

650

655

660

670

675

680

685

690

695

700

705

710

715

720

722

725

730 735

740

745

750

755

760

765

770

775

780

900

910

991

992

994

995

996

997

999

180

195

620

D&R Canal

657

OASIS Model of

Water Supply System and

Delaware River Basin

New York City

J eromePk

Stiles v l

C allic oo

Oak landV

N ev rs R iv

W oodbrne

Montague

Por tJ erv

MongpR iv

H aw ley __

W ils onv l

Barry v il

Toc k s Is l

Ph ilade l

Sc huy lk l

D em_5BPA

R eading_

BlueMrs h

Potts tw n

Berne___

Landingv

Limer ic k

Grater fd

C hadds Fd

W ilmingt

D emd_8D E

MemBridg

N ew ark __

W ooddale

D emd_8PA

C hes ter_

D em_7BN J

D em_5APA

D em_7AN J

TrentInc

D emd_4N J

PPleas ntPipers v l

D emd_6PA

Glendon_

W alnutp t

Be ltz R iv

W hitehv n

Merr lTrn

MerrlR es

Belv ider

Lehigh R.

D &R -King

W BrLac k w

Prompton

H ones dal

661

706

621

702 703707

701

699

766

761

FEW alter

B eltz R esAquas hic

Palmer tn

Sc hnec k s

Allentw n

H ac k etts

Blooms by

N ockamix

As s unC rk

Ex tonv ilLanghorn

Pember tn

Torres d l

Pier II_N

Potts v ilC res s ona

Tamaqua_

D rehers v

Virg ins v

B lueMR es

C hes trC k

Jadwin__

D y berry _

767

768

769 771

671716

676

721711

726

736746

751756

998

Boy ds SplEBrBgSpl

Spill Nodes

C rD iv SplM_BraSpl

W _BraSplC roFlSp l

Titc s SplAmw lk Spl

C rR v rSplMus c tSpl

651

EBC rotJ n

W J W W _dem

Kn48_dem

Kens _Spl

W Bra_dem

Shaft_11

Shaft_10

C rotJ nc 1

C rAq_dem

KH _D elAq KH _C atAq

KnC t_demKnD l_dem

C rotJ nc 2

N C ro_R el

N C ro_Spl

R oW B_dem

N w C r_dem

Amaw _dem

Mus c _dem

MBra_dem

Shaft_9_

Mus c ootJW. Br. Delaware R.

Es opus C k

Wallenpaupack Cr.

MongpR es

D emd_1N Y

D emd_1N J

D emd_1PA

H aleEddy

D ow ns v il

H arv ard_

Fis hEddy

D elBnD iv

Beth lehm

D emd_3PA

R iegels v

D emd_2PA

D emd_2N J

Trenton_

D emd_4PA

TT_U pD el

TT_LoD el

Below D iv

Shaft_13

term_599

Shaft_17

Sc ho_Spl

C rossR vr

Tit icus_

M_B ranch

C rotFall

A mawalk_

EAs h_Spl

W As h_Spl

Allaben_

986

R ond_Spl

983

R ond_R el

EB rB ogB r

C rot_D iv

R ondout_

993

Sc ho_LLO

WA shokan

EA shokan

Schohari

616

N York C ty

B Q_A quif

H illv iew

898

C annoSpl

897 Pepac Spl

899

N ev rs Spl

C annonsv

N evrsR es

W _B ranch

K ensico_

B oydsC or

Pepacton

W allenpa

611As hW as te

C ats k _In

Shaft_6_Shaft_5A

C helsea_

C atJ unc 1

Shaft_4_

R ondLos s

Delaware Aqueduct

C atJ _dem

Muscoot_

N ew_C rot

987

MtMarion

Model DescriptionOASIS system model combined with CEQUAL-W2 Reservoir Models

• OASIS Model used to simulate aqueduct flows and reservoir releases and spills

• Combined OASIS-W2 is backbone of Operations Support Tool (under development)

7

Model Development History

• Mid 2000s: W2 models integrated with OASIS system model for analyses of Catskill Turbidity Control Alternatives. (Hazen & Sawyer/Hydrologics/UFI)

• Late 1990s: Two Dimensional water quality models (CEQUAL-W2) developed as part of FAD modeling (UFI).

• Early 2000s: W2 models connected using linked reservoir software (UFI).

• Other Modeling Applications:• Long Term Planning• Recommendations for operating rules• Catskill Turbidity Control Program• Delaware Basin Flexible Flow Management Program (FFMP)• Climate Change Studies

• Mid 2000s: W2 model improvements including use of multiple settling rates for turbidity causing particles, improved resuspension processes and expanded historical time series. (UFI)

• Mid-Late 2000s: OASIS/W2 model used to evaluate alternatives for Catskill Turbidity Control Program. (Hazen & Sawyer/Hydrologics/UFI)

• Late 2000s-Early 2010s: Development of Operations Support Tool (OST) including the integrated OASIS/W2 model along with improved inflow forecasts and data integration. (Hazen & Sawyer/Hydrologics/UFI)

8

Reservoir Water Quality Model(CEQUAL-W2)

Meteorologic Input(Temp., RH, Solar Rad)

Flows

OASIS Water System Model

Turbidity

Reservoir Storage

Effluent Turbidity

Initial Conditions(Reservoir Water

Temperature/Turbidity Profiles; Reservoir

Storage Levels;Snowpack)

Time Series Input (Forecast)

Initial Conditions (Snapshot)

Model

Results

Model Description – Application Method

9



Flows


Turbidity

Reservoir Storage

Effluent Turbidity






Model

Results


• Current reservoir water surface elevations

• Limnological surveys• Data from automated

profiles of water column temperature and turbidity

• Snow survey results

10



Flows


Turbidity

Reservoir Storage

Effluent Turbidity






Model

Results


• Forecast based on historical record or weather service analysis• Multiple traces representing many potential future input time

series

11



Flows


Turbidity

Reservoir Storage

Effluent Turbidity






Model

Results


Multiple time series results representing each of the forecast traces

12

Model run for 57 inflow traces based on historical flow and meteorologic record (1948-2004)

Statistics of traces can be translated to cumulative probability function

Model Description – Application MethodExample of Position Analysis

13

Modeling Applications History

0

5

10

15

20

2005 2006 2007 2008 2009 2010 2011 2012 2013

# of

Mod

elin

g A

naly

ses

Year

0

5

10

15

20

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

# of

Mod

elin

g A

naly

ses

Month

Number of Modeling Analyses by Year

Number of Modeling Analyses by Month

14

Model Simulations Late February 2010• Large storm at the end of January 2010 filled

the Ashokan Reservoir and elevated turbidity in the West Basin of the reservoir.

• If another large storm event were to occur in late February, the West Basin would spill to the East Basin, creating elevated East Basin turbidity.

• A series of CEQUAL-W2 reservoir model simulations and OASIS system model simulations were performed to understand how the use of the Ashokan release channel reduces the risk of higher turbidity water in the West Basin spilling over the dividing weir and entering the East Basin.

0

4000

8000

12000

16000

1-Jan 31-Jan 2-Mar 1-Apr 1-May

Date - 2010

Flow

(cfs

)

1

10

100

1000

10000

1-Jan 31-Jan 2-Mar 1-Apr 1-May

Date - 2010

Turb

idity

(NTU

)

Esopus Creek Inflow

Esopus Creek Turbidity

Sample Analysis – Ashokan Reservoir

Esopus Creek

DividingWeir

CatskillAqueduct

ReleaseChannel

Spillway

15

1

10

100

1000

2-Feb 16-Feb 1-Mar 15-Mar 29-Mar 12-Apr 26-Apr

Date - 2010

East

Bas

in W

ithdr

awl T

urbi

dity

(N

TU)

1

10

100

1000


Date - 2010

East

Bas

in W

ithdr

awl T

urbi

dity

(N

TU)

Model Simulations Late February 2010

0

0.2

0.4

0.6

0.8

1


Date - 2010

Frac

tion

of tr

aces

with

Tu

rbid

ity >

10

NTU

on

or b

efor

e D

ate

Position Analysis Traces

Release Channel = 0 MGD

Release Channel = 350 MGD

Cumulative ProbabilityFraction of Traces with

Turbidity > 10 NTU on or before date

Eas

t B

asin

With

dra

w T

urbi

dity

(N

TU

)

Simulation Date - 2010


Release Channel = 0 MGDRelease Channel = 350 MGD

Probability of turbidity exceeding 10 NTU by end of three month simulation period reduced from near 95% to about 35%


16

0.00

0.20

0.40

0.60

0.80

1.00


Date - 2010

Fra

ctio

n o

f T

race

s w

ith

Fir

st S

pill

on

or

bef

ore

Dat

e

Model Simulations Late February 2010

Cumulative ProbabilityFirst Date of Spill from West Basin to East


Release Channel = 0 MGDRelease Channel = 350 MGD

• Using release channel significantly delays and reduces risk of spill from West Basin to East Basin.

• Delay and reduction in spill reduces risks of elevated turbidity in East Basin

• Delay and reduction in West to East Spill also reduces risk and amount of spill from East Basin.


17



Flows Turbidity

Effluent Turbidity


Temperature/Turbidity Profiles)



Model

Results


Kensico Sensitivity Model Application

18



Flows Turbidity

Effluent Turbidity





Model

Results



• Current reservoir water surface elevations

• Limnological surveys• Data from automated

profiles of water column temperature and turbidity

19



Flows Turbidity

Effluent Turbidity





Model

Results



• Forecast based on historical record or weather service analysis• Multiple traces representing many potential future input time

series

20



Flows Turbidity

Effluent Turbidity





Model

Results


Kensico Sensitivity Model ApplicationPrescribed constant time series based on expected turbidity and potential flow rates from upstream reservoirs (via aqueducts)

21



Flows Turbidity

Effluent Turbidity





Model

Results



For each combination of fixed turbidity and flow inputs the model produces multiple traces of turbidity results based on the meteorologic input traces

22

0

4000

8000

12000

16000

20000

1-Jan 2-Mar 1-May 30-Jun 29-Aug 28-Oct 27-Dec

Flow

(cfs

)

Date - 2010

0

500

1000

1500

2000

2500

1-Jan 2-Mar 1-May 30-Jun 29-Aug 28-Oct 27-Dec

Turb

idity

(N

TU)

Date - 2010

Esopus Creek Inflow

Esopus Creek Turbidity

Catskill Influent

Catskill Effluent

Delaware Effluent

Delaware Influent

• Large event in October produced large input of turbidity to Ashokan Reservoir. There was a large impact on Ashokan diversion turbidity and stop shutters were employed to reduce flow to Kensico Reservoir.

• Kensico 2D reservoir model used to determine effects of elevated turbidity and various Catskill Aqueduct flow rates on Kensico Reservoir effluent.

(20 or 40 NTU)(50, 150 or 250 MGD)

(1150, 1050 or 1000 MGD)

(1.5 NTU)

(400 MGD)

(800 MGD)

Sample Kensico AnalysisOctober 2010

23

October 2010Simulated Catskill Effluent Turbidity

20 NTU

40 NTU

These runs indicated that if Catskill influent turbidity was above 20 NTU flow rate should be reduced to 150 MGD. If Catskill influent turbidity rises to about 40 NTU for an extended period, then flow should be reduced to about 50 MGD.

Catskill Aqueduct Inflow

0.0

2.5

5.0

7.5

10.0

1-Oct 8-Oct 15-Oct 22-Oct 29-Oct0.0

2.5

5.0

7.5

10.0

1-Oct 8-Oct 15-Oct 22-Oct 29-Oct

0.0

2.5

5.0

7.5

10.0

1-Oct 8-Oct 15-Oct 22-Oct 29-Oct0.0

2.5

5.0

7.5

10.0


CatskillAqueduct Influent Turbidity

150 MGD 250 MGD

0.0

2.5

5.0

7.5

10.0


0.0

2.5

5.0

7.5

10.0


50 MGD

Sample Kensico Analysis

24

Conclusions

• Over the last decade DEP has developed and applied an extensive suite of water quality and water system models to analyze turbidity transport within the Catskill System Reservoirs.

• DEP’s water quality models have been effectively used to help inform operational decisions to minimize use of alum and turbidity at water supply intakes.

• Development and application of these models continues under the Operations Support Tool project.

Water Quality Modeling used to Inform Operational Decisions for the NYC Water Supply: A Ten Year...

Documents

Transcript of Water Quality Modeling used to Inform Operational Decisions for the NYC Water Supply: A Ten Year...