Status, Trends, Distribution, Status, Trends, Distribution, and Functions of Wetlands and Functions of Wetlands in the New York City Water in the New York City Water

Supply WatershedSupply WatershedLaurie Machung, Bureau of Water Supply,

Watershed Protection and Planning

Mapping and Research ProgramsMapping and Research Programs

National Wetlands InventoryNational Wetlands Inventory Wetlands Status and TrendsWetlands Status and Trends Wetland Characterization and Preliminary Wetland Characterization and Preliminary

Functional AssessmentFunctional Assessment Reference Wetlands Monitoring ProgramReference Wetlands Monitoring Program

National Wetlands Inventory (NWI)National Wetlands Inventory (NWI)

USFWS first completed in 1996 using 1:58,000 USFWS first completed in 1996 using 1:58,000 scale mid 1980’s aerial photographyscale mid 1980’s aerial photography

Updated in 2005 using 1:40,000 scale 2003 and Updated in 2005 using 1:40,000 scale 2003 and 2004 aerial photography2004 aerial photography

Provides base data on the distribution, Provides base data on the distribution, characteristics, and extent of wetlandscharacteristics, and extent of wetlands

Wetland Status and TrendsWetland Status and Trends

Completed for the Croton Watershed in 1999, Completed for the Croton Watershed in 1999, updated in 2005updated in 2005

1968 – 19841968 – 1984 1984 – 19941984 – 1994 1994 – 20041994 – 2004

Completed for Catskill and Delaware 12/08Completed for Catskill and Delaware 12/08 Mid 80’s – mid 90’sMid 80’s – mid 90’s Mid 90’s – 2004Mid 90’s – 2004

Wetland CharacterizationWetland Characterization• USFWS added LLW codes to each wetland polygon in

the NWI database to depict:

•Landscape Position•Lotic•Lentic•Terrene

•Landform

•Water flow path•Throughflow•Outflow•Isolated

•Other modifiers (hw)

Wetlands Monitoring Program:Wetlands Monitoring Program:

• East of Hudson – 6 reference sites

•West of Hudson – 22 reference sites

•Water Quality

•Water Table

•Vegetation

•Soils

Catskill/Delaware Reference WetlandsCatskill/Delaware Reference Wetlands

Croton Watershed Croton Watershed Palustrine WetlandsPalustrine Wetlands

Approximately 15,355 acres (6% of land surface)

0 2000 4000 6000 8000 10000 12000

Emergent

Scrub-shrub

Forested

Ponds/beds/shores

acres

Catskill/Delaware Watersheds Catskill/Delaware Watersheds Palustrine WetlandsPalustrine Wetlands

Approximately 9,565 acres (1% of land surface)

0 500 1000 1500 2000 2500 3000 3500

Emergent

Scrub-shrub

Forested

Ponds/beds/shores

acres

NWI vs. Delineated Area Site NWI area (acres)

GPS area (acres)

% depcited on NWI

FAHN 14.3 16.8 85.1BBUCK 3.9 6.7 58.2YALE 2.4 6.6 36.4NIN 7.9 11.4 69.3

SUM E.O.H. 28.5 41.5 68.7

SFB 0.6 3.4 17.0

AWW 1.7 3.0 55.8

ADT 2.0 3.1 62.9

SMS 2.5 5.1 48.7

CSB 3.1 5.6 55.3

AMH 4.8 8.2 59.3

SUB 5.3 14.8 36.0

ART 5.8 7.4 78.3

PHH 7.1 4.8 147.0

ACB 8.1 7.5 108.6

NAB 8.3 13.3 62.1

ARW 9.8 12.9 76.1

NMR 11.5 9.8 117.4

NTD * 0.4 *

APP * 0.6 *

AAR * 0.7 *

CLS * 1.2 *

NWD * 1.6 *

NGC * 2.1 *

SMK * 3.8 *

NMM * 8.0 *

SUM W.O.H. 70.6 117.4 60.1

Wetland Trends: East and West of Hudson Wetland Trends: East and West of Hudson WatershedsWatersheds

-146.3

-42.99 -3.1

126.45

70.8852.5

-200

-100

0

100

200

300

400

500

600

1968-1984 1984-1994 1994-2004

Croton Croton Croton

net

acr

es net w etland

net pond

-96.4

4.6

515

110

-200

-100

0

100

200

300

400

500

600

1984-1994 1994-2004

Cat/Del Cat/Del

net

acr

es

0

5

10

15

20

25

30

35

40

45

50

Terrene Loticheadwater

Lotic main Pond Lentic

Per

cen

t o

f W

etla

nd

s

West

East

Wetland Landscape Positions in East and West of Hudson Watersheds

Wetland CharacterizationWetland Characterization

•Describes Wetland landscape settings

•Enables an estimate of wetlands potentially lacking federal regulatory protection

•SWANCC•Isolated wetlands

•Rapanos and Carabel •Significant nexus analysis required for Non-navigable, non-relatively permanent tributaries and adjacent wetlands•To determine if they significantly affect the chemical, physical, and biological integrity of TNWs

Wetland CharacterizationWetland Characterization Used USFWS LLW codes to estimate Used USFWS LLW codes to estimate

abundance of wetlands lacking abundance of wetlands lacking perennial connectionsperennial connections

Two approachesTwo approaches Water Flow path modifiersWater Flow path modifiers

• IS, IN = isolatedIS, IN = isolated• OI, TI, OU = intermittentOI, TI, OU = intermittent

Headwater modifiersHeadwater modifiers• IN and IS = isolatedIN and IS = isolated• Headwater modifier - 1Headwater modifier - 1stst and 2 and 2ndnd order streams order streams

Croton Watershed

Flow Path Method

Predicts that 24% of wetlands are ‘vulnerable’

isolated (5%)

intermittently connected (19%)

Croton Watershed

Headwater Method

Predicts that 43% of wetlands are ‘vulnerable’

Headwaters 38%

Isolated 5%

Catskill/Delaware Watersheds

Flow Path Method

Predicts that 38% of wetlands are vulnerable

isolated (13%)

intermittently connected (25%)

Catskill/Delaware Watersheds

Headwater Method

Predicts that 71% of wetlands are ‘vulnerable’

Headwaters (58%)

Isolated (13%)

NWI Wetlands

0.00

2000.00

4000.00

6000.00

8000.00

10000.00

12000.00

14000.00

16000.00

E.O.H. W.O.H.

Acr

es Non-DEC regulated

DEC Regulated

Proportion of NWI Wetlands not Proportion of NWI Wetlands not included on NYS FWW Mapsincluded on NYS FWW Maps

21%

68%

Percent of Non-DEC wetlands without Percent of Non-DEC wetlands without perennial connections perennial connections

Non-DEC Regulated Wetlands

0

1000

2000

3000

4000

5000

6000

7000

EOH fp EOH hw WOH fp WOH hw

Acr

es Federally vulnerable

Federally protected52%

70%

40% 68%

(11%) (15%) (27%) (46%)

DOC ExportDOC Export

L L W W

DO

C(m

g/L

)

W e s t o f H u d s o n

2 .0 3 8 6 1 .3 7 8 2 1 .0 6 7 92 .0 3 8 6 1 .3 7 8 2 1 .0 6 7 9

TE L Sh w L S-5

0

5

1 0

1 5

2 0

2 5

3 0

3 5

Ea s t o f H u d s o n

9 .2 7 1 0

5 .5 0 5

9 .2 7 1 0

5 .5 0 5

TE L Sh w L S

D is tric t: W D OC (m g /L ): KW -H (2 ,2 6 0 ) = 1 3 .7 1 2 4 , p = 0 .0 0 1 1D is tric t: E D OC (m g /L ): KW -H (2 ,4 8 4 ) = 1 2 7 .8 6 9 2 , p = 0 0 .0 0 0 0

DOC ExportDOC Export

FAHNPBALL

BBUCKYALE

NINOUT

PCPOUT

-20 0 20 40 60 80 100 120 140 160 180 200 220

Wetland acres in drainage basin

-5000

0

5000

10000

15000

20000

25000

30000

35000

Wetlandacres:DOC kg/yr1: r = 0.9935, p = 0.00006 Wetlandacres:DOC kg/yr2: r = 0.9817, p = 0.0005

DOC kg/yr1 DOC kg/yr2

1 .4 63 .8 3

6 .1 98 .6 1

1 1 .0 01 3 .4 0

1 6 .0 01 8 .5 0

2 0 .9 02 4 .2 0

2 6 .8 02 9 .7 0

D OC (m g /L )

1 0

4 0

7 0

1 0 0

1 3 0

1 8 0

2 3 0

3 0 0

3 5 0

Co

lorv (p

t/co)

r = 0 .9 2 3 8 , p = 0 0 .0 0 0 0

DOC vs Color: East of Hudson Wetland Outflows

ConclusionsConclusions According to the NWI, Wetlands occupyAccording to the NWI, Wetlands occupy

15,355 acres, or 6% of Croton Watershed15,355 acres, or 6% of Croton Watershed 9,565 acres, or 1% of the Catskill and Delaware 9,565 acres, or 1% of the Catskill and Delaware

WatershedsWatersheds Reference Wetland monitoring identified Reference Wetland monitoring identified

margin of error in NWI mappingmargin of error in NWI mapping Net rates of wetland loss have declined over Net rates of wetland loss have declined over

the time periods studiedthe time periods studied Pond construction was leading cause of Pond construction was leading cause of

wetland loss in all time periods, though rates wetland loss in all time periods, though rates have declinedhave declined

ConclusionsConclusions

Based USFWS LLW modifiers, an Based USFWS LLW modifiers, an estimatedestimated 24% to 43% of Croton Watershed Wetlands 24% to 43% of Croton Watershed Wetlands

and 38% to 71% of Catskill/Delaware and 38% to 71% of Catskill/Delaware Wetlands could lose federal protection and;Wetlands could lose federal protection and;

11% to 15% of Croton Wetlands 11% to 15% of Croton Wetlands and 27% to 46% of Catskill/Delaware and 27% to 46% of Catskill/Delaware wetlands would lack federal or state wetlands would lack federal or state protectionprotection

ConclusionsConclusions

Reference wetland monitoring is a Reference wetland monitoring is a valuable tool to assess whether wetlands valuable tool to assess whether wetlands have a nexus to traditional navigable have a nexus to traditional navigable waterswaters