Hudson River Watershed Sediment Transport following Tropical Storms

Irene and Lee

Gary R. Wall and Timothy F. HoffmanU.S. Geological Survey

New York Water Science Center

Mohawk River @ Cohoes 8/29/11 101,000 ft3/sec 2,200 mg/L

In cooperation with:

Kinderhook

Catskill

Mohawk Upper Hudson

Normanskill

RoJan

Rondout

Name Watershed Area (mi2)

% Above Poughkeepsie

Upper Hudson 4,616 39.4

Mohawk 3,450 29.4

Rondout 1,185 10.1

Catskill 405 3.4

Kinderhook 329 2.8

Roeliff Jansen 212 1.8

Normanskill 168 1.4

Total 10,365 88.3%

USGS Suspended-Sediment Monitoring Stations

Poughkeepsie

Kinderhook

Catskill

Mohawk Upper Hudson

Normanskill

RoJan

Rondout

Name Watershed Area (mi2)

% Above Poughkeepsie

Upper Hudson 4,616 39.4

Mohawk 3,450 29.4

Rondout 1,185 10.1

Catskill 405 3.4

Kinderhook 329 2.8

Roeliff Jansen 212 1.8

Normanskill 168 1.4

Esopus (NYCDEP)

425 3.6

Total 10,790 91.9%

USGS Suspended-Sediment Monitoring Stations

Esopus

Poughkeepsie

Methodology

• River Discharge x Sediment Concentration = Mass of sediment per unit time (Tons/day)

• Need a continuous record of both– USGS stream gages provide continuous discharge– High frequency sampling or a continuous

surrogate provide sediment concentration

Methodology• High-frequency sampling

8/27 8/30 9/2 9/5 9/8 9/11 9/140

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000Mohawk River at Cohoes

2011

Susp

ende

d Se

dim

ent C

once

ntra

tion

(mg/

L)

Methodology• Surrogate

0 0.5 1 1.5 2 2.5 30

1

2

30

1

2

3

0 1 2 3

Log 10

Sus

pend

ed S

edim

ent

Conc

entr

ation

Log10 Turbidity

Rondout Catskill

Roeliff Jansen Kinderhook

Head-of-Tide Results

Schoharie Creek

Moh

awk R

iver

Head-of-Tide Results

28-Aug 29-Aug 30-Aug 31-Aug 1-Sep0

20,000

40,000

60,000

80,000

100,000

120,000

140,000Schoharie Creek at BurtonsvilleMohawk River at Cohoes

2011

Disc

harg

e (ft

3/se

c)

2003 2004 2005 2006 2007 2008 2009 2010 Irene & Lee

-

250,000

500,000

750,000

1,000,000

1,250,000

1,500,000

1,750,000

2,000,000

Hudson River Head-of-Tide(Green Island Dam)

Upper Hudson (Waterford)Mohawk (Cohoes)

Water Year

Tons

of S

uspe

nded

Sed

imen

t

2003 2004 2005 2006 2007 2008 2009 2010 Irene & Lee

2011 -

500,000

1,000,000

1,500,000

2,000,000

2,500,000

3,000,000

Hudson River Head-of-Tide(Green Island Dam)

Upper Hudson (Waterford)Mohawk (Cohoes)

Water Year

Tons

of S

uspe

nded

Sed

imen

t

How much is 1.75 million tons of sediment?

This truck can carry 400 tons…

4,375 trucks

Bumper-to-bumper

Both directions

Cary Institute

Catskill Creek near Catskill 9/7/11 – 29,000 ft3/sec ~1,700 mg/L

8/26 8/28 8/30 9/1 9/3 9/5 9/7 9/9 9/11 9/130

5

10

15

20

25

30

2011

Rive

r Sta

ge (ft

)Lower Hudson Tributary Results

Lower Hudson Tributary Loads

Catskill

Rondout

Kinderhook

Normanskill*

Esopus

Roeliff Jansen

- 200,000 400,000 600,000

Irene and Lee Total

Tons of Suspended Sediment

* Irene only

Tributary Yields

Mohawk (Schoharie)

Catskill

Normanskill*

Kinderhook

Rondout

Roeliff Jansen

Upper Hudson

EsopusIrene and Lee Total

Suspended Sediment Yield (Tons/mi2)* Irene only

Upper Hudson

Kinde

rhook

Catskill

Esopus

Rondout

Mohawk Normanskill

RoJan

Poughkeepsie Gage

National Weather Service Radar-Based Precipitation Estimates for TS Irene

Poughkeepsie Results8/

25

8/26

8/27

8/28

8/29

8/30

8/31 9/

1

9/2

9/30

123456789

Wat

er Le

vel (

feet

)

8/20 8/30 9/9 9/19 9/29 10/9 10/19 10/290

50100150200250300350400

HRECOS - Norrie PointCaryUSGS

2011

Conc

entr

ation

/Tur

bidi

ty

0.5 1 1.5 2 2.5 30.5

1

1.5

2

2.5

3

Cary I...

Log10 TurbidityLo

g10

Conc

entr

ation

Institute

8/26 8/30 9/3 9/7 9/11 9/15 9/19 9/23 9/270

100

200

300

400

500

600

700

-50,000

0

50,000

100,000

150,000

200,000

250,000

300,000

2011

Susp

ende

d Se

dim

ent C

once

ntra

tion

(mg/

L)

Net

Dis

char

ge (ft

3/se

c)

Poughkeepsie Results

Concentration x Discharge = 1 million tons of suspended sediment through mid-October 2011

Green Island Dam

900,000 tons95,000 tons

1 milliontons

West-of-Hudsontributaries

East-of-Hudson tributaries

Poughkeepsie

~1.75 milliontons trapped

1.75 milliontons

Hudson River near Poughkeepsie 8/30/11Net Discharge = 170,000 ft3/sec , 248mg/L

Acknowledgements:• DEC Hudson River Estuary Program and Div. of Water• EPA Harbor Estuary Program• NEIWPCC• Stuart Findlay – Cary Institute• Randy Alstadt – City of Poughkeepsie• Hudson River Foundation• HRECOS• National Weather Service