Small Tributary Loads

The “Guadalupe River Study”

Lester McKee, John Oram, Jon Leatherbarrow SFEI

Autumn Bonnoma, Mark Stephenson, Wes Heim

MLML

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Sampling Location

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Sampling

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Suspended Sediment Loads

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

2003 2004 2005

Water Year

Su

spen

ded

Sed

imen

t L

oad

(t)

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HgT v SSC (all data)

1

10

100

1,000

10,000

100,000

1 10 100 1,000 10,000

Suspended Sediment (mg/L)

To

tal M

ercu

ry (

ng

/L)

WY 2003

WY 2004

WY 2005

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Sources of Mercury

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HgTmg/kg (ppm)

Total Mercury Loads

0

20

40

60

80

100

120

140

160

180

2003 2004 2005

Water Year

To

tal M

ercu

ry (

kg)

111% MAQ 96% MAQ 133% MAQ

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Methylmercury Concentrations

0.0

0.5

1.0

1.5

2.0

0 100 200 300 400 500 600 700 800

Suspended Sediment (mg/L)

To

tal M

eth

ylm

ercu

ry (

ng

/L)

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Methyl Mercury Loads

40 g or 0.5% of total Hg load

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Bedload Mercury Concentrations

0

0.5

1

1.5

2>3

.8

>2.0

>1.0

>0.5

>0.2

5

>0.1

25

>0.0

625

< 0.

0625

Grain size (mm)

To

tal m

ercu

ry (

mg

/kg

)

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Bedload Mercury Loads

1% of total Hg load

Grainsize(mm)

<0.5 <1 <2 <4 <8 <16 <32 <64 Total

Percent Finer Than (%) 1 6 15 31 51 75 98 100

Bed Load Sediment Transport (t) 17 83 150 258 333 399 391 33 1,663

Mercury (mg/kg) 0.42 0.24 0.094 0.058 0.029 0.029 0.029 0.029

Bed Load Mercury Transport (g) 7 20 14 15 9 11 11 1 88

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WY05 Organic Contaminants Concentrations

Range FWMC

WY 2003 3.4 – 90 ng/l 55 ng/l

WY 2004 0.7 – 66 ng/l 26 ng/l

tPBDEs = 2 to 3 x tPCBs

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Organic Contaminants Loads

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WY

200

3W

Y 2

004

WY

200

5Discharge SSC

53.1 Mm3

45.3 Mm3

58.0 Mm3

10,805 tons

8,578 tons

4,575 tons

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tPCBs vs. SSC

WY 2005 samples showed increased separation between rising and falling stages

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Rising and Falling Stages

tPCBs tPBDEs

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Project Schedule WY 2005

Report completed read for review

WY 2006 funded by USACE/SCVWD / RMP Complete QAQC for all WYs and get the data on the WWW Write papers for Journal

WY 2007 funded? Only WY 2006 currently guaranteed but everything in place for

continuation RMP funding not yet discussed

Future Modeling (if funding is found)? Explore transport processes in more detail Explore and predict the effects of management on Hg loads

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