Seminar:Snowmelt and Storm Events:

Biogeochemical and Hydrological Responses

Why study: Snowmelt and Storm Events

• Provide information on physical and chemical attributes of catchments

• Important contributor to discharge and biogeochemical fluxes

• Events can have a major influence on physical, chemical and biological attributes of surface waters.

Storm Event Example

Inamdar, S., P., S. F. Christopher, and M. J. Mitchell. 2003. Export mechanisms for dissolved organic carbon and nitrate during summer storm events in a glaciated forested catchment in New York, USA. Hydrological Processes (In Press).

540

634

Arbutus Lake

H-Flume

X580 m

Scale

0 0.5 km

Contour interval 30 m

X

X

570 m

630 m

748 m

634 m

G14S1

Peatland with groundwaterelevation well

Wetlands/Peatlands

StreamsGroundwater sampling well

S2

Instrumented hillslope with lysimeters & throughfall collectors

N

The Archer Creek catchment and instrumentation

Arbutus Watershed

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

9/16 9/18 9/20 9/22 9/24

Date

dis

cha

rge

(m

m/h

r)

0

50

100

150

200

250

300

350

calc

ium

(u

eq

/L)

discharge calcium

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

9/16 9/18 9/20 9/22 9/24

Date

dis

cha

rge

(m

m/h

r)

0

10

20

30

40

50

60

70

80

90

100

ma

gn

esi

um

(u

eq

/L)

discharge magnesium

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

9/16 9/18 9/20 9/22 9/24

Date

dis

cha

rge

(m

m/h

r)

0

5

10

15

20

25

30

35

nitr

ate

(u

eq

/L)

dischargenitrate

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

9/16 9/18 9/20 9/22 9/24

Date

dis

cha

rge

(m

m/h

r)

0

200

400

600

800

1000

1200

1400

1600

1800

DO

C (

um

ol/L

)

dischargedoc

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

9/16/99 9/18/99 9/20/99 9/22/99 9/24/99

date

dis

cha

rge

(m

m/h

r)

0

1

2

3

4

5

6

7

8

pre

cip

(m

m/h

r)

dischargeprecip

(a)

(b) (c)

(d) (e)

Precipitation, streamflow, and solute concentrations for the Floyd storm events.

soil reservoir

till reservoir

STAGE 1 STAGE 2

STAGE 3 STAGE 4

DOC

nitrate

discharge

soil reservoir

till reservoir

STAGE 1 STAGE 2

STAGE 3 STAGE 4

DOC

nitrate

discharge

DOC

nitrate

discharge

Perceptual model for NO3-

and DOC evolution considering water and solute contributions from deep and near-surface flow paths and spatial connectedness of saturated areas. Note: Arrow on the hydrograph (inset) indicates position of the stage during the event.

Snowmelt Example

Piatek, K.B., M.J. Mitchell, S.R. Silva and C. Kendall. 2003. Sources of nitrate in

Adirondack surface water during dissimilar snowmelt events. (In review).

Pre

cip

itat

ion

(m

m d

ay-1

)

0

10

20

30

40

50

Time

Jan Feb Mar Apr May Jun Jul

0

10

20

30

40

50 2002

2001

Dis

char

ge

(mm

day

-1)

0

5

10

15

20

25

30

35

2001 2002

Sn

ow

Dep

th (

cm)

0

20

40

60

80

100

120

NO

3- (

mo

l L-1

)0

20

40

60

80

To

tal

Al (

mo

l L-1

)

02468

10D

OC

(m

ol C

L-1

)

0

500

1000

1500

2001

Jan Feb Mar Apr May Jun Jul

Dis

char

ge

(mm

day

-1)

0

10

20

30

NO

3- (

mo

l L-1

)0

20

40

60

80

To

tal A

l (m

ol L

-1)

02468

10

DO

C (

mo

l C L

-1)

0

500

1000

1500

2002

Jan Feb Mar Apr May Jun Jul

Dis

cha

rge

(mm

day

-1)

0

10

20

30

Terminology

• Changes in isotopic abundance are expressed as ratios of 15N/14N of sample to air or 18O/16O of sample to ocean water.

• Units: per mil (o/oo)

δδ1515NNxx = {[( = {[(1515N/N/1414N)N)xx / ( / (1515N/N/1414N)]N)]airair –1} * 1000 –1} * 1000

δδ1818OOxx = {[( = {[(1818O/O/1616O)O)xx / ( / (1818O/O/1616O)]O)]stdstd –1} * 1000 –1} * 1000

Separation of nitrate sources using stable isotopes of nitrogen and oxygen

• Nitrate has different stable isotopic values.

• Atmospheric N-nitrate has 18-O values than N-nitrate derived from soil and ground waters.

-10

0

10

20

30

40

50

60

70

-10 0 10 20 30Delta 15N (o/oo)

De

lta

18O

(o/ o

o)

precipitation

Soil + groundwater

General trends of 18-O and 15-N values of nitrate

-10

10

30

50

70

90

-10 -8 -6 -4 -2 0 2 4 6

Delta 15N (o/oo)

De

lta

18O

(o/ o

o)

2001

2002

precipitation

groundwater

Results of nitrate samples taken during snowmelt at Archer Creek Catchment, Huntington Forest

Episodic Acidification

Mitchell, M.J. Episodic Acidification. In: Jay H. Lehr (ed). Encyclopedia of Water. John Wiley and Sons Publishing (In Press).

Biscuit BrookCatskill MountainsNew York

Goals of Seminar

• Increase understanding of biogeochemical and hydrological responses of snowmelt and storm events

• Exploration of literature on hydrology and biogeochemistry

• Develop skills for oral presentations and discussions

• Prepare for workshop to be held on Feb. 27, 2003 on “Snowmelt and Storm Events: Biogeochemical and Hydrological Responses”