UC Marine CouncilUC Marine Council Santa Barbara Coastal LTER - NSF

Nutrient Export Coefficient Modeling in Nutrient Export Coefficient Modeling in Mediterranean Coastal StreamsMediterranean Coastal Streams

Timothy H. Robinson, Al Leydecker, Arturo A. Keller and John M. MelackTimothy H. Robinson, Al Leydecker, Arturo A. Keller and John M. MelackBren School of Environmental Science & ManagementBren School of Environmental Science & Management

University of California, Santa Barbara, USAUniversity of California, Santa Barbara, USA

Watersheds Drainage Area Max-Elevation Ave-Slope Urban Agriculture Chaparral/Forest

(km2) (m) (ft) (%) (%) (%) (%)Carpinteria 39.2 1424 4672 38 2 11 85

Franklin 11.6 533 1749 20 29 30 40Santa Monica 9.8 1192 3911 45 3 3 93

Watershed CharacteristicsWatershed Characteristics StudyArea

LA

SF

Climatic Regime

0

5

10

15

20

25

Sept

OctNov

Dec Jan

Feb Mar

AprM

ayJu

nJu

lAug

Avg

Mo

nth

ly P

reci

pit

atio

n,

cm Downtown Santa Barbara, 30 mSan Marcos Pass, 671 m

0

50

100

150

200

250

1955 1960 1965 1970 1975 1980 1985 1990 1995 2000

An

nu

al

Ra

infa

ll,

cm

Downtown Santa Barbara, 30 mSan Marcos Pass, 671 m

Analyzing for: Ammonium (NH4

+), Nitrate (NO3-), Total Dissolve

Nitrogen (TDN), Phosphate (PO43-), Total Particulate

Carbon (TPC), Total Particulate Nitrogen (TPN), Total Particulate Phosphate (TPP), Total Suspended Sediments (TSS) and major ions at selected locations

Specifics:

Frequency: • Regular sampling:

Once every 2 weeks during the dry seasonOnce a week during the wet season

• Storm sampling:Every hour on the rising limb of the hydrographEvery 2-4 hours on the falling limb of the hydrograph

Project duration: WY2001, WY2002 and WY2003

Annual Basin Nutrient ExportWater Year 2001 and 2002

0

2

4

6

8

10

Franklin Carpinteria Santa Monica

Nit

rate

Exp

ort

(kg

-N h

a-1yr

-1)

20012002

0.0

0.5

1.0

1.5

Franklin Carpinteria Santa Monica

Ph

os

ph

ate

Ex

po

rt (

kg

-P h

a-1

yr-1

) 2001

2002

0

2

4

6

8

Franklin Carpinteria Santa Monica

PO

N E

xp

ort

(k

g-N

ha

-1y

r-1)

20012002

0

5

10

15

20

25

Franklin Carpinteria Santa Monica

An

nu

al D

isc

ha

rge

(c

m y

r-1)

2001

2002

Abbreviation key:• L – Nutrient Export (loss) (mass area-1 time-1)• E – Export Coefficient Function• – Watershed Response Variable• LU – Land use• S – Soils

Nutrient Export Coefficient ModelNutrient Export Coefficient Model(NEC-M)(NEC-M)

• P – Precipitation • A – Land Use Area • I – Nutrient input rate• K – Down Stream Distance-Decay Function• k and – Coefficients

• t – Time• d – Distance Traveled Downstream • v – Average Velocity Traveled Downstream• Datm – Atmospheric deposition

AAGISGISEE

IIInterviewInterview

IILiteratureLiterature

KKLiteratureLiterature

)(LUE tkeK

kk ttd/vd/v

LULUGISGIS

DKIAEL atmiiii

DDatmatm

LTERLTER

DDatmatmLiteratureLiterature

S+PS+P

L

Sampling Site Locations

WY2001WY2002WY2003

Land Use:•Chaparral/Forest•Avocado•Greenhouse•Nursery•Residential•Commercial

Spatial Extent of Land Use Class (A)

Land Use Area % Target % Secondary % Impervious

# Class (hectares) Land Use Land Use Surface

1 Chaparral/Forest 1873 100 0 0

1 Chaparral/Forest 1210 100 0 0

1 Chaparral/Forest 902 100 0 0

2 Avocado 747 36 42 (Chap/For) 7

3 Greenhouse 17 97 3 (Chap/For) 68

4 Nursery 80 47 21 (Avo) / 12 (Chap/For) 11

5 Residential 6 100 0 30

6 Commercial 32 91 9 (Chap/For) 77

6

Nutrient Export WY2002

Hourly time-step Hydrology:

• Pressure Transducer• Observed stage• HEC-RAS

Stream Chemistry Modeling

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

9/16 12/25 4/4 7/13 10/21

Cu

mu

lati

ve E

xpo

rt (

kmo

ls)

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

Flo

w (

m3 s-1

)

NH4

NO3

PO4

flow

Chaparral/Forest

E – Export Coefficient Function – Watershed Response VariableS – SoilsP – Precipitation

Nutrient Export Coefficient (E)Nutrient Export Coefficient (E)

EE

LUE LULUGISGIS S+P S+P

0

500

1000

1500

2000

2500

Franklin Carpinteria Santa Monica

nit

rate

(µM

)

baseflow

stormflow

0

10

20

30

40

50

Franklin Carpinteria Santa Monica

ph

osp

hat

e (S

RP

, µM

)

baseflow

stormflow

1

10

100

1000

10000

5-Jan 15-Jan 25-Jan 4-Feb 14-Feb 24-Feb 6-Mar

cu

mu

lati

ve

ex

po

rt(k

mo

l)

0

1

2

3

4

5

6

7

8

dis

ch

arg

e (

m3

s-1)

flow

TDN

NO3

PO4

NH4

WY 2001 Franklin Creek

Scaling the Export Coefficient ()

• Storm to Storm relationships.

• Volume Weighted Mean Concentrations vs. Cumulative Rainfall.

• Volume Weighted Mean Concentrations vs. Rainfall/Runoff Ratio.

• Topographic Index (TI): variable source area.

• Antecedent Soil Moisture Content: SSURGO soils data, texture->porosity, infiltration rates, evapotranspiration rates, depth to impervious layer, etc.

Nutrient Flux (normalized by runoff)

0.01

0.1

1

10

100

1000

10000

10/30 11/12 11/24 11/29 12/2 12/14 12/20 12/30 1/27 2/17 3/7 5/20

NO

3 E

xpo

rt (

g h

a-1m

m-1)

NO3-Commercial

NO3-Residential

NO3-Greenhouse

NO3-Chaparral/Forest

WY2002

y = 227.45Ln(x) + 1046.6

R 2 = 0.52

y = -91.22Ln(x) + 114.48

R 2 = 0.71

0

500

1000

1500

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

Runoff/Rainfall Ratio

VW

M C

on

ce

ntr

ati

on

(µ

M)

NO3

PO4

Greenhouse

VWM vs. Runoff/RainfallVWM vs. Runoff/Rainfall

Conclusions

• High frequency storm sampling is critical.

• Nutrient Export Coefficients in Mediterranean climates must be a function that is related to the watershed runoff response and not a single annual term.

• Analysis of the final year of data will solidify scaling techniques in NEC-M.

• Future work: implement the model in the study watersheds and test its portability in a catchment outside of the area (e.g. Spain).

QuestionsQuestions

Thank you !Thank you !

Nutrient Watershed Flux

0

2,000

4,000

6,000

8,000

10,000

12,000

Santa Monica Franklin Carpinteria

Nu

trie

nt

Lo

adin

g (

kg/y

r)

NH4-N

NO3-N

DON-N

PO4-P

Linkage – Stream Network & Chemistry

Arc Hydro Geodatabase: geometric network representation of the connectivity of surface water

• HydroNetwork• HydroEdge• HydroJunctions• SchematicLinks+Nodes• HydroPointEvent• HydroLineEvent

NH4 NO3 PO4

Location ID LTER # date time uM uM uMCarpinteria @ Calle Ocho CP00 30001 3-Oct-02 18:50 2.8 257.8 1.9Carpinteria @ Vedder's CP05 30002 3-Oct-02 12:20 0.5 26.3 3.4Carpinteria @ 6 St. manhole CP20 30003 3-Oct-02 19:10 1.7 139.3 3.6Carpinteria @ Casitas Village drain CP30 30004 3-Oct-02 18:40 114.0 0.7 187.5Franklin @ Carpinteria Ave FK00 30005 3-Oct-02 20:05 5.2 1712.9 6.0Franklin @ Meadow View ramp FK03 30006 3-Oct-02 19:50 0.7 2227.2 2.9Franklin @ Meadow View drain FK04 30007 3-Oct-02 19:55 5.3 666.7 125.5Franklin @ Girls Club on Foothill FK06 30008 3-Oct-02 19:40 1.0 2180.7 1.1

Drainage Network + Sampling Points

Visual Basic for Application:MS Excel/Access:

DEM analysis

Measuring Stream Flow

Staff Gauges and Pressure TransducersSurveying the Cross-Sections

Developing Rating Curves

Nutrient LoadingDevelopment of a Nutrient Flux Model

StreamChemistry

ObservedStage

PTStage

(5-min)

ObservedFlow

PTFlow

(5-min)

StreamChemistry

Stage-Discharge Relationship(HEC-RAS)

Flow(hourly)Flow

(hourly)

StreamChemistry(hourly)

Identify: Baseflow, Peakflow..

Nut. Conc.

Flow(hourly)

StreamChemistry

(model/obs)

Nut. Flux(conc/flow)

AnnualAnnualNutrient LoadingNutrient Loading

ObservedFlow

(hourly)

Linear extrapolation

Precipitation WY2002

Cumulative Storm Storm Rainfall Rainfall Duration(date) (mm) (hours)10/30 10.2 711/12 45.7* 3811/24 40.6 411/29 10.2 1012/2 7.6 512/14 5.1 312/20 10.2 612/30 22.9* 341/27 12.7 52/17 10.2 153/7 5.1 65/20 5.1 2

* Two short pulses during the time period.

Nutrient Flux (normalized by runoff)

0.1

1

10

100

1000

10/30 11/12 11/24 11/29 12/2 12/14 12/20 12/30 1/27 2/17 3/7 5/20

PO

4 E

xpo

rt (

g h

a-1m

m-1)

PO4-Commercial

PO4-Residential

PO4-Greenhouse

PO4-Chaparral/Forest

WY2002

Attenuation (K)Attenuation (K)

KKLiteratureLiterature

tkeK

kk ttD/VD/V

• Distance from stream • Distance from basin outlet• Type of riparian corridor• Dispersal Area and Trapping

Likelihood (BI Index)

VWM vs. Cumulative RainfallVWM vs. Cumulative RainfallVWM - Volume Weighted Mean

Trendline for NO3y = 3.9245x + 463.75

R2 = 0.42

0

500

1000

1500

0 20 40 60 80 100 120 140 160 180 200

Cumulative Rainfall (mm)

VW

M C

on

ce

ntr

ati

on

(µ

M) NO3

PO4

Greenhouse

VWM vs. Cumulative RainfallVWM vs. Cumulative Rainfall

R 2 = 0.38

0

20

40

60

80

100

0 20 40 60 80 100 120 140 160 180 200

Cumulative Rainfall (mm)

VW

M C

on

ce

ntr

ati

on

(µ

M) NO3

PO4

Residential

0

500

1000

1500

0 20 40 60 80 100 120 140 160 180 200

VWM - Volume Weighted Mean

VWM vs. Runoff/RainfallVWM vs. Runoff/Rainfall

y = 0.1293x -0.7348

R 2 = 0.5155

0

5

10

15

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08

Runoff/Rainfall Ratio

VW

M C

on

ce

ntr

ati

on

(µ

M)

NO3

PO4

Chaparral/Forest