Nutrient Loading in Coastal Streams, Variation with Land Use in the

Carpinteria Valley

Timothy H. RobinsonBren School of Environmental Science and Management

University of California Santa Barbara

Introductions

Overview

Creeks of the Carpinteria Valley:

• Arroyo Paredon• CSM North Tributaries • Santa Monica• Franklin• Carpinteria/Gobernador• Lagunitas

My research project:

•Nutrient export•Modeling•Predictions

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

Methodology

Identify land use classes and sampling site locations: Chaparral/Forest, Avocado, Greenhouse, Open-Field Nursery, Residential and Commercial

Sampling strategies: Subcatchment, point discharge and above-below

Sampling methods: Manual sample or ISCO auto-sampler

GIS database development

Data analysis

Nutrient flux calculation (hydrology and stream chemistry)

Nutrient export coefficient model development

Integration with an urban growth model

Sampling Site Locations

Measuring Nutrient Concentrations

Grab samples and ISCO auto- samplers

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

Measuring Stream Flow

Staff Gauges and Pressure TransducersSurveying the Cross-Sections

Developing Rating Curves

Stream Chemistry and Hydrology

0

300

600

900

1200

10/30 10/31 11/1

Nit

rate

(µ

M)

0.6

0.8

1.0

1.2

1.4

Sta

ge

at

ou

tle

t (f

t)

outlet

commercial

residential

chaparral/forest

stage-recorded

Carpinteria Creek (WY-2002)

General Trends in Nutrient Concentrationsby Watershed

1

10

100

1000

10000

Franklin Carpinteria Santa Monica

nit

rate

(µ

M)

baseflow

stormflow

1

10

100

Franklin Carpinteria Santa Monica

ph

osp

hat

e (µ

M)

baseflow

stormflow

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

1

10

100

1000

10000

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

cum

ula

tive

exp

ort

(Km

ol)

0

50

100

150

200

250

flo

w (

cfs)

NH4 NO3 PO4

TDN flow

WY 2001

Cumulative Nutrient ExportFranklin Creek Watershed

Cumulative Nitrate ExportNursery Site

0

20

40

60

80

100

120

140

160

180

10/26 11/5 11/15 11/25 12/5 12/15 12/25

Cu

mu

lati

ve

Ex

po

rt (

Km

ol)

0

20

40

60

80

100

120

Flo

w (

cfs

)

NO3-FK07

NO3-FK06

Flow-FK07

Flow-FK06

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

WY2001 Basin Outlet Mass Flux

WY 2001

Comparison of Flux afterNormalizing with Runoff

1

10

100

Oct. 30 Nov. 29 Dec. 20

Date of Storms

Ex

po

rt (

g/h

a-m

m)

NO3-residentialNO3-commercial

NO3-greenhouse

0

1

10

100

1000

Oct. 30 Nov. 29 Dec. 20

Date of Storms

Ex

po

rt (

g/h

a-m

m)

PO4-residential

PO4-commercial

PO4-greenhouse

AAGISGISEE

IIInterviewInterview

IILiteratureLiterature

KKLiteratureLiterature

LUE tkeK

kk ttD/VD/V

LULUGISGIS

Abbreviation key:• E – Export Coefficient Function• B – Watershed Response Variable• S – Soils• P - Precipitation

Nutrient Export Coefficient Model

DKIAEL atmiiii

DDatmatm

LTERLTER

DDatmatmLiteratureLiterature

S+P +ASMCS+P +ASMC

• ASMC – Antecedent Soil Moisture Content• K – Down Stream Distance-Decay Function• k + – Coefficients• t – Time

• D – Distance Traveled Downstream• V – Average Velocity Traveled Downstream

L

Integration with an Urban Growth Model (SLEUTH)

• SLEUTH : an urban growth model implemented for the Santa Barbara area that predicts future land use, example 2050

• Enables comparison of future loadings to standards being set for stream water quality regulations (TMDLs)

• Evaluation of proposed BMP mitigations

Significance of the Project

Presentations:• PhD Seminar, Bren School UCSB• Santa Barbara Coastal LTER Seminar, UCSB• University of California Toxic Substances Research & Teaching Program, Annual Symposium, Long Beach• Coastal Water Resources, American Water Resources Association 2002 Spring Conference, New Orleans• Southern California Wetlands Recovery Project, 2002 Symposium, Ventura• California and the Worlds Oceans 02 Conference, Santa Barbara

Questions

Thank you!!

Sampling Teams

Three teams sampling in and around storm events1. Lower reach sites2. Upper reach sites3. Restricted sites

Percentage Land Use Class by Land Use Sub-Area

LU Site Area PercentCode Code (hectares) 1 2 3 4 5 6 20 50 60 Impervious*

1 GB04 1873.2 100 0 0 0 0 0 0 0 0 01 CP05 1210.2 100 0 0 0 0 0 0 0 0 02 CP02 746.9 42.1 36.2 1.3 2.3 0 3.7 12.0 0.1 2.1 7.45 CP30 6.0 0 0 0 0 100 0 0 0 0 30.06 CP20 31.9 9.2 0 0 0 0 90.8 0 0 0 77.24 FK06 80.4 11.9 20.6 4.1 47.4 0 1.5 14.5 0 0 11.43 FK04 16.9 2.9 0 97.1 0 0 0 0 0 0 68.01 SM05 901.6 100 0 0 0 0 0 0 0 0 0

* Land use codes and associated percentage of impervious surfaces**.LU-Code % Imp Class:

1 0 Undeveloped - Chaparral/Forest **2 5 Avocados - out buildings3 70 Greenhouse Small Watersheds, Technical Release 55, 4 10 Nursery Washington, DC, 19865 30 Medium density residential 2. US Army Corps of Engineers. 2000. HEC-HMS6 85 Commercial Technical Manual Hydrologic Engineering 20 10 Other agriculture Center, Davis, Ca, pp. 12350 100 Open w ater 3. Interpretation by T.H. Robinson and R.E. Beighley 60 0 Forested Riparian

% Area of Land Use (LU-Code)*:

References for percentage of impervious 1. Soil Conservation Service, Urban Hydrology for

Santa Monica Debris Basin

Gobernador Debris Basin

Chaparral/Forest Sites

Santa Monica Carpinteria Gobernador(µM) SM05 CP05 GB05NH4Min: 0* 0* 0*Max: 0.6 2.7 1.1

Average: 0.2 1.1 0.4NO3Min: 0* 1.7 0*Max: 2.0 17.0 26.9

Average: 0.5 8.4 4.5TDNMin: 0* 10.0 4.8Max: 14.9 53.5 55.5

Average: 8.6 25.0 18.1PO4Min: 0.6 0.5 0.3Max: 8.6 9.6 7.4

Average: 3.8 3.7 4.0* At or below the detection limit.

CP05

SM05

GB05

Residential Site(CP30)

Commercial Site(CP20)

Greenhouse SiteGreenhouse Site

Nursery Site(FK06+FK07)

0

5

10

15

20

25

30

35

40

45

50

10/30 10/31 11/1

Ph

os

ph

ate

(µ

M)

0.6

0.8

1.0

1.2

1.4

Sta

ge

@ o

utl

et

(ft)

outlet

commercial

residential

chaparral/forest

stage-visual

stage-recorded

Getting to Know Your Local Streams

CarpinteriaCreek

(first storm)

0

300

600

900

1200

10/30 10/31 11/1N

itra

te (

µM

)0.6

0.8

1.0

1.2

1.4

Sta

ge

at

ou

tle

t (f

t)

outlet

commercial

residential

chaparral/forest

stage-visual

stage-recorded

0

5

10

15

20

25

30

35

40

45

50

10/30 10/31 11/1

Ph

os

ph

ate

(µ

M)

0.6

0.8

1.0

1.2

1.4

Sta

ge

@ o

utl

et

(ft)

outlet

commercial

residential

chaparral/forest

stage-visual

stage-recorded

CP00 – outletCP20 – commercialCP30 – residentialGB04 – chaparral/

forest

Franklin Creek

(first storm)

0

40

80

120

160

30-Oct 31-Oct 1-Nov

Ph

osp

hat

e (µ

M)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

Sta

ge

at

ou

tle

t (f

t)

outlet

below greenhouse

greenhouse

stage - visual

stage - recorded

316 µM

0

1000

2000

3000

4000

5000

30-Oct 31-Oct 1-Nov

Nit

rate

(µM

)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

Sta

ge

at o

utl

et (

ft)

outlet

below greenhouse

greenhouse

stage - visual

stage-recorded