Nutrient%20Concentrations%20in%20Coastal%20Streams,%20Variation%20with%20Land%20Use%20in%20the%20Carpinteria%20Valley%20(Santa%20Barbara%20Coastal%20LTER)

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Nutrient Concentrations in Coastal Streams,
Variation with Land Use in the Carpinteria Valley
(Santa Barbara Coastal LTER)
Timothy H. Robinson John M. Melack Arturo A.
Keller Bren School of Environmental Science and
Management University of California Santa Barbara
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Outline of the talk
Project overview Sampling strategy and
location Measuring stream nutrient concentrations
and flow Nutrient loading and the development of
a flux model Basin outlet mass flux Comparison
of nutrient loading by land use type Nutrient
export coefficient modeling Integration with an
urban growth model
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Project Overview
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(No Transcript)
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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
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Sampling Site Locations
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Measuring Nutrient Concentrations
Grab samples and ISCO auto- samplers
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Specifics

• 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
• Frequency
• Regular sampling
• Once a week during the wet season
• Once every 2 weeks during the dry season
• Storm sampling
• Every hour on the rising limb of the hydrograph
• Every 2-4 hours on the falling limb of the
  hydrograph

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Measuring Stream Flow
Staff Gauges and Pressure Transducers Surveying
the Cross-Sections Developing Rating Curves
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(No Transcript)
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Stream Chemistry and Hydrology
Carpinteria Creek (WY-2002)
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General Trends in Nutrient Concentrations by
Watershed
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Nutrient Loading Development of a Nutrient Flux
Model
Stream Chemistry
Observed Stage
PT Stage (5-min)
Stage-Discharge Relationship (HEC-RAS)
Observed Flow
PT Flow (5-min)
Stream Chemistry
Flow (hourly)
Flow (hourly)
Stream Chemistry (hourly)
Observed Flow (hourly)
Identify Baseflow, Peakflow.. Nut. Conc.
Flow (hourly)
Stream Chemistry (model/obs)
Linear extrapolation
Annual Nutrient Loading
Nut. Flux (conc/flow)
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Modeled vs. Observed
Residential - CP30
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Cumulative Nitrate ExportNursery Site
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Basin Nutrient Export Franklin Creek Watershed
WY 2001
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WY2001 Basin Outlet Mass Flux
WY 2001
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Comparison of Flux afterNormalizing with Runoff
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Nutrient Export Coefficient Model
A GIS
E
I Interview
I Literature
K Literature
Datm LTER
Datm Literature
L
k
a
t D/V
LU GIS

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

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

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

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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

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Conclusions

• Stream nutrient concentrations only partially
  tell the story
• Hydrology is the critical element of any flux
  calculation, which is necessary
• to characterize nutrient loading
• The finer the sampling strategy the better the
  results, particularly with urban/agriculturally
  dominated sites
• Creating a dedicated and enthusiastic group of
  stream samplers is a crucial component of any
  project of this nature
• Nutrient export coefficients for a Mediterranean
  climate need to accommodate the high
  inter/intra-year storm variability
• A minimum of two years of data are needed to
  statistically validate model results
• Hope for rain!!

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Questions
Thank you