A Water Quality Loading Model for Tillamook Bay

1
A Water Quality Loading Model for Tillamook Bay

• Patrice A. Melancon
• Thanks to
• Dr. David Maidment
• Dr. Michael Barrett
• Dr. Francisco Olivera
• Dr. Maidments Research Group

2
Outline

• Introduction
• Problem and Objective
• Why use GIS?
• Developing the Model
• Using the Model
• Conclusions and Future Work

3
Introduction

• National Estuary Program
• Tillamook Bay

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Problem and Objective

• My work is focusing on two issues
• High Coliform loads
• High Sediment loads
• Developing a model that can serve as a Management
  Tool

5
Problem History

• Coliform contamination
• Animals confined in winter manure storage
• Liquid and solid manure applied as fertilizer
• Cow access to streams
• Sediment contamination
• Largely linked to logging practices
• Roads linked to frequent landslides

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Why Use GIS?

• Basic precept of Water Quality Modeling
• Load Flow x Concentration
• Spatial Variability
• ArcViews Hydrology Function
• Grids and Coverages

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GIS Grid Representation

• Surface divided into equal-sized cells
• Each cell has a value
• Value represents only one specific characteristic

Bay Depth Below MSL
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GIS Coverage Representation

• Surface represented as polygons, lines, or points
• Each record contains information on multiple
  characteristics

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Developing the Model

• ArcView Hydrology Functions

Flow Direction
Flow Accumulation
DEM
Accumulation in Streams
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Hydrology Model
Runoff Baseflow
Streamflow
Baseflow,B
B
Precip
Flow
Runoff,R
R
Precip
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Average Annual Rainfall
Precip, in
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Hydrology Model
RO
P
Runoff Grid
BF
Precip Grid
P
Baseflow Grid
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Event Mean Concentrations
Runoff Concentrations
0 11- 19 21 - 24 31 - 33 41 - 43 51 - 54 61 -
63 71 - 75
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Pollutant Loadings

• EMC grid x Flow grid Load grid
• Flow accumulations of flow and load grids
• Predicted pollutant concentrations

Accumulated Load
Accumulated Flow
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Using the Model

• Incorporate Effects of BMPs
• Current focus is on CAFOs
• 3 BMPs to model
• Representing spatial distribution
• Farm location vs land affected
• Use spatial average
• Analysis by subwatershed or land use

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Model Analysis
Trask River Land Use
Trask River Coliform Runoff Load

• Clip out subwatershed of interest
• Export data to analyze BMP effects or contribution

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Conclusions

• Can build effective management tool
• Effects of BMPs and relative contributions can be
  examined

18
Future Work

• More work on sediment
• Incorporate BMP effects
• Model calibration