1. Emma Gildesgame, Katie Lebling and Ian McCullough
Watershed/GIS
Emma Gildesgame, Katie Lebling and Ian McCullough

2. What is GIS? Geographic Information System ArcGIS 9.3.1 Manny Gimond
ArcMap
ArcCatalog
Manny Gimond
Master of GIS

3. What does GIS do? Map generation Spatial analysis
Data storage and organization
Modeling

4. GIS maps consist of multiple layers

5. Types of Datasets
Vector (feature)
Point
Polyline
Polygon

6. Attribute Tables
Layers have attributes, which are basically data attached to each layer
Each polygon can have several fields (columns)

7. Types of Datasets Raster Made of pixels
Each pixel has a numerical value
Cell size (resolution) can be adjusted

8. Types of Datasets Image files Digital orthophotoquad
(for land use digitizing)
Scanned Oakland tax map (jpg)

9. GIS in BI493
Present data in a way that can be understood by a wide range of audiences
Numerical data
Spatial information

10. Models to be Generated Erosion potential Erosion impact
Septic suitability
Development impact
Phosphorus loading

11. Erosion Potential Why: Erosion prevention
Data: Soil type, slope, land use
From: ME GIS, NAIP, NRCS

12. Erosion Impact Why: future development, incl. lots away from shoreline
Data: Erosion potential evaluated as a function of distance from lake

13. Septic Suitability
Why: quality of existing septic systems, planning for future construction
Data: Slope, K-factor
From: ME GIS, NRCS

14. Development Impact
Why: determine effects of future development on the lake
Data: Assessment cards, soil, slope, land use, water proximity
From: Towns of Belgrade and Oakland, ME Office of GIS, NRCS

15. Phosphorus Loading Why: Lake health indicator, erosion indicator
Data: land use, [phosphorus] field data
From: Water samples and Land Use/GIS group

16. Other Maps Soil types Permeability K-Factor Buffer Quality
Depth (ft) Ü
0.25
0.5
0.125
Miles
Soil types
Permeability
K-Factor
Buffer Quality
Water Quality Sampling Sites
Roads
Bathymetry*
Bathymetry of Pleasant Pond, ME

17. How to build a model
Modeling erosion potential in the Belgrade Lakes region
Input variables
Soil
Slope
Land use

18. How to build a model Convert vector land use data to raster Vector
Each land use type has an erosion potential rating of 0-9

19. How to build a model Convert vector soil data to raster Vector Raster
Reclassified K-factor
Reclassified K-factors on scale of 1-7
Reclassified K-factor = 11.6Kf +1

20. How to build a model Slope data already is a raster! Slope raster
Convert to percentages
Reclassified on scale of 1-9
But it still needs to be reclassified

21. How to build a model Multiply raster values by variable weight
Soil K-factor: 40%
Slope: 30%
Land use: 30%
Soil
Slope
Land use
For example, the soil raster values were all multiplied by 0.4, to reflect the 40% weighting in the model

22. How to build a model
Add up the weighted variables with the Raster Calculator in Spatial Analyst

23. Higher cell values indicate higher erosion potential
Voíla!
Higher cell values indicate higher erosion potential

24. Questions?