A Stream Shade Model for ArcGIS

Dave Stockdale USFS Region 6 Data Resources Management

ESRI Federal GIS User Conference February 2013

Introduction

n Originally developed under Inter-Agency Agreement n US Forest Service n Oregon Dept. of Environmental Quality n Bureau of Land Management

n Used to automate Water Quality Restoration Plans (WQRP)

History n ArcInfo Workstation – AML n ArcGIS 9 – VBA and Python n ArcGIS 10 - Python n Based On Shadow 1980’s -1993

n A program to predict temperature increases from management activity

n Original developers John Hawkins, formerly of Rogue River-Siskiyou National Forest, and Chris Park, Forest Hydrologist, Rogue River-Siskiyou N.F.

Model Components

n Stream Orientation n Stream Width n Buffer providing shade n Tree height n Slope n Canopy closure

Photo by Cynthia Buckert, Black Hills NF

ArcInfo vs ArcGIS n Old model was comprised of a

series of AML programs that calculated the various stream shade components.

n New model runs with two script tools developed in Python: § Rapid_10 creates the datasets

necessary to perform the shade calculations, and runs the shade analysis.

§ Shade Model Map creates a basic map of the project area, shade values and others.

n Model will run on Enterprise File System (T drive) or on user’s C drive.

Model vegetation databases

n The model uses vegetation databases developed by the Landscape Ecology, Modeling, Mapping and Analysis (LEMMA) group at the USFS Pacific Northwest Research Station and Oregon State University, using the Gradient Nearest Neighbor (GNN) imputation method.

Photo by Beverly deGruyter, Cibola NF

Model vegetation databases

n Northwest Forest Plan area – 2006 imagery

n Remainder of region – 2000 imagery

n Original version used vegetation data from the Interagency Vegetation Mapping Project (IVMP) that covers only the Northwest Forest Plan forests in Oregon and Washington.

Stream Orientation n Originally based on the ArcInfo

FlowDirection Grid command n Values 2,8,32,128 Stream orientation

is 45 degrees n Values 1 or 16 stream orientation is

90 degrees n Values 4 or 64 stream orientation is

0 degrees

n Now the Spatial Analyst Flow Direction tool in Hydrology toolbox

32 64 128

16 1

8 4 2 Photo by Lonnie Murphy, Ochoco NF

Stream Width

n Based on accumulation of area and the Regression analysis of Bankfull widths vs. Area

n Width = 12.19 * Area0.39

Bankfull Width vs Drainage Area (Baker, Salmon )

6.5

12.0

37.0

8.07.0

20.0

35.0

45.00

6.0

35.00

32.0

28.0

48.0

9.0

31.0

16.0

4.5

29.0

36.00

y = 12.19x0.39

R2 = 0.96

0

10

20

30

40

50

-1 4 9 14 19 24Drainage Area (sq. mi.)

Ban

kful

l Wid

th (f

t.)

Buffer Providing Shade

n 150 feet from stream n This better represents

the vegetation height, and averages out errors associated with satellite imagery

n Side slope with an azimuth between 270 – 90 Degrees provides shade to the stream

Photo by Tom Moris, Chiquamigon-Nicolet NF

Tree Height

n Tree height in previous

model used an estimated height calculated from dbh

n In the current version stand height is a field in the vegetation attribute table, so there is no need to estimate heights.

Photo by Brian Barr, Tongass NF

Slope

n Slope is calculated as percent slope

Photo by Amy Unthank, Prescott NF

Calculate each Stream Cell Value for Shadow

n Calculate Averages for the Stream Cell

n 5 Inputs Needed for Shadow n Tree Height n Stream Width n Stream Orientation n Side Slope n Canopy Closure

effective shade buffer

57

18

0

10

5

Shade

n Regression derived from data entered into Shadow model. n -23.1 - (.1327 * (ln(tree_avg) *

ln(stm_width))) + (10.37 * pow(stm_width, -.1559)) + (11.38 * pow(tree_avg, .1116)) - (.5434 * cos(stm_orent.rads)) + (.2487 * slope_avg) + (.4204 * (cos(stm_orent.rads) * ln(stm_width))) Photo by Jim Kilgore, Klamath NF

Existing vs. Potential Shade

n This allows you to start playing what if games with thinning and planting.

n Identifies what areas may respond to management.

n Based on simple ArcMap queries

Photo by Mary Lou Welby, Malheur NF

Running the Model

n The Reference Layers category contains the parameters representing the base layers needed to run the model.

n A default value is provided for each one on the T drive.

Running the Model

Running the Model

Running the Model

Running the Model

Running the Model

Outputs n pab – project area boundary, the watershed being analyzed n sixthfield – sixth field subwatersheds within the project watershed n stm_line – all the streams with no attributes n shade_line – contains the shade information n sixth_summary – table containing average existing shade and average expected target shade values for

each subwatershed n n If the watershed is within the Northwest Forest Plan area, determined programmatically, 2 additional

outputs are copied: n lua – land use allocations according to the NWFP n critical_line – shows critical reaches (stream segments in actively managed areas within the shade zone) n n 27 or 29 raster datasets, depending on whether or not the watershed is in the NWFP area. The rasters

which are used in the map are these: n qmd_pab – vegetation raster (stand height and canopy cover) n aspect – aspect and shade zone (north and west aspects) n hillshade n mgt_areas – raster showing managed and non-managed areas and those in other ownership (if in a

NWFP area)

Running the Model – C drive

n Copy source datasets referenced in the program to the C drive: § Clip from regional DEM § Clip from regional vegetation dataset § Regional watershed and subwatershed datasets § Land Use Allocation dataset, for the NWFP area

n Copy toolbox and scripts to the C drive

Running the Model – C drive n Reference Layers folder n T:\FS\Reference\GeoTool\r06\Application\StreamAssessment\ReferenceLayer

s

Running the model – C drive

n Change default values of reference layers from T to C drive locations

Map Creation

n Use the Shade Model Map tool

Map Creation n Map template –

T:\FS\Reference\GeoTool\r06\Application\StreamAssessment\Rapid_template.mxd

Map Creation

n 4 map types

n Layer files symbolize the map layers

Map Creation

Map Creation

Active Restoration Opportunities

n Planting n Canopy cover 0-50% n Stream width < 100 ft n Existing shade < 80%

n Thinning n Canopy cover > 70% n Stream width < 150 ft n Existing shade < 80%

Planting/Thinning Opportunities

Limitations - Considerations

n Vegetation database is intended for use at larger scope. It is suitable at the 5th field watershed and above, not site-specific project work.

n Stream Network is defined by the DEM’s n Possible improvement – use other

attributes from vegetation database to further refine the model

Acknowledgements

n John Hawkins – original developer n Chris Park – hydrologist, Rogue River-Siskiyou

National Forest n Mike Rich – geospatial tools developer, USFS

Region 6 Data Resources Management n Peter Eldred –natural resources specialist, USFS

Region 6 Resource Planning and Monitoring

Questions?