Date post: | 21-Dec-2015 |
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Developing GIS indicators and metricsDeveloping GIS indicators and metrics
David TheobaldNatural Resource Ecology Lab
Colorado State University
Goals of indicator developmentGoals of indicator development
Develop and evaluate landscape-level indicators suitable for spatial and temporal analyses of EMAP data
Investigate limitations of currently-available data and offer new, robust methodologies
Current effortCurrent effort
1. Linkage between watershed and hydrologic networks
2. Refine surrogates with direct measures of area and discharge
3. GIS-based toolsa. RWTools for ArcViewb. Catchment delineation & discharge in
ArcGIS
1. Watershed–hydrological 1. Watershed–hydrological network linkagenetwork linkage“…in every respect, the valley rules
the stream.” – Hynes 1975Indirect measures based on
hydrological properties (e.g., Strahler order, drainage density, etc.)
Distance:Distance:
As the crow flies As the seed floats As the fish swims
(down & up stream) Upstream length
- mainstem (2)- arbolate (1+2+3+4)
Distance:Distance:
As the crow flies As the seed floats As the fish swims Upstream length Network (dams,
fragmentation)
What indicators measure What indicators measure watershed-stream linkage?watershed-stream linkage?Length of stream line– Dam alteration of flow at a downstream
gauge?
RWTools extension (ArcView v3.2)
2. Direct measures of discharge 2. Direct measures of discharge
Surrogates developed, e.g. Strahler order: The usefulness of stream order assumes, with a sufficiently large sample, that order is proportional to stream discharge – Strahler 1957
Alternatives:- basin area- discharge
Delineate reach catchmentsDelineate reach catchments
Robust method (no pre-processing)1 to 1 relationship NHD reach and
catchment“Grow” watershed from reach line
based on flow direction iteratively
Stream dischargeStream discharge
Encouraging preliminary resultsAdditional factors (Infiltration, E.T.): – Geology– Land cover– Exposure
D = f(C, G, L, E)
3. GIS-based tools3. GIS-based tools
Interactive query and analysis of watersheds (RWTools) (ArcView v3.2)
ArcGIS Geometric network
Plans for next yearPlans for next year
Initial release of GIS tools:– RWTools for ArcGIS– Functional-based spatial weights
Functional weighting Functional weighting
1
1 2 3
54
0 0 0 0 0 0 0
0.7 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0.7 0 0 0
0.2 0.8 0 0.2 0.8 0 0
0.1 0.2 1.0 0.1 0.2 1.0 0
W =
6 7
E.g., downstream hydrology
Functional weighting Functional weighting
1
1 2 3
54
0 1 0 0 0 0 0
1 0 0 0 1 1 0
0 0 0 0 0 0 0
0 0 0 0 1 0 0
0 1 0 1 0 1 0
0 1 0 0 1 0 1
0 0 0 0 0 1 0
W =
6 7
E.g., macroinvertebrates