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The utility of spatially explicit variables in watershed scale phosphorus water quality modeling. Mark Breunig GEOG 681. What?. The utility of spatially explicit variables in watershed scale phosphorus water quality modeling. Why?. - PowerPoint PPT Presentation
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The utility of spatially explicit variables in watershed scale phosphorus water quality modeling
Mark BreunigGEOG 681
What?
The utility of spatially explicit variables in watershed scale phosphorus water quality modeling
Although efforts are underway to set stream standards in Wisconsin and elsewhere, there is still controversy regarding the mechanisms that control stream phosphorous concentrations. This represents a collective misunderstanding of the fundamental processes that control water quality at the catchment scale (Boomer et al. 2008). It is a very common practice for researchers to attribute poor results to inadequate spatial data (Hunsaker et al. 1995; Soranno et al. 1996; Jain et al. 2000; Jones et al. 2001; Richards et al. 2006; Boomer et al. 2008).
Why?
WARNING:USLE & its derivatives used at the “field scale” =
USLE & its derivatives used at the “watershed scale” =
Purpose of Model: to increase the effectiveness of watershed-scale phosphorus water quality modeling
Taxonomy of Model: Deterministic, empirical, inductive
Data Inputs: Field Data collected by USGS2001 NLCD (National Land Cover Database) - USGS30 DEM – USGSSSURGO – NRCS
The Data
0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00
-2.50
-2.00
-1.50
-1.00
-0.50
0.00
0.50
% Ag vs Log(TPmedF)
% Agriculture
Log
(TPm
edF)
2001 – 157 sites2002 – 78 sites2003 – 5 sitesTotal: 240 sites
R2 = 43%p < 0.001
Σ(eFLag* β)
Σ(eFLall* β)
Pixel Value(proportion – no units)
0
10
20
30
40
50
60
70
80
90
100
0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000
Pixe
l Val
ue (%
effe
ctive
)
Distance (m)
0.05000
0.01000
0.00250
0.00100
0.00043
0.00022
0.00011
0.00006
0.00003
0.00001
0.00000
0.0%10.0%
20.0%30.0%
40.0%50.0%
60.0%70.0%
80.0%90.0%
100.0%
-2.5
-2
-1.5
-1
-0.5
0
0.5
f(x) = 0.83620511211752 x − 1.44411517151365R² = 0.455085267094821
Pixel Value vs logTPmedF
ProblemsSSURGO !!!30 m DEM!!!Model Conceptualization
Further WorkCV SlopeCumulative SlopeKsat_r