1. The utility of spatially explicit variables in watershed scale phosphorus water quality modeling
Mark Breunig
GEOG 681

2. What?

3. The utility of spatially explicit variables in watershed scale phosphorus water quality modeling

4. Why?
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).

5. WARNING: USLE & its derivatives used at the “field scale” =
USLE & its derivatives used at the “field scale” =
USLE & its derivatives used at the “watershed scale” =

6. 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 USGS
2001 NLCD (National Land Cover Database) - USGS
30 DEM – USGS
SSURGO – NRCS

7. The Data

8. R2 = 43% p < 0.001 2001 – 157 sites 2002 – 78 sites 2003 – 5 sites
Total: 240 sites

9. Σ(eFLag* β)
Σ(eFLall* β)
Pixel Value
(proportion – no units)

10. Problems
SSURGO !!!
30 m DEM!!!
Model Conceptualization

12. Further Work
CV Slope
Cumulative Slope
Ksat_r