1. Debra S. Baker and Donald G. Huggins
Nutrient Trends in Reference Streams of the Central Plains
Debra S. Baker and Donald G. Huggins
Central Plains Center for BioAssessment
Kansas Biological Survey, University of Kansas
30th Annual Great Plains Limnology Conference, Lincoln, NE, 10 – 11 October 2003

2. Nutrients in Streams
Clean Water Action Plan USEPA initiative to establish regionally-based nutrient criteria for waterbodies via Regional Technical Assistance Groups (RTAGs).
Develop a dataset of nutrient levels found in “reference” or least impacted streams of USEPA Region 7.
Should criteria be single values for the entire EPA Region, or should criteria be based on a subset of stream characteristics, such as ecoregion?

3. Stream Sites

4. Parameters in situ: DO, turbidity, pH, conductivity Lab analysis:
TN, NH4-N, NO3-N,
TP, PO4-P,
chlorophyll a, phaeophytin a

5. Hypothesis
Streams will show affiliations based on some suite of water quality characteristics (e.g. nutrient concentrations).
Principal Components Analysis (PCA) was used to determine probable relationships among the parameters.
Resulting factor scores were used as input for clustering analyses to identify stream groupings and compare resulting spatial differences to ecoregions.
Analyses

6. Resulting Dataset May 1999 – June 2002
94 streams, 522 records, taken at base flow
TN: 5 – g/l; Median: 1180 g/l
TP: 2.5 – 1320 g/l; Median: 86 g/l
Chlorophyll a: 0.5 – 216 g/l; Median: 4 g/l

7. PCA Analysis Factor 1 TP, PO4-P Factor 2 TN, NO3-N
Factor 3 chlorophyll a, phaeophytin a
Factor 4 pH, DO
Factor 5 conductivity
Factor 6 NH4-N

8. K-means Cluster Analysis
Calculated medians of the 6 PCA factor scores for each of the 94 sites.
K-means cluster analysis on all PCA factors – resulted in 6 clusters.
K-means cluster analysis on just the nutrient factors – resulted in 6 clusters.

9. Clustering on All Factors

10. Clustering on Nutrient Factors

11. N & P Factors

12. N & P Factors

13. N & P Factors

14. N & P Factors

15. N & P Factors

16. N & P Factors

17. N & P Factors

19. The 94 reference streams vs
The 94 reference streams vs. a database of nonreference streams (# records ~ 24000; # streams ~ 1500)

20. Conclusions Nutrient levels varied by ecoregion.
Streams that we clustered by nutrient factors and independently of ecoregion showed ecoregional affiliations.

21. Future Study Seasonal influences Chlorophyll a
USEPA Region7 Nutrient RTAG
Macroinvertebrates
Watershed and land use