1. USING HYDROLOGY TO COMPARE A REGIONAL HYDROGEOMORPHIC (HGM) CLASSIFICATION ACROSS A LATITUDINAL GRADIENT OF THE APPALACHIAN MOUNTAINS
Charles Andrew Cole - Penn State University
Chris Cirmo - SUNY, Cortland
Denise Wardrop - Penn State University
Robert P. Brooks - Penn State University
Jessica Peterson – Penn State University

2. Riparian Depressions NY PA VA

3. 1997 HGM key for the Ridge and Valley
A quick means of identifying HGM subclass
A direct way into the assessment of function
May or may not work anywhere else along the Appalachian Mountains
Objective: Use hydrology to assess HGM key north and south along Appalachian Mountains

4. Hydrogeomorphology Depression Slope Floodplain Fringing Flats
Impoundment

5. Reference Wetlands Group of natural wetlands w/in a region
‘Pristine’ to disturbed
Used to develop range of expected conditions
Problems include:
Lack of good data
Hard to get good data
Need landscape component
Relationship between functions and values?

6. Riparian Depression Adjacent to streams
Surface outlet with unidirectional flow
No water from overbank flooding
Soils saturated, rarely flooded
Low energy systems
PEM, PSS, PFO

7. Slope On topographic gradient Surface and groundwater
Saturated, rarely inundated
Low energy systems
PEM, PSS, PFO

8. Headwater floodplain Adjacent to 1st, 2nd order streams
Not much overbank flooding. Overland flow, groundwater
Saturation. Often dry
Low to high energy
Frequently PFO, PSS

9. Hydrology
RDS WL40’s and Ecotones

10. 1=PA 2=NY – AD 3=NY – Cat 4=VA Headwater floodplains Slopes
Riparian depressions

11. Median depth (cm) – headwater floodplainPA
NY-A
NY-C VA
(Kruskal Wallis H=5501.1, df=3, p<0.000)

12. Median depth (cm) – slopePA
NY-A
NY-C VA
(Kruskal Wallis H= , df = 3,P< 0.001)

13. Median depth (cm) – riparian depression
NY-A
NY-C VA
(Kruskal Wallis H= , df=3, p<0.001)

14. Headwater floodplain
Slope
Riparian depression

15. Wet and dry periods – by HGM subclass

16. And the reason is….

18. Credit: David Westphalen/Painet Inc.

19. New York wetlands were substantially impacted by beaver
Hard to find any site that was not modified by a beaver
Really altered the duration of wet periods (though not dry periods)
Reduced fluctuations

20. We will need to revamp the HGM classification
Works well south … other locations depend on beavers?