1. Flowpath or stream?: Reconciling the interaction of soil hydrology and stream function in the coastal temperate rainforest. David DAmore, USDA Forest Service Pacific Northwest Research Station Juneau, Alaska

2. Hydropedology is the linkage between soil science andhydrology that studies the multi-scale interaction between pedologic and hydrologic properties of theearths critical zone. 3. The functional response to structuralrestoration measures is uncertain andvaries through time. 4. The Alaskan coastal temperate rainforest(ACTR) is a sub-region of the perhumidzone of the coastal temperate rainforestbiome that extends from northern California to Prince William Sound.Map courtesy of inforain:www.Inforain.org 5. Stream: A body ofwater with a current,confined within a bed and stream banks. 6. The riparian zone definition for the coastal temperate rainforest is: The area outside of the activeriver channel that is influenced byor influences the adjacentterrestrial ecosystem 7. The study of soil hydrology is concerned with:1) The duration of saturation within a soil;2) The flow routing or how water moves through a system;3) The quality of water that is derived from a water source. 8. There are two key concepts for integrating hydrology and biogeochemistry in the ACTR:1) Hydropedology is the combination of soil science and hydrology that studies the relationships between soil,landscape, and hydrology.2) Flowpath integration is the study of how the flowpathof water and the material entrained in the flowpath integrates stream and landscape heterogeneity. 9. Landscape hierarchies can partition the watershed into functional units. 10. The catena provides a good model for hydrologic soil formation on hillslopes in the CTR. UplandsTypic Cryohumods Forested Wetlands Euic Terric CryosapristsUpper BackslopeBogs Dysic Typic CryohemistsLower BackslopeFootslopeToeslope 11. The Juneau hydrologic observatory has three hydropedomorphic systems replicated within three watersheds: sloping bogs, forested wetlands, and uplands. 12. Water Balance: Q=P-E-S 13. Water, water everywhere.The CTR receives an average of three meters of precipitation per year. 14. 0.2Type I 0.18PrecipitationDischarge Discharge varieswith watershed 0.16 0.14 0.120.1elevation, and slope 0.08 0.06 0.04 0.020jan febm ar apr m ayjunjulaugsepoctnovdecType II0.2 0.18 Precipitation 0.16Discharge 0.14 0.120.1 0.08 0.06 0.04 0.02 0jan feb m arapr m ay junjulaugsepoctnovdecType III0.2 0.18 Precipitation 0.16Discharge 0.14 0.120.1 0.08 0.06 0.04 0.02 0jan feb mar apr may junjul augsep octnovdec 15. Distribution of Watershed Types Type I in Southeast Alaska# 1525Area (km2)17,870 Type 1Mean elev (m) 142 Glacier BayNational Park Type 2Mean max (m)455 Type 3Annual Q (km3) 42 Area not included in analyses DOC flux (Tg) 0.29JUNEAUMean % wetland 9.0 Type IIC A USA NA#1213DA Area (km2) 28,456Mean elev (m) 381Mean max (m)978Sitka Annual Q (km3)95 PetersburgDOC flux (Tg)0.40 Mean % wetland11.8Pa Type IIIcific# 110 Oc Area (km2) 19,962 eanMean elev (m) 857KetchikanMean max (m) 1846 Annual Q (km3)70DOC flux (Tg)0.100 50100 Mean % wetland 4.2 Kilometers 16. The coastal temperate rainforest is nearlyalways in a state of moisture excess. 200200 Precipitation Evapotranspiration 150150 P-PET 100100Ppt, ET (mm) P-PET (mm)5050 00-50 -50 -100 -100 ary ary rch April y Ma Jun eytr rr Jul ugus embe ctobe embe emberJ anu Febru Ma A eptO NovcSDe 17. Seasonal water table patterns vary acrossthe hydropedomorphic gradient.10UplandForested WetlandSloping Bog 0 Water Table Depth (cm)-10-20-30-40-50May Jun Jul Aug Sep OctNov 18. The production and export of dissolved organic carbon is influenced by soil biogeochemical cycles. 30 Sloping Bog Forested Wetland 25Upland 20DOC (mg C L-1) 15 10 5 0 MayJun Jul Aug Sep Oct Nov 19. The forested wetlands and bogs have distinct seasonal patterns in water table depth. 0 -5 Water Tables Water Table Depth (cm)-10-15-20-25-30Forested WetlandBog-35-40 ay lyne t r ers be Jugu obM JuemAu ct OptSe 20. Soil saturation influences the biochemical transformations in the soil profile. -0.10 700 -0.15 Aerobic 600Water table depth (cm) -0.20 Redox potential (eH) 500 -0.25 -0.30 400 -0.35 Anaerobic 300 -0.40 Water Table Depth Redox Potential -0.45 200 Jun Jul Aug Sep Oct Nov Dec 21. All dissolved organic matter is not created equal.Fluorescence ExcitationEmission Matrices (EEMs)PARAFAC6005055040Relative % Contribution50030Emission (nm)450204001035001 2 3 45 6 7 8Components300240 260 280 300 320 340 360 380 400 420 440Excitation (nm)Protein-like fluorescence(Tyrosine and Tryptophan-like) 22. Biodegradable DOC is related to protein,which varies according to soil type.50A40BDOC (% C loss) B B30C20 6010 50 BDOC (% of initial DOC)040BogFW FenUp 306.27.27.3 2.7 mg C L-1 20 100010 203040 Fellman et al., Biogeochemistry, 2008Protein-like fluorescence(% relative contribution) 23. InletOutletReduced terrestrial organic matter is oxidized duringprocessing in aquatic systems. Miller et al., 2009, Fellman et al., 2009 24. Soil types can be arrayed by functional attributesfor evaluation of performance standards.1.21.0Fen Fen Protein-like fluorescence0.8Fen0.60.4 Axis 2 Bog0.2 Bog0.0UplandBogUpland-0.2-0.4FW-0.6 FW FW-0.8-0.4 -0.3 -0.2-0.10.00.10.20.3 Axis 1Humic-like fluorescence 25. Southeast Alaska has thehighest area weighted flux of dissolved organic carbon inthe world.1412TongassMg C km-2 y-110AmazonYukon 8 6 4 Persistent fluxes of water 2through soils provide a 0terrestrial carbon pump tostreams. 26. The terrestrial and aquatic ecosystems areintimately connected due to extensive shorelines.Dissolved Organic Carbon Flux fromSoutheast Alaska Rivers Surface Chlorophyll Concentrations Total DOC Flux, Tg/Year Glacier Bay 0.000004 - 0.000353National Park during summer 0.000354 - 0.001013 0.001014 - 0.002728 0.002729 - 0.008332 JUNEAUArea not included in analyses ! CA SA NA U DA !SitkaPetersburg!Pa cific Oc ea n ! Ketchikan0 50 100 Kilometers 27. The North Pacific coastal fringe is a focal point forchanges in key environmental drivers such as temperature and precipitation.http://www.assessment.ucar.edu/modeling_scaling/img/future.gif 28. Predictions for temperature change showincreases for southeast Alaska, while predictions for precipitation change show increases, but the uncertainty in estimates for SE Alaska are high. 29. Evapotranspiration may expand the aerobic zoneof soils during times of soil moisture deficit. 0 Water Table Depth (cm)-10-20-30Sloping BogForested WetlandForested wetland 2050-40May Jun Jul Aug Sep Oct Nov 30. The catotelm, or aerobic zone in surface soilswill increase during soil moisture deficit. 0 Water Table Depth (cm)-10-20-30Forested wetlandSloping bogForested wetland 2050-406/5/2006 6/12/20066/19/2006 6/26/2006 31. The water table relationships can beextraploated to thewatershed through soildrainage classcategories. 32. Drainage classes can be scaled tofiner landscape units using digitalelevation models. 33. Flowpath models can be applied using water tabledepths to arrayclasses in accurate categories. 34. Hydropedologic studies can provide watershed models for: flowrouting, duration of saturation, quantitative hydrologic evaluations and biogeochemical characterization. 35. Landscape wetland distributions can beused for planning functions at broad scales.