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Notes from HJ Andrews Small Watershed Group

Notes from HJ Andrews Small Watershed Group

Aug 15, 2000

 

posted on web - www.fsl.orst.edu/lter/pubs/hjalter/wag/aug2000.htm

 

email list - hjahydro@fsl.orst.edu

 

attendees at this discussion:

Fred Swanson, Stan Gregory, Gordon Grant, Dick Waring, Barbara Bond, Mark Harmon, Art McKee, Kate Lajtha, Linda Ashkenas, Julia Jones, Don Henshaw, Sherri Johnson

 

Brief summaries of present and ongoing research:

 

sap flow- Barbara Bond

The long-term goal is to better understand how vegetation age, structure, and species composition affects hydrological patterns in the H.J. Andrews.The primary objective has been to compare seasonal water use of a dominant angiosperm (red alder, Alnus rubra) and gymnosperm (Douglas-fir, Pseudotsuga menziesii) in the riparian zone of WS 1 and 2. We are also interested the role of transpiration by red alder and Douglas-fir relative to diurnal patterns of stream flow. A graduate student (Georgianne Moore) is starting to work on this project. In the perennially moist riparian zone, we expect that transpirational water use by Douglas-fir (per unit leaf area or per unit sapwood area) decreases in summer afternoons as vapor pressure deficit increases and stomata close, whereas transpiration by red alder remains more constant through the hot summer days.

 

flow paths and hydrologic modeling -Jeff McDonnell

Several projects with the general focus of better understanding hillslope hydrological processes and streamflow generation mechanisms across scales.Jan Seibert and I are using a lumped hydrologic model (HBV) to simulate effects of harvesting on large basins in and around the Andrews using the Jones/Grant data for large watersheds. The idea is to calibrate/validate the model using pre-treatment data and then continue the simulation after the cut. A new graduate student (Kevin McGuire) will be looking at water age distribution across scales and under low flow and event conditions. An exchange student from Germany will be here this winter and most likely assist with starting this project. A scientist who will be on sabbatical this winter at OSU (Rick Hooper, USGS) is thinking about using the historical biogeochemical data series from the Andrews to examine if simple EMMA work might be a good way to start to conceptualize streamflow generation processes at these sites.

 

flows - Julia Jones

Finishing analyses of effects of changes in vegetation and forest cover on low flow stream discharge at ten basin pairs in western Cascades: WS 1, 2, 3, 6, 7, 8, 10.Following upon David Post�s work, we are analyzing changes in streamflow after 100% canopy removal at several forested LTER sites (Oregon, New Hampshire, North Carolina). With former graduate student Reed Perkins, writing up study looking at synchroniztion of rain events among basins and comparing with rain-on-snow responses in lysimeters, small basins andlarge basins.

Manuscript just out in Water Resources Research. Its title is �Hydrologic processes and peak discharge response to forest removal, regrowth, and roads in ten small experimental basins, western Cascades, Oregon.�A proposal has been submitted to NSF to explore hydrologic regimes as the basis for a classification of small basin behavior at 25 sites including LTER, ILTER, WEBB, USDA.. Coauthors include McDonnell andPost.

 

nutrient dynamics, spiraling and temperature- Sherri Johnson

Research is examining stream nutrient spiraling distances in paired watersheds with differing forest harvest histories (WS 1, 2, 6, 8, Mack and McRae Clearcut vs Old growth). A graduate student (Alex Farrand) will be conducting these studies with collaboration and funding from EPA scientists.Also being examined are whole stream metabolism rates at each site.Stream temperature research is continuing across the HJA (manuscript just out in CJFAS 57, supplement 2, pages 30-39 - �stream temperature responses to forest harvest and debris flows in western Cascades, Oregon). Micrometerological factors at several sites are starting to be measured in order to construct heat budgets to better understand seasonal influences on stream temperature dynamics as a function of forest cover type and density.

 

sediment transport - Gordon Grant

Examining geomorphic responses to logging-induced flow changes. With Shannon Hayes, I am specifically trying to separate sediment dynamics due to increased sediment supply following forest harvest from changes in sediment transport without increased supply and only from changed in discharge. I am interested in scaling up several HJA studies to the regional scale especially to look at sediment production and effects of stream source on summer flow dynamics.

 

vegetation dynamics - Dick Waring

A project is beginning with Andy Hansen to examine biodiversity responses to structural and climatic diversity, including sites on HJA.Ecological hot spots for migratory birds and other biota have been hypothesized to be related to the length of time between bud burst and full leaf out during spring. These will be explored further in a GIS analysis coupled with field observations.Efforts are also being directed to modeling leaf area versus stem densities and photosynthetic activities on high gradient surfaces.

 

riparian wood loading - Stan Gregory

Exploring long-term processes that shape aquatic ecosystems, identifing critical links between forests and streams, and examining the influences of natural and anthropogenic disturbances on stream communities.We have continued the long-term study of riparian forests and wood in a 1-km reach of Mack Creek.�� We have analyzed the database and are preparing a manuscript to be submitted prior to the Wood Conference in October 2000.A graduate student (Mark Melanson) is almost finished developing a dynamic model of stand dynamics, wood input, decomposition, and redistribution.The model operates across scales of reaches to basins and over time frames of years to centuries. A new graduate student (Dan Sobota) will be expanding parameterization of the model.Results of research on riparian areas, wood dynamics and fish populations has served as a basis for development of fish and invertebrate models for Cascade Mountain and Willamette Valley Ecoregions.Models of historic conditions and future scenarios for wood delivery, riparian forest conditions are being used to generate potential changes to fish and invertebrate communities.

 

soil chemistry- Kate Lajtha

Research involves examining biogeochemistry- inorganic versus organics.N retention and fixation in soil solution chemistry is being studied to examine what forests contribute to soil chemistry and what is retained versus leaking out.Other questions include where do nutrient go after leaching from leaves and what forms SOM

 

debris flows- Fred Swanson

Continuing to examine driving processes for debris flows.What factors are natural drivers and controls of debris flows and which are intensified or reduced by forest management activities is of great interest.How factors of network and patchworks interact over time and space in multiple processes is also a focus of study.

 

rating curves and databases - Don Henshaw

Working on the intersite hydrology project and database (HydroDB) plus looking for help this fall on updating rating curves with and without V notches.

 

Other ongoing projects in small basins:

�������������� litter dynamics (historic) and tree cores- Valerie Frazier

�������������� plant geography- Briana Lindh��

�������������� long term veg transects - Howard Brunner and Steve Acker

�������������� litter decomposition- Bruce Caldwell

 

Recently completed research by students:

hyporheic study - Tamoa Kasahara. MS, Dept. of Forest Sciences, Oregon State University, Corvallis.

 

debris flow history - Kai Snyder, MS, Dept. of Forest Sciences, Oregon State University, Corvallis.

 

historic nutrient dynamics - Kristen Vanderbilt. Patterns of Nitrogen Fluxes in Watersheds of

the H.J. Andrews Experimental Forest, OR. Ph.D. dissertation, Dept. of Forest Sciences, Oregon State University, Corvallis.

 

stream channel change - John Faustini. Stream channel response to peak flows in a fifth-order mountain watershed.Ph.D. dissertation, Dept. of Geosciences, Oregon State University, Corvallis

 

hydrologic and nutrient modeling- Christina Teague

 

Other research submitted to peer review journals:

Hydrologic regimes - David Post and Julia Jones.Hydrologic regimes at four long-term ecological research sites in New Hampshire, North Carolina, Oregon, and Puerto Rico. Submitted to Advances in Water Resources.

 

hyporheic transport and retention - Steve Wondzell, submitted to WRR

 

Potential future activities and long range objectives:

- points listed but not discussed due to limited time - to be continued at next meeting - Sept 11, 2000

Modeling and integration of research activities - synthesis

�������������� ideas discussed for various ways synthesis activities could be encouraged including process modeling of watersheds, landscapes, and streams and issues of scaling.

 

Satellite sites - other small watershed study sites for potential comparisons of effects of forest management

�������������� could be important sites to scale up for NEON activities

�������������� Coyote Creek

�������������� Alsea Basin

�������������� Barometer watersheds, Umatilla National Forest

�������������� Wind River

 

Potential manipulations of small watersheds for study

�������������� road effects, road removal activities

�������������� forest thinning

�������������� fertilizer additions

 

Present data collection, measurements and potential future needs

�������������� ISCO samplers

�������������� nutrient, discharge, sediment sampling for answering specific questions

 

Hydro-NET - web data from other experimental forests

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