1
HydroDBmetadatadraft4.doc
7/23/01
DRAFT METADATA STANDARDS FOR SMALL, EXPERIMENTAL
WATERSHEDS
IN THE HYDRODB (STREAMFLOW DATA BASE) WEB SERVER PROJECT
Drafted by Fred Swanson, Doug Ryan, Don Henshaw, Julia Jones
What is HydroDB and Why Does it Require Metadata?
HydroDB is a centralized server to provide open access to long-term stream flow and
accompanying meteorological records from a large collection of research watersheds via
the world-wide web. We expect that easy access via the web will permit these long-term
data to be extensively used for a wide variety of research, field application, educational,
and other purposes. However to make these long-term records most useful, they need to
be accompanied by carefully prepared metadata that consist of explicit background
descriptions of how these environmental measurements were made and what conditions
existed in the watershed that may have influenced what was observed. We propose the
following standard metadata formats and content to provide the basic information that
will be needed to make valid interpretations of long-term records in HydroDB by
anticipated and emerging users in the future. These standards represent a compromise
between the resolution that is desirable for detailed analyses and comparisons within and
among the many watersheds in HydroDB and the wish to keep the burden of gathering
and recording metadata at a reasonable level. Our plan is to start quite modestly in terms
of types and temporal resolution of data (daily flow), but to build a base for future
sharing of data of other types and resolution (e.g., precipitation and stream water
chemistry).
What precedents exist for the HydroDB Metadata Standards?
National metadata standards for ecological data are emerging. See the FGDC Biological
Profile http://www.nbii.gov/datainfo/metadata/standards/index.html and the similar
Ecological Metadata Language http://knb.ecoinformatics.org/software/eml/eml-1.4.html.
Sites are encouraged to develop data conforming to one of these standards for all study
data. The proposed more specific metadata elements for HydroDB are based on formats
developed by Julia Jones and David Post for use in the Long-Term Ecological Research
(LTER) Intersite Hydrology Project (see:
http://www.fsl.orst.edu/~post/hydro/index.html) and from standards developed in the
ClimDB project for climate data
http://www.lternet.edu/community/committees/climate/climstan/climfmt.html.
How will metadata be provided to HydroDB?
The listed metadata elements will be prepared by each of the individual sites. Elements
are divided into those representing 1) the overall research study area, such as, principal
investigator, data set contact person, etc., 2) watershed metadata elements describing
2
watershed hydrologic characteristics, 3) gauging station location, weir description,
methods, etc., and 4) meteorological station (precipitation gauge and temperature)
location, description, methods, etc. Sites will be responsible to enter/cut-and-paste their
metadata into Web forms that will be established at the central database site. Web
addresses linking more specific study information online at the individual sites may be
included as metadata elements.
Research Site Metadata:
1.
2.
3.
4.
5.
6.
7.
Research site name:
Principal Investigator/Database contact person/Other researchers:
Address (for each investigator or contact person):
Phone (for each investigator or contact person):
Email: (for each investigator or contact person):
URL for site webpage:
URL for the research site’s webpage location covering relevant watershed studies:
(webpage should include study abstract, watersheds in study, study dates
(begin/end), funding sources that supported data collection, experimental design,
quality assurance/quality control procedures (cite publications where possible),
data accuracy, data collection/instrumentation/analysis methods, calibration/rating
curve description and history, web links to other related hydrologic studies at the
site, web links to relevant supporting materials, publications).
8. URL of research site’s webpage location showing a topographic map of the
research site and the associated gauged watersheds (1:24,000 scale) with the
location clearly marked of each measuring weir, precipitation gage, and
approximate watershed boundaries. Alternatively, such a map can be pasted into
the metadata. [USGS topographic maps can be down loaded from the web for all
states (except Alaska & Puerto Rico) at:
http://navigator2.maptech.com/homepage/index.cfm]
Watershed Metadata (for each gauged watershed or weir) [Note: In cases of spatially
hierarchic (i.e., nested) watershed structures, if the information for a subset watershed is
the same as information listed for the parent watershed, then those metadata elements do
not need to be repeated and can be left blank.]
1. Watershed name (show on map, item 8 in Research Site Metadata) [common name –
add note of explanation if watershed is part of a nested set of watersheds or other
complication]:
2. Watershed code name (abbreviated code for watershed typically used in data sets):
3. Parent watershed code name (show parent watershed code name if watershed falls
within the boundary of a larger, gauged watershed that is part of the study area):
4. Hydrologic regime (e.g., perennial/ephemeral; rain/rain-on-snow/snowmelt):
5. Watershed bounding coordinates (latitude/longitude in decimal degrees (5 decimal
places) of rectangle bounding the watershed):
6. Watershed area (ha):
7. Aspect (o) (general exposure of watershed; direction of stream channel):
8. Watershed minimum and maximum elevation (m):
3
9. Weir/Gauging Station name (if different from watershed) (show on map, item 8 of
Research Site Metadata):
10. Weir/Station location (latitude/longitude in decimal degrees – 5 decimal places):
11. Weir elevation (m):
12. Begin date:
13. End date:
14. Log interval (data logger sampling interval (e.g., 15 second, 1 minute)):
15. Summary interval - finest time step output for streamflow data (i.e., 15 minute,
hourly, daily):
16. Weir type and instrumentation description:
17. Weir calibration and modification history (dates of major modifications or
recalibrations – if documented in site records, give directions to that information):
18. Methods (field collection, data aggregation, and quality assurance methods):
19. Data accuracy (specify units):
20. Identify precipitation gauging and ambient air temperature measurement
location/name that best represents conditions in the watershed monitored by this weir:
21. URL of weir photograph:
22. Channel length (m) [note: This is channel length of the entire stream network in the
study watershed. Specify perennial and/or intermittent and define criteria for
differentiating. Specify how the channel head, hence length, is defined using one or
more methods, e.g., a) field observations of threshold channel cross-sectional area; b)
critical drainage area of channel head modeled with cumulative drainage area
function in GIS analysis of DEM; c) contour crenulation criteria (specify criteria and
map scale); d) blue lines on map (specify map scale).]:
23. Drainage density (km/km2):
24. [note: Divide channel length (#7, above) by drainage area.]
25. Mean watershed slope (%) [note: this is basin-wide, average hillslope gradient.
Specify methods, e.g., sampling of DEM or topographic map.]:
26. Average annual precipitation (mm):
27. Pre-treatment vegetation (species) and cover types:
28. Pre-treatment stocking density (stems/ha), basal area (m2/ha), or LAI of dominant
species (give geographic pattern, if relevant (e.g., riparian vs. upland)):
29. Soil type (to family level of USDA soil classification system), depth (m), and
porosity:
30. Geology (including surficial geology):
31. Mean annual radiation received (joules cm-2 day-1):
32. Mean snowpack depth (m or mm water equivalent) or percent of precipitation falling
as snow:
33. History of treatments and natural disturbances in control/treated watersheds, both preand post-experimental manipulations (including fire history):
34. Hydrologically-relevant information on vegetation change (e.g., succession):
35. Relationship with control watershed (e.g., similarities, dissimilarities, physical
distance between control and experimental weirs and met stations, any disturbance
that occurred in “control” watershed:
36. Publications/References:
4
Meteorological Station Metadata (for each precipitation gauge & temperature
instrument)
1. Precipitation gauge name (show on map, item 8 of Research Site Metadata):
2. Precipitation gauge location (latitude/longitude in decimal degrees – 5 decimal
places):
3. Precipitation gauge elevation (m):
4. Begin date:
5. End date:
6. Log interval (data logger sampling interval (e.g., 15 second, 1 minute)):
7. Summary interval - finest time step output for data (i.e., 15 minute, hourly, daily):
8. Precipitation gauge type and instrumentation description:
9. Precipitation gauge calibration and modification history (dates of modifications or
recalibrations):
10. Ambient air temperature instrument type, name, location, history, and elevation
(m) (if different from precipitation):
11. Snow measurement type, method, name, location, history and elevation (m) (if
different from precipitation):
12. Methods: Field collection, data aggregation, and quality assurance methods:
13. Data accuracy (e.g., +-0.1oC temperature, +-10 mm precipitation):
14. URL of precipitation gauge photograph:
How will hydrology and climate data be provided to HydroDB?
Data will be prepared in a standard exchange format that will be a comma-delimited text
file with header lines showing included data elements, and made available at a web
address. Each site will provide the HydroDb administrator with this URL address for
their data. A list of the proposed data elements is shown below. Data can be prepared as
either a static text file, or dynamically produced using a web script. A central web server
will harvest each site periodically. The HydroDB administrator will contact each site
when problems occur. The HydroDB project will use the identical harvest engine
developed by LTER Information Managers in the ClimDB project (Henshaw et al.1998),
and further enhancements are underway. The ClimDB web page is here:
http://www.fsl.orst.edu/climdb/index.htm.
HydroDB will be developing its own front-end web page. Instructions for preparing
ClimDB data are listed in the following document and are similar to HydroDB:
http://www.fsl.orst.edu/hydrodb/documents/climhydro_userguide.html. Specific
HydroDB preparation instructions will be developed.
In this early prototype phase of HydroDB, sites are asked to prepare the following data in
the standard exchange format:
1.
2.
3.
4.
Daily average discharge (L/sec)
Daily precipitation (mm)
Ambient air temperature – daily maximum/minimum (oC).
Snow water storage (daily presence/absence or mm of water).
5
In later phases of HydroDB, the following data will likely be added (the means of data
access will be determined at a future date):
1. Discharge (L/sec) at finer temporal resolutions, i.e., 15 min
2. Precipitation (mm) at finer temporal resolutions, i.e., 15 min
What Data Analysis Tools are planned for HydroDB?
A variety of software tools is available for hydrology data. Initially, a monthly
aggregation tool operating on the mean daily values will be implemented, as well as a
graphical interface for displaying daily or monthly data. Convenient unit-conversion
tools (such as conversion of L/sec to cfs etc.) will be added to facilitate use by a variety
of users. Potentially, other tools can be implemented on the HydroDB web site in the
future, for example, a tool for converting files of continuous or other high temporal
resolution streamflow records to coarser time steps (e.g., daily). The NSF-funded LTER
Intersite Hydrology project, led by Julia Jones (Oregon State University) and David Post
(OSU and CSIRO, Australia) has developed tools to compare treated/control watershed
differences for use in published analytical approaches (e.g., Jones and Grant 1996, Jones
2000), and other analysis tools separating quickflow from baseflow, and making seasonal
and annual comparisons of control basins (Post and Jones, in press; Jones and Post, in
prep). Other tools to facilitate utilitarian and educational uses of these data (e.g. culvert
design for fish passage) may also be added as they become available.
Literature Cited
Henshaw, Donald L.; Stubbs, Maryan; Benson, Barbara J. [and others]. 1998. Climate
database project: a strategy for improving information access across research sites. In:
Michener,
William K.; Porter, John H.; Stafford, Susan G., eds. Data and information management
in the
ecological sciences: a resource guide; 1997 August 8-9; Albuquerque, NM. Albuquerque,
NM:
LTER Network Office, University of Mexico: 123-127.
Jones, J. A. 2000. Hydrologic processes and peak discharge response to forest removal,
regrowth, and roads in 10 small experimental basins, western Cascades, Oregon. Water
Resources
Research. 36(9): 2621-2642.
Jones, J. A.; Grant, G. E. 1996. Peak flow responses to clear-cutting and roads in small
and large basins, western Cascades, Oregon. Water Resources Research. 32(4): 959-974.
Jones, J. A.; Post, D. A. [In prep.]. Long-term streamflow responses to forest canopy
removal in Oregon, New Hampshire, and North Carolina. Water Resources Research.
Post, D. A.; Jones, J. A. [In press]. Hydrologic regimes at four long-term ecological
6
research sites in New Hampshire, North Carolina, Oregon, and Puerto Rico. Advances in
Water
Resources.