BADM Group: WTD

BADM Type: Soil
Description: Water Table Depth
Group Entries per Site: Multiple
Last updated: Mar 02, 2021

BADM Group Overview

BADM variables in this group are organized as shown below. The overview highlights what variables are required per group. It also indicates which variables cannot be specified together ( OR ) in the same group entry. See BADM Basics for more details.

Multiple entries of this BADM group can be reported per site. However, combinations of variables must be unique. Read more:

Required Variable
Optional Variable
Combinations
Examples
RequiredOptional
Water Table Depth
  • WTD
  • WTD_STATISTIC
  • WTD_DATE
  • WTD_STATISTIC_METHOD
  • WTD_STATISTIC_NUMBER
  • WTD_APPROACH
  • WTD_DATE_UNC
  • WTD_COMMENT
  • BADM variables: Definitions, Units, Requirements

    See Overview tab or BADM Basics for explanation of Required and Optional variables.

    Multiple entries of this BADM group can be reported per site. However, combinations of variables must be unique. Read more:

    Required Variable
    Optional Variable
    Combinations
    Examples
    Variable
    Requirements
    Units Description
    WTD
    Required
    mWater table depth (not continuous measurements)
    Report continuous half-hourly or hourly measurements with flux/met data.
    WTD_APPROACH
    Optional
    free textWater table depth measurement approach
    WTD_COMMENT
    Optional
    free textWater table depth comments
    WTD_DATE
    Required
    YYYYMMDDHHMMWater table depth measurement date
    Please report the date at the precision known. Allowed reporting precisions are YYYY, YYYYMM, YYYYMMDD, and YYYYMMDDHHMM.
    WTD_DATE_UNC
    Optional
    daysUncertainty in the Water table depth measurement date
    WTD_STATISTIC
    Required
    LIST(STATISTIC) ShowWater table depth statistic
    The statistic for the measurement reported. Use predefined list (e.g., mean, min / max, standard deviation, etc).
    STATISTIC Options×
    OptionDescription
    10th PercentileQuantile at 10% of distribution
    1st PercentileQuantile at 1% of distribution
    25th PercentileQuantile at 25% of distribution
    5th PercentileQuantile at 5% of distribution
    75th PercentileQuantile at 75% of distribution
    90th PercentileQuantile at 90% of distribution
    95th PercentileQuantile at 95% of distribution
    99th PercentileQuantile at 99% of distribution
    MaximumMaximum value
    MeanAverage (mean) value of sample population
    Measurement UncertaintyReport uncertainty as a plus or minus value in the measurement units. For example, enter 1.5 for +/- 1.5 units. Uncertainty may be reported from the instrument's specifications, determined empirically, or estimated by the tower team. Please describe such details in Approach. For uncertainty values that are better described by a range, a percent, or other, please enter information in Comments.
    Median - 50th PercentileMedian - Quantile at 50% of distribution
    MinimumMinimum value
    Single observationSingle observation that is not a calculated statistic of replicates either to get a robust estimate or for spatial variability analysis. For example a single biomass observation may be the vegetation harvested in a single 1 x 1 meter area.
    Standard DeviationStandard deviation may be reported from a sample population that consists of individual or aggregated samples (observations). If the distinction is important, specify in STATISTIC_METHOD or Comments.
    WTD_STATISTIC_METHOD
    Optional
    LIST(STATISTIC_METHOD) ShowWater table depth statistic method
    Method used to generate the reported statistic (e.g., aggregate of individuals, aggregate of sample aggregates) from observations representing the same time period. Use predefined list. The aggregation method is not meant to describe temporal aggregations for example in calculations of higher frequency observations (e.g., sub-minute) to lower frequency observations (e.g., hourly) at a single location.
    STATISTIC_METHOD Options×
    OptionDescription
    Aggregate of individual observationsThe statistic is aggregated from individual observations located within the site. Observations may be grouped into sample areas (e.g., plots) within the site but those groupings are ignored. Statistics generated from individual observations directly yield information on the site generally. The statistic may represent spatial characteristics of the measurement within the site (e.g., spatial heterogeneity) and/or characteristics due to other factors (e.g., population variability).
    Aggregate of sample aggregatesThe statistic is aggregated from aggregated individual observations located in sample areas within the site. For example, individual observations are made in 5 sample plots within a site. "Aggregate of sample aggregates" is used if a plot statistic (e.g., Mean) is first calculated, and then the plot values are aggregated to calculate the site statistic. Statistics generated by this approach are often used to highlight the spatial characteristics within the site (i.e., the spatial heterogeneity of measurement within the site).
    Expert estimateEstimate made by expert familiar with site
    WTD_STATISTIC_NUMBER
    Optional
    integer numberNumber of observations used to determine water table depth statistic
    Number of observations (samples / replicates) used to calculate the STATISTIC for the reported measurement.

    BADM Examples

    Choose a variable marked with to show examples of how to submit and interpret these BADM. See BADM Basics for more details.

    Combinations of variables must be unique. Read more: .

    Required Variable
    Optional Variable
    Combinations
    Examples
    Water Table Depth
  • WTD
  • WTD_STATISTIC
  • WTD_STATISTIC_METHOD
  • WTD_STATISTIC_NUMBER
  • WTD_APPROACH
  • WTD_DATE
  • WTD_DATE_UNC
  • WTD_COMMENT
  • Click a variable marked with to see examples.
    No example currently available

    STATISTIC Variables

    Many BADM groups have a required and several optional STATISTIC variables. Specific examples of their use are given after an overview the variables basics.

    STATISTIC Basics

    BADM typically describe site-level descriptions and observations. The STATISTIC variables allow for full characterization of the reported information if desired. BADM groups, such as canopy height, LAI, soil chemistry, phenology, and biomass, contain the following STATISTIC variables:

    var_STATISTIC
    Required
    The type of value reported.

    Options:
    Mean, Minimum, Maximum, Percentiles
    Standard Deviation, Measurement Uncertainty
    Single observation

    var_STATISTIC_METHOD
    Optional
    The method of aggregation used to generate the statistic.

    Options:
    Aggregate of individual observations
    The statistic is aggregated from individual observations located within the site. Observations may be grouped into sample areas (e.g., plots) within the site but those groupings are ignored.

    Statistics generated by this approach may represent spatial characteristics of the measurement within the site (e.g., spatial heterogeneity) and/or characteristics due to other factors (e.g., population variability).

    Aggregate of sample aggregates
    The statistic is aggregated from aggregated individual observations located in sample areas within the site. For example, individual observations are made in 5 sample plots within a site. “Aggregate of sample aggregates” is used if a plot statistic (e.g., Mean) is first calculated, and then the plot values are aggregated to calculate the site statistic.

    Statistics generated by this approach are often used to highlight the spatial characteristics within the site (i.e., the spatial heterogeneity of measurement within the site).

    Expert estimate
    Estimate made by expert familiar with site

    See the Examples for more details.

    var_STATISTIC_NUMBER
    Optional
    The number of observations used in calculating the statistic.

    STATISTIC Examples

    Example 1: DBH calculated from a single sampling area
    Example 2: DBH calculated from 8 plots
    Example 3: DBH calculated from randomly selected trees within the site
    Example 4: Biomass calculated from 8 plots each with 5 sub-plots
    Example 5: Soil carbon calculated from replicate samples at 10 locations

    Example 1: DBH calculated from a single sampling area


    For DBH observations of individual trees in a single sample area at the site:

    STATISTIC* = Mean, Minimum, Maximum, Percentiles, or Standard Deviation
    STATISTIC_METHOD = Aggregate of individual observations
    STATISTIC_NUMBER = # of individual samples

    * Minimum, Maximum, and Percentiles should only be calculated if the sample size is adequately large.

    Example 2: DBH calculated from 8 plots


    For DBH observations of individual trees in 8 sample plots at the site:

    If the individual DBH observations are first aggregated at the plot level and then the plot values are are used to calculate the site-level STATISTICs to highlight spatial variability:

    STATISTIC* = Mean, Minimum, Maximum, or Standard Deviation
    STATISTIC_METHOD = Aggregate of sample aggregates
    STATISTIC_NUMBER = 8

    If the individual DBH observations are aggregated across all plots to calculate the site-level STATISTIC:

    STATISTIC* = Mean, Minimum, Maximum, Percentiles, or Standard Deviation
    STATISTIC_METHOD = Aggregate of individual observations
    STATISTIC_NUMBER = # of individual samples

    * Minimum, Maximum, and Percentiles should only be calculated if the sample size is adequately large.

    Example 3: DBH calculated from randomly selected trees within the site


    For DBH observations of individual trees randomly selected at the site:

    STATISTIC* = Mean, Minimum, Maximum, Percentiles, or Standard Deviation
    STATISTIC_METHOD = Aggregate of individual observations
    STATISTIC_NUMBER = # of individual samples

    * Minimum, Maximum, and Percentiles should only be calculated if the sample size is adequately large.

    Example 4: Biomass calculated from 8 plots each with 5 sub-plots


    For Biomass observations collected from 5 sub-plots located in each of 8 sample plots at the site:

    In many cases, the sub-plot biomass observations are first aggregated at the plot level. Then the plot values are are used to calculate the site-level STATISTICs:

    STATISTIC* = Mean, Minimum, Maximum, or Standard Deviation
    STATISTIC_METHOD = Aggregate of sample aggregates
    STATISTIC_NUMBER = 8

    If pseudo-replication or spatial autocorrelation is not an issue, the sub-plot observations may be aggregated across all plots to calculate the site-level STATISTIC:

    STATISTIC* = Mean, Minimum, Maximum, Percentiles, or Standard Deviation
    STATISTIC_METHOD = Aggregate of individual observations
    STATISTIC_NUMBER = 40

    * Minimum, Maximum, and Percentiles should only be calculated if the sample size is adequately large.

    Example 5: Soil carbon calculated from replicate samples at 10 locations


    For replicate soil carbon observations at 10 randomly-selected points within the site:

    To calculate Mean, Minimum, Maximum, Percentiles, and Standard Deviation, the replicates at each location should first be averaged. Then the average values at each location can be used to calculate the STATISTIC:

    STATISTIC* = Mean, Minimum, Maximum, Percentiles, or Standard Deviation
    STATISTIC_METHOD = Aggregate of sample aggregates
    STATISTIC_NUMBER = 10

    * Minimum, Maximum, and Percentiles should only be calculated if the sample size is adequately large.

    The average difference between the replicates can be used to estimate the Measurement Uncertainty:

    STATISTIC = Measurement Uncertainty
    STATISTIC_METHOD = Aggregate of individual observations
    STATISTIC_NUMBER = 10

    DATE and DATE_UNC

    DATE

    Many groups require DATE to describe the time period that the metadata or ancillary data represents.

    Dates should be entered at the precision known and most suitable to the observation. Supported precision include year, month, day, and minute in ISO formats: YYYY, YYYYMM, YYYYMMDD, YYYYMMDDHHMM.

    Typical resolutions used for DATE are year, month, or day: YYYY, YYYYMM, YYYYMMDD.

    DATE_UNC

    Uncertainty in the DATE is an optional variable that can also be reported.

    Report a date uncertainty that is commensurate with the DATE reported. For example if a day is reported for the DATE, date uncertainty should be on the order of days rather than months or years. If a year is reported for the DATE, date uncertainty should be greater than a year.

    Customize and Download CSV for BADM Submission

    After selecting your desired variables, download the customized CSV file for submission of BADM. For additional submission details, see BADM Submission Instructions. See BADM Basics for general BADM details.

    Multiple entries of this BADM group can be reported per site. However, combinations of variables must be unique. Read more: . See BADM Basics for more details.

    Required Variable
    Optional Variable
    Combinations
    Examples
    Open/Close
    Select
  • Water Table Depth
    Required Optional
    WTD
    WTD_STATISTIC
    WTD_DATE
    WTD_STATISTIC_METHOD
    WTD_STATISTIC_NUMBER
    WTD_APPROACH
    WTD_DATE_UNC
    WTD_COMMENT
  • Submit completed CSV file at Upload Data using the BADM option (login required).