The WooDDAM field protocol is a fast, reproducible, and cheap way to measure wood jam characteristics and monitor wood jam change through time (dynamics). Field data collection can be done by 1-2 people using only basic survey equipment. If you can identify and measure bankfull channel dimensions and take pictures, you can survey wood jams using this protocol, contribute data to the database, and obtain predictions of wood jam dynamics.
We recommend first reading Scott et al. (2018, preprint) or Scott et al. (2019, post-print) before using WooDDAM to get a better idea of the purpose of the tool and the reasoning behind it.
The field survey protocol consists of initial surveys to describe wood jam characteristics, followed by optional repeat surveys of wood jam dynamics conducted after some period during which high flows might be expected to occur (e.g., spring for a snowmelt-dominated watershed). Resurveys are not necessary for obtaining wood jam dynamics predictions but are necessary for contributing to the database, which will help improve both the database and the predictive models for everyone who uses them.
A tool to measure bankfull channel width, depth, and slope (e.g., laser rangefinder, level and tape, etc.)
A tool to record data (water-resistant smartphone highly recommended, using the Data Entry Spreadsheet linked above; or a water-resistant notebook or the Printable Data Collection Spreadsheet linked above)
A GPS (water-resistant smartphone highly recommended, but a separate GPS unit will work)
A camera (water-resistant smartphone highly recommended, but a separate camera will also work)
We recommend the following survey setup, which satisfies all the above requirements:
- A laser rangefinder that measures distance, tilt/inclination, and azimuth (e.g., Trupulse 360, Haglof Laser Geo)
- A water-resistant smartphone/tablet, or one with a water-resistant case, with a camera and GPS, loaded with:
- offline maps (topographic and imagery, ideally, using an app like OnX, Gaia GPS, Backcountry Nav Pro, or CalTopo)
- pictures from the previous WooDDAM survey, if doing a resurvey
- the Data Entry Spreadsheet linked above, with data from the previous survey (downloadable from the database page, if previously submitted to the database)
- A belt/sling case for the smartphone/tablet and laser, to prevent drops
How to Measure Wood Jam Characteristics in the Field
Collecting the field data necessary to run the statistical model is relatively simple. Although there are many variables to collect, the vast majority of them are binary yes/no questions about the jam or its environment. Typically, after familiarization with the protocol, most jams take between 5 and 15 minutes to survey.
- Read through the Table of WooDDAM Variables linked above. Most of the variables are self-explanatory (e.g., does the jam touch the bed), but we recommend printing and carrying this table in the field to clarify uncertainties.
- After familiarizing yourself with the variables used to characterize wood jams, identify jams (usually via aerial imagery or field reconnaissance) to be surveyed, based on your objectives. For instance, if monitoring a restoration site, it may be useful to identify and monitor all natural and engineered jams within, shortly upstream, and shortly downstream of the restoration segment.
- With jams identified, begin characterizing jams in the field. You’ll need the equipment listed above. When recording data, we recommend using 1/0 coding for binary variables (1 = yes, 0 = no), as we find this to be the fastest and least error-prone method for recording data in the field. However, you can also use y/n or yes/no, as preferred.
Regardless of the field data collection method, data must eventually be entered into the Data Entry Spreadsheet linked above (which can be used both for obtaining model predictions of wood jam dynamics and contributing to the public database). This spreadsheet has conditional formatting rules to help with data entry. For instance, if a jam touches both the outer and inner banks, it must also span the channel. Red highlighting in a cell after you fill it in indicates that the measured data don’t make sense and should be checked.
After returning from the field, enter data into the spreadsheet for data submission linked above (if not already), and use the database submission page to submit data to the database. Once the database contains more data, predictive models will also be open to public use and will be driven by this same data submission spreadsheet.
Please feel free to contact Dan Scott with questions.
How to Resurvey Wood Jams to Measure Wood Jam Dynamics
After measuring wood jam characteristics for an initial survey, you must resurvey wood jams after some time (and perhaps high flows) have passed to measure wood jam dynamics. Doing this enables wood jam monitoring, contributing more complete data to the database, and contributing to improving the machine learning models of wood jam dynamics. Collecting and submitting wood jam resurvey data here helps your understanding of a system and can benefit others who use WooDDAM.
To conduct a resurvey:
- Resurveys should be conducted after a period of time during which you expect high flows to occur (e.g., spring and early summer for snowmelt-dominated watersheds, or late summer for monsoon-dominated watersheds).
- To prepare for a resurvey, make sure you have all the tools used for an initial survey, as you may need to re-measure channel geometry and wood jam characteristics. To facilitate resurveys, we provide access to the WooDDAM database records that require resurveying on the database page. There, you can find an option to download all rows in the database that require resurveying, then simply delete the rows you don’t plan to resurvey. Once filling out this spreadsheet, you can then resubmit it, again on the database page, to submit your resurvey data.
- To detect change, download the pictures taken of wood jams during the initial survey to a mobile device (or print them out) to facilitate comparison in the field. Use the picture time and date recorded in the database to identify pictures taken during the last survey of a given wood jam.
- In the field, start by taking pictures of each wood jam you’d like to resurvey. Like the initial survey, try to take pictures that capture the entirety of the jam from multiple angles, so that most or all logs are visible in at least one, but ideally more than one, picture.
- Compare the jam to the pictures taken during the last survey, and note whether the jam has mobilized, accumulated wood, lost wood, contracted, or expanded (see Table of WooDDAM Variables linked above)
- Using the pictures from the last survey, look for evidence of the maximum stage since the last survey (flood deposits, pushed vegetation, scour marks, etc.) and estimate whether the flow was below, near, or above bankfull stage. Enter this under the “qual_mag_high_flow” column.
- Using the downloaded WooDDAM database on a mobile device, check that the jam still has the same characteristics (and that the channel dimensions have not significantly changed) compared to the initial survey. Note that a jam may experience change (e.g., accumulate wood), without any of the wood jam characteristics variables in the database actually needing to be changed.
- If any variables have changed, mark a 1 (for yes) in the “recharacterization_needed” variable, then record which variables have changed in the “notes_resurvey” column. This will be used to update the new entry in the database (each survey/resurvey of a jam generates a new row in the database). Remeasure any variables that have changed and note those remeasurements in the “notes_resurvey” column
- Back in the office, fill out the resurvey components of the spreadsheet (everything right of “notes_survey”), then submit the data to the database. Shortly after submission, the data will be verified, integrated into the database, and new rows created to facilitate further resurveys.