How to use BDWS¶
Before using the BDWS classes, some input data are required. Below is a brief description of these input files. For more information visit the preparing input data page of the documentation. Note: it is recommended that all inputs be clipped to the valley-bottom extent. This extent can be determined with the V-BET tool.
- Shapefile created by the BRAT model. Must contain single-part features. Multi-part features will not be processed by
- Digital Elevation Model (DEM) for area of interest. Spatial resoultion of 10 meters or less is recommended.
- Rasterized stream network raster. Generally created by applying a threshold to a flow accumulation raster. It is recommended to represent stream network cells with a value of 1 and all other cells with a value less than 1.
- Flow direction raster (D8) derived from the input DEM. Both ESRI and TauDEM D8 flow direction rasters are supported.
Currently, it is recommended to use BDWS to create python scripts to model beaver dam water storage. BDWS has been developed and tested using the PyCharm IDE. Below are brief examples describing how to use BDWS classes. For more detailed examples of BDWS implementation visit the tutorials page of the documentation.
BDWS code is hosted at https://github.com/konradhafen/beaver-dam-water-storage in the bdws.py and bdflopy.py files. Classes can be imported as follows.
from bdws import* from bdflopy import *
BDLoG takes a vector stream network created by BRAT and generates
locations of individual dams on a rasterized stream network.
BDLoG requires a shapefile created by BRAT,
a DEM, a rasterized stream network, path to output directory, and a proportion of maximum
dam capacity to model. The following code will initialize
BDLoG, generate dam locations
and dam heights, and save output files for a maximum capacity (1.0) scenario.
model = BDLoG('path/to/brat.shp', 'path/to/dem.tif', 'path/to/fac.tif', 'out/dir', 1.0) model.run() model.close()
BDSWEA uses dam locations and dam heights generated by
BDLoG to estimate the area and surface volume
created by beaver dam construction.
BDSWEA requires output files (see below) from
BDLoG for initialization.
BDSWEA initialization requires
a DEM, a flow direction raster derived from the DEM, a rasterized stream network, the dam ID raster created by
BDLoG, an output directory, the dam location and attribute shapefile created by
BDLoG. The following
code will estimate beaver pond inundation and write files necessary for parameterization of MODFLOW.
model = BDSWEA('path/to/dem.tif', 'path/to/fdir.tif', 'path/to/fac.tif', 'path/to/id.tif', 'out/dir', 'path/to/pts.shp') model.run() model.writeModflowFiles() model.close()
BDflopy implements the existing FloPy module to automatically
parameterize MODFLOW-2005 to estimate changes to goundwater storage resulting from beaver dam construction.
BDflopy requires the path to a MODFLOW-2005 executable, path to directory of input rasters, path to directory
BDSWEA outputs, path to directory to write outputs, and name of DEM file in inputs directory for initialization.
The following code will initialize
model = BDflopy('path/to/modflow.exe', 'input/dir', 'bdswea/out/dir', 'out/dir', 'dem.tif')
BDflopy.run() requires additional parameters. Horizontal and vertical hydraulic conductivity (as a raster,
numpy array, or single value), a factor to convert conductivity values to meters per second, the fraction of soil
available for water storage (e.g. field capacity or porosity), and a factor to convert the soil fraction to a proportion.
This will write MODFLOW’s input files, run MODFLOW, and generate output raster files.
BDflopy.run() can be implemented as follows.
model.run('path/to/hk.tif', 'path/to/vk.tif', 1.0, 'path/to/frac.tif', 1.0) #or model.run(1.0, 1.0, 0.000001, 20.0, 0.01)
Then close the class object.
BDLoG generates the following files:¶
A shapefile containing generated beaver dam locations and information about each dam. This file is updated with estimated area and volume of modeled ponds by
- damType: If the dam is primary or secondary. Primary dams are taller than secondary, this classification determines which distirbution is used to model dam heights.
- ht_lo: The 0.025 quantile of the values selected from the dam height distribution. Modeled as the low dam height scenario.
- ht_mid: The 0.5 quantile of the values selected from the dam height distribution. Modeled as the median dam height scenario.
- ht_hi: The 0.975 quantile of the values selected from the dam height distribution. Modeled as the high dam height scenario.
- area_*: Area of the pond created by modeling the dam under a given height scenario.
- vol_*: Volume of the pond created by modeling the dam under a given height scenario.
- Other fields: For use in adjusting dam heights so pond volume fits within the prediction intervals of an empirical model. This is not yet implemented in the python version.
- Rasterized locations of generated beaver dams. Each beaver dam location is represented by a single cell with a number corresponding to the FID in ModeledDamPoints.shp.
BDSWEA generates the following files:¶
- depLo.tif, depMid.tif, depHi.tif
- Depths of modeded beaver ponds for low, median, and high dam heights.
- The height of a cell above the dam it drains to. Used for determining pond dephts.
- FID of the dam a cell drains to. Used to calculate area and volume of modeled ponds.
- WSESurf_lo.tif, WSESurf_mid.tif, WSESurf_hi.tif
- The sum of the input DEM and each pond depth raster. Used to parameterize the top of the MODFLOW modeling domain.
- head_start.tif, head_lo.tif, head_mid.tif, head_hi.tif
- The intersection of the rasterized stream network and each WSESurf_*.tif file. This represents the water surface elevation of the stream and beaver dams. Used for MODFLOW parameterization.
BDflopy generates the following files:¶
- start.*, lo.*, mid.*, hi.*
- Input files written by
flopyas inputs to MODFLOW, or output files written by MODFLOW.
- ibound_start.tif, ibound_lo.tif, ibound_mid.tif, ibound_hi.tif
- Definitions of the model domain (active, inactive, and constant head boundaries) for each MODFLOW simulation.
- shead_start.tif, shead_lo.tif, shead_mid.tif, shead_hi.tif
- Starting hydraulic head values for each MODFLOW simulation.
- ehead_start.tif, ehead_lo.tif, ehead_mid.tif, ehead_hi.tif
- Modeled hydraulic head values (water table elevation) for each MODFLOW simulation.
- hdch_lo.tif, hdch_mid.tif, hdch_hi.tif
- Estimated change in groundwater elevations from construction of beaver dams with low, median and height heights. Obtained by subtracting ehead_start.tif from water table elevations modeled with beaver pond influence.
- hdch_lo_frac.tif, hdch_mid_frac.tif, hdch_hi_frac.tif
- hdch_*.tif multiplied by the water holding capacity of the soil (e.g. field capacity or porosity).