Installing GDAL via pip causes sometimes problems. We recommend downloading the library from
as GDAL-3.0.4-cp37-cp37m-win_amd64.whl (or a later version depending on your Python version) and installing them as:
pip install C:/Users/XXXXX/Downloads/GDAL-3.0.4-cp37-cp37m-win_amd64.whl
Sometimes problems occure if you have installed GDAL separately (or a software did, like QGIS)
If not, sometimes it comes from the fact there are several Python versions installed on the computer or if GDAL is already installed by another software. You can also try to go inside your Python folder (the one you are using to run CWATM ) and from this folder, try to call you gdal library (or try to run CWatM). To check, if your GDAL library is well linked to your Python version.
In cmd: "python -V" will give you the Python version. "pip list" will give you all the installed libraries for this Python version (type "pip -V" to check that pip is linked to right Python version)
Hope it will help,