Nullah (n.): gully, ravine
I’m reading Dervla Murphy’s Full Tilt and as she bikes through Afghanistan and Pakistan she rides along lots of nullahs.
Reference
Merriam-Webster. (n.d.). Nullah. In Merriam-Webster.com dictionary. Retrieved June 16, 2021, from https://www.merriam-webster.com/dictionary/nullah