Yes, I know that Kaohsiung is officially known as a city but I still consider the regions with hiking trails and waterfalls to be Kaohsiung County.
Kaohsiung is where I have lived since I moved to Taiwan in 2009. 2009 was also the year that Typhoon Morakot destroyed much of the infrastructure in the mountainous area of Kaohsiung. For several years access was limited in the Namasia and Taoyuan (district) regions but access is slowly being restored and trips are being planned to find some of these waterfalls. It’s fairly common for southern Taiwan to not get any rain from November until April and many of the waterfalls in this area dry up by January.