The park area extends above the ravine where you can cross on a rope bridge and the lookout is just divine from the top . There are picnic shelters and restrooms as well as a A-frame bungalows with cooking facilities, toilets, bedding can be rented and you can also camp here. Well worth a look especially after the rainy season where the water is gushing down rather than trickling and the waterfall area will be quite deep for at least a nice cool swim in the pools or at the best a couple of jumps from the rocks above.
I will absolutely be returning to Tomigawa Ravine Nagasaki again in October/ November to see the Autumn foliage in full bloom. The amount of Maple trees in the area are beyond normal and I am sure that the leaf changing colours will be intense as well as impressive to the eye.
One word of caution though, mosquito's can be harsh and appropriate clothing is necessary especially in June and July when the rainy season is at its peak.
Come and check out Tomigawa Ravine Nagasaki on a map: