The Waimamaku River flows westward through the valley to the north of the Waipoua Kauri Forest, emptying into the Tasman Sea immediately to the south of Hokianga Harbour, in Northland, New Zealand. The river mouth is located at NZMSI N18/928114, with relevant maps being NZMSIS Sheet 2 Whangarei and NZMSI Sheets N18 and N22 (Waipoua and Taharoa).

Over the first 5 kilometres, the river descends from the Mataraua State Forest area, which contains considerable scrubland in the Waimamaku Valley. This upper section is reasonably scenic, with thick bush nearby, before opening into a cleared lower valley. There is a short gorge of approximately 1.5 kilometres below the road end that is notably scenic. A distinctive feature of the Waimamaku compared to many other Northland rivers is that a substantial length of the middle river has a bed of fine shingle rather than the soft or muddy substrate more typical of the region.

The middle and lower sections of the river are predominantly rural in character, bordered by large willow trees. Below the Main Road Bridge, the gradient decreases, the current slows, and there are long, shallow pools. Paddlers should be aware of potential willow log-jams in this section. The lower river, below the Main Road, becomes muddy and sluggish. The river mouth area is used for swimming and is a popular picnic spot.

Overall, the recreational and scenic value of the Waimamaku is rated low. The river meanders through farmland for much of its length and is not considered particularly attractive. Pack floating is seldom used on this river. Given these characteristics — slow current in the lower reaches, shallow pools, potential log-jams from willows, and a predominantly rural setting — paddlers seeking technical challenge or outstanding scenery are unlikely to find it here. The river may suit those looking for a straightforward, low-key flatwater paddle in a rural Northland setting, with the short gorge below the road end offering the most visually interesting stretch of the journey.