A crater lake in a forest reserve
Lake Duluti lies east of Arusha on the road towards Moshi, inside the Lake Duluti Forest Reserve. Tanzania Forest Services places the reserve in Arumeru District, Arusha Region, and gives the lake an area of 62.3 hectares, with natural forest running right around the shore.
Two things make it genuinely unusual rather than merely pleasant. The first is the colour: TFS describes volcanic, green-coloured water, which is what gives the lake its character in photographs and in person. The second is the hydrology. No stream flows into the lake above ground at all; TFS records that it appears to be fed entirely from underground flows.
What lives there
TFS describes the forest around the lake as teeming with wildlife, and names two reptiles in particular that are worth knowing about before you walk under the trees: green mambas and monitor lizards. The mambas are arboreal and are part of the reason a guide is the sensible way to walk the shore path rather than an upsell.
The birds are the main reason specialists come. TFS names grey herons, fish eagles, cormorants, ospreys and kingfishers, which is a reasonable summary of what a slow circuit of the water produces. The bird watching guide covers how birding works in this kind of habitat, and the forest walk guide covers the walking. TFS also notes a prayer mountain within the reserve, which is in use rather than ornamental.
The depth figure
TFS states that the lake’s deepest point reaches 700 metres. That cannot be right for a crater lake of 62.3 hectares, and it is roughly two orders of magnitude out on anything comparable. The figure is reproduced here only so that you recognise it if you meet it repeated elsewhere. No depth is published on this page, because no credible one exists.
It is a useful reminder about Tanzanian forest and park records generally: the descriptive material is usually sound and the numbers sometimes are not, and a figure appearing on a single government surface is not the same as a figure being published.
How long it takes
The circuit of the shore is a short, level walk rather than a hike, and canoeing on the water is the other way the lake is normally seen — see the canoe safari guide. No authority publishes a trail length or a walking time. It fits comfortably into a half day out of Arusha, and it pairs naturally with Arusha National Park, which is in the same direction.
Common questions
How deep is Lake Duluti?
Not credibly published. Tanzania Forest Services gives 700 metres, which is not possible for a lake of this size, and no other authority publishes a figure.
What feeds the lake?
Underground flow. TFS records that no stream feeds it above ground and that the water apparently arrives from below.
Are the snakes a real problem?
TFS names green mambas among the reserve’s wildlife, which is a straightforward reason to walk the shore path with a guide who knows the trees rather than alone.