Updated 28th October 2016
A large, deep pool approached down a steep slope. This is associated with the main Riaño resurgence, site 575 but there appears to be no passable route between them. The Pozo Negro has been dived in the past to where it became too narrow. The underwater investigation was repeated in April 2016 (video) and the route forward appeared to be blocked with vegetation.
A small resurgence also drains into the pool and this is documented on the April 2016 video. See the resurgence page for more information.
References: anon., 2016b (Easter logbook)
Entrance pictures : from the resurgence page
Underground picture :
Video : Dive and small resurgence - April 2016 (YouTube)
Detailed survey : sketch on resurgence survey (Easter 2016)
Line Survey :
On area survey :
Survex file : to water level as surface survey on resurgence page