Expedition Name (& Club): Tresviso 2016 (Bradford Pothole Club)

Destination country: Spain
Region: Cantabria

Lat: 43.2573 Long: -4.6688 Elevation: 900 m
MEF funding: none

Leader: Mr Phil Walker

Brief Expedition objectives:

List a short summary of the main Expedition objectives.

Cueva del Nacimiento is a large resurgence cave, with a catchment area of 37km^2 and a possible vertical range of nearly 1500m. Caves found in the high plateau have been dye traced to Nacimiento, although continued and hard exploration of the deep vertical potholes (CS-9 being the deepest at ~1200m) has failed to find the elusive connection.

However, the ancient Nacimiento lends itself to the unusual approach of 'upwards' exploration. With many steep slopes, or ramps taking the vertical range of the cave to over 500m (as of 2015), with a strong draft present throughout the system.

In brief the objectives of the 2016 trip will be to establish a more permanent camp near the far reaches of the cave to allow efficient and continued upwards exploration of Nacimiento. This will be undertaken alongside the downwards exploration of nearby surface potholes.

How can the GPF support your Expedition?:

Please explain the aspects of the trip which make it eligible for Ghar Parau funding.

The exploration in 2015 required a strong team to camp in the further reaches of the cave (Death Race). This is a remote location and ideally would benefit from a more permanent camp than used over previous expeditions, allowing more exploration gear to be carried. In 2015, every single hanger/bolt taken in to the cave was used.

In addition, it is a gear hungry place, with poor rock quality and lots of traversing/ bolt climbing requiring large amounts of rope, hangers and bolts.

Any grant aid will go directly towards the exploration of the cave.

Detailed description of objectives:

Give a more detailed account of the purpose of the trip, including any particular known caves you intend to visit, specific areas where you will explore for new cave, and scientific experiments you will attempt.

Cueva del Nacimiento is a large resurgence cave in the valley below Tresviso. Originally explored in the 1970's and 80's it was pushed to a terminal chamber 'Death Race 2000', ~400m above the entrance. Interest was re-kindled in 2009 with a lot of work put into to regaining the original route over the following years and climbs above Death Race were started.

During 2015, a two week expedition saw some substantial progress in the cave, with over 1km of new cave explored and surveyed, much of this beyond the 'terminal' Death Race Chamber. Of particular interest was a series of ramps, containing a significant draft, beyond Death Race with a height gain over over 100m from Death Race. This new series of passages aligns with the general trend of the system and is the obvious continuation of the high level route, there are many new leads (mostly short climbs) in this region of the cave. In addition, a very large sump pool (40x10m) was found ~200m below Death Race, with a possible by pass noted. The 2015 extensions can be seen on the attached survey, the two major leads are 'Jurassic World' and the 'Pina Colada Sump' on the far left.

Main objective
The objectives of the 2016 trip will be focused around the further exploration these exciting leads at the far end of the cave, with the ultimate goal of a higher entrance being located. It is expected to require bolt climbing from several strong teams rotating in camp.

Diving objective
In addition to exploration in the far reaches a small, and mostly self sufficient diving team will be focussing their efforts on 'Parting Friends' an un-passed sump in the main river passage. They also have a secondary objective of exploring a sump in 'Cowshead Caverns', a fairly extensive cave system presumed to be separate to the main Cueva del Nacimiento drainage - excellent possibilities here!

Secondary objectives
Further possible objectives include exploration of the plateau potholes in the vicinity above the 2015 extensions - on the Sierra de la Corta - and searching for a possible mid level route through the cave (between 'Howling Hole', 'I Love Horses' and 'Fools Paradise' - middle of the attached survey).

Previous work in this area:

Give details of any previous work in this area by your own and other teams. Include references to reports and articles published on the area, and the names of any local cavers or academics with whom you have discussed the Expedition.

All previous work in the region has been well documented as part of the project. Detailed reports of previous exploration in the catchment area (and immediate vicinity) can be found here - http://www.picosandaracaving.info/expeditions.html# whilst an overview can easily be seen here - http://www.picosandaracaving.info/timeline.html#.

In short, Cueva del Nacimiento was originally explored by Lancaster University Speleological Society in the 1970s and briefly re-visited in the 1980s when the terminal chamber, Death Race 2000 was reached. Here is seemed the nature of the system changes from steep ramps to a large vertical shaft and no obvious progress was made. During this time further exploration was being made on the surface plateau (by LUSS, Adi Kami and eventually SWCC) with several very deep (>1000m) caves being found. However, whilst many were very deep, few were trending towards Nacimiento (despite positive dye traces).

Whilst Adi Kami were pushing CS-9, British exploration in the region waned. However, the increased use of drills over hand bolting has made the further exploration of the more vertical further reaches of Nacimiento viable and exploration was again possible. Over 2011/12 a lot of hard work was put in regaining the terminal chamber (over 300m of climbing) and progress began on climbing the pitches.