Nidderdale Caves

Water from the moors above Angram and Scar House drains into the reservoirs, which in turn feed the River Nidd. Below Scar House dam the Nidd flows east then turns south, and shortly after disappears underground through a series of small fissures in the exposed limestone inlier. All the water from the various fissures enters the large stream passage of Manchester Hole. The underground stream can be followed along an impressive 3 to 4 sq m passage to the equally impressive massive blockfall cavern of the Main Chamber. Faulting here is not only responsible for the blocks but has allowed incursions of more than one stream to aid the process of block fall. At present one small stream enters at the southern end, but previous flooding such as in 1998 has opened up choked passages, allowing a large volume of water to enter Main Chamber. A huge section of the mud bank in that chamber collapsed and the flood subsiding refilled the passage. This process of opening and closing of inlets has probably been repeated many times over the centuries. The stream at the base of the chamber flows amongst fallen blocks to enter a passage of fine proportions, but the roof soon dips to where the stream enters a low area known as ‘the grovel’. The roof quickly rises again in Fossil Passage, where a narrow but high passage can be followed round more than one bend to a wider section. Here a small tube high up on the left leads to a permanently flooded section (static sump) 46m long that connects with Goyden Pot cave at Pillar Pot. The stream flowing through Manchester Hole does not connect with this static sump but instead flows onwards for a few metres to the ‘duck’. At the duck the stream make a sharp right turn almost flowing back on itself through a hands and knees crawl with limited airspace. After a few metres of the ‘duck’ the passage once again enlarges and the stream then flows on for a few more metres to enter downstream sump 1. This sump is 15m long and enters Divers Chamber. The stream flows out of the chamber along a short passage to enter sump 2, a small constricted passage that enters the Lesser Stream area of Goyden Pot.

In the Lesser Stream passage of Goyden Pot the many fractures in the rock allows the stream to diverge and flow in different directions. Sandstone boulders are washed in from the surface through the numerous inlets in this area. These inlets are also opened and closed through the action of flooding. The various streams quickly unite and flow amongst the large boulders that form the floor of yet another impressive large breakdown chamber, Goyden Main Chamber. The stream then flows out from under the boulders and over the cascades to flow along the huge Main Stream Passage, 25m high in places and typically 6m wide for more than 150m, to where it flows into sump 1, 20m long. The river flows out of sump 1 past October Passage, which steals a small amount of the river. It then flows along another huge gallery into sump 2, 6m long. From there the river flows along the largest of the stream passages in Goyden to sump 3, 27m long. Here the river flows into Bridge Hall, where a small inlet on the left enters, probably the water from October Passage but as yet unconfirmed. At the far side of Bridge Hall is sump 4, just 2m long, and then a short section of passage to sump 5, about 57m long, and a lake airbell with choked inlet in the roof. Sump 6, 12m long, leads from the airbell to a short passage with a roof passage leading into the Aquamole series that can be entered via Frog Pot. At the end of the short passage sump 7 is a low obstructed sump that connects with the upstream sump 2 and sump 1 of New Goyden Pot.

The water flowing from upstream sump 1 flows along a very fine round railway tunnel sized passage to a bend, where a significant additional stream enters on the left. This is from Frog Pot and is the New Stream water from New Stream sump in Goyden pot. The combined waters flow along the huge tunnel to a short low flooded section, Middle Sump. At the far side of this sump the water flows for a short distance and then enters downstream sump 1. Divers have explored beyond sump 1 through another seven sumps. The water from this farthest point of exploration travels just over a kilometre to the furthest explored point of Nidd Head Resurgence. The Nidd actually resurges from three locations, the North West Rising, Main Rising and South East Rising. As the name suggests most of the water rises from the Main Rising and this has been explored by divers for over 850m. The North West Rising is presumed to flow from a point 119m into the Main Rising. The water from South East Rising has been explored for over 120m and is also thought to connect with the Main Rising.

The risings combine. The river shortly afterwards is joined by How Stean Beck and flows down Nidderdale to Gouthwaite Reservoir.

The Goyden system floods as a result of excess water overflowing the Scar House dam. This can happen not only following significant rainfall but also by wind action from a westerly or near westerly direction. The wind on a full or nearly full reservoir whips up waves on Scar House Reservoir sending water over the dam that on occasions has pushed down the valley more than one metre depth of water from the reservoir. The caves can therefore flood in a period of no rain but by wind action alone. The water flowing down the valley is typically greater than the capacity of the fissures taking water into Manchester Hole. So most of the water flows past the Manchester Hole and onwards to Goyden Pot Main entrance. At various times old abandoned inlets are re-opened and re-closed by the flood waters allowing water to enter the far reaches of Manchester Hole and Lesser Stream passage of Goyden Pot. The increased flow into Manchester Hole and a pooling effect by the constricted sump 2, with possibly reopened inlets, causes the far end (between the ‘grovel’ and the ‘duck’) of Manchester cave to flood, at times very quickly. Water flowing into Goyden Pot Main entrance falls into the Main Chamber from high level passages from the first and then second and eventually the third window. This water joins the river flowing from Manchester Hole over the cascades and along the Main Stream passage. The swollen river flows through to sump 7 which due to its constricted nature causes the water to back up and flood the system from there all the way back. The rising water enters the roof passage between sump 6 and sump 7 taking with it much debris. The water flows along this passage into Toad Hall and through the 30m sump into Frog Pot, where it joins the New Stream water from Goyden Pot, New Stream sump. The combined flood waters flow into New Goyden Pot via Main Stream inlet to join the increased water from upstream sumps 1 and 2 in New Goyden. This water backing up through the system is first seen to rise in Frog Pot then Guscott Pot, Limley Pot, Church Pot and then Goyden Pot. By this time the far end of Manchester Hole has already flooded by the mechanism mentioned before. The whole system floods completely with the exception of Manchester Hole from the entrance to the ‘grovel’. The latter has been confirmed by leaving markers in the roof of Manchester Hole amongst the flood debris. The markers remained even in very high flood conditions in the rest of the system, which suggests that the flood debris present in the roof dates from before the construction of Scarhouse reservoir. Once Goyden is full water is forced past Goyden Pot Main entrance down the valley on the surface past the village of Lofthouse through to Gouthwaite Reservoir. In severe floods water mushrooms out of Church Pot, Limley Pot and New Goyden Pot, while Guscott Pot and Frog Pot still take water. In the most severe floods the River Nidd rises enough to lap into or small flow into Manchester Hole main entrance.