Circular route around the intermittent karst springs

Itinerary

• We join the unmarked path at Hereg-rét to the K+ marker, turning right on it.
• At the first fork we turn left and downwards following the K● markers to reach the Imó-kő.
• In the Lök valley, switching to the K marker, we touch the Fekete-len spring and step onto the asphalt at Tamás-kút.
  
• On the asphalt we follow the K+ sign which leads back to Hereg-rét.

Detailed description of the route

Under the ridges of the plateau

An unmarked but clear path starts north from the parking lot; at the edge of this clearing it joins the K+ marking. At the pleasant, elongated Hereg-rét, at the northern end, we find the Lénárt spring (named after János Lénárt, a teacher from Heves, co-author of Bükk and Mátra guides, and an active nature traveler), and in the left corner there is a spacious rain shelter (with a fire pit in front). As we step under the narrow corridor framed by trees at the edge of the meadow, the view opens up delightfully and sadly at once: opposite us the rocky escarpments of the Bükk plateau shine white, we can spot the Tar-kő (left) and the Három-kő (right) cliffs with rocky grasslands. (The limestone layers folded near vertical on the edge of the plateau were supported underneath by more quickly eroding shale rocks, and when the erosion caused insufficient support, the limestone broke off in large blocks. This series of scars forms the stone formation's outline.) At the same time, the forest view is depressing: we look at a clearcut, and on both sides there are more logging patches, while the grown-up stands are cut into mosaic patches by previous logging boundaries. The unnatural straight lines and bare slopes can be observed for a while longer (our next section of the route will lead downwards to the left), until we enter under the trees and the wide bulldozer road bypasses the valley head feeding Borz-kút spring.

Lush valley adventures

Soon a fork puts us at a crossroads, where we must choose the dense, descending K● path to the left. Although close to Imó-kő, expect unpleasant minutes: the wet valley bottom is covered with tall nettles, often mud, and due to regrowth it is a dense thicket. Additionally, we tread a rarely traveled path, so the lead hiker sometimes has to cut a passage through the thicket (which luckily at least lets us through easily). Don't give up, behind Imó this lush forest environment becomes magical: the valley narrows, small rubble patches appear on the ground (even underfoot), and moss-covered rock blocks rise on the right above our head (thus we can understand the origin of the rock debris). Old trees, rich undergrowth, fallen trunks, and an extremely narrow path create a primeval forest atmosphere, where the wilderness is finally near what it would be without human interference.

The Imó-kő and its spring

Then we descend a few meters suddenly, turning right to reveal the huge, dazzlingly white limestone ridge of Imó in sunshine. In front, the gnarled roots of an ancient tree guide our eye to a dark, narrow crevice, from which water occasionally bursts out with a great roar (hence the name Lök valley). During dry periods, only cool air escapes from the mountain's core, so we can venture a few meters in - this is especially refreshing in summer heat. (Only move within the first visible meter, after that the passage slopes and steps segment it, so it is dangerous!) The spring cave has been explored for 85 meters in length and 23 meters in depth, but above it there are previous spring outlets in the rock. When water comes into contact with limestone on the plateau, its carbonic acid dissolves the rock — on surfacing the carbonic acid escapes, and dissolved lime precipitates. The resulting tufa fills the valley bottom below Imó over a length of about 160 meters and thickness of 1-6 meters, proving that the spring could have worked continuously in earlier times.

So why is it intermittent now? With the latest uplift of the mountain range, the highest springs have dried up, and their caves now gape dry on the plateau slopes (e.g., Pes-kő cave). Others ended up in a position where their supply branches only receive replenishment when the karst water level in the rock mass rises highest — after snowmelt or long, extremely rainy periods. (Interestingly, during sudden snowmelt the water flows fast mainly on surface routes, but intermittent springs require slow warming and gradual melting to activate.) Imó behaves similarly to the nearby Fekete-len and Vörös-kő valley springs. Sometimes no water emerges from Imó for years, but when it activates (after alleged rumbling sounds), its discharge can reach 12,000-13,000 liters per minute. The cold air streaming, thundering, newly born creek in front of our eyes is a lasting sight, enhanced further by the wild surroundings. The flow generally lasts for several weeks (up to 50-60 days).

The modest little brother

As we move away from the rock in a densely overgrown valley, we see sunshine falling on a small rocky grass patch at its top — perhaps it was a pagan sacrificial site, and its name may derive from the word "prayer." We continue through a true forest wilderness; if flowing, the creek fills the wide valley bottom. Within ten minutes we reach a fork where we turn left following the K marker. Then we ascend gently until we arrive at the Fekete-len spring: in dry conditions, only a steep blue iron pillar above it will be noticeable. When active, it is an interesting sight how fresh creek water pours out from its small rock ring and meanders on its long mountain path. This is the least known of the three known intermittent springs, as it lacks all extremes, yet mossy rock blocks and the mature beech forest form an impressive decor around it. (The blue artificial structure hides an old scientific drilling hole allowing karst water examination.)

Back to the meadow

A short walk from here ends the climb, where we step onto the Eger–Miskolc country road. We can rest at a rain shelter or draw water from Tamás-kút (this springs on the far side of the asphalt below its level). Behind the fence, the Tamáskúti Guesthouse awaits guests as a key lodge (after advance registration), and our route invites us left along the road. Let's be cautious, as the curves hide us from cars which often approach at dangerously high speeds. Beside rocks uncovered during road construction, the tall grass hides educational trail boards explaining the geological features of the area — their professional language unfortunately does not make reading and understanding easy, nor is their roadside position appealing. Within minutes we are back at the edge of Hereg-rét, where we can now leave the asphalt (though the path is not easy to find), and end our hike at the meadow parking lot.