For all the solo exploring I do, I still second-guess my abilities when something I want to see involves a reported-as-difficult hike. However, I got tired of waiting for people who had expressed interest in tagging along for this small adventure. Thus, when the summer heatwave gave way to more bearable temperatures for a couple of days, I drove to the area. There is a convenient parking lot to leave the car without breaking any laws and since I reached it before 9:00, it was still reasonably empty, even if it was a weekend. I changed into my hiking boots and got on walking.

The spot I wanted to reach were the Mingo Negro Gullies Cárcavas de Mingo Negro, in the municipality of Alpedrete de la Sierra, within the nature reserve Parque Natural Sierra Norte de Guadalajara. Gullies are erosive landforms usually created by a combination of running water, especially torrential rains and floods, and small landslides as the sediment collapses. Gullies tend to be devoid of vegetation and generally quite vertical, as they commonly form on steep landscapes, often on sandstone or conglomerate soils. These particular gullies are the remains of an alluvial fan, an accumulation of sediments characteristic of mountain areas in semi-arid climates, which opens as it leaves a confined area, so when you look at it from above, it resembles a fan – hence the name. Gullies are common in badlands as the dry terrain is drained downwards and no vegetation holds it. They are considered to be unstable landscapes.

The Mingo Negro Gullies are on the left bank of the River Río Lozoya. A dam Presa del Pontón de la Oliva was built to contain the river in the 19th century, and though it is still standing, it could not be used as a reservoir. There is a kind of road / bridge that crosses the river and leads to the trail. It was rather easy to follow at first, but eventually I reached the steep part. Though there is technically a trail there, somewhere, the ascent is not easy to follow due to poor maintenance and water erosion. Hiking up the 370-metre slope took me about 20 minutes, and it was tiresome for but not as hard as I had pictured. To be fair though, I’ve recently bought a hiking pole and that was helpful. The terrain was a bit unstable and I kept my eyes on the ground, which is why I almost missed the first sight of the gullies (a later visit to the area revealed that I should have already seen them from right out of the parking lot, but the sun was in my eyes).

The trail is not well maintained, so plants are overgrown. If you actually want to see anything of the gullies you have to go past the “do not cross” signage, even at the viewpoints. However, you have to be very careful not to approach the border as the terrain is inherently unstable. While I was coming up, the sun masked the clay-red colour a little, which was a pity.

Though some of the online-sourced routes do so, it is also ill-advised to go into the actual gully, so I just stayed in the upper part along one of the marked trails. I did step beyond a couple of barriers, but made sure to stay a respectable distance from the border. I ventured through some of the secondary paths for pictures on my way down. However, I did not go down to the ravine, as cool as that must be, because there is a risk of collapse.

There are several trails that go to or around the Cárcavas de Mingo Negro, the most common of it circular. However, I did not feel like doing that one, which takes over four hours. I wanted to see the dramatic gullies, so once I was done around that area, I turned back using the same trail I had used to climb up. By that time it was around 11:00, and though I had seen nobody on my way there, now I started meeting people climbing. A family became quite indignant because I was not following the circular trail. Someone else had decided to tackle the hike in flip-flops. Some people are… peculiar.

There is a bar somewhere at the beginning of the route, and there were some buildings indeed. However, it was either closed – or I did not find it. I had thought I would stop for breakfast there, and then head to do something else.

I reached the Presa del Pontón de la Oliva dam again. The structure, in the municipality of Patones, belongs to Madrid’s Water Management system Canal de Isabel II and it is considered local heritage as it was the first dam built in the area. Madrid became the capital of Spain in 1561, and in the 19th century its population was growing fast. Water was obtained through fountains, whose waters came from underground water canals built 400 years prior. From the 18th century onward, architects started studying how to channel water from the nearby rivers into the city. Part of this program yielded to building the dam between 1851 and 1856 with the idea to create a reservoir. The structure is a gravity dam, with a height of almost 30 metres and a width of 72 metres at its longest. Two years after it was built, the rest of the project was completed, and water reached Madrid. However, the location had not been correctly chosen – water filtered through the rock walls to the sides and underneath the ashlar construction – and in 1904 the reservoir was closed down, so water flows freely through a tunnel under the construction.

I heeded the “flood plain, do not enter” warnings, but neither Sunday hikers nor free-range cows did. I remained on the upper area and explored a little of the area called “the balcony”, built alongside the dam to admire the structure. There is another hiking route, Ruta del Agua that starts there, but again, this was not something I wanted to tackle today, as it was my first day out after a long period at home. Had I found the bar open, I would have hiked further (the whole route is about four hours though, so it was probably good I did not).

In the end, I headed back to the car and drove off. I thought I might stop to see a windmill on the way, but I somehow missed the turn to the hamlet where it stands. I was almost surprised when I saw the road sign for the last village before home. All in all, I saw what I wanted to, and found a nice easy drive with further routes that can be taken and enjoyed in other circumstances. I think I can reasonably squeeze a couple other visits to the area.