The Levada do Caldeirão Verde is one of the oldest of the long levadas on the island - its construction was started in 1796. There are very severe drops down on the one side but these are well protected with railings. However, heavy rain or rockfalls can sometimes wipe some of these out and people with vertigo might not like the walk which has 4 tunnels. However, it is a relatively easy way for walkers to penetrate the Laurissilva Forest and reach the spectacular central valleys and gorges of this volcanic island. PLEASE TAKE CARE especially if you try the route unaccompanied.
LEVADAS There is abundant water on Madeira although most tourists do not see a lot of rain. On the north coast it rains much more than on the south and the greater the altitude the more it rains. The climate is mild all year round, averaging 63 oF in winter to 71 oF in summer but the warmest slopes are on the south side of the island so that Funchal experiences temperatures around 16 oC to 26 oC, exceptionally 35 oC. From the early days of colonization, water was sourced in the mountains and taken by means of virtually horizontal watercourses, called ‘levadas’ to the agricultural land. By this means some villagers can grow up to 3 crops per year on their terraces or ‘poios’, with crops such as potato, beans, cabbage, maize being grown on the same piece of land. Around one quarter of the island’s total surface of 870 km2 used to be farmed and in the 19th century the state began to build several long levadas to take the water from the mountains on the north side to the fertile east, west and south parts of Madeira, where it was sold to the farmers to irrigate their land.
GEOLOGY Madeira was formed by volcanic eruptions which occurred between 20 million and 1.7 million years ago. Then the mountain building ceased and erosion by sea, rain and ice started. The central massif is very eroded and typical volcanic cones are only seen in a few coastal areas. There are many steep sided ravines which are usually wider at their source (where there is softer volcanic material) and narrow towards the mouth, where harder basalt is generally found. The Levada do Caldeirão Verde runs to the south of the Ribeiro Grande ravine and after 1¾ hours of walking with drops of up to 1650 ft (500m) on your right hand side you come to a spectacular circular amphitheatre festooned with green vegetation and with a fine 1000 foot (300 m) waterfall. This is one of several caldera on the island – circular pits which were the vents from which pyroclastic material was expelled in violent explosive eruptions. Pyroclasts are classified according to the size of the material expelled, from the finest ashes through gritty lapilli to the largest and most solid volcanic bombs. When the volcanic activity ceased, circular vents with sheer-sided walls remained to be colonised by vegetation and eroded by water, ice and snow. The way down to civilization follows an ancient path which is diabolically slippery. This is because the rock underfoot is ‘massapez’ – a very hard ‘rock’ comprising a mixture of volcanic ash and sand. It weathers to a reddish sort of clay which when moist – as it usually is in the lush, cloudy laurel forests – has a surface like a skating rink. You are advised to walk on any vegetation you can when you hit this sort of terrain as moss and grass tends to be less slippy.
VEGETATION Around 15,000 hectares (20%) of Madeira’s surface is covered by Laurissilva forest, mostly between 600 and 1300 metres above sea level where it is very humid and there is frequent fog. It is a natural relic of the sort of forest that abounded in Europe in the past but which succumbed to the low temperatures of the Wurm ice age that came to an end around 12,000 years ago. It consists mostly of laurel trees but also other trees from the same family, especially Barbusano (Canary laurel), Til (Foetid laurel) and Vinhatico (Madeira mahogany). Despite the fact that it covers such a large part of Madeira the places where the forest is best preserved are not easy to access and the Levada do Caldeirão Verde (& the Rabacal levada) are the best options to see this type of forest up close. It is so important that it was created a World Natural Heritage Site by UNESCO in 1999 and is designated as a Biogenetic Reserve by the Council of Europe. Only people with appropriate scientific authorisation may pick, capture or disturb the indigenous species.
CLAIMING THIS EARTHCACHE The steepness of the terrain means you are unlikely to be able to get a GPS signal anywhere near the site. Mine could only pick up one satellite at the waterfall so the listing co-ordinates are only approximate.
However, you can’t really go wrong – there is only one path to the area and it is signposted! Another geocacher placed the waterfall at N 32 46.478 W 16 56.057 but, whatever, you should have no problem finding this Earthcache if you follow the levada.
To log this Earthcache you have to email me with your estimate of the weight (kg or tonnes) of the conspicuous boulder at the southern edge of the pool (left side as you look at the 300 m waterfall)
To do this I suggest you try and work out the circumference in centimetres and assume it is a sphere. (If you use centimetres the calculation is easier but it is still easy to get the order of decimal places wrong.),br/> You can find the radius (r) as your circumference is 2 π r . You can then use the radius and multiply it by 4/3 π r3.
To ‘guesstimate’ the weight you can assume a rock density of 0.0025 kg/cm3.