Top 9 Lakes around Seseña

The lower basin of the Jarama River is the river axis that links the main elements of the Regional Park of the Southeast. The rich alluvial plains hide 132 artificial lagoons that are authentic distributors of exclusivity and biological diversity. The origin of these valuable wetlands is the extraction of aggregates in the open air, digging enormous holes until breaking the water table and causing the flooding of the gravel pit with water from the river basin. In a short time, the banks of these particular artificial ponds are covered with rushes, reeds, cattails, tamarisks, willows, ash trees and elms, developing leafy belts of marsh vegetation that constitute a magnificent habitat for different groups of aquatic birds, reptiles and amphibians. The gypsum cliffs are also an indispensable environmental element to delve deeper into the surprising natural wealth of the regional park and enrich the aesthetic quality of the landscape. The striking grey and whitish cliffs, with a fragile and arid appearance, are formed by large layers of marl and gypsum sediments piled up during the Miocene while large masses of water containing abundant mineral salts were evaporating. The steep and desolate appearance of these unique reliefs, together with the toxic nature of a substrate rich in calcium sulphate, conditions the development of the plant species that colonize the unstable cliffs, unique and sometimes endemic plants adapted to the demanding conditions in this exclusive geographical section of the park.

In spring and during the rainy season, the blue surface of the Esteras lagoon is an environmental jewel in the arid landscape of the rural moorland. The volume of water depends on rainfall and evaporation. During long periods of high temperatures, the water disappears and becomes a white salt lake with a noticeable crust of mineral salts. In this case, it is advisable not to enter the lake to closely observe the sodium sulphate crystals because it is a mud trap, the wetland is always under the salt.

At this point on the path of La Blanca, at the height of the San Juan lagoons, there is a viewpoint frequented by bird lovers. It is a perfect point to see the fauna that inhabits this seasonal wetland.

The route enters the Cañada del Raso through the access to a gypsum factory, leaves the facilities on the right and passes through the Laguna Seca or Las Esteras wetland, a valuable lake ecosystem in a natural depression in the land that floods temporarily, creating a hypersaline wetland of great geological, botanical and faunal importance of high environmental value, a small wonder in the páramo landscape.

The route begins with the ascent to the Cerro de Peña Blanca to contemplate the landscape of the San Juan lagoon and the extensive plain of the lower Tajuña. The views are magnificent, with good places to plant the tripod and mount an excellent observatory over the panorama of the wetland, the surroundings of steppe hills and irrigated crops. The Cerro de Peña Blanca is an excellent place to see the unique display of plants adapted to the toxicity of a substrate rich in gypsum, called gypsophilous vegetation by experts, species completely specialized in gypsum marl soils rich in calcium sulfate, such as esparto , the soap, the ontina or artemisa and the striking reseda.

The rain falls more frequently on the high moors of Chinchón and Villaconejos and reaches the wetland by runoff, through the gullies of the gypsum cliffs, or by underground infiltration favored by the structure of the land in the form of stepped terraces. Direct recharge through precipitation in the form of rain is scarce at the bottom of the fertile plain, where the San Juan lagoon sits, but it serves to recover the optimal wetland habitat in a short time and reactivates wildlife in the marsh refuge. Water losses are mainly due to underground seepage and solar evaporation, accentuated in the hot summer months, when most of the birds migrate to other wetlands to seek food and shelter. The resident birds in the Laguna de San Juan Fauna Refuge and the nearby environment of the fertile plain and gypsum cliffs are the western marsh harrier, royal blue eagle, eagle owl, purple swamp, common kestrel, black wheatear, common coot, gray heron, falcon basking, kingfisher, red duck, great crested grebe and little grebe. The wintering bird species in the wetland are the great cormorant, marsh bunting, cattle egret, shoveler, European pochard and tufted duck. And the birds present in the summer season in the lagoon and the surrounding steppe mountains are bee-eaters, little bitterns, sand martins, common reed warblers, great gray warblers and purple herons.

You can find this place in the middle area of the Prince's Gardens, accessing through the Puerta de la Plaza Redonda. It is an artificial lake with three islets where you can see a Greek-style temple with Ionic columns that emulate being made of marble, which was built at the beginning of the 18th century by Juan de Villanueva, who was the architect of the Prado museum building.

Nice bird lookout. Go in the rainy season, if they won't be dry