mejia lagoons

Region, province of Islay, area 690.6 hectares, desert ecoregion Sub tropical Pacific

Habitat: Beaches marinas, lagoons, river Tambo, Tambo River mouth, coastal mountain, the beach, the gramadales, cattails and rushes, the salicornial

The Lagunas de Mejía National Sanctuary is located on the Pacific coast of southern Peru, in Arequipa. The main objective of the area is the protection of migratory birds and endemic fauna in danger of extinction, as well as associations of existing flora. The Lagunas de Mejía National Sanctuary has been incorporated in the list of sites specifically for the Ramsar Convention, which protects wetlands of global importance. An area adjacent to the sea, flat relief, vegetation cover in the middle of a desert ecosystem, with major gaps that give life to the place.


The area boasts a number of coastal ecosystems that result from the presence of a great diversity of bird species and vegetation that is habitat for the wildlife refuge. It is one of the few protected areas in Peru which retains a portion of riparian forest, typical of the desert Pacific coast. Also introduced salicornial considered a partnership in the plant-dominated verdolaguilla (Salicornia fruticosa), uncommon in other areas of the country. It is the only habitat in nearly 2000 kms of coastline with optimum environmental conditions for normal development of the populations of resident and migratory birds.


Las Lagunas de Mejía is a protected area that is vulnerable. Have been seriously affected by the works adjacent to rehabilitate agricultural land in the Irrigation Iberia started over 20 years. The project carried out actions of drainage areas adjacent to the sanctuary on an area of approximately 2000 hectares, with a view to integrating agricultural development and livestock, which has affected water supply to the lakes, impacting on the ecosystem and birds both migratory and resident waterfowl. In addition to agriculture, are additional factors that disrupt the integrity of the protected area: livestock, hunting, fishing, extraction of rushes, cattails and other plants, firewood collection, human presence within the area, tourism disordered, availability and water quality, lack of values and institutional problems of the sanctuary.

The Lagunas de Mejía National Sanctuary is located on the Pacific coast of southern Peru, in Arequipa, in the districts Mejia, Dean Valdivia and a small portion of Punta Bombon, a few meters from the tide line of the Ocean Pacific. Its catchment area covers different types of habitats: swamps, saline mud flats, cattails, coastal bush, gramadales vast sandy beaches. This complex of habitats collected in a small area (690.6 hectares), is one of the most important wetlands on the west coast of South America, which also houses a large number of species of resident and migratory birds and other fauna samples, flora and microflora characteristic of wetlands.

Location, extent and limits

The Lagunas de Mejía National Sanctuary is located on the southern coast of Peru, 3 km from the spa Mejia, 19 kms from Mollendo (the largest town in the vicinity). Its location corresponds to the following range of geographical coordinates: 17 ° 07'09 "and 17 ° 10'03" south latitude and 71 ° 49'49 "and 71 ° 53'19" west longitude. The sanctuary is almost at sea level and has a natural dam with a height of 3.40 meters above sea level, which separates the lagoons from the ocean. Throughout the sanctuary is the recorded peak of 3.50 meters above sea level and the minimum height of 0.50 meters above sea level.

According to his decree creating the sanctuary covers an area of 690.6 hectares, which includes the so-called Lagunas de Mejia and adjoining land, and stretches to the south, including the coastal mountain on the left bank of the river Tambo, near its mouth. Bordered to the north by the plant bombs and channel for the disposal of drainage water for irrigation Iberia, to the east of the paved road Mollendo-Tambo Valley Irrigation Iberia-the-Boquerón, to the south by agricultural land Punta de Bombon and the west line of the beach of the Sea.


The area of the sanctuary was part of a large sedimentation basin, which, thanks to various geological events, governed the deposition of marine and continental sediments that belong to the Quaternary. In the sanctuary there are no rocky outcrops.


The sanctuary itself presents the landscape of the flood plains of the Peruvian coast, as well as flat terrain that may include topographic depressions close to the sea. Generally, the topography shows a flooded area more or less uniform, with minimal changes in elevation.


The soils in the protected area have a uniform texture. The surface horizons are sandy and vary slightly below one meters depth. Only in a field near the gaps can be found clay horizons reindeer.

The soils present serious drainage problems in view of various sectors in the water table is very close to ground level (the range of groundwater level ranges from 0.30 to 1.60 meters). In some cases, the water level exceeds the soil and form sheets or temporary bodies of water, especially in the winter season under the influence of tide changes.

The origin of the sanctuary of the soils and the adjacent plains of Iberia is basically alluvial type, with marine influence. Additionally, in the most deprived areas, has some recent lacustrine formation. Consequently, they are sandy and range from open sand (without silt, clay and humus) to free-gritty. Additionally, they have a profile characterized by the presence of hard layers in the subsoil (formed by layers of clay and loamy soils frank with the presence of volcanic ash), plus pumice. These hard, at a depth range of 0.8 - 1.2 meters, restricting drainage and lead to soil salinization.

A large percentage of land in neighboring Irrigation Iberia has serious problems with the groundwater level and quality of soils. The soil (almost 40% of parcels) with depths to 75 cm. where some crops are severely affected. The vast majority of soils have low fertility and high concentrations of salts.


Despite its relative proximity to the equator, the area where the Lagunas de Mejía National Sanctuary has an annual average temperature low. According to the meteorological station nearest (Mollendo), the average annual temperature is 19.8 ° C and the average total annual precipitation is 10.8 mm. This is largely due to the influence of the Peruvian or Humboldt Current, cold-water marine, whose presence also prevents the formation of rain, making this part of the coastal zone is an extremely desert from the department of Ica in Peru to La Serena in Chile. Rainfall in the area are rare, commonly called garua product mists of winter.

The local climate is typical of the dry desert area of life - Warm Temperate desert or hyper - Warm Temperate, characterized by extremely arid. Due to low rainfall or lack thereof, some years are hydrologically dry.

camino sipia


Tambo River Basin has a maximum length of travel of 276 kms from its headwaters in the district of the department of Moquegua Yunga high in the Andes, the product of the confluence of the rivers Ichuña and Paltiture to its mouth at the Pacific Ocean . This basin has an average gradient of 1.4%, which is accentuated in the Upper Tambo River (1.9%) and the river Coralaque (1.9%), its largest tributary. Its total area is 12,454 km ², of which 8149 km ² are wet basin.

The basin of the river are those of the rivers on the coast, long and deep, with steep topography and steep sides, cut by deep gorges. At the top are some gaps, due to a phenomenon of glaciation, while the bottom of the valley presents a product of plain deposits of alluvial origin due to a sharp decrease of the slope.


Bank of the river Tambo

The system downloads the river and streams is irregular, fluctuates over the seasons and vary widely between the months of rain and drought. February is the month of greatest abundance of water, with a monthly average discharge of 106 m³ / sec., And the month of November is the driest since reaching 7-9 m / sec. The rainy season in the highlands of the basin started in December and lasts until April.


On both sides of the mouth of the river Tambo varying needs further and probably different origins. The gaps in the area north of the river mouth, the system of lagoons and Iberia Mejia, are actually outcrops return irrigation water located in the Pampas of Iberia. Water that originates from these gaps and leaks in the surface irrigation flows-Mejia-Mollendo Ensenada, which dates from 1942. Irrigation Iberia (Iberia Pampas) influences the effect of Iberia lagoon seepage and surface runoff. The Tambo River is also an important source of water for the lagoons of Boquerón given that at its peak discharge (December to April) of water flooded the lower Boquerón feeding the gaps there. This is found in the lakes of the southern shrine by the presence of sediment-laden turbid waters. Additionally, it is known that these ponds receive water from the water table in the basin.

The system of gaps in the sanctuary (north, center and south), known as lagoons Mejia, Iberia and Boquerón respectively, with different hydrological regimes, so that alternatives for its management should also be different, defining a common objective: ensuring enough water to bring the ecological function and providing refuge to migratory flows and sedentary birds. Thus, the hydrological behavior of the three ponds is a function of the balance between water supply and the same losses. Estimated losses are divided into losses by percolation into the Pacific Ocean (about 30%), evaporation losses (50-60%) and possibly a minor loss (10-20%) by percolation system of drainage Irrigation Iberia.

Gaps are considered superficial because the average level of the water fluctuates between 80 and 195 cm. deep, with strong seasonal variations. It is estimated that in the case of Iberia lagoon (central), with a level of 145 cm. The area of the lake reaches 40 hectares and with 195 cm. its area increased to 80 hectares. Boquerón gap in the level is between 80 and 160 cm., Obtaining an area of 5 hectares. The lagoon Mejia, meanwhile, has an irregular fluctuation due to any chance that dries completely the effect of the drainage system. Its average level is 100 cm. With which it maintains an area of four hectares.


view of cotahuasi

Water to the lakes

The gaps were affected by the rehabilitation of agricultural land in its area of influence and which unfortunately failed to conduct environmental impact studies. This had serious consequences in these important coastal wetlands, and that during testing in 1981 82 were dried at 80% of its area.

With the intent to remedy this shortcoming, the Government of the Netherlands, which at that time advised that work, he sent a special mission ILAC in 1984, which recommended among other things out of the drainage ponds No. 3, the gaps with feedback water was pumped into the sea, feeding the lagoons with irrigation water from Ensenada, and used and surplus of agricultural activity. Plan REHATIC (rehabilitation of agricultural land), funded by the Government of the Netherlands, met with the drainage out for No. 3 do not directly involve the drainage of the lagoons.

In the system of pumping because of its high cost and low profitability of the plots, the feedback was not likely to be executed, and finally topping with the irrigation water was ruled out by the problems with farmers using groundwater for irrigation and drag much sedimentary material produced a severe acolmatamiento of the gaps.

Based on studies by the Project implemented by PRODENA Ecodesarrollo Arequipa, a system for monitoring the levels of 1 and 3 drains through a gate in order not to let them down too much to the point of affecting the level of gaps, but at the same time as the water table of surrounding plots were not very high, and set the minimum level of retention at 1.50 meters. In addition, the project rehabilitated the former No. 3 Drainage and blocked their exit, and built two other blind drains in the form of "T" to feed gaps indirectly by filtration to prevent clogging by sediment contamination by unwanted vegetation (lentil and water hyacinth) or by residual pesticides and chemical fertilizers.


Due to its geographical location, the Lagunas de Mejía National Sanctuary has no access problems. He can be reached easily through roads that leave from Lima and from major cities of the south. Five Paths of paved road: Lima-Camana-distribution-Mollendo-Mejia (1020 km), Arequipa-Mollendo-Mejia (143 km), Arequipa-Cachendo-Cocachacra-Mejia (149 km), Moquegua, Tacna-Prosecutor Mejía (295 km) and the new coastal road that goes to the Ilo Valley Tambo (approximately 70 km).