Lake Lanao

Lake Lanao is a very big lake.

It sits in the Philippines. It is one of the oldest lakes in the world.

Many people live near the water. They call themselves the Maranao. Their name means "the people living around the lake."

The lake is very deep. Four rivers flow into the water. One river flows out of the lake.

There are four small islands in the water. Many kinds of fish live there too. Some fish are very rare.

People use the water to make power. This helps give light to many homes.

Lake Lanao is a large, ancient lake.

It sits in the province of Lanao del Sur. This is in the Philippines. It is the largest lake in Mindanao. It is also the second largest lake in the whole country. It is one of 15 ancient lakes in the world.

The Maranao people live around the lake. Their name means "the people living around the lake." They have many myths about the water. One story says a great hole formed in the earth. This hole filled with water to make the lake.

Four rivers flow into the lake. These are the Ramain, Taraka, Gata, and Masiu rivers. Only one river flows out. This is the Agus River. This river helps make power for many homes. Power plants use the water to make electricity.

The lake is very deep. It can be very deep in the south. There are four islands in the water. Many kinds of fish live in the lake. Some of these fish are found nowhere else. Sadly, many of these fish are now gone. This happened because of pollution and overfishing.

Lake Lanao is a huge and ancient lake in the Philippines. It sits in the province of Lanao del Sur. This lake is the largest one in Mindanao. It is also the second largest lake in the whole country. Scientists say it is one of only 15 ancient lakes in the world.

The people who live near the water call themselves the Maranao. This name means "the people living around the lake." They have many wonderful myths about how the water arrived.

The lake was formed in a very special way. It was made when a volcano collapsed. A basin was also formed between two mountain ranges. This created a deep place for water to gather. Four rivers flow into the lake. These are the Ramain, Taraka, Gata, and Masiu rivers. The lake is shallowest in the north. It gets much deeper as you move toward the south. There are also four islands in the lake. These are Balutmaito, Balutmasla, Nusa, and Salungan islands.

Many people use the lake to create power. The Agus River is the only river that flows out of the lake. It flows northwest into Iligan Bay. This river travels through two channels. One channel goes over the Maria Cristina Falls. The other goes over the Tinago Falls. Because the lake is 700 meters high, it has great potential for electricity. In 1950, the National Power Corporation began building plants called Agus I through Agus VII. These plants provide 70% of the electricity used in Mindanao.

The history of the lake has seen some hard times. In 1965, the lake was briefly renamed Lake Sultan Alonto. Later, a dam called Agus I was built near Marawi City. This dam turned the lake into a reservoir. This change upset the Maranao people. In 1990, they held a public protest. This led to the Save Lake Lanao Movement, or SALAM. They wanted to protect the lake from big changes. The government eventually created a group to help protect the lake watershed.

Nature in the lake has changed over the years. The lake used to be home to 17 special types of fish. These fish were called endemic species. This means they lived nowhere else on Earth. Sadly, many of these fish are now gone. Scientists believe overfishing and pollution caused this. They also found algae in the water in 2006. This was caused by soil erosion from logging and farming. People still work hard today to protect the lake and its living things.

Lake Lanao is a massive, ancient body of water in the Philippines. It is located in the province of Lanao del Sur. This lake is the largest in the Mindanao region. It is also the second largest lake in the entire country. Scientists consider it one of only 15 ancient lakes in the world.

The local people call themselves the Maranao. This name means "the people living around the lake." They have a deep connection to this water through their history and their culture.

The lake formed through a complex geological process. It was created by tectonic-volcanic damming of a basin. This basin sits between two mountain ranges. The process also involved the collapse of a large volcano. The lake has a maximum depth and a mean depth that varies by location. It is shallowest in the north. It becomes progressively deeper as you move toward the south. Four rivers feed the lake: the Ramain, Taraka, Gata, and Masiu. The only outlet is the Agus River. This river flows northwest into Iligan Bay. It travels through two channels, including the Maria Cristina Falls and the Tinago Falls.

Lake Lanao is vital for producing electricity in the region. The lake sits at an elevation of 700 meters. This height provides great hydroelectric potential. In 1950, the National Power Corporation (NAPOCOR) began building a series of plants. These are known as Agus I through Agus VII. They are located along the Agus River system. These plants generate 70% of the electricity used by people in Mindanao. In 1978, the Marawi Lake Regulation Dam (MLRD) was built at the mouth of the Agus. This allowed five power plants to be commissioned shortly after.

The construction of these plants changed how the lake functions. While the MLRD does not affect downstream dams, the Agus I plant is different. It is located directly on the shoreline in Marawi City. This plant effectively turned the lake into a reservoir. This change caused significant backlash among the Maranao people. In October 1990, they held public demonstrations. This led to the birth of the Save Lake Lanao Movement (SALAM). SALAM wanted to stop NAPOCOR from finishing the Agus I plant. They argued the dam would act as an unnatural outlet. They feared it would cause the lake level to fluctuate by 9 meters.

Conflict between SALAM and NAPOCOR led to government intervention. Aquilino Pimentel Jr. created the Task Force on Agus 1. This group delayed the start of the plant until January 14, 1992. Following this, President Corazon Aquino declared the watershed a reservation. She established the Lake Lanao Watershed Protection and Development Council (LLWPDC). This group included representatives from both SALAM and NAPOCOR. Despite these steps, NAPOCOR has not made major concessions to the Maranao. The Maranao continue to work to protect the watershed from environmental damage.

The lake's biodiversity has faced serious challenges. It was once home to 17 endemic species of cyprinid fish. Endemic means these species live nowhere else. These fish belong to the genus Barbodes. They likely evolved quickly from the common barb, Barbodes binotatus. They may have migrated from Sundaland and changed over 10,000 to 20,000 years. However, many of these species are now in danger. In 2020, 15 of the endemic species were regarded as extinct. Two others, B. lindog and B. sirang, are possibly extinct. Overfishing, pollution, and competition from introduced species caused this decline.

Environmental issues also affect the water quality. In October 2006, a study found massive algae contamination. At first, people thought sewage or agricultural waste caused it. However, the Department of Agriculture found a different cause. They stated that soil erosion caused the problem. This erosion comes from extensive farming and indiscriminate logging. The lake also supports a large population of waterfowl. A freshwater crab called Sundathelphusa wolterecki is also endemic to this region. Protecting the lake remains a major concern for the local community.