Cambodia is an amazing country located in the southwest part of the Indochina peninsula and covers area of about 181,035 square kilometers of which around twenty percent is used in agriculture. The area lies in the tropical region and its capital is Phnom Penh.
The International borders of Cambodia are shared by several countries like in the North there is Thailand, in the west there is Laos, Vietnam on the East and Gulf of Thailand in the Southeast. Unlike its neighbors, Cambodia is a geographically connected country that has been divided by administration into 20 provinces, 2 municipalities, 172 districts and 1547 communities. Cambodia has a coastline of about 435 km along with elaborate mangrove forests that are still untouched.
Most prominent features in Cambodian Landscape are the water systems like the Great Lake Tonle Sap, the Bassac river system and the Mekong River that flows across the country from the North to the South. Around the central plains in Cambodia, which are about three quarters of the entire country are the dense forests and meagerly populated highlands which comprise of The Elephant Mountains, The Cardamom Mountains, The Dangrek Mountains, The Rattnakiri plateau and the Chhlong Highlands located in different directions. While the Dangrek Mountains are located adjoining to the Korat plateau of Thailand, the Chhlong Highlands merge into the Central highlands of Vietnam. The basin of the Tonle Sap lowlands has plains with elevations not more than 100 meters high.
With the increase in the elevation, the terrain becomes more plunging and divided. The Cardamom Mountains situated in the southwest regions elevate up to 1500 meters and slant towards the northwest and southwest direction. Phnom Aural is the highest mountain in Cambodia and is around 1771 meters high and is situated in the Eastern region of the terrain.
The Elephant Range is an extension of the Cardamom Mountains and runs towards the South and Southeast, rising to an elevation ranging between 500 to 1000 meters. The two ranges share borders with the Narrow coastal plains, facing the Gulf of Thailand containing Kampong Som Bay. The Dangrek Mountains are situated on the Northern edge of the basin of Tonle Sap and a steep ridge is situated on the rim of the Korat Plateau of Thailand which acts as a boundary between Thailand and Cambodia. The average elevation of the Dangrek Mountains is about 500 meters while the highest peak is more than 700 meters. Situated between the Northern Cardamom Ranges and Western Dangrek range is the extension of the Tonle Sap Basin that meanders into the plains of Thailand, creating an easy approach from the Bangkok border.
Cambodia’s largest river is the Mekong River, which controls the basic hydrology of the place. This River sources from the Mainland China and reaches Cambodia through Myanmar, Laos and Thailand. The Bassak river from the South, Tonle Sap River from the northwest meet the Great lake of Tonle Sap in the capital city Phnom Penh and flow southeastward towards the lower delta situated in the Vietnam and later merges into the South China sea.
The part of the Mekong River that passes through Cambodia is situated between the tropical wet and dry regions and there is a dry season when the northern hemisphere faces winters and there is around 80 percent of annual rainfall between May to October. The flow of the Mekong River on an average annually at Kratie of 441km3 is around 93 percent that discharges into the sea. The discharge ranges from minimum 1250m3/s to maximum 66700m3/s. Mekong river is a huge one that flows through the country and is a major source of water.
The Tonle Sap acts as a barrier to the floods from the Mekong River and due to this river the beneficial dry season helps in acting as a shield. During the monsoon season the Mekong River swells with water and flood discharge reaches 40000m3/s at Phnom Penh. During the mid-June the monsoon rains fill the Mekong and Bassak rivers to the flood point and the delta is full of huge volumes of water, which can flood the entire plains for around four to seven months. However, the floodwater does not overflow during this time, but enter the Tonle Sap River, which is 120 km long and directs towards the Great Lake which is the largest natural lake in the Southeast Asia. The size of the lake increases from 2600 km2 to 10,000-13000km2 and the level rises by 7 meters during the times of floods. This is a specialty of the Tonle Sap River due to which it is the only river in the world with a return. When the water swelling in the Mekong river increases and the channels are no more able to handle the volume of water, the flow reverses instead of flowing out and reaches the inflated lake. The Great Lake acts like a natural basin that halts the flooding in the region. Once the floods diminish, the water starts flowing out of the Great Lake and reaches the maximum outflow rate of 2m/s during the dry season and increases the flow of the mainstream by 16 percent. This helps in reducing the saline disturbance in the lower Mekong Delta that is located in Vietnam. When the level of the Great Lake drops to its minimum level, around 20-30 km wide stretch has inundated forests which is dry and has fresh deposits of sediment soil. This forest is great for fishing, but is now reduced to a great extent due to salvation and deforestation. The flood area which is around Phnom Penh up to the Vietnam border is around 7000km2.