Terrain & Geomorphology

The sanctuary lies in between the Anamalai hills and Nelliampathy hills. Much of the sanctuary is part of Anamalai hills with peaks up to 1,438m (Karimala Gopuram) in the southern boundary of the sanctuary, 1,120m (Vengoli malai) in the eastern boundary, 1,010m (Puliyarapadam) in the west and 1,290m (Pandaravarai peak) in the north.

Nelliampathy hills that lies in the north scale down and opens up itself at a place called Thoothampara, just abutting the northern boundary of the sanctuary which provides a natural opening through the Nelliampathy hills from Anamalai hills, at an average elevation of 600m above mean sea level. From the south western perspective, where, Parambikulam Ar and Sholai Ar meet at a point where the elevation is 473m (the second lowest point in the sanctuary), to form Chalakkudy river, the sanctuary appears as a completely tilted drainage basin that drains to this point, except for a little portion in the north, where the drainage is towards east.

Climate & Rain fall

Temperature in the sanctuary is 15.30˚C. Absolute extreme range of temperature in the sanctuary is 32.8˚C. However, March is the hottest month with mean monthly temperature of 25.74˚C and January the coolest month with 21.2˚C. Temperature condition prevailing in the sanctuary is influenced by normal lapse rate due to which every 100m of ascent from MSL will experience a fall of 0.65˚C in temperature.

Though the sanctuary is blessed with rain during both North West monsoon and North East monsoon, the former contributes maximum to the total precipitation recorded in the sanctuary. In addition, pre monsoon showers are felt during April and May.

Rivers

Karappara, Kuriarkutty