The catchment area of Peppara dam built across Karamana River to supply drinking water to Thiruvananthapuram city and suburban areas forms the forests of Peppara National Park.
It was declared a sanctuary in 1983 as thanks to the ecological significance of the area.
Located 50kms north east of Thiruvananthapuram city, the sanctuary occupies an area of 53 sq.kms out of which the area of the reservoir is 5.82 sq.kms.
The area also includes the areas of two other sanctuaries, the Palode reserve (24sq.kms) and the Kottoor reserve (29sq.kms).
The terrain of the sanctuary is more or less hilly. Peppara National Park is the natural habitat of tiger, panther, wild dog, elephant, gaur, mouse deer, Nilgiri langur, sambhar, lion tailed macaque, barking deer, wild boar, Malabar squirrel etc.
Birdlife of the sanctuary is also prolific.
The bird species include the water birds like darter, little cormorant, pied king fisher and egrets.
A wide variety of species of snakes including the king cobra and python are also found in this reserve.
The Peppara National Park is also well known for its extensive variety of moth and butterflies.
In addition to the wildlife, 13 tribal settlements are also found in the Peppara National Park.
Three major forest belts characterize the flora of the Peppara National Park.
These are: southern hilltop tropical evergreen forests that occur mostly on the hills with an altitude of above 1000m, west coast semi- evergreen forests that found atop the hills with an altitude of 150 to 1050m and southern moist mixed deciduous forests found in the lower slopes of the hills and cover more than 60% of the area.