On the Puttalam Road approximately 100km north of Colombo (15km north of Chilaw), an unsigned left turn 300 metres beyond of the 91km post leads 1.5km down a quiet lane into the heart of another unique wetland region. Annaiwilundawa is a cluster of shallow, 12th-century, manmade, cascading freshwater reservoirs surrounded by and sustaining lowland agriculture. Each tank is 12-50 hectares in size and less than four metres deep, but they collectively help to irrigate more than 400 hectares of traditional paddy and are safe haven to a startling wetland biodiversity.

 
In fact, a 1996 Wetland Conservation Project report gave Annaiwilundawa particularly high biodiversity scores, especially for endemic and threatened species, particularly birds. IUCN statistics from 2000 recorded that 10% of the vertebrate species and several plants identified at Annaiwilundawa are nationally threatened, and the total number of vertebrate fauna species documented amounts to 35-40% of those occurring in Sri Lanka.
 

Situated along a western migratory route for wintering birds, the wetlands are also a vital food and rest stop for tired feathered travellers. These fowl add colour to the resident species, dominated by waterbirds, some of which have settled in large breeding colonies. A total of more than 130 bird species have been recorded, including rare species once thought extinct in Sri Lanka. Lastly, identified in the wetland waters are approximately 50% of the freshwater fish species known in the country, including several endemics, along with migratory fish and an array of the zooplankton and phytoplankton they eat. All of this helped earn Annaiwilundawa recognition as Sri Lanka’s second Ramsar (The Convention on Wetlands) site in August 2001.
 
(Content Source: Travel Sri Lanka Magazine)
(Image Source: sunchare.blogspot.com)