RANASINGHE, V.S.K.2021-03-292021-03-292013UWU/AQT/09/0038http://www.erepo.lib.uwu.ac.lk/bitstream/handle/123456789/6279/UWULD%20AQT%2009%200038-08052019105919.pdf?sequence=1&isAllowed=yColombo- Katunayake express way is running through part of the Negombo lagoon called Madabokka. Therefore water circulation of that part is not functioning well. It affects to the biological habitat such as benthic fauna and flora of the lagoon. The aim of this research was to study the present benthic diversity and the sea grass biomass distribution of this part of the lagoon. Sampling was conducted in 16 sites of sie selected trasects in the affected area. Water samples and benthic samples were collected in each study site. Benthic samples were analysed to identify and quantify benthic fauna, pH, salinity, P034- and NO3- were measured. These results were compared with data obtain prior to the construction of Colombo¬Katunayake Express way using mini tab 14 software. According to the results there was a significant difference between prior and after data obtained. Four transect out the 6 showed the significant difference. Other two locations also affected by the express way, did not show the difference because one is situated near to the some kind of inlet and the other location is open to the water current which coming from the Katunaya area. It is concluded that the benthic habitats of the lagoon area called Madabokka heavily affected with the CKE.enAquatic Resources Technology Degree Programme ( AQT)Thesis