OF EXISTING BANK RESERVATIONS OF SOME MAJOR NATURAL STREAMS IN MAHAWELI
H M P B Vidyarathne , D M S H K Ranasinghe and M Panapitiya
University of Sri Jayewardenepura
focused on the existence, extent and a checklist of flora of stream reservations
on two of the major natural streams in the Mahaweli System B area in the
Dry zone of Sri Lanka. The Mahaweli Project is the major irrigation and
settlement scheme in Sri Lanka.
comparing the existing reservations with the amount allocated according
to the relevant legislation at the beginning of the Project, the rate
of degradation of reservations over time was assessed. With the use of
transects which were positioned perpendicular to the streams the floristic
composition of woody perennials ( > 10 cm dbh ) was enumerated. The socio-economic
conditions of the neighboring community were also investigated.
The results of the survey showed that the existing reservations on both
of the streams were far inferior to the amounts prescribed in the relevant
legislation ( e.g. Crown Lands Ordinance etc.).The farmers who had been
settled on either side of the streams had gradually encroached on the
reservations especially for paddy cultivation. Other perennial crops like
coconut, mango, jak and breadfruit had also been planted as the water
level was higher near the streams. In both streams the right side was
more encroached than the left side as more farmers were settled on the
There was very little natural vegetation left on the banks. This was partly
due to encroachment and partly due to the widening of the streams intermittently
to cope with the discharge water in the rainy season. In the floristic
survey on streams banks 249 woody individuals (> 10 cm dbh ) were sampled
in Menik Ela while 158 individuals were sampled in the Mahaulpotha Ela.
The total number of plant species encountered was 32 in the Menik Ela
while it was 27 in the Mahaulpotha Ela. The total number of endemics sampled
as a proportion of the total number of tree species sampled was 0.09%
in the former and 0.11% in the latter. The flora varied from typical dry
zone species to wet zone species depending on the bank, soil type and
soil moisture content.
The socio-economic survey revealed that the community in the neighbourhood
of these streams, who had mostly been settled in these areas from other
parts of the country, had a relatively low income, low education and high
birth rate. The majority of them were farmers.
As the existing situation regarding reservations is not at all adequate,
strict legislation against the encroachment on reservations, planting
the encroached land with suitable plant species, possibly with the participation
of the farmers, and strengthening the extension programs to make people
aware of the environmental benefits of conservation were recommended.
Department of Forestry and Environmental Science,
of Sri Jayewardenepura,Sri Lanka. 1999. All rights reserved.