An attempt has been made to develop a hydrologic and nutrient budget
for Achankovil river watershed (area 1484 km
$^2$
) in Western
Ghats of India. The work was carried out in the year 2002 during three seasons
i.e. pre-monsoon (February), monsoon (June/July) and post-monsoon (October).
The water budget was determined using the formulae dm/dt = Σ input
− Σ outputs + Σ (sources − sinks). The inflow
(precipitation, tributary and Achankovil river baseflow) and out-flow
(evapo-transpiration and discharge from tributaries and Achankovil river)
segments were measured following the standard procedure for three seasons. The
result indicates that significant amount of water leaving (60.35 ×
10
$^8$
m
$^3$
) the watershed to the adjoining
Vembanad lake and ultimately into the ocean, which exceeds the water, entering
(54.83 × 10
$^8$
m
$^3) the basin. The outgoing
water (≅9%) surplus may be due to overestimation of transpiration and the
lack of estimation of the water input from the intermittent streams in the
present study. Nitrogen and phosphorus balances are also calculated by
LOICZ-CABARET budget model. 20,976.86 × 10<FORMULA>^6$
m mol/yr
and 19,655.1 × 10
$^6$
m mol/yr of nitrogen and
phosphorus were lost or utilized within the Achankovil river basin during the
study period. More detailed study on short term and variation will certainly
help us in dealing with the various sources and the contribution by main stream
as well as intermittent streams.
