Modelling phosphorus inputs and dynamics in a large tropical semiarid basin
Abstract
This
study
proposed
a
simple
process-based
model
to
predict
total
phosphorus
(TP)
inputs
and
dynamics
in
large
tropical
semiarid
basin
Brazil
(19,015
km²),
where
the
Castanhão
dam,
largest
non-hydropower
reservoir
Latin
America,
is
located.
The
solved
on
monthly
basis
water
balance
TP
along
river
system,
considering
complete
mixing
at
cross-section,
steady-state
regime
piston-type
transport
with
first-order
decay.
Both
primary
secondary
data
were
used
validate
model,
deviations
of
up
about
20%.
A
linear
increase
flow
rate
was
observed,
indicating
that
transmission
gains
dominant.
concentration
increased
consistent
decay
system
observed.
from
point-sources
(PS)
assumed
constant.
non-point
sources
(NPS)
decreased
time
(R²
=
0.90)
due
continuous
wash-off
process.
NPS
dominant
load,
decreasing
respectively
99
61%
load
high
low
flows.
varied
1-141
ton/month,
an
average
34
ton/month.
resulted
yield
21.2
kg
km-2
year-1,
which
significantly
lower
than
national
peculiarities
region:
precipitation,
intermittent
rivers
high-density
network.
All
simulated
values
above
mandatory
limit
0.05
mg/L.
PS
reduction
only
effective
for
relatively
flows,
while
most
relevant
remediation
measure
both
impact
climate
change
also
yielded
>
mg/L
all
projected
scenarios,
input
loads
spanning
23
266
can
be
applied
other
regions
different
hydroclimatic
conditions
land
uses.
Research Square (Research Square), Год журнала: 2024, Номер unknown
Опубликована: Ноя. 19, 2024
Язык: Английский
