Agriculture Reference
In-Depth Information
regime of the hydropower plant that are necessary in order to maximise the
joint
agriculture-hydropower
profit.
The
resolution
of
this
problem
determines
certain
levels
of reservoir-stored
water
in both periods,
various changes in hydropower allotments and,
of course,
changes in
profits for both users.
In order to make the theoretical model operative, a specific profit
function is constructed such that corresponds to profit per hectare,
i.e.,
the net margin minus other indirect costs, as these are defined in
agricultural accounting (
e.g.
MOPTMA, 1993). As we can see, we assume
linear technology. Furthermore, is determined as 8 pesetas/Kwh, the
restated value of the margin for hydropower production that appears in the
same document. The head is estimated through a function calibrated for the
real data of the Vadiello reservoir, with being the
average reserves in each period. The best fit of the head of the reservoir
and the reserves is obtained through a logarithmic function with coefficient
8.2323. Finally,
is the conversion independent of the released flow and
head in energy
In system 1, there are 1400 hectares of irrigated area, distributed
between four types of crops: cereals, 55%; industrial crops, 29%;
vegetables, 15%; and fruit, 1%. In all cases, we assume an irrigation
efficiency of 47% (see Bielsa, 1999). In system 2, the number of hectares
under irrigation is 700, whilst the distribution of the crops and the
irrigation efficiency is assumed to have the same structure as in system 1.
Both cases, and their associated reallocations, are described in the
following sub-sections.
3.3 Case 1: Reallocation in response to drought
The problem here takes the form of a reduction in the upstream flows of
30%,
i.e.,
a 'typical' dry year
4
. Table 11.1 shows the earlier mentioned
changes in the operational regime that are necessary in order to maximise
the joint agriculture-hydropower profit, as well as the consequences of
these changes in terms of reserves time distribution This table
contains three blocks for each system: the starting point, the case of
drought for current water rights and the distribution of water rights
resulting from the maximisation of the joint profit for this new situation
(optimum solution).
Under the assumption of current rights, and following its order of
priority, deficits appear in the second period of the dry year. For the
hydropower use of system 2, these deficits take the form of the difference
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