http://lattes.cnpq.br/3293234957426500; BRITO, Virgínia da Costa.
Abstract:
On a recurrent water scarcity scenario in the northeastern semi-arid region due to the
characteristic climatic causes of the region, the São Francisco River Integration Project
(PISF) has brought hope to the population that needs these waters. In the State of
Paraíba, through the east axis, the watershed of the Paraíba River receives the waters
of transposition guaranteeing the water supply of the whole stretch of the river, as well
as the four reservoirs of the series - Poções, Camalau, Boqueirão and Acauã – which
are receivers of the project's water flow. The PISF was planned and executed through
the construction of open channels, where the water is transported in direct contact with
the external environment, leading to considerable water losses for the system. Due to
the importance of this system for the region and the concern with its water
management, a question is placed about how this water can be distributed an used
when it reaches the Paraíba river basin in a way that water and financial losses can be
minimized. Thus, the objective of this research is to study the behavior of water losses
in transit along the river and by evaporation in the four reservoirs in series, which are
recipients of the exogenous PISF flow, and calculate the costs of water losses for each
scenario. For this, four scenarios were created taking into account the current form of
transposition and scenarios with a proposal of a new pipeline to the ETA (Water
Treatment Station) of Gravatá, located in the city of Queimadas, in Paraíba,
transporting part of the flow of the integration project. Scenarios with the usual
irrigated perimeters of the study area and also with irrigated area restrictions according
to the ANA / AESA Joint Resolution No. 87 of November 5, 2018, were both
considered. The scenarios were evaluated by means of a multiobjective optimization
model based on Sucessive Linear Programming, created by Santos (2011), for a period
of 6 years (2012 to 2017), which was marked by the strong drought in the region
where the reservoirs reached a critical level of accumulation. The results showed that
the demands of urban supply and irrigation were fully met in all scenarios. The
maximum estimated flow rate for the Acauã-Araçagi integration channel is not
sustainable, since its demand has not been fully met, and it overloads the entire
system, especially the Acauã reservoir. It can be concluded that the scenarios that
propose the transportation of part of the flow through a pipeline, showed greater
efficiency in relation to lower water losses and consequently lower costs, with an
economy in the range of 11.1 to 16.8 million Reais per year. The limitations imposed
on the irrigated perimeters by the Joint Resolution ANA / AESA nº 87, did not bring
success to their objectives of reducing the volume of water consumed, in the
optimization process occurred the opposite, that resulted in greater water losses for the
system, costing a further 3,1 million Reais per year.
