Author(s): M. E Novo; M. M Oliveira; L. Oliveira; T Martins
Linked Author(s): Luiz Eduardo Domingos de Oliveira
Keywords: Climate change; GDEs; Pollution loads
Abstract: A methodology was developed under PROWATERMAN project which uses emissions scenarios (IS92a, SRES A2 and SRES B2) to predict the evolution of aquifer recharge, runoff, lagoon water volume and pollution loads reaching surface and groundwater masses an its final reservoir–Melides lagoon (a groundwater partially dependent ecosystem) –in Melides watershed, in 2100, under emissions scenarios IS92a, SRES A2 and SRES B2, using BALSEQ daily water balance and a methodology developed by Oliveira et al. (2012) to generate the hydrological data required by this model. Results show a recharge reduction from 26% (IS92a scenario) to 60% (SRES A2) and runoff reduction from 10% to 43% for the same scenarios. Assuming only runoff reductions, there would be a water volume reduction in Melides lagoon from today’s 1, 5 hm 3 to 0, 86 hm 3 in SRES A2 and water column height from 3 m (today’s average) to 2, 05 m (today’s average dry year). Runoff will also be more concentrated (IS92a scenario) in winter, which will be translated into longer low to no-flow periods in river network, promoting a wider variation of pollution loads reaching the lagoon, with impacts on ecosystems functioning. Using both the new pollution loads and the new lagoon’s average annual volume and scenarios of groundwater to surface water pollution transfers, projections of pollution evolution in the lagoon were obtained for each emissions scenario. Water exploitation rates were also predicted, assuming changes in water requirements for humans, plants and livestock, based on data in the available literature, and, for farming, the same scenarios above referred were used. The results point to higher water exploitation rates in2100, with the exception of scenario IS92a and reduction of farming areas, which might surpass100% in the most adverse scenario (A2 emissions scenario and farming areas equal to those of2030). It is predicted an increase in pollution load (NO 3) reaching the lagoon due mainly to pollution already travelling along the aquifer, for IS92a; for SRES A2 there will be significant a reduction, once it was assumed no groundwater discharge into the lagoon.
Year: 2014