Author(s): Wilian Salazar Coronel; Javier Paredes; Lia Ramos

Linked Author(s):

Keywords: Hydrological alteration; Ecological flow; AQUATOOL - SIMGES; Lurin

Abstract: Today, the definition and harmonization with the rest of the uses of ecological flows is being one of the greatest challenges of hydrological planning. In the present study, this problem is addressed in the Lurin river basin (Peru). This river is characterized by being torrential in the humid months and with minimal flows in the dry season. In order to propose a comprehensive and sustainable management of the system, a series of studies were carried out. In the first place, the ecological flow was calculated by four hydrological methods, highlighting the method according to Peruvian legislation, in the middle zone (Antapucro) and in the Lurin intake. The second task consisted of carrying out a water balance of the basin using a management simulation model. For this, the SIMGES program of the AQUATOOL decision support system was used. With this model, the degree of satisfaction of supply of the demands was calculated, as well as the circulating flows through the river sections for the current situation and four proposals: implementation of ecological flows (i); reuse of treated water to supply agricultural demands (ii); construction of a reservoir (40 hm3/year) (iii) and integrate the reuse of reclaimed water with the construction of the reservoir (iv). Finally, the simulation results are combined with the calculation of hydrological alteration indices, which allow the estimation of the degree of hydrological alteration. The ecological flow obtained in Antapucro varies from 20,678 to 40,251 hm3/year. The population, livestock, industrial and recreational demand has a 100% satisfaction due to the source of water from the Lurin aquifer, but not the agricultural demand that is supplied by surface waters. Thus, with the implementation of the ecological flow, agricultural demand increases its deficit by 14.3% compared to the current situation, requiring the use of approximately 30 hm3/year of reclaimed water and the construction of the reservoir. The Lurin aquifer is hydraulically connected to the river, supplying 24,235 hm3 / year to all demands, this reaches a sustainable use with the implementation of the proposal iv. The hydrological alteration indices (AHI) show a good state of the river with a value of 0.78 in the current situation, since the river discharges most of the flow in the wet months (January, February, and March). But the indices that evaluate droughts have low values, due to the fact that in times of dryness the flows are minimal. The global IAH values obtained for proposals i, ii, iii and iv were 0.83, 0.80, 0.69, 0.70, as expected in the last two proposals the value is lower due to the construction of the reservoir.

DOI: https://doi.org/10.3850/IAHR-39WC2521711920221541

Year: 2022