IMPACTS ASSESSMENT ON THE WATER RESOURCES OF THE EL MOLINO RIVER MICROWATERSHED: POTENTIAL RECHARGE, LAND USE, URBAN POLLUTION, SUPPLY AND WATER QUALITY PERCEPTION

Abstract

Introduction: The El Molino River micro-basin in the department of Santa Ana, El Salvador, suffers from water resource pollution, according to previous studies and field observations. Although potentially polluting sources and activities have been identified, the lack of an official inventory of these sources exacerbates the situation. Objective: The objective of this research was to determine the impact of urbanization and agriculture on the potential recharge of the El Molino River micro-basin in Santa Ana, El Salvador, until the year 2023. To this end, the potential water recharge was determined using Schosinsky's methodology. an analysis of land use was carried out using geographic information systems and field reconnaissance; interviews were also conducted with residents living around the El Molino River to learn about their perceptions of water resources; in addition, hydraulic tests were performed on various soil types and a detailed inventory of recognized potential sources of pollution was compiled. Method: A calculation of the potential aquifer recharge is carried out using a method based on soil water balance, proposed by Schosinsky (2006). This process is performed using a spreadsheet called BHS_Schosinsky and was applied to the El Molino River micro-basin. Several fundamental parameters are considered for this calculation, including land use, root depth, infiltration rate, terrain slope range, soil texture, and precipitation and evapotranspiration data from nearby rain gauge stations. Results: Fourteen potential point sources of pollution were identified, as well as large areas where there are potential sources of diffuse pollution.  Conclusion: It was concluded that there is a certain population that is adversely affected in terms of water supply and quality. Urban waste was identified as the main source of water resource pollution, as were the agrochemicals used in coffee cultivation in the area identified as the largest recharge zone of the micro-watershed.