Sociohydrological diagnosis of three urban wetlands in Xalapa, Ver., Mexico

Abstract

Water is one of the most important components of wetlands. Within the urban and peri-urban area there are wetlands that are generally disturbed by the growth of cities. The objectives of this research were to carry out a physicochemical and biological diagnosis of the water in three urban wetlands in the City of Xalapa, Ver., Mexico, and investigate the effect of hydrological changes in wetlands on the quality of life of the inhabitants surrounding such ecosystems. The water level was measured monthly and the concentration of nitrates (NO₃^-), nitrites (NO₂^- ) phosphates (P0₄^-3), and sulfates (SO₄^-2) were analyzed, as well as the concentration of total and fecal coliform bacteria in water at different points in the three wetlands from June to November 2021. The inhabitants near the wetlands were given a semi-structured interview to investigate how the hydrological changes in the wetlands affect their quality of life. It was found that the three wetlands presented a water column of 10 to 80 cm, with a variation according to rainfall. The Molinos de San Roque wetland presents a fragmentation of the ecosystem due to the construction of a deep channel, which has caused an important area with low flooding. The concentration of anions reflected eutrophic conditions in the three wetlands and the concentration of total and fecal coliforms was higher than 20000 colonies/100 mL August for the three wetlands indicating a sewage contamination. It was found that only the settlements surrounding the Molinos de San Roque wetland were flooded. This wetland also showed the highest hydrological changes. It was found that 44% of the interviewees suffer flooding in their houses in the rainy season (April to November). 25% of the interviewees mentioned economic losses and 47% had health problems due to the floods. 79% of them do not know what a wetland is and, therefore, are unaware that these ecosystems can mitigate floods. Some of the inhabitants interviewed identify marine and coastal wetlands but 95% of the study sample does not recognize an urban wetland. It is concluded that the rehabilitation strategy of these urban wetlands must consider the use of 'constructed' wetlands for cleaning the urban runoff that enters them and that the water that floods the surrounding neighborhoods to the Molinos de San Roque wetland should be channeled to these constructed wetlands.