Samadi-Darafshani, M., Safavi, H.R., Golmohammadi, M.H. and Rezaei, F., (2021) Assessment of the management scenarios for groundwater quality remediation of a nitrate-contaminated aquifer. Environmental Monitoring and Assessment, 193(4), pp.1-16.

Assessment of the management scenarios for groundwater quality remediation of a nitrate‑contaminated aquifer

Mahsa Samadi‑Darafshani, Hamid R. Safavi, Mohammad H. Golmohammadi, Farshad Rezaei

Abstract

Nitrate contaminant degrades groundwater quality and threatens the health of the humans, livestock, and the environment. Damaneh-Daran aquifer is located at upstream of the Zayandehrood reservoir in west-central Iran. This aquifer has been highly contaminated by nitrate and is still rapidly being contaminated. Thus, its quality needs to be remediated. This paper is focused on the quantity-quality modeling to predict the average nitrate concentration of the aquifer. Several remediation scenarios are presented in a period beginning from fall 2019, ending in spring 2024. These scenarios address several ways to mitigate the injection of the major sources of contamination in the region, such as equipping the urban regions with wastewater collection and treatment plants and reducing the fertilizers’ use. The decreased use of the fertilizers may be achieved through two strategies: directly reducing the amount of the fertilizers by several specific and predefined rates of reduction and indirectly decreasing the amount of the fertilizers used by crop pattern modification. The latter strategy is evaluated to replace all or a part of the areas allocated to the more fertilizer-demanding crops with those of the less fertilizer-demanding crops. Furthermore, some of these scenarios are hybridized to more mitigate groundwater quality degradation. The results of performing the proposed scenarios are once compared together and then compared with the trend scenario letting current case study conditions and facilities be held in the future. The results suggest that the scenario hybridizing the effects of the wastewater treatment plants-equipping scenario with those of the quality-enhancing crop pattern modification scenario is evaluated as the most effective and best-performing scenario, implementation of which offers 20% and 30% reduction of the nitrate concentration for the agricultural and urban areas, respectively.

Keywords

Groundwater remediation, Water quality, Quantity-quality modeling, MODFLOW, MT3D, Nitrate pollution.