Hydrogeochemical characterization of river ans shallow alluvial aquifer

Agricultural zones are characterized for using fertilizers and phytosanitary products to optimize the crops' yield, which generates an impact on the quality of the surface and groundwater bodies, as well as on the interactions and relations that exist between them.

Jarama’s river lower course basin, which crosses the Community of Madrid, is characterized as an area of intense agricultural activity, with a combination of different land uses: urban and industrial uses along with aggregates extractions and protected and naturalized areas such as the "Parque Regional del Sureste".

The development of intensive agriculture in this area (known as Vega Baja) focuses on crops such as corn, seasonal crops and fruit and horticultural species, that use irrigation methods with different water demands: flood, sprinkler and drip.  

Agriculture implies a non-consumptive use of water. Once it has been extracted from the environment it is returned, but not to the same location or in the same physical-chemical or biological conditions. When water supply exceeds the needs of the crop and the soil, the surplus of irrigation mobilizes the fertilizers and phytosanitary products not taken by the plant, concentrating in rivers, lakes, reservoirs and aquifers. Therefore, generating losses in the water quality such as eutrophication and pollution.

On the other hand, the water supply and wastewater depuration associated to human activities generates a significant impact derived from the services required by cities and industrial zones. Treated effluents are quite relevant, as they involve a quantitative and qualitative modification of the water resources at the discharge area, which should be assessed and analyzed.

Furthermore, the impacts derived from extractive activities add to this equation, since they modify the flow and dynamic of the water in the aquifer while affecting the groundwater recharge and evaporation rates.

Therefore, within the framework of the Smart-Hydro project, researchers from IMDEA Water have published the article “Hydrogeochemical characterization of a shallow alluvial aquifer: 1 baseline for groundwater quality assessment and resource management”.

This paper presents the results of a 3-year hydrogeochemical water characterization, explains the physical and chemical processes that take place in this section of the Jarama river and the "Aluviales: Jarama-Tajuña" aquifer of the Community from Madrid, while aims to establish a qualitative baseline in order to assess and manage the evolution of this water bodies in the future.