Verspreiding inlaatwater in beeld met nieuwe tracer

Inlaatwater heeft in de polder Quarles van Ufford zelfs in een droge periode geen invloed op de waterkwaliteit van kleine landbouwsloten. Dat blijkt uit metingen van de concentratie gadolinium, die zijn uitgevoerd voor het project Monitoring Stroomgebieden. Hiermee komt voor dit gebied een einde aan de twijfel over de invloed van inlaatwater op de oppervlaktewaterkwaliteit en is er meer duidelijkheid over de belasting vanuit de landbouw

Tracing the spatial propagation of river inlet water into an agricultural polder area using anthropogenic gadolinium

Diverting river water into agricultural areas or nature reserves is a frequently applied management strategy to prevent fresh water shortage. However, the river water might have negative consequences for chemical and ecological water quality in the receiving water bodies. This study aimed to obtain a spatial image of the diverted river water propagation into a hydrologically complex polder area, the polder Quarles van Ufford in The Netherlands. We used anthropogenic gadolinium (Gd-anomaly) as a tracer for river water that was diverted into the polder. A clear reduction in the river water contribution was found between very dry conditions on 5 August 2010 and very wet conditions on 22 October. Despite the large river water impact on 5 August, the diverted river water did not propagate up into the small agricultural headwater ditches. Gadolinium proved to be an effective tracer for diverted river water in a polder system. We applied our results to upgrade the interpretation of water quality monitoring data and to validate an integrated nutrient transport mode