Urban hydrogeology: Transport routes and mixing of water and solutes in a groundwater influenced urban lowland catchment

Liang Yu; Joachim C Rozemeijer; Ype van der Velde; Boris M van Breukelen; Maarten Ouboter; Hans Peter Broers

doi:10.1016/j.scitotenv.2019.04.428

Urban hydrogeology: Transport routes and mixing of water and solutes in a groundwater influenced urban lowland catchment

Sci Total Environ. 2019 Aug 15:678:288-300. doi: 10.1016/j.scitotenv.2019.04.428. Epub 2019 Apr 29.

Authors

Liang Yu¹, Joachim C Rozemeijer², Ype van der Velde³, Boris M van Breukelen⁴, Maarten Ouboter⁵, Hans Peter Broers⁶

Affiliations

¹ Faculty of Science, Vrije University Amsterdam, Amsterdam 1181HV, the Netherlands; Waternet Water Authority, Amsterdam 1096 AC, the Netherlands; TNO Geological Survey of the Netherlands, Utrecht 3584 CB, the Netherlands. Electronic address: l.yu@vu.nl.
² Deltares, Utrecht 3508 TC, the Netherlands.
³ Faculty of Science, Vrije University Amsterdam, Amsterdam 1181HV, the Netherlands.
⁴ Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, Stevinweg 1, 2628 CN Delft, the Netherlands.
⁵ Waternet Water Authority, Amsterdam 1096 AC, the Netherlands.
⁶ TNO Geological Survey of the Netherlands, Utrecht 3584 CB, the Netherlands.

PMID: 31075595
DOI: 10.1016/j.scitotenv.2019.04.428

Abstract

Urban areas in coastal lowlands host a significant part of the world's population. In these areas, cities have often expanded to unfavorable locations that have to be drained or where excess rain water and groundwater need to be pumped away in order to maintain dry feet for its citizens. As a result, groundwater seepage influences surface water quality in many of such urban lowland catchments. This study aims at identifying the flow routes and mixing processes that control surface water quality in the groundwater-influenced urban catchment Polder Geuzenveld, which is part of the city of Amsterdam. Geuzenveld is a highly paved urban area with a subsurface rain water collection system, a groundwater drainage system, and a main surface water system that receive runoff from pavement and roofs, shallow groundwater and direct groundwater seepage, respectively. We conducted a field survey and systematic monitoring to identify the spatial and temporal variations in water quality in runoff, ditch water, drain water, and shallow and deep groundwater. We found that Geuzenveld receives a substantial inflow of deep, O₂-depleted groundwater, which is enriched in ammonium and phosphorus due to the subsurface mineralization of organic matter under sulfate-reducing conditions. This groundwater is mixed in the ditches during wet periods with O₂-rich runoff, and iron- and phosphate-rich drain water. Unlike natural catchments, the newly created, separated urban flow routes lead to mixing of water in the main surface water itself, shortcutting much of the soil and shallow subsurface. This leads to low O₂ and high ammonia concentrations in dry periods, which might be mitigated by water level management or artificially increasing O₂ levels by water inlet or artificially aeration of the main water canals. Further research is necessary how to optimize artificial urban systems to deliver a better ecological and chemical status of the surface water.

Keywords: Amsterdam; Groundwater quality; Groundwater-surface water interaction; Nutrients; Radon; Surface water quality.