Identification of the Optimal Locations for Artificial Infiltration

Monday, December 4, 2017: 11:30 a.m.
101 D (Music City Center)
Max Halkjaer , Water and Natural Resources, Aarhus, Rambøll, Aarhus N, Denmark
Peter Thomsen , Water and Natural Resources, Aarhus, Rambøll, Aarhus N, Denmark

pls note: we would like to be part of the special session on geophysics. Reference John Jansen

text:

Inhomogeneity of topsoil often exceeds what can be verified by boreholes. Non-invasive Geophysical investigations can efficiently increase our knowledge and thereby minimized structural uncertainties in near surface hydraulic modelling.

High resolution geophysical multi coil Ground Conductivity Meter DualEM421 investigations have shown to be a successful tool for detailed mapping of the soil conductivity within the upper 5-7 m. Combined with shallow boreholes, hydraulic head measurement and simple infiltrations test, detailed description of the hydraulic conditions of the near surface groundwater is obtained. Surveys can be scaled according to size of area and needs for resolution.

Experiences shows a strong relation between electrical conductivity measured with DualEM421 and geological conditions which again are strong related to hydraulic conductivity obtained by infiltration test e.g. double ring infiltrometer test. Site specific relation leads to significant improvement of data input for near surface 3D geological and hydraulic modelling, and thereby optimizes the assessment of hydraulic consequences for specific LID/SuDS and aquifer recharges solutions.

Knowledge of the spatial distribution of high permeable sand layers and less permeable clay layers is crucial when pointing out the optimum location for artificial infiltration.

LID/SuDS solutions for handling rainwater are often a necessity and an integrated part in the development of urban and suburban areas. Aquifer storage and recovery (ASR) is a commonly used tool for sustainable water resource management. Beside rainwater the reuse and infiltration of treated wastewater is an important source for maintaining water availability in water stressed environment.

Presentation will showcase example from both urban and suburban investigation, where integrated investigation has provided an improved knowledge and minimized uncertified when planning LID/SuDS solutions.

Max Halkjaer, Water and Natural Resources, Aarhus, Rambøll, Aarhus N, Denmark
Max Halkjaer has a +20 year career as a hydrogeophysicist. He obtained his Master degree in geophysics at Aarhus University, Denmark in 1995. He has contributed to a large number of projects across the world with a focus on protecting groundwater aquifers and groundwater sustainability. With an entrepreneurial mindset he has been involved in the development of GIS based tools used for analyzing water quality, processing geophysical data and interpreting the geometrical extent of aquifers. He is the co-founder of the company SkyTEM Surveys providing airborne geophysics developed specifically for groundwater mapping. He has comprehensive experience with assessing and modeling the interaction of fresh and saline water in arid as well as very humid geographical areas.


Peter Thomsen, Water and Natural Resources, Aarhus, Rambøll, Aarhus N, Denmark
Peter Thomsen is a respected geophysicists currently employed at Ramboll, a large consultant company operating in most parts of the world. For the last 15 years he has been involved in the Danish national groundwater mapping program. He graduated (M.Sc. in environmental geophysics) from University of Aarhus in 1998, and apart from Ramboll, has been employed as a research assistant at the University of Aarhus, Geoscience. In this position Thomsen had a great influence on development of geophysical equipment, setting up standards and optimizing measurement procedure used in the geophysical mapping program.


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