Detailed Geophysical Mapping and Hydrogeological Characterisation of the Subsurface for Optimal Placement of Infiltration-Based Sustainable Urban Drainage Systems

Abstract

The continuous growth of cities in combination with future climate changes present urban planners with significant challenges, as traditional urban sewer systems are typically designed for the present climate. An easy and economically feasible way to mitigate this is to introduce a Sustainable Urban Drainage System (SUDS) in the urban area. However, the lack of knowledge about the geological and hydrogeological setting hampers the use of SUDS. In this study, 1315 ha of high-density electromagnetic (DUALEM-421S) data, detailed lithological soil descriptions of 614 boreholes, 153 infiltration tests and 250 in situ vane tests from 32 different sites in the Central Denmark Region were utilised to find quantitative and qualitative regional relationships between the resistivity and the lithology, the percolation rates and the undrained shear strength of cohesive soils at a depth of 1 meter below ground surface (m bgs). The qualitative tests enable a translation from resistivity to lithology as well as a translation from lithology to percolation rates with moderate to high certainty. The regional cut-off value separating sand-dominated deposits from clay-dominated deposits is found to be between 80 to 100 Ωm. The regional median percolation rates for sand and clay till is found to be 9.9 × 10−5 m/s and 2.6 × 10−5 m/s, respectively. The quantitative results derived from a simple linear regression analysis of resistivity and percolation rates and resistivity and undrained shear strength of cohesive soils are found to have a very weak relationship on a regional scale implying that in reality no meaningful relationships can be established. The regional qualitative results have been tested on a case study area. The case study illustrates that site-specific investigations are necessary when using geophysical mapping to directly estimate lithology, percolation rates and undrained shear strength of cohesive soils due to the differences in soil properties and the surrounding environment from site to site. This study further illustrates that geophysical mapping in combination with lithological descriptions, infiltration tests and groundwater levels yield the basis for the construction of detailed planning maps showing the most suitable locations for infiltration. These maps provide valuable information for city planners about which areas may preclude the establishment of infiltration-based SUDS.

Groundwater Potential Zone Classification Using Geospatial Approach

“…Soil texture and structure relate to infiltration and percolation which contribute to groundwater recharging. Previous studies have shown relatively higher percolation in sand-dominated units than clay units (Andersen, 2020). In addition, compacted sediment, which limits the pores, affects infiltration ability.…”

Suitability Zoning for Sustainable Drainage Systems (SuDSs): Application in a Basin in Southern Brazil

“…Urbanized areas have been increasing in developing countries, mainly due to population growth; population migration from smaller to larger urbanized areas; regional displacements due to social and economic conditions; and, within an urbanized area, displacement from more central to peripheral areas [1,2]. This increase in urbanized areas has led to the occupation of areas with very distinct environmental characteristics, from aquifer recharge areas to areas subject to hazardous events with different natural, quasi-natural, natural-technological, and anthropogenic sources [3][4][5][6].…”

“…Several procedures have been proposed to alter the partitioning between surface runoff and infiltration, with an emphasis on sustainable drainage systems (SuDSs) used in urban environments, roadworks, and special-use areas such as industrial parks. SuDSs have been developed since the 1990s, with a set of techniques and measures that can be adopted depending on the land use characteristics and, especially, on the environmental components, as shown by [1,2,[8][9][10][11][12][13][14][15][16][17][18][19].…”

“…When choosing and implementing a SuDS or combination of SuDSs, the following are the fundamental objectives: (1) decrease the surface runoff volume to minimize possible flooding, silting, and linear and marginal erosion, as well as overtopping of containment structures in drainage channels; (2) ensure that infiltrated waters do not trigger any events of a geological, geotechnical, or hydrological nature that may damage the elements that compose the anthropogenic environment and/or alter natural conditions, affecting biodiversity; and (3) ensure that infiltrated waters are not contaminated and, consequently, do not contaminate geological materials and subsurface waters.…”

Proposta De Procedimentos Para O Zoneamento Quanto a Adequabilidade Para Sistemas De Drenagem Sustentáveis (Sds) Baseada Em Características Geológicas E Geotécnicas: Aplicação Na Bacia Do Córrego Do Gregório, São Carlos (Sp), Brasil

“…Com o objetivo de alterar a proporção entre o escoamento superficial e a infiltração, diversos procedimentos têm sido propostos com ênfase aos Sistemas de Drenagem Sustentáveis (SDSs) que tem seu desenvolvimento a partir dos anos 1990 com diversos trabalhos em diferentes países, principalmente, na Inglaterra (Butler & Parkinson, 1997;CIRIA 2000aCIRIA , 2000bCIRIA , 2006; Dearden & Price 2011, 2012Dearden et al, 2013;Zhou, 2014). A adoção desses sistemas e suas instalações dependem de um grupo de características dos componentes do meio ambiente que interferem e, mesmo, inviabilizam a adoção dessas alternativas que visam minimizar os problemas gerados pelo aumento do escoamento superficial e, assim controlem os problemas decorrentes das mudanças geradas pela urbanização.…”