Prioritising sewersheds based on groundwater infiltration probability: A geospatial approach

Area of Science:

• Environmental Engineering
• Hydrology
• Geospatial Science

Background:

• Groundwater infiltration (GWI) in sewer networks is a critical but understudied issue, impacting network capacity and maintenance.
• Previous assessments of GWI have lacked comprehensive, large-scale evaluations of sewersheds.
• Increasing water inputs strain sewer networks, necessitating better GWI management strategies.

Purpose of the Study:

• To prioritize sewersheds based on a quantitative GWI metric across South West England.
• To address the gap in large-scale, comprehensive GWI assessments for sewer networks.
• To guide efficient resource allocation for GWI research and field surveys.

Main Methods:

• Utilized geospatial technology and a fuzzy-analytic hierarchy process (F-AHP) for high-resolution GWI scoring (10 m × 10 m).
• Incorporated 13 thematic layers, including sewer properties (material, depth, age) and hydrological factors (groundwater productivity, river proximity).
• Conducted sensitivity analysis to identify key influencing factors on GWI.

Main Results:

• Developed a prioritized map of sewersheds based on GWI scores across South West England.
• Identified installation date, groundwater productivity, river proximity, and asset performance during low precipitation as key GWI influencers.
• Highlighted challenges including data scarcity, scale inconsistencies, and limited observation wells.

Conclusions:

• The study provides a framework for prioritizing GWI research and interventions in sewer networks.
• Findings enable more efficient allocation of resources for managing groundwater infiltration.
• Future work should focus on expanding monitoring and improving hydrological models in data-scarce regions.