Influence of soil temperature on the warming of drinking water in water distribution pipe networks – development of a soil model

Concerns arise about changes in water quality in water distribution networks (WDNs) due influence of Climate Change. Increasing air and soil temperatures could potentially warm up the drinking water during transport, such intensifying contamination and other harmful physicochemical processes in WDNs. Research and development efforts focus on improving models and tools for projecting these changes, particularly starting with heat transfer from surface to soil and soil to pipe.

The RBS wave GmbH specializes in network management solutions for drinking water supply, addressing challenges such as elevated temperatures (> 25°C) in WDNs. The University of Stuttgart's Institute for Water and Environmental Systems Modeling operates a prototype weather station, expanded to include soil temperature and soil moisture data for a comprehensive understanding of their impact on water heating in pipeline systems.  In addition to this weather station, instruments that offer precise information about the hourly/daily water state have been installed on the University’s campus. In an ongoing project, we aim to quantify factors influencing water temperature in the water network, utilizing sophisticated numerical models combined with advanced statistical approaches. We aim to address key questions, including how rapidly heat penetrates the soil, the duration of temperature persistence, and direct correlations between weather data and their impact on soil temperature, moisture, pipe materials, and water in the distribution network. Our objective is to identify the main factors influencing the warming of drinking water in WDNs. Thus, we combine the simulation and data-integration expertise of IWS/LS3 at SimTech with experimental expertise at the VEGAS facility and with problem understanding of the RBS wave GmbH. This will allow for the planning of resilient WDNs and for the implementation of effective measures to maintain safe temperature ranges for drinking water (e.g., optimized laying depth, filling material, insulation, vegetation, and more).