Recharging aquifers through rainwater harvesting is a key part of India’s strategy for providing a year-round water supply since frequent and intense droughts and surface and groundwater shortages are a challenge. It is particularly important as much of the yearly rainfall in this region occurs during only a few weeks of the monsoon season. Companies and individuals can compare their monthly or annual water use against the amount they are potentially able to capture and use to replenish groundwater sources. This water balance can tell them if they are “water balance positive” or “water balance negative”, by using less or more than they replenish.
From the overall hydrologic water cycle, this concept is useful to consider even if obtaining water from a surface water source and replenishing groundwater. Many companies consider their “water footprint”, both at a site level and associated with their supply-chain. Most businesses have a supply-chain water footprint that is much larger than their operational water footprint.
To help our client demonstrate its water stewardship, WSP conducted field studies and reviewed the rainwater harvesting design and construction records. This helped us determine how effective the current methods were for redirecting water into underground aquifers. Our team also conducted an analysis of the techniques used to collect data on water flows, the maintenance measures in place for the rainwater harvesting methods and how communities were involved in the process. Through this work, WSP found several areas in which the client could optimise its harvesting and underground aquifer recharging methods.
Our client is now better able to demonstrate its stewardship by harvesting rainwater and using it to recharge the underground aquifers that hold groundwater. Harvesting methods include collecting water from a building’s roof and redirecting it into the ground, as well as building small catchment dams across watercourses so that water is pooled and can then soak into the ground. In some cases, well-like excavations are made and then filled with gravel to better direct water underground.
* This work was performed by Golder professionals who joined WSP in an acquisition completed in 2021.