Our team is working on a project in a European city, where high levels of groundwater are a problem. This problem affects many European cities that became industrialized in the 18th and 19th centuries. Because of industry\'s heavy use of groundwater from above the first impermeable layer, the water table in these cities sank during the 18th and 19th centuries. Subsequently all the transport infrastructure (including subway systems, underground garages) and even cellars in residential units were built with the low water table in mind. Starting in the 20th century, industry moved out of the cities and the heavy demand for groundwater ceased, resulting in the water table rising again. In fact, the problem has become so serious that low-lying subway tunnels and parking garages are regularly under water and the affected cities have to spend considerable amount of money to keep pumping the water out of these areas. In the city where our project is located the local authority actively encourages (in publicly available documents) the abstraction of this groundwater from above the first impermeable layer, as it lowers the costs of the city having to pump the water themselves. They prohibit recharging the groundwater and actively discourage projects where water is extracted and then returned directly to the water table (e.g. ground-water heating systems). They have a clearly stated preference for projects that abstract water and do not return it to the water table. It is also worth noting that this water is non-potable and the city\'s drinking water comes from a protected aquifer underneath this upper water table. The two layers of water are physically separated by an impervious layer and there is no chance of mixing between them. Therefore withdrawal of the water above the first impermeable layer under the city would not affect the availability of drinking water for the city. We understand that LEED generally promotes groundwater recharge and discourages the use of natural subsurface water resources for irrigation, because of the many issues regarding water resources in the USA. However, considering that the circumstances in this case are very different and the water we would use is non-potable, non-desirable and would help alleviate some of the city\'s flooding problems, we would like to know whether the use of this water for landscape irrigation and toilet flushing in our building would receive credit for water efficient landscaping (WEc1) and water use reduction (WEc3). The design team is proposing the use of this water in conjunction with water conserving design strategies which include native landscape species, drip-type irrigation systems, and low-consumption fixtures for faucets, showers and toilets.
The applicant is proposing to reuse groundwater in effort to achieve exemplary performance for water efficiency measures WEc1 and WEc3. This strategy can be considered innovative if the removal of foundation water is made in order to keep the building dry; sinking a well specifically for irrigation water is not acceptable. For a project in this location, because the groundwater would otherwise have to be disposed of if not used for irrigation or sewage conveyance, the reuse of this groundwater for water efficient landscaping (WEc1) and water use reduction (WEc3) merits an innovation point. Please note that using non-potable water for faucets or showers in WEc3 would present a health concern, and that the team should consider local code for acceptability of non-potable faucet water. The water use would need to be properly documented and calculated per Credit requirements. A narrative explaining the circumstances and proof of the impervious layer between the drinking water aquifer and the non-potable ground water would be of particular importance. Applicable Internationally; Europe.