Short general project overviewRealize, test and investigate the effects of a system for rainwater retention on roofs and to use this water for maintenance of landscaping in Chinese cities, so that building owners can comply with the emerging laws and regulations and a ‘green image’.Green Art International is an advisory and architectural firm for natural techniques in the field of landscaping and landscapes. In addition to designing and advising, she conducts technical, ecological and environmental studies and develops knowledge in this field worldwide. Water use and water retention are important topics in the studies. In the Netherlands, the importance of water saving and retention is increasing, partly because of the groundwater level and the salinization of the soil. Green Art International has therefore specialized in the water management problem in combination with landscaping and green roofs. This includes water retention, soil infiltration, irrigation, storage and other applications such as cooling of buildings. The innovative urban water system (Hanging Water Tank) offers a solution to the climate and water problems in densely populated cities.Project goals1. (Further) development of the total product Hanging Water Tank (HWT);2. Collection of relevant test results for the benefit of the HWT;3. Awareness for water storage among governments, building owners and residents in China so that water is on the agenda of the decision-making authorities and more attention is paid to the possible solutions.Initial activities and results of the projectThe activities consist of testing and demonstrating the HWT concept:- Applying the system to different types of roofs, different heights of existing buildings and new buildings with new building modules. The consortium will carry out a pilot in the city of Dalian, Tianjin (Beijing).- Application of plastic water tanks which are frost and heat resistant. The water tank equipped with a small pumping system will be an eye-catcher and landmark of the building.- Analysis of the costs and benefits of the retention system at all three levels (roof, façade and infiltration).- Clarity about the possibilities and business case of the HWT system in combination with solar panels on a roof.- The ambition is to install within 5 years the HWT system at 5% of Dalian’s roof area. (A reference is Chicago, covering 20% of the total roof area.Test results to be achieved for the HWT:- Define the percentage of paved surface that must be connected to a smart water system in order to make a significant difference in the risk of flooding.- Define the reduction of CO2 emissions by using this system.- Find out the distance that water can travel under the pressure of the height. How far from the precipitation point can water be used without the intervention of pumps?- Define the relevance of the HWT system in the event of extreme rainfall compared to situations without such a system.- Investigate the contribution of the retention system to prevent dehydration and to contribute to heat absorption of green areas in a high urban environment. - Investigate the quality of water. Awareness of solutions to water problems with relevant parties.- Getting recognition and support for the HWT concept from the local authority and municipality.- Demonstrate and highlighting the benefits of the HWT to building owners and users in order to gain awareness of the HWT as a solution to the water problem.Update on the project resultsThe project has been executed in line with the original plan. Some plants are vulnerable for frost.The HWT concept proofed to be working well. After the project some projects has been realized in China, although most of them for western clients. Green Art International sets up a local entity, with Chinese staff to further enrol the concept.