citizen climate adaptation project
Basic information
Project Title
Full project title
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Project Description
36 Citizens in the city of Nijmegen (The Netherlands) who live in an old monastery build themselves a community green water infiltration and rainwater harvesting system. The rainwater from the roof flows into a tank and when the tank is full the water flows into the ground, using infiltration crates. Everything is disconnected from the sewage system. Water is used to flush toilets. Money was saved by self-activity and an interesting investment towards the future price increase of drinking water.
Project Region
EU Programme or fund
Description of the project
Summary
36 Citizens in the city of Nijmegen (The Netherlands) who live in an old monastery build themselves a community green rainwater infiltration and rainwater harvesting system. It's working fine. The rainwater from the roof flows into a tank and when the tank is full the water flows into the ground, using infiltration crates. All the rainwater tubes are disconnected from the sewage system.
Saving money by self-activity made the project also an interesting investment towards the future price increase of drinking water for tenants and house owners. The ROI is expected to be 10 years if the water price remains constant and all the harvested water is used. But the water-price is rising above inflation for years now. It's expected that this will continue due to increasing challenges in drinking water purification so as the removal of medicines.
The amount of rain falling in heavy downpours, will continue to increase. This project helps the municipality with delayed draining to the sewage system, by the use of rainwater, or infiltration of green water in the case of overflow of the rainwater storage tank.
To raise the money for the project the tenants layed by every month a few euro's. Within a few years, the fund had 5000 euro's enough to buy the first hardware for the project. Realizing the installation from first sketch to first use lasted from 2009 to 2016. Because of the pilot situation the total overall cost ended up at 14000 euro's, 6000 more than was calculated.
The former monastery was bought by a social housing association (www.wbvg.nl) in 1988. This social housing association tries to keep the rent low by self-activity of tenants. The monastery itself is hired by a foundation with self-government and self-management by the tenants.
Key objectives for sustainability
To be an ambassador of climate adaptation. Doing something with the tenants "revolving green fund". Everything should be open source and available to everyone and should be easy to copy and a be a showcase.
The tenants just wanted to do their bit for a greener future. The way they did it, is easy to copy. A book and a film with all the do's and don't is underway, when the funds are available. A student will be asked to realize this for their study.
The installation works fine.
The installation is modeled by a student to help other citizens develop a rainwater harvesting and infiltration system.
Several press publications and social media messages have been made to spread the word.
A downpour in may 2018 was not able to push the sewage water back in the ground floor toilet rooms, like in other houses in the street.
In keeping the cost low they succeeded partially. Because of the pilot situation the installation did cost more, resulting in a longer pay back time.
There is a strong cooperation with education, neighborhood, housing association, government and small/medium enterprises.
Key objectives for aesthetics and quality
To place the rainwater tank, an old oil tank was removed. And the rainwater tank was placed in the hole that arose. Removing the old oil tank should have been done anyway.
The garden above the tank is renewed with drought resistant plants. It is now a playground for children a meeting place for the tenants and a beautiful garden in the middle of the city.
Key objectives for inclusion
All the tenants worked together, woman, men, young and old, students and laborers. Hundreds of photo's taken during the installation period, witness the cooperation of the citizens.
The work was a good place to have mutual contact, chat and learn about each other. Which has a follow up in the garden around a garden table above the underground tank.
Results in relation to category
There is cooperation with universities. A student of the Dutch University of Twente has made a software model of the installation that is available as open source on the internet. It was developed to let other citizen's design and and build an installation without all the faults we made. (https://essay.utwente.nl/77719/1/Geurts-Maartje.pdf)
Exchange of knowledge with students in water management is realized within the weekly “climate cafe” ( https://climatecafe.nl/groenblauwcafe/), led by professor Boogaard from the Dutch university of applied sciences Hanze hogeschool in Groningen. All these (online) climate cafe gatherings are afterwards available on YouTube (https://youtu.be/F4DvgGP8it4?t=3067).
There is cooperation with a local plumber, who realized the final difficult plumbing part and can help in case of future malfunction of the system. So small enterprises are also involved.
There is a cooperation with the municipality to work on measuring the quality of the rainwater. The municipality is measuring on its own wadi's and our installation is unique within the town, so the measuring is broaded to our installation. Does it contain PFAS? Heavy metals? Etc. Because of the infiltration it is important to know if we don't contaminate the blue water in the underground by infiltration. Information that is of common interest for all future projects. Also the silting up of the infiltration crates is studied together with the municipality. This is important because such an infiltration system is not really sustainable if it has to be dug up within a few years.
There is a new standardization around naming water. Green water is rainwater that infiltrates the soil. When it infiltrates deeper in the ground, it becomes blue water. Water in lakes and rivers (“surface water”) is also called blue water. After it is used by washing machines it becomes gray water and after if it is used for toilets it's called black water.
How Citizens benefit
Yearly more than 200 m3 rainwater is used and more than 600 m3 rainwater is infiltrated to help the groundwater level rise.
May 2018, we had a downpour in our street, where the rainwater pushed the sewage water back up in the toilet rooms at the ground floor. Except in our houses because of the discharge of rainwater into the ground.
Using rainwater for washing? Then you need less washing powder and no fabric softener because the water is soft. In summer rainwater is used for the garden and save scarce drinking water in hot periods.
In the neighborhood we created awareness about the use of rain water and about how to work ourselfs on the flooding of our street during downpours. A lot of neighbors came looking after our digging to get the rainwater pipes into the ground. About digging; we had to do it by hand. A digging machine was to big for the garden door. On the other side the underground is full of other pipes, glass fibers, electricity cables, water and sewage pipes that could have been damaged by a digging machine.
To use the water for washing and flushing toilets. The tenants use a so-called threefold filter (Coarse, fine and carbon). It is not drinking water, but all dirt is filtered out.
When the installation is payed off, the tenants spend less money on drinking water and taxes on sewage water.
Exchange of knowledge with universities, students, civil servants, other houses of the social housing association, neighbors, press, Dutch ministerial governmental regulatory body on water issues.
Another follow up is the realization of simple rear windows in the monumental monastery by self-activity, saving thousands of cubic meters natural gas. This is done at the inside of the building so the monumental character stays the same at the outside. The pilot showed a saving of 22% on the natural gas bill at 1/5 of the cost of isolating glass. This project is about 40.000 euro's and the rainwater project was meant to be a "finger exercise".
Innovative character
Normally these systems are used for the use of rainwater, or to infiltrate the rainwater. In this installation a combination is made. This was also new for the regulatory body within the municipality, but they let us do and are now glad we did it and presented it proudly as an example project on their website in 2018 when Nijmegen was the green capital of Europe.
There is still work to do. The tenants intend to make the installation now user friendly. There is no such installation worldwide automated. E.g. When do the filters have to be cleaned or changed? The filters should be changed or cleaned every year following the manufacturer. This is a waste of material, some filters last longer, other could be reused which is more circular. The water filters are also relatively expensive. For the moment the search after the right sensors, computer and open source software to realize this is going on. Experiments with reusing filters is taking place. Perfecting of this system needs more funding. Final goal is a fully automated system at an affordable price with an app to follow the performance of the system, rainfall and give warnings when e.g. filters have to be cleaned. This doesn't exist and is new in the whole world.
