Skip to main content

Water buffering and drainage in urban areas by using drainage blocks under the road

Periodic Reporting for period 1 - Bufferblock (Water buffering and drainage in urban areas by using drainage blocks under the road)

Reporting period: 2019-06-01 to 2019-12-31

Heavy rainfall will occur as a result of climate change. A rise of temperature of land and (sea)water will intensify rainfall into storm surges. The problem is not something that will happen in the distant future but has already started! Since 1920 the number of days with rainfalls over 20mm has almost doubled. Due to this change, more and more cities are now faced with the problems of streets that are flooded with rainwater. The large amounts of water cannot be infiltrated in the ground due to asphalt or pavers and is dissipated in the sewer. An average sewer overflows with precipitation of more than 30 mm / hour, leading to flooded streets and blocked passages.
Our innovation, Bufferblock, will provide a cost-effective solution for the responsible government or area developer that offers maximum storage of surplus rainwater with minimal space. It provides an innovative and easy way to retain and distribute water at times when the normal sewer is not sufficient. Though governments and area developers are in principle not legally liable for natural disasters like flooding, they seek for different means to deal with flooded streets, parking lots and cross-roads. Given the climatic developments, it is indeed wise to take into account the foreseeable weather forecasts of the future for any construction, replacement or reconstruction. Upgrading the sewer is the first step, but not always sufficient. Water management by digging trenches and ponds is another, more natural solution, but it takes up a lot of space that is already scarce in the builded environment. The best alternative solution is to store water (temporarily) in a catchment basin, under or near the road. We developed a solution for a water storage facility, directly under the road surface, compact and strong enough to withstand heavy traffic. It is built with patented concrete blocks (WO2018143808), which form an open construction under the street surface. An average block of 45 cm height with 62,5% open space can retain 266 liter/m2.
Our solution is cheaper in euros per m3 of storage capacity compared to the alternative plastic crates, it requires less installation depth, is better in withstanding traffic loads and is easier to install. In addition to the flood prevention during heavy rainfall, the infiltrating capacity of our solution also prevents dehydration of the soil in urban areas as a result of hot seasons. This is because rainwater doesn’t go directly to the sewer but will infiltrate in the soil through the open space at the bottom of Bufferblocks. If cities have too much hard surface and no natural infiltration capacity, a city can suffer from so called Heat Stress. This happens when the city cannot get rid of its heat due to lack of groundwater that can evaporate and thus cool the city. The system of Bufferblock can regulate the surplus and the lack of water in the city.
Roadmap feasibility study Bufferblock

But which country is best suitable for the Bufferblock on rational and data based considerations?

All European countries are researched on different parameters to determine which country or countries are most suitable for introducing the product of Bufferblock.
The ranking is determined on the basis of index data such as GDP per capita, International IP index of GIPC, Water Index cities by Arcadis e.o.
The weighed score gives the following ranking:

1 United Kingdom 4,64
2 Germany 3,96
3 Italy 3,68
4 France 3,56
5 Ireland 3,14
6 Spain 2,78
7 Denmark 2,60
8 Sweden 2,59
9 Poland 2,53
10 Belgium 2,37

After the ranking of countries other parameters have to be researched in order to designate a country as the next introduction country.

Step 1: Mapping the largest cities in the country (>500.000)

Step 2: The next research criteria for each city are as followed:
o Soil
Current constructions/lay-out (paved, unpaved, roads, public transport, facilities, boundaries, inventory of use/ ownership, location of ecological structures)
Ground level
Soil Types (Porosity soil, permeability of soil and resistance)
Population density (Inhabitants p/km2, Paved surface)
o Groundwater levels
o Surface water
Nearby rivers or surface water
Water catchment area
Nearby water storage systems (surface or subsurface)
o Rainwater and sewer systems
mm of precipitation/ type of catchment system
Type of sewer system
o Type of water excess?
o Main competitors and competitive solutions.
o Who are the stakeholders and has decision making influence.
o Money spend on climate adaptive measurements? Subsidies?

Step 3: Mapping the data in a radar diagram per city per country

Step 4 Legal Framework
o IP
o Rules and regulation on national and local level for subsurface water storage and infiltration
o Needed Certification
o Product approval and certifications
o Technical adjustments needed for approval?
o Needed tests /rapports

Step 5 Business plan
o Learnings implementation Netherlands
o Initial market segments selected countries
o Development implementation and growth strategy
o Design distributor network
o Implementation strategy

Step 6 Commercial out roll
o Choosing producer for product Bufferblock
o Sales channels
Where extreme weather events become more intense and/or more frequent, the economic and social costs of those events will increase. The rapport of EASAC mentions: “It is not primarily the change in the mean of climate variables such as temperature, precipitation or wind, or in derived variables like storm surge or water runoff, but rather the changes in the extremes of these variables that pose serious risks. Future extremes could become the most potent drivers of economic and social impacts.” On average, the costs for insurance companies is predicted around 90 million euros per year. According to some climate scenarios, this will increase to 200 million euros per year in the future. Because the number of heavy rainfall events increases, just like the intensity, this problem will only increase in the coming years.
Along with the increase in precipitation there is also an increase in long dry spells. Due to the dense paved urban areas, surface water is almost unable to infiltrate into the ground and is lead away via the sewers. In cities we see a decrease in the groundwater recharge when there are no large green areas or infiltration systems in place. Bufferblock is able to regulate the surplus and shortage of water in urban areas and contributes to a safer, healthier and sustainable living environment.
We've experienced that the need for climate adaption in cities is very actual. During the feasibility study we have already had several requests to deliver the product to infrastructural projects. By doing the research we are now able to shorten the implementation timeline and are able to deliver the Bufferblocks, not only in one segment in one country, but in more market segments in different countries.