American professors Dr. Brad Lancaster and Dr. David Eisenberg discussed water harvesting and management with the use of green building materials in Jeddah and the Kingdom at a meeting held in celebration of Global Earth Day at the Jeddah Chamber of Commerce and Industry at the weekend. Dr. Eisenberg an expert on green building materials said that the use of such materials was a challenge in big cities like Jeddah. Green building materials are natural, low tech and traditional building materials used to conserve resources and protect natural habitats and local culture. He explained the importance of indigenous building techniques and materials in raising awareness of the environment. “It is a challenge and it is a mix of things,” he said. “A lot of materials which are green in America are not green here. You have to look at the whole picture and it's very important to pay attention to where you are. What's green in one place is not green in another.” “I can think of applications where steel, for example, can be a very green material. Concrete has been improved a lot but it has too much body energy and a lot of CO2; so there is a big climate impact, but it is a very durable material. So I think that these materials should be used carefully,” he explained. Green buildings are more than just focusing on the materials used in their construction. It is a question of the overall performance of the building. So if you can use mostly green materials and also employ other materials to increase the overall performance, durability and life of the building, that would be overall a greener building than one using only low tech and impact materials, he said. “I think wherever it is possible to use more natural materials, it is a good idea, just like we used to do in the past. Many of our old traditions have been forgotten,” he explained. Overall it is a process of looking backward and forward at the same time and paying attention to what is the effect on the environment so that we can leave a safe environment for coming generations. Dr. Lancaster, an expert on water harvesting and water management, promotes methods to conserve and exploit available water resources such as rainwater, and household waste water. He pointed out that rainwater wastefully drained out of the cities pours into streams and rivers picking up contamination and pollution on the way, which can actually lead to a lower quality of water downstream. However, if we can instead harvest the water as close as possible to where it falls, we can improve storm water quality, and we can also reduce our need to import water from desalinated sources which are very inexpensive for the users but very expensive to produce. In other areas where the fresh groundwater table is dropping, we can lessen the rate of pumping water. The whole idea is to recognize the free high quality inexpensive sources of water we have and utilize them first before we become involved in importing or desalinating water. In doing this we can improve the quality of the community and the environment. “The tradition in the Asir region of the Kingdom,” Dr. Lancaster said, “is to harvest rainwater and runoff. And that tradition is still being followed.” “There was also a tradition in old Jeddah of harvesting rainwater. Buildings were built so that the water would be directed off the roof to the central courtyard and then there would be a tank to collect the water. So water harvesting is not a new idea. It is something that has been happening in the Kingdom for hundreds of years,” he said. In Jeddah the climate is hot and humid and air conditioners produce a lot of condensation which causes damage to buildings. “In hot humid climates like Jeddah, it is cold and dry inside air conditioned rooms while outside the air is hot and humid. This produces water which is why the walls of buildings are full of moisture even when it doesn't rain,” Dr. Eisenberg explained. The buildings are creating unhealthy conditions for the people who are living in them because this was not understood when the buildings were designed. “Green house materials like clay are very effective in moderating moisture and by mixing other materials like straw with the clay, we can improve the quality of the material, minimize the harm to our health and increase the benefits of life,” he said Dr. Lancaster said that in most cities streets are usually built with trees in the middle on small hills so all the rain that hits drains off. Even the irrigation water runs into the streets and makes puddles which help to breed mosquitoes. “If we instead plant the trees in basins on the sides of the street instead of on hills, the rain will help to irrigate the trees and the trees will use the water so there will be no puddles or mosquitoes,” he said. “In Jeddah there are 15 mm or so of rain in a year. The integrated approach makes the rainwater go further and makes rain a resource and not a problem,” he said. “It will also decrease the flooding of the streets and reduce some of the heat from the atmosphere. So when you plant trees, you are actually planting solar powered air conditioners,” he explained. In Jeddah there are already tanks in the houses as city water does not come every day. “You can have tanks which collect the rain when there is rainfall and this can help when the city water doesn't come,” he said. “Jeddah has humidity which is an advantage for the city. You can harvest the air conditioning condensation. All of these air conditioners expel water, which breeds mosquitoes. This water can be used for harvesting plants as under every air-conditioner that is dripping water, you can put plants. And if that is not possible then you can collect the water in tanks and reuse it and thereby overcome the scarcity of water,” he explained. When you save energy you save water and when you save water you save energy as they are related to each other. “ If you can design a building that cools itself, then you will reduce the energy use and save the environment from pollution,” Dr. Lancaster said.
