Water-Sensitive Cities in Israel
Tuesday, July 14, 2015 9:17 AM
The opening workshop of the research program
The opening workshop of the water-sensitive cities research project took place on July 9th at the KKL-JNF Center at Eshtaol. Participants included leading experts and researchers, representatives of local authorities, representatives of the Israel Water Authority and other officials involved in the field. The research center was established by KKL-JNF in conjunction with JNF Australia, the Hebrew University of Jerusalem, the Technion (Haifa), Ben Gurion University of the Negev and Melbourne’s Monash University in order to create a high quality sustainable urban environment.
Water sensitive city program
The innovative Water Sensitive Cities program is accompanied by a number of research projects that examine different aspects of water-sensitive cities and explore ways to adapt this vision to the unique conditions prevailing in Israel. The Water Sensitive Cities study day, held on July 9, provided updates on the progress of the research and an opportunity to discuss how to interest the relevant professionals and officials in the issue of water-sensitive cities.
KKL-JNF Development Project Director Yossi Schreiber, who opened the proceedings, pointed out that KKL-JNF had begun to address national water issues back in the 1980s, mainly by proposing alternative water resources for agriculture. “At first people looked at us as if we were mad - who had ever thought of making use of sewage water?” he asked rhetorically. “Today, however, this seems an obvious solution.” He added: “Normally we export water technologies, but in this case we’ve decided to learn from Australia and adopt their water-sensitive city approach.”
Yehiel Cohen, Deputy Director of KKL-JNF's Central Region, told his audience: “We cannot exaggerate the importance of water-sensitive cities. The research is being conducted by the finest minds gathered here, who will help us to promote the issue and thus make a substantial contribution to Israel’s water economy.”
Zeev Kedem, Director of KKL-JNF’s Israel Fundraising Division, emphasized the importance of the part played by JNF Australia, which had raised the subject and promoted the initiative. Joe Krycer, who recently gave up his position as Director General of JNF in Melbourne and immigrated to Israel, also received special mention for having played a major role.
Dr. Yaron Zinger, who received his PhD from Melbourne’s Monash University and introduced the first biofilters to Israel using technology developed in Australia, explained that water-sensitive cities are characterized by their ability to come up with sustainable solutions that make optimum use of their limited water resources with the help of suitable technologies and increased public awareness.
He explained that according to this approach, a city can be regarded as a catchment basin for water supply when the urban environment supports the natural environment and provides it with ecosystem services. Local residents share in the decision making and maintain a lifestyle that serves as a basis for sustainability in their city.
“In a world beset by climate change and the changing needs of mankind, the development of water-sensitive cities is vital for both human beings and the environment,” said Dr. Zinger. “Our goal is to transform a problem into a resource. For this, however, technology alone is not enough: we have to adapt this approach to suit conditions here in Israel. I believe that our scientific expertise can be expanded into a national project that will supply cities with clean and freely available water resources, conserve the ecology of the environment and offer a solution to extreme events such as flooding and drought.”
Accumulating scientific knowledge
The six research projects underway at the center, all of which examine different aspects of water-sensitive cities, were presented in the course of the study day.
Professors Tal Alon-Mozes and Elissa Rosenberg of the Technion spoke about water-sensitive planning in an Israeli context. “As planners, we cannot look at things exclusively from the engineering point of view,” said Professor Rosenberg. “We must also take their social and ecological aspects into consideration.”
Their research focuses on the evaluation of existing water-related projects and their examination from hydrological, ecological, social and economic standpoints. The work is still in its initial stages, and the researchers are currently engaged in drawing up a list of projects for examination and in developing the methodology necessary for their analysis.
The plan is to evaluate the selected projects by means of different yardsticks such as water quality, water quantity, flood prevention, ecological repercussions, their effect on the urban fabric and their social and economic implications.
“Runoff water is a very important issue in planning, but there appears to be a great discrepancy between how important ideas are planned and the way they are implemented,” explained Professor Alon-Mozes. “Our group’s objective is to try to uncover the reasons for this discrepancy between theory and practice.”
The projects under consideration as candidates for evaluation may be large or small, new or old and located anywhere in Israel. They include Raanana’s Uri Gordon Park, Hezekiah's Pool in Jerusalem, Pekiin’s Fountain Square, Nesher’s Shmuel Reinish Park, the Ramla Biofilter, the Kfar Sava Biofilter and green neighborhoods in Yavneh, Ganei Tikvah, Netanya, Beersheba, Kfar Sava, Kibbutz Nir Oz, Holon and Tel Aviv, where runoff water was taken into account at the planning stage.
Adi Haft, a student on the team led by Professor Rony Wallach of the Hebrew University, presented research into the quality and quantity of urban runoff water in Israel from the point of view of different types of land use. The site selected for the research was a catchment basin in eastern Kfar Sava that extends over an area of some 3,000 dunam (approx 750 acres) and includes three sub-basins: a residential area, a commercial area with light industry, and shopping centers.
“It’s important for us to examine separately what takes place in each individual area, because if we don’t mix all the surface runoff together we may discover that the water in certain areas is of sufficiently high quality to be used as is, without treatment; or, alternatively, we may conclude that it is best to construct biofilters suitable for the entire region.,” Adi Haft explained. The initial conclusions of this research are expected to emerge next winter.
Professor Eviatar Arel of Ben Gurion University’s Desert Research Institutes gave a lecture on water-sensitive strategies and microclimates. “A microclimate cannot be improved by injecting water into the ground, only by making use of that water for local vegetation,” he emphasized. “The vegetation can help to lower the temperature, while the surface runoff can reduce the quantity of water necessary to sustain it.”
This research is designed to examine how existing urban conditions can be modified in order to improve the flow of runoff water, and to investigate various different types of vegetation and their influence on temperature and the energy balance at varying distances from vegetation concentrations and bodies of water.
Professor Asher Brenner of the Environmental Engineering Unit at Ben Gurion University’s Faculty of Engineering Sciences presented the concept of hybrid biofilters that combine different processes. He explained that since Israel, unlike Australia, has a prolonged dry season, a biofilter could be used for runoff in wintertime, while in summer it could purify polluted groundwater that would later be injected back into the aquifer.
Professor Brenner explained that inside the biofilter, a variety of processes take place in different environments. These include the biological breakdown of scraps of organic material, the physical removal of solids, heavy metals and pathogenic microorganisms and the adsorption of heavy metals and remnants of organic material.
This research is designed to explore how best to plan and operate a hybrid biofilter in order to achieve the necessary high water quality all year round while conserving the biomass of vegetation and bacteria. Filtering mediums, different types of vegetation, organic supplements and maintenance at different seasons of the year will be among the variables investigated.
Initial results show that cotton is the most efficient medium for breaking down nitrate, a pollutant commonly found in groundwater. The upcoming stages of the research will include the construction of columns of vegetation where the processes that take place within the biofilter can be reproduced.
Dr. Yael Gilboa, a member of the research group led by Professor Eran Friedler of the Technion, talked about the development of the vision of water-sensitive cities. She explained that population growth, increasing urbanization and climate change have caused groundwater levels to drop, resulting in a shortage of accessible water.
“All these factors have led to a need for sustainable planning that will satisfy the requirements of the present without impinging upon future generations’ ability to meet their own needs, and promote improved quality of life without damaging natural resources,” said Dr Gilboa. “This research is designed to help us develop an overall vision for water-sensitive cities in Israel that will encompass scientific, economic and social aspects of the issue.”
Dr. Yaron Zinger summed up the academic part of the day’s events with a review of the three pilot projects underway in Israel’s Kfar Sava, Ramla and Bat Yam. “In most Israeli cities today the runoff water flows from the streets into the rivers and the sea, causing environmental pollution, a drop in groundwater levels and the salinization of wells,” said Dr Zinger.
The biofilters are designed to collect the runoff water that carries pollutants through city streets, purify it by means of environmentally friendly biological and physical processes and return it to the aquifer as clean water by means of wells dug nearby.
This process prevents wastage of precious water, keeps rivers and beaches clean and creates attractive gardens in the heart of the city. In older neighborhoods such as those in which the biofilters of Ramla and Bat Yam are located, the project can also help to prevent flooding during rainstorms.
Dr. Zinger explained that the biofilter contains from five to seven layers of sand and vegetation. The upper layer is covered with plants of a special type that help to purify the water, while the lower levels, where little oxygen can penetrate, encourage the development of bacteria populations that promote water-cleansing processes. This system can efficiently remove a variety of pollutants such as heavy metal particles, organic material and oils.
The monitoring systems installed show that the polluted runoff water that flows into the biofilter emerges from it almost clean enough to drink. The expectation is that in the future this water will be used both to boost groundwater reserves and for the irrigation of gardens and crops.
The lectures were followed by a panel in which the proceedings were summed up. This session was chaired by Professor Eran Friedler of the Technion, who told those present: “We’re just at the beginning of the road. Thanks to our combined efforts we are amassing a great deal of knowledge and increasing the prospects of implementation. We shall continue to meet in order to keep each other updated of future developments.”
Getting out into the field
After the discussions were over, the researchers abandoned the lecture hall in favor of an excursion to inspect what is actually happening now in the field. Dr. Zinger took them to visit the two new biofilters in Ramla and Bat Yam that were established by KKL-JNF in conjunction with JNF Australia. These facilities joined the older biofilter in Kfar Sava, which was installed in 2010 with the support of JNF Australia and KKL Mexico.
Visitors to the biofilters often expect to be confronted with ugly water purification plants, and are pleasantly surprised to discover that these facilities consist of attractive pools clad in greenery and surrounded by well-kept gardens that offer benches to sit on, explanatory signs for the benefit of the general public, footpaths and cycle trails.
Each biofilter has a capacity of around one hundred cubic meters. During periods of significant rainfall, each facility may fill up and empty out several times in succession, and over the course of the year, this can add up to thousands of cubic meters of water. Last winter the biofilters in Bat Yam and Ramla proved themselves as efficient as their predecessor in Kfar Sava.
In view of the success of these initial trials, the researchers’ ambition now is to make the biofilter a standard feature for cities throughout Israel, in order to boost the country’s water economy and to help keep the environment clean.