River cleanups are a complicated and tiring business that entails endless battles to obtain funding, coordination among a slew of agencies and government ministries and repeated attempts to overcome environmental damage. It is no wonder, therefore, that until recently the authorized bodies were unwilling to commit to a date to complete the first river cleanup in Israel.
Someone has finally agreed to commit to rehabilitate one of Israel's major rivers. "I have another four years left in my term," says the head of the National Water Authority, Prof. Uri Shani. "I'd deem it a failure if at the end of that time, I will not be able to proudly stroll along the banks of the Yarkon River after it has been rehabilitated."
Shani's optimism is perhaps related to the fact that there have been major efforts to clean up the Yarkon in recent months, not to mention hearings on river rehabilitation plans that at once offer comprehensive and advanced treatment of Sharon regional sewage and the diversion of a large portion of it to irrigate parks in the Dan area.
Some 50 years ago, the Yarkon lost most of the natural water flowing into it from the vicinity of the Rosh Ha'ayin wells, which was utilized by humans. Then cities in the Dan area started spilling sewage into the river and it became foul, contaminated and reeked of excrement. Today the river is divided into three segments. The eastern segment stretches from the river's sources near Rosh Ha'ayin to the hookup with an offshoot called the Kaneh River, near Hod Hasharon. This segment is defined as clean and it contains a small quantity of water that the Mekorot Water Company puts into the river.
The central segment, from Hod Hasharon to not far from the Ayalon highway, is the most polluted and contains purified waste water (sewage coming out of purification plants) from the surrounding communities that still does not meet the required standard for rehabilitating the stream. The western segment, from the Ayalon highway to the mouth of the river where it spills into the sea, is called the salty segment because of the impact of seawater that seeps into it, mostly at high tide.
Purification and spin
The basis for the cleanup efforts is the government's decision five years ago to "redeem the Yarkon." This decision stipulated that the clean segment of the stream would receive an additional quantity of fresh water for the purpose of restoration, and the remaining river areas would be restored by improving the quality of the purified sewage that flows into it. The clean water and the sewage water would be recycled: the clean water would be pumped out at the bottom of the segment from the river sources to the Kaneh River, and would be returned to it in a process known as spinning. The treated sewage would be pumped out near the Sheva Tahanot site adjacent to the Ayalon highway (the end of the second segment of the stream) and be relayed for agricultural use.
The Yarkon River Authority has been trying in recent months to promote the plan, in collaboration with neighboring cities. The Kfar Sava and Hod Hasharon municipalities have already started upgrading their joint sewage purification plant, which is a major source of treated sewage flowing into the river. According to Authority Director-General David Pergament, "the upgrade will be completed within a year and a half, and sewage water that meets the standards set by the government will then flow from the plant to the Yarkon."
After the treated sewage water leaves the purification plant, it will reach what has recently become the hit of the rehabilitation program for water sources in Israel: green basins where contaminated water is purified by natural flora. Such a basin will be set up near the meeting point of the Kaneh and the Yarkon, and will clean the sewage of contaminants that remained after the purification process at the plant.
In addition to all this, the Yarkon River Authority is setting up a pumping station for sewage that flows due into the Kaneh and is continuing to plan the spinning facilities for clean water and the purified sewage pumping station at the Sheva Tahanot site. Pergament stresses that implementing the various plans depends on funding from various sources including the local authorities that have yet to pay everything they committed to.
The limited Yarkon cleanup program could merge with the plan with broader environmental objectives prepared by engineer Ilan Halvitz. According to his plan, a network to treat sewage from the entire area will be set up in the area of the Sharon and the Yarkon. It will purify that same sewage water so it is at a standard that is suitable for uses such as restoring the river, agricultural irrigation, and municipal gardening. Sewage from Hod Hasharon, Kfar Sava and Ramat Hasharon will flow into the Eyal Reservoir north of Kfar Sava, where it will undergo additional purification treatments. From there, most of the water will flow to the Yarkon, with an additional stage of purification in the green basin near the river. At the Sheva Tahanot site, the water will be pumped out of the stream and relayed to another purification plant for the purpose of municipal gardening that is set to expand to thousands of dunams with the creation of large metropolitan parks in the Dan region.
Some of the sewage water from the Eyal Reservoir, proposes Halvitz, should flow north via a pipe that will be connected to another pipe with surplus sewage from Herzliya and Ra'anana that already is purified at other facilities. This sewage will be used to irrigate agricultural crops in the northern Sharon region, after it is also desalinated. After the irrigation, the sewage water will seep into the groundwater in the northern Sharon area, but unlike in the present situation, it will not make the water salty or pollute it with fertilizers such as nitrogen.
In the clean segment of the Yarkon, according to Halvitz's proposal, a larger quantity of fresh water will flow than that proposed in the "Yarkon redemption" plan. The Yarkon River Authority feared that such an allocation would be reduced in dry years, but Halvitz resolves this problem by pumping most of the water out at the bottom of the clean segment and reflowing it into the groundwater at a quarry located east of the Yarkon's sources.
The principle: Reusing water
The abundance of treatment plants, pipes, reservoirs and other facilities that Halvitz's plan establishes in the Dan and Sharon regions is perhaps slightly dizzying, but behind the numerous infrastructure facilities there is a simple environmental principle: reusing water for a variety of purposes, while improving its quality starting from when it first undergoes purification. "These are technologies that already exist and are functioning," explains Halvitz. "It will be possible to upgrade the treatment of sewage so that water on a par with fresh water flowing in the clean segment flows into the Yarkon." He estimates that the high cost of building the infrastructure will justify itself by the reuse of the water and the environmental benefits such as protecting groundwater from becoming salty and the rehabilitation of the Yarkon River.
The plan has the support of the Israel Nature and National Parks Protection Authority and the Yarkon River Authority, but has yet to obtain the approval of the Finance Ministry. The ministry is not interested in having the Mekorot Water Company manage such a project exclusively, but without a single agency coordinating it, it will be difficult to advance it. Finance Ministry officials declined to comment directly on Halvitz's proposals and noted that the ministry supports the implementation of the government's decision to "redeem" the Yarkon.
According to Pergament, the River Authority decided to promote the plans already approved for the river's rehabilitation, and it will do so in such a way that also enables the inclusion in the future of Halvitz's proposals. Shani says that the National Water Authority deems the Yarkon River cleanup project to be of considerable importance to residents' quality of life. He agrees that Halvitz's plan is likely to enable efficient use of fresh water and sewage water in the area, but stresses that the Yarkon River Authority must decide how to proceed. "The authority will have to take into account the cost of the rehabilitation effort, its timetable and the level of risk to the stream in every plan," says Shani. "We are offering them a range of options, including the option of using fresh water or sewage water that is of a high quality."
The National Water Authority will have to display far greater involvement in the rehabilitation plans that it has shown to date. It cannot leave the task solely in the hands of a small team from the Yarkon River Authority.
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