The State of Israel is a long narrow country not only where its political borders are concerned but also with respect to its hydrological boundaries. The Mediterranean Sea in the west and the Jordan River in the east constitute the base levels for the drainage of Israel’s rivers and streams with the exception of the Arava basin, which drains into the Eilat Bay. The watershed in the Judean Hills, Samaria and the mountains of the Galilee are located more or less in the middle of the country, and consequently, the State of Israel has an abundance of short rivers and streams with small catchment basins, at least when compared with the rivers of Europe and America.
These rivers and streams were created over a period of tens of thousands of years as rain fell over the Judean Hills and Samaria, the Shefela (inland plain) and the coastal plain, and they flowed to the drainage base levels, that is into the Mediterranean Sea. The coastal rivers and streams which drain the mountains of Samaria were created during the Neogenic era and even during the Pleistocene epoch. According to how the geological time periods are defined, the Neogenic era began some 25 million years ago. The rainfall together with weathering and erosion created the natural layout with which we are familiar nowadays. Flooding occurred mostly in flat regions such as the coastal plain, and the fauna and flora adapted to the landscape units and habitats that evolved over time. In other words, the ecosystem created was subject to natural disturbances with no influence exerted by humans.
Twenty-one (21) rivers and streams empty into the Mediterranean Sea between Rosh HaNikra and Rafah on the Egyptian border; some of these are perennial while others are seasonal streams. Sections of two rivers, namely the Yarqon and the Taninim River are fed by springs which are in fact effluxes of the Yarqon-Taninim aquifer. The remaining rivers and streams are fed in part by permanent or seasonal springs and all carry runoff water in winter. The majority of the rivers and streams are polluted by sanitary and industrial wastewater on various levels.
The nature of the catchment areas was the principal factor in human activities in Israel in general and in the coastal plain in particular facilitating settlement over thousands of years. A glance at the location of the cities on a map of the territory of the tribe of Dan, as stated in the Book of Joshua, Chapter XIX shows that these were situated where the danger of their inundation by the water flowing in the rivers and streams was slight, if at all possible. When the Jews began to arrive on the shores of Israel they naturally headed for those areas which were unoccupied or regions where considerable efforts had to be made to prepare the land for settlement – coastal plain and interior valleys. This settlement led to the initial clash between the rivers and human activity, as these activities were not adjusted to suit the reigning forces of nature and on many occasions, they worked against them.
First among the problems noted above was the very fact that large population concentrations were located in flat regions, which suffered from drainage problems owing to the geomorphology of the coastal plain and the interior valleys. In ancient times many water projects were built here to utilize the potential energy from the flowing water but they required the construction of weirs to create the differences in elevation needed to produce water power. In most instances, no cities were established adjoining the water installations but were located at a distance from them where the surface’s elevation was high enough to avoid the risk of flooding. The ancient Romans worked to solve the drainage problems of the Poleg River by creating artificial trenches to drain the water.
The division of Israel into administrative units also failed to take the natural units into account, that is to say, drainage basins. The catchment areas were divided up and in many cases, the rivers and streams marked the borders between the various authorities.
The current state of the rivers and streams reflects this disregard for their natural physical needs. Facts on the ground have been established that result in a conflict between human activity and nature’s needs, and we now find ourselves in a situation whereby we have to manage natural resources without control, even partially, over the one factor which is their principal driving force, namely rain.
Similarly to all the other rivers, the Yarqon is a product of natural forces, the result of thousands of years of rainfall and water flows, which cut outflow channels as they made their way to the drainage base level by the sea. The Yarqon River constitutes a defined hydrological unit, whose processes are dynamic, ongoing to this very day and everlasting. What makes the difference nowadays is that we see the river “as it is evolving” and can understand that our actions constitute a form of intervention, which leaves its mostly negative mark on the process and on ourselves.
The Yarqon River drains an area extending from the national water divide in the Judean Hills and Samaria to the Mediterranean Sea, covering an area of 1,800 km2. Most of the river’s tributaries, drainage channels, flow off the mountain and pass through the Shefela (inland plain) and the coastal plain. The flat area accounts for about 25% of the overall catchment basin, the area is drained by a system of tributaries and includes intensive human activity related to agriculture, settlement as well as the associated work. When it comes to the volume of water flowing in the Yarqon River this is the second largest quantity among Israel’s rivers exceeded only by the River Jordan. The area of the catchment basin in the Yarqon River is the third largest in the country and is surpassed only by the Besor and Jordan Rivers.
The catchment basin is also divided by man-made boundaries; an administrative division by the international border dated to 1967; division between local authorities and local planning committees, between the planning districts of the Ministry of the Interior, and between many additional interested parties such as the Israel National Roads Company (formerly the department of public works – MA’ATZ), Israel Railways, Israel Electric Corporation, Netivei Ayalon (Ayalon Highway), Cross-Israel Highway (Route 6), Dan Regional Association for Environmental Infrastructure, EAPC – Eilat-Ashkelon Pipeline Co. Ltd., and similar. The different areas of responsibility of government ministries and authorities have also led to a further distribution of authority within the catchment basin, as these activities have implications for the processes occurring in the catchment basin. The government bodies concerned include the Ministry of Environmental Protection, Ministry of Agriculture and Rural Development, Ministry of the Interior, Ministry of Energy and Water Resources, Ministry of Health, Ministry of Transport and Road Safety, Drainage Authority, Israel Nature and Parks Authority and the River Authority. The Yarqon River Authority is a statutory body established in 1988 under the Streams and Springs Authorities Law. The Authority incorporates different public bodies with an interest in the river and its environs. The government departments, which are members of the Authority, include the Ministry of Environmental Protection, which is the ministry in charge of the River Authority, in addition to the Ministries of Agriculture, Interior, Health, Tourism as well as the Israel Land Administration and the Israel Government Tourist Corporation. Seven local authorities through whose territory the river passes are also represented and they are Tel Aviv, Ramat Gan, Bnei Brak, Petah Tikva, Ramat HaSharon, Hod HaSharon, and the South Sharon regional council. Additional bodies represented in the River Authority include the Israel Nature and Parks Authority, KKL (Keren Kayemet LeIsrael), Dan Regional Association for Environmental Infrastructure and the Mekorot Water Company.
Most of those concerned with the rehabilitation of rivers worldwide proceed in their work after learning about the limitations arising from past deeds and following a re-appraisal of the needs of the river and mankind in both the present and future. This new understanding is expressed in multidisciplinary plans, which include elements of hydrology and hydraulics, ecology, environmental quality, leisure activities and development needs. The rehabilitation process must be implemented by an organization, which has an understanding of the issues and is capable of making progress despite the existing obvious conflicts of interest.
At this stage, it is evident that the concept of the “Yarqon’s needs” is no longer simple and explicit but must be updated in line with the prevailing limitations. This approach is correct not only for different specified rivers but is also true for different sections of the same river.
Human activities take place in the Yarqon’s catchment basin in a way that leads to a reciprocal influence between the river and mankind.
This influence is mostly negative and becomes a major factor in the system. This situation may be demonstrated in four areas:
- Flooding: The size of the channel at each point along the river is determined mainly by the quantities of water which cut into it in the past and the frequency at which these flow rates rushed along. In cases where the flow rate is above average and the flow cross-section is too small to contain all the water then the adjoining areas will be flooded. The extent of the flooded areas, the floodplain, depends on the elevation above sea level and the topography. Building in areas within the floodplain exposes those buildings to flooding at the same frequency at which these occur. Alternatively, protecting the structure against flooding by reducing the size of the floodplain does not make the flood waters disappear but rather they then flood other areas, usually upstream in the river or on the opposite bank.
- Diverting the water sources: In our region with its meager water resources, every such source contributes to the potential water supply available to the state, including the springs, which feed the rivers. Pumping out the groundwater and trapping the water from the Yarqon’s springs reduced the flow in the Yarqon and caused far-reaching changes, even drying it up.
- Pollution: Pollution sources can be divided into two types: Point sources and non-point sources. The first type includes wastewater treatment plants and diverse outfalls from factories. The second type, non-point sources, includes surface groundwater from urban areas and agricultural fields, and on smaller scale factories, parking lots and similar elements. Non-point sources do not flow consistently but are rather the result of rain or faults in the wastewater piping system and the wastewater treatment. Surface groundwater is produced quickly when it rains over urban areas and therefore the first rains of the year wash pesticides and fertilizer, oils and fuel, heavy metals, garbage, bacteria and other materials into the Yarqon River. Moreover, most of these materials flow into the river when it is in a highly sensitive state immediately after the summer season when almost no water flows along the channel. Although the agricultural fields can contribute their share of the pollution later than the urban areas, their potential pollution is nevertheless significant and includes chemical materials and sediment.
Combination of factors: The accumulated implications of the processes exert a negative influence on how the river functions as a drainage route and as an ecosystem with a wide range of habitats as well as suitable fauna and flora. The river lacks sufficient good water because we drink that water, and yet polluted water and sources of pollution of various kinds prevail because we have neglected methods for preventing pollution and consequently, frequent flooding is a direct result of our infringing on the river’s domain and thereby increasing the size of the areas contributing ground water. In this way, human actions have changed the Yarqon from a resource into a hygienic and environmental menace affecting an extensive area and wasting its considerable potential.