Dr. Assaf Rosenthal
Direct link to this page: https://www.hayadan.org.il/rosentaldamms.html
Of the larger, more expensive, more complicated and well-known construction enterprises and at the same time the ones that have a greater impact on their environment. I do not intend to review their virtues and the exploits of their builders, on the contrary, I will bring a number of examples of large dams that caused enormous and irreversible damage to their environment.
In China, one of the dams is being built which, when completed, will be one of the largest in the world. The dam, known as the Three Rivers Dam, is located at the place where two rivers join the Ying-tse River, which is one of the longest rivers in the world. The entire area is known for its special and beautiful scenery. The lake will cover one of the most beautiful landscapes in China, important archeological sites, and of course what was home to millions of Shifuno residents. Among other things, the opponents of the dam claim that it will be a weak point at which sabotage attempts by the opponents of the regime will be aimed. Tampering with the dam after its construction will cause floods that will inundate urban areas, meaning a fatal injury to millions of people.
The Glen Dam was built in a canyon on the Colorado River, initially the green bodies opposed the construction of the dam and after a while they removed their opposition? Today, the person who chaired the "Sierra" club claims that the removal of the resistance was the biggest mistake of his life! Because of the dam, the seasonal floods do not clean the sand from the sides of the canyon, which causes the infiltration of invasive plant species, which results in damage to the local animals, following a repeated appeal by the Sierra Club, they allow the opening of the dam during the flood season and the situation returns to normal.
In Laos, they are planning to build a dam without a comprehensive survey on the environmental damage and while leaving about seven thousand people free. Kariba Dam was built in Zimbabwe on the Zambezi, the dam created a huge lake, from which about sixty thousand people were evacuated in the so-called "Operation Noah". The inability to control the amount of water during the rainy season causes deadly floods down the river in Mozambique every year. A new dam built on the Nile raises many concerns The dam built under the name of Marua-Hambada is located on the Nile in Sudan north of Khartoum. The intention of the builders is to provide about fifty percent of the electricity consumption in Sudan, but, during the construction of the dam, about fifty thousand farmers will be evicted from their land, special and unique archaeological and prehistoric sites will be flooded. The green bodies in the world see the Sudanese government's behavior in planning the dam as a test of the government's intention to govern fairly and considerate of the subjects.
There are many reasons for the drying up of Lake Chad, most of them due to human activities. Now it turns out that a significant part is due to the dam that was built up the Dejaya River. The river water was diverted into two canals to allow irrigation of agricultural areas. Every rainy season the canals overflow and flood areas and houses and a lot of damage is caused, however, the river water does not reach its natural destination: Lake Chad.
The most familiar and known of all the dams (at least in our immediate vicinity) is undoubtedly the Aswan Dam. The need for a dam arose because of the large population and the demand for electricity on the one hand, and also because of the settlement of new farmers in the Nile Delta in flood-prone areas. The planners of the dam thought to regulate the flow in the river and thus prevent the damages of the floods. The first dam was completed in 1902 and was immediately found to be insufficient, so it was raised twice, when, despite the elevations, it became clear that the dam was not fulfilling its role, it was decided to build a large dam up the river. The new dam completed in 1970 created a huge lake that covered important archaeological sites. If a rescue operation had not been carried out, the lake would have covered one of the most beautiful and important archaeological treasures in the world: the temples of Abu Simbel were saved by UNESCO with the budgeting of many bodies.
The Abu Simbel temple was saved, but the dam provides only a third of the amount of electricity it was supposed to provide, according to expectations, this is due to the deposition of alluvial sediments in the lake, alluvium that raises the water level and damages the turbines, the flood regime in the Nile Delta is interrupted and the nutritious clay does not reach the agricultural fields. Since the floods are controlled, there is no supply of sand to the eastern part of the Mediterranean and the lack can be seen on our shores. Due to a lack of supply of clay, the northern part of the Nile Delta is sinking and seawater entering the system causes wells to be salted and in the next step to the sinking of buildings and the flooding of brackish lakes in the vicinity of the delta that supplied a large part of Egypt's fish consumption. The fish of the eastern Mediterranean received food enrichment by the Nile floods, there are no floods and the fish population is decreasing. On the shores of the created lake - Lake Nasser, thick vegetation grows, which is a breeding ground for the release of bilharzia-carrying bacteria and the increase in intestinal disease is significant.
A new dam that is causing a lot of opposition is the Bojagali Dam planned to be built on the Nile after leaving Lake Victoria. According to a survey in East Africa, it turns out that: dams built to generate electricity as well as to distribute water in dry areas cause a significant threat to the variety of aquatic species in the water bodies, and also, despite the intentions to divert water for use by the population in dry areas, the residents in the areas where the dams are built are harmed. The damage is manifested in the need to evacuate living areas, and in the danger of flooding in areas adjacent to the construction of the dams. Despite the attempts of official bodies to reduce dependence on hydro-electric facilities, there is still room for improvement by increasing the use of gas stations and more so in thermo-geological facilities, meaning the utilization of geysers and hot springs along the African depression.
Salmon and eels are unable to complete their life cycle because of dams. Both species divide their lives between the oceans and the rivers, the dams in the rivers prevent them from going up the river and the result is that all over the world there is a decrease of about thirty percent in their populations. Considering the fact that both species are considered a sought-after delicacy all over the world, this is a serious blow to the fishing economy in many countries
More than half of the world's largest rivers are dammed. Precipitation does not reach the mouths of the dammed rivers and this causes accelerated weathering of large areas in the lagoons and water bodies located in the mouths of the rivers.
In November 2000, a sub-committee on dams of the World Bank met. Together with the World Conservation Organization, to evaluate the advantages and disadvantages of dams in the last row, the participants write that: "The tested dams produce less electricity, provide irrigation water to small areas and less drinking water than expected in the planning."
Of course, there are many advantages to many dams, but as always, you should always perfect the advantages against the disadvantages and the damage, when the principle of open and sustainable should be at the foundation of the planning. That is, after all the inspection, one should know that hydroelectric stations are one of the cleaner means of generating electricity and therefore positive for the environment, only that when building dams and stations one must learn from the mistakes of the past, calculate all the environmental consequences and build so that the dam does not harm the environment and the local population, meaning again: wild development Kima!
A compilation of Dr. Assaf Rosenthal's articles on the Hidan site
https://www.hayadan.org.il/BuildaGate4/general2/data_card.php?Cat=~~~162681187~~~218&SiteName=hayadan
