In my country (Iran), almost on all rivers have construct large and small dams. Which has not only solved the country's water problems, but also exacerbated it. The obvious example is Urmia Lake, which is almost have dried. The drying of other wetlands has also caused dust storms. The protest against the allocation of water resources in some cities has led to a clash with the police. The construction of these dams has been costly to the government. But today it seems their absence is better than being.
What do you think? I will be glad to see your comments.
There is huge body of literature about the socio-environmental impacts of dams, most of them occurring in the middle and long term. From my point of view, dam constructing is an obsolete idea. In contrast, there are pretty good examples of the benefits of "undamming". See Bendnarek, 2001
Hello Amin,
I believe dams create rather than solve water and socio-ecological problems. In simple terms, dams constructing is a multibillion dollar business which financially benefits the investors (multinational conglomerates and banking institutions) and which brings no short nor longterm benefits to man & his environment.
Environmentally, about 99% of all dams lack fish ladders stopping many fish from moving upstream to their natural breeding grounds because of a blockade in migration paths. This results to an ecological prevention of the reproductive cycle, hence slowing down or sometimes disrupting the breeding cycles.
Recently, several dams have collapsed such as the Gusau Dam of Zamfara State, Nigeria which collapsed on 30th September, 2006. This collapse killed more than 40 people and hundreds of livestock, destroyed over 500 homes, farmlands and displaced over 1000 people.
In August 2012, the Maga Dike along the banks of the river Benue in north Cameroon collapsed, killing more than 1000 people while rendering thousands of others homeless.
Here in Cyprus we have been builing dams for the last decades. In a semi arid country like Cyprus, damming the rivers seemed the only solution for irrigation and households. Today all of our main rivers have dams constructed in their catchment and although one might say that this has saved the day for the locals, it has been devestatng for the environment 100%. All river courses downstream dams are dry, habitats, especially riparian habitats, have been totally altered, groundwater in coastal areas is suffering from sea intrusion, fish cannot travel upstream or downstream, lack of sedimentatoin in river outflows causes coastal erosion problems and minimum nutrient enrichment in coastal habitats thus affecting primary productivity in the marine environment, etc.
Yours is a general question requireing very careful state and site-specific analyses and documentation. Are dams all that bad in Greece? for example...
Dams, wrongly-siteed ones, do provide terrible stories of destruction and degradation for river biodiversity. Also many ecosystem services related to free-running rivers have been lost. Many disservices created in artificial dam reservoirs have proliferated. In some cases small dams are good. Good for societies, local communities, local economies and agriculture. In a few (very few) cases dams also provide reservoirs that mimic natural conditions on river floodplains and these are now important wildlife refuges (these are usually very low weir-like dams, such as our Lake Kerkini - famous for its birds). In some cases small dams are improtant for wildlife on very arid islets/islands where natural spring waters and natural wetlands have all but vanished. So this is not an easy question to answer. Many thanks for posing the question.
Dear amin,
This vast construction of dams is due to Iran's geographical situation. Water of the rivers in Iran mostly exit Iran and goes away. So in order to control this amount of water leaving the country it is necessary to build dams. Of course there are a lot of considerations to make before a dam is built. So generally we cannot say whether building a dam does more harm than being useful.
About the Urmia Lake I must emphasis that building dams had nothing to do with it. It is because of the uncontrolled and illegal deposition of water from underground sources. The total storage of the dams built upstream of the lake is about 2 billion cubic meters whilst the evaporation causes this lake to lose about 3 billion cubic meters of water per year. This is a common belief and not totally right idea that these constructions has caused the lake to dry up.
Dams (water storage systems)serves many purposes such as irrigation, water supply, hydro-power, flood control, fisheries, recreation etc. But it is not free of environmental problems as you mentioned. Further, construction of dams are generally expensive.
Dam constructors should analyse all those issues from the stage of planning and design of dams. That will helpful to increase the benefits and minimize the damages.
In my opinion, the dams (storm water storage systems) are essential for countries where the rainfall is seasonal (concentrated to monsoon periods) in order to meet the demand which is relatively constant throughout the year.The countries like mine (Sri Lanka) cannot survive without dams. It is witnessed by construction of dams throughout our history (for nearly 2500 years) for the purpose of irrigation and water supply. Some of the dams constructed in early stages of our civilization are still in operation.
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