Vorlage:Infobox lake Lake Qaraoun located in the southern region of the Beqaa Valley, Lebanon is an artificial lake or reservoir created by building a 61 m high Concrete Faced Rockfill Dam (the largest dam in Lebanon) in the middle reaches of the Litani River (longest river in Lebabon),near Qaraoun village, in the year 1979. The reservoir created by the dam provides multipurpose benefits of Hydropower generation (190 MW), irrigation (27,500 ha) and domestic water supply.[1][2]
The annual surface water flow of 420 MCM in the Litani River received at the Lake Qaraoun is utilised for generating hydroelectric power of 600 Gwh at three hydroelectric power stations at Markaba, Awali and Jun with total installed capacity of 190 MW. During the dry season, 30 MCM of water is diverted from Markaba power station to meet the needs of the Kassmieh irrigation project.[3]
The lake is home for 20,000 odd migratory birds which visit annually.[2]
Geography
The upper Litani River where the artificial lake or reservoir has been created with the dam at elevation of about 800 m is in the inland region of Beka Valley whose elevation range generally lies between 650 m and 1600m, with mountain peaks raising as high as 3090 m.[3]
The Litani River drains the southern end of the Bekaa Valley plains (a continuation of the Great Rift Valley), crossing the southern periphery of the Mount Lebanon range and discharging into the sea north of Tyre, after traversing a length of 170 km entirely in Lebanon.The hydrographic system of Lebanon consisting of 40 major streams is typecast into five regions, which includes the Litani River Basin formed by the Litani River in its eastern and southern part, with the river debouching into the sea at the southwestern end. The basin has a total catchment area of 2120 sqkm, which forms 20% area of the country, with about 1600 sqkm intercepted at the Lake Qaraoun by the El Wauroun Dam for proviiding mulpipurpose benefits.[3][4] The artificial lake is created across the Litani River in its middle reaches. Litani River is the longest river in Lebanon at the southern end of the Bekaa valley.[1][2][3][5]
The Litani River, which lies entirely within the territory of Lebanon rises near the historic city of Baalbeck (now site hardly discernible due to high rate of water extraction in this reach for pumping and ancient city development) and flows through. It is one of the 40 major streams in Lebanon and is the longest from the source to the Mediterranean sea.[3]
Climate
The climate in the catchment of the reservoir is of continental type with 90% of rainfall occurring between November and April, with January experiencing the maximum precipitation. Snow fall is also experienced at elevation above 1500m. The rain fall incidence in the Beka Valley, which widely varies spatially and temporally, is an annual average of 1500 mm in the mountainous region of the upper valley to a low of 700 mm in the south in the coastal region. However, the average rainfall is 800 mm/year in the catchment area of about 1,600 km2 at the reservoir carted at the dam.[3]
According to water balance studies carried out for the Litani River, the total inflow of the river at the reservoir location has been assessed as 1,280 MCM per year, of which 60% is accounted towards aquifer recharge and evapotranspiration. Of the balance 500 MCM year of surface water, 80 MCM per year is used for various uses by pumping before the flow reaches the dam. Thus, the flow of 420 MCM is available at the reservoir, in an average year (35-year average flows from 1920s). However, in drought years, the flow could reach a low of 320 MCM (recorded in 1972–73). Based on precipitation data, the total annual flow could be as high as 700 MCM. The average annual flow of 420 MCM received at the reservoir is utilised through the dam created at the site and diverting it through a series of tunnels and ponds to generate 600 GWh of energy at three hydroelectric power stations (90 MW total installed capacity) located at Markaba, Awali and Jun. It is also utilised for providing irrigation benefits by diverting 30 MCM per year of water from a channel of the Markaba power station for the Kassmieh Irrigation Project.[3]
Reservoir
The Qauroun reservoir or lake created by the El Wauroun Dam on the Litani River has a water spread area of 11 sqkm. It is the largest artificial lake in Lebanon, located in the southern part of the fertile Bekaa Valley has a total capacity of about 220 MCM and effective storage (live storage) of 160 MCM. Apart from power generation as a primary benefit, which meets about 7-10% of power requirements of Lebanon, the stored waters also provide irrigation benefits with flows of 140 MCM (110 MCM is used in South Lebanon and 30 MCM in Bekaa) while 20 MCM is used for domestic water supply in the Southren Lebanon. Controlled reservoir operation also provides flood control benefits and prevention of water logging in an area of about 1500ha.[3][4]
During 1999-2000, the water quality of the reservoir has been investigated from 16 samplin points on the river and its tributaries, by the Ministry of Environment and the Litani River Authority as an part of an exercise to evolve management plan for the Litani River and Lake Qaroun's catchment. It has been noted that seven sewer networks drain directly into the river. Untreated sewerage from the towns of Baalbek, Houch el Rafqa, Qaa er Rim, Zahle, Chtoura, Qabb Elias, Bar Elias, Joub Jannine and Qaraoun flow into the Litani River or its tributaries, apart from industrial effluents many factories related to manufacture of sugar, paper, lead, limestone crushers, agro-industries and also from poultry farms, tanneries and slaughterhouses.[5]
Dam
The dam, which holds back Lebanon's longest river, is 61 m high and -- m long. A gallery of 6,503 meters carries the water to the underground hydroelectric station where transformers produce a maximum of 190 megawatts. Future plans will allow the dam to irrigate 310 km2 of farmland in South Lebanon and another 80 km2 in the Beqaa Valley. Qaraoun lies on the east of the lake and Aitanite on the west.
Tourists and visitors visit the lake where fishing and water sports, such as water and jet skiing as well as sailing are popular activities. Fish-serving restaurants on the lakeside are popular destinations during the summer.
References
- ↑ a b Qaraoun Village. aub.edu.lb, abgerufen am 23. April 2011.
- ↑ a b c Lake Qaraoun. Birdlife.org, abgerufen am 24. April 2011.
- ↑ a b c d e f g h Chapter 2. Assessing Lebanon’s Water Balance. International Development Research Centre (idrc), abgerufen am 25. April 2011.
- ↑ a b Lebanon. Aquasta:Fao.org, abgerufen am 26. April 2011.
- ↑ a b Lebanon State of the Environment Report. (pdf) Ministry of Environment, Government of Lebanon, abgerufen am 25. April 2011.