Water & Irrigation
Juan G. R. The Guadalquivir river needs channel correction and drainage works against floods
Alicante, 22/12/2010, Spain.
During different months of 2010, heavy rains have affected the Guadalquivir river basin in the Community of Andalucia at Spain and have provoked affectation of major agricultural and urban areas as a result of excessive water. Many flooded agricultural and urban areas have been affected more than 5 times during this year, that is a problem, so it is essential to rectify a portion of the river channel to reduce the impact of large floods, protect some areas with protection dikes, diversions for carrying water from areas with sufficient water resources to other regions with water shortage, clean the river channel, increase agricultural and urban drainage, but all necessary hydraulic works are expensive, their implementation is justified because the losses caused by flooding are more higher than the cost of implementation and operation of new hydraulic works.
The floods and economic effects on human and material assets of the Guadalquivir basin dating back over 500 years, its are happening before the discovery of America, which have caused economic losses accumulated billions of euros in damage to agriculture and property in urban areas and the irreparable loss of human lives. The Guadalquivir River Basin occupies an area of 63,085 km2 and has a water reservoir capacity of 8283 hm 3, with a volume of water stored in 6875 hm3 at December 21, 2010, which represents 83% of reservoir capacity. The entry into Spain of different shocks and cold fronts during the winter period of 2010, which has been accompanied by heavy rainfall has caused severe flooding in rural and agricultural areas of the country, affecting more strongly the provinces of Seville, Cordoba and Jaen in the Andalusia region, the accumulated rainfall in the month of February for the Community of Andalusia are above 250 liters per m2, which doubled precipitation in Spain for that month. In March, again boiled over several tributaries of the Guadalquivir, where more than 1,500 people fled their homes as a result of increased flow of the Guadalquivir River, which on 6 March, 2010 reached a volume of 2000 m3 / seconds in Cordoba and 2700 m3/sec. in Seville, below that recorded in this river in Seville in the flood of 1963 with a value of 6000m3/seg. Again during the period from 7 to 17 August 2010 flooding occurs in Jaen, Cordoba and Seville, and this time three people die in Cordoba as a result of heavy rains. Again during the month of December have been three floods and precipitation affect ruthlessly to the provinces of Jaen, Cordoba and Seville. Rainfall for the period January to December, are considered high with values above 30% the annual average of the current decade, with significant equity in the period 2001-2010.
In the regions most affected by the floods, the volume of low and medium reservoirs delivery capacity are near to maximum capacity, not the large dams still allowed to retain much more water, but it has been strategic to empty several reservoirs , which shows that it is necessary to build more reservoirs to enable further soften the impact of floods and to retain more water in rainy periods, to cope with the demand for water during periods of intense drought. It is also advisable to correct part of the river channel and it flow to reduce the impact of large floods, to protect some areas with protection dykes, clean the channels and have derivative works that lead the water from areas with sufficient water resources to other regions water deficit, although this set of hydraulic works are expensive, their implementation is justified because the losses caused by flooding are much higher than the cost of implementation and operation of new hydraulic works. The execution of these works is strategic, demand strong hydraulic and financial support from Central Government, the Regional Government and the European Union.
It is essential to increase the capacity of networks of internal and external drainage in many cities and agricultural areas in order to reduce the large economic losses and human lives that cause these unfortunate events. The flooding problem becomes more critical if we take into consideration, inadequate urban planning has allowed to construct buildings, homes and businesses in low lying areas and former water course without having completed the recommended protective works to counteract the effect of flooding, which causes the damage is even greater. There are many roads that don’t have an adequate hydrological study, so it is necessary to increase the number of drainage works, to protect them from the effect of floods, often act as road dyke increasing the time of the flood affected areas. Proper planning of steps and a proper investment plan on flood control will possibility that the material damage and human losses will be considerably reduced.