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La Risca Reservoir

History.

The River Moratalla is located in the central stretch of the Segura river Basin, joining it on its right bank. It is one in a series of rivers (such as the Quípar or the Argos) whose waters flow into the Segura, as opposed to the wadis on the left bank.

The reservoir is located in the municipality of Moratalla, near the village of La Risca, which is where it gets its name from.

After the catastrophic floods which the Region of Murcia suffered in the month of October 1973 the Rules of Tender began to be drafted to contract the drawing up of the “Flood Control Plan of the Segura river Basin.” In May 1977 the drafting of this “Flood Control Plan of the Segura river Basin” (F.C.P.R.S.B.) was finished.

Subsequent to the aforementioned flood, in the years of 1982, 1986 and 1987, there were further cases of burst banks and overflows which caused damage in the Segura river Basin in general and more specifically in that of the River Moratalla. This led to the enactment of Royal Decree 1/1987, of 13 November, which instigated urgent measures to repair the damage caused by the flood in the Autonomous Communities of Valencia and Murcia.
 

La Risca Reservoir Picture

It is worthy of note that amongst these last floods, that corresponding to the River Moratalla Basin during the days of the 25th and 26th of July 1986 reached a peak flood flow of 280 m³/s at its confluence with the Segura river, running 37 km downriver where it was joined by the waters of the Rambla del Judío, and 4 km below the confluence of both (Segura- Rambla del Judío), as it passed through the city of Cieza, it reached a peak flood flow of 500 m³/s.

In March 1987, the civil engineer Alfonso Botía Pantoja wrote the Study "Analysis of the canalization of the Segura river from Murcia to Guardamar" which, by limiting the flow of the Segura river to 250 m³/s, forced greater floods in some of the tributaries to the main river which had not been contemplated in the F.C.P.R.S.B.

This opinion was supported by the civil engineer José Bautista Martín in his "Report on the advisability of adding reservoirs on the River Moratalla and Rambla Salada to the Flood Control Plan of the Segura river Basin " in March 1988.

La Risca Reservoir Picture

In order to try to solve this problem of flood abatement on the River Moratalla in 1989 the “Study of alternative flood abatement solutions on the River Moratalla (Murcia)” was drafted.

This Study of Alternative Solutions proposed thirteen reservoir sites, dividing them in two large groups:

a) Reservoirs in the Upper Basin or on the River Alhárabe, which would possibly reduce their flood abatement function, whilst combining this use with that of regulation. These reservoirs were numbered from 1 to 6, with the further addition of 1-a, 1-b and 1-c.

b) Reservoirs in the Lower Basin or River Moratalla Basin, which is the name of the river after the two rivers Alhárabe and Benamor join, in which only flood abatement was studied. There were four, numbered 7 to 10.

The study performed on the thirteen potential reservoirs consisted in a comparison of solutions, taking into account hydrological, topographical, geological, geotechnical, environmental and economical factors.

As a result of this study, and on the 6th November 1990, the Directorate-General for Hydraulic Works authorized the Confederación Hidrográfica del Segura to draft the Project for the La Risca and Moratalla Reservoirs at their respective sites denominated 1-b and 9, in accordance with the “Study of alternative flood abatement solutions on the River Moratalla”.

In November 1990 the Chief Engineer for Hydraulic Infrastructures of the Confederación Hidrográfica del Segura, José Bautista Martín, drafted the Rules of Tender for the contracts for the technical studies of the Reservoirs on the River Moratalla at sites 1-b and 9, drafting the project corresponding to site 1-b, which from then onwards became known as the La Risca Reservoir.

La Risca Reservoir Picture

This Project for the La Risca Reservoir served as the basis for the public tender for the works on the dam, included in the works carried out as part of the Flood Control Plan of the Segura river Basin.

On the 29th December 1996 the Variation Order was signed and the works began thereafter.

Due to certain events during construction it was deemed necessary to produce a works amendment project in order to make a series of changes to the existing project which consisted in:

1.- Modification of the energy dissipation mechanisms.
2.- Modification of the right abutment.
3.- Changes in the project’s measurements.

On 29th April 1998 a report was drafted by Carlos Marco García, Head Engineer for the works, on the possible potential risks which could be caused by stopping the construction work because of the drafting of the proposed amendment. As a result, a technical proposal was drafted stating and evaluating the actions and measures needed to guarantee the safety of the works.

On 12th February 1999 the Directorate-General for Hydraulic Works authorized the drafting of Amendment I to the Project for the Construction of the La Risca Reservoir, which was technically and finally approved on the 8th September 2000.

On 25th September 2001 authorization was requested from the Directorate-General for Hydraulic Works to draft the Project for Additional Works I, and on the 19th October of the same year the Directorate-General awarded the drafting of the Project for Additional Works for Roads and Accesses, Drainage and Environmental and Landscape Integration of the Project for the La Risca Reservoir, Municipality of Moratalla (Murcia).

The works ended on the 20th of October of 2002.

La Risca Reservoir Picture

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