Moratalla Reservoir
Background
Overview:
As a result of the the catastrophic floods in the Murcia Region in October 1973, Tender Specifications for the drafting of the “General Flood Defense Plan in the Segura Basin”were issued. This document was drafted on November 24, 1974 and approved on December 9 of the same year.
The tender on technical assistance for the execution of the works was published in the Official State Gazette on January 10, 1975, and the contract was awarded to AHINCO S.A. by Ministerial Ordinance dated July 11, 1975. In May 1977, the aforementioned draft of the "General Flood Defense Plan in the Segura basin"(P.G.D.A.) was finished.
After the 1973 flood, during 1982, 1986 and 1987, more floods caused important overflows and damages in the Segura basin in general and, in particular, in the Moratalla river basin. This prompted the enactment of Royal Decree 1/1987, dated November 13, through which the necessary measures to recover the flood damages in the Autonomous Community of Valencia and in the Region of Murcia were adopted.
It must be pointed out that the Moratalla river basin, on July 25 and 26, 1986, had a maximum flow rate of 280 m³/s in its confluence with the Segura, continuing 37 km downstream, where the Judío watercourse emptied into it, and reaching a peak flow rate of 500 m³/s as it crossed through the town of Cieza, 4 km downstream from where the two rivers join (Segura-Rambla del Judío).
Rise upstream from the Moratalla dam.
The Moratalla Dam Project, approved by the General Directorate of Hydraulic Works on June 23, 1993, was publicly announced in the Official State Gazette of the Murcia Province on November 19, 1993, and the Environmental Impact Statement was issued by the General Directorate of Environmental Policy through a resolution dated April 24, 1995.
This project was the basis for the Resolution published by the General Directorate of Environmental Policy in the BOE nº 119, dated May 19, 1995, calling for tender for the dam works as part of the actions carried out by General Flood Defense Plan of the Segura basin.
The Construction Project was approved by a resolution issued by the General Directorate of Hydraulic Works and Water Quality on July 26, 1996, and the contract subscribed on May 20, 1999, with a deadline of 20 months from the day after the document verifying readiness for construction was subscribed, which took place on June 18, 1999.
Modified project:
On October 18, 2000, the General Directorate of Hydraulic Works and Water Quality of the Ministry of the Environment authorized the drafting of Modification Nº1 to the Works in the terms requested, and proceeded to the temporary suspension of the works.
The Temporary Suspension document was executed on November 7, 2000.
In compliance with the aforementioned Authorization, the “Modified Project Nº1 for the Moratalla dam, Moratalla municipality, MURCIA” was drafted in November 2000.
Finally, on May 19, 2000, the Moratalla dam was rated A according to potential risk which could arise from breakage or malfunction.
Dam crest.
Supplementary project:
Subsequently, on September 12, 2001, authorization was requested to draft the Moratalla Dam Supplementary Works Project Nº1, which involved works downstream from the dam.
In May 2004, the provisional completion of the dam works took place.
Spilling basin.
Access
The access to the prey from Murcia realizes across the highway A-30 Murcia - Madrid, connecting with the sale of the Olive tree. From this point it is continued up to Calasparra by the road C-3314, with a tour of 24 km. From this locality there takes the road MU-510 that Calasparra connects with the road C-3211, being to 4 km the beginning of the approach road to the closed one.
The above mentioned access borders on the zone of the river, ascending then up to the skirt of the calcareous sting of an insect of the right margen to end up by connecting with the coronation of the dam for his margin right, after crossing a length of 1140 m.
Another possible access from Murcia realizes by means of the highway that it joins the capital with Caravaca. Just before coming to the above mentioned population the detour has to take towards Calasparra. From this population the itinerary to continuing coincides with the explicitado previously.
it is possible to accede to the approach road to the dam from the road C-3211, which joins the populations of Socovos and Moratalla, continuing for the MU-510.
The location of the reservoir can be seen in the following map:
Characteristics
| DAM SITUATION | |
|---|---|
|
Province
|
Murcia |
|
Municipal territory
|
Moratalla |
|
River
|
Moratalla |
|
Hydrographic basin
|
Segura |
|
BASIN DATA
|
|
|
Surface of the hydrographic basin of the Moratalla river
|
328.56 kmm² |
|
Origin height of the Moratalla river
|
1,450.0 m |
|
RESERVOIR DATA
|
|
|
Surface of the reservoir at the Project Flood Level (NAP)
|
3.01 ha |
|
Volume at NAP
|
8.07 hm³ |
|
NAP height
|
346.88 m |
|
DAM BODY
|
|
|---|---|
|
Type
|
Gravity |
|
Top height
|
606.3 m |
|
Total dam height from the foundations to the top
|
43.8 m |
|
Top length
|
165.00 m |
|
Top width
|
6.5 m |
|
CHUTE
|
|
|
Total number of chutes
|
1 |
|
Profile
|
Creager |
|
Adjustment
|
Fixed lip |
Underwater dam wasteway.
Purpose
The exclusive purpose of the Moratalla dam is to laminate the floods of the basin, characterised by a high intensity of rainfalls with a short concentration time.
Through such a work, it is reduced the flow peak circulating by the Segura river after the mouth of the Moratalla river into it.
Underwater wasteway
Territorial and Administrative Context
Physical characteristics of a basin.
The Moratalla river is an affluent of the right margin of the Segura river, and it is the object of a toponymic dichotomy in the National Geographic Institute Official Maps, where it appears, interchangeably, under both the names of Benamor and Moratalla
According the people of the area, and confirmed by the 1982 edition of the Regional Map of the Autonomous Community of Murcia which contains the actual toponymy of the hydrographic network, the Motaralla is called Alhárabe river from its source to the confluence with its main tributary on the right margin, which is the Benamor river. This confluence takes place approximately 5 km downstream, near the site known as El Cobo.
The Moratalla river is born 1,450 meters above sea level at the foothills of the Arcaboche Mountains with the name Alhárabe. After flowing for 50 km, it empties into the Segura river at a place known as La Esperanza, close to the Sanctuary of the Virgin of the same name, patron saint of Calasparra. By the time the two rivers join, the Segura has traveled a distance of 170.5 km from its source, and it rises 273 m a.s.l., while the average slope of the Moratalla river along its course is 2.4%.
The Moratalla river basin by its mouth is 345 km², while at the Moratalla dam enclosure, it becomes 328.56 km², of which 76.8 km² belong to the sub-basin of the La Risca dam, upstream from the Moratalla dam.
Watercourse upstream from the dam
Environmental information.
It must be noted that the environmental factor had a decisive influence over the decision taken by the Survey of alternative locations for the dam prior to drafting the project, because of the environmental advantages of its basin over other options.
Annex Nº12 of the Building Project is the Environmental Impact Assessment, which includes the necessary measures to minimize or eliminate the environmental impact of the construction of the dam and its presence over the watercourse.
The results of the study did not reveal any high risk, parameter value or impact indicator requiring corrective o minimizing measures.
The measures adopted in the project's Environmental Impact Assessment to eliminate or reduce the detected alterations are briefly listed below:
- Reconstruction of roads and access, as well as the construction of paths
- Protective and corrective actions for the slopes.
- Reforestation of the affected areas.
- Conservation and improvement of wildlife in the affected areas.
- Compensatory measures to the affected population.
- Landscape integration of degraded areas.
- Establishment of a Surveillance and Control Plan to monitor the effectiveness of the measures adopted and the possibility of introducing new ones in case of additional alterations that have not been previously detected.
Through a resolution dated April 24, 1995, the General Directorate of Environmental Policy (DGPA in Spanish) submitted the Environmental Impact Statement (DIA in Spanish), listing a series of conditions to be met so that the Moratalla dam project may be considered environmentally viable.
Intake tower (upstream from the dam) for replacement of irrigation easement and drainage chamber
Geology and seismology.
Geology
The Moratalla reservoir is located in the northeastern section of the Baetic System, which at the same time is the northwestern segment of the Peri-Mediterranean Alpine Orogen (aligned mountains with a runoff layers structure created during the Cretaceous and the Tertiary, centrifugally arranged in relation to the sea; Martín Algarra, 1987).
Within the Baetic System, the area under study is framed within the external area, just on the limit between the internal Pre-Baetic and the internal Sub-Baetic.
General geological map of the Baetic System
Within this area, the Moratalla river runs eastwards through marly materials, turning NE to avoid the calcareous outcrops of the Serrezuela de San Miguel, on whose eastern foothills rests the municipality Calasparra.
The basin is mainly shaped by waterproof Miocene marl, limestone and sand. The presence of limestone and marl from the Cenomanensis-Turonensis does not cause any waterproofing problems, given the predominance of marl and the impossibility of continuing towards the Argos river or downstream.
The basin is mostly made up of Tertiary materials based on limestone, marly limestone, calcareous marl and marl, with white and grayish-white coloring due to the continuous insets and lateral changes of facies.
Seismology
In November 1999, the proposal for classification of the Moratalla dam according to potential risk was submitted, and it received category A classification.
Pendulum
Plans
Plans
- Dam plant
(165 KB) - Longitudinal and transversal profiles of the dam. (105 KB)
- Transversal sections of the dam. (71 KB)
Ortophotos
Detail of the teeth on the wall at the entry of the spilling body
Situation
The reservoir associated with Moratalla´s dam and environment are inside the Cuenca of the Segura, in the Region of Murcia, to the N.O. of the Autonomous Community. Concretly there are located in the leaf 889, MORATALLA, from the IGN to scale 1: 50.000. The territory corresponds to the province of Murcia, Moratalla´s municipal area.
U.T.M. coordinates:
Reference system ETRS89. Time zone= 30
X=609307
Y=4.233.564
