Los Charcos Reservoir
Background
Overview:
Damages caused by torrential rains, historically occurring on the left margin of the Mundo river in urban and agricultural areas, have been considered catastrophic in many occasions, so it became necessary to urgently establish a defense and canalization plan to be implemented in the area subject to study.
To that effect, the General Directorate of Hydraulic Works approved the public information file of the Segura Basin General Flood Defense Plan on November 12, 1986, within the Public Investment Program framework.
The anticipated actions of the General Flood Defense Plan included, in particular, the Defense and canalization of the main affluents on the left margin of the Mundo river.
After the catastrophic damages caused by the flash floods of July and October 1986, the Official State Gazette published Royal Decree 4/1987 dated November 13, whose annex nº 2 literally quotes the investment required for the execution of the necessary works on the left margin of the Mundo river in Albacete included in the Defense Program.
In May 1987, after the districts affected by the floods held meetings with national, Autonomous Community of Castilla-La Mancha and Segura Hydrographic Confederation authorities, asking for a defense plan for the basin of the Mundo river; road engineer Andrés Martínez Muñoz drafted the Mundo river left margin flood study, describing the serious floods periodically occurring in the plains of the Mundo river and its affluents.
View of the parameter upstream from the waterway.
Likewise, during the drafting of this study, a meeting was held at the request of the Directors of Planning and Agricultural Policy of the Autonomous Community of Castilla-La Mancha with RENFE and experts working for the Segura Hydrographic Confederation, where they pointed out possible actions to undertake by the different coordinated agencies.
In January 1991, drafting of the Los Charcos Dam Construction Project (Tobarra-Albacete) was completed. Said project was approved on April 30, 1993.
Pursuant to the resolution issued by the General Directorate of Hydraulic Works and its notice published on Official State Gazetteº 265 of November 5, 1993, the public tender for the construction of the Los Charcos dam was issued, with a deadlines for proposals established on December 9, 1993.
On August 8, 1994, the General Directorate of Hydraulic Works decided to select Variant 11.3 solution from those presented by the temporary joint venture (UTE in Spanish) of Ferrovial SA and Obras Hidráulicas y Viarias SA with a net estimate of 419,636,000 pesetas and a deadline for completing the works of twelve months. The construction project was drafted in September 1994.
In February 1995, the Technology and Structural Control Area issued a favorable report, including some recommendations about location and type of dam.
Subsequently, on September 18, 1995, the works were awarded to the aforementioned UTE.
The document verifying readiness for construction was subscribed on December 1, 1995.
Crest, general view from the left abutment
Modified projects:
On July 18, 1996, the General Directorate of Hydraulic Works authorized the drafting of Modified Project Nº 1, issuing the pertinent Partial Temporary Suspension Act. The project, which included recommendations issued by the Technology and Structural Monitoring Area on the benefits of building an arch-gravity dam, slightly modifying its location downstream and moving it away from the existing fault on the right abutment, was finally approved on December 12, 1997, with an Additional Net Budget of 41,488,311 pesetas.
On May 27, 1997, the General Directorate of the Hydraulic Works authorized the assignment of the works to the UTE of Ferrovial SA and Compañía de Obras Castillejos SA; and the pertinent assign agreement was subscribed by means of public deed on July 14, 1997.
During the execution of the works, and according to the scale model test carried out by the CEDEX in order to study the suitability of the sluice and the return of the water to the watercourse, authorization was requested by means of a report dated December 1, 1997, which included the necessary modifications to the spilling basin to adapt it to the test, to draft Modified Project Nº. On May 21, 1998, the General Directorate of Hydraulic Works authorized the drafting of such project, submitted in June 1998, and receiving final technical approval on January 18, 1999.
Supplementary project:
Likewise, during the development of the works, other needs were perceived, which prompted the request for authorization to draft Supplementary Project Nº1 from the General Directorate of Hydraulic Works on December 1, 1997, which included urbanization works of the exploitation buildings, the delimitation of the basin´s flood area and the expropriated strip of access road, as well as the temporary closing of one of the drains and installation of a regulating valve on the other. On June 1, 1998, the General Directorate of Hydraulic Works authorized the drafting of the aforementioned Supplementary Works Project, submitted in June 1998.
Works were completed by May 30, 2000 with a total budget of 585,000,369 pesetas (3,518,037 euros).
Access
The access to the dam of the Charcos from Albacete is realized following the described itinerary later: exit from Albacete in direction Murcia for the highway A-30, I turn 290 aside in the exit to join to the road N-301, continuing for the same one in direction Murcia (in parallel to the highway) up to the P.K. 292,5, where the approach road takes to the right to the toma, which places to 4 km from this point. The total length of the tour from Albacete is of approximately 45 km.
The road of access to the dam also can think from Tobarra´s locality, being this one the most short way if one accedes from Murcia. In this case, it will leave of Tobarra for the road N-301 towards Albacete and will be still the same up to coming to the P.K. 292,5 in the one that is the detour towards the dam.
The location of the reservoir can be seen in the following map:
Characteristics
| DAM SITUATION | |
|---|---|
|
Province
|
Albacete |
|
Municipal Territory
|
Tobarra |
|
Watercourse
|
Los Charcos |
|
Hydrographic basin
|
Segura |
|
BASIN DATA
|
|
|
Surface of the hydrographic basin
|
28.00 km² |
|
Maximum height of the basin
|
1,035.00 m |
|
RESERVOIR DATA
|
|
|
Surface of the reservoir at the Maximum Normal Level(MNL)
|
7.45 ha |
|
Capacity at MNL
|
0.35 hm³ |
|
Height of the MNL
|
738.00 m |
|
DAM BODY
|
||
|---|---|---|
|
Type
|
Arch-gravity | |
|
Top spot height
|
746.20 m | |
|
Maximum height from fundaments
|
30.70 m | |
|
Top length
|
198.00 m | |
|
Top width
|
3.00 m | |
|
Bed height in the dam
|
724.00 m | |
|
CHUTE
|
||
|
Total number of chutes
|
1 | |
|
Draining flow at Project Flood Level (NAP)
|
9,57 m³/s | |
|
Type
|
Front with spillway with fixed lips | |
Installations. Detail of the monitoring box located on the top.
Purpose
The purpose of the dam is the control of floods occurring in the Los Charcos watercourse, trying to reduce the effects of floods, historically occurred in the city of Tobarra.
As a consequence of the lamination of floods produced by the dam, it is reduced the peak of the hydrograms entering through the Mundo river into the Camarillas reservoir; this allows such a river to transfer its floods with a reduced flow to the Segura river, which is the main purpose of the General Flood Defence Plan in the Segura basin.
Chute seen by underwater
>
Territorial and Administrative Context
Physical features of the basin.
The catchment basin draining into the Los Charcos dam has a surface area of 28 km2, limited to the north and the east by the Cañada, Balsaín and Ballesteros mountains, to the west by Los Pachecos and to the south by the Navajuelos range.
The basin has a mountain morphology, where the highest elevations are about 1,000 m (the Berrueco peak is 1,035 m). The location of the dam benefits from the narrowing between the two mountains of Navajuelos, closing the basin at 724 m, when the riverbed goes into a sharper relief.
The longest riverbed is 9.8 km, beginning at a height of 934 m and ending at 724 m in the dam enclosure. Therefore, the average slope is 2.1%.L
Perspective of the reservoir basin, view from the dam crest
Environmental information.
The surroundings of the reservoir of Los Charcos watercourse is characterized by a tempered Mediterranean climate.
Refilling of the carbonated aquifers happens by means of direct rainwater infiltration, while in the detritic it is also by direct connection with the watercourse (in the rainy season) as well as by irrigation which produces significant refilling. Discharge happens essentially through springs and by extracting water from wells and pumping.
As previously indicated, the waterproof enclosure and Charcos reservoir will help refilling the aquifer, which is not a problem because it is a flood laminating dam.
Geology and seismology.
Geology
In this paragraph, we briefly describe the geological-geotechnical features of the area of influence of the reservoir and the foundations of the Los Charcos dam, as well as the seismic features of the area.
From a geological point of view, it is a transition area between the two most important structural units in the Iberian Peninsula: the Iberian System (in the north) and the Pre-Baetic Zone of the Baetic System (in the south).
The tectonics of the area is complex due to the transitional character that defines it, and it is characterized by sharp changes of direction among the different formations. In the surroundings of the basin, there are NE_NW structures, such as Los Búhos and the Navajuelos mountains.
The materials present belong to different eras, from the Mesozoic to the Quaternary. Most of them are calcareous Jurassic which make up almost all the ranges in the area; Cretaceous and Tertiary (represented by Miocene materials) are scarcely represented and emerge in the areas with a softer relief; finally, the Quaternary appears above the previous series as encrusted deposits, runoff layers and alluvial fans.
Downstream view of the watercourse from the dam crest
Seismology
The Los Charcos dam is located, according to the Seismic Resistance Regulation (NCSE-02), within an area of basic seismic acceleration of 0.07g in the municipality of Tobarra, which is the nearest town to the dam.
Among the devices installed in the dam, there is a seismograph to detect any seismic movements which could occur in the area. Since its installation until this document was drafted, no significant event has been recorded.
Based on the possible risk of breakage, the Los Charcos dam is classified as category A.
Planos
Plans
(298 KB)Ortophotos
Monitoring. Precipitation gauge of the weather station located above a masonry column in the forecourt of the administration house
Situation
As it has been exhibited previously, the dam of the ravine of the Puddles places in the actions of defense of the left margen of the river Mundo, inside the General Plan of Defense against Avenues of the Cuenca of the Segura.
The ravine of the Puddles places in the zone Suroriental of the province of Albacete. It is a short riverbed, of less than 10 km, which joins to the ravine of the Entresierras and comes up to the population of Tobarra, spilling to the ravine, once overcome this locality. The latter riverbed is a tributary of Tobarra´s creek, which course of water comes together in turn with the river Mundo for his margin left side, at a height of the tail of the reservoir of Camarillas.
The dam is to the north of Tobarra´s locality, to approximately 6 km from distance. The areas occupied by the glass belong to Tobarra´s municipal area.
Depending on the potential risk of break, the dam of the Charcos qualifies inside the category To.
U.T.M. coordinates:
Reference system ETRS89. Time zone= 30
X=613.179
Y=4.278.620
