At the Dörnthaler pond built in the years 1842-1844, the operating facilities (basic and operating outlet), which are still in their original state, no longer correspond to the state of the art and must be renewed.
The Dörnthaler pond is after SächsWG part of the water body I. order Revierwasserlaufanstalt Freiberg and is operationally the Oberer Revierwasserlaufanstalt Freiberg (RWA), which serves mainly the drinking water supply. The stored in the dam Rauschenbach water flows through associated trenches and florets of the Revierwasserlaufanstalt Freiberg the Dörnthaler pond. Here, the intermediate storage and the demand-based delivery in the artificial moat in the direction of Großhartmannsdorf or via the Haselbach to the dam Saidenbach.
The Dörnthaler pond is assigned to the dam class 1 according to DIN 19700 part 11.
The dam is also used for flood protection.
The following scope of services must be provided:
- Leistungsbild Ingenieurbauwerke, Part 3, Section 3 HOAI 2013, work phases 1 to 9,
- Scope of Structural Design, Part 4, Section 1 HOAI 2013, work phases 1 to 6,
- Leistungsbild Technical Equipment, Part 4, Section 2 HOAI 2013, work phases 1 to 9,
- Consultancy Environmental Impact Study according to Annex 1, No. 1.1 HOAI 2013, work phases 1 to 4,
- Consultancy Geotechnics according to Annex 1, No. 1.3 HOAI 2013, basic services a to c.
A new bottom outlet system with an internal diameter of at least 600 mm has to be planned. A slide chamber on the air side of the dam construction is considered by the AG as operationally necessary.
The following functions for the bottom outlet ("deep harrow") are to be provided in the required slide chamber on the air side:
- Control of charges between 0 - 2,0 m
- Ecological minimum water fee 0,005 m
- Abfischung / emptying, ensuring the continuity for fish and for coarse material.
The necessary structures on the air side of the dam must be planned in such a way that no structural parts project beyond the existing terrain level.
It is the renovation of the operating outlet for the Dörnthaler pond to plan. The planning includes the construction of a new valve chamber / distributor building (hereinafter referred to as distributor building). In the context of the variant investigation, the arrangement of a hydropower plant for grid feed-in and self-supply of the location of the LTV in Dörnthal to investigate. For the existing operating outlet DN 700 is currently no camera precaution before, there is a attitude report from 30/10/2013 [11] available. It is intended to remediate this with a statically effective inliner. As a water-side closure a harrow (slide, contactor), which is operated via a linkage, provide. For the existing Striegelhaus a replacement building is to be planned. This requires coordination with the conservation authorities.
There is a new Striegelhaus with harrow to plan.
As a water-side closure for the mill line a harrow (slide, contactor), which is operated via a linkage to plan. For the existing Striegelhaus a replacement building is to be planned. This requires coordination with the conservation authorities.
environmental Impact study
Documents for the official determination of the EIA obligation in accordance with § 5 UVPG (general preliminary examination of the individual case according to Annex 1 UVPG) taking into account the information and test criteria according to Annexes 2 and 3 UVPG
FFH preliminary examination regarding the impact of the Natura 2000 area "Freiberg mine ponds"
The documents to be prepared must describe both the project itself as well as its location, impact factors and effective area, with a detailed description of the protected area and species protection situation.
Geotechnics / subsoil assessment and foundation consulting
Execution of a subsoil assessment and start-up consultation with research and inclusion of the results of already conducted subsoil investigations. Integration of the obtained data in the variant investigation.
For the exploration work according to VOB (field work) and laboratory work according to VOL, a task and performance description has to be worked out. In addition, the contract documents must be put together for a public invitation to tender. When soliciting offers, their evaluation, examination and negotiation with bidders is to participate.
The services for exploration and laboratory work must be coordinated and monitored.
For the water management facilities of the new basic discharge / service outlet and the building equipment, the EMSR technology, lightning protection equipment and, if applicable, the technical equipment for a turbine in the service outlet are to be planned.