Water supply to the Bavarian Forest
| Water supply to the Bavarian Forest
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| legal form | Zweckverband / corporation under public law |
| founding | November 28, 1963 |
| Seat | Deggendorf |
| management |
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| Number of employees | 65 |
| Branch | Water supply |
| Website | www.waldwasser.eu |
The water supply Bavarian Forest (WBW) is a special purpose association , based in Deggendorf , which on 28 November 1963 by seven counties ( Deggendorf , Passau , Freyung-Grafenau , Rain , Straubing-Bogen , Dingolfing-Landau and Cham ) and the town of Deggendorf to Covering the water needs of the communities in the Bavarian Forest was founded. Today the WBW supplies around 225,000 people in one hundred cities and communities with drinking water . The municipalities set up local networks and continue to supply the end users themselves. The non-profit association fulfills its task without the intention of making a profit.
history
In 1963 the special purpose association Fernwasserversorgung Bayerischer Wald was founded. Initially, the groundwater from the Moos well field (in the municipality of Moos near Plattling ) covered the needs of the long-distance water supply . This ensured the water supply in the Danube region as well as in the Bavarian Forest. The Free State of Bavaria later built the Frauenau drinking water reservoir between 1976 and 1983 . At the same time, the association built the Flanitz drinking water treatment plant at an altitude of 700 meters between Zwiesel and Frauenau. Since its commissioning, around 79 percent of the customers in the supply area have been supplied with water from the dam. For this reason, the name of the association was changed in 1986 to "Water Supply Bavarian Forest", or WBW for short.
Drinking water supply
Coverage area
The association area covers the area of seven districts with a total of around 8080 km². The supply area has a size of approximately 5500 km².
Drinking water production
The water supply of the Bavarian Forest is based on two extraction areas: the state drinking water reservoir Frauenau and the well field Moos.
The dam water is a typical soft surface water from the catchment area of the Hirschbach and the Kleiner Regens . Water flows into the dam from an almost exclusively forested drinking water protection area of around 30 km² . The area extends beyond the national borders to the Czech territory. The water is unpolluted by human influences and can therefore be released largely in its natural state. Due to the water level, the raw water from the drinking water reservoir reaches the Flanitz treatment plant near Frauenau.
Groundwater is pumped in the moss well field . Depending on the groundwater conditions, it is obtained through vertical gravel filler or horizontal filter wells of different depths . The modern vertical wells can even reach depths of several hundred meters. They consist of a vertical, perforated pipe with a gravel coating at groundwater level. A closed pipe guides the water upwards into the well head, which protects against contamination. In the horizontal filter wells that reach the shallower groundwater layers, a relatively wide closed shaft extends to the depth of the water. There are several star-shaped filter pipes laid horizontally on all sides, which enable a significantly higher delivery rate compared to vertical wells. In the Moos well field, one horizontal and one vertical well are currently operated.
Drinking water treatment
The drinking water treatment takes place in the drinking water treatment plant Flanitz (TWA Flanitz) as well as in the groundwater pumping station Moos (GPW Moos).
TWA Flanitz
In the TWA Flanitz, the surface water from the Frauenau drinking water reservoir essentially undergoes two treatment processes before it is supplied as drinking water and meets the strict legal requirements of the drinking water ordinance in terms of chemical and corrosion technology. Two filter stages are used in the TWA Flanitz . After the formation of flakes , organic pollution as well as iron and manganese are eliminated in the first filter stage via open multilayer filters. In the second filter stage, the soft and therefore pipe-damaging surface water is hardened by Jura limestone after being enriched with carbon dioxide . The equilibrium pH value is set at the end of the treatment process with lime water. The first expansion stage of the processing plant was designed for a capacity of around 1,800 m 3 / h, which corresponds to around 36,000 m 3 per day. However, the demand for water increased in the early 1990s. For this reason, the implementation of the second expansion stage and thus the doubling of the system output was decided and implemented in 1999. A container volume of around 6,000 m 3 was also created for the intermediate storage of drinking water .
GPW moss
The groundwater is also treated in the Moos groundwater pumping station. The groundwater is already largely purified naturally by passing through the soil layers. In the GPW Moos only a few steps are required for the treatment until it meets the requirements for drinking water. The water is first enriched with oxygen in an open cascade aeration. The iron and manganese oxides that form are retained in the downstream open quartz gravel filters. Even without the addition of chlorine , the drinking water complies with the strict requirements of the Drinking Water Ordinance. With the hardness range "hard", it is classified as naturally hard water, as can be found everywhere between the Alps and the Danube.
Drinking water distribution
The drinking water is distributed with the help of a more than 850 km long pipeline network, starting from the two extraction and treatment locations to the individual customers in the supply area. Almost 50 elevated tanks with a total storage volume of more than 85,000 m 3 and more than 40 pumping stations ensure security of supply in the supply area. In this way, the peak demand can be met and the drinking water can be supplied with the necessary pressure.
Security of supply
Both the Frauenau dam and the systems for extracting groundwater in the Moos fountain field ensure that customers receive a sufficient amount of top quality drinking water at all times. According to the water supply contract , the WBW can take up to 15 million m 3 of water annually from the dam. It serves the customers of the WBW as a large and reliable reservoir for drinking water. A water quality laboratory, which is already integrated in the operating building of the dam, is used for constant biological-chemical monitoring of the water from the dam. Numerous measuring devices are used to continuously record all data that are important for operation and safety. In the Moos well field, in addition to a horizontal and vertical well, another horizontal well is kept ready for emergencies. The maximum groundwater withdrawal as quaternary water is 310 l / s.