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110-750: The Breitentalskopf is a hill in the Harz Mountains of central Germany , that rises southeast of Sieber in the district of Göttingen in Lower Saxony . It is 579.1 m high and separates the River Sieber from the Breitental valley (with its stream, the Tiefenbeek ), that gave the hill its name. Towards the southeast is the ridge of the Aschentalshalbe . This Göttingen district location article

220-446: A canal's full capacity may cause flooding to spread to other waterways and areas of the community, which causes damage. Defenses (both long-term and short-term) can be constructed to minimize damage, which involves raising the edge of the water with levees , embankments or walls. The high population and value of infrastructure at risk often justifies the high cost of mitigation in larger urban areas. The most effective way of reducing

330-637: A 1 in 1000 year flood (light blue) and low-lying areas in need of flood defence (purple). The most sustainable way of reducing risk is to prevent further development in flood-prone areas and old waterways. It is important for at-risk communities to develop a comprehensive Floodplain Management plan. In the US, communities that participate in the National Flood Insurance Program must agree to regulate development in flood-prone areas. One way of reducing

440-422: A breeding pair has settled in the eastern Harz as the result of a wildlife reintroduction project. The ring ouzel prefers semi-open stone runs and lightly wooded transition zones between treeless raised bogs and forests . The Harz is home to one of its few, isolated breeding areas in central Europe. Its main distribution area extends across northwest Europe, including large parts of England and Scotland, as well as

550-511: A certain amount of space in which floodwaters can fill. Other beneficial uses of dam created reservoirs include hydroelectric power generation, water conservation , and recreation. Reservoir and dam construction and design is based upon standards, typically set out by the government. In the United States, dam and reservoir design is regulated by the US Army Corps of Engineers (USACE). Design of

660-556: A coast). The spawning grounds for fish and other wildlife habitats can become polluted or completely destroyed. Some prolonged high floods can delay traffic in areas which lack elevated roadways. Floods can interfere with drainage and economical use of lands, such as interfering with farming. Structural damage can occur in bridge abutments , bank lines, sewer lines, and other structures within floodways. Waterway navigation and hydroelectric power are often impaired. Financial losses due to floods are typically millions of dollars each year, with

770-664: A consequence of the mining industry in the Upper Harz, was largely destroyed by a bark beetle outbreak and a storm of hurricane proportions in November 1800. This largest known bark beetle infestation in the Harz was known as the Große Wurmtrocknis , and destroyed about 30,000 hectares (74,000 acres) of spruce forest and lasted about for 20 years. The woods were largely reforested with spruce. Continuous problems with bark beetle and storms were

880-553: A consequence of this it is also referred to as the "Classic Geological Square Mile" ( Klassischen Quadratmeile der Geologie ). There is a room devoted to geology in the Harz Museum in Wernigerode. The vegetation of the Harz mountains is divided into six altitudinal zones : From the edge of the Harz to 700 m above sea level beech woods dominate, especially the wood-rush beech woods on locations poorly supplied with nutrients where

990-513: A dam and reservoir follows guidelines set by the USACE and covers topics such as design flow rates in consideration to meteorological, topographic, streamflow, and soil data for the watershed above the structure. The term dry dam refers to a dam that serves purely for flood control without any conservation storage (e.g. Mount Morris Dam , Seven Oaks Dam ). Flood control channels are large and empty basins where surface water can flow through but

1100-417: A flood does happen, the city can recover quickly and costs are minimized. For example, homes can be put on stilts, electrical and HVAC equipment can be put on the roof instead of in the basement, and subway entrances and tunnels can have built-in movable water barriers. New York City began a substantial effort to plan and build for flood resilience after Hurricane Sandy . Flood resilience technologies support

1210-477: A keen interest in science (see Goethes: Wahrheit und Dichtung ). In 1777, Goethe climbed the Brocken, departing from Torfhaus. At that time, there was still no mass tourism on the Brocken; in the year 1779 only 421 walkers were recorded. Goethe described his feelings on the summit later, as follows: So lonely, I say to myself, while looking down at this peak, will it feel to the person, who only wants to open his soul to

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1320-468: A lack of old trees and natural brooks). Through improvements to its habitat, including the renaturalisation of waterways and the creation of relatively undisturbed peaceful areas, the black stork population has now recovered. A typical mammal of such deciduous woods is the European wildcat ( Felis silvestris ), that has established a stable population in the Harz. It prefers the diverse wooded areas, which offer

1430-545: A line from Ilsenburg to Bad Lauterberg , which roughly separates the catchment areas for the Weser (Upper Harz) and Elbe (Lower Harz). Only on the southeastern perimeter of the Upper Harz, which is also called the High Harz ( Hochharz ) (Goslar, Göttingen and Harz districts), does the mountain range exceed 1,000 m above NN on the Brocken massif. Its highest peak is the Brocken (1,141 m), its subsidiary peaks are

1540-622: A lowhead dam, is most often used to create millponds , but on the Humber River in Toronto, a weir was built near Raymore Drive to prevent a recurrence of the flood damage caused by Hurricane Hazel in October 1954. The Leeds flood alleviation scheme uses movable weirs which are lowered during periods of high water to reduce the chances of flooding upstream. Two such weirs, the first in the UK, were installed on

1650-405: A method of using water to control flooding was discovered. This was accomplished by containing 2 parallel tubes within a third outer tube. When filled, this structure formed a non-rolling wall of water that can control 80 percent of its height in external water depth, with dry ground behind it. Eight foot tall water filled barriers were used to surround Fort Calhoun Nuclear Generating Station during

1760-469: A portion of the facility. AquaFence consists of interlocking panels which are waterproof and puncture-resistant, can be bolted down to resist winds, and use the weight of floodwater to hold them in place. Materials include marine-grade batlic laminate, stainless steel, aluminum and reinforced PVC canvas. The panels are reusable and can be stored flat between uses. The technology was designed as an alternative to building seawalls or placing sandbags in

1870-466: A result of deliberate forest management . Sycamore trees are also found in these woods. Spruce woods thrive in the highest locations from about 800 m to the tree line at around 1,000 m above sea level. These woods are also home to some deciduous trees such as rowan, silver and downy birches ( Betula pendula and Betula pubescens ) and willows ( Salix spec. ). Conditions of high humidity foster an environment rich in mosses and lichens . In spite of

1980-416: A result of the increasingly continental climate on the eastern edge of the Harz, the common beech gives way to mixed forests of sessile oak. At intermediate heights of between 700 and 800 m above sea level, mixed woods of spruce ( Picea abies ) and common beech would predominantly be found under natural conditions. However, apart from a few remnants, these were supplanted a long time ago by spruce stands as

2090-419: A rich variety of food. The animal kingdom of the mixed beech and spruce woods is also diverse. Species that thrive in mixed forest are especially at home. For example, the mixed mountain forest is the natural habitat of the capercaillie ( Tetrao urogallus ). The Tengmalm's owl ( Aegolius funereus ) may also be found here. It breeds almost exclusively in black woodpecker holes in old beeches, and needs, unlike

2200-406: A role. Melic grass beech woods are found in the few places where there is an abundance of nutrients and bases , e. g. over dolerite and gneiss formations, and they have a vegetation layer rich in variety and luxuriant growth. Here, too, the common beech dominates, mixed, for example, with sycamore, ash ( Fraxinus excelsior ), hornbeam ( Carpinus betulus ) and Scots elm ( Ulmus glabra ). As

2310-407: A type of damselfly , can be seen by streams in the Harz. The dipper ( Cinclus cinclus ), which is found everywhere on Harz streams, occurs almost exclusively in the highlands. Its habitat is very fast-flowing, clear mountain streams with wooded banks. It can dive and run under water along the stream bed. It turns stones over in its search for food. The grey wagtail ( Motacilla cinerea ) also uses

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2420-629: A wide range of flood management methods including but are not limited to flood mapping and physical implication measures. Flood risk management looks at how to reduce flood risk and how to appropriately manage risks that are associated with flooding. Flood risk management includes mitigating and preparing for flooding disasters, analyzing risk, and providing a risk analysis system to mitigate the negative impacts caused by flooding. Flooding and flood risk are especially important with more extreme weather and sea level rise caused by climate change as more areas will be effected by flood risk. Flood mapping

2530-455: Is a stub . You can help Misplaced Pages by expanding it . Harz Mountains The Harz has a length of 110 kilometres (68 mi), stretching from the town of Seesen in the northwest to Eisleben in the east, and a width of 35 kilometres (22 mi). It occupies an area of 2,226 square kilometres (859 sq mi), and is divided into the Upper Harz ( Oberharz ) in the northwest, which

2640-559: Is a broad term that includes measures to control or mitigate flood waters, such as actions to prevent floods from occurring or to minimize their impacts when they do occur. Flood management methods can be structural or non-structural: There are several related terms that are closely connected or encompassed by flood management. Flood management can include flood risk management, which focuses on measures to reduce risk, vulnerability and exposure to flood disasters and providing risk analysis through, for example, flood risk assessment . In

2750-575: Is a flood defense system designed to protect people and property from inland waterway floods caused by heavy rainfall, gales, or rapid melting snow. The SCFB can be built to protect residential properties and whole communities, as well as industrial or other strategic areas. The barrier system is constantly ready to deploy in a flood situation, it can be installed in any length and uses the rising flood water to deploy. When permanent defenses fail, emergency measures such as sandbags , inflatable impermeable sacks, or other temporary barriers are used. In 1988,

2860-661: Is a native of the bilberry-rich bog spruce woods. Only a few animals are able to survive the extreme conditions of the raised bogs . Examples of these are the Alpine emerald dragonfly ( Somatochlora alpestris ), which only occurs in Lower Saxony in the Harz, and is endangered in Germany, and the Subarctic darner ( Aeshna subarctica ), a damselfly which is threatened with extinction. Rocks and stone runs are important habitat components for

2970-681: Is a related but separate concept describing a broader set of strategies taken to reduce flood risk and potential impact while improving resilience against flood events. As climate change has led to increased flood risk an intensity, flood management is an important part of climate change adaptation and climate resilience . For example, to prevent or manage coastal flooding , coastal management practices have to handle natural processes like tides but also sea level rise due to climate change. The prevention and mitigation of flooding can be studied on three levels: on individual properties, small communities, and whole towns or cities. Flood management

3080-472: Is a tool used by governments and policy makers to delineate the borders of potential flooding events, allowing educated decisions to prevent extreme flooding events. Flood maps are useful to create documentation that allows policy makers to make informed decisions about flood hazards. Flood mapping also provides conceptual models to both the public and private sectors with information about flooding hazards. Flood mapping has been criticized in many areas around

3190-482: Is characterised by regular precipitation throughout the year. Exposed to westerly winds from the Atlantic, heavy with rain, the windward side of the mountains has up to 1,600 mm of rain annually (West Harz, Upper Harz, High Harz); in contrast, the leeward side only receives an average of 600 mm of precipitation per annum (East Harz, Lower Harz, Eastern Harz foothills). The Harz is the most geologically diverse of

3300-467: Is effective at managing flooding. However, it is best practice within landscape engineering to rely more on soft infrastructure and natural systems , such as marshes and flood plains , for handling the increase in water. Flood management can include flood risk management, which focuses on measures to reduce risk, vulnerability and exposure to flood disasters and providing risk analysis through, for example, flood risk assessment . Flood mitigation

3410-520: Is indicated and in such cases environmentally helpful solutions may provide solutions. Natural flooding has many beneficial environmental effects. This kind of flooding is usually a seasonal occurrence where floods help replenish soil fertility, restore wetlands and promote biodiversity . Flooding has many impacts. It damages property and endangers the lives of humans and other species. Rapid water runoff causes soil erosion and concomitant sediment deposition elsewhere (such as further downstream or down

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3520-404: Is not retained (except during flooding ), or dry channels that run below the street levels of some larger cities , so that if a flash flood occurs the excess water can drain out along these channels into a river or other bodies of water . Flood channels are sometimes built on the former courses of natural waterways as a way to reduce flooding. Channelization of this sort was commonly done in

3630-735: Is part of environmental engineering . It involves the management of water movement, such as redirecting flood run-off through the use of floodwalls and flood gates to prevent floodwaters from reaching a particular area. Flood mitigation is a related but separate concept describing a broader set of strategies taken to reduce flood risk and potential impact while improving resilience against flood events. These methods include prevention, prediction (which enables flood warnings and evacuation), proofing (e.g.: zoning regulations), physical control ( nature-based solutions and physical structures like dams and flood walls ) and insurance (e.g.: flood insurance policies). Flood relief methods are used to reduce

3740-527: Is up to 800 m high, apart from the 1,100 m high Brocken massif, and the Lower Harz ( Unterharz ) in the east which is up to around 400 m high and whose plateaus are capable of supporting arable farming. The following districts ( Kreise ) fall wholly or partly within the Harz: Goslar and Göttingen in the west, Harz and Mansfeld-Südharz in the north and east, and Nordhausen in the south. The districts of

3850-842: The Roßtrappe , could indicate an earlier Celtic occupation of the Harz. The Harzgau itself was first mentioned in a deed by the Emperor, Louis the Pious , from the year 814, in which it was referred to by its High German form, Hartingowe . According to the Fulda annals of 852, the Harzgau was occupied by the Harudes and after whom the Harudengau ( Harudorum pagus ) was named. Harud , from which Hard , Hart and Harz are derived, means forest or forested mountains, and

3960-436: The 2011 Missouri River Flooding . Instead of trucking in sandbag material for a flood, stacking it, then trucking it out to a hazmat disposal site, flood control can be accomplished by using the on site water. However, these are not fool proof. A 8 feet (2.4 m) high 2,000 feet (610 m) long water filled rubber flood berm that surrounded portions of the plant was punctured by a skid-steer loader and it collapsed flooding

4070-657: The Fichtel Mountains and Rhenish Massif . They were, however, heavily eroded due to their height (up to 4 km) and were later covered over by Mesozoic rocks. From the Early Cretaceous and into Late Cretaceous times the Harz was uplifted in a single block by tectonic movements and, particularly during the Tertiary period, the younger overlying strata were eroded and the underlying base rock left standing as low mountains. The most important uplift movements were during

4180-797: The Heinrichshöhe (1,044 m) to the southeast and the Königsberg (1,023 m) to the southwest. Other prominent hills in the Harz are the Acker- Bruchberg ridge (927 m), the Achtermannshöhe (925 m) and the Wurmberg (971 m) near Braunlage . In the far east, the mountains merge into the East Harz foothills (Harz district, Saxony-Anhalt), which are dominated by the Selke Valley. Part of

4290-649: The Inner German border ran through the Harz, the west belonging to the Federal Republic of Germany (West Germany) and the east to the German Democratic Republic (East Germany). Today the Harz forms a popular tourist destination for summer hiking as well as winter sports. About 700,000 to 350,000 years ago Homo erectus hunted in and around the Harz near Bilzingsleben (Thuringia), Hildesheim and Schöningen (Lower Saxony). The Neanderthals entered

4400-479: The River Aire in October 2017 at Crown Point, Leeds city centre and Knostrop . The Knostrop weir was operated during the 2019 England floods . They are designed to reduce potential flood levels by up to one metre. Coastal flooding is addressed with coastal defenses, such as sea walls , beach nourishment , and barrier islands . Tide gates are used in conjunction with dykes and culverts. They can be placed at

4510-571: The Wolkenhäuschen ("Little House in the Clouds") on the Brocken. As a young man, the famous German poet, Goethe visited the Harz several times and had a number of important lifetime experiences. These included his walks on the Brocken and his visit to the mines in Rammelsberg. Later, his observations of the rocks on the Brocken led to his geological research. His first visit to the Harz awakened in him

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4620-523: The common beech ( Fagus sylvatica ) is often the only tree species. In lower, drier locations the English oak ( Quercus robur ) and sessile oak ( Quercus petraea ) occur as well. Sycamore trees ( Acer pseudoplatanus ) may be found growing in wetter places. During times of decay and rejuvenation when there is plenty of light, light-dependent pioneers such as rowan ( Sorbus aucuparia ), silver birch ( Betula pendula ) and pussy willow ( Salix caprea ) play

4730-545: The limestone deposits around Elbingerode and the Gabbro of Bad Harzburg . The landscapes of the Harz are characterised by steep mountain ridges, stone runs , relatively flat plateaus with many raised bogs and long, narrow V-shaped valleys , of which the Bode Gorge , the Oker and Selke valleys are the best known. A representative cross-section of all the Harz rocks is displayed on

4840-434: The peregrine falcon ( Falco peregrinus ) and ring ouzel ( Turdus torquatus ). The peregrine, which is threatened with extinction here, needs steep rock outcrops with little vegetation. After its population had died out in the Harz, a breeding pair was re-established in the region. A crucial contribution has been made by extensive efforts to promote quiet areas in the ancestral breeding grounds of this shy species. Since 1980,

4950-487: The pygmy owl ( Glaucidium passerinum ) which is threatened with extinction and which lives in the submontane to subalpine zones within mixed and pine forests interspersed with open areas. They prefer spruce woods for breeding, but feed in more open stands of trees or on open moorland. Like the black stork , the pygmy owl had long since disappeared from the Harz, but returned in the 1980s of its own volition, as its ancestral homeland once again became more natural, so that there

5060-458: The 1960s, but is now often being undone, with "rechannelization" through meandering, vegetated, porous paths. This is because channellizing the flow in a concrete chute often made flooding worse. Water levels during a flood tend to rise, then fall, exponentially. The peak flood level occurs as a very steep, short spike; a quick spurt of water. Anything that slows the surface runoff (marshes, meanders, vegetation, porous materials, turbulent flow,

5170-854: The Bode. The Wipper is fed by the Eine . The Rhume is joined by the Söse and the Oder; the latter being fed by the Sieber . The Zorge , the Wieda and the Uffe all flow into the Helme. → See List of hills in the Harz → See List of rock formations (crags, tors, etc.) in the Harz Climatically a hill range has lower temperatures and higher levels of precipitation than the surrounding land. The Harz

5280-487: The Brocken without special permission, and the lighting of fires was forbidden. The first attempts at forest conservation in the Harz were centred on the Brocken, and began with a far-sighted nature conservation act over 275 years ago. In 1718, Count Christian Ernest of the House of Stolberg issued an ordinance in which destruction or damage to the forest on the Brocken would be severely punished. In 1736, Christian Ernest also built

5390-565: The German Mittelgebirge , although it is overwhelmingly dominated by base-poor rocks. The most common rocks lying on the surface are argillaceous shales , slaty ( geschieferte ) greywackes and granite intrusions in the shape of two large igneous rock masses or plutons . The Gießen-Harz surface layer of the Rhenohercynian zone , which is widespread in the Harz, consists mainly of flysch . Well-known and economically important are

5500-635: The Harudes were the residents or dwellers in the Harud. Of more recent origin are settlements whose names end in –rode , a suffix that is first discernable in the Harzgau from the mid-9th century. Where the founders of these villages came from is unknown. Charlemagne declared the Harz a restricted imperial forest or Reichsbannwald . The Saxon Mirror ( Sachsenspiegel ), the oldest German law book ( Rechtsbuch ), probably published around 1220/30 at Falkenstein Castle in

5610-994: The Harz The largest rivers in the Harz are the Innerste , the Oker and the Bode in the north; the Wipper in the east; and the Oder in the south. The Innerste merges into the Leine and its tributaries are the Nette and the Grane . The rivers Radau , Ecker and Ilse all discharge into the Oker. The Hassel , the Selke and the Holtemme (whose main tributary is the Zillierbach ) flow into

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5720-409: The Harz are some of the best preserved in central Europe. They were formed at the end of the last ice age about 10,000 years ago. A significant proportion of the vegetation on these raised bogs is made up of peat mosses ( Sphagnum spec. ). The flarks ( Schlenken ) and the hummocks ( Bulten ) are home to different species of flora. In the flarks, for example, Sphagnum cuspidatum is found, whereas

5830-457: The Harz point to the use of this prehistoric adhesive by Neanderthals about 50,000 years ago. The Upper Palaeolithic Revolution , about 40,000 years ago, saw Homo sapiens move from Africa into Europe, including to the Harz region, where they appear to have ousted the Neanderthals and subsequently settled here. Many discoveries in the Harz, such as the bronze club of Thale, which was found by

5940-727: The Jordanshöhe near Sankt Andreasberg near the car park (see photo). The formation and geological folding of the Harz hills began during a prominent phase of the Palaeozoic era, in the course of the Hercynian mountain building of the Carboniferous period , about 350 to 250 million years ago. At that time in the history of the Earth , numerous high mountains appeared in Western Europe, including

6050-523: The Selke valley, later made the imperial restriction clear: "Whoever rides through the Harz Forest, must unstring his bow and crossbow and keep dogs on a line – only crowned royalty ( gekrönte Häupter ) are allowed to hunt here". Eike von Repkow's Sachsenspiegel which, for centuries, formed the basis on which German law was administered, described the Harz as a place where wild animals are guaranteed protection in

6160-588: The Upper Harz are Goslar and Göttingen (both in Lower Saxony), whilst the Lower Harz is on the territory of Harz and Mansfeld-Südharz districts (both in Saxony-Anhalt). The Upper Harz is generally higher and features fir forests, whilst the Lower Harz gradually descends into the surrounding area and has deciduous forests interspersed with meadows. The dividing line between Upper and Lower Harz follows approximately

6270-504: The amount of mitigation needed to protect humans and buildings from flooding events. Similarly, flood warning systems are important for reducing risks. Following the occurrence of flooding events, other measures such as rebuilding plans and insurance can be integrated into flood risk management plans. Flood risk management strategy diversification is needed to ensure that management strategies cover several different scenarios and ensure best practices. Flood risk management aims to reduce

6380-546: The animals in these streams need to be well suited to high velocities. Only a few species, such as fish, swim actively against the stream. The most common species are brown trout ( Salmon trutta forma fario ) and bullhead ( Cottus gobio ). Much richer in variety, by contrast, is the range of species in the system of crevices under the streambed. In addition to the insects and fish hatchlings that thrive here, may be found protozoons , flatworms ( Turbellaria ) and water mites ( Hygrobatoidea ). Other species of animals cling fast to

6490-430: The beech woods, with their abundance of dead wood, are the black woodpecker ( Dryocopus martius ) and stock dove ( Columba oenas ). An indication of the natural state of the beech woods in the Harz is the return of the black stork ( Ciconia nigra ). This shy and susceptible resident of richly diverse deciduous and mixed forest has become very rare in central Europe due to increasing disturbance of its habitat (caused by

6600-650: The building site, including scour protection for shoreline developments, improving rainwater in filtration through the use of permeable paving materials and grading away from structures, and inclusion of berms , wetlands or swales in the landscape. When more homes, shops and infrastructure are threatened by the effects of flooding, then the benefits of protection are worth the additional cost. Temporary flood defenses can be constructed in certain locations which are prone to floods and provide protection from rising flood waters. Rivers running through large urban developments are often controlled and channeled. Water rising above

6710-480: The capacity of stormwater systems. This separates stormwater from blackwater , so that overflows in peak periods do not contaminate rivers. One example is the SMART Tunnel in Kuala Lumpur. Some methods of flood control have been practiced since ancient times. These methods include planting vegetation to retain extra water, terracing hillsides to slow flow downhill, and the construction of floodways (man-made channels to divert floodwater). Other techniques include

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6820-486: The common beech gives way to hardier deciduous species such as sycamore, large-leaved lime ( Tilia platyphyllos ), Scots elm or ash. The herbaceous layer is similar to that of the better-nourished beech woods. Notable species amongst the plant communities here include the Alpine blue-sow-thistle ( Cicerbita alpina ), perennial honesty ( Lunaria rediviva ), hard shield fern ( Polystichum aculeatum ) and long beech fern ( Phegopteris connectilis ). The raised bogs in

6930-417: The construction of levees, lakes, dams, reservoirs, retention ponds to hold extra water during times of flooding. Many dams and their associated reservoirs are designed completely or partially to aid in flood protection and control. Many large dams have flood-control reservations in which the level of a reservoir must be kept below a certain elevation before the onset of the rainy/summer melt season to allow

7040-473: The context of natural hazards and disasters , risk management involves "plans, actions, strategies or policies to reduce the likelihood and/or magnitude of adverse potential consequences, based on assessed or perceived risks". Flood control , flood protection , flood defence and flood alleviation are all terms that mean "the detention and/or diversion of water during flood events for the purpose of reducing discharge or downstream inundation". Flood control

7150-568: The damage caused by flooding is to remove buildings from flood-prone areas, leaving them as parks or returning them to wilderness. Floodplain buyout programs have been operated in places like New Jersey (both before and after Hurricane Sandy ), Charlotte , North Carolina, and Missouri . In the United States, FEMA produces flood insurance rate maps that identify areas of future risk, enabling local governments to apply zoning regulations to prevent or minimize property damage. Buildings and other urban infrastructure can be designed so that even if

7260-399: The dams are primarily used to generate electricity , to provide drinking water , to prevent flooding and to supply water in times of scarcity. Modern dam-building began in the Harz with the construction of the Söse Valley Dam , which was built between 1928 and 1931. The dams of the Upper Harz lakes are some of the oldest dams in Germany that are still in operation. → See List of dams in

7370-466: The detrimental effects of flood waters. Flooding can be caused by a mix of both natural processes, such as extreme weather upstream, and human changes to waterbodies and runoff. Flood management methods can be either of the structural type (i.e. flood control) and of the non-structural type. Structural methods hold back floodwaters physically, while non-structural methods do not. Building hard infrastructure to prevent flooding, such as flood walls ,

7480-430: The drier hummocks and occasionally the cross-leaved heath ( Erica tetralix ) may be found. Typical grasses are the sheathed cottongrass ( Eriophorum vaginatum ), known for its bright, white clusters of fruit and deergrass ( Scirpus cespitosus ), which is rust-red in the autumn. One fascinating moorland plant is the round-leaved sundew ( Drosera rotundifolia ). Bog or northern bilberry (Vaccinium uliginosum) grows on

7590-427: The drier margins of the bog. A multitude of wild animals live in the beech forests of the Harz Mountains. Over 5,000 species, most of them insects, have their home in these woods. They include many species that help to decompose leaves and work them into the soil and ground cover, including springtails , oribatid mites , woodlice , roundworms , millipedes , earthworms and snails . Characteristic breeding birds in

7700-505: The earlier, serious destruction of the cave's features by Vandals . The first Harz 'rangers' were formed. In 1705, the last bear was killed in the Harz, on the Brocken. The steadily increasing consumption of wood by the pits and smelting works led to overexploitation of the forests and, from about 1700, to their outright destruction. There were no less than 30,000 charcoal piles in the Harz. In 1707, an order by Count Ernst of Stolberg forbade Brocken guides to take strangers or local folk to

7810-541: The effects of flood waters or high water levels during a flooding event. They include evacuation plans and rescue operations. Flood relief is part of the response and recovery phase in a flood management plan. Floods are caused by many factors or a combination of any of these generally prolonged heavy rainfall (locally concentrated or throughout a catchment area), highly accelerated snowmelt , severe winds over water, unusual high tides, tsunamis , or failure of dams, levees , retention ponds , or other structures that retained

7920-443: The fast recovery of individuals and communities affected, but their use remains limited. Flooding can occur in cities or towns as urban flooding . It can also take place by the sea as coastal flooding . Sea level rise can make coastal flooding worse. In some areas there are also risks of glacial lake outburst floods . There are many adaptation options for flooding: More frequent drenching rains may make it necessary to increase

8030-811: The flow", and deliberately flood some low-lying areas, ideally vegetated, to act as sponges, letting them drain again as the floodwaters go down. Excess water can be used for groundwater replenishment by diversion onto land that can absorb the water. This technique can reduce the impact of later droughts by using the ground as a natural reservoir. It is being used in California, where orchards and vineyards can be flooded without damaging crops, or in other places wilderness areas have been re-engineered to act as floodplains. In many countries, rivers are prone to floods and are often carefully managed. Defenses such as levees, bunds , reservoirs, and weirs are used to prevent rivers from bursting their banks. A weir, also known as

8140-441: The gate. A flood barrier , surge barrier or storm surge barrier is a specific type of floodgate , designed to prevent a storm surge or spring tide from flooding the protected area behind the barrier. A surge barrier is almost always part of a larger flood protection system consisting of floodwalls , levees (also known as dikes), and other constructions and natural geographical features. The self-closing flood barrier (SCFB)

8250-401: The high mountains of southern and eastern Europe. The waterways, with their distinct mountain stream character, play an important role right across the Harz. In comparison with the other natural regions of Lower Saxony, they are still very natural and varied, and the water is very clean. As a result of the high water velocity of the Harz streams, flowers rarely gain a foothold in the water. Even

8360-476: The higher regions are, as in most of the Harz, comparatively poor in nutrients and bases, so that only a few herbaceous plants occur here, such as heath bedstraw ( Galium saxatile ). For that reason it is more the ferns, mosses, lichens and fungi that, in addition to spruce trees, characterise these woods. Boulders and stone runs occur in the areas of weather-resistant rock in the high (alti-)montane and montane zones – these are extreme habitats for vegetation. Due to

8470-533: The hills lie the Cretaceous layers of the sub-Hercynian depression in the rolling hills of the Harz Foreland; south of the Harz, Permian sediments lie flat on southwest-dipping Palaeozoic beds. As a result of the northern fault zone and the vertical or, sometimes even overfolded, geological strata, the geology of the Harz sometimes changes frequently within a relatively small area of just a few square kilometres. As

8580-520: The human and socio-economic losses caused by flooding and is part of the larger field of risk management . Flood risk management analyzes the relationships between physical systems and socio-economic environments through flood risk assessment and tries to create understanding and action about the risks posed by flooding. The relationships cover a wide range of topics, from drivers and natural processes, to models and socio-economic consequences. This relationship examines management methods which includes

8690-526: The hummocks are preferred by Sphagnum magellanicum . The blanket of peat moss is penetrated by dwarf bushes such as cowberry and blueberry . Bog-rosemary ( Andromeda polifolia ) is a relict of the ice age. Other such ice age plants include the dwarf birch ( Betula nana ) and few-flowered sedge ( Carex pauciflora ). Cranberries ( Vaccinium oxicoccus ) bloom from May to June. The black crowberry ( Empetrum nigrum ) may also be seen amongst those bearing black fruit. Common heather (Calluna vulgaris) grows on

8800-531: The king's restricted forests . There were three restricted forests, so described, in the state of Saxony, where there was no longer unfettered access for everyone. This ban did not last forever. Mining, ironworks, water management, increasing settlement, woodland clearances, cattle driving, agriculture, and later tourism all undermined this imperial protection over the centuries. As early as 1224, monks who had settled in Walkenried bought extensive tracts of forest in

8910-496: The lack of soil material, only weak, straggly, very open spruce woods thrive here. They have an especially high variety of trees and allow more room of light-loving species such as silver birch, rowan, sycamore, willow and dwarf bushes such as the blueberry ( Vaccinium myrtillus ). Mosses and ferns are also common here. One unusual species is the Carpathian birch ( Betula pubescens subsp. carpatica ). Bog-spruce woods are found around

9020-422: The main drivers of floods interact with each other. Flood modelling combines factors such as terrain, hydrology , and urban topography to reproduce the evolution of a flood in order to identify the different levels of flooding risks associated with each element exposed. The modelling can be carried out using hydraulic models, conceptual models, or geomorphic methods. Nowadays, there is a growing attention also in

9130-427: The mouth of streams or small rivers, where an estuary begins or where tributary streams, or drainage ditches connect to sloughs . Tide gates close during incoming tides to prevent tidal waters from moving upland, and open during outgoing tides to allow waters to drain out via the culvert and into the estuary side of the dike. The opening and closing of the gates is driven by a difference in water level on either side of

9240-414: The near-natural habitat there are only a few, indigenous, genetically adapted ( autochthonous ) spruce trees. Wood-reed spruce woods dominate. A well developed ground vegetation thrives on their moderately rocky and fresh, but certainly not wet, soils, characterised in appearance especially by grasses such as shaggy wood-reed ( Calamagrostis villosa ) and wavy hair-grass ( Avenella flexuosa ). The soils in

9350-577: The negative side effects of mining in the Harz Mountains. In 1818, a mounted forester, Spellerberg, from Lautenthal, killed the last lynx in the Harz on the Teufelsberg. At the start of the 19th century, the increasing changes to the natural landscape wrought by man and the extinction of large mammals like the bear, wolf and lynx raised awareness of the threat to nature. Flood control Flood management describes methods used to reduce or prevent

9460-537: The oldest, first, deepest feelings of truth. On 23 March 1798, the last wolf was killed in the Harz near the Plessenburg. The count's guest house on the Heinrichshöhe had become too small and suffered from overcrowding; in 1799 it burned down. In 1800, a new guest house was built on the Brocken to replace it. Around 1800, large swathes of the Harz were deforested. The less resistant spruce monoculture, that arose as

9570-439: The path of floodwaters. Other solutions, such as HydroSack , are polypropylene exteriors with wood pulp within, though they are one-time use. There are several methods of non-structural flood management that form part of flood risk management strategies. These can involve policies that reduces the amount of urban structures built around floodplains or flood prone areas through land zoning regulations. This helps to reduce

9680-539: The production of maps obtained with remote sensing . Flood modelling is helpful for determining building development practices and hazard mitigation methods that reduce the risks associated with flooding. Stakeholder engagement is a useful tool for flood risk management that allows enhanced public engagement for agreements to be reached on policy discussions. Different management considerations can be taken into account including emergency management and disaster risk reduction goals, interactions of land-use planning with

9790-739: The raised bogs on marshy and boggy soils. In these sorts of places spruce woods can, in exceptional cases, also form the natural woodland in lower down the mountains. These wet, moorland woods have a high proportion of peat mosses ( Sphagnum spec. ). The ground vegetation may also have a rich proliferation of low bushes such as cowberry ( Vaccinium vitis-idaea ). Clumps of purple moor grass ( Molinia caerulea ) are also typical of this type of woodland habitat. The characteristic species of fungi in natural spruce woods are Phellinus viticola and prunes and custard ( Tricholomopsis decora ). Ravine ( Schluchtwald ), riparian ( Auwald ) and river source ( Quellwald ) woods only occur in small areas. In these places

9900-475: The rich food supplies of the mountain brooks. In 2000, the lynx was successfully reintroduced by the Harz National Park , and it has since fitted well into the ecology of the region. Through specific conservation measures in past years, the retreat of the bat population in the Harz has been halted. Amongst the mammals that may be hunted are the red deer , roe deer , wild boar and mouflon . The Harz

10010-557: The risk to people and property is through the production of flood risk maps. Most countries have produced maps which show areas prone to flooding based on flood data. In the UK , the Environment Agency has produced maps which show areas at risk. The map to the right shows a flood map for the City of York , including the floodplain for a 1 in 100-year flood (dark blue), the predicted floodplain for

10120-455: The river spreading over a floodplain) will slow some of the flow more than other parts, spreading the flow over time and blunting the spike. Even slightly blunting the spike significantly decreases the peak flood level. Generally, the higher the peak flood level, the more flood damage is done. Straight, clear, smooth concrete-walled channels speed up flow, and are therefore likely to make flooding downstream worse. Modern flood control seeks to "slow

10230-563: The silver mining industry in the Upper Harz and in Goslar. In the middle of the 14th century, the settlements in the Harz became heavily depopulated as a result of the Black Death , and a systematic resettlement of mining villages in the Upper Harz did not take place until the first half of the 16th century. In 1588, the Nordhausen doctor, Johannes Thal, published the first book on regional flora in

10340-462: The south Harz lies in the Thuringian district of Nordhausen. The Harz National Park is located in the Harz; the protected area covers the Brocken and surrounding wilderness area. Approximately 600,000 people live in towns and villages of the Harz Mountains. Because of the heavy rainfall in the region the rivers of the Harz Mountains were dammed from an early date. Examples of such masonry dams are

10450-432: The spike. Even slightly blunting the spike significantly decreases the peak flood level. Generally, the higher the peak flood level, the more flood damage is done. Modern flood control seeks to "slow the flow", and deliberately flood some low-lying areas, ideally vegetated, to act as sponges, letting them drain again as the floodwaters go down. Where floods interact with housing, industry and farming that flood management

10560-660: The spruce woods, more open beech forest with its higher population of small mammals in its search for food. For cover, however, it prefers the darker, denser spruce trees. A large number of the animals that live in natural spruce forest are suited to the special conditions of life in the higher parts of the Harz. Typical residents amongst the bird population include the crested tit ( Parus cristatus ), goldcrest and firecrest ( Regulus regulus and Regulus ignicapillus ), siskin ( Carduelis spinus ), treecreeper ( Certhia familiaris ), coal tit ( Parus ater ) and crossbill ( Loxia curvirostra ). Special mention should be made here of

10670-516: The stage about 250,000 years ago and hunted aurochs , bison , brown bear and cave bear , mammoths , rhinos , horses , reindeer , forest elephants and other animals in the Harz region. Tools used by Neanderthals were discovered inter alia in the Einhorn Cave in the southern Harz (100,000 years ago) and in the Rübeland Caves. Finds of birch pitch near Aschersleben on the northern edge of

10780-494: The stones, e. g. caddis fly larvae ( Trichoptera ) and snails , or can only live in the reduced water velocities on the bed of the stream or on stones by having flat body shapes, e. g. stonefly larvae. In the calmer parts of the stream, behind stones or in blankets of moss, there are also water beetles ( Hydrophilidae ) and small shrimp-like amphipods . Occasionally the golden-ringed dragonfly ( Cordulegaster boltoni ) and beautiful demoiselle ( Calopteryx virgo ),

10890-481: The sub-Hercynian phase (83  mya ), when the northern edge was steeply tilted. This formed a fault zone on the northern border of the Harz (the Northern Harz Boundary Fault or Harznordrandverwerfung ). The Harz is a fault-block range, that rises abruptly from the surrounding lowlands in the west and northeast and gradually dips towards the south. It is dissected by numerous deep valleys. North of

11000-494: The town of Goslar , and mines became established in the following centuries throughout the mountains. During the Middle Ages , ore from this region was exported along trade routes to far-flung places, such as Mesopotamia . The wealth of the region declined after these mines became exhausted in the early 19th century. People abandoned the towns for a short time, but prosperity eventually returned with tourism. Between 1945 and 1990,

11110-577: The two largest: the Oker Dam and the Rappbode Dam . The clear, cool water of the mountain streams was also dammed by early mountain folk to form the various mountain ponds of the Upper Harz waterways, such as the Oderteich . The 17 dams in the Harz block a total of twelve rivers. Because the Harz is one of the regions of Germany that experiences the most rainfall, its water power was used from early times. Today

11220-400: The water. Water levels during a flood tend to rise, then fall, very abruptly. The peak flood level occurs as a very steep, short spike; a quick spurt of water. Anything that slows the surface runoff (marshes, meanders, vegetation, porous materials, turbulent flow, the river spreading over a floodplain) will slow some of the flow more than other parts, spreading the flow over time and blunting

11330-461: The water. Flooding can be exacerbated by increased amounts of impervious surface or by other natural hazards such as wildfires, which reduce the supply of vegetation that can absorb rainfall. During times of rain, some of the water is retained in ponds or soil, some is absorbed by grass and vegetation, some evaporates, and the rest travels over the land as surface runoff . Floods occur when ponds, lakes, riverbeds, soil, and vegetation cannot absorb all

11440-458: The western Harz, to secure economically the one quarter of the Rammelsberg ore profits promised to them by Frederick Barbarossa in 1129. From that it can be deduced that there was already a shortage of wood then. From the 12th to the 14th centuries, large parts of the Harz were managed economically by the Cistercian Abbey of Walkenried . As well as agriculture and fishing, they also controlled

11550-520: The world, Silva hercynia , in which he described the flowers specific to the Harz. In 1668, Rudolph Augustus, Duke of Brunswick-Lüneburg granted the first conservation order for Baumann's Cave . The ducal decree stated, inter alia , that the cave should be permanently preserved by all those responsible as a special, natural wonder. It also stated that nothing should be spoiled or destroyed, and that groups of ordinary strangers should not be allowed to enter without prior arrangement. A resident mine worker

11660-500: The world, due to the absence of public accessibility, technical writing and data, and lack of easy-to-understand information. However, revived attention towards flood mapping has renewed the interest in enhancing current flood mapping for use as a flood risk management method. Flood modelling is a tool used to model flood hazard and the effects on humans and the physical environment. Flood modelling takes into consideration how flood hazards, external and internal processes and factors, and

11770-419: The worst floods in recent U.S. history having cost billions of dollars. Property owners may fit their homes to stop water entering by blocking doors and air vents, waterproofing important areas and sandbagging the edges of the building. Private precautionary measures are increasingly important in flood risk management. Flood mitigation at the property level may also involve preventative measures focused on

11880-437: Was entrusted to oversee the natural monument . Until the issue of this conservation order, there had only been an order for the protection of the forest, which had been issued by the ruling princes for real, practical considerations. But for the first time the 1668 cave order took ethical-aesthetic considerations into account. The year 1668 was the birth of classic nature conservation in the Harz. The order had been precipitated by

11990-476: Was first mentioned as Hartingowe in an 814 deed by the Carolingian King Louis the Pious . Settlement within the mountains began only 1000 years ago, as in ancient times dense forests made the region almost inaccessible. The suffix -rode (from German : roden , to stub) denotes a place where woodland had been cleared to develop a settlement. The year 968 saw the discovery of silver deposits near

12100-525: Was sufficient food to support it (insects, small mammals and small birds) as well as standing dead wood (spruce trees with woodpecker holes). In addition to the many species of birds, there is a range of large butterflies in the various spruce woods that, outside of the Harz, are seriously endangered or simply non-existent. Two species will be mentioned here as examples. Gnophos sordarius occurs in old, open wood-reed spruce forest, sometimes in connection with stone runs or bog spruce forests; Enthephria caesiata

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