Klimadæmning ved Rathlousdal

Rathlousdaldæmningen efter et skybrud sent i maj 2021

Området vil Rathlousdal før etablering af jordvold og dæmning.

Sent i oktober 2020 begyndte arbejdet med at etablere selve dæmningen.

Forhøjet vandstand i reservoiret vest for dæmningen i februar 2021.

Dæmningen blev etableret for at reducere oversvømmelser som den hundredeårsoversvømmelse, der i 2018 efterlod Odder museum og store dele af Odder by under vand.

Intro

Klimaforandringer påvirker os alle og har bl.a. ført til kraftigere og hyppigere skybrud og oversvømmelser, som den der ramte Odder by d. 14. august 2018. Derfor etablerede Odder Kommune & Samn Forsyning i 2020 en klimadæmning ved Rathlousdal for at begrænse fremtidige oversvømmelser langs Odder Å.

'''Odder bys historie er i høj grad bundet til Odder Å, men klimaforandringer har bragt nye udfordringer til livet langs åen.'''

''Den tidlige byudvikling'' Odder var oprindeligt en forholdsvis stor by i nærheden af godset Rathlousdal. Oprindeligt hørte godset under Bygholm ved Horsens og gik under navnet Loverstrup. Godset brugte Odder Å som kraftkilde til en vandmølle ved navn Loverstrup Mølle, som desværre ikke står den dag i dag. Længere nedstrøms af Odder Å ligger endnu en opstemning af åen, og her har der været drevet vandmølle i mere end 400 år. Møllen har gennem tiden båret mange navne, såsom Tues Mølle, Sandager Mølle og Odder Overmølle, og har tjent som alt fra kornmølle til industrimølle. Mølleriet ophørte i 1955 og i dag holder Odder Museum til i møllen. Langs åen lå gårde og huse i en lang række. De fleste havde grund ned mod åen og adgangsvej fra Nørregade, Rosensgade, Tornøegade eller Østergade, der alle følger åens forløb og terrænet langs åen.

''Gang i byudviklingen'' Som byudviklingen tog fart i starten af 1900-tallet udviklede byen sig væk fra Odder Å og ud på de højereliggende arealer syd for åen. Odder Å mistede derfor sin betydning som kraftkilde for byen.

''Odder Å i dag'' I dag er Odder Å gemt lidt væk i bybilledet, men den kan dog stadig ses ved Hjertestien syd for Odder Rådhus og nord for Odder Kirke, hvor den løber gennem et græsklædt areal. Mølledammen ved Odder Museum er desuden bevaret, selvom møllen ikke er i brug længere. Ved åens indløb til Odder by har man konstrueret en dæmning, der skal reducere oversvømmelser fra åen. I de seneste år er man igen begyndt at få øjnene op for åens potentiale, og der bliver arbejdet på igen at gøre Odder å til et livgivende element i bybilledet i Odder.

'''Gennem historien har Odder Å oversvømmet mange gange, men i de senere år har klimaforandringerne gjort, at disse oversvømmelser er sket med tiltagende hyppighed.'''

''Hvorfor oversvømmer Odder Å?'' Odder Ås forløb gennem Odder by sker øst for et stejlt bakkelandskab. Når der falder store mængder regn, vil vandet løbe ned fra bakkelandskabet og samles i Odder Å. Regnen betyder desuden, at der kommer en øget vandmængde opstrøms for byen, og tilsammen vil dette få åen til at gå over sine breder. Klimaforandringerne gør at kraftige regnvejr sker oftere og med større intensitet. I de sidste 150 år er er den årlige nedbørsmængde steget med over 100 mm og den største stigning er sket i de seneste år. Konsekvenserne af de store vandmængder er voldsomme og klimaforandringerne stiller krav om langsigtet planlægning og omfattende handling fra kommune, stat - og borgere.

''Hundredeårsoversvømmelsen i 2018'' Den 14. august 2018 blev Danmark ramt af et voldsomt skybrud og værst gik det ud over området mellem Odder og Tranbjerg. Ved Fillerup vest for Odder blev der målt 115 mm regn mellem klokken 00 og 11, og vandstanden i Odder Å nåede her 1,4 m, 5-7 gange den normale vandstand og over 50 cm over den hidtil højeste målte vandstand. Også i Odder by kunne oversvømmelserne tydeligt mærkes. Store dele af Mølleparken stod under vand, og der var massive oversvømmelser i og omkring Odder Museum. Desuden stod vandet til langt op ad soklen af husene på Mejerivej, Rådhusgade og langs Mølleparken.

'''Klimaforandringer gør sig stærkt gældende i disse år. Skybrud og oversvømmelser sker med øget hyppighed og intensitet, og det giver udfordringer for livet langs Odder Å.'''

''Klimadæmning ved Rathlousdal'' For at begrænse oversvømmelserne af Odder Å etablerede Odder Kommune i samarbejde med Samn Forsyning en dæmning ved Rathlousdal, opstrøms for Odder by, i 2020. Dæmningen består af en 180 meter lang jordvold, der kan tilbageholde vandet fra Odder Å i et oversvømmelsesbassin i tilfælde af ekstremt nedbør. Odder Å løber midt i dæmningen, og omkring den har man etableret en vandbremse, der består af en stålplade monteret i et betonbygværk. Vandbremsen er udformet, så åen frit kan løbe igennem i normalsituationer, og så fisk og andre dyr frit kan passere den. I tilfælde af skybrud vil vandet stige opstrøms dæmningen og oversvømme et område på cirka 3,2 hektar i stedet for Odder by. Havde dæmningen eksisteret ved hundredeårsoversvømmelsen i 2018, ville bassinet kunne have tilbageholdt ca. 32000 af de 40000 kubikmeter vand, der oversvømmede Odder den dag. Klimadæmningen er det første af i alt 6 projekter, der skal være med til at sikre Odder by mod oversvømmelser i fremtiden.

''Climate Dam at Rathlousdal'' Climate change affects us all and has among other things led to more frequent and intense cloudbursts and floodings, like the one that hit Odder on august 14th 2018.As such Odder Kommune and Samn Forsyning established a climate dam at Rathlousdal in 2020 in order to limit future floodings along the stream, Odder Å.

''Odder Å'' The history of the city of Odder is highly linked to the stream Odder Å, but climate change has brought new challenges to life along the stream.'' '' '''''Early urban development''''' Odder was originally a relatively large town near the estate Rathlousdal. Originally, the estate belonged to Bygholm by Horsens and went under the name Loverstrup. The estate ude Odder Å as a power source for a water mill by the name og Loverstrup Mølle, which sadly no longer exists Further downstream along Odder Å lay another ponding of the stream, which has been home to a watermill for over 400 years.The mill has had many a name through the ages, such as Tues Mølle, Sandager Møle and Odder Overmølle, and has served as everything from a grain mill to an industrial mill. The milling stopped in 1955 and today the mill is home to Odder Museum. Houses and farms lay in a single file along the stream. Most houses had plots toward the stream and access from Nørregade, Rosensgade, Tornøegade or Østergade, which all follow the course of the stream and the surrounding terrain. '''''Speeding up urban development''''' As urban development really kicked off in the beginning of the 20th century, the town started developin away from Odder Å and out into the out onto the areas south of the stream. As such Odder Å lost its importance as a power source for the town. '''''Odder Å today''''' Today Odder Å has been hidden away in the city, but it can still be seen Hjertestien south of the town hall, and north of Odder Church. where it runs through a grassy area. The mill pond by Odder Museum has also been conserved even though the mill has long since been decommisioned. By the inlet of the stream to the city, a dam has been constructed designed to reduce flooding from Odder Å. In later years, people have once again begun to realize the potential of the stream and work is being done to restore Odder Å to its former status as a life giving element to the city.

''When the stream oveflows'' Throughout history Odder Å has flooded many time, yet in recent years climate change has caused these floodings to become more frequent. '''''Why does Odder Å flood?''''' Odder Å runs through the city of Odder just east of a steep hillscape. In the event of a cloudburst, the water will run down from the hillscape and collect in Odder Å. The rain will also cause an increased amount of water to flow into the city from upstream and together this will cause Odder Å to flood. Climate change causes heavy rainfall to happen more often and with greater intensity. In the last 150 years the annual rainfall in Denmark has increased by more than 100 mm, the greatest increase of which has happened in later years. The consequenses of these large amonut of water are severe and climate change demands longsighted planning and extensive action from municipality, state - and individual citizens.'' '' '''''The century flooding of 2018''''' On august 14th 2018, Denmark was struck by a powerful cludburst. Most affected were the areas between Odder and Tranbjerg. At Fillerup west of Odder 115 mm of rainfall was detected between midnight and 11 am, and the water level in Odder Å reached 1.4 m, 5-7 times the normal water level and 50 cm more than the previous record for highest water level in Fillerup. The effects of the flood were clearly felt in Odder as well. Large parts of Mølleparken were under water and there were massive floodings in and around Odder Museum. In addition, the water reached far up on the plinth of the houses on Mejerivej, Rådhusgade and along Mølleparken.

''The Dam'' Climate change has become highly relevant i later years. Cloudbursts and floodings are happening more often and more intensely, and that poses a challenge to life along Odder Å. '''''Climate dam at Rathlousdal''''' In order to limit the flooding of Odder Å, Odder Kommune in cooperation with Samn forsyning established a dam at Rathlusdal, upstream of Odder, in 2020. The dam consists of a 180 m long dike, which can hold back the waters from Odder Å in the event of heavy rainfall. Odder Å runs through the middle of the stream and around it a water brake, consisting of a steel plate set in a concrete frame, has been established. The water brake has been formed so the stream can run through it freely during periods without rain and so fish and other animals can pass freely though the brake. In the event of a cloudburst the water level will rise upstream of the dam and flood an area of about 3.2 acres in stead of Odder. Had the dam existed in 2018, the basin would have held back about 32000 of the 40000 cubic meters of water that flooded Odder that day. The climate dam is the first of a total of 6 projects design to help protect Odder from flooding in the future.

''Publiceret''