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| − | =Thur = | + | =Thur= |
| − | <googlemap version="0.9" lat="47.591896" lon="8.761382" zoom="16" scale="yes" overview="yes" controls="large">
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| − | 47.589098, 8.760438, test
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| − | ksjdf fjk gdjkf gdf
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| − | [[Pressures]]
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| − | 6#B2758BC5
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| − | 47.589222, 8.760996
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| − | 47.5893, 8.762476
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| − | 47.589213, 8.765845
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| − | 47.589966, 8.766575
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| − | 47.592817, 8.766232
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| − | 47.59299, 8.763978
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| − | 47.59315, 8.76194
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| − | 47.593164, 8.759108
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| − | 47.593222, 8.75694
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| − | 47.59315, 8.755116
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| − | 47.593048, 8.7537
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| − | 47.593019, 8.752456
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| − | 47.591905, 8.752069
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| − | 47.590458, 8.752134
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| − | 47.590024, 8.754215
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| − | 47.590516, 8.769321
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| − | </googlemap>
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| | | | |
| − | {{forecasterTemplate
| + | <googlemap version="0.9" lat="47.5919253276985" lon="8.76691818237305" zoom="13" width="100%" height="400" scale="yes" overview="yes" toc="no" controls="large"> |
| − | |site_name=Thur
| + | (A) 47.5919253276985, 8.76691818237305</googlemap> |
| − | |river_name=Thur
| + | |
| − | |river_type_name=large slow-flowing river over sand/clay
| + | |
| − | |country=CH
| + | |
| − | |altitude=high: > 800 m
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| − | |catchmentarea=large: > 1000 - 10000 km2
| + | |
| − | |geology=Calcareous
| + | |
| − | |latitude=47.5919253276985
| + | |
| − | |longitude=8.76691818237305
| + | |
| − | |natcode=XXX
| + | |
| − | |pressures=[[Morphological alterations]]<br> Channelisation/Cross section alteration<br>
| + | |
| − | |measures=Working with physical form and function of river and floodplains<br> River bed raising or lowering<br>Structural modifications<br> Construction of new structures<br> Modify/replace existing structures<br>Changes in system operation<br> Appropriate vegetation management plan<br>
| + | |
| − | |size=1
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| − | |size_unit=km2
| + | |
| − | |costs= 0
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| − | |costs_unit= EUR
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| − | |synergy=Flood control
| + | |
| − | |status_name= Realised
| + | |
| − | |period= 1999
| + | |
| − | |evaluation=Yes
| + | |
| − | |organization=
| + | |
| − | }}
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| | | | |
| − | '''Attention:'''The information presented below has been reproduced from the ECRR brochure<ref>ECRR brochure (click [http://www.ecrr.org/pdf/ecrrbrochure.pdf here] for online source)</ref>.
| + | <Forecasterlink type="getProjectInfoBox" code="22" /> |
| | + | |
| | + | ==Key features of the case study== |
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| − | <br>
| + | ==Site description== |
| − | The Thur river is one of the main rivers in the Cantons St. Gallen, Thurgau and Zürich in Switzerland. It has a lenght of 127 km and a catchment area of 1,750 km<sup>2</sup> with about 456 creeks and brooks. The highest point is the summit of Säntis at 2,551 masl. The 100 years flow is estimated at 1,350 m<sup>3</sup>/s, the lowest runoff is 2,24 m<sup>3</sup>/s, and the average flow is 47 m<sup>3</sup>/s. The Thur is a wild river with no lake or dam or big floodplain for retention.
| + | |
| | + | ==Measures selection== |
| | | | |
| − | The first flood control works were constructed in the second half of the 19th century. Today, the ancient dikes and other measures applied in the late 19th century no longer adequately cope with modern discharge conditions, mainly due to insufficient heights, inappropriate construction materials, and poor maintenance. The river bed has been filled with sediment deposits, limiting discharge capacity and increasing flood peaks, while the increased human occupation of the valley in some places limits the extent of the floodplain and interferes with surface roughness (trees) in others.
| + | ==Success criteria== |
| | | | |
| − | After the catastrophic flooding due to the breaking of the dikes in 1978, urgent response measures included the repairing and heightening of the dikes and the removal of
| + | ==Ecological response== |
| − | surface layer sediments from the confined stream bed. The increased attention paid to ecological aspects in later years resulted in a removal of the old stonewall parallel
| + | |
| − | to the stream bed, while groynes were build in combination with obliquely placed blocks and willow trees.
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| | | | |
| − | [[Image:Thur_river_before_after_photos.png|400px|thumb|left|Widening of the Thur river, Switzerland]]
| + | ==Hydromorphological response== |
| | | | |
| − | The resulting variety of river works provide both protection while allowing the river a greater freedom to spread and move. Over a length of 1,500 m and a width of 500 m
| + | ==Monitoring before and after implementation of the project== |
| − | the Thur river now can redevelop its natural course, in which erosion and sediment deposition processes freely alternate. Scours and rapids as well as wandering gravel | + | |
| − | beds have once again become a part of the river. This new design of the river was successfully tested by the flood of 1999 (Q 1,000m<sup>3</sup>/s), in which only a few blocks were moved downstream, and no extensive repairing appeared necessary.
| + | |
| | | | |
| − | The river restoration works also proved a great success for the ecological state of the Thur river. Fish species like the ''Chondrostoma nasus'' and bird species like the ''Actitis hypoleucos'' found new habitats within the new river landscape.
| + | ==Socio-economic aspects== |
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| − | The experiences with the river restoration project of the Thur river provide important perceptions for further projects on other rivers. More space for rivers gives opportunities to restore natural wild flora and fauna. Besides, the character of the river changes from a dull canal to a diversified river environment, offering opportunities for tourism and recreation. The Thur river restoration project shows that flood control by means of nature friendly technical river works not necessarily oppose nature conservation interests.
| + | ==Contact person within the organization== |
| − | | + | |
| − | '''References:'''
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| − | <references />
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| | | | |
| | + | ==Extra background information== |
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| | | | |
| | + | ==References== |
| | + | <references/> |
| | | | |
| | [[Category:Case_studies]] | | [[Category:Case_studies]] |
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| | + | == Related Measures == |
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| | + | <Forecasterlink type="getMeasuresForProject" code="22" /> |
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| | + | == Related Pressures == |
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| | + | <Forecasterlink type="getPressuresForProject" code="22" /> |
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| | + | [[Category:River depth and width variation]] [[Category:Structure and substrate of the river bed]] [[Category:Structure of the riparian zone]] [[Category:Fish]] |
