Toddbrook Reservoir
| Toddbrook Reservoir | |||||||||
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| Coordinates | 53 ° 19 ′ 30 ″ N , 1 ° 59 ′ 37 ″ W | ||||||||
| Data on the structure | |||||||||
| Construction time: | 1837-1840 | ||||||||
| Height of the barrier structure : | 24 m | ||||||||
| Height of the structure crown: | 187.3 m | ||||||||
| Crown length: | 310 m | ||||||||
| Crown width: | 5 m | ||||||||
| Operator: | Canal & River Trust | ||||||||
| Data on the reservoir | |||||||||
| Altitude (at congestion destination ) | 181.8 m | ||||||||
| Reservoir length | 1 km | ||||||||
| Reservoir width | 200 m | ||||||||
| Total storage space : | 1 288 000 m³ | ||||||||
| Catchment area | 17 km² | ||||||||
The Toddbrook Reservoir is a reservoir in England .
description
The reservoir is located in Derbyshire in High Peak County , near the small town of Whaley Bridge . It is fed by the Todd Brook river , which also forms the outflow of the reservoir and flows into the Goyt River about 100 meters behind the dam . The dam was originally built to supply water to the Peak Forest Canal , Ashton Canal and Macclesfield Canal . Today the lake is also used for recreational activities such as sailing and fishing .
The dam consists of a mixture of boulder clay with sand and gravel. This material was obtained on site in the storage space. The core of the dam consists of impermeable clay, which is about 4.8 meters wide at the base and tapers to 3.3 meters towards the top of the dam.
Nature reserve
The reservoir decreases in size during dry periods and exposes large areas of mud. During the winter it usually backs up again completely. This means that the area periodically provides habitat for short-lived mosses such as Pseudephemerum nitidum , Physcomitrella patens , Riccia sorocarpa , Blasia pusilla and the rare Physcomitrium sphaericum . The area of the reservoir is a breeding area for around 30 different bird species such as great crested grebes and mallards and is used by other water birds such as teal and pochard as a feeding place and wintering area. Therefore, the area of the reservoir was placed under protection as a Site of Special Scientific Interest .
history
Two attempts to build a dam 150 and 250 meters upstream respectively failed in 1835 and 1837 because of poor soil conditions and mining activities. In 1840 the dam that exists today was completed. Since 1880 there have been reports of water ingress from the reservoir into pit buildings of the coal mining in the area.
Seepage water
In 1930, leaking water was observed at the foot of the dam. During the search for the cause in 1931, a deepening was discovered on the water side of the dam and filled.
In November 1975, when the water level was low, the depression in the dam that had appeared in 1931 was observed again. By autumn 1977 it had deepened again by 12 centimeters compared to 1975. The reservoir was then emptied and a crater-shaped depression four meters in diameter was found at the foot of the dam. Further investigations finally discovered in 1981 a brick, 1.2 meter wide passage under the dam . He had probably during construction as dewatering served and now represented a pre-drawn seepage. The site was sealed in 1983, the reservoir was full jammed again.
Overflow damage
In December 1964, due to heavy rainfall, the water level was above the overflow threshold of the canal for flood relief for three days . This resulted in damage to the overflow channel, parts of the side walls broke away and erosion occurred on the embankment. As a consequence of the spillway in 1969 to a 76 meter wide overflow weir extends from concrete, its overflow threshold located 26 cm above that of the first overflow channel, and has completed the 1970th
Maintenance work
In 2010 the storage space was emptied again to overhaul inlet pipes and valves for the water supply of the Peak Forest Canal and to carry out repair work on the dam. At the beginning of 2011 the reservoir was dammed again.
Dam damage 2019
After heavy rain from July 27, 2019 in the wake of the second European heat wave of the year , the weir started on July 31. On the morning of August 1, a concrete slab of the overflow channel fell into a cavity that had formed below in the softer dam material. During the day, more concrete slabs came loose and the overflowing water washed out more material. As a dam had to be feared, 400 of these potentially threatened houses were evacuated. With a Chinook helicopter of the Royal Air Force the eroded parts of the dam were carried big bags reinforced with a mixture of sand, gravel and crushed stone. In the same way, the inlet was blocked and the water was diverted around the reservoir in a bypass channel.
The water level was lowered by over nine meters in the following days by fire brigades using high-performance pumps. On the afternoon of August 7, the approximately 1,500 people affected by the evacuation were able to return to their homes.
An independent expert investigation into the incident was ordered. This came to the conclusion that the overflow weir was poorly designed and insufficient for an assumed maximum flood. Due to inadequate maintenance work, water could seep under the concrete slabs of the channel over the years and wash out material. The combination of these factors was ultimately decisive for the destruction of the overflow channel.
Web links
supporting documents
- ^ What's the history of the damaged Toddbrook Reservoir threatening Whaley Bridge? In: itv.com . August 1, 2019, accessed on August 2, 2019.
- ↑ Ian Littlechilds, Phil Page: From Bugsworth to Manchester: A History of the Limestone Trail . Amberley Publishing Limited, 2015, ISBN 978-1-4456-4060-0 ( limited preview in Google Book Search).
- ^ A b J. Andrew Charles, Paul Tedd, Alan Warren: Delivering benefits through evidence. Lessons from historical dam incidents . Ed .: Environment Agency. Bristol 2011, ISBN 978-1-84911-232-1 , pp. 124 f., 140 ( online at gov.uk.).
- ↑ a b c d e f David Balmforth: Toddbrook Reservoir: Independent Review Report. (PDF; 7.68 MB) In: service.gov.uk . February 10, 2020, accessed on July 5, 2020.
- ↑ 1001257: Site Notified to the Secretary of State on October 20, 1986. In: naturalengland.org.uk . Retrieved on August 2, 2019 (English; PDF; 4.3 kB).
- ^ Peter J Whitehead: The Reservoirs of the Peak Forest Canal - a Timeline. In: bugsworthbasin.org . Retrieved September 25, 2019.
- ↑ Todd Brook Reservoir refilling to start in new year. In: whaleybridge.com . January 5, 2011, accessed August 2, 2019.
- ^ Whaley Bridge dam collapse: RAF Chinook brought in. In: bbc.com . August 2, 2019, accessed on August 2, 2019.
- ↑ Peak District town evacuated as dam threatens to burst. In: theguardian.com . August 2, 2019, accessed on August 2, 2019.
- ^ Nazia Parveen: Whaley Bridge residents refusing to evacuate put lives at risk, says police chief. In: theguardian.com . August 4, 2019, accessed August 5, 2019.
- ^ Whaley Bridge dam: Residents wait to hear if they can return. In: bbc.com . August 7, 2019, accessed on August 7, 2019.
- ^ Whaley Bridge dam: Evacuated residents can return home. In: bbc.com . August 7, 2019, accessed on August 7, 2019.
- ↑ Water pumped out - dam breakage prevented. tagesschau.de , August 7, 2019, accessed on July 16, 2020 .
- ↑ Caroline Lowbridge: Whaley Bridge reservoir collapse: Lack of maintenance 'exacerbated' problem. In: bbc.com . March 16, 2020, accessed on July 5, 2020.