Balancing lake

Short description: Element of flood management system

Priorslee Lake in Shropshire, England. Originally known locally as the Balancing Lake, it was created to manage water run-off from the roofs and streets of Priorslee.

A balancing lake (also flood basin or Sustainable urban drainage scheme) is a term used in the U.K. describing a retention basin used to control flooding by temporarily storing flood waters.[1]:Glossary The term balancing pond is also used, though typically for smaller storage facilities for streams and brooks.

In open countryside, heavy rainfall soaks into the ground and is released relatively slowly into watercourses (ditches, streams, rivers). In an urban area, the extent of hard surfaces (roofs, roads) means that the rainfall is dumped immediately into the drainage system. If left unchecked, this will cause widespread flooding downstream. The function of a balancing lake is to contain this surge and release it slowly.[1]:Part E Failure to do this, especially in older settlements without separate storm sewers and foul sewers, can cause serious pollution as well as flooding.

## Contents

* 1 Engineering
* 2 Other benefits
* 2.1 Case study: Willen Lake, Milton Keynes
* 3 See also
* 4 References
* 5 Further reading

## Engineering

At its simplest, a balancing lake can be constructed by creating a dam across a drain or stream at a convenient valley, with a restricted diameter outlet pipe through the dam. Normal flows are carried happily through the pipe, but heavy flows back up and the water behind the dam is choked back. Over the following few days, the level subsides. This is often enough for a small housing development.

More advanced systems are computer-controlled such that the entire flow of a river can be diverted into a holding lake, perhaps to reduce the impact of a large scale rainstorm in the catchment on communities downriver.

For aesthetic and safety reasons, the system can be designed so that there is a permanent lake. A lake with an equivalent area of 1,000 by 1,000 metres will hold a million cubic metres of water for each metre of depth. Typically such a lake would have an outer earth bank of 1 metre, then a leisure path, then a 10 cm inner bank to the steady-state level.

## Other benefits

A permanent lake can provide useful recreation facilities such as sailing, windsurfing, or of wildlife.[2] Water sports and wildlife habitats do not mix well, though a scheme can have both in linked basins where the recreational basin fills first and the wildlife basin is only used in exceptional conditions.

* A recreational use facility can have relatively steep banks (perhaps with a footpath inside the bank next to the permanent lake for aesthetics and safety). The water level can rise substantially without a significant increase in overall area.
* A basin that is intended for use by wildlife and for visual amenity needs to be relatively shallow for maximum plant life. It must be designed with the assumption that it will be invoked very rarely, especially during the nesting season.

### Case study: Willen Lake, Milton Keynes

Willen Lake (north basin), with spill-way in the background

Willen Lake ( [ ⚑ ] 52°03′25″N 0°43′10″W﻿ / ﻿52.05694°N 0.71944°W﻿ / 52.05694; -0.71944) is one of the largest (400,000 m²) purpose-built stormwater balancing lakes in the UK. The lake is designed to take surface run-off from Milton Keynes, the largest of a number designed to do so. The lake has capacity for an additional level increase of 1.3 metres, equivalent to a once in 200 years event. Unlike most of the rest of the UK, the city has separate storm and foul sewers, so sewage pollution is not a significant problem.

Additionally, there are facilities to prevent accidental oil spills and the like from reaching the lake. As well as local storm drains, the lake's primary purpose is to intercept the river Ouzel, a tributary of the river Great Ouse. The catchment area is Oxford Clay that tends to get saturated easily, so field run-off has always been a problem.

The South Basin is designed for recreational use, mainly dinghy sailing and wind surfing, with a circumference path and banks as described above.[3] It is linked to the North (Wildlife) Basin and can be drawn on to manage the level of the latter more finely. The North Basin has a large, undisturbed, central island.[4] The extensive shallows support a good crop of aquatic plants and invertebrates. Very quickly, it became a key wildfowl site.

In winter, it attracts up to 2,500 wild birds, with a wide variety of migrating waders in spring and autumn. Common tern, tufted duck, ringed and little ringed plover, common redshank and northern lapwing.[5] Canada geese have become naturalised and they are permanent residents. Both basins have deep ponds to maintain the fish population during droughts. The lake is managed as a public open space, receiving up to a million visits each year.

## See also

* Stormwater
* Surface runoff
* Urban runoff
* Sustainable urban drainage systems
* Retention basin

## References

1. ↑ 1.0 1.1 "Milton Keynes Drainage Strategy – Development and Flood Risk: Supplementary Planning Guidance". Milton Keynes Council. May 2004. https://www.milton-keynes.gov.uk/assets/attach/4064/AdoptedFloodingSPGpdf.pdf.
2. ↑ Brown, Paul (23 April 2003). "Park land: The diverse and thriving green spaces of Milton Keynes belie its bland reputation". The Guardian. https://www.theguardian.com/society/2003/apr/23/guardiansocietysupplement3.
3. ↑ "Willen Lake South". Milton Keynes Parks Trust. https://www.theparkstrust.com/parks/willen-lake-south.
4. ↑ "Willen Lake Nouth". Milton Keynes Parks Trust. https://www.theparkstrust.com/parks/willen-lake-north.
5. ↑ "Willen Lake". Milton Keynes Natural History Society. 11 May 2021. https://mknhs.org.uk/willen-lake/.

## Further reading

* Wetlands, Industry & Wildlife: A manual of principles and practices. (1994) ISBN:0-900806-18-4 (The Wildfowl & Wetlands Trust, UK). Chapter 15.

* v
* t
* e

Ponds, Pools, and Puddles

Ponds|

* Ash pond
* Balancing lake
* Ballast pond
* Beel
* Cooling pond
* Detention pond
* Dew pond
* Evaporation pond
* Facultative lagoon
* Garden pond
* Ice pond
* Immersion pond
* Infiltration basin
* Kettle pond
* Log pond
* Melt pond
* Mill pond
* Polishing pond
* Raceway pond
* Retention pond
* Sag pond
* Salt evaporation pond
* Sediment pond
* Settling pond
* Solar pond
* Stepwell
* Stew pond
* Tailings
* Tarn
* Waste pond
* Waste stabilization pond

Pools|

* Anchialine pool
* Brine pool
* Infinity pool
* Natural pool
* Plunge pool
* Reflecting pool
* Spent fuel pool
* Stream pool
* Swimming pool
* Tide pool
* Vernal pool

Puddles|

* Bird bath
* Coffee ring effect
* Puddle
* Puddles on a surface
* Seep puddle

Biota|

* Beaver dam
* Duck pond
* Fish pond
* Goldfish pond
* Koi pond

Ecosystems|

* Aquatic ecosystem
* Freshwater ecosystem
* Lake ecosystem

Related|

* Aerated lagoon
* Bakki shower
* Big fish–little pond
* Body of water
* Constructed wetland
* Full pond
* Hydric soil
* Phytotelma
* Pond of Abundance
* Pond liner
* Ponding
* Puddle (M C Escher)
* Spring
* Swimming hole
* Water aeration
* Water garden
* Water Lilies (Monet)
* Well

* v
* t
* e

Rivers, streams and springs

Rivers|

* Alluvial river
* Braided river
* Blackwater river
* Channel
* Channel pattern
* Channel types
* Confluence
* Distributary
* Drainage basin
* Subterranean river
* River bifurcation
* River ecosystem
* River source
* Tributary
* more...

Streams|

* Arroyo
* Bourne
* Burn
* Chalk stream
* Coulee
* Current
* Stream
* Stream bed
* Stream channel
* Stream gradient
* Stream pool
* Perennial stream
* Winterbourne
* more...

Springs|

* Geyser
* Sacred spring
* Hot spring
* Karst spring
* Mineral spring
* Rhythmic spring
* Spring
* Spring horizon
* more...

Sedimentary processes
and erosion|

* Abrasion
* Anabranch
* Aggradation
* Armor
* Bed load
* Bed material load
* Granular flow
* Debris flow
* Deposition
* Dissolved load
* Downcutting
* Erosion
* Headward erosion
* Knickpoint
* Palaeochannel
* Progradation
* Retrogradation
* Saltation
* Secondary flow
* Sediment transport
* Suspended load
* Wash load
* Water gap

Fluvial landforms|

* Ait
* Alluvial fan
* Antecedent drainage stream
* Avulsion
* Bank
* Bar
* Bayou
* Billabong
* Canyon
* Chine
* Cut bank
* Estuary
* Fluvial terrace
* Gill
* Gulch
* Gully
* Glen
* Meander scar
* Mouth bar
* Oxbow lake
* Riffle-pool sequence
* Point bar
* Ravine
* Rill
* River island
* Rock-cut basin
* Sedimentary basin
* Sedimentary structures
* Strath
* Thalweg
* River valley
* Wadi

Fluvial flow|

* Helicoidal flow
* International Scale of River Difficulty
* Meander
* Plunge pool
* Rapids
* Riffle
* Shoal
* Waterfall
* Whitewater

Surface runoff|

* Agricultural wastewater treatment
* Effluent
* First flush
* Urban runoff
* Wastewater

Floods and stormwater|

* 100-year flood
* Crevasse splay
* Flash flood
* Flood
* Flood barrier
* Flood control
* Flood forecasting
* Flood-meadow
* Floodplain
* Flood pulse concept
* Flooded grasslands and savannas
* Storm Water Management Model
* Return period

River measurement
and modelling|

* Baer's law
* Baseflow
* Bradshaw model
* Discharge (hydrology)
* Drainage density
* Exner equation
* Groundwater model
* Hack's law
* Hjulström curve
* Hydrograph
* Hydrological modelling
* Hydrological transport model
* Infiltration (hydrology)
* Main stem
* Playfair's Law
* Relief ratio
* River continuum concept
* Rouse number
* Runoff curve number
* Runoff model (reservoir)
* Stream gauge
* Universal Soil Loss Equation
* WAFLEX
* Wetted perimeter
* Volumetric flow rate

River engineering|

* Aqueduct
* Balancing lake
* Canal
* Check dam
* Dam
* Drop structure
* Daylighting
* Detention basin
* Erosion control
* Fish ladder
* Floodplain restoration
* Flume
* Infiltration basin
* Leat
* Levee
* Retention basin
* Revetment
* Riparian zone restoration
* Stream restoration
* Weir

River sports|

* Canyoning
* Rafting
* River surfing
* Riverboarding
* Whitewater canoeing
* Whitewater kayaking
* Whitewater slalom

Other topics|

* Aquifer
* Aquatic toxicology
* Body of water
* Limnology
* Riparian zone
* River civilization
* River cruise
* Surface water
* World Rivers Day

Lists of rivers
Rivers by continent
Rivers by length
Rivers by discharge rate
Drainage basins
Whitewater rivers
Flash floods
River name etymologies

0.00

(0 votes)

Original source: https://en.wikipedia.org/wiki/Balancing lake. Read more

|

Retrieved from "https://handwiki.org/wiki/index.php?title=Earth:Balancing_lake&oldid=3298682"
*[v]: View this template
*[t]: Discuss this template
*[e]: Edit this template