Changes

Water Portal / Rainwater Harvesting / Surface water / Tyrolean weir

2,232 bytes added, 04:56, 22 October 2017

no edit summary

{{Language-box|english_link=Water Portal / Rainwater Harvesting / Surface water / Tyrolean weir | french_link= Coming soon | spanish_link= Toma Tirolesa | hindi_link= वाटर पोर्टल / वर्षाजल संचयन / सतही जल / टाइरोलीन मेड़ | malayalam_link= Coming soon | tamil_link= Coming soon | korean_link= Coming soon | chinese_link=提洛尔堰 | indonesian_link= Bendungan Tyrolean | japanese_link= 水のポータルサイト／雨水貯留／表面水／チロリアン式堰 }} [[Image:tyrweirTyrolean_weir_icon.jpgpng|right|80px]][[Image:Tyrolean weir.JPG|thumb|right|150px200px|Tyrolean weir|Man checking the grid at a Tyrolean weirWeir. Tanzania. Photo: D. Bourman, TanzaniaAqua for All.]] A '''Tyrolean weir''' is a water inlet structure in which water is abstracted from the main flow through a screen over a gutter. The gutter is usually made of concrete and built into the river bed. The screen on the crest should slope downstream (15-30 degrees), to increase flow velocities and prevent sediment carried by the stream from blocking it. From the gutter, water enters a pipeline, which drains into a sedimentation tank and then flows by gravity into the rest of the system.  Dams and water inlet structures in embankments are vulnerable and expensive elements in river-fed water systems. They are easily damaged by floods, underflow, seepage and suffer from build-up of sediment or rubbish in the water. The Tyrolean weir forms a more reliable and cheaper alternative.  ===Suitable conditions ===Tyrolean intakes are used in small permanent rivers and streams where the sediment content and bed load transport are low, or on the crest of a dam spill. The weir or intake should be carefully sited.  The weir itself does not clean or purify the water.

Dams and water inlet structures in embankments are vulnerable and expensive elements in river-fed water systems. They are easily damaged by floods, underflow, seepage and suffer from build-up of sediment or rubbish in the water. The Tyrolean weir forms a more reliable and cheaper alternative. Water is abstracted through a screen (or inlet) over a gutter, usually made of concrete and built into the riverbed. The screen on the crest should slope downstream (15-30 degrees), to increase flow velocities and prevent sediment carried by the stream from blocking it. From the gutter, water enters a pipeline, which drains into a sedimentation tank and then flows by gravity into the rest of the system.

{| border="1" cellpadding="5" cellspacing="0" align="center"

|-

! width="50%" style="background:#efefef;" | Advantages

! style="background:#ffdeadf0f8ff;" | Disadvantages

|-

| valign="top" | - More reliable and cheaper compared to dams and water inlet structures in river embankments<br>- They do not affect water flow to communities downstream| valign="top" | <br>- None known

|}

== Costs ==

* Material ===Resilience to changes in the environment=== ====Drought effects on cement===='''Effects of drought:''' Badly made concrete or cracked linings (excluding the pipe e.g. in tanks, dams, waterways, wells, and sedimentation tankother structures): US$ 300 - 600. <br>* Labour (if site is easily accessible)'''Underlying causes of effects: 30 - 50 man days''' Less water used for curing; Impure water used for mixing.<br>* Operation and maintenance'''To increase resiliency of WASH system: several visits per year for inspection''' Ensure adequate mixing, ratios, cleaning and minor repairs. Overall easy to carry out due to low-tech structure and the use purity of local labour and materialsingredients; Minimize water content in mixture; Ensure adequate curing.

== Applying conditions ==More information on managing drought: [[Resilient WASH systems in drought-prone areas]].

* Tyrolean intakes are used in small permanent rivers ===Construction, operations and streams where the sediment content and bed load transport are low, or on the crest of a dam spill. maintenance===* The threshold can be a concrete elevation above the rocky bed of a mountain stream, or a vertical low [[Image:Tyro weir structure, anchored in the embankment. * The capacity of the inlet pipe / drain (diameter and gradient) should be 30% more than the design flow and have an uniform gradient jpg|thumb|right|200px|Tyrolian weirs are meant to prevent accumulation of sandintake water from mountain rivers that are very turbulent.* The sedimentation tank can accumulate 1Photo: [http://www.5-2 m3 of deposits and allows water to filter for 10 to 30 minutes at very low speedtuwien. It is cleaned by washing it outac.at/en/tuwien_home/ Vienna University of Technology]]]

A Tyrolean weir can either consist of parallel rods or a perforated plate, installed in the flow direction over the width of the stream with a 15-30 degree downward slope. Large stones, branches and large leaves cannot pass between the rods, and are prevented from entering the gutter. Because the rods / plate slopes downward, the material in the stream is pushed downstream, until it drops over the end of the weir.

== Considerations ==The threshold can be a concrete elevation above the rocky bed of a mountain stream, or a vertical low weir structure, anchored in the embankment. The capacity of the inlet pipe / drain (diameter and gradient) should be 30% more than the design flow and have an uniform gradient to prevent accumulation of sand. The sedimentation tank can accumulate 1.5-2 m³ of deposits and allows water to filter for 10 to 30 minutes at very low speed. It is cleaned by washing it out.

* The weir or intake should be carefully sited====Maintenance====Several visits per year to the site are necessary for inspection, cleaning and minor repairs. * The weir itself does not clean or purify Overall, maintenance is easy to carry out due to low-tech structure and the wateruse of local labour and materials.

== Maintenaince ==Regular inspection and cleaning of the grit / rack and possibly the gutter and sedimentation tank is required during and after storm periods.

===Costs===* Regular inspection and cleaning of Material (excluding the grit / rack and possibly the gutter pipe and sedimentation tank ): US$ 300 - 600. * Labour (if site is required during and after storm periodseasily accessible): 30 - 50 man days.

===Manuals, videos and links===

* [http://www.samsamwater.com/library/TP40_11_Surface_water.pdf Surface water intake and small dams]. Chapter 11. Revised by Nhamo Masanganise.

== External links =Acknowledgements===* General Background CARE Nederland, Desk Study: [http://www[Resilient WASH systems in drought-prone areas]].aquaforallOctober 2010.nl www.aquaforall.nl]

• ← Older edit

Eight star

Emailconfirmed

224

edits