ASDSO Dam Safety Toolbox

Wave Runup: Difference between revisions

From ASDSO Dam Safety Toolbox
Jump to: navigation, search
(Created page with "__NOTOC__ ---- <!-- Delete any sections that are not necessary to your topic. Add pictures/sections as needed --> “Estimates of maximum wave runup on rough, impermeable sloping structures (riprap revetments) are necessary to determine whether overtopping will occur for a specified wave condition and water level. Design formulas were originally developed based on theory and small-scale laboratory experiments using regular waves. As laboratories acquired the capability t...")
 
No edit summary
 
(3 intermediate revisions by 2 users not shown)
Line 1: Line 1:
__NOTOC__
__NOTOC__
[[Category:Flood]]
----
----
<!-- Delete any sections that are not necessary to your topic. Add pictures/sections as needed -->
<!-- Delete any sections that are not necessary to your topic. Add pictures/sections as needed -->
“Estimates of maximum wave runup on rough, impermeable sloping structures (riprap revetments) are necessary to determine whether overtopping will occur for a specified wave condition and water level. Design formulas were originally developed based on theory and small-scale laboratory experiments using regular waves. As laboratories acquired the capability to generate more realistic irregular waves, improved wave runup formulas were proposed based on wave parameters representative of the irregular wave train. However, unlike regular waves that result in a single value of maximum wave runup, irregular waves produce a runup distribution. Thus, it was necessary for the runup formulas to determine a representative parameter of the wave runup distribution. Presently, the most common irregular wave runup parameter is '''R<sub>u2%</sub>'''. This parameter is defined as the vertical distance between the still-water level (swl) and the elevation exceeded by 2 percent of the runup values in the distribution. In other words, for every 100 waves running up a slope, two waves would have a runup elevation exceeding the level estimated by '''R<sub>u2%</sub>'''”.<ref name="CHETN-III">[[Estimating Irregular Wave Runup on Rough, Impermeable Slopes (ERDC-CHL CHETN-III) | ERDC-CHL CHETN-III Estimating Irregular Wave Runup on Rough, Impermeable Slopes, USACE, 2005]]</ref>
"Experience has shown that [[Embankment Dams|embankment dams]] with large [[reservoirs]] and long fetches can be subject to the buildup of very large waves that could run high up on the upstream slope. Dam crests can be damaged and [[Embankment Dams|embankment dams]] can possibly fail by wave action even before they would be subject to flood overtopping. Some small dams have been damaged as well. Splash and spray over a dam crest is not uncommon when high velocity winds occur over high reservoir water surfaces. Hurricanes can produce this damaging combination because high velocity winds can persist through the peak reservoir levels. Wind and wave action have long been considered significant factors in the determination of the design crest elevation (not including camber) of an embankment dam and the analysis of all types of freeboard."<ref name="Ch6">[[Design Standards No. 13: Embankment Dams (Ch. 6: Freeboard)| Design Standards No. 13: Embankment Dams (Ch. 6: Freeboard), USBR, 2012]]</ref>
 
"Wind-generated wave heights and wave runup are probably the most thoroughly studied and understood factors that influence freeboard. Much of the study has been carried out and reported by the [[U.S. Army Corps of Engineers]]. Wave generation is influenced by wind characteristics such as velocity, duration, and orientation with respect to the reservoir; by topographic configuration of the reservoir, including depth and shoaling effects; and by fetch. Fetch accounts for the effects of the length of the open-water approach of the waves. Wave runup is governed by the height and steepness of the waves; by the slope, roughness, and porosity of the dam face; by changes in the slope of the dam face; and by the presence of berms on the dam face. Setup is caused by the shearing effect of the wind that tends to tilt the reservoir higher in the direction of the wind."<ref name="Ch6" />


==Examples==
{{Website Icon}}
==Best Practices Resources==
==Best Practices Resources==
{{Document Icon}} [[Estimating Irregular Wave Runup on Rough, Impermeable Slopes (ERDC-CHL CHETN-III)]]
{{Document Icon}} [[Design Standards No. 13: Embankment Dams (Ch. 6: Freeboard)|Design Standards No. 13: Embankment Dams (Ch. 6: Freeboard), USBR]]
{{Document Icon}} [[Hydrologic Engineering Requirements for Reservoirs (EM 1110-2-1420)|Hydrologic Engineering Requirements for Reservoirs (EM 1110-2-1420), USACE]]
 
==Trainings==
==Trainings==
{{Video Icon}}
{{Video Icon}} [[On-Demand Webinar: Designing Slope Protection for Dams and Levees]]


<!-- For information on notation for in text citations visit https://www.mediawiki.org/wiki/Help:Cite  Or simply enclose the citation as shown <ref> citation </ref> in the location of the in text mention. Citations will automatically populate below-->
<!-- For information on notation for in text citations visit https://www.mediawiki.org/wiki/Help:Cite  Or simply enclose the citation as shown <ref> citation </ref> in the location of the in text mention. Citations will automatically populate below-->

Latest revision as of 04:35, 21 July 2023


"Experience has shown that embankment dams with large reservoirs and long fetches can be subject to the buildup of very large waves that could run high up on the upstream slope. Dam crests can be damaged and embankment dams can possibly fail by wave action even before they would be subject to flood overtopping. Some small dams have been damaged as well. Splash and spray over a dam crest is not uncommon when high velocity winds occur over high reservoir water surfaces. Hurricanes can produce this damaging combination because high velocity winds can persist through the peak reservoir levels. Wind and wave action have long been considered significant factors in the determination of the design crest elevation (not including camber) of an embankment dam and the analysis of all types of freeboard."[1]

"Wind-generated wave heights and wave runup are probably the most thoroughly studied and understood factors that influence freeboard. Much of the study has been carried out and reported by the U.S. Army Corps of Engineers. Wave generation is influenced by wind characteristics such as velocity, duration, and orientation with respect to the reservoir; by topographic configuration of the reservoir, including depth and shoaling effects; and by fetch. Fetch accounts for the effects of the length of the open-water approach of the waves. Wave runup is governed by the height and steepness of the waves; by the slope, roughness, and porosity of the dam face; by changes in the slope of the dam face; and by the presence of berms on the dam face. Setup is caused by the shearing effect of the wind that tends to tilt the reservoir higher in the direction of the wind."[1]

Best Practices Resources

Design Standards No. 13: Embankment Dams (Ch. 6: Freeboard), USBR

Hydrologic Engineering Requirements for Reservoirs (EM 1110-2-1420), USACE

Trainings

On-Demand Webinar: Designing Slope Protection for Dams and Levees


Citations:


Revision ID: 7354
Revision Date: 07/21/2023