DAMBREAK PROCEDURES

FIRST ACTION: DETERMINE IF THERE IS A WARNING OR WATCH OUT

Broken: Determine if the WFO has issued a generic Warning.

If not, advise that they do.

Not Broken: Determine if the WFO has issued a generic Watch.

If not, advise that they do.

SECOND ACTION: DETERMINE IF THE WFO HAS AN EMERGENCY ACTION PLAN (EAP) AVAILABLE

BY CHECKING DAM CATALOG FOR A 1 OR 2 IN EMERGENCY ACTION BOX

1=EAP AT WFO AND CBRFC, 2=EAP AT WFO ONLY, 0=NO EAP

***STOP! REFER TO EAP FOR ALL INFORMATION, DO NOT USE SIMPLIFIED DAM BREAK FORECASTS

2. IF EAP IS NOT AVAILABLE, GATHER INFORMATION FROM THE WFO OR OTHER CONTACT

Primary Information:

Name of Dam

Name of River

County

State

Check to see if we have an Emergency Action Plan available (mainly UT)

Secondary Information:

"NOTE: This information may be available in dam catalog!"

Water Surface elevation or depth (FT)

Height of Dam (FT)

Structure Type (Earth, Concrete)

Crest Length of Dam (FT)

Volume (AF)

Go to: Water -> Dambreak -> List

Using the primary information collected in step 2, and the station list, attempt to locate the dam information.

Topographic maps, aerial photos, soils, etc., are available for most dams on the web.

Also, if needed, USGS 30 x 60 quadrangle maps are available in the black file cabinet in alphabetical order. The dam catalog interface record has a field which tells you the name of the topo map, latitude and longitude, as well as other information. NOTE: These maps are in metric units.

In addition, we may have a limited set of more detailed 7.5 degree quad maps in the large gray map cabinet located in the store room (most of UT and some of AZ).

Option #1: Rules of Thumb

At the Dam:

(Depth of Water )

If the height of the water is known behind the dam, estimate the depth of the water at the breach to be ½ the depth of the water. If the water is near the top, or overtopping, estimate the height of the water at the breach to be ½ the height of the dam.

Downstream of the Dam at Forecast Point:

(Travel Time)

Steep slopes: 8-10 mph

Medium slopes: 5-7 mph

Shallow Channels: 2-4 mph

(Depth of Water)

There is no easy rule of thumb in estimating depth at some distance X from the dam.

Option #2: Using a Precomputed Scenario

-Click on: Water -> Dambreak -> List

-Find the dam in question by searching the appropriate field. (e.g., Search By: Dam/ River/ etc)

-Click on the highlighted 'ID' in the search list.

-Click on 'Model Run' in the line: View: Record/ Model Run

-Click on the Scenario desired, e.g., High Fast / High Normal / etc. in the line: Scenario: High Fast / High Normal/ ...

-Click on Real in the line: Mode: Test/ Real

-Scroll down and click on 'Save'

Option #3: Run Simplified Dambreak Model Using Prismatic Cross Section at

-Click on: View -> Model Run

NOTE: The forecast product will automatically be generated.(If you want to view the raw model output, Go to: Output Source -> Run Model -> Display -> Raw Model Output)

-Choose an applicable scenario (For more detailed information Go to:Homepage -> Water -> Dambreak -> Dambreak Prebreak Info) and/or check the inputs table (Click on: Table -> Inputs)

-Choose input from database or customize the input

-Edit the forecast product and add comments as appropriate.

-Change Mode to Real (Test is the default)

-Save

-Print and Send

Wait a few minutes, then check AWIPS to make sure the product was sent!

Relay the Forecast by Telephone:

Because of the time criticality in a dambreak situation, you should place a

telephone call to the WFO and relay your forecast information.

References:

o Home Page: Station Duty Manual

o NWS WR Supplement 18-29-02 Responsibilities Related to Dam Failures