Dworshak Dam

Hello "Guest" - Lily ann - Orofino Elementary

I have looked at your local situation (North Fork of the Clearwater River) on "Google Earth", (Download that excellent free program from: http://earth.google.com/ install it to your computer, and you can see it for yourself), and see that Orofino township appears to be a pleasant location spread out in three separate locations along the banks of the river - I have probably looked at the roof of your own house.

The Google Earth software gives spot elevations of where your computer cursor is placed, and you can see the actual height above msl (mean sea level) at the centre bottom of the Google Earth picture, as "elev xxxx m" which height above msl varies as the cursor is moved "to various places in the map".

The Spot elevations are measured remotely from a satellite, and are quite accurate.

All measurements on Google Earth are Metric Measure.

Dworshak Dam:

All dams "leak water", and that "leaking water" is carefully monitored to ensure that it does not increase suddenly.

The Elevation of the concrete gravity dam reservoir is 488 metres above msl (mean sea level) while the tail-race (water exit) of the dam is 328 metres above msl.

This quickly gives the vertical height of the stored water as the difference between the two figures above, of 160 metres "head of water (526 ft head for you in the US).

This is quite a head of water, and plenty of it, because of the reservoir length.

The Dworshak dam is the highest straight-axis concrete dam in the Western Hemisphere and the 22nd highest dam in the world. Only two other dams in the United States exceed it in height.

If the dam failed, the result would be catastrophic for those in the water path, and in spite of the initial rush of that water pointing away from much or Orofino, the waters being suddenly released could not all go downstream instantly.

Thus the water would partly run back up the river valley towards Orofino, and some quick estimates would show that even Koncolville Motel, at the eastern end of upper Orofino would be covered with around 40 metres of water, in an initial dam burst.

So if you live in Orofino, there is not going to be time to "get up a tree", because within a minute or two, the banked up water would be over the heads of all in Orifino, and probably up the valley much further than the bridge at Greer.

In time, after the reservoir lost all the water, and it flowed away down the valley, the banked up water would recede, leaving a scene of devastation behind.

There is no real point in worrying about a possible dam failure, because if it happens, the process will be very quick.

Catastrophes - General:

There are many possible catastrophic scenarios, and I see Orofino is approximately 450km (280 miles) from the large super-volcano of Yellowstone, the caldera of which could collapse at any time, causing a "global winter over many years" for the whole Earth.

We do, of course, have a local super-volcano in New Zealand, the Taupo - White Island volcanic super-volcanic area, the collapse of that would also cause local devastation, along with several years "Global Winter", but I don't worry about it.

I live in Christchurch, New Zealand, which has been called "The Shaky Isles", because of the large number of earthquakes which occur throughout the country each day.

Thus a local fault is liable to result in a tsunami, the height of which could be 100 metres or more over my sleeping head.

The nearest major river, the Waimakariri, used to flow right through where the city of Christchurch now stands, and could quite easily flood through the city location once again.

Meteors, a plane crash, earthquakes, hurricanes, tornadoes, lightning, dam collapse, flood, fire-storm and more these things have always happened, and will continue while this special planet we live on remains.

Remember that nothing made only of material atoms is going to remain forever, it is just all so very temporary, but all people are designed to last for eternity.

So, the best thing to do, is to hope for the best, prepare for the worst, help others, and ensure that when you leave this planet, as we all must, you do go where a better place has been prepared for you, by God who loves you.

The most important thing in life is to remember that this part of your life on Earth is a place of choice for each person - we have been given freedom to choose good or evil.

So....I cannot offer you any useful ideas except the above.

Further:

If the reservoir dam does have cracks, there is little which can be done except to drain the reservoir manually, dismantle the present dam, and build a replacement, then refill the reservoir again.

During all that time, there would be the loss of electricity generation from the powerhouse as included in to the losses.

All the above operation is going to take at least five years, but because of the huge costs involved, this is replacement is quite unlikely to happen.

Statistically, dam failure of a dam of your local type (massive concrete gravity) is quite rare, is generally slow to actually happen, giving several hours warning, and perhaps if it does fail, by that time you may well be sitting far away, in a rocking chair perhaps even holding your own grandchild in your arms, or Posting Topics and Replies at

There have been massive concrete gravity dams which have failed due to their construction, but upon careful analysis, these were found to be defective materials, generally poor cement or aggregate, or improperly cured before having the reservoir filled behind the dam, or sited over a previously unknown geological fault, but Dworshak dam is owned by the US Army, and was constructed by the US Army Corps of Engineers, back in 1966 through 1973, and their expertise was at that time extremely good.

Dams have in the past been breached by a falling landslip into the reservoir which breached the dam with the shock-wave from the falling mass of earth, rocks and debris.

Geologically, the land above the Dworshak reservoir does appear to be reasonably stable, thus statistically there is not likely to have a major landslip occur into the reservoir.

Read more about your local Dam here:

http://en.wikipedia.org/wiki/Dworshak_Dam

http://www.cbr.washington.edu/crisp/hydro/dwr.html

Rpad and other maps refer: http://maps.google.com/maps?hl=en&client=firefox-a&channel=s&rls=org.mozilla:en-GB:official&resnum=0&q=orofino+ID+road+map&um=1&ie=UTF-8&sa=X&oi=geocode_result&resnum=1&ct=image

Since reading your Topic I have done considerable research on your local situation, far more than the few above weblinks, and I would thus presently "sleep easy" if I lived in Orofino.

I have had considerable experience in large Construction Projects, Hydro Stations of various types, and researched disasters, both man-caused and natural - Please read my Member Profile for further information.

If you wish, become a Member at by registering, it is free, and if you do, and wish to send me a PM (Private Message) through the facility offered to Members, I am always prepared to assist, to the best of my ability.

Any person who is able to research and think, can easily grow into an Engineer of remarkable ability.

So, Lily Ann, please stop worrying about the possible failure of the Dworshak Dam, because it is quite unlikely to happen while you live nearby.

From the above sea-level part of far away Supercontinent of Zealandia, most of which lies 2km below sea level.

I include my picture so you know who I am:

Kind Regards....

Lily Ann,
A bigger concern than dam failure is the possibility of a major water release by the Corp of Engineers due to excessive rain in the upper portions of the watershed or basin drained by the river. This happened in the Tulsa, Oklahoma area back in October 1986.

The Keystone Dam is about 16 - 17 miles west of Tulsa on the Arkansas River. In late September and early October, remnants of tropical storms moved over Northern Oklahoma and Kansas. These areas are drained by the Arkansas River. The storms dropped enough rain to fill Keystone Lake. The Corps was forced to release the water or risk the possibility of the water overflowing the dam. Areas of Sand Springs, Tulsa, and Bixby flooded, but the Corps worked with local authorities to issue evacuation orders in time for most people to get out.

Tulsa is fortunate in that it is the location of a district headquarters for the Corps, a National Weather Service Forecast office, and has a good stormwater management system. Co-located with the NWS office is a River Forecast Center that serves the Arkansas and Red River basins. The RFC is the agency that issues flood watches and warnings. The RFC staffers are hydrologists, scientists that study meteorology, geology and engineering, and they combine their knowledge of these areas to determine if the predicted amount of rainfall will or could cause a flood.

Sounds to me like you would make a good hydrologist.

You can go to www.weather.gov to locate the RFC that serves your area.

I am glad to see a young person take an interest in public safety.