sailor:
I think you are misunderestimating the problem. The tidal range at the mouth of the Chesapeake Bay is not so big and it creates significant tides and currents on the Bay, like water sloshing along a shallow tray. What an 18 foot tide would do would be just huge . I cannot see how you could possibly just have a canal open to the ecean at both ends. No way.
Because you have a small opening into a large bay, once the water is “in” the bay its resistance to flow/get outa the way is greatly reduced.
Its sorta a reverse/converse/inverse? version of a waterfall.
A long narrow channel is a totally different hydrological beast. There is significant resistance to water flow the whole way.
The situations are quite different.
Now, if somebody with real hydrological knowledge comes along and says it bad, I’ll certainly believe them.
To reiterate, a sea-level canal in Nicaragua is not feasible. Since the bottom of Lake Nicaragua is some 15 feet above sea level, and the surface 100 feet above sea level, a sea-level canal would necessitate draining the lake, which would eliminate a major advantage of the route. In any case, the 18-foot tides apply to the Gulf of Panama specifically. Tides on the Pacific coast of Nicaragua are much smaller.
jayjay
April 24, 2009, 6:22pm
23
Colibri:
To reiterate, a sea-level canal in Nicaragua is not feasible. Since the bottom of Lake Nicaragua is some 15 feet above sea level, and the surface 100 feet above sea level, a sea-level canal would necessitate draining the lake, which would eliminate a major advantage of the route. In any case, the 18-foot tides apply to the Gulf of Panama specifically. Tides on the Pacific coast of Nicaragua are much smaller.
Ah…thank you. Got it now.
This article discusses the results of a 1947 study on the question.
A feature of a sea level Panama Canal which has aroused much dissension over the years is the control of tides which have a variation of as much as 20 feet between the pacific and Atlantic entrances. To solve this problem a mile-long test model was built near Miraflores and fitted with tide-making machines to duplicate in miniature the tidal effects. By extensive tests of this scale model and other hydraulic studies it was determined that currents up to a maximum of 4.5 knots would be generated in the channel during extreme tidal variations. This would shade to slack water twice daily because of the diurnal tides in the Pacific.
The 1947 report recognized that navigation through an uncontrolled sea level channel would be entirely feasible with currents up to 4.5 knots but recommendations were made for tidal regulating facilities as a safety factor and for the convenience of shipping.
A simple scheme providing wide latitude in operation was proposed. This was for a tidal lock, 200 by 1,500 feet, on the main channel with a movable tidal barrier or dam on a parallel and connecting navigable pass. Both the main channel and navigable pass could be kept open an average of 7.7 hours a day, operating on a schedule to permit currents in the Canal up to two knots.
So although the problems with tidal flow are not insurmountable, they are significant, and tidal locks would be recommended.
Thanks for the detail !
Thats about what I figured. Significant, but tolerable current, but certainly not surfs up dude! levels
Of course, one engineer’s problem is another’s opportunity. Those same tidal flows can be used to generate electrical power.
True. However, the present Panama Canal produces a substantial amount of hydro power by using water that is not needed for lockages in three electrical plants.