Sasanoa River's Hell's gates-local knowledge please

[gyork]

If one were CW circumnavigating Arrowsic/Georgetown Islands, how would she determine the optimum slack flood time to come through Upper, then Lower gates. Aside from watching/waiting the water, how more precisely to anticipate the right time to head downstream? If your response includes info. relative to high tide, please reference LOCATION.

Also, what sort of turbulance might one expect at the Hanson Bay/Kennebec junction?

Thank you.

Gary

[JohnHuth]

Attached is a set of screen shots. Top one is the tide information for Mill Point on the Sasanoa River - subordinate tide prediction.

The next one down is the current prediction for Lower Hell gate, and then the next one down is the current prediction for Upper Hell Gate. All are for May 13th and should be for the same time period.

For Lower Hell Gate, you can see that the max flood current is maybe just a shade later than the midpoint between low and high from the Mill Point station prediction. Ebb pretty much the same. So, if you just remember the mid-point of high-low for Mill Point station, that's probably close enough.

You can see that Upper Hell gate has a funkier current pattern with max flood occurring coincident with high tide at that station - very peaky. Ebb on the other hand is of longer duration (also lower speed) but coincident with low tide at the Mill Point station.

Lower Hell Gate has higher currents, clearly.

On the Kennebec/Hanson interface, I've only been there on the ebb, but there was a fair amount of turbulence in the little embayment to the point to the south side of the bridge on the Kennebec side of the bridge. On the Hanson Bay side, not so much. I attribute the turbulence to the water getting diverted between the Sasanoa and the Kennebec, so having it downstream makes sense.

I'd imagine that the turbulent region would shift more to the north on an incoming tide and probably wouldn't be as bad as on the ebb. I have an e-mail out to my buddy who has paddled this a gazillion times, so he probably knows better for other conditions.

The turbulence wasn't too-too bad that it couldn't be managed, but it's a bit funky where it pops up - not the easiest to predict.

[gyork]

Thanks John for the resources. I think if I am at Mill point at predicted HT, I will be in good shape, after having "struggled" against the 1k surge through Upper, a few minutes before!

gary

[PeterB]

Gary, here are the 2014 current tables for Upper Hell Gate and and Lower Hell Gate

Upper Hell Gate , Sasanoa River

http://tidesandcurrents.noaa.gov/get_predc.shtml?year=2014&stn=5595+Portsmouth%20Harbor%20Entrance&secstn=Lower+Hell+Gate,+Knubble+Bay&sbfh=%2D0&sbfm=13&fldh=%2B0&fldm=46&sbeh=%2D0&sbem=54&ebbh=%2B0&ebbm=04&fldr=2.6&ebbr=2.3&fldavgd=290&ebbavgd=155&footnote=ac2

Lower Hell Gate

http://tidesandcurrents.noaa.gov/get_predc.shtml?year=2014&stn=5595+Portsmouth%20Harbor%20Entrance&secstn=Lower+Hell+Gate,+Knubble+Bay&sbfh=%2D0&sbfm=13&fldh=%2B0&fldm=46&sbeh=%2D0&sbem=54&ebbh=%2B0&ebbm=04&fldr=2.6&ebbr=2.3&fldavgd=290&ebbavgd=155&footnote=ac2

[Cath]

Gary - I have launched from the George Wright launch just after high tide in Bath and had no trouble at upper hell's gate. We also had plenty of time to get out through Goose Rock after a swimming break, then ate at Five Islands and returned through Goose Rock to Robinhood. Last year I also put in at the same place at high tide in Bath, and went around Arrowsic, There were some some strong eddy lines at upper hell's gate and a short bit of current to push through, but it was not too difficult. After going down the Back River and returning by the Kennebec, we entered back into the Sasanoa to take out at George Wright. We had no trouble with that. It is a fun trip.

I have been stranded all night at the airport and have nothing with me to refer to, to give any better details yet. I do love the Sasanoa, and would go down with you any time.

Cath

[gyork]

Thanks for all your helpful input, friends. Have added the "currents" link to my favorites list. Interesting/important info to have on hand, especially when navigating Maine's coastal rivers. As an example, on day X, at Fort Popham (Kennebec), it takes 2 hours beyond listed LT for the weak(er) early flood to overcome (slack) the natural flow of the mighty Kennebec. For the Damariscotta, the delay is ~ 1.5 hours. All good stuff to know, as most of us prefer to paddle "downhill"!

gary

[NateHanson]

Thanks for all your helpful input, friends. Have added the "currents" link to my favorites list. Interesting/important info to have on hand, especially when navigating Maine's coastal rivers. As an example, on day X, at Fort Popham (Kennebec), it takes 2 hours beyond listed LT for the weak(er) early flood to overcome (slack) the natural flow of the mighty Kennebec. For the Damariscotta, the delay is ~ 1.5 hours. All good stuff to know, as most of us prefer to paddle "downhill"!

gary

You'll find that this delay of slack current vs. high tide, is not just caused by river current competing with the tidal current - it occurs in large part because all that tidal water that's been pushed up into inlets can't drain back out as fast as the tidal level at the Fort is dropping. This effect is quite noticable even in purely tidal embayments (where there is no fresh water river contributing to the flow), merely because the water can't flow in or out through a constriction, as fast as the tide goes up or down outside of that constriction. The effect is most obvious at someplace like Blue Hill Falls (where the Salt Pond takes almost 2 extra hours to continue filling after local high water passes).