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> Daily Paintings -http://karstadd --089e0149ced62a263f04fa15356c Content-Type: text/plain; charset=UTF-8 I have posted a picture of the slack here: http://people.stfx.ca/rlauff/307/PomquetSlack.jpg. One person I asked locally thought that the slack filled up again with the autumn rains. That's probably right, but I still can't discount snow melt accompanied by spring rain. I guess I'll find out this year. Randy _________________________________ RF Lauff Way in the boonies of Antigonish County, NS. On 21 May 2014 18:08, nancy dowd <nancypdowd@gmail.com> wrote: > Maybe it is just evaporation. Water accumulates in the leaf-lined slacks > in the Spring (rain and melt) and eventually warming temps and strong sun > evaporate it until it is empty. Over the summer heat and sun manage to keep > up with the rainfall not allowing it to accumulate for any length of time > (it must be hot down in those slacks). Then once the cooler temps and less > intense sun of Fall take over rainwater can accumulate once again in the > slacks until it freezes. > > Just a guess. > > Nancy > On 2014-05-21, at 4:39 PM, David & Alison Webster <dwebster@glinx.com> > wrote: > > > Hi Randy & All, > > I had imagined these dunes to be bare sand. With tree cover on the > peaks and presumably none on the slacks there is another effect that will > increase effective ppt in the slacks; sublimation on the tree canopy in > calm weather and selective snow accumulation in treeless areas (roads, > glades, etc) in windy weather due to less turbulence and less speed over > glades.. > > Yt, DW > > ----- Original Message ----- > > From: Randy Lauff > > To: NatureNS > > Sent: Wednesday, May 21, 2014 9:57 AM > > Subject: Re: [NatureNS] slacks - when do they refill? > > > > Thanks folks, > > > > I haven't been there in winter, despite my being in NS now for over 20 > years. > > > > Here's the landscape picture though. Picture an accordion, partly open > lying on its back. The bellows represent the dune system at Pomquet, there > are peaks and troughs (slacks), and precious little other elevations going > on. At the slack in question, the surrounding peaks of the dunes are > dominated by white pine and oak, with other trees as well. > > > > Fred asked, if the dunes are sandy, how are they holding water in the > first place? Basically, I think there is leaf litter which may be > accumulating in the slack to slow the water seepage. Further to Anne's > email, the slack in question is well back from the salt water, I suspect > there is no salt to speak of in that water. Mosquitoes are there in the > billions, peepers are deafening, both suggesting fresh water (though I > realize a few mosquitoes can tolerate brackish water). > > > > Randy > > > > _________________________________ > > RF Lauff > > Way in the boonies of > > Antigonish County, NS. > > > > > > On 20 May 2014 18:24, David & Alison Webster<dwebster@glinx.com> wrote: > > Hi Randy & All, May 20, 2014 > > I don't have a clear picture of the topography, either dune or > inland, but one possible source of water in the slacks is drifting of snow > into pools. > > > > In woods south of Kentville, where I used to walk in winter, pools > in woodland cradlehollows of swampy sites never froze. With 2'-3' of snow > on the ground, the air cone was typically about ~1' across at snow level > and 4" across at water level. Even at -20o C, with heavy snowfall, 60 mph > winds and drifting snow there would be no hint of ice. From the viewpoint > of ppt per unit area these cones act as black holes; snow blows into them > but, soon being water, can not escape. These air cones were absent when > snow was not deep enough to act as a good insulator. With sufficient snow > cover drifted ~level over the swamp, the soil at the base of cradlehollows > would warm sufficiently by ground heat from below to melt overlying snow > and eventually generate one of these air cones. > > > > If these pools were sufficiently above the water table then they > would tend to be transient but, in most soils (given sufficient iron and > decomposable organic matter), infiltration rate at constant head will > gradually slow due to formation of a local iron pan over decades or > centuries. This effect interested me because ortstein is sometimes very > scattered; patches 3-4' wide and 10-15' apart and these pools that collect > below air cones could account for this. Also prolonged wetting will slake > any soil aggregates and decrease infiltration rate. > > > > Getting back to dunes, in the idealized case of parallel linear > dunes and linear slacks and in deep snow conditions I would expect linear > narrow pools at the base of linear narrow trenches in the snow; V-shaped > deposits of ortstein if dunes are stable and not advancing. > > > > Have you been there in winter and if so does any of this register ? > > Yt, Dave Webster, Kentville > > ----- Original Message ----- > > From: Randy Lauff > > To: NatureNS > > Sent: Tuesday, May 20, 2014 4:20 PM > > Subject: Re: [NatureNS] slacks - when do they refill? > > > > Thanks Fred, but in a dune system, wouldn't that mean that the slacks > would be less than half full with water? These are sand dunes...very > porous, so I'm suspecting water leaching in from the hills of the dunes > into the slacks just couldn't fill them. This is unlike the condition in > vernal pools where there can be ample elevation around from which water > could leach in to the pool area. I'm thinking there has to be a significant > rain or snow fall to fill them. > > > > Randy > > > > _________________________________ > > RF Lauff > > Way in the boonies of > > Antigonish County, NS. > > > > > > On 20 May 2014 15:30, Fred Schueler <bckcdb@istar.ca>wrote: > > On 5/20/2014 2:18 PM, Randy Lauff wrote: > > > > Between several of the dunes at Pomquet Beach, Ant. Co., the slacks (the > > troughs between dune crests) fill with water, but by summer are dry. I > > guess I've just never been there at the right time to see when they fill > > again...it can't be just from winter melt water, since the slacks are > > almost full (and snow melts to about 10% its volume as water). Do the > > autumn rains fill them again, or the spring rains? Or is it a > > case-by-case scenario, which I'd just have to monitor? > > > > * I had the same thought about vernal pools at the CARCNET me