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> > * I had the same thought about vernal pools at the CARCNET me Wow! Those slacks are way bigger than I thought they were. Nancy On 2014-05-23, at 3:14 PM, Randy Lauff <randy.lauff@gmail.com> wrote: > 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. > > > &g