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Index of Subjects This is a multi-part message in MIME format. ------=_NextPart_000_1ED8_01CF7458.C8B0AE80 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable 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.=20 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.=20 Have you been there in winter and if so does any of this register ? Yt, Dave Webster, Kentville=20 ----- Original Message -----=20 From: Randy Lauff=20 To: NatureNS=20 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 meeting = at Quebec City in 1999, during a presentation on Marbled Salamanders, = which come down into the vernal pools to lay their eggs on the dry = pondbed in the fall, and stay with them all winter. It turns out that = the vernal pools fill from the water table, as one would think sandy = dunes would. And yes, I've been monitoring water level in our local Wood = Frog ponds, fall and late winter, ever since then. fred. ------------------------------------------------------------ Frederick W. Schueler & Aleta Karstad Daily Paintings - http://karstaddailypaintings.blogspot.com/ Vulnerable Watersheds - http://vulnerablewaters.blogspot.ca/ study our books - http://pinicola.ca/books/index.htm RR#2 Bishops Mills, Ontario, Canada K0G 1T0 on the Smiths Falls Limestone Plain 44* 52'N 75* 42'W (613)258-3107 <bckcdb at istar.ca> http://pinicola.ca/ ------------------------------------------------------------ No virus found in this message. Checked by AVG - www.avg.com Version: 2014.0.4577 / Virus Database: 3950/7502 - Release Date: = 05/15/14 ------=_NextPart_000_1ED8_01CF7458.C8B0AE80 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable =EF=BB=BF<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META content=3D"text/html; charset=3Dutf-8" http-equiv=3DContent-Type> <META name=3DGENERATOR content=3D"MSHTML 8.00.6001.23588"> <STYLE></STYLE> </HEAD> <BODY bgColor=3D#ffffff> <DIV>Hi Randy & All, = =20 = May=20 20, 2014</DIV> <DIV> I don't have a clear picture of the topography, = either=20 dune or inland, but one possible source of water in the slacks is = drifting of=20 snow into pools.</DIV> <DIV> </DIV> <DIV> In woods south of Kentville, where I used to = walk in=20 winter, pools in woodland cradlehollows of swampy sites never froze. = With 2'-3'=20 of snow on the ground, the air cone was typically about ~1' across at = snow level=20 and 4" across at water level. Even at -20o C, with heavy=20 snowfall, 60 mph winds and drifting snow there would be no = hint of=20 ice. From the viewpoint of ppt per unit area these cones act as black = holes;=20 snow blows into them but, soon being water, can not escape.=20 These air cones were absent when snow was not deep enough to = act as a=20 good insulator. With sufficient snow cover drifted ~level over the = swamp,=20 the soil at the base of cradlehollows would warm sufficiently by = ground=20 heat from below to melt overlying snow and eventually generate one of = these air=20 cones.</DIV> <DIV> </DIV> <DIV> If these pools were sufficiently above the water = table=20 then they would tend to be transient but, in most soils (given = sufficient iron=20 and decomposable organic matter), infiltration rate at constant = head will=20 gradually slow d