If you look around at all the snow on the ground you might think those piles and piles of snow mean an end to the much-touted drought Maine has been in for the last couple of years. You might think that, but it’s not necessarily so, according to Greg Stewart, Data Section Chief of the United States Geological Survey (USGS). The USGS keeps a close eye on the snow. In fact, this week they’re sending teams out to look at how much snow there is on the ground. They really don’t care about just how high the snow is; rather what they really care about is how much water that represents.
Over the entire day, Caldwell will travel to six sites in Southern Maine and New Hampshire to check on the snow. After the rain the prior day the snow will be significantly denser than it would have been, but still not "ripe," ready to release its moisture. Other measurements will be taken all over the state over the next couple of days by USGS, The Maine Geological service, the Weather Service, paper companies, power utilities and other groups. When all the measurements are collected, all the parties will gather in Augusta for a conference to assess the situation. The information will be used to assess the danger of flooding and make preditions about water levels. The information will also be posted at the USGS website at: http://me.water.usgs.gov/
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Monday,
March 3 -Jim Caldwell of the USGS pulls a long aluminum tube
out of the back of his government van. Caldwell decides
against snowshoes for this trip and heads into a hardwood stand
near the
golf course in Auburn. Caldwell plunges the tube directly into
the snow, twisting carefully so the serrated edge can cut through
any ice layers, pulls out the tube, and weighs the snow that
it contains. Caldwell will repeat the process a dozen times here
and there to try and get a good average of how much water
equivalent
the
two
feet
of snow
represents at this site. 
By the end of next week, the USGS should have a good picture of how much water is sitting on the ground and just how close it is to melting. Lighter snowbanks can just absorb falling rain, but "ripe" snowbanks will melt right away.
Light fluffy new-fallen snow might have a water to air ratio of just .08 to 1, meaning that it’s mostly air. In this case, one foot of snow represents only an inch of water. When the ratio is upwards of .36 to 1 or .38 to 1, Stewart says it’s "ripe" and could melt right away; where one foot of snowbank contains approximately 4 inches of water.
What does that have to do with drought? Stewart says, "Drought means different things to different people." If you’re a farmer, you might want regular rain to soak the surface of your fields throughout the growing season. If you’re a hydroelectric producer, you want rain to fill your reservoirs with run-off so you can produce electricity. If you’re a water utility, you want ample groundwater to keep your wells wet and producing, and that has been the problem for some areas of Maine.
So all this snow means plenty of ground water for water utilities and wells? Not exactly, says Stewart, it depends on this spring’s weather. In order for ground water to replenish, or "recharge" as Stewart puts it, the ground needs to be saturated and able to transport water -- as it's generally able to do during spring and fall months.
In the summer, vegetation absorbs almost all of the water falling on the ground, so little of it makes it deeper into the ground. In the winter, the ground is frozen and can’t transport water, so it sits on the surface. In the fall, after the plants die back, but before frost penetrates the ground, water flows freely and recharges the aquifer. In the spring, after the ground thaws and before the plants start drinking it up, water is again replenished. Right now in Southern Maine, ground water is on the low side of the normal range. In Northern Maine, things are still pretty bad because there was little rain in the fall.
The snow on the ground means potential improvement, but only if the weather cooperates. Should we get a significant warm rain before the ground has the opportunity to thaw, most of the water in the snow will wash away into streams and rivers and out to sea, possibly creating floods along the way. The best situation occurs if no significant warm rain falls before the snow melts.
So while all this snow could alleviate the drought, given the wrong weather, we could actually have a drought despite the snow and flooding because of it. Should we avoid a big warm rain event until after most of the snow has naturally melted and the ground has thawed, we’ll get drought relief without flooding.
by Chad Gilley
March 3, 2003
Contact: gilleymedia@live.com
