vision2020
Re: groundwater declining
My understanding as a student of local geology is that the aquifer being
currently used by the city is the very deep Grande Ronde, and that it is likely
"fenced in" by the intrusive granite formation that makes up the Palouse Range,
and by the deep metamorphic formations that are Tomer Butte, Paradise Ridge and
the ridge line to the south of town. This esentially leaves the Paradise Creek
drainage and perhaps parts of the South Fork of the Palouse River drainage to
regharge the aquifer. This is not a very large area, and as we have found out
from dropping levels, the recharge rate seems to be slower than our rate of
use. I think Will is right when he says that year to year variations in
precipitation do not affect the Grande Ronde Aquifer. However, an increase or
decrease of precip over many years probably would have a measurable effect.
Another thing to keep in mind is that the shallower the aquifer, the more likely
it is that contamination can occur. I currently live on property just outside
of town where the older (and shallower) of two wells cannot be used due to
chemical contamination.
This brings up something that has been nagging me for quite a while. Some
municipalities and irrigation districts have started aquifer recharge projects
where extra or already used water is actually pumped down into the substrata.
This technique has been successful at least in some cases where the aquifers in
question showed increases in their levels. When I learned of this my first
thought was toward Moscow's wastewater that leaves our sewage treatment plant
into Paradise Creek. I asked a couple of faculty members in the Geology
Department why we couldn't simply pump that water back uphill a ways, then push
it back into the ground. The answer was, to their knowledge, that the only
reason this is not done in more places is public perception. That is; many
people might have an aesthetic problem with the idea of used water being put
into an aquifer, and as we all know, public perception can do almost anything.
In reality, water moving down into and through a basalt aquifer is very
thouroughly cleaned and is perfectly safe for consumption. After all, some of
our street runoff and treated wastewater ends up in the aquifers below already.
Again, the more rock the water has to travel through, the cleaner the water.
This idea got me thinking even more when I learned that we were spending
money to lower the temperature of the water that goes into Paradise Creek to
comply with EPA regulations. Those are improvements that wouldn't have to be
made if the water was going back into the ground.
Anyway, these are just ideas, and I'm certainly not an expert. But I do
wonder if anyone with the city has looked at mechanized recharge as a
possibility. It is my understanding that it is very difficult to predict how
long we have before aquifer levels become a problem, especially with population
growth in the area and increasing business activity. If we don't come up with a
solution for our own aquifer, eventually we will be faced with the need for
water to be piped from the Potlatch area, or from another municipality that has
not used their water up yet. The question that arises is: do we want to absorb
some of the cost of this problem now, or do we want a later generation to have
to pay for all of it?
-Fred
Will Simpson wrote:
> Shahab, I think you are a little off the mark in your thinking that private
> out of town wells draw from the same groundwater source that the city does.
> For the most part they don't! It is more likely that our city friends will
> run out of water before your county cousins do. The groundwater source the
> city draws from (Grande Ronde Basalt aquifer) is very deep and the
> mechanisms by which this deep aquifer is recharged are largely unknown. The
> groundwater sources tapped by "private" wells are very shallow and these
> wells are recharged by the local annual rain fall. These shallow ground
> water sources do not drain vertically but drain horizontally towards the
> Columbia Basin and ultimately to the ocean. My understanding of the deep
> aquifer tapped by Moscow/Pullman is that it is unaffected by variations in
> the local rain fall. These are two different water sources and they do not
> appear to be connected. Maybe someone on the list with more technical
> knowledge about the recharging mechanisms of they area's groundwater sources
> could add to this discussion.
>
> The disturbing trend is with those deeper wells. There may still be pockets
> of problems in the county and those problems would be the result of local
> dwelling density and usage or local geological situations where shallow
> ground water can't be retained as in the South flank of Moscow Mountain.
> Ground water in my area of the county is artesian or almost artesian and
> wells are very shallow - less than 100 feet.
>
> All this being said, we are still face a problem in our community which will
> greatly effect us who live in the county. Along with conservation we are
> likely going to have to help, financially, the cities find alternate sources
> of water. Here is where us country folk can help. One option for an
> alternate source of water would be a surface reservoir. This would capture
> more of the seasonal ground water, have a relatively short pumping distance
> and relieve pressure on the deep aquifer. Another option I've heard is to
> pump water up from the Columbia.
>
> Below is a quote that might interest you from
> http://www.uidaho.edu/pbac/okproject.html the site hosted by Palouse Basin
> Aquifer Committee that further explains the problem with the Grande Ronde
> Basalt aquifer.
>
> "The research (PBAC Funds Major Research Project ) will be conducted by Drs.
> Kent Keller of WSU and Jim Osiensky of the UI. Both professors will utilize
> some of the funding for graduate student projects. The Palouse Basin relies
> entirely on groundwater to meet all of its water supply needs. There are two
> major aquifers within the basalt that are being tapped by water wells: wells
> shallower than 250 feet are generally in the Wanapum Basalt which generally
> yields less than 1,500 gallons per minute (gpm); deeper wells in the Grande
> Ronde Basalt aquifer are capable of yielding upwards of 3,000 gpm.
>
> Previous studies have indicated that annual pumping withdrawals in the
> Palouse Basin by the four major entities is substantially less than rates of
> flow through the basin (for example, in the form of precipitation). However,
> groundwater level data collected in the pumping centers of Pullman, Moscow,
> and Palouse indicate that water levels in the Grande Ronde aquifer are
> declining at a rate of 1.5 feet per year, in continuation of a 100-year
> trend. "
>
> Will Simpson
> Kestrel Creek Gallery
> Exploring the Potential of Wood Turned Art
> http://www.kestrelcreek.com
>
> ----- Original Message -----
> From: Shahab Mesbah <meteor2@moscow.com>
> To: Greg Brown <gregb@alaskapacific.edu>; <vision2020@moscow.com>
> Sent: Thursday, February 08, 2001 4:35 PM
> Subject: RE: groundwater declining
>
> > Dear Greg,
> >
> > I agree with almost all of what you say! The fact is that the wells in the
> > area are dropping fast. The city well will not run out soon but the
> private
> > (out of town) wells are far shallower and will be running out soon indeed.
> >
> > As you mention Moscow has not done well to conserve the problem is mainly
> > our culture. Lets face it... there are individuals that conserve in this
> > country but we, as a population, are very much into consuming everything.
> We
> > cause all kinds of damage to our environment because we refuse to
> > acknowledge the fact that our consumption level is not sustainable. We
> > continue to consume the majority of the resources in our world yet we are
> > but a fraction of the population.
> >
> > Your brother in arms,
> >
> > Shahab...
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