A26-Lancaster Farming, Saturday, March 23,2002
Penn State Cooperative Extension
Capitol Region Dairy Team
DO YOU HAVE ENOUGH
WATER FOR THE
SUMMER?
Thomas R. McCarty
Extension Agent
Water Quality
Capitol Region
Holes in rock are selling like
funnel cakes at the county fair.
The folks who make them are ex
tremely busy in southeastern
Pennsylvania. The folks buying
them usually already own one
that is proving to be too shallow.
I am talking about wells, of
course.
The water table is reaching re
cord low levels in many places.
When it drops below the bottom
of a homeowner’s well, it causes
them an inconvenience. When it
drops below the bottom of your
farm well, it’s an emergency!
The point is, there are only few
people depending on the water
from a homeowner’s well while
there are probably SO to several
hundred cows drawing water
from your farm well Households
can be supplied with water from
the grocery store, but your farm
cannot.
I hope this convinces you to do
two things. The first is to make a
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plan for a water emergency. The
second is to monitor the water
level in your welL This will allow
you to predict a water shortage
far enough ahead to be able to
supply water without interrup
tion.
Let’s look at monitoring your
well first I mentioned that
groundwater levels are reaching
record lows. This year’s window
of opportunity for recharge is
also closing. Recharge usually oc
curs between October and May.
After crops begin growing active
ly, they effectively prevent rain
fall from reaching the water
table. They transpire water at
rates sufficient to use all rainfall
that infiltrates from May to Sep
tember.
For this reason, I believe moni
toring of wells supplying live
stock water is an important first
step. We will enter the summer at
record low levels and the levels
will likely fall still farther. We are
entering uncharted territory.
The object of monitoring is to
determine if there is adequate
water over the pump intake in
the well for uninterrupted water
use. I suggest two measurements
be made on the same day. The
first should be done at the end of
a period of minimum use, per
haps the first thing in the morn
ing. Suppose you measured 50
feet from ground level to water
level. The second measurement
should occur at the end of a peri
od of maximum use. This would
typically be after the morning or
evening chores are finished. Sup
pose this measurement is 150 feet
from ground level to water level.
Repeat these measurements fin
several days to be sure they are
representative. If there is little or
no difference between these two
measurements, the well is high
yielding. Significant differences
in these two readings is an indi
cation that the flow rate of the
well is beginning to diminish.
To evaluate die measurements
we also need to know at what
depth the pump intake is located.
Let’s suppose it is at the 200-foot
level. A morning measurement of
SO feet would indicate there is
150 feet of water over the pump.
This should make you cheer. A
measurement of ISO feet follow
ing a heavy use period still leaves
us with SO of water covering die
pump. This is still adequate,
since 10 feet of water should be
sufficient to let the pump operate
satisfactorily. The difference be
tween the two readings, which in
this example was 100 feet, should
be written down somewhere for
monitoring and for future refer
ence.
The next step is to continue the
early morning measurements on
a weekly or monthly basis. If this
measurement drops to 90 feet
and the differential reading stays
at 100 feet, the well has now
reached the critical point of 10
feet of water over the pump dur
ing heavy use. Monitoring the
water levels periodically and
graphing the readings over time
can help you predict when you
could potentially expect a serious
water shortage problem.
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Let me list some key points
about measuring water depths.
First, don’t drop equipment
down the well. Bore a hole in a
piece of plywood and feed the
measuring tape through that.
Second, don’t get the tape stuck.
There are centering guides along
the pipe to make the pipe and
wire stand off from the borehole,
which makes the job of lowering
the tape interesting. Connect a
slender weight securely to the
tape, and make sure there are no
edges or frays that will cause it to
get snagged. Don’t use a weight
that would be a catastrophe if
lost in the well, such as lead, for
example. A steel tape coated with
carpenter’s chalk makes the
water level easy to read. A solid
cake kind of chalk works well for
this. Finally, the tape and weight
should be disinfected before send
ing it down the borehole. If you
don’t have a bacteria problem,
don’t create one.
The other important action to
take is to develop an emergency
plan. What would you do if there
were no water tomorrow morn
ing? We hope you will never ex
perience this. How could you
quickly get water to the operation
in this emergency?
Some important things to con
sider are a source of water and a
way to get it to the farm, a sani
tary storage tank, a second pump
to remove water from storage,
piping to deliver water-to the ap
propriate places, and a method of
disinfecting the water. This plan
should be reviewed with other
people who will be affected, such
as the milk sanitarian, the con
tractor for feeder animals, em
ployees, etc.
Longer term planning could
include having a back up pump
and all the equipment necessary
for pulling the pump. Materials
to sanitize the well after pump re
placement should also be avail
able. A possible long-term goal
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could be to have a backup well,
especially on a larger operation.
Before drilling a well, consult
with a hydrogeologist to help se
lect a site that is likely to provide
a high yield of water. Is the site
far enough removed from other
wells and possible sources of con
tamination? Is it in a convenient
location for future expansion?
After satisfying these considera
tions, the well can be drilled and
developed. Developing a well re
fers to the procedure used to
clean mud from the walls of the
borehole and fines from the water
bearing zones near the well so
that the well can achieve a high
yield.
Be sure the well is properly
cased and protected from surface
water contamination. Final con
siderations would be providing
adequate pipe and wire size for
satisfactory pump operation.
Also, develop an effective main
tenance schedule for the well, es
pecially if it remains an occasion
al-use well.
Consult the following refer
ences for additional information;
• http://www.crh.noaa.gov/er/
marfc/ Mid-Atlantic River Fore
cast Center, a source for weather
data.
• http://waterdata.usgs.gov/
pa/nwis/current?type= gw USGS
site providing water levels in
their monitoring wells.
• http;//
www.dcnr.state.pa.us/topogeo/
Department of Conservation and
Natural Resources, which pro
vides information about ground
water and wells.
• http://www.cas.psu.edu
Penn State College of Agricultur
al Sciences site. Look under Cur
rent Issues Drought, for more
information.
• “Managing Your Well Dur
ing a Drought,” a fact sheet
available from Penn State Coop
erative Extension.