a) From the Catskills
to Canal Street: New York City's Water Supply, by Schneiderman,
in The Earth Around Us.
b) The Edwards
Aquifer: water for thirsty Texans, by Sharp and Banner, in The
Earth Around Us.
Report on irrigation canals in Nebraska and the role they play
in water management and the environmental concerns associated
with them. You should definitely do some research for this topic
(unless you happen to have extensive personal experience with
this topic). The web is one source of information. List your sources
at the end.
The hydrologic cycle and sources of water in general.
- surface resources - rivers, lakes, reservoirs.
Drought and quality concerns. It can cost twice as much to treat
surface water to meet drinking quality standards as it does groundwater.
- groundwater resources - variety of aquifers.
Generally higher quality water, but depletion concerns exist.
Greatly increasing dependence on in the U.S.. Science of hydrogeology.
- Are surface and groundwater resources separate?
- collection of rainwater.
- towing of icebergs.
Multiple uses of water and the debate on Missouri River
What are the myriad of uses water is put to?
- drinking (for us, our pets, and our livestock).
- irrigation (from crops to lawns).
- power generation.
- cleaning (from streets to laundry to coal).
- sewage removal and disposal.
- industrial cooling.
- recreation: boating, swimming.
- fire protection.
- ecosystem maintenance.
- aesthetics (fountains and such).
- note that some of the uses may be in conflict
with each other, or that in a given area there is not enough
water to go around.
Who are Missouri River management 'stockholders':
- power generators on upstream dams.
- commercial barge traffic.
- recreational boaters.
- industry (cooling water intake).
- power generation.
- farmers and flood control.
- recreational users of reservoirs.
- those who wish wildlife and habitat maintenance.
The concept of riparian corridor is important here.
- distinctly competing interests. What do each
of these 'want' from the river and when?
Missouri River management history:
- no management early on, adapt to and/or accept
consequences of associated unpredictable and dynamic river behavior
- e.g. Carter Lake, and the steamer Bertrand at De Soto
- 1950s and 1960s - extensive engineering;
including building of dams, closure of minor channels, cutting
off of some bends (e.g. De Soto Bends), and stabilization of
banks and installation of jetties. Extensive levee systems were
installed along sections of the river. This was amazingly successful
overall. Some have referred to the result as the big ditch.
- debate now is on how to reestablish habitat
for endangered species. Two basic approaches in the back to the
- reconnect some chutes (e.g. Boyer Chute)
to provide shallow water and sand bars.
- modify flow patterns by controlling dam releases
in order to mimic a scouring spring flood.
- the debate on Missouri River management has
become heavily politicized.
Sources of water for Omaha.
Florence Plant, North Omaha, processing of Missouri River water.
Platte River well field, not to far from Offutt.
What does a water well typically consist of
- components: casing, screening, gravel
pack, bentonite seal, grouting, surface cover.
- what is rationale for these different components?
Pumping behavior of a well:
- draw down cone
- factors that determine geometry of?
- pump test, yield and transmissivity.
- composite cones, and well fields.
- importance of recharge rate.
The source of water for the Platte River well
MUD document on third plant.
Dr. Schimmrich has collected links to hydrology
The High Plains Aquifer.
The extent of the
aquifer is shown in this map from a USGS site. The following quote
gives you some idea of its importance. "Approximately 20
percent of the irrigated land in the United States is in the High
Plains and about 30 percent of the ground water used for irrigation
in the U.S. is pumped from the High Plains aquifer. Irrigation
withdrawals in 1990 were greater than 14 billion gallons per day.
In 1990, 2.2 million people were supplied by ground water from
the High Plains aquifer with total public-supply withdrawals of
332 million gallons per day. " http://webserver.cr.usgs.gov/nawqa/hpgw/HPGW_home.html
Geology of the aquifer:
In words - a large wedge of silts, sands and
gravels that were shed off the Rocky Mountains to the West. Three
major units are typically recognized. It is the youngest one,
the Ogallala Group, that is a key geologic unit that often lends
its name to the aquifer. USGS map below shows the distribution
of some of the related units.
View of water seeping out of the High
Plains Aquifer on the south side of the Niobrara River valley
just down stream from Valentine.
Sand Hills of Nebraska:
- consists of a large, stabilized (by grasses)
- has dune sand with a porosity such that it:
- doesn't allow runoff and associated drainage
network to develop.
- provides for great recharge and hence a shallow
groundwater table. In places the groundwater table emerges at
interdune depressions as lakes, wetlands and subirrigated meadows.
These are very important habitats (including pelicans).
- is difficult to impossible to grow crops
on (so ranching is the major land use).
- nourishes several narrow rivers (Loup, Snake,
and Dismal) with semi-constant leakage out of the aquifer.
Changes in the aquifer
water table with time. This is a USGS
figure from the report cited below in the related links. It shows
areas of intensive agricultural withdrawal. Why the increases
in certain parts of Nebraska.
Water quality characteristics of the High Plains
- varies considerably due to local factors.
In Nebraska it is mainly high-quality water.
- with the intensive agricultural activity
and related feedlots sitting right on top of the aquifer, agrichemical
contamination is a real concern.
Interstate commerce in water?
USGS photo of center pivot irrigation
fed by the High Plains aquifer near Elkhart Kansas. So much that
is important is hidden from view!
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