The water level in rivers
and streams is a good recorder of current weather events like a sudden
thunderstorm to long term drought conditions due to lack of precipitation.
A hydrograph [see right image], a graph that represents streamflow or
averaged flow rates over a period of time, may provide a visual clue
to the climate patterns around us. Explore the hydrograph
page in the Climate Science for 1 Year section.
Some inquiry questions to
ponder when viewing the hydrograph page are:
do you find in all of the hydrographs represented?
climate and seasonal patterns are represented by the streamflow patterns?
When a geographical location
has a means to record levels of precipitation and evapotranspiration,
one can devise a "budget" to determine water surpluses
or deficits on a monthly and annual basis. CTL offers a water
budget study in the Boulder Watershed in Colorado, USA. The Water
Budget Page compares two areas separated by 25 miles and differing
by almost 5,000 feet in elevation. Inquiry exercises make use
of water budget graphs and tables to assess when water shortfalls
The hydrographs on
the Comparing Different Decades page
show streamflow data from five different decades beginning with
This longer time-frame of water data offers an opportunity to
examine "outside" influences such as ENSO that periodically
inflicts drought conditions on large geographical regions. For
more about ENSO, view the Climate Science
for 10 Years and Climate Resource
for 10 Years pages.
Climate Summary pages to find out about significant drought events
or periods. In particular, viewsummary pages from the 10,
100, 1000 and 10,000
year sections. For inquiry purposes, when did these droughts occur
and what impact did they have on human civilization?
Climate History for 100 Years has a special section on drought.
Here, you will find a reconstruction of precipitation of Northwest
New Mexico that compares more recent drought periods to ones occuring
over the past 2,000 years. Additionally, visit NOAA's Paleo
Perspective: North American Drought page for more information
about how paleoclimatic data gives clues to dry periods of the past
and why we should care about droughts.
History for 1000 Years has a special focus on the Climate and
Culture of the American Southwest. The main question addressed in
this section is whether extended drought was really severe enough
to force the cliff dwellers [the Anasazi, the Ancient Ones] away
from the region? You will find an interesting discussion pertaining
to the question of drought and how it can impact human culture.
Lastly, you can scan the Climate
History Timeline for all drought events and periods.