2001 Well Readings 2001 Agricultural Irrigation Use Data Raingage Readings 2001
2002 Well Readings 2002 Agricultural Irrigation Use Data Raingage Readings 2002
2003 Well Readings 2003 Agricultural Irrigation Use Data Raingage Readings 2003
2004 Well Readings 2004 Agricultural Irrigation Use Data Raingage Readings 2004
2005 Well Readings 2005 Agricultural Irrigation Use Data Raingage Readings 2005
2006 Well Readings 2006 Agricultural Irrigation Use Data Raingage Readings 2006
2007 Well Readings 2007 Agricultural Irrigation Use Data Raingage Readings 2007
2008 Well Readings 2007 Agricultural Irrigation Use Data Raingage Readings 2008
Data sheets, Forms and PDFs (Map, Strategy and Permitting Ordinance),
The Imperial Valley Water Authority was established in 1989 by referendum. It comprises
all of Mason County and four townships in Tazewell County. It operates under the Water Authorities Act
of 1951. The act gives the trustees various powers, one of which is 'To reasonably regulate the use
of water and during any period of actual or threatened shortage, to establish limits upon or
priorities as to the use of water.'
The year 2000 saw dramatic drops in the water levels in most of the 13 observation wells in
Mason and Tazell counties where rainfall was below average for the year. However, despite below
average rainfall in 2000, data collected by the Imperial Valley Water Authority suggest that
the number of gallons of water pumped for irrigation was down too, probably due to the timing
of the rainfall.
The long-term annual rainfall measured in the Imperial Valley Water Authority's Raingage
Network over the past seven years has been 35 to 37 inches. For the first 11 months of 2000
precipitation levels fell below that amount with an average of 27.60 inches among the 20 sites.
Interestingly, 8 to 12 inches of that amount came in the last ten days of June and the
first five days of July, representing nearly 40% of the year's total.
The Imperial Valley Water Authority also has a network of observation wells which have
been checked monthly since May 1995. These wells have shown a steady decline since the July-August
period of 1998. It appears the shortfall on precipitation translated into lower water levels.
Throughout most of 2000 the water in the wells was 2 to 3 1/2 feet lower than the same period
in 1999.
Not surprisingly, the only deviation was the June-July period, which was the only time
that rainfall was dramatically above average.
Using a formula based on power consumption a way has been determined to estimate the
amount of groundwater used by agricultural irrigation. For the irrigation season from June
to September it is estimated that 36.2 billion gallons were used in 2000 for irrigation. This
compares to 45.7 billion gallons in 1999, 35.9 billion gallons in 1998, and 45.3 billion
gallons in 1997.
Generally, July and August see the greatest average irrigation withdrawals. Although
2000 had below average rainfall, there was also below average irrigation use. What rainfall
there was came at the right time because only 60% of the total irrigation was used during
July-August, as compared to 70% in 1999, 74% in 1998 and 87% in 1997. Despit the shortfall
in rain, more water was pumped in five of the past six years than was pumped in 2000, even
though there are more systems in use today than ever before.
As we enter the new millennium, observers look at the historical data to seek out
expected trends for the future. Groundwater data going back to 1930 shows that in the first
part of each decade, the water table has been above the average depth below land surface,
and the last half of each decade has been below the average depth below land surface, with
the exception of the 1950s when the water levels remained below average form 1949 to 1961.
If the pattern holds, it could be expected that this coming year should begin a time
of average to above average rainfall for a few years.
(The Imperial Valley Water Authority board has contracted service with the Illinois
State Water Survey to set up and maintain a network of raingage and observation sites. It
is the strategy of the board to continue to gather information and work with the State
Water Survey to obtain analysis and understanding of the information gathered.)
2008 Meeting Dates
Trustees
Morris L. Bell Chairman 3278 CR 1030E Chandlerville IL 62627 Dorland W. Smith Secretary E-Mail dormsmit@fgi.net Wayne Deppert Treasurer E-Mail depperts@dpc.net Don Osborn Jr. Trustee Mark J McGrath Attorney FAX (309) 359-8918E-Mail McGrath_PC@hotmail.com Steve Wilson, w/ISWS Advisor E-Mail swilson@ses.uiuc.edu 2204 Griffith Dr Champaign IL 61820
The observation Wells are located at the various sites as indicated on the map. They are dedicated wells, used only for the purpose to monitor the water table. The wells are measured on the first day of each month, except January and February. During the high usage months of July and August, the wells are also measured on the fifeenth. The data for the Observation Wells will be updated monthly, exept January and February. The raingage Network Stations were designed, set up, and are maintained by the Illinois State Water Survey under contract with Imperial Valley Water Authority. Local obervers pervorm weekly raingage maintenance at 11 sites, while the other nine raingages are serviced monthly by a local person trained and paid by the Illinois State Water Survey. As needed, a Champaign-based scientist vists the network to perform maintenance and repairs. The map shows the locations of the sites, and the data table shows the amount of precipitation collected on a monthly basis. Also the monthly average compared to the previous year. The estimated gallons withdrawn by agricultural irrigation is shown, and is compared with several previous years. A formula was devised to determine the gallons used by irrigation. The results of this formula compares favorably with the study conducted by the Illinois State Water Survey in the years 1988 and 1989.
Other links
Army Corps of Engineers (Rockland District, Water Control Section)
Illinois State Geological Survey Home Page
Illinois State Water Survey Home Page
Illinois Water Resource Center
Mahomet Aquifer Consortium Home Page
USGS - Water Resources of IllinoisHosted by Infobahn Outfitters
as of April 2, 2007
www.myfreecounter.net
Last updated 5-2-2008
Created 4-30-1997 by Robb Roper