ILLINOIS WATER AND CLIMATE SUMMARY

Transcription

1 ILLINOIS WATER AND CLIMATE SUMMARY April 2009 Illinois State Water Survey 2204 Griffith Drive, Champaign, IL Tel (217) Fax (217) April 2009 Overview (Bob Scott) Temperatures in Illinois during April were below average and precipitation was above average. Soil moisture within the top 40 inches of soil was above the long-term statewide average. Mean streamflows were above median values. Shallow groundwater levels were above long-term average depths. Temperatures across Illinois (Figure 1) for April were below average (a -0.9-degree departure). Crop Reporting District (CRD) temperatures ranged from 0.2 F above average (southeast) to 1.7 F below average (west). Precipitation amounts for Illinois in April were above average (Figure 1). The statewide average of 6.26 inches represented a 2.46-inch surplus or 165 percent of average for the month. The northwest CRD received the least amount of rainfall, 4.99 inches (141 percent of average), while the east-southeast CRD recorded the greatest rainfall total with 7.82 inches (197 percent of average). Based on preliminary data, this was the 5 th wettest April, 6 th wettest February April (three months), 15 th wettest November April (six months), and wettest May April (12 months) since Soil moisture conditions in the 0- to 40-inch (0- to 100-centimeter) layer in Illinois at the end of April were generally near normal to above normal near the surface, and slightly below normal to well above normal in deeper layers. Overall, soil moisture in Illinois at the end of April was above normal (Figure 1). Mean provisional streamflow statewide was above the median flow in April, 220 percent of median (Figure 1). Rivers throughout Illinois recorded monthly mean discharges ranging from normal to much above normal. The Illinois River and the Mississippi River exceeded local flood stages at some locations in April. Water surface levels at the end of April were below the normal pool/target operating level at five of 34 reporting reservoirs. At the end of April, Lake Shelbyville was 1.4 feet above its May 1 target operating level, Carlyle Lake was nearly at target operating level, and Rend Lake was 5.0 feet above spillway level. Lake Michigan s mean level remains below the long-term average. Statewide, shallow groundwater levels were above normal with an average departure of +2.5 feet. Combined with the change in normal monthly groundwater levels between March and April, a 0.8-foot increase in departures from last month was observed (Figure 1). Levels averaged 1.0 foot higher than March levels and were approximately 1.3 feet above April levels of last year. Figure 1. Statewide departures from normal Note: The WARM Network maps and extended network descriptions appear in the January and July issues. Water and Atmospheric Resources Monitoring Program Illinois State Water Survey Institute of Natural Resource Sustainability University of Illinois at Urbana-Champaign Contact Bob Scott: (217) , rwscott1@illinois.edu

2 Weather/Climate Information (Jim Angel and Bob Scott) Temperatures across Illinois for April were below normal (Figure 2 and Table 1). Kaskaskia (Randolph County) reported the warmest temperature in the state with a high of 89 F on April 26. Streamwood (Cook County) reported the coldest temperature in the state with a low of 22 F on April 4. Precipitation for April was above normal statewide (Figure 2 and Table 1). St. David (Fulton County) reported the highest one-day precipitation of 3.15 inches on April 28, and Newton (Jasper County) reported the highest monthly total of inches. Snowfall was observed in parts of northern Illinois. The heaviest snow was from an April 5 6 event that dropped 1 to 3 inches of snow between Peoria and Chicago. Peotone (Will County) reported the highest monthly snowfall total of 3.5 inches. Severe weather was infrequent in April with no reports of tornadoes and only scattered reports of hail on April 5 and 25. Hail sizes were 1 inch or less (a size in excess of which is required for the hail to be classified as severe ) and caused little damage. Illinois Climate Network (ICN) Data. Average daily wind speeds across Illinois for April (Figure 3) ranged from 5.9 mph at Dixon Springs to 13.7 mph at Bondville and Stelle. Stelle reported the highest wind gust for the month, 44 mph, on April 26. Strong winds existed elsewhere and on other days as well. Fairfield and Monmouth reported gusts in excess of 40 mph on April 10 and 21, respectively. The prevailing wind direction for the month was complex: northeasterly to northwesterly in northern Illinois to southeasterly in southeastern Illinois. Wind speeds in excess of 8 mph during the month varied from 183 hours at Dixon Springs to 572 hours at Stelle. (April has 720 hours.) Average air temperatures in April ranged from 47 F at DeKalb and Stelle to 57 F at Dixon Springs. Solar radiation totals in April continued a seasonal increase, ranging from about 462 Mega-Joules per meter squared (MJ/m 2 ) at Springfield, Peoria, and Orr to 540 MJ/m 2 at Dixon Springs. Potential evapotranspiration observations varied from 2.0 inches at Freeport, Peoria, and Stelle to 2.6 inches at Dixon Springs. Soil temperatures in Illinois during April ranged from 43 F at Big Bend to 56 F at Dixon Springs (4-inch level) and Figure 2. Illinois temperature and precipitation during April

3 Crop Reporting District Table 1. Illinois Precipitation (inches) and Temperature (ºF) by Crop Reporting District Apr 09 Amount Last Month Last 3 Months Last 6 Months Last 12 Months % Temp Feb 09- % Temp Nov 08- % Temp May 08- % Avg Dev Apr 09 Avg Dev Apr 09 Avg Dev Apr 09 Avg Northwest Northeast West Central East West-southwest East-southeast Southwest Southeast State Average Note: Data are provisional. Complete, quality-controlled data are available about six months after a given month. Temp Dev from 46 F in DeKalb and St. Charles to nearly 58 F at Dixon Springs (8-inch level). Extended climate outlooks issued by the U.S. Department of Commerce, National Oceanic and Atmospheric Administration, Climate Prediction Center for May and for May July call for equal chances of above, below, and normal temperatures and precipitation statewide. Soil Moisture Information (Bob Scott) Near-surface soil moisture values were above normal across most of Illinois at the end of April (Figure 1). In the 0- to 6-inch layer, values ranged from 99 percent of normal at Dixon Springs to 161 percent at Peoria. Conditions in the 6- to 20-inch layer were wetter, varying from 104 percent at Belleville to 165 percent at Olney. Moisture in the 20- to 40-inch layer showed some dryness in central Illinois, ranging from 70 percent at Peoria to near 175 percent at Olney. Conditions varied the most in the 40- to 72-inch layer, ranging from about 68 percent of normal at Freeport and Springfield to 178 percent at Brownstown. Overall, soil moisture in Illinois at the end of April was above normal (Figure 4). Compared to conditions at the end of March, soil moisture at the end of April in Illinois increased minutely (Table 2). Moisture in the 0- to 6-inch layer increased 10 percent at Champaign, but changes were 5 percent or less elsewhere. Changes in soil moisture in the 6- to 20-inch layer were small statewide: less than 4 percent. Similar conditions were observed in the 20- to 40-inch layer, except for an increase of 14 percent at Champaign and a decrease of 10 percent at Belleville. 3

4 Figure 3. April monthly averages and totals as collected by the Illinois Climate Network 4

5 Figure 4. May 1 observed percent-of-normal soil moisture based on mean 5

6 Location Table 2. Soil Moisture in Various Layers on May 1, 2009 May (inches) Change from Apr 1 (%) May (inches) Change from Apr 1 (%) May (inches) Change from Apr 1 (%) Freeport (NW) DeKalb (NE) Monmouth (W) East Peoria (C) Stelle (E) Champaign (E) Bondville (E) Perry (WSW) Springfield (WSW) Brownstown (ESE) Olney (ESE) Belleville (SW) Carbondale (SW) Ina (SE) Fairfield (SE) Dixon Springs (SE) Surface Water Information (Bill Saylor and Vern Knapp) River and stream discharge and stage data are obtained from gaging stations operated by the U.S. Geological Survey (USGS) or the U.S. Army Corps of Engineers (USACE). The USGS gaging station network is supported, in part, by the Illinois Department of Natural Resources Office of Water Resources, ISWS, and the USACE. Provisional discharge data are obtained from the USGS. Table 3 lists the provisional peak stage for the current month compared to flood stage at selected streamgaging stations located on the Illinois, Mississippi, and Ohio Rivers. The peak stage is determined from the daily morning readings posted by the National Weather Service (NWS) and/or the USACE. Water levels at most Illinois River gage locations below Ottawa (i.e., below the confluence of the Fox River) were above or near flood stage throughout April. The Mississippi River exceeded local flood stage at Grafton and at Chester multiple times during April. Provisional monthly mean flows for 26 streamgaging stations located throughout Illinois are shown in Table 4. Mean values posted by the USGS are listed if available; otherwise, daily mean discharge data posted by the USGS are used to estimate the mean flow for the month. Long-term mean flows for each month are published by the USGS. The month s median flow for each station listed in Table 4 was determined by ranking the April mean flow for each year of record, and selecting the middle value, 50 percent exceedence probability. The statewide percent of historical mean flow and percent of historical median flow are calculated by dividing the sum of the average flows this month at stations in Table 4 by the sum of the historical mean and median flows calculated for the month, respectively, at the same stations. This method is intended to weight individual observations proportionately in the aggregate comparison. (The Illinois River and Rock River stations are excluded from the statewide calculation because other rivers listed in Table 4 contribute to their flow.) Mean provisional flow statewide was above the median value for April (220 percent of the median) and above the long-term mean for the month (180 percent of the mean). Mean streamflow conditions throughout Illinois ranged from normal to much above normal in April. Water-Supply Lakes and Major Reservoirs. Table 5 lists reservoirs in Illinois, their normal pool or target water surface elevation, and other data related to observed variations in water surface elevations. Reservoir levels are obtained from a network of cooperating reservoir operators who are contacted each month by ISWS staff for 6

7 River Station River Illinois mile* Table 3. Peak Stages for Major Rivers during April 2009 Flood stage (feet)* Peak stage (feet)** Date Morris La Salle Peoria Havana Beardstown Hardin Mississippi Dubuque Keokuk Quincy Grafton St. Louis Chester Thebes Ohio Cairo Notes: * River mile and flood stage from River Stages in Illinois: Flood and Damage Data, Illinois Department of Natural Resources, Office of Water Resources, August 2004 (and Addendum, February 2007). ** Peak stage based on daily a.m. readings, not instantaneous peak. Stage data obtained from U.S. Army Corps of Engineers. the current water levels. Reservoir levels are reported in terms of their difference from normal pool (or target level). The average of the month-end readings for the period of record is reported in terms of the difference from normal pool or target level (column 6 of Table 5), and the number of years of record for each reservoir also is given (column 7). Most reservoirs serve as public water supplies, with the exceptions noted in the last column. Compared to end-of-march water levels at 34 reservoirs, end-of-april water levels were higher at 19 reservoirs, were the same as at the end of last month at 12 reservoirs, and were lower at three reservoirs. For the 34 reservoirs with observations reported at the end of April, water levels at five reservoirs were below normal pool (or target operating level), 22 reservoirs were above normal pool, and seven reservoirs were at normal pool or spillway level. (Note that some observers do not report height of water above spillway level when a lake has outflow, however.) Major Reservoirs. Compared to water levels at the end of March, Lake Shelbyville was 6.7 feet higher, Carlyle Lake level was 0.7 feet higher, and Rend Lake level was 2.8 feet higher. At the end of April, the water surface level at Rend Lake was 5.0 feet above spillway elevation, Lake Shelbyville was 1.4 feet above its May 1 target level, and Carlyle Lake water surface level was just below its May 1 target level. (Carlyle Lake and Lake Shelbyville target levels increased from April to May.) Great Lakes. Current month mean and end-of-month values are provisional and are relative to International Great Lakes Datum The April mean level for Lake Michigan was feet, compared to a mean level of feet in April The long-term average lake level for April is feet, based on data. Historically, the lowest mean level for Lake Michigan in April occurred in 1964 at feet, and the highest level occurred in 1986 at feet. The month-end level of Lake Michigan was feet. 7

8 Table 4. Provisional Mean Flows, April 2009 Drainage Years 2009 Long-term flows Percent Days of area of mean flow Mean* Median chance of data this Station (sq mi) record (cfs) (cfs) (cfs) Flow condition exceedence month Rock River at Rockton , above normal Rock River near Joslin ,720 10, above normal Pecatonica River at Freeport above normal Green River near Geneseo above normal Edwards River near New Boston above normal Kankakee River at Momence much above normal 4 30 Iroquois River near Chebanse above normal Fox River at Dayton above normal Vermilion River at Pontiac above normal Spoon River at Seville much above normal 4 30 LaMoine River at Ripley above normal Bear Creek near Marceline much above normal 9 30 Mackinaw River near Congerville much above normal 8 30 Salt Creek near Greenview above normal Sangamon River at Monticello above normal South Fork Sangamon near Rochester above normal Illinois River at Valley City 26, ,530 36,850 33,570 much above normal 8 30 Macoupin Creek near Kane normal Vermilion River near Danville above normal Kaskaskia River at Vandalia above normal Shoal Creek near Breese above normal Embarras River at Ste. Marie above normal Skillet Fork at Wayne City much above normal 2 30 Little Wabash below Clay City above normal Big Muddy at Plumfield normal Cache River at Forman above normal Notes: Source streamflow data is obtained from the U.S. Geological Survey. N/A = not available. Much below normal flow = % chance of exceedence. Below normal flow = 70-90% chance of exceedence. Normal flow = 30-70% chance of exceedence. Above normal flow = 10-30% chance of exceedence. Much above normal flow = 0-10% chance of exceedence. *As reported in U.S. Geological Survey (USGS) Water Resources Data, Illinois, Water Year

9 Table 5. Reservoir Levels in Illinois, April 2009 Current level Average March Normal pool difference from Monthly difference from Years reported or target normal or target change normal or target of pumpage Reservoir County level (feet) (feet) (feet) (feet) record (million gallons) Altamont Effingham Bloomington McLean No pumpage Canton Fulton Carlinville Macoupin Carlyle (1) Clinton N/A Coulterville Randolph N/A N/A N/A Decatur (1,3) Macon Evergree n(4 ) Woodford Glenn Shoals (2) Montgomery w/hillsboro Greenfield Greene Highland Madison Hillsboro (2) Montgomery N/A Jacksonville (2) Morgan w/mauvaise Terre Kinkaid Jackson Lake of Egypt Williamson N/A N/A N/A Mattoon Coles w/paradise Mauvaise Terre (2) Morgan no meter Mt. Olive (new) Macoupin w/mt. Olive (old) Mt. Olive (old) Macoupin Nashville (3) Washington Pana Christian N/A Paradise Coles Paris (east) Edgar Paris (west) Edgar w/paris (east) Pinckneyville Perry Pittsfield Pike Raccoon (1) Marion N/A N/A Rend Franklin N/A Salem (3) Marion Shelbyville (1) Shelby Not PWS Sparta (3) Randolph Spring (4) McDonough Springfield (1,3) Sangamon Taylorville Christian Vermilion (4) Vermilion Virginia Cass Not PWS Notes: Normal pool and target level datum is NGVD Current levels reported represent water surface levels at the end of the month, not the monthly average. Average difference from normal or target level is the arithmetic average of reported month-end values for the period of record indicated. Years of record = total number of monthly readings included in month-end average. Total period of record may be longer. Not PWS = not a public water supply. N/A = not available. (1) Target operating level may vary. Seasonal target levels this month represent May 1 values. (2) Instrumentation not available to measure height of water elevation above spillway. (3) Natural inflow can be supplemented by other sources. (4) Normal pool elevations have changed during period of record reported. 9

10 Groundwater Information (Ken Hlinka) Comparison to Average Levels. Shallow groundwater levels in 16 observation wells, which are remote from pumping centers, were above average for the month. April levels were 2.5 feet above normal and ranged from 0.3 feet below to 12.1 feet above normal levels (Table 6). Comparison to Previous Month. Shallow groundwater levels were above those of last month. Levels averaged 1.0 foot higher and ranged from 0.5 feet below to 4.5 feet above levels of last month. Comparison to Same Month, Previous Year. Shallow groundwater levels in April were above levels measured one year ago. Levels averaged 1.3 feet higher and ranged from 4.4 feet below to 6.0 feet above than during April Table 6. Month-End Shallow Groundwater Level Data Sites, April 2009 Number Well name County Well depth (feet) This month s reading (depth to water, feet) 15-year avg. level (feet) Deviation from Period of record avg. (feet) Previous month (feet) Previous year (feet) 1 Galena JoDaviess Mt. Morris Ogle Crystal Lake McHenry Cambridge Henry *3.97 N/A N/A N/A N/A 5 Fermi Lab DuPage Good Hope McDonough Snicarte Mason Coffman Pike Greenfield Greene Janesville Cumberland St. Peter Fayette SWS #2 St. Clair Boyleston Wayne Sparta Randolph SE College Saline Dixon Springs Pope Bondville Champaign Notes: * Data not used in analysis N/A - Data not available. Averages Addendum (Nancy Westcott) Imperial Valley Precipitation. April 2009 precipitation amounts (Figure 5a) continued to be heavy. Monthly gage totals were greatest in the northern portion of the network, and precipitation was lightest in the southeastern region. Individual gage amounts ranged from 7.77 inches at Site #2 to 4.61 inches at Site #23. The 30-year, , average precipitation amounts for April at Havana and Mason City are 3.45 and 3.34 inches, respectively. The April 2009 network average of 6.01 inches is about 179 percent of the 16-year ( ) IVWA April network average of 3.35 inches. Cook County Precipitation. April 2009 precipitation amounts (Figure 5b) also continued to be above average. The greatest precipitation was found in the south-central region of the county, and the lightest precipitation was in the northern portion of the network. Precipitation values ranged from 7.16 inches at Site #17 (Alsip) to 3.67 inches at Site #2 (Winnetka). The April 2009 network average of 5.09 inches is about 148 percent of the 19-year ( ) April network average of 3.43 inches. 10

11 a. Imperial Valley b. Cook County Figure 5. Long-term raingage network precipitation totals (inches) for April 2009 Data sources for information in this publication include the following: CPC - Climate Predication Center, ISWS - Illinois State Water Survey, MRCC - Midwestern Regional Climate Center, NCDC - National Climate Data Center, NWS - National Weather Service, USACE - U.S. Army Corp of Engineers, USGS - U.S. Geological Survey, WARM - Water and Atmospheric Resources Monitoring Program, 11