ILLINOIS WATER AND CLIMATE SUMMARY

Transcription

1 ILLINOIS WATER AND CLIMATE SUMMARY April 2012 Figure 1 Statewide departures from normal APRIL 2012 OVERVIEW Temperatures in Illinois were above normal and precipitation was below normal during April. Mean streamflows were below median values for the month. Shallow groundwater levels were below long-term average depths. Temperatures across Illinois for April were above normal (Figure 1). The statewide average of 54.2 F was 2.0 degrees above normal. Crop Reporting District (CRD) temperatures ranged from 1.1 degrees above normal (Northeast CRD) to 2.9 degrees above normal (Southeast CRD). Precipitation amounts for Illinois in April were below normal (Figure 1). The statewide average of 3.32 inches represented a 0.48-inch deficit or 87 percent of average for the month. The East-Central CRD received the least amount of rainfall, 2.29 inches (65 percent of average), while the West- Southwest CRD recorded the greatest rainfall total with 5.81 inches (153 percent of average). Soil moisture levels varied across the state. Levels increased in the central portion of the state with significant overall monthly increases at Champaign, Perry, and Springfield. Soil moisture levels declined significantly at the southern stations of Carbondale, Dixon Springs, and Rend Lake and the northern station of St. Charles. Mean provisional streamflow statewide was below the median flow in April, about 40 percent of median (Figure 1). Rivers throughout Illinois recorded monthly mean discharges ranging from much below normal to normal for April. Monthly mean streamflows at three of the sample stations were the lowest on record for April. Water surface levels at the end of April were below the full pool/ target operating level at 10 of 26 reporting reservoirs. At the end of April, Rend Lake was 2.4 feet above spillway level, Lake Shelbyville was 3.1 feet below the May 1 target level, and Carlyle Lake was 0.1 foot above the May 1 target level. Shallow groundwater levels statewide were below normal with an average departure of -1.0 foot. Combined with the change in normal monthly groundwater levels between March and April, an increase of 0.2 feet in departures was observed from last month (Figure 1). Levels averaged just above (0.02 feet) March levels and were approximately 3.0 feet below April levels of last year. Water and Atmospheric Resources Monitoring Program Contact Jennie R. Atkins: (217) , jatkins@illinois.edu

2 WEATHER/CLIMATE INFORMATION Jim Angel Temperatures across Illinois for April were above normal. The warmest reading for the month was 92 F at Kaskaskia on April 2 and at Jacksonville and Pana on April 3. The coldest reading for the month was 23 F at Jerseyville on April 17. This was the warmest January April (4 months and year-to-date) and the warmest May April (12 months) on record. Precipitation for April was below normal statewide (Figure 2). The wettest areas were in west-southwest Illinois near St. Louis. Belleville reported the highest monthly total with 8.64 inches of precipitation. ILLINOIS CLIMATE NETWORK (ICN) Jennie Atkins The Illinois Climate Network (ICN) consists of 19 stations across the state that collect hourly climate and soil information. Data from April are presented in Table 1. April s average wind speeds decreased 15 percent in comparison to March. Station averages ranged from 3.7 mph in Dixon Springs to 13.3 mph in Bondville. The highest wind gust, 58.0 mph, was recorded at Belleville on April 28. Air temperatures across the network increased slightly in April, averaging 55.9 F. The lowest temperature of the month, 22.2 F, was recorded at Bondville on April 11. The highest temperature, 89.1 F, was recorded on April 2 at Rend Lake (Ina). Soil temperatures increased an average of 5 F from March. Temperatures were highest in the southern portion of the network with monthly averages of 60.8 F at 4-inch depths under sod, 61.0 F at 8-inch depths under sod, and 61.8 F at 4-inch depths under bare soil. Soil temperatures in central Illinois averaged 56.8 F at 4-inch depths under sod, 57.1 F at 8-inch depths under sod, and 57.9 F at 4-inch depths under bare soil. The lowest temperatures were recorded in the north with average temperatures of 53.0 F at 4-inch depths under sod, 52.4 F at 8-inch depths under sod, and 55.5 F at 4-inch depths under bare soil. Precipitation totals increased at most ICN stations in April, averaging 3.45 inches. Station totals ranged from 1.39 inches in Dixon Springs to 8.56 inches in Belleville. Soil moisture levels, along with precipitation, varied greatly across the network. Significant monthly increases were observed in levels at Belleville, Champaign, Perry, and Springfield. Significant decreases were observed in the southern stations at Carbondale, Dixon Springs, and Rend Lake (Ina) as well as the northern station of St. Charles. Soil moisture plots for each station are presented in Figure 4. Figure 2 Illinois precipitation and precipitation departure from average for April

3 Figure 3 Illinois precipitation and precipitation departure from average for year to date (top), last 6 months (middle), and last 3 months (bottom) 3

4 Monmouth Perry Freeport Big Bend Kilbourne Springfield Belleville Peoria St Charles DeKalb Brownstown Stelle Champaign Bondville Fairfield Rend Lake Carbondale Dixon Springs Olney Table 1. Data from the Illinois Climate Network (ICN), April 2012 Station Ave Wind Speed (mph) 4 Ave Wind Direction ( ) Maximum Wind Gust (mph) Maximum Air Temperature Minimum Air Temperature Average Air Temperature Total Solar Radiation (MJ/m 2 ) Belleville Big Bend Bondville Brownstown Carbondale Champaign DeKalb Dixon Springs Fairfield Freeport Kilbourne Monmouth Olney Peoria Perry (Orr) Rend Lake (Ina) Springfield St. Charles Stelle Table 1 continued Station Average Relative Humidity (%) Total Precipitation (in) Average Dew Point Total Potential Evapotranspiration (in) Ave Soil Temperature at 4" under Sod Ave Soil Temperature at 8" under Sod Ave Soil Temperature at 4" under Bare Soil Belleville Big Bend Bondville Brownstown Carbondale Champaign DeKalb Dixon Springs Fairfield Freeport Kilbourne Monmouth Olney Peoria Perry (Orr) Rend Lake (Ina) Springfield St. Charles Stelle

5 Figure 4 April soil moisture levels at ICN stations. 5 cm (2 in), 10 cm (4 in), and 20 cm (8 in) 5

6 Figure 4 continued April soil moisture levels at ICN stations. 5 cm (2 in), 10 cm (4 in), and 20 cm (8 in) 6

7 SURFACE WATER INFORMATION Bill Saylor and Amy Russell 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, the Illinois State Water Survey (ISWS), and the USACE. Provisional discharge data are obtained from the USGS. Table 2 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 and/or the USACE. Peak stages recorded in April on these rivers did not exceed local flood stages at gage locations. Provisional monthly mean flows for 26 streamgaging stations located throughout Illinois are shown in Table 3. 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 3 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 3 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 3 contribute to their flow.) Mean provisional flow statewide was below the median value for April (about 40 percent of the median) and below the long-term mean for the month (about 33 percent of the mean). Monthly mean streamflow conditions throughout Illinois, as represented by Table 3 stations, ranged from much below normal to normal for April. Monthly mean streamflow for April 2012 was the lowest recorded for the month of April for the Iroquois River near Chebanse and for the Cache River at Forman, both with nearly 90 years of record. Monthly mean streamflow for April 2012 was the lowest recorded for the month of April for the Sangamon River at Monticello in approximately 100 years of record. Water-Supply Lakes and Major Reservoirs. Table 4 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 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 4), 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 24 reservoirs, reported end-of-april water levels were lower at seven reservoirs, higher at 12 reservoirs, and at about the same level at five reservoirs. For the 26 reservoirs with measurements reported at the end of April, water levels at 10 reservoirs were below normal target pool or spillway level, nine lakes were at spillway level, and seven reservoirs were above spillway or normal target level. Note that some lake level reports this month reflect precipitation during the week of April 30. Major Reservoirs. Compared to water levels at the end of March, at the end of April, the Rend Lake water level was 0.7 feet lower, Carlyle Lake was 1.7 feet higher, and Lake Shelbyville was 2.2 feet higher. At the end of April, Rend Lake was 2.4 feet above spillway level, Lake Shelbyville was 3.1 feet below May 1 target level, and Carlyle Lake was 0.1 foot above May 1 target level. (Lake Shelbyville and Carlyle Lake target levels increase from March to May.) Great Lakes. Current month mean and endof-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 2. Peak Stages for Major Rivers during April 2012 River Station River mile* Flood stage (feet)* Peak stage (feet)** Date Illinois 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. Table 3. Provisional Mean Flows, April 2012 Station Drainage area (sq mi) Years of record 2012 mean flow (cfs) Long-term flows Mean* Median (cfs) (cfs) Flow condition Percent chance of exceedence Days of data this month Rock River at Rockton below normal Rock River near Joslin ,050 10,075 below normal Pecatonica River at Freeport normal Green River near Geneseo below normal Edwards River near New Boston much below normal Kankakee River at Momence much below normal Iroquois River near Chebanse much below normal Fox River at Dayton below normal Vermilion River at Pontiac much below normal Spoon River at Seville below normal LaMoine River at Ripley much below normal Bear Creek near Marceline below normal Mackinaw River near Congerville much below normal Salt Creek near Greenview much below normal Sangamon River at Monticello much below normal South Fork Sangamon near Rochester below normal Illinois River at Valley City 26, ,630 37,490 33,795 much below normal Macoupin Creek near Kane normal Vermilion River near Danville much below normal Kaskaskia River at Vandalia below normal Shoal Creek near Breese normal Embarras River at Ste. Marie below normal Skillet Fork at Wayne City normal Little Wabash below Clay City below normal Big Muddy at Plumfield below normal Cache River at Forman much below normal Notes: Source streamflow data are obtained from the U.S. Geological Survey N/A = not available (due to ice or equipment problems). 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 4. Reservoir Levels in Illinois, April 2012 Normal pool Current level Monthly Average difference Years March or target difference from normal change from normal of reported pumpage Reservoir County level (feet) or target (feet) (feet) or target (feet) record (million gallons) Altamont Effingham Bloomington McLean N/A Canton Fulton Carlinville Macoupin Carlyle (1) Clinton N/A Coulterville Randolph N/A N/A N/A Decatur (1,3) Macon ,049.9 Evergreen (4) Woodford N/A Glenn Shoals (2) Montgomery N/A N/A w/hillsboro Greenfield Greene N/A N/A Highland Madison Hillsboro (2) Montgomery N/A N/A Jacksonville (2) Morgan N/A w/mauvaise Terre Kinkaid Jackson Lake of Egypt Williamson N/A Mattoon Coles w/paradise Mauvaise Terre (2) Morgan N/A no meter Mt. Olive (new) Macoupin N/A N/A w/mt. Olive (old) Mt. Olive (old) Macoupin Nashville (3) Washington N/A N/A Pana Christian N/A Paradise Coles Paris (east) Edgar Not PWS Paris (west) Edgar w/paris (east) Pinckneyville Perry N/A N/A N/A Raccoon (1) Marion N/A N/A Rend Franklin N/A Salem (3) Marion Shelbyville (1) Shelby Not PWS Sparta (3) Randolph N/A Spring (4) McDonough N/A N/A Springfield (1,3) Sangamon Taylorville Christian Vermilion (4) Vermilion 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 15 observation wells, which are remote from pumping centers, were below average for the month of April. Levels were 1.0 foot below normal and ranged from 6.8 feet below to 2.5 feet above normal levels (Table 6). The dry conditions throughout the state persist with three wells in Bondville (Champaign Co.), Fermi Lab (DuPage Co.), and SE College (Saline Co.), all reporting their lowest reading on record for April. Comparison to Previous Month. Shallow groundwater levels were slightly above those of last month. Levels averaged 0.02 feet above and ranged from 2.2 feet below to 3.4 feet above levels of last month. Comparison to Same Month, Previous Year. Shallow groundwater levels in April were below levels measured one year ago. Levels this month averaged 3.0 feet below and ranged from 7.3 feet below to 0.3 feet below levels of April Table 5. Month-End Shallow Groundwater Level Data Sites, April 2012 Number Well name County Well depth (feet) This month s reading (depth to water, feet) 15-year avg. level (feet) Period of record avg. (feet) Deviation from Previous month (feet) Previous year (feet) 1 Galena JoDaviess Mt. Morris Ogle Crystal Lake McHenry Cambridge Henry * NA NA NA NA 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 ** Bondville Champaign ** Notes: N/A = Data not available. *Data not used in analysis. ** Lowest reading reported for April for the period of record Averages

11 ADDENDUM Nancy Westcott Imperial Valley. Precipitation for April 2012 was light (Figure 5a). Monthly gage totals were largest in the western portion of the network, and smallest in the central region of the network. Individual gage amounts ranged from 3.53 inches at Site #4 to 1.52 inches at Site #15. The , 30-year average precipitation amounts for April at Havana and Mason City are 3.67 and 3.61 inches, respectively. The April 2012 network average of 2.09 inches is about 58 percent of the 19-year ( ) IVWA April network average of 3.60 inches. Cook County. April 2012 total precipitation was also light (Figure 5b). Precipitation amounts were greatest in the central portion of the network, and least in the southern region. Precipitation values ranged from 2.91 inches at Site #10 (near S. Halsted and W. 26th) to 0.92 inches at Site #24 (Matteson). The April 2012 network average of 1.81 inches is about 51 percent of the 22- year ( ) April network average of 3.58 inches. a. Imperial Valley b. Cook County Figure 5 Long-term raingage network precipitation totals (inches) for April 2012 Data sources for information in this publication include the following: CPC - Climate Prediction Center, ISWS - Illinois State Water Survey, MRCC - Midwestern Regional Climate Center, NCDC - National Climatic Data Center, NWS - National Weather Service, USACE - U.S. Army Corps of Engineers, USGS - U.S. Geological Survey, WARM - Water and Atmospheric Resources Monitoring Program, Illinois State Water Survey 2204 Griffith Drive Champaign, IL Tel (217)