ILLINOIS WATER AND CLIMATE SUMMARY

Transcription

1 ILLINOIS WATER AND CLIMATE SUMMARY October 2012 OCTOBER 2012 OVERVIEW Temperatures in Illinois were below normal during October, and precipitation was above normal. Mean streamflows were slightly above median for the month. Shallow groundwater levels were below long-term average depths. Temperatures across Illinois for October were below normal (Figure 1). The statewide average of 52.3 F was 2.4 F below normal. Crop Reporting District (CRD) temperatures ranged from 2.1 F below normal (Northeast and Southeast CRD) to 2.8 F below normal (East-Southeast CRD). Precipitation amounts for Illinois in October were above normal (Figure 1). The statewide average of 3.95 inches represented a 1.04-inch surplus or 136 percent of normal for the month. The Northwest CRD received the least precipitation with 3.21 inches (112 percent of average), while the East-Central CRD received the most precipitation with 4.84 inches (168 percent of average). Soil moisture improved in northern and central Illinois at 2-, 4-, and 8-inch depths. No significant changes were observed in the southern portion of the state. Mean provisional streamflow aggregated statewide was slightly above the median flow in October, about 110 percent of median (Figure 1). Rivers throughout Illinois recorded monthly mean discharges primarily in the below normal to above normal range. Water surface levels at the end of October were below full pool/target operating level at 20 of 26 reporting reservoirs. At the end of October, Rend Lake was 0.1 foot above spillway level, Lake Shelbyville was 0.5 feet below seasonal target level, and Carlyle Lake was 2.6 feet above seasonal target level. Shallow groundwater levels statewide were below normal with an average departure of -1.3 feet. There was no difference between September and October departures from normal groundwater levels (Figure 1). Levels averaged 0.3 feet below September levels and were approximately 1.4 feet below October levels of last year. Figure 1 Statewide departures from normal Water and Atmospheric Resources Monitoring Program Contact Jennie R. Atkins: (217) , jatkins@illinois.edu

2 WEATHER/CLIMATE INFORMATION Jim Angel Temperatures across Illinois for October were below normal. The average daily high temperatures ranged from the upper 50s in northern Illinois to the upper 60s in southern Illinois. The average daily low temperatures ranged from the upper 30s in much of northern Illinois to the 40s in the rest of the state. Despite the cool October, the January-October statewide average temperature of 58.9 F was 3.4 F above normal and the second warmest on record. The warmest on record of was 1921 with 59.2 F. Precipitation for October was 3.95 inches, 1.04 inches wetter than normal (Figure 2). The wettest area of the state was between Quincy and Champaign where precipitation totals ranged from 4 to over 7 inches. For example, Jacksonville (IL-MG-7) reported 7.24 inches. Several sites in Logan County reported over 6 inches of precipitation, including Lincoln (IL-LG-36) with 6.20 inches and 31 days reported. Meanwhile, some of the driest areas were in southern Illinois, south of I-64, and in northern Illinois, north of I-80. Those areas had precipitation totals of less than 3 inches. For example, Rockford (IL-WN-8) reported only 2.39 inches with 31 days reported. Even with a wet October, the statewide January- October precipitation total of inches was nearly 5.8 inches below normal and the 15th driest on record and virtually tied with The driest was in 1901 with inches. The second driest was 1988 with inches. 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 October are presented in Table 1. Wind speeds at ICN stations averaged 7.5 mph in September. Station averages ranged from 3.7 mph at Dixon Springs to 12.6 mph at Bondville. The highest wind gust, 51.4 mph, was measured at the Stelle station on October 14. Air temperatures averaged 52.1 F in October, 11.7 F lower than in September. The highest temperature of the month, 82.3 F, was measured at Belleville on October 4. The lowest, 23.7 F, was measured at Big Bend on October 29. Soil temperatures continued to decrease in October, falling on average 18 percent from September. Temperatures in the southern portion of the network averaged 57.3 F at depths of 4 inches under bare soil, 59.6 F at 4 inches under sod, and 60.0 F at 8 inches under sod. At the central stations, soil temperatures averaged 54.4 F at 4 inches under bare soil, 57.5 F at 4 inches under sod, and 56.9 F at 8 inches under sod. Temperatures in northern Illinois averaged 53.1 F at 4 inches under bare soil, 54.9 F at 4 inches under sod, and 55.2 F at 8 inches under sod. Station rainfall totals averaged 3.93 inches in October. The northern stations saw large increases in comparison to September with a station average Continued on page 6 Figure 2 Illinois precipitation and precipitation departure from average for October

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 Olney Table 1. Data from the Illinois Climate Network (ICN), October 2012 Station Ave Wind Speed (mph) 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 Rend Lake Carbondale Dixon Springs 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 October soil moisture levels at ICN stations. 5 cm (2 in), 10 cm (4 in), and 20 cm (8 in) 5

6 10cm plots are not available for the Champaign and St. Charles stations due to maintenance issues Figure 4 October soil moisture levels at ICN stations. 5 cm (2 in), 10 cm (4 in), and 20 cm (8 in) Illinois Climate Network contiued from page 2 of 3.5 inches for the region or 1.9 inches more than in September. Station totals averaged 3.5 inches for the southern stations and 4.4 inches for the central stations. The highest total, 6.18 inches, was measured at Kilbourne. The lowest was measured in Springfield with 2.6 inches. Soil moisture levels at 2-, 4-, and 8-inch depths increased at the northern and central ICN stations over October. Soil moisture levels at the southern stations showed no significant changes at these depths. Moisture levels across the network remained steady at 20-, 39-, and 59-inch depths with changes, on average, of less than 10 percent. Hourly and daily weather and soil data for all ICN stations are available on the WARM website at isws.illinois.edu/warm/soiltemp.asp. 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. The Illinois, Mississippi, and Ohio Rivers did not reach local flood stages this month. 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 October 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 slightly above the median value for October (about 110 percent of the median) and below the long-term mean for the month (about 50 percent of the mean). Monthly mean streamflow conditions throughout Illinois, as represented by Table 3 stations, ranged from below normal to above normal, except at the Green River near Geneseo streamgage in western Illinois where monthly mean flow remained much below normal. 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-september water levels at 25 reservoirs for which levels were reported last month and this month, reported end-of-october water levels were lower at eight reservoirs, higher at 13 reservoirs, and about the same as at the end of last month at four reservoirs. For the 26 reservoirs with measurements reported at the end of October, water levels were below normal target pool or spillway level at 20 reservoirs, above target pool level at two reservoirs (Carlyle Lake and Rend Lake), and at full pool level at four reservoirs. Spring Lake (Macomb) inflow was supplemented by groundwater supply for part of the month. Raccoon Lake level is intentionally drawn down for maintenance work. Major Reservoirs. Compared to water levels at the end of September, at the end of October, Rend Lake water level was slightly higher, Lake Shelbyville was 0.7 feet higher, and Carlyle Lake was 0.7 feet lower. At the end of October, Rend Lake was 0.1 foot above spillway level, Lake Shelbyville was 0.5 feet below seasonal target level, and Carlyle Lake was 2.6 feet above seasonal target level. Great Lakes. Current month mean and endof-month values are provisional and are relative to International Great Lakes Datum The October mean level for Lake Michigan was feet, compared to a mean level of feet in October The long-term average lake level for October is feet, based on data. In the period of record, the lowest mean level for Lake Michigan in October occurred in 1964 at feet, and the highest level for October occurred in 1986 at feet. The month-end level of Lake Michigan was feet. 7

8 Table 2. Peak Stages for Major Rivers during October 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 various St. Louis Chester , 25 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, October 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 normal Rock River near Joslin below normal Pecatonica River at Freeport normal Green River near Geneseo much below normal Edwards River near New Boston normal Kankakee River at Momence normal Iroquois River near Chebanse normal Fox River at Dayton normal Vermilion River at Pontiac normal Spoon River at Seville below normal LaMoine River at Ripley normal Bear Creek near Marceline normal Mackinaw River near Congerville normal Salt Creek near Greenview normal Sangamon River at Monticello above normal South Fork Sangamon near Rochester normal Illinois River at Valley City 26, , normal Macoupin Creek near Kane normal Vermilion River near Danville above normal Kaskaskia River at Vandalia normal Shoal Creek near Breese above normal Embarras River at Ste. Marie below normal Skillet Fork at Wayne City above normal Little Wabash below Clay City normal Big Muddy at Plumfield normal Cache River at Forman 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, October 2012 Normal pool Current level Monthly Average difference Years September 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 N/A Carlinville Macoupin Carlyle (1) Clinton N/A Coulterville Randolph N/A N/A N/A Decatur (1,3) Macon Evergreen (4) Woodford N/A Glenn Shoals (2) Montgomery w/hillsboro Greenfield Greene N/A N/A N/A Highland Madison Hillsboro (2) Montgomery N/A Jacksonville (2) Morgan w/mauvaise Terre Kinkaid Jackson Lake of Egypt Williamson N/A Mattoon Coles N/A N/A w/paradise Mauvaise Terre (2) Morgan 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 N/A N/A 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 N/A N/A Spring (3,4) McDonough 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 November 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 13 observation wells, which are remote from pumping centers, were below average for the month of October. Levels were 1.3 feet below normal and ranged from 4.8 feet below to 2.6 feet above normal levels (Table 5). This month, only Bondville (Champaign Co.) reported its lowest reading on record for the month. Snicarte (Mason Co.) and SE College (Saline Co.) wells reported water levels below the bottom of the well. This is the seventh straight month for a record low level from the SE College well in Saline County. Comparison to Previous Month. Shallow groundwater levels were below those of last month. Levels averaged 0.3 feet below and ranged from 2.3 feet below to 1.2 feet above levels of last month. Comparison to Same Month, Previous Year. Shallow groundwater levels in October were below levels measured one year ago. Levels averaged 1.4 feet below this month and ranged from 7.2 feet below to 3.6 feet above levels of October Table 5. Month-End Shallow Groundwater Level Data Sites, October 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 NA** NA NA NA NA 8 Coffman Pike Greenfield Greene Janesville Coles St. Peter Fayette SWS #2 St. Clair Boyleston Wayne Sparta Randolph SE College Saline NA** NA NA NA NA 16 Bondville Champaign * Averages Notes: N/A = Data not available. * Lowest reading reported in October for the period of record. ** Water level fell below the bottom of the well. *** Water level not used in analysis. 10

11 ADDENDUM Nancy Westcott Imperial Valley. Precipitation for October 2012 was heavy (Figure 5a). Monthly gage totals were largest in the southern portion of the network, and smallest in the northwestern region of the network. Individual gage amounts ranged from 6.15 inches at Site #18 to 3.79 inches at Site #8. The , 30-year average precipitation amounts for October at Havana and Mason City are 3.04 and 2.87 inches, respectively. The October 2012 network average of 4.91 inches is about 191 percent of the 20-year ( ) IVWA October network average of 2.57 inches. Cook County. October 2012 total precipitation was moderate (Figure 5b). Precipitation amounts were greatest in the northern region of the network, and least at locations near Lake Michigan. Precipitation values ranged from 3.72 inches at Site #4 (Skokie) to 1.58 inches at Site #14 (near E. 79th Street and S. Shore Drive). The October 2012 network average of 2.69 inches is about 87 percent of the 23-year ( ) October network average of 3.10 inches. a. Imperial Valley b. Cook County Figure 5 Long-term raingage network precipitation totals (inches) for October 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)