ILLINOIS WATER AND CLIMATE SUMMARY

Transcription

1 ILLINOIS WATER AND CLIMATE SUMMARY July 2015 Figure 1 Statewide departures from normal JULY 2015 OVERVIEW s were below and precipitation was above the long-term average in Illinois during July. Mean streamflow statewide was well above the median for the month. Shallow groundwater levels were above longterm average depths. s for July averaged 74.4 degrees F, 0.9 degrees below the long-term average (Figure 1). The highest temperatures were in the southeastern and southwestern crop reporting districts (CRDs) with monthly averages of 78.4 degrees. The lowest were in the northeastern and northwestern CRDs, with both having a monthly average of 71.6 degrees. Precipitation averaged 5.20 inches, 1.11 inches above normal for the month (Figure 1). Crop reporting district totals ranged from 7.58 inches in the western district to 3.23 inches in the east southeastern CRD. Soil moisture levels at depths of 2 to 8 inches showed an overall decline in July. Levels at 2 inches decreased 35 percent from their peak on July 9 to the end of the month. Soil moisture remained high at the deeper depths with levels at 39 and 59 inches averaging 0.45 water fraction by volume (wfv) on July 31. Mean provisional streamflow aggregated statewide was well above the long-term median flow for July, about 610 percent of median (Figure 1). Monthly mean discharge values were much above normal throughout most of Illinois, including the highest on record for July at some gage locations. River levels remained above local flood stages through most of the month on the Illinois River below the Fox River, on the Mississippi River below the Illinois River, and at the lower end of the Ohio River. At some locations, the Illinois River and Mississippi River remained above the flood stage throughout the entire month. Water surface levels at the end of July were below full pool/target operating levels at six of 29 reporting reservoirs. At the end of July, Rend Lake was 4.0 feet above the spillway level, Carlyle Lake was 5.9 feet above the summer target level, and Lake Shelbyville was 3.5 feet above the summer target level. Lake Michigan s water level was above its long-term mean for the month. Shallow groundwater levels statewide were above normal this month with an average departure of +2.1 feet (Figure 1). A decrease of 0.6 feet in departure was observed from the deviation in normal groundwater levels between June and July. Levels averaged 1.5 feet below June levels and were 2.7 feet above July levels of last year. Water and Atmospheric Resources Monitoring Program Contact Jennie R. Atkins: (217) , jatkins@illinois.edu

2 WEATHER/CLIMATE INFORMATION Jim Angel and Jennie Atkins The following description of precipitation, temperature, and snowfall (in winter) comes from data compiled by a number of networks that report to the National Oceanic and Atmospheric Administration (NOAA). There are more than 650 reporting sites in Illinois alone. These data are provisional and may change slightly over time. Precipitation averaged 5.20 inches in July, 1.11 inches above the long-term average. However, rainfall totals varied greatly across the state. Some of the highest totals were recorded in western Illinois with Winchester in Scott County having the highest total at inches. White Hall in neighboring Green County recorded inches. In contrast, portions of northwestern and east-central Illinois reported less than 2 inches for the month. Galena in Jo Daviess County recorded 1.31 inches for July, while Tuscola in Douglas County and Shelbyville in Shelby County reported 1.50 and 1.11 inches, respectively. Illinois received inches of rain from May 1 through July 31, 7.26 inches above the long-term average for the period. This makes 2015 the wettest May July in the 120-year record for the state and 1990 tied for the next wettest with inches. The state received inches from January through July 2015, 5.25 inches above the long-term average, making 2015 the 14th wettest January July on record. s were slightly warmer than normal, averaging 74.4 degrees F, or 0.9 degrees above the long-term average. The University of Illinois Northern Illinois Agronomy Research Center in DeKalb County had the lowest average temperature for the month with 69.2 degrees. The highest average, 80.7 degrees, was at the Kaskaskia Lock and Dam in Randolph County. Growing degree days (base 50 degrees) for May July ranged from less than 1600 degree days (DD) in northern Illinois to more than 2000 in the southern third of the state. Degree day totals are near normal for most of northern and central Illinois. Totals from 50 to 150 DD above the long-term average are seen for the southern and east-central parts of the state. The US Drought Monitor listed no part of the state as in drought or abnormally dry in their July 28 report. ILLINOIS CLIMATE NETWORK (ICN) Jennie Atkins The Illinois Climate Network (ICN) consists of 19 stations across the state which collect hourly weather and soil information. ICN data for July are presented in Table 1. Wind speeds averaged 4.4 mph in July, 1.1 mph less than in June and 0.5 mph less than the network s long-term average. The Stelle station had the highest monthly average at 6.3 mph. The highest wind gust was 49.3 mph, measured at Perry on July 13. Air temperatures increased 2.4 degrees from June to an average of 74.6 degrees for the month. The highest temperature, 96.6 degrees, was measured at the Rend Lake station on July 28. The lowest temperature for the month was 48.3 degrees, recorded at DeKalb on July 2. Increases were also seen in soil temperatures with network averages 3 to 5 degrees above those from June. s at depths of 2 inches under bare soil averaged from 76.9 to 83.6 degrees, though temperatures of 100 degrees or higher were recorded at several stations. s at 4 inches averaged 0.5 degrees less with station averages ranging from 75.8 to 83.4 degrees. s under sod also increased in July. State averages at 4 inches ranged from 71.0 to 81.7 degrees. s were slightly cooler at 8 inches with averages from 71.1 to 80.9 degrees. Precipitation totals varied greatly across the ICN, ranging from 2.56 inches at Olney to inches at the Perry station. The network average for the month was 5.48 inches, 2.09 inches above the long-term average. Soil moisture levels, overall, declined at the 2- to 8-inch depths in July. Levels at 2 inches peaked on July 9 with an average of 0.41 water fraction by volume (wfv). They steadily declined over the remainder of the month to an average of 0.27 wfv on July 31. Similar patterns were observed at 4- and 8-inch depths, ending the month with network averages of 0.30 and 0.31 wfv, respectively. No significant changes were observed at 20 inches. Levels remained high at 39 and 59 inches with no significant changes at either depth over the course of the month. On July 31, network averages at both depths were 0.45 wfv. Hourly and daily weather and soil data for all ICN stations are available on the WARM website at For more information or data requests, please contact WARM Program Manager Jennie Atkins. 2

3 Figure 2a Illinois precipitation, temperature and their departures from average for July Source: cli-mate, Midwestern Regional Climate Center. accessed on: August 4, 2015 Figure 2b Illinois growing degree days and departure from average for May July Source: Midwestern Regional Climate Center. accessed on: August 4,

4 Figure 3 Illinois precipitation and precipitation departure from average for year to date (top), last 6 months (middle), and last 3 months (bottom) Source: cli-mate, Midwestern Regional Climate Center. accessed on:august 4,

5 Table 1. Data from the Illinois Climate Network (ICN), July 2015 Freeport Station Ave Wind Speed (mph) Ave Wind Direction ( ) Maximum Wind Gust (mph) Maximum Air ( F) Minimum Air ( F) Average Air ( F) Big Bend St Charles DeKalb Belleville Big Bend Bondville Brownstown Carbondale Champaign DeKalb Dixon Springs Fairfield Freeport Kilbourne Monmouth Olney Peoria Perry M Rend Lake Springfield St. Charles Stelle Monmouth Perry Kilbourne Springfield Belleville Peoria Brownstown Stelle Champaign Bondville Fairfield Rend Lake Carbondale Dixon Springs Olney Table 1 continued Station Total Solar Radiation (MJ/m 2 ) Average Relative Humidity (%) Total Precipitation (in) Average Dew Point ( F) Total Potential Evapotranspiration (in) Ave Soil at 4" under Sod ( F) Ave Soil at 8" under Sod ( F) Ave Soil at 2" under Bare Soil ( F) Ave Soil at 4" under Bare Soil ( F) Belleville Big Bend Bondville Brownstown Carbondale Champaign DeKalb Dixon Springs Fairfield Freeport Kilbourne Monmouth Olney Peoria Perry M M Rend Lake Springfield St. Charles Stelle Notes: M = Missing data. 5

6 *The 20 cm (8 in) sensor failed at Monmouth on July 24. Figure 4 July soil moisture levels at ICN stations. 5 cm (2 in), 10 cm (4 in), and 20 cm (8 in) 6

7 Figure 4 July soil moisture levels at ICN stations. 5 cm (2 in), 10 cm (4 in), and 20 cm (8 in) 7

8 SURFACE WATER INFORMATION Bill Saylor 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. Peak stage is represented here by morning readings posted daily by the USACE or the National Weather Service. The flood stage is defined locally for each gage location. Illinois River water levels remained above local flood stages through most of month from the confluence of the Fox River downstream to Peoria, and remained above local flood stages through the entire month from Havana downstream to the Mississippi River. Mississippi River water levels exceeded local flood stages occasionally during July from Quincy downstream to the confluence of the Illinois River, and throughout most of the month along the Illinois border below the confluence of the Illinois River. The Mississippi River remained above local flood stages throughout the entire month at Grafton (at the confluence of the Illinois River) and from Chester to Cape Girardeau, Missouri. The Ohio River remained above the flood stage for most of the month at Cairo (and at Metropolis). 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 July 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 aggregated statewide was well above the median value for July (approximately 610 percent of the median) and well above the longterm mean for the month (about 400 percent of the mean). Monthly mean discharge values were much above normal throughout much of Illinois. Of Table 2 streamgage locations, the estimated monthly mean flows this month were the highest during the gage record for the month of July at the following streamgages: Kankakee River at Momence, Iroquois River near Chebanse, Salt Creek at Greenview (Sangamon River watershed), Macoupin Creek near Kane, and the Illinois River at Valley City. The monthly mean flow of the Illinois River at Valley City this month was the second highest estimated by USGS for any month during the period of record of the station (76 years), slightly less than the highest monthly mean flow of 94,940 cfs in March 1985, and slightly higher than the third highest monthly mean flow of 93,800 cfs in April 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-june water levels at 29 reservoirs for which levels were reported last month and this month, reported end-of-july water levels were lower at 22 reservoirs, higher at one reservoir, and about the same as at the end of last month at six reservoirs. For the 29 reservoirs with measurements reported at the end of July, water levels were below normal target pool or spillway level at six reservoirs, at about full pool level at 15 reservoirs, and above seasonal target or fixed spillway levels at eight reservoirs. Major Reservoirs. Compared to water levels at the end of June, at the end of July the water level at Rend Lake was 1.5 feet lower, Carlyle Lake level was 3.4 feet lower, and Lake Shelbyville was 6.9 feet lower. At the end of July, Rend Lake was 4.0 feet above the spillway level, Carlyle Lake was 5.9 feet above the summer target level, and Lake Shelbyville was 3.5 feet above the summer target level. Surface Water Information continued on page 11 8

9 Table 2. Peak Stages for Major Rivers during July 2015 River Station River mile* Flood stage (feet)* Peak stage (feet)** Date Illinois Morris La Salle Peoria Havana Beardstown Hardin Mississippi Dubuque Keokuk Quincy ,13 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, July 2015 Station Drainage area (sq mi) Years of record 2015 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 above normal Pecatonica River at Freeport above normal Green River near Geneseo much above normal Edwards River near New Boston much above normal 5 31 Kankakee River at Momence much above normal 1 31 Iroquois River near Chebanse , much above normal 1 31 Fox River at Dayton much above normal 9 31 Vermilion River at Pontiac much above normal 3 31 Spoon River at Seville much above normal 5 31 LaMoine River at Ripley much above normal 3 31 Bear Creek near Marceline much above normal 7 31 Mackinaw River near Congerville much above normal 3 31 Salt Creek near Greenview much above normal 1 31 Sangamon River at Monticello much above normal 4 31 South Fork Sangamon near Rochester much above normal 4 31 Illinois River at Valley City 26, ,060 21,830 19,326 much above normal 1 31 Macoupin Creek near Kane much above normal 1 31 Vermilion River near Danville much above normal 7 31 Kaskaskia River at Vandalia much above normal 7 31 Shoal Creek near Breese above normal Embarras River at Ste. Marie above normal Skillet Fork at Wayne City much above normal Little Wabash below Clay City much above normal 9 31 Big Muddy at Plumfield much above normal 4 31 Cache River at Forman much above normal 2 31 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

10 Table 4. Reservoir Levels in Illinois, July 2015 Normal pool Current level Monthly Average difference Years June 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 Carlinville Macoupin Carlyle (1) Clinton 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 Jacksonville (2) Morgan w/mauvaise Terre Kinkaid Jackson Lake of Egypt Williamson N/A Mattoon Coles w/paradise Mauvaise Terre (2) Morgan no meter Mt. Olive (new) Macoupin w/mt. Olive (old) Mt. Olive (old) Macoupin Pana Christian N/A Paradise Coles Paris (east) Edgar Not PWS Paris (west) Edgar w/paris (east) 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 (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 August 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. 10

11 Surface Water Information continued from page 8 Great Lakes. Current month mean and endof-month values are provisional and are relative to International Great Lakes Datum The July 2015 mean level for Lake Michigan was feet. The monthly mean level one year ago (July 2014) was feet. The long-term average lake level for July is feet, based on data. In this period of record, the lowest mean level for Lake Michigan for July occurred in 1964 at feet, and the highest level for July occurred in 1986 at feet. The month-end level of Lake Michigan was feet. All values are provided by the U.S. Army Corps of Engineers Detroit District. GROUNDWATER INFORMATION Ken Hlinka Comparison to Average Levels. Shallow groundwater levels in 14 observation wells, which are remote from pumping centers, were above normal for the month of July. Levels averaged 2.1 feet above and ranged from 0.5 feet below to 9.9 feet above normal levels (Table 5). Comparison to Previous Month. Shallow groundwater levels were below those of the previous month. Levels averaged 1.5 feet below and ranged from 4.8 feet below to 1.5 feet above levels of June. Comparison to Same Month, Previous Year. Shallow groundwater levels in July were above levels measured one year ago. Levels averaged 2.7 feet above this month and ranged from 0.4 feet below to 10.5 feet above levels of July Table 5. Month-End Shallow Groundwater Level Data Sites, July 2015 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 NA 2 Mt. Morris Ogle Crystal Lake McHenry Fermi Lab DuPage Good Hope McDonough NA NA NA NA NA 6 Snicarte Mason Coffman Pike Greenfield Greene Janesville Coles St. Peter Fayette SWS #2 St. Clair Boyleston Wayne NA 13 Sparta Randolph NA 14 SE College Saline Bondville Champaign Notes: N/A = Data not available. Averages

12 ADDENDUM Nancy Westcott Imperial Valley. Precipitation during July 2015 was above normal. Monthly gage totals were largest in the far northeastern portion of the network, and smallest in the central region. Individual gage amounts ranged from 8.84 inches at Site #3 to 4.01 inches at Site #6. The , 30-year average precipitation amounts for July at Havana and Mason City are 4.04 and 4.60 inches, respectively. The July 2015 network average of 5.40 inches is about 149 percent of the 22-year ( ) IVWA July network average of 3.62 inches. Cook County. The July 2015 total precipitation was moderate (Figure 5b). Precipitation amounts were greatest in the far northern portion of the network, and least in the central region. Precipitation values ranged from 3.28 inches at Site #2 (Winnetka) to 1.29 inches at Site #11 (LaGrange). The July 2015 network average of 2.18 inches is about 91 percent of the 25-year ( ) July network average of 3.65 inches. a. Imperial Valley b. Cook County Figure 5 Long-term raingage network precipitation totals (inches) for July 2015 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)