August 2018 ILLINOIS WATER AND CLIMATE SUMMARY AUGUST 2018 OVERVIEW

Transcription

1 August 2018 ILLINOIS WATER AND CLIMATE SUMMARY AUGUST 2018 OVERVIEW Temperatures and precipitation were above the long-term average in Illinois in August. Mean streamflow statewide was above the median for the month. Shallow groundwater levels were above the long-term depths. Air temperatures averaged 74.7 F in July, 1.1 above the long-term average (Figure 1). The southwest crop reporting district (CRD) had the highest temperature with an average of 76.6 F. The lowest regional temperature was 72.6, reported by the northwestern CRD. Precipitation averaged 4.81 inches, 1.25 inches above the long-term average (Figure 1). The western district was the wettest with an average of 6.07 inches. The driest was the eastern CRD with 3.61 inches. Soil moisture increased overall at depths from 2 to 20 inches in August. Moisture levels remained steady at 39 inches and decreased slightly at 59 inches. Mean provisional streamflow aggregated statewide was above the longterm median flow for August, about 170% of median (Figure 1). Monthly mean discharge values primarily ranged from normal to above normal for August, except at some central Illinois streamgage stations where monthly mean flow was below normal. Water surface levels at the end of August were below the full pool or target level at 14 of 26 reporting reservoirs. At the end of August, Lake Shelbyville was 0.3 feet above the summer target level, Carlyle Lake was 0.8 feet above the summer target level, and Rend Lake was 0.9 feet above the spillway level. The Lake Michigan mean level was above its long-term mean for the month. Shallow groundwater levels statewide were above normal this month with an average departure of 0.7 feet (Figure 1). An increase of 0.9 feet in departures was observed from the deviation in normal groundwater levels between July and August. Levels averaged 0.1 foot below July levels and were 0.5 feet above August 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 Table 1a. Temperature and Precipitation for August 2018 JIM ANGEL AND JENNIE ATKINS The following description of temperatures, growing Temp. ( F) Departure from longterm avg. ( ) Precip. (in) Departure from longterm avg. ( ) degree days, precipitation, severe weather, and drought comes from data compiled by a number of networks that report to the National Oceanic and Atmospheric Administration (NOAA). These data are provisional and may change slightly over time. Illinois was warmer and wetter than normal in August. Temperatures averaged 74.7 F, 1.1 above the month s long-term average (Table 1a, Figure 2a). Monthly highs were in the 90s for most stations. The Chicago Botanical Garden reported 97 on August 5, one of the highest temperatures of the month. Station minimums ranged from the 40s to the 60s. August s lowest temperature was 42, reported by the Rochelle station in Ogle County on August 22. Growing degree days (base 50, from April 1) ranged from 2400 in northern Illinois to 3400 DD in the south, 100 to 350 DDs above the long-term averages (Figure 2b). Precipitation averaged 4.81 inches in August, 1.25 inches above the long-term average (Table 1a, Figures 2a, 3). Most of the state saw higher than normal totals with exceptions in parts of east-central and southeast Illinois. The month s largest reported total was inches, recorded at the Arlington Heights station in Cook County. Summer (June August) was also warmer and wetter than normal (Table 1b). Temperatures averaged 74.9 for the season, 1.3 above the long-term average. Stations Illinois CRD 1 (northwest) CRD 2 (northeast) CRD 3 (west) CRD 4 (central) CRD 5 (east) CRD 6 (west southwest) CRD 7 (east southeast) CRD 8 (southwest) CRD 9 (southeast) Table 1b. Temperature and Precipitation for Summer (June August) 2018 Temp. ( F) Departure from longterm avg. ( ) Precip. (in) Departure from longterm avg. ( ) Illinois CRD 1 (northwest) CRD 2 (northeast) CRD 3 (west) CRD 4 (central) CRD 5 (east) CRD 6 (west southwest) CRD 7 (east southeast) CRD 8 (southwest) CRD 9 (southeast) Data from NOAA s National Centers for Environmental Information, accessed 9/10/2018. AVERAGE TEMPERATURE ( F) ACCUMULATED PRECIPITATION (IN) Aug. 1, 2018 to Aug. 31, 2018 Departure from average Aug. 1, 2018 to Aug. 31, 2018 Departure from average Figure 2a. Illinois temperature, precipitation, and their departures from average for August 2018 Source: cli-mate, Midwestern Regional Climate Center. accessed on September 1, PAGE 2

3 TOTAL MGDD FROM 4/1/2018 TO 8/31/2018 ACCUMULATED PRECIPITATION (IN) Jan. 1, 2018 to Aug. 31, 2018 Departure from average Mar. 1, 2018 to Aug. 31, 2018 Departure from average June 1, 2018 to Aug. 31, 2018 Departure from average MGDD DEPARTURE FROM 4/1/2018 TO 8/31/ Figure 2b. Illinois growing degree days and departure from average through the end of August 2018 Source: Midwestern Regional Climate Center. accessed on September 1, 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 Sept. 1, PAG E 3

4 None D0 D1 D2 D3 D4 reported seasonal highs in the 90s with lows from the 40s Current to the 60s. U.S. Drought Monitor August 28, 2018 Precipitation Last Week 68.93was higher than normal, averaging (Released Thursday, Aug , 2018) Illinois Valid inches 8 a.m. 3 Months EDT for Ago the season or 2.55 inches wetter than normal Rainfall was heaviest in the northwest and parts of southcentral Illinois where stations reported totals of 6 inches Drought Conditions (Percent Area) Calendar Year None D0 D1 D2 D3 D4 or more Water above Year 7.40normal Elizabeth in Jo Daviess County Current reported One Year Ago inches for the summer, one of the highest Last Week of the 3.83 season However, 0.00 there were also areas of dryness Intensity: Ashkum in Iroquois County received only 5.92 inches for August 28, Months Ago D0 Abnormally Dry D3 Extreme Drought the season. D1 Moderate Drought D4 Exceptional Drought (Released Thursday, Aug. 30, 2018) D2 Severe Drought The NOAA Storm Prediction Center had 40 severe Calendar Year The Drought Monitor focuses on broad-scale conditions. Valid 8 a.m. EDT weather Local conditions reports may vary. for See accompanying the month: text summary 7 for hail, 2 for tornadoes, for forecast statements. Water Year 7.40 and for 0.00 wind. 0.00(Several reports can be generated for a Author: Drought Conditions (Percent Area) One Year Ago single event.) Jessica 6.26 Blunden August 28, 2018 Drought NCEI/NOAAcontinued in western Illinois in August. In the None D0 D1 D2 D3 D4 (Released Thursday, Aug. 30, 2018) Intensity: U.S. Drought Monitor s August 28 report, 5% of the state D0 Abnormally Dry was listed D3 Extreme as in Drought Valid 8 a.m. EDT drought (Figure 4). The affected areas were Current D1 Moderate Drought D4 Exceptional Drought mainly in the west, but there were moderated drought D2 Severe Drought Drought Conditions (Percent Area) listings for parts of Kankakee and Will Counties. Twentyfour See accompanying percent text of summary Illinois was listed as abnormally dry. The Drought Monitor focuses on broad-scale conditions. Last Week None D Drought D D2 Conditions D D4 (Percent Area) Local conditions may vary for forecast statements None D0 D1 D2 D3 D4 Current Author: 3 Months Ago Jessica 0.00Blunden Last Week Current NCEI/NOAA Illinois Climate Network (ICN) Last Week JENNIE ATKINS 3 Months Calendar Ago Year The Illinois Climate Network (ICN) consists of 19 Water Year stations across the state that collect hourly weather Calendar 3 Year Months Ago U.S. Drought Monitor Illinois Water YearStart 7.40 of One Calendar Year Year Ago One Year Ago Intensity: Water Year Intensity: D0 Abnormally Dry D3 Extreme Drought D0 One Abnormally Year Ago Dry D3 Extreme 6.26 Drought D1 Moderate D1 Moderate Drought Drought D4 Exceptional Drought D4 Exceptional Drought D2 Severe Intensity: D2 Drought Severe Drought The Drought Monitor focuses on broad-scale conditions. Local conditions The Drought D0 may Abnormally vary. Monitor See accompanying focuses Dry on text broad-scale summary D3 Extreme conditions. Drought for forecast Local statements. conditions may vary. See accompanying text summary for forecast D1 Moderate statements. Drought D4 Exceptional Drought Author: D2 Severe Drought Jessica Author: The Blunden Drought Monitor focuses on broad-scale conditions. NCEI/NOAA Local conditions may vary. See accompanying text summary Jessica for forecast Blunden statements. NCEI/NOAA Figure 4. U.S. Drought Monitor report for Illinois Source: U.S. Drought Monitor. Author: Richard Heim, NCEI/NOAA. accessed on August 28, August 28, 2018 (Released Thursday, Aug. 30, 2018) Valid 8 a.m. EDT Drought Conditions (Percent Area) and soil information. ICN data for August are presented in Table 2. Wind speeds averaged 4.6 mph in August, 0.1 mph above the longterm average. The Stelle station had the month s highest average with 6.9 mph. The month s highest reported wind gust was 45.6 mph, recorded at the Dixon Springs station on August 15. Air temperatures averaged 74.9 F, 1.8 above the network s longterm average but 0.5 below the July average. Temperatures ranged from the 90s to the 50s for most stations. The month s warmest reported temperature was 96.3, which was recorded at ICN Perry on August 28. The coolest was 48.6, measured at the PAGE 4

5 DeKalb station on August 23. Soil temperatures decreased 1 to 3 on average from July but were 0.5 to 2 above the long-term averages. Temperatures at all depths decreased with the cooler weather in the third week of August, and then increased 4 to 13 the last week of the month. Temperatures under bare soil ranged from 56.4 to at 2 inch depths and 59.9 to 99.4 at 4 inches. Under sod, temperatures from 66.5 to 97.4 were reported at depths of 4 inches and 68.0 to 89.5 at 8 inches. Precipitation rose from July to 5.10 inches in August, 1.98 inches above the long-term average. Most rain fell in the second half of the month. The network averaged 4.29 inches between August 15 and 31. The majority of the network saw higher than normal rainfall with 16 of the 19 stations reporting totals above their long-term averages. Table 2. Data from the Illinois Climate Network (ICN), August 2018 Wind Air Temperature ( F) Station Avg. Speed (mph) Avg. Direction ( ) Max. Gust (mph) Max. Min. Avg. Total Solar Radiation (MJ/m 2 ) Belleville Big Bend 4.8 M M 45.4 M 9 M 50.6 M 73.7 M M Bondville 6.5 M M 29.3 M 91.3 M 50.6 M 73.2 M M Brownstown Carbondale Champaign DeKalb 5.5 M M 28.4 M 90.7 M 48.6 M 71.2 M M Dixon Springs Fairfield Freeport Monmouth Olney Peoria Perry Rend Lake Snicarte Springfield St. Charles Stelle Table 2. continued Station Average Relative Humidity (%) Total Precip. (in) Average Dew Point ( F) Total Potential Evapotranspiration (in) 4" under Sod Average Soil Temperature ( F) at 8" under Sod 2" under Bare Soil 4" under Bare Soil Belleville Big Bend 84.4 M 5.58 M 68.1 M 6 M 78.2 M 77.1 M Bondville 83.7 M 4.41 M 67.5 M 5.66 M 76.6 M 75.1 M Brownstown Carbondale Champaign M 83.8 M DeKalb 85.4 M 2.76 M 66.0 M 5.11 M 74.1 M 73.1 M Dixon Springs M 83.3 M Fairfield Freeport Monmouth Olney Peoria Perry Rend Lake Snicarte Springfield St. Charles Stelle M = Missing data. PAGE 5

6 BELLEVILLE CHAMPAIGN DeKalb's 2 in soil moisture sensor was replaced on August 22. BIG BEND DEKALB BONDVILLE DIXON SPRINGS BROWNSTOWN FAIRFIELD CARBONDALE FREEPORT Freeport's 8 in soil moisture sensor was replaced on August 1. Figure 5. August soil moisture levels at ICN stations: 2 in, 4 in, and 8 in PAGE 6

7 SNICARTE MONMOUTH OLNEY SPRINGFIELD PEORIA ST. CHARLES PERRY STELLE REND LAKE Figure 5. August soil moisture levels at ICN stations: 2 in, 4 in, and 8 in PAGE 7

8 7.0 A. IMPERIAL VALLEY The highest reported total was 8.34 inches, recorded at ICN Snicarte. The month s lowest was 1.82 inches from ICN Dixon Springs. The wetter weather caused soil moisture to increase overall at depths from 2 to 20 inches (Figure 5). The highest increases were seen in northern Illinois where levels rose an average of 79% at 2 inches. Only the east-central region did not see an increase over the month. Soil moisture remained steady at the 39 inch depths with no significant change, while moisture levels declined 5 percent, on average, at 59 inches. Other Precipitation Networks B. COOK COUNTY ERIN BAUER Imperial Valley. The average network precipitation for August 2018 was 5.98 inches, which is well above the previous 25-year network average (Figure 6a). The largest monthly gage precipitation totals were in the southwest part of Mason County. The smallest gage totals were in the northwestern edge of the network. Monthly gage totals varied 3.77 inches across the network, from 4.59 inches at site #7, east of Green Valley, to 8.50 inches at site #24, southeast of Snicarte. The year average precipitation amounts for August at Havana and Mason City are 3.76 and 3.29 inches, respectively. The August 2018 network average of 5.98 inches is 182 percent of the 25-year ( ) IVWA August network average of 3.29 inches. The Imperial Valley Water Authority funds this 20-station precipitation network operated by the Illinois State Water Survey. Cook County. During August 2018, precipitation in Cook County was near normal (Figure 6b). Gage precipitation amounts were highest in the northern half of the network area, providing well above average precipitation for the northern half of the county. The lowest monthly precipitation was measured in a band across the middle and in the southwest corner of the network. The southern half of the county received well below average network precipitation. Precipitation values ranged from 2.66 inches at site #13 (Chicago, near S. Halsted St. and W. 74th St.) to 9.36 inches at site #4 (Skokie, near Howard St. and Hamlin Ave.). The network average of 4.59 inches is about 110 percent of the 28-year ( ) August network average of 4.16 inches. The Illinois State Water Survey operates this 25-station precipitation network funded by the U.S. Army Corps of Engineers. Figure 6. Precipitation totals (inches) for (a) Imperial Valley Water Authority and (b) Cook County raingage networks August 2018 Surface Water Information BILL SAYLOR River and stream discharge and stage data are obtained from gaging stations operated by the U.S. Geological PAGE 8

9 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 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. Peak stage is represented here by morning readings posted daily by the USACE or the National Weather Service. Flood stage is defined locally for each gage location. 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. Longterm 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 August mean flow for each year of record and selecting the middle value, 50% Table 3. Peak Stages for Major Rivers during August 2018 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 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 4. Provisional Mean Flows, August 2018 Station Drainage area (sq mi) Years of record 2018 mean flow (cfs) Long-term flows Mean* (cfs) Median (cfs) Flow condition Percent chance of exceedence Days of data this month Rock River at Rockton 6, ,636 3,159 2,609 much above normal 5 31 Rock River near Joslin 9, ,349 4,831 3,968 above normal Pecatonica River at Freeport 1, , above normal Green River near Geneseo 1, normal Edwards River near New Boston normal Kankakee River at Momence 2, , normal Iroquois River near Chebanse 2, normal Fox River at Dayton 2, ,307 1, above normal Vermilion River at Pontiac normal Spoon River at Seville 1, below normal LaMoine River at Ripley 1, above normal Bear Creek near Marceline above normal Mackinaw River near Congerville below normal Salt Creek near Greenview 1, below normal Sangamon River at Monticello normal South Fork Sangamon near Rochester above normal Illinois River at Valley City 26, ,298 13,880 11,802 below normal Macoupin Creek near Kane above normal Vermilion River near Danville 1, normal Kaskaskia River at Vandalia 1, normal Shoal Creek near Breese above normal Embarras River at Ste. Marie 1, above normal Skillet Fork at Wayne City above normal Little Wabash below Clay City 1, above 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). *As reported in U.S. Geological Survey (USGS) Water Resources Data, Illinois, Water Year 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. PAGE 9

10 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 aggregated statewide, using the available monthly mean data shown this month in Table 4, was above the median value for August (approximately 170% of the median) and about equal to the mean for August (approximately 98% of the mean). Monthly mean discharge values primarily ranged from normal to above normal for August, with considerable variation reflecting localized precipitation. Monthly mean flow was below normal for August at some central Illinois streamgage stations, including the Illinois River at Valley City. 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 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-july water levels at 25 reservoirs Table 5. Reservoir Levels in Illinois, August 2018 Reservoir County Normal pool or target level (feet) Current level difference from normal or target (feet) Monthly change (feet) Average difference from normal or target (feet) Years of record July reported pumpage (million gallons) Altamont Effingham Bloomington McLean N/A Carlinville Macoupin Carlyle (1) Clinton N/A Decatur (1,3) Macon ,095.5 Evergreen (4) Woodford N/A Glenn Shoals (2) Montgomery N/A N/A w/hillsboro Highland Madison Hillsboro (2) Montgomery N/A 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 no meter Mt. Olive (new) Macoupin N/A N/A 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 N/A 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 September 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. PAGE 10

11 Table 6. Month-End Shallow Groundwater Level Data Sites, August 2018 No. 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 50 NA NA NA NA NA 3 Crystal Lake McHenry Fermi Lab DuPage Good Hope McDonough Snicarte Mason Coffman Pike Greenfield Greene Janesville Coles St. Peter Fayette 10 NA NA NA NA NA 11 SWS #2 St. Clair Boyleston Wayne NA NA NA NA NA 13 Sparta Randolph SE College Saline Bondville Champaign Averages Notes: N/A = Data not available. for which levels were reported last month and this month, reported end-of-august water levels were lower at 15 reservoirs, higher at 7 reservoirs, and about the same as at the end of last month at 3 reservoirs. For the 26 reservoirs with measurements reported at the end of August, water levels were below normal target pool or spillway level at 14 reservoirs, above normal target pool or spillway level at 5 reservoirs, and at about full pool level at 7 reservoirs. Major Reservoirs. Compared to water levels at the end of July, at the end of August the water level at Lake Shelbyville was 0.8 feet lower, Carlyle Lake was 0.3 feet higher, and Rend Lake was 0.3 feet lower. At the end of August, Lake Shelbyville was 0.3 feet above the summer target level, Carlyle Lake was 0.8 feet above the summer target level, and Rend Lake was 0.9 feet above the spillway level. Great Lakes. Current month mean and end-of-month values are provisional and are relative to International Great Lakes Datum The August 2018 mean level for Lake Michigan was feet. The monthly mean level one year ago (August 2017) was feet. The long-term average lake level for August is feet, based on data. In this period of record, the lowest mean level for Lake Michigan for August occurred in 1964 at feet, and the highest level for August 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 12 observation wells, which are remote from pumping centers, were above normal for the month of August. Levels averaged 0.7 feet above and ranged from 3.9 feet below to 4.3 feet above normal levels (Table 6). Comparison to Previous Month. Shallow groundwater levels were just below those of the previous month. Levels averaged 0.1 foot below and ranged from 1.6 feet below to 1.3 feet above levels of July. Comparison to Same Month, Previous Year. Shallow groundwater levels in August were above levels measured one year ago. Levels averaged 0.5 feet above this month and ranged from 5.4 feet below to 5.4 feet above levels of August Data sources for 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 Griffith Drive Champaign, IL (217)