State Water Survey Research Articles

Giant raindrops seen in warm clouds

A paper in this month's issue of Geophysical Research Letters helps to dispel the conventional idea that raindrops 4–8 mm in diameter can only result from the melting of cloud ice. Giant raindrops up to 8 mm in diameter have now been observed in tropical rainstorms, according to Kenneth V. Beard of the Illinois State Water Survey (Champaign, Ill.), David B. Johnson of the Division of Atmospheric Resources Research in the Bureau of Reclamation (Denver, Colo.), and D. Baumgardner of the National Center for Atmospheric Research (Boulder, Colo.). The clouds studied in the Hawaiian Warm Rain Project were limited by a marine inversion to altitudes where the temperature is above the freezing point.

A field intercomparison of methods for the measurement of particle and gas dry deposition

Concurrent measurements of the dry deposition of sulfate, particulate sulfur, nitrate, sulfur dioxide, ozone, and nitric acid were made during September 1981 and June 1982, using several independent methods. The measurements were conducted at a common site, which was a grasscovered 32‐ha field in a topographically flat, rural area 14 km southwest of Champaign, Illinois. Research groups from 14 U.S. and Canadian institutions participated in the study, which was coordinated by the Illinois State Water Survey. Micrometeorological methods such as eddy correlation, variance, concentration gradient/modified Bowen ratio calculation, and eddy accumulation were used. Deposition collection methods such as surrogate surface sampling and vegetation washing were also employed. Sampling schedules and heights of measurements were arranged to maximize the comparability of results from the various flux determination techniques. Sulfate and particulate sulfur mean deposition velocities, vd, on the order of 0.3 cm/s were found by several methods. Nighttime values were small, generally near zero, while daytime vd of up to 1.0 cm/s were observed. A possibly significant contribution to the total sulfur flux by large (diameter >2.0 μm) particle associated sulfate was noted in some periods. Daytime sulfur dioxide and nitric acid vd of greater than 3.0 cm/s were measured, suggesting near‐zero vegetation canopy resistance to mass transfer for these gases.

Rates of Dry Deposition Determined Using Wet/Dry Collectors

Daily samples of dryfall were collected during the June 1982 Dry Deposition Measurement Intercomparison Study at Champaign, Illinois, using six Aerochem Metrics wet/dry collectors. Upon completion of the field experiment, these samples were analyzed at the Environmental Measurements Laboratory for pH and for their concentrations of major inorganic constituents. Contamination by rain and bird droppings rendered a number of dryfall samples unusuable. When data for these samples were removed, the remaining data displayed acceptable precision for sulfate, calcium, and magnesium. The measured deposition rates varied between 7 and 73 ng/m2/s for sulfate, between 7 and 44 for calcium, and between 0.8 and 8.1 for magnesium. The precision of the data for ammonium, nitrate, and phosphate was poor, so we have not calculated deposition rates for these constituents. The measurements of the atmospheric concentrations of sulfate reported by the Illinois State Water Survey have been used to calculate deposition velocities for particulate sulfate for 18 daily samples, even though the aerosol sampler and the dry bucket of the wet/dry collector may not sample the same size population of particulates. These velocities ranged from 0.1 to 1.2 cm/s, with a median value of 0.4 cm/s and a mean of 0.45±0.31 cm/s.

Thunder day increase

A report issued by the Illinois State Water Survey concludes that annual values of thunder days for North America exhibited a general increase of about 15% from 1901 to 1945, followed by a general decrease of 10% from 1945 to 1980. A study of the variability of thunder days across North America showed a general decrease with time, particularly after 1940. A major finding of this study is that frequencies of thunderstorms over areas as large as the North American continent show major long‐term trends.The report, “Temporal Distribution of Global Thunder Days,” summarizes the results of a 1‐year study by Stanley A. Changnon, Jr., and Chin‐Fei Hsu of the temporal variations of thunder‐day records during 1901–1980 using quality weather records from weather stations scattered around the globe. A thunder day is recorded when one or more peals of thunder are heard anytime during the 24‐hour period from midnight to midnight, which is consistent with the definition of a thunderstorm used at first‐order weather stations since 1897. They found most stations in the northern hemisphere north of 45° latitude exhibited a general increase in thunder activity from 1901 to 1980. The project was funded by the National Science Foundation.

New climate delivery system developed

The Illinois Climate Center can now provide information through the Climate Assistance Service (CLASS) about the current status of many weather parameters, such as accumulated degree days, differences between seasonal rainfall and normal, and long‐range future climate predictions. Illinois is the first state to start such a near real‐time climate information system where the observations are gathered from National Weather Service cooperative observers.The concept of CLASS was envisioned and designed by Stanley Changnon, chief of the Illinois State Water Survey; Wayne Wendland, head of the Climatology and Meteorology Section; and John Vogel, head of the survey's Climate Information Unit. Grants from the Illinois Department of Energy and Natural Resources and from the National Oceanic and Atmospheric Administration (Climate Analysis Center and National Climate Program Office) were coupled with existing Survey funds and information products of the Illinois State National History Survey to develop this system.

Effectiveness of street sweeping in urban runoff pollution control

In March 1982, the Illinois State Water Survey completed a three-year study for the Illinois Environmental Protection Agency to determine the effects of municipal street sweeping on urban storm runoff quality. The project was part of the Nationwide Urban Runoff Program sponsored by the U.S. Environmental Protection Agency. In Champaign, Illinois, four urban drainage basins featuring separate sewers and ranging in size from 16 to 55 acres (6.5−22.3 ha) were instrumented for runoff event monitoring and sampling. Data collection included recording of precipitation and storm runoff and sampling of runoff and atmospheric fallout. A telemetry system was developed and installed to link the remote sampling sites to a minicomputer which automatically controlled the collection and storage of data and the instruction for sampling. During 1980 and 1981, samples were collected and analyzed for total concentrations of solids, metals, and nutrients for 90 events. A street dirt sampling program designed to measure the total loads of material on the streets was conducted over the same period. Determinations were made of the particle size distributions and constituent concentrations in the street loads. Municipal street sweeping at different frequencies was practiced on the basins during the monitoring period. The procedures used in data collection and the results obtained from the sampling programs are presented and discussed. For the conditions monitored, street sweeping is shown to be ineffective as a management practice for urban storm runoff quality control.

Out-of-Level Instruments: Errors in Hydrometeor Spectra and Precipitation Measurements

Abstract Meteorological instruments which are designed to measure the size spectra of hydrometeors such as hailstones or raindrops or instruments designed to measure cumulative precipitation such as raingages can produce errors if they are not installed and maintained with their sensing surfaces level. Errors from this source have generally been assumed to be negligible or ignored completely in most studies of rainfall and hailfall apparently because levelness is often taken for granted. This paper examines the effects on spectra and integrated precipitation measurements when the wind is blowing and the measuring instrument is out of level. Examples of out-of-level instruments are given based on National Hail Research Experiment hailpad data, data from the Illinois State Water Survey raindrop camera, and government-operated and volunteer-observer raingages. Raingages, for example, that are out of level by 2° in the presence of winds of 10 m s−1 can produce errors on the order of 9%.

Regional climate coordinating office

In September 1981, the National Climate Program Office (NCPO) funded the Regional Climate Coordinating Office (RCCO) at the Illinois State Water Survey and the Illinois Agricultural Experiment Station, both located at the University of Illinois. This is the first year of a proposed 4‐year project developed under the aegis of the North Central Regional Research Committee, NC‐94, sponsored by the agricultural experiment stations of the U.S. Department o f Agriculture. The NC‐94 Committee, devoted to the characterization and assessment of climate on agriculture and other renewable resources, devised a plan to demonstrate the feasibility of coordinating state climate services in the 12‐state north central region. The 12 states are Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri, Nebraska, North Dakota, Ohio, South Dakota, and Wisconsin. A key component of the initial structure of the plan is the RCCO.

First Comparisons of Rainfall Rates Derived from Radar Differential Reflectivity And Disdrometer Measurements

A comparison between radar-derived rainfall rates and those obtained from a ground-based disdrometer located at the radar site is presented. The radar measurements were made in the vicinity of Chicago, IL, on August 2, 1978, with the CHILL radar of the Illinois State Water Survey. Three radar-derived profiles of rainfall rate versus distance from the radar were obtained for a single storm in the direction of the storm path toward the radar. These profiles indicated the storm motion and the variability of rainfall as the storm progressed toward the radar. The last two profiles support the hypothesis that the storm was in steady state as it passed over the radar site. This provided an opportunity to compare the radar-derived rates with an apparent rate versus distance profile derived from a disdrometer time record of rainfall rate obtained at the radar site. Excellent agreement between the radar and disdrometer measurements of rainfall resulted.

Illinois Water Survey

Flooding is a major problem that plagues the nation. The flooding problem encompasses a wide spectrum of physical and social scientific issues that need resolution. Scientists at the Illinois State Water Survey were recently awarded a grant of $106,600 by the National Science Foundation to prepare a comprehensive national plan of research on floods and their mitigation. The Illinois State Water Survey has a history of research on floods and flooding. It serves as the repository for all floodplain information in Illinois.

An Approach to Crop-Hail Insurance Rate Revision

Hailstorms are meteorological events that have a considerably adverse impact on crop production. Variation of these events in time and space, in turn, influence crop-hail insurance rate structure. Crop-hail insurance companies normally review their rate schedules every 3–5 years. The Illinois State Water Survey, in cooperation with the Crop-Hail Insurance Actuarial Association, has done research applicable to providing guidelines for adjusting state insurance rates up or down, or for keeping them the same for the next few years. The research was designed to develop and test methods of predicting trends in future hail loss cost for various crops grown in the principal hail loss districts across the United States. Time series analysis procedures were performed on the hail loss variable. Results indicated an accuracy of 80% and were sufficiently encouraging to recommend incorporation in the rate-making process.

User Oriented Climatic Information for Planning a Snow Removal Budget

Abstract Many activities associated with the transportation sector are weather sensitive. This study is concerned with highway maintenance activities, specifically snow removal, and the budgeting of same by the Illinois Department of Transportation (IDOT). During the 1978–79 winter, IDOT's snow removal budget was exhausted by the end of January, thereby necessitating the procurement of emergency funds. The following year, the Illinois State Water Survey (ISWS) was asked to provide specialized climatic design information that could be used to assist IDOT in its budget planning for snow removal. Snow removal is often accomplished by spreading road salt over snow- and ice-covered roads, thus improving traction and reducing the risk of vehicles skidding along slippery surfaces. This study demonstrates the computation of “salt days,” a user-oriented climatic variable that indicates the number of days when road salt is required. This variable is defined using certain temperature and snowfall criteria. Results o...

A Preliminary Study of Comparative Measurements of Rainfall Rate Using the Differential Reflectivity Radar Technique and a Raingage Network

Abstract Radar measurements of average rainfall rate over two separate 550 km2 areas am compared with raingage measurements in the same areas over time intervals of ∼1 h. The measurements were performed to test the differential reflectivity (ZDR) technique of Soliga and Bringi (1976) which provides a means of estimating rainfall rate (R)by combining measurements of radar reflectivity factors at horizontal (ZH) and vertical (ZV) polarizations; ZDR(dB) is defined as the ratio of these reflectivities, i.e., ZDR = 10 log(ZH/ZV). Results from an experiment performed near Chicago, Illinois, on 9 August 1978, using the University of Chicagco-Illinois State Water Survey (CHILL) radar and the Illinois State Water Survey's Chicago Hydrometeorological Area Project (CHAP) raingage network are presented. ZDR estimates of rainfall rate compared very favorably with the raingages measurements and were significantly better than estimates obtained from two Z-R relationships, one of which was obtained by raingage calibratio...

1980 Midwest Meeting

The sixth annual Midwest AGU Meeting was held at Holmes Center, Northern Illinois University, DeKalb, Illinois, on September 18 and 19,1980. Over 200 registrants presented 95 papers in 12 sessions: Isotope Studies of Hydrologic Processes, chaired by E. C. Perry, Jr., and C. W. Montgomery, Northern Illinois University; Petrology and Geochemistry, chaired by J. Berg, Northern Illinois University; Late Precambrian Magmatism, chaired by J . Berg and M. G. Mudrey, Jr., Wisconsin Geological and Natural History Survey; Midwest Coal Hydrology, D. E. Lindorff, Illinois State Geological Survey, and T. Naymik, Illinois State Water Survey; Hydrology, D. E. Lindorff; General Geophysics, C. P. Ervin, Northern Illinois University; Tectonics of the Transantarctic Mountains, P. N. Webb, Northern Illinois University; Northern Illinois Deep Drill Hole, B. Haimson, University of Wisconsin, and W. J. Hinze, Purdue University; Rift Tectonics in the Mississippi Embayment, T. C. Buschbach, Saint Louis University; Geology and Tectonics of the Pre‐Mt. Simon Clastics in the Midcontinent, W. J. Hinze and E. G. Lidiak, University of Pittsburgh; Paleozoic Paleomagnetism of the Midcontinent, V. A. Schmidt, University of Pittsburgh; Midcontinent Seismology, O. W. Nuttli, Saint Louis University.The general session was opened with a welcoming address by James D. Norris, dean of the College of Liberal Arts and Sciences. Jack Simon, chief of the Illinois State Geological Survey, described the role of the Survey during its first 75 years and went on to discuss its future responsibilities in an after dinner speech on Thursday evening.

The Robert E. Horton medal: Citation and acceptance

When William C. Ackermann retired as chief of the Illinois State Water Survey last November to become adjunct professor of civil engineering, he had devoted 44 years to hydrology. During that time he had achieved national and international recognition for his expertise and outstanding leadership in research, planning, and management of water resources. Now he is sharing his rich storehouse of knowledge with students at the University of Illinois.In a field that has produced many giants, Bill Ackermann's achievements stand apart because of his wide diversity of interests. Equipped with his engineering degree from the University of Wisconsin, he spent 19 years in the Water Control Planning Department of the Tennessee Valley Authority, where he was concerned with water resources research, planning, and operations. This was followed by 2 years as head of the Watershed Hydrology Section of the Agricultural Research Service of the United States Department of Agriculture. During this period, he was responsible for a nationwide program of research in soil and water.

Algae Concentration Analysis by Computer

Since 1945 the Illinois State Water Survey, in cooperation with the Champaign District Office of the U. S. Geological Survey, has maintained a program designed to assess the mineral quality of selected surface waters in Illinois. The results of this continuing program have been reported in Water Survey Bulletins 45, 54, and 56.A new dimension was added to the program in October 1971. Samples were collected at monthly intervals from the waters of 35 streams at 41 locations and were examined for algal density and type as well as mineral quality. Besides the stream sampling program for special studies, algae data has been collected from over 100 other sites throughout the State of Illinois' lakes, impoundments, strip mine pits, and small creeks. The biologist must look into the microscope and identify the algae, but this new procedure with the aid of the computer reduces the time between the identification stage and the publishing of the results.The methodology of collecting the samples, identifying the algae, coding the data, and processing the information is described. The analysis step has been standardized so results are uniformly reported from one study to the next. The data is coded systematically so a compatible data base can be maintained and augmented as more data is collected. The system was designed to eliminate repetitive steps and to be open ended in nature. The overall goal of the system or procedure was to eliminate errors, and shorten the time period between data collection and reporting of the results.

Assessing Public Ground‐Water Supplies in Illinois

ABSTRACTIllinois aquifers furnish approximately 233 mgd (10.2 m3/s) of water to 677 public‐water supplies outside the six‐county area of northeastern Illinois. Ground water is usually obtained from sand‐and‐gravel deposits in the glacial drift or from limestone or sandstone formations in the underlying bedrock. The most favorable ground‐water conditions are found in the northern third and the southern tip of the State, while, elsewhere, major aquifers are sand‐and‐gravel deposits of the Mississippi, Illinois, buried Mahomet, Wabash, Ohio, Kaskaskia, and Embarrass valleys.A brief review was made of data and information in the State Water Survey files for each public ground‐water supply, and an assessment was given as adequate, marginal, or deficient, in terms of present demands. Twenty‐four supplies were studied in greater detail, including calculations of aquifer sustained yields. The study indicated that 39 supplies were marginal and four were judged deficient in meeting current demands. The majority of the marginal and deficient supplies are located in the central third of the State; but so are most of the supplies (outside of north‐eastern Illinois).The study represents the first of a three‐part plan to: (1) define problem areas and determine priorities for studies in greater detail, (2) conduct regional studies, including test drilling, in problem areas to determine how great the water resource is, and (3) determine the water resource alternatives available to public ground‐water supplies that are found to be inadequate.

Differential Reflectivity Measurements in Rain: First Experiments

Results of the first measurements of differential reflectivity (ZDR) in rain are reported. ZDR = 10 log (ZH/ZV) dB involves copolar measurements of ZH and ZV, the radar reflectivity factors at horizontal and vertical polarizations, respectively. The data were obtained with the University of Chicago-Illinois State Water Survey (CHILL) radar facility in Oklahoma during Spring 1977 and confirmed theoretical expectations that ZDR should be positive, ranging between around 0-4 dB. By combining ZDR measurements with ZH, it is shown how estimates of N0 and D0, the parameters of an exponential raindrop size distribution, can be obtained. These estimates were subsequently used to compute rainfall rates as a function of range along a radar ray. These results illustrate that ZDR can have important applications in the quantitative, remote measurement of drop-size distributions and rainfall.

Central Illinois Weather and Rainfall Study

Central Illinois will be a laboratory this summer for four major studies of weather and rainfall.Stanley A. Changnon, Jr., of the Illinois State Water Survey at the University of Illinois said that facilities of the survey and university are bringing together scientists from New York, Virginia, Florida, Wisconsin, Illinois, Colorado, Washington, and California. The scientists will study what happens when winds converge over the flatlands of Illinois.

Hail bibliography developed

An on‐line hail bibliography, developed under the direction of Stanley A. Changnon, Jr., is available through the Illinois State Water Survey. Coverage of the topic of hail is comprehensive. The literature surveyed is primarily from 1950 to date, with some items of historical interest also included. Coverage of the literature is worldwide, with primary emphasis on English‐language publications.