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121:		Title:	Ground-water recharge and runoff in Illinois
		Volume/Number:	1965
		Issuing Agency:
		Description:	Recharge conditions in several areas of northeastern Illinois are described, and recharge rates for several aquifers in central and southern Illinois are given. Recharge rates to deeply buried bedrock and sand-and-gravel aquifers vary from 1300 to 500,000 gallons per day per square mile (gpd/sq mi). The lowest rate is for an area where the Cambrian-Ordovician Aquifer is overlain by the Maquoketa Formation consisting mostly of shale; the highest rate is for an area where a sand-and-gravel aquifer is overlain by permeable coarse-grained deposits. Groundwater recharge generally is at a maximum during wet spring months; in many years there is little recharge during the five-month period July through November. The theoretical aspects of recharge from precipitation are discussed; recharge rates vary with the coefficient of vertical permeability, the vertical head loss associated with recharge, and the saturated thickness of deposits through which vertical leakage of water occurs. Recharge rates are not constant but vary in space and time. A summary of coefficients of vertical permeability and leakage of deposits overlying aquifers within the state is presented. Coefficients of vertical permeability of glacial deposits range from 1.60 to 0.01 gallons per day per square foot (gpd/sq ft). The average coefficient of vertical permeability of the Maquoketa Formation is 0.00005 gpd/sq ft. Coefficients of leakage of glacial deposits and bedrock confining beds range from 2.3 x 10-1 to 2.5 x 10-7. Annual ground-water runoff from 109 drainage basins scattered throughout Illinois is estimated with streamflow hydrograph separation methods and flow-duration curves. The relations between groundwater runoffs during years of near, below, and above normal precipitation and basin characteristics such as geologic environment, topography, and land use were determined by statistical analysis. Groundwater runoff is greatest from glaciated and unglaciated basins having considerable surface sand and gravel and underlain by permeable bedrock. Groundwater runoff is least from glaciated basins with surface lakebed sediments and underlain by impermeable bedrock. Groundwater runoff during a year of near normal precipitation ranges from 0.06 to 0.43 cubic feet per second per square mile (cfs/sq mi). Groundwater runoff is at a maximum during spring and early summer months, and is least in late summer and fall months. Annual groundwater runoff depends upon antecedent moisture conditions as well as the amount and distribution of annual precipitation. Because many aquifers in Illinois are deeply buried, not all groundwater runoff can be diverted into cones of depression because there is some lateral as well as vertical movement of water in surface deposits. Data on groundwater runoff can be useful in estimating recharge to aquifers and in evaluating the potential yield of groundwater reservoirs. However, studies indicate that no simple relation exists between groundwater runoff and the potential or practical sustained yields of aquifers.
		Date Created:	9 24 2004
		Agency ID:	RI-48
		ISL ID:	000000000930 Original UID: 999999993912 FIRST WORD: Ground

122:		Title:	Groundwater resources of the buried Mahomet Bedrock Valley
		Volume/Number:	1969
		Issuing Agency:
		Description:	The buried Mahomet Bedrock Valley and its major tributaries cover an area of about 3700 square miles in east-central Illinois. Large supplies of groundwater chiefly for municipal use are withdrawn from wells in permeable sands and gravels in thick deposits of glacial drift in the area. The glacial drift exceeds 400 feet in thickness in places. The largest source of groundwater consists of the sands and gravels of the Kansan deposits, called the deep aquifer, which occupy the deepest portions of the Mahomet Valley channel. Intercalated in the glacial drift above the Kansan deposits are sands and gravels of the Illinoian deposits, called the middle aquifer. The middle aquifer is a secondary source of groundwater. The coefficients of permeability and storage for the middle aquifer range from 230 to 4080 gallons per day per square foot (gpd/sq ft) and from 0.00001 to 0.083, respectively. They range from 310 to 4100 gpd/sq ft and from 0.000022 to 0.0023, respectively, for the deep aquifer. The coefficients of the vertical permeability of the confining beds above the middle and deep aquifers range from 0.0026 to 0.04 gpd/sq ft and 0.005 to 0.42 gpd/sq ft, respectively. Pumpage from wells increased from 8.5 million gallons per day (mgd) in 1890 to 46.3 mgd in 1960 and was 40.2 mgd in 1965. Of the 1965 total pumpage, 64.2 percent was for municipal supplies, 19.1 percent was for rural uses, and 16.7 percent was for industrial use. Wells in the deep aquifer accounted for 49.3 percent of the 1965 total; wells in the middle aquifer, 31.8 percent; wells in shallow unconsolidated deposits, 17.4 percent; and wells in bedrock aquifers, 1.5 percent. Major pumping centers with pumpage exceeding 1 mgd are located at Champaign-Urbana, Rantoul, Lincoln, Taylorville, and Hoopeston. As a result of heavy pumpage, water levels in the middle aquifer at Champaign-Urbana declined as much as 100 feet between 1885 and 1947. Subsequent shifting of pumpage to the deep aquifer west of Champaign resulted in water levels in the middle aquifer recovering from 30 to 55 feet. Because of increased withdrawals, water levels in the deep aquifer declined some 35 feet during 1948- 1963. Recovery of water levels in 1964 and 1965 resulted from a decline in pumpage. Similar though smaller water-level declines have occurred in many of the other pumping centers in the Mahomet Valley area. Recharge to buried aquifers in the Mahomet Valley occurs chiefly as leakage of water from a source bed in the shallow deposits across a confining layer. Potential recharge to these aquifers, considering only available head losses across the confining layers, is great. Computations for the Illinoian aquifer at Champaign-Urbana indicate a recharge rate of 115,000 gpd/sq mi in 1947. Similar computations for the Kansan aquifer west of Champaign during the period 1953 through 1965 indicated an average recharge rate of 107,000 gpd/sq mi. Total groundwater runoff for the valley is estimated to be about 740 mgd during years of normal precipitation. It is not unreasonable to assume that existing and/or future pumping centers could capture 60 percent of groundwater runoff, or 445 mgd. An electric analog computer consisting of an analog model and associated electronic equipment was constructed for the middle and deep aquifers and their confining and source beds in the vicinity of Champaign-Urbana to aid in studying the effects of groundwater pumpage on water levels in the Mahomet Valley. The accuracy of the computer was established by a study of records of past pumpage and water levels in three observation wells. The analog computer was used to determine pumping levels with a selected scheme of pumping from existing and future large capacity wells in the Kansan aquifer west of Champaign. Withdrawals with the selected pumping scheme would total 30.3 mgd from existing large capacity wells and 15 mgd from five future wells; pumping levels would be above the top of the Kansan aquifer.
		Date Created:	5 18 2005
		Agency ID:	RI-62
		ISL ID:	000000000931 Original UID: 999999993927 FIRST WORD: Groundwater

123:		Title:	Water resources availability, quality, and cost in northeastern Illinois
		Volume/Number:	1976
		Issuing Agency:
		Description:	This report summarizes extensive studies of the water resources of northeastern Illinois. This 3700-hundred square mile metropolitan-industrial area includes Cook, DuPage, Kane, McHenry, Lake and Will Counties with a population of seven million persons.Water shortages, depending on resource use schemes, may approach 200 million gallons by the year 2000. Possibilities for meeting these needs are described as a guide to allocation of Lake Michigan water and future planning for water resources.
		Date Created:	9 24 2004
		Agency ID:	RI-83
		ISL ID:	000000000932 Original UID: 999999993945 FIRST WORD: Water

124:		Title:	Hydraulics of flow in the Kaskaskia River, Illinois
		Volume/Number:	1979
		Issuing Agency:
		Description:	The hydraulics of flow was investigated at two reaches in the Kaskaskia River. The discharge varied from 58 to 4000 cubic feet per second and the flow frequency varied from 5 to 88 percent. The head loss varied from 0.96 feet/ mile for high flows to 1.98 feet/mile for low flows. The vertical velocity distribution was found to follow a logarithmic distribution. A theoretical distribution predicted the lateral velocity distribution in the bends reasonably well. In all, 79 isovels were developed for all flow conditions. The average value of the energy coefficient was 1.45 for straight reaches and 1.43 for bends. Similarly, the average value of the momentum coefficient was 1.22 for straight reaches and 1.18 for bends. Manning's roughness coefficient varied from 0.039 to 0.053. During low flows, the river flows through a series of pools and riffles. The median diameter of bed materials varied from 40 millimeters in the riffle to 0.04 millimeters in the pool, whereas the Froude number changed from 0.7 to 0.01. During high flows, the effect of the pool and riffle on the flow condition is minimal or nonexistent.
		Date Created:	9 24 2004
		Agency ID:	RI-91
		ISL ID:	000000000933 Original UID: 999999993954 FIRST WORD: Hydraulics

125:		Title:	The 1980-1981 drought in Illinois: causes, dimensions, and impacts
		Volume/Number:	1982
		Issuing Agency:
		Description:	This report addresses the 1980-1981 drought in Illinois. This 15-month drought, which began in February 1980 and was centered in the southern portions of the state, was not one of the extreme droughts of record. However, its importance derives from the fact that it is the most severe drought since those of the early 1950s. As such, the 1980-1981 drought potentially reflects a new set (or new types) of impacts on the states water resources due to many technological, hydrological, and institutional changes since the 1950s.As noted above, droughts are a basic and important feature of the climate and water resources of Illinois. The interesting near absence of droughts in the state between 1955 and 1976 makes the drought of 1980-1981 of great interest, although it was not extremely severe.
		Date Created:	9 25 2004
		Agency ID:	RI-102
		ISL ID:	000000000934 Original UID: 999999993965 FIRST WORD: The

126:		Title:	Hydrology, hydraulics, and sediment transport, Kankakee and Iroquois Rivers
		Volume/Number:	1983
		Issuing Agency:
		Description:
		Date Created:	9 24 2004
		Agency ID:	RI-103
		ISL ID:	000000000935 Original UID: 999999993966 FIRST WORD: Hydrology,

127:		Title:	Impacts of irrigation and drought on Illinois ground-water resources
		Volume/Number:	1987
		Issuing Agency:
		Description:	This investigation is the first of three phases of a ground-water management study. In this report, effects of irrigation and drought on the ground-water resources of Illinois are examined. Irrigation water use for five soil types is estimated from a monthly water budget model on the basis of precipitation and temperature data from the last 30 years at selected weather stations across Illinois. Moisture deficits are computed for each soil type on the basis of the water requirements of a corn crop. It is assumed that irrigation is used to make up the moisture deficit in those places where irrigation systems already exist. Irrigation water use from each township with irrigated acreage is added to municipal and industrial ground-water use data and then compared to aquifer potential yields. The spatial analysis is accomplished with a statewide geographic information system. An important distinction is made between the seasonal effects of irrigation water use and the annual or long-term effects. The model is tested for its sensitivity to weather variation; seasonal water deficits are calculated by using data from extreme growing seasons and extended drought periods. The effect of increasing the amount of irrigated land by 50 percent is also considered for normal weather conditions and droughts. The effect of variable irrigation demand on ground-water resources is expressed as the ratio of ground-water use to ground-water potential yield for each township. This is done to highlight regions most susceptible to ground-water stress because of drought or increased irrigation by showing where use could exceed yield. The sensitivity of the results is not tested for variations in spatial aggregation. This will be one of the primary tasks in subsequent study phases. Results show that irrigation is a substantial seasonal consumptive ground-water use in Illinois, with the potential for growth. However, present effects appear to be localized and highly dependent on weather conditions. Some potential for seasonal or temporary overpumpage may exist in the heavily irrigated areas during years with below-normal precipitation or during extended droughts. The aquifers being used for irrigation appear to have the ability to recover from present irrigation demands without suffering significant depletion, implying that the annual effect of irrigation is currently relatively minimal. The exception to this may be during extended drought periods, especially if widespread expansion of irrigation practices also occurs in the state. A 50 percent expansion of irrigation would appear to have surprisingly little additional impact on ground-water resources under most climatic conditions. That degree of growth around currently irrigated land would result in expanded irrigation areas still within reach of the productive, high-yielding aquifers already being pumped for irrigation. A much larger degree of irrigation expansion into areas with heavier-textured soils is possible in Illinois. The availability of ground-water would be a major limiting factor in the speed and direction of that expansion. That kind of massive irrigation expansion is not considered in this report; however, its effects on the state's ground water are assumed to be considerable and will be addressed in subsequent study phases. The Chicago metropolitan area stands out as a major region of overpumpage, but not because of irrigation. Variable irrigation pumpage does appear to consistently affect several other regions, most notably parts of Mason, Kankakee, Tazewell, Lee and Whiteside Counties. The degree to which these counties are affected by irrigation depends largely on weather conditions. For all these counties, with the possible exception of Kankakee, surficial sand and gravel aquifers are the most susceptible to stress from drought and irrigation water use. Shallow bedrock aquifers may also be impacted by irrigation in parts of Kankakee County. The impact of an extended drought is likely to be more widespread and inconsistent because of the multiple effects of increased water use for irrigation and other demands, and reduced ground-water storage.
		Date Created:	9 24 2004
		Agency ID:	RI-109
		ISL ID:	000000000936 Original UID: 999999993972 FIRST WORD: Impacts

128:		Title:	Ground-water quantity laws and management
		Volume/Number:	1991
		Issuing Agency:
		Description:	In the last decade, Illinois has seen many changed attitudes and laws governing the use and withdrawal of ground water. Almost certainly, the next decade will see continued change as the legal structure is adapted to increasing demand for ground water and to the resultant and growing pressures on our ground-water resources. This report summarizes groundwater quantity laws and management programs in Illinois and a number of other states. It compares the present system in Illinois with those in other states and lists recommendations for improvements in Illinois laws.
		Date Created:	9 24 2004
		Agency ID:	RI-114
		ISL ID:	000000000937 Original UID: 999999993977 FIRST WORD: Ground

129:		Title:	Irrigation practices in Illinois
		Volume/Number:	1991
		Issuing Agency:
		Description:	Biweekly and total irrigation amounts and irrigation scheduling practices were monitored at representative sites in central Illinois during the 1988 and 1989 growing seasons. The purpose was to gather baseline information on average quantities of irrigation water used in normal and drought years and on the general efficiency of irrigation operations in the subhumid climate of Illinois. Soil water-holding capacity is the most important factor in determining irrigation amounts, explaining about 65 percent of the variability in irrigation totals. Other important factors in explaining irrigation variations include weather changes, individual farmer idiosyncrasies, and crop differences. In general, irrigation farmers in Illinois appear to be applying appropriate amounts of irrigation water at appropriate times in the growing season, based on their soil type, crop type, and total evaporative losses.
		Date Created:	9 24 2004
		Agency ID:	RR-118
		ISL ID:	000000000938 Original UID: 999999993981 FIRST WORD: Irrigation

130:		Title:	The 1988-1989 drought in Illinois: causes, dimensions, and impacts
		Volume/Number:	1992
		Issuing Agency:
		Description:	The 1988-1989 drought was one of the most disastrous droughts in the history of the state. Hydrologic, meteorological, and climatological aspects of the 1988-1989 drought in Illinois are addressed. The drought is evaluated in terms of recipitation, streamflow, lakes and reservoirs, and ground-water resources of the state. The meteorological conditions that produced the drought also are addressed. Impacts and problems resulting from the drought are discussed along with various actions taken to ameliorate the problems. Although the primary goal of the study was to quantify the drought, primarily in a physical sense, an important secondary goal was to assess the impacts and the actions employed in order to derive information needed in future planning and handling of Illinois droughts. The report thus ends with a set of recommendations for coping with future droughts.
		Date Created:	9 28 2005
		Agency ID:	RR-121
		ISL ID:	000000000939 Original UID: 999999993984 FIRST WORD: The

131:		Title:	Overview of recommended Phase III water quality monitoring: Fox River investigation.
		Volume/Number:	2005
		Issuing Agency:
		Description:	This water quality monitoring plan describes the monitoring recommended to provide data needed to improve calibration of the watershed loading (HSPF) and receiving stream (QUAL2) models for the Fox River watershed. Various monitoring schemes were considered in light of available resources. Data gaps identified in the Phase I report as well as preliminary model simulations also were considered in preparing this monitoring plan. Because available resources are a limiting factor, closing data gaps is the primary objective of the proposed monitoring plan. Should additional funds become available, specific additional data collection scenarios would enhance the reliability of the models. These recommendations are written to be incorporated by the Fox River Study Group, Inc. (FRSG) into the request for proposals (RFP) to conduct the monitoring. The proposed monitoring requires installation and operation of the following: (1) 9 hourly precipitation stations, (2) 11 stream flow gages, (3) 29 ambient water quality monitoring sites, and (4) 16 stations with continuous operation during selected low flow periods. In addition, active combined sewer overflows shall be sampled, five sediment oxygen demand tests shall be performed on the Fox River mainstem, and bed substrate from ten sites shall be analyzed. Preliminary site locations are identified.
		Date Created:	12 21 2005
		Agency ID:	CR-2005-13
		ISL ID:	000000000940 Original UID: 999999994470 FIRST WORD: Overview

132:		Title:	A method for estimating groundwater contribution areas for Illinois nature preserves and other natural areas.
		Volume/Number:	2005
		Issuing Agency:
		Description:	A new method for estimating the groundwater contribution area (GCA) for Illinois nature preserves was demonstrated using 12 test sites (Bluff Springs Fen, Braidwood Dunes and Savanna, Elizabeth Lake, George B. Fell, Goose Lake, Illinois Beach, Lake in the Hills Fen, Lockport Prairie, Parker Fen, Romeoville Prairie, Spring Grove Fen, and Volo Bog). The sites were selected for their varied hydrogeologic settings and available hydrogeologic data. None of the sites had sufficient local groundwater studies available to identify an entire GCA. Regional studies available for six preserves readily could be used to identify a regional GCA. The amount of hydrogeologic data available for any given preserve will vary, but for most Illinois nature preserves groundwater studies are not available to evaluate groundwater flow conditions. Because contribution areas must be determined to address site management issues, this new method accommodates those sites by identifying GCAs using available information. In particular, it uses published hydrologic and geologic data, if available, as well as uncompiled water-level data, and proxy data adjusted by best professional judgment to account for significant features affecting shallow, unconfined groundwater flow. Surface watersheds were delineated and adjusted based on significant hydrologic features (e.g., water elevations in ponds, streams, and wetlands; infrastructure such as ditches, sewers, and roadways) to develop adjusted surface watershed areas (ASWAs) for all 12 sites. These ASWAs and regional GCAs were compared to determine the viability of substituting ASWAs for regional GCAs at preserves lacking groundwater-level data. The ASWAs identified between 7 and 68 percent of the regional GCAs. More importantly, the ASWAs included the most hydrologically significant locations directly upgradient of each preserve. Use of an ASWA to estimate groundwater flow will not be effective in some hydrogeologic settings, including those where confined groundwater sources, karst terrains, and significant groundwater withdrawals may be a factor. Regional GCAs and ASWAs were combined at each site to create final GCAs that attempt to identify all areas that could contribute groundwater to a nature preserve. Final GCA estimates presented in this report will be useful to determine areas where a Class III (also known as Special Resource) groundwater designation could be applied under Title 35 Section 620.230(b) of the Illinois Administrative Code. They also identify areas of important groundwater resources where it may be most effective to focus management or acquisition efforts to ensure preserve integrity.
		Date Created:	1 25 2006
		Agency ID:	CR-2005-11
		ISL ID:	000000000941 Original UID: 999999994471 FIRST WORD: A

133:		Title:	Watershed monitoring for the Lake Decatur watershed, 2000-2003.
		Volume/Number:	2005
		Issuing Agency:
		Description:	Lake Decatur is the water supply reservoir for the City of Decatur. The reservoir was created in 1922 by constructing a dam to impound the flow of the Sangamon River. The dam was modified in 1956 to increase the maximum capacity of the lake to 28,000 acre-feet. The drainage area of the Sangamon River upstream of Decatur is 925 square miles and includes portions of seven counties in east-central Illinois, which are primarily in agricultural production. Lake Decatur has high concentrations of total dissolved solids and nitrates, and nitrate-nitrogen (nitrate-N) concentrations have been exceeding drinking water standards in recent years. This created a serious situation for the drinking water supply of the City of Decatur because nitrate-N cannot be removed from finished drinking water through regular water purification processes. Nitrate-N concentrations in Lake Decatur have exceeded the Illinois Environmental Protection Agency (IEPA) drinking water standard of 10 milligrams per liter (mg/L) on occasions each year between 1979 and 2002, except in 1993, 1994, 1995, and 2000. In June 2002, the City of Decatur activated a newly constructed nitrate-removal facility. Since 1993, the Illinois State Water Survey has been monitoring the Lake Decatur watershed for trends in nitrate-N concentrations and loads and to identify any significant changes in the watershed. The continued purpose of the monitoring is to collect reliable hydrologic and water quality data throughout the watershed for use by city planners to efficiently operate the nitrate removal facility and by resource managers to develop watershed management alternatives based on scientific data. This report presents annual data for 10 years of monitoring (May 1993-April 2003) and monthly data for Project Years (PYs) 8-10 of monitoring (May 2000-April 2003). Based on these data, it can be concluded that the average unit nitrate-N loads are relatively uniform over the entire watershed, but tend to be slightly higher at the tributary stations than at the Sangamon River stations. There also can be considerable differences in loads at tributary stations from year to year. Nitrate-N loads vary with concentration and streamflow. Average annual runoff has varied from 4 to 14 inches over the monitoring period. Concentrations were lowest in PY 7 and highest in PY 1 due to extremely low and high streamflows, respectively. Flow-weighted nitrate-N concentrations have been increasing at the Monticello and Big Ditch stations during the study period. The highest nitrate-N concentrations during the monitoring period were observed in PY 6 and PY 7. Area-weighted annual nitrate-N yield into Lake Decatur has varied between 10 (1999) and 38 (1998) lb/acre during the 10-year monitoring period (1993-2003).
		Date Created:	4 19 2006
		Agency ID:	CR-2005-09
		ISL ID:	000000000942 Original UID: 999999994472 FIRST WORD: Watershed

134:		Title:	The water cycle and water budgets in Illinois: A framework for drought and water-supply planning.
		Volume/Number:	2006
		Issuing Agency:
		Description:	Provision of adequate and reliable supplies of clean water at reasonable cost is a basic necessity for public health, the economy, recreation, and navigation. It is the goal of watersupply planning and management. As water withdrawals increase, so too does the need to protect watersheds, aquifers, and aquatic ecosystems for present and future generations. With sound planning and management, there is no reason why the residents of Illinois, a water-rich state, ever should face a water crisis. Without sound planning and management, however, current local problems and regional concerns could mushroom into conflicts and crises, and courts increasingly could be called upon to determine the reasonableness of withdrawals. The less desirable alternative to sound planning and management is to adopt a "wait-andsee" and "contingency" strategy to find out whether or not existing water-supply facilities can cope with the next major drought and economic and population growth as they occur. Other states have discovered during recent worst-case droughts that contingency planning, as practiced by many community water-supply systems in Illinois, is not a wise substitute for drought-preparedness planning. In Illinois, about 35 of 90 existing surface water-supply facilities (streams, reservoirs, pumps, pipelines, treatment facilities, etc.) likely would experience severe impacts during a 50-year drought, and worse droughts would have more serious impacts on an even greater number of public and private surface- and groundwater systems. On the basis of their shallow depth, proximity to other shallow community wells, and proximity to identified streams, 208 wells representing 82 communities are deemed potentially vulnerable to drought conditions. Drought impacts can be reduced by incorporating information on water availability and demand into evaluations of system capacity and then developing appropriate drought-tolerant capacities.
		Date Created:	7 10 2006
		Agency ID:	IEM-2006-02
		ISL ID:	000000000943 Original UID: 999999994485 FIRST WORD: The

135:		Title:	Prioritizing Illinois aquifers and watersheds for water supply planning.
		Volume/Number:	2006
		Issuing Agency:
		Description:	Four aquifer systems and five watersheds in Illinois are identified as most in need of attention for water supply planning and management purposes. The aquifers and watersheds are identified on the basis of limited water supply availability and substantial population and economic growth. Improved water supply planning and management of these aquifers and watersheds will help ensure current and future water demands can be met and conflicts minimized. Aquifers and watersheds are listed in order of priority regarding the potential benefit and relative urgency of water supply planning. In addition to potential planning needs for these aquifers and watersheds at regional scales, there is a need to also evaluate the adequacy of individual community water supply systems scattered throughout southern and central Illinois that likely will be susceptible to water supply shortages during a major drought. The following aquifer systems are recommended as most in need of study and planning: the deep bedrock aquifer system of northeastern Illinois, the sand and gravel and shallow bedrock aquifers of northeastern Illinois, the Mahomet Aquifer of east-central Illinois, and the American Bottoms of southwestern Illinois (MetroEast area), and the following watersheds are recommended for study and planning: the Fox River watershed, the Kaskaskia River watershed, the Sangamon River watershed, the Kishwaukee River watershed, and the Kankakee River watershed.
		Date Created:	8 1 2006
		Agency ID:	IEM-2006-04
		ISL ID:	000000000944 Original UID: 999999994486 FIRST WORD: Prioritizing

136:		Title:	The 2005 Illinois drought.
		Volume/Number:	2006
		Issuing Agency:
		Description:	Dry conditions in 2005 reached a historic level of severity in some parts of Illinois and ranked as one of the three most severe droughts in Illinois in 112 years of record. The timing of the dryness during the spring and summer, when water demand and use are high, ensured substantial impacts on agriculture and other sectors. The drought also had several unusual characteristics. The drought area was long and narrow, extending from south Texas to the Great Lakes, but within the Midwest, the drought had relatively minor impacts on states other than Illinois. A record number of remnants of hurricanes and tropical storms passed through Illinois during July, August, and September, substantially ameliorating drought conditions in portions of central and southern Illinois. Crop yields were surprisingly high in parts of the state, perhaps providing evidence of increased drought resistance in modern varieties and the benefits of timely rains.
		Date Created:	8 8 2006
		Agency ID:	IEM-2006-03
		ISL ID:	000000000945 Original UID: 999999994487 FIRST WORD: The

137:		Title:	Evaluation of the potential for photovoltaic power generation in Illinois
		Volume/Number:	2006
		Issuing Agency:
		Description:	Solar power production was estimated from hourly solar insolation data collected at 19 sites across Illinois from 1991-2004 by the Illinois State Water Survey (ISWS). Values were compared with more limited, experimental data and a solar radiation model reported in the literature. All prior data sources are in good agreement with the ISWS values with discrepancies noted. Based on analyses of the current Illinois data, an estimate was made of potential power production from small to medium-sized photovoltaic modules and systems in Illinois. ISWS insolation data were converted from observed values using flat-plate pyramometers oriented horizontally, to expected values from south-facing sensors tilted from horizontal by the latitude of each station, a typical orientation of photovoltaic systems. Champaign, Illinois, centrally located in the state, was chosen as a hypothetical solar power array site. A large operational array in Arizona was used as a model of photovoltaic system performance. Expected differences in power production due to technologies chosen for the hypothetical array and climatological conditions in Illinois as compared to the model array were considered. The use of concentrated solar collectors was not explored. The expected power output based on two array designs was calculated to be 134-180 kilowatt hours per square meter of array per year. Considering the unsubsidized cost of a photovoltaic array necessary to provide power for an individual dwelling, the system cannot expect to match grid power on a cost basis at this time. However, the comparison becomes more favorable in relatively remote locations where transmission lines for grid connection must be established. That is, photovoltaics may be cost effective for small remote applications such as powering billboards, but generally not for homes or businesses. Cost effectiveness of photovoltaics increases significantly when major subsidies and economy-of-scale discounts in both module and balance-of-system costs are available to reduce the initial system price and with designs of large-scale array systems. Photovoltaics also may be worth considering to offset the most expensive power produced by utilities, peak power, and for distributed power generation providing grid support.
		Date Created:	8 17 2006
		Agency ID:	IEM-2006-05
		ISL ID:	000000000946 Original UID: 999999994488 FIRST WORD: Evaluation

138:		Title:	Impact of irrigation on the dynamics of nitrate movement in a shallow sand aquifer.
		Volume/Number:	1999
		Issuing Agency:
		Description:	A field-scale project in Mason County, Illinois, was performed to monitor the movement of nitrate in ground water beneath an irrigated field. Chemical tracers were used to assess the migration of solutes both laterally and vertically under the influence of an irrigation well and to determine the amount of recycling at a site due to irrigation pumpage and the amount of off-site transport of nitrate due to regional ground-water flow. Water samples from the sand aquifer at the site reveal considerable spatial and temporal heterogeneity in aqueous chemistry. Recharge is rapid in this system, and it is probable that the water chemistry of the recharge water also is variable spatially and temporally; it is especially influenced by agricultural practices. Nitrate (NO3-) concentrations are elevated in a zone between approximately 15 and 30 feet (ft) beneath the surface, although this zone was not persistent laterally or with time. The maximum nitrate concentrations in this zone were slightly greater than 20 milligrams per liter (mg/L) as nitrogen, well above the drinking water standard of 10 mg/L. Nitrate was generally absent below 30 ft in the aquifer, probably due to denitrification reactions. The tritium data suggest that vertical movement of solutes in the aquifer is rapid, and that there has been enough time to transport solutes from the surface or soil zone to depths in excess of 100 ft. Because drinking-water wells generally are screened well below the zone of elevated nitrate concentrations in this area, it appears that fertilizer applications do not have a negative effect on drinking-water quality for most homeowners. From the results of tracer tests, the effects of irrigation pumping on solute transport are measurable but not substantial. Tracer movement both horizontally and vertically was slight under pumping conditions, less than 10 ft horizontally and between 1 and 2 ft vertically about 100 ft from the irrigation well after three days of pumping. The vast majority of nitrate applied in this area is not being recycled through the irrigation wells.
		Date Created:	9 24 2004
		Agency ID:	RR-128
		ISL ID:	000000000947 Original UID: 999999994252 FIRST WORD: Impact

139:		Title:	Long-term variations in seasonal weather conditions and their impacts on crop production and water resources in Illinois
		Volume/Number:	1999
		Issuing Agency:
		Description:	An analysis of long-term records of corn yields, water resource conditions, and seasonal weather conditions in Illinois found major temporal shifts and important spatial variations in the types of seasonal weather conditions that have positive and negative impacts on yields and water conditions. Nineteen different types of corn-weather seasons (May-August) occurred during 1901-1997, of which nine types accounted for most of the high corn yields (highest 20 of the 97 values) and eight types produced most low yields (lowest 20 values). An assessment of the years with either high or low yields revealed three findings about the distributions of the corn-weather seasons creating these extremes: 1) some types were uniformly distributed throughout the century; 2) others were unevenly distributed over time, some occurring only in the century's early decades and others only in the last few decades; and 3) certain types varied greatly regionally. Yield responses to certain seasonal types varied over time. The findings helped establish that changes in farming practices, corn varieties, and agricultural technology all affect how a given type of growing season affects corn yields. Sizable regional differences in yield outcomes from a given set of weather conditions, a result of varying soil and climate differences across Illinois, further revealed how impacts of similar seasonal weather conditions can vary spatially. These two conclusions revealed the importance of using weather effects in defining seasonal extremes. In general, the statewide results showed that the types of seasons creating high yields predominated during 1901-1910 and 1961-1997, and most seasons creating low yields were concentrated in 1911-1920, 1931-1940, and 1951-1960. Major seasonal weather effects on Illinois' water resources (surface water supplies, ground-water supplies, and water quality) were found to occur in the spring and summer seasons. Two conditions caused these effects in each season: either above normal temperatures and below normal precipitation, or above normal temperatures and precipitation. Spring impacts on water resources were typically mixed, some negative and some positive, whereas impacts from summer season extremes had largely negative impacts on water supplies and water quality. More impacts, positive and negative, occurred in southern Illinois than elsewhere, and most of the seasons having negative impacts on water resources occurred in Illinois during 1911-1960. Comparison of the 1901-1997 temporal distributions of yield extremes (high and low) and the negative summer water resource impacts with the temporal distributions of cyclone passages and the incidence of El Nio Southern Oscillation conditions that affect spring and summer weather conditions revealed a generally good relationship. Periods with many seasons creating numerous negative impacts on corn yields and water resources occurred in several decades (1911-1920, 1931-1940, and 1951-1960) when the number of cyclones was low and most incidences of La Nia conditions that create warm temperatures and negative impacts prevailed. Conversely, when seasonal weather conditions were generally beneficial (1901-1910, 1961-1970, and 1981-1997), Illinois had relatively large numbers of cyclone passages and most El Nio-related cool and wet summers occurred. Consideration needs to be given to the shifting temporal responses to various kinds of seasonal weather conditions during the 20th century to determine how future climatic conditions may affect Illinois' agriculture and water resources. Furthermore, some influential seasonal weather types appeared sporadically, some only during the early decades of the century and others only in the latter decades. Thus, data from the past 97 years reveal that efforts to project impacts of future climate conditions on agriculture and water resources may be difficult and subject to considerable error.
		Date Created:	9 24 2004
		Agency ID:	RR-127
		ISL ID:	000000000948 Original UID: 999999994058 FIRST WORD: Long

140:		Title:	Insights to key questions about climate change
		Volume/Number:	2004
		Issuing Agency:
		Description:	This report presents extensive information from recently published findings related to the following two critical questions about climate change: andlt;ULandgt; andlt;LIandgt;What will the future climate be like? andlt;LIandgt;What will the effects be, both good and bad? andlt;/LIandgt;andlt;/ULandgt;Chapter 1 introduces the two main chapters of the report that provide insights to the above two critical questions about climate change. Chapter 2 provides examples from a wide spectrum of scientists, scientific organizations, and the media of contradictions and confusion about whether human-induced climate change is predictable over the time scale of a century. It then explains why such climate change is unpredictable in the traditional deterministic sense. It describes the climate system and documents improvements and remaining uncertainties of global climate models relevant to evaluating human-induced climate change on the century time scale. Climate measurements in Illinois since the mid-19th century document major climate swings not evident in a 50- to 100-year record. Illinois is no warmer or wetter today than it has been over the last 150 years, and extreme precipitation events across the country are reported to be no more frequent than they were a century ago. Important conclusions from these data are that i) regional climate trends over the past 50-100 years that are consistent with theoretical expectations of an enhanced greenhouse effect (for example, higher precipitation and more heavy rainfall events in northern mid-latitudes) do not necessarily establish causality; and ii) global warming has not resulted in warming in all parts of the globe. Chapter 3 focuses on the issue of economic impacts of weather and climate in the United States (US). The first section addresses known financial impacts of recent (1950-2000) weather and climate conditions. Descriptions follow of temporal trends of weather and climate extremes and their impacts, causes for on-going increases in economic impacts, and estimates of future financial impacts under a changed climate. The frequency of most types of storms and droughts either has not changed or has decreased during 1940-2000. Yet, losses (1997 dollars) for most storm types have increased over time. Possible causes for increased losses include a shift in climate related to global warming, questionable insurance practices, and aging infrastructure. Study also shows increasing losses due to societal factors, including population growth, more people residing in more weather vulnerable areas, shifts in business-product development that are weather sensitive, and growing wealth. Various studies of weather- and climate-induced economic impacts were used to develop national loss and gain estimates. Projections for the US, depending upon varying assumptions about the future climate (combinations of warmer, wetter, drier, or more storms), show annual climate-related losses ranging from $2 billion to $69 billion, and others estimate annual gains of $30 billion to $40 billion. In all cases, the projected outcomes are small in relation to the expected Gross Domestic Product.
		Date Created:	9 24 2004
		Agency ID:	IEM-2004-01
		ISL ID:	000000000949 Original UID: 999999994422 FIRST WORD: Insights

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