| | 1241: | | Title: | | | | | Volume/Number: | | | | | Issuing Agency: | | | | | Description: | Illinois Taxing District Map for Tax Year 2005. Geospatial data representing taxing district boundary information collected from Illinois county clerks. Map identifies the boundaries of property tax districts to be used for general illustration and research. | | | | Date Created: | 01 31 2006 | | | | Agency ID: | | | | | ISL ID: | 000000000926 Original UID: 877 FIRST WORD: Mercer | |
| 1242: | | Title: | | | | | Volume/Number: | | | | | Issuing Agency: | | | | | Description: | Illinois Taxing District Map for Tax Year 2005. Geospatial data representing taxing district boundary information collected from Illinois county clerks. Map identifies the boundaries of property tax districts to be used for general illustration and research. | | | | Date Created: | 01 31 2006 | | | | Agency ID: | | | | | ISL ID: | 000000000927 Original UID: 878 FIRST WORD: Monroe | |
| 1243: | | Title: | | | | | Volume/Number: | 1963 | | | | Issuing Agency: | | | | | Description: | Systematic measurements of ground-water levels in Illinois were started in the early 1930s in the Chicago region. Measurements were made in 1961 in 220 observation wells in 42 counties throughout the state. In areas remote from pumping centers, no long-term continuing trends of general rise or decline of the water table are discernible. A large part of central and southern Illinois experienced a severe drought beginning early in 1952 and ending in most areas during the spring of 1955. As a result, ground-water levels declined to record-low stages especially in the southern one-half of Illinois. However, large quantities of ground water taken from storage within the ground-water reservoir were replenished during succeeding years as precipitation increased. In heavily pumped areas, changes in water levels caused by pumping are superimposed on seasonal and secular fluctuations due to natural phenomena.In some instances large developments of ground water have caused pronounced and serious declines of water levels. There are many areas of ground-water development where serious water-level declines have not occurred. | | | | Date Created: | 9 24 2004 | | | | Agency ID: | RI-45 | | | | ISL ID: | 000000000928 Original UID: 999999993909 FIRST WORD: Ground | |
| 1244: | | Title: | | | | | Volume/Number: | 1963 | | | | Issuing Agency: | | | | | Description: | In northern Illinois large quantities of ground water are withdrawn from wells in shallow dolomite aquifers of Silurian and Ordovician age. The Niagaran and Alexandrian Series of Silurian age and the Galena-Platteville Dolomite of Ordovician age yield moderate to large quantities of ground water. Dolomite beds of the Maquoketa Formation of Ordovician age yield small quantities of water to wells. Silurian rocks are usually encountered at depths of between 10 and 300 feet in northeastern Illinois and between 30 and 880 feet in northwestern Illinois. These rocks exceed 450 feet in thickness at places and are often overlain by glacial drift. The average depth of shallow doIomite weIIs is about 140 feet, and most wells of recent design are finished 12 to 16 inches in diameter. About 1000 well-production tests were made, 1921-1961, on more than 800 shallow dolomite wells. Statistical analysis of specific-capacity data provided a basis for determining 1) the role of individual shallow dolomite aquifers or formations, uncased in wells, as contributors of water; 2) whether or not significant relationships exist between the yields of wells and geohydrologic controls; and 3) the effects of acid treatment on the productivities of wells. It is concluded that the Niagaran Series, Alexandrian Series, and Galena-Platteville Dolomite all have similar moderate to high yields and inconsistency of yields in areas throughout northern Illinois where these rocks directly underlie glacial drift. These Silurian and Ordovician rocks have similar low yields and inconsistency of yields in areas where these rocks are overlain by bedrock. On the other hand, the Maquoketa Formation and rocks of Devonian age yield very little water to wells. Most water-yielding openings occur in the upper one-third of the shallow dolomite aquifers. There is a good connection between glacial drift and the upper part of the shallow dolomite aquifers. Highest yielding wells are found in bedrock upland areas, in areas where the glacial drift immediately overlying the shallow dolomite aquifers is composed of sand and gravel, and in areas where reefs and associated strata are present. Most dolomite wells treated with acid show significant improvement in yield; largest improvements are recorded for rehabilitated wells. Yields are increased because water-yielding openings are enlarged and fine drill cuttings or incrustations are removed from openings. Probable ranges in yields of shallow dolomite wells in undeveloped areas are estimated from specific-capacity frequency graphs, aquifer thickness and area1 geology maps, and waterlevel data. | | | | Date Created: | 6 17 2005 | | | | Agency ID: | RI-46 | | | | ISL ID: | 000000000929 Original UID: 999999993910 FIRST WORD: Yields | |
| 1245: | | Title: | | | | | 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 | |
| 1246: | | Title: | | | | | 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 | |
| 1247: | | Title: | | | | | 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 | |
| 1248: | | Title: | | | | | 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 | |
| 1249: | | Title: | | | | | 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 | |
| 1250: | | Title: | | | | | Volume/Number: | 1983 | | | | Issuing Agency: | | | | | Description: | | | | | Date Created: | 9 24 2004 | | | | Agency ID: | RI-103 | | | | ISL ID: | 000000000935 Original UID: 999999993966 FIRST WORD: Hydrology, | |
| 1251: | | Title: | | | | | 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 | |
| 1252: | | Title: | | | | | 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 | |
| 1253: | | Title: | | | | | 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 | |
| 1254: | | Title: | | | | | 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 | |
| 1255: | | Title: | | | | | 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 | |
| 1256: | | Title: | | | | | 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 | |
| 1257: | | Title: | | | | | 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 | |
| 1258: | | Title: | | | | | 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 | |
| 1259: | | Title: | | | | | 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 | |
| 1260: | | Title: | | | | | 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 | |
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