| | 821: | | Title: | | | | | Volume/Number: | | | | | Issuing Agency: | | | | | Description: | Citation for failure to maintain corporate status. | | | | Date Created: | 09 26 2006 | | | | Agency ID: | 06-0488 | | | | ISL ID: | 000000000854 Original UID: 842 FIRST WORD: Order | |
| 822: | | Title: | | | | | Volume/Number: | 2001 | | | | Issuing Agency: | | | | | Description: | The Illinois Streamflow Assessment Model (ILSAM) is an analytical and information tool developed to predict the frequency of streamflows, and water use impacts on streamflows, for every stream in selected major watersheds in Illinois. The current version of ILSAM was developed to operate on a personal computer having a Microsoft Windows 95/98/2000/NT operating system. The model user can obtain streamflow frequency estimates for any location in the watershed by identifying the desired stream and location. The ILSAM has been developed for use with streams in five such watersheds: the Sangamon, Fox, Kaskaskia, Kankakee, and Little Wabash River. This report includes a description of the steps used to develop ILSAM for application to the Little Wabash River watershed, along with a description of the physical characteristics of the watershed, its surface water hydrology, and the factors that influence streamflow variability. The Little Wabash River watershed is located in the southeastern portion of Illinois and has a total area of approximately 3238 square miles. The river and its major tributaries provide the source of water supply for all of the major communities in the watershed, either through direct withdrawals from the river or from the storage of water in impounding reservoirs. Many of these communities were forced to undertake emergency measures to sustain their water supply from these sources during the major droughts of the early- and mid-1900s. Thus, an understanding of the frequency of low flows and drought flows is critical for assessing surface water availability and yields for these communities. Streamflow frequency predictions produced by the model are also useful for evaluating instream flow levels for the protection of aquatic habitat, providing streamflow estimates for water quality analyses and regulations, and classifying Illinois streams by their hydrologic character for use in watershed management. The hydrologic analyses used to develop the model include evaluating the flow frequency from all streamgage records in the Little Wabash River region, evaluating impacts to flow quantity from dams, water supply, and treated wastewaters, and developing regional equations to estimate flows at ungaged sites throughout the watershed. All streamflow frequency estimates produced by the model are representative of the long-term expected flow conditions of streams, reflecting hydrologic conditions over a base period of nearly 50 years (1952-1999). | | | | Date Created: | 9 24 2004 | | | | Agency ID: | CR-2001-14 | | | | ISL ID: | 000000000855 Original UID: 999999994330 FIRST WORD: Streamflow | |
| 823: | | Title: | | | | | Volume/Number: | 2001 | | | | Issuing Agency: | | | | | Description: | The Illinois State Water Survey (ISWS), under contract to the Imperial Valley Water Authority (IVWA), has operated a network of rain gauges in Mason and Tazewell Counties since August 1992. The ISWS also established a network of groundwater observation wells in the Mason-Tazewell area in 1994. These networks are located in the most heavily irrigated region of the state. The region's major source of water for irrigation, municipal, and domestic water supplies is groundwater pumped from thick sand-and-gravel deposits associated with the confluence of two major ancient river valleys, the Mississippi and the Mahomet-Teays. Relatively recent extreme weather events (e.g., the drought of 1988 and the great flood of 1993) resulted in large fluctuations in groundwater levels in the Imperial Valley area. The purpose of the rain gauge network and the groundwater observation well network is to collect long-term data to determine the rate of groundwater drawdown in dry periods and during the growing season, and the rate at which the aquifer recharges. This report presents data accumulated from the rain gauge and observation well networks since their inception through August 2000. Precipitation is recorded continuously at 20 rain gauges for each storm that traverses the Imperial Valley. Groundwater levels at the 13 observation wells are measured the first of each month. The database from these networks consists of eight years of precipitation data and six years of groundwater observations. At the beginning of groundwater observations in late 1994, the water levels were at their highest in the six years of observation. These high groundwater levels were the result of the very wet 1992-1995 period when annual precipitation was above the 30-year normals at both Havana and Mason City. From September 1995-August 1997, precipitation in the region was well below the 30-year normal followed by the 1997-1998 and 1998-1999 observation years with rainfall totals that were slightly above and slightly below normal, respectively. Groundwater levels in the observation wells reflected the multi-year rainfall patterns, showing a general downward trend during the dry years, a recovery in the wet 1997-1998 year, and a leveling off in 1998-1999. Precipitation in the region during observation year 1999-2000 was well below normal, mirroring the quite low totals observed during the dry years of 1995-1997. In response, groundwater levels fell to levels similar to those experienced in 1996-1997. Analysis indicates that groundwater levels are affected by both the precipitation in the Imperial Valley area and, for wells close to the Illinois River, by river stage. Generally, water levels in wells follow antecedent precipitation and Illinois River stage by one to two months, i.e., June groundwater levels are most highly correlated with the Illinois River stage or precipitation that occurs in April or May. The analyses conducted indicate the need for continued operation of both networks due to inconsistencies associated with groundwater levels, precipitation, and the Illinois River stage. For instance, although observation well number 2 (MTOW-2) is located near the center of Mason County, well away from the Illinois River, it has an equal correlation with the Illinois River stage and area precipitation. Additional data collection and analyses are needed to determine the reasons for this and other data disparities. | | | | Date Created: | 9 24 2004 | | | | Agency ID: | CR-2001-15 | | | | ISL ID: | 000000000856 Original UID: 999999994332 FIRST WORD: Operation | |
| 824: | | Title: | | | | | Volume/Number: | 2001 | | | | Issuing Agency: | | | | | Description: | This report documents the structure and the use of a windows-based interface developed by the Illinois State Water Survey for the Office of Water Resources, Illinois Department of Natural Resources. The current version of the interface program is able to download historic, real-time, and forecasted stage and flow data from the U.S. Geological Survey, U.S. Army Corps of Engineers, and the National Weather Service websites interactively. These data are used to update existing Data Storage System (DSS) database or to create new ones; to run the UNET model for historic, design, real-time, and forecasted flood events in the Lower Illinois River; and to post-process model outputs from DSS files in tabular and graphical formats.. This interface program uses the original UNET generic geometry and boundary condition files to maintain the same level of accuracy as the UNET model, but it also allows the user to change some of the parameters, such as, the simulation time interval, time windows, and numerical Corant number, and etc., in the BC file. The real-time simulation of a flood event simulates the flood stage profiles using forecasted stage and real-time flow data downloaded from related websites. With the primary focus on simulations of levee failures, the interface program lets the users modify parameters to simulate simple levee failures through the simple spillway approach for two types of complicated embankment failures, overtopping and piping. A new simulation can be performed using the modified levee information. The change of water surface elevation induced by modifying the levees can be compared with another simulation graphically and also in table format. Stage profiles from all the simulations can be plotted together with the levee heights on both sides of the channel along the Lower Illinois River to provide a visual view of the locations of overtopping. Overtopping locations and magnitudes will be tabulated should they occur. | | | | Date Created: | 9 24 2004 | | | | Agency ID: | CR-2001-16 | | | | ISL ID: | 000000000857 Original UID: 999999994333 FIRST WORD: Management | |
| 825: | | Title: | | | | | Volume/Number: | 2001 | | | | Issuing Agency: | | | | | Description: | The Cache River located in the southernmost part of Illinois flows through an area containing the Cache River Wetlands. These unique and important wetlands were designated as a Ramsar Site in 1996. Drainage activities divided the Cache River in half in the early 1900s, effectively separating the river into the Upper and Lower Cache Rivers. The Lower Cache River contains a remnant of a vast wetland system called the Lower Cache River State Natural Area (LCRSNA), commonly referred to as Buttonland Swamp. Sediment inflow from several tributary streams has an impact on the wetland. Previous research has determined that 217,000 tons of sediment were deposited in Buttonland Swamp between 1986 and 1988. The wetlands of the Lower Cache River have been targeted for preservation and restoration by state, federal, and private environmental organizations. A program to monitor the sediment deposition rate within the wetland area at regular intervals would be useful in evaluating and guiding preservation and restoration efforts. This project established a benchmark measure of the deposition rates and cross-sectional profiles at selected locations in the LCRSNA wetland. | | | | Date Created: | 9 24 2004 | | | | Agency ID: | CR-2001-17 | | | | ISL ID: | 000000000858 Original UID: 999999994334 FIRST WORD: Benchmark | |
| 826: | | Title: | | | | | Volume/Number: | 2002 | | | | 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. Lake Decatur has high concentrations of total dissolved solids and nitrates, and nitrate-N concentrations have been exceeding drinking water standards in recent years. This has created a serious situation for the drinking water supply of the City of Decatur, since nitrate-nitrogen (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 for the period between 1970 and 2000, except from 1993 to 1995. 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 purpose of the monitoring is to collect reliable hydrologic and water quality data throughout the watershed for use by city planners and resource managers to develop watershed management alternatives based on scientific data. This report presents the annual data for all seven years of monitoring (May 1993-April 2000) and monthly data for Year 7 of monitoring (May 1999-April 2000). Based on the seven years of data, it can be concluded that the unit of nitrate-N loads are relatively uniform over the entire watershed but tend to be slightly higher at the tributary streams in the upper Sangamon River watershed than at the Sangamon River stations closer to the lake. Nitrate-N loads vary with concentrations and streamflow and were the lowest in Year 7 because of the low streamflows during that year. Flow-weighted nitrate-N concentrations have been increasing during the study period at the Monticello station. The highest nitrate-N concentrations during the monitoring period were observed in years 6 and 7. | | | | Date Created: | 9 24 2004 | | | | Agency ID: | CR-2002-01 | | | | ISL ID: | 000000000859 Original UID: 999999994336 FIRST WORD: Watershed | |
| 827: | | Title: | | | | | Volume/Number: | 2002 | | | | Issuing Agency: | | | | | Description: | A dense raingage network has operated in Cook County since the fall of 1989, to provide accurate precipitation for use in simulating runoff for Lake Michigan diversion accounting. This report describes the network design, the operations and maintenance procedures, the data reduction and quality control methodology, a comparison of rainfall amounts obtained via analog chart and data logger, and an analysis of precipitation for Water Year 2001 (October 2000 - September 2001). The data analyses include 1) monthly and Water Year 2001 amounts at all sites, 2) Water Year 2001 amounts in comparison to patterns from network Water Years 1990-2000, and 3) the 12-year network precipitation average for Water Years 1990-2001. Also included are raingage site descriptions, instructions for raingage technicians, documentation of raingage maintenance, and documentation of high storm totals. | | | | Date Created: | 9 24 2004 | | | | Agency ID: | CR-2002-03 | | | | ISL ID: | 000000000860 Original UID: 999999994340 FIRST WORD: Operation, | |
| 828: | | Title: | | | | | Volume/Number: | 2002 | | | | Issuing Agency: | | | | | Description: | Riparian forests have been proposed by the Technical Advisory Subcommittee of the Upper Embarras River Basin Commission in its alternatives for mitigating flood damages in the Village of Villa Grove and nearby farmlands. In order to evaluate potential reduction in flood stages in Villa Grove, methods for accounting for flow resistances induced by the riparian forests are needed in the hydraulic model for the Upper Embarras River. This project has been designed to better apply the available knowledge in practical field applications, particularly, how to evaluate the vegetal roughness in terms of Manning's andlt;EMandgt;nandlt;/EMandgt; coefficient for specified planting scenarios. Approaches presented in this report are literature review on Manning's roughness with emphasis on vegetative roughness, and evaluation and selection of methods for computing vegetative roughness due to riparian forests. The Petryk and Bosmajian (1975) method was selected for evaluating Manning's andlt;EMandgt;nandlt;/EMandgt; for mature trees because parameters could be reasonably obtained with available general field information. Using this approach, effects of riparian forest on floods were evaluated with the scenarios that the two-year floodplain has two densities of trees. The study reach was the channel between Villa Grove and Camargo. Also investigated were the options of having uniform tree density for the whole reach or half of the reach. An interface has been developed for implementing the computed andlt;EMandgt;nandlt;/EMandgt; values to a HEC-RAS hydraulic model, and capacity curves were developed to illustrate the effects on flood conveyance among these scenarios. The capacity curves thoroughly included possible boundary conditions and were presented in simple nomographs that relate discharge and downstream elevations to a specified flood elevation in Villa Grove. Therefore it was easier to evaluate the resulting effects of different alternatives. | | | | Date Created: | 9 24 2004 | | | | Agency ID: | CR-2002-02 | | | | ISL ID: | 000000000861 Original UID: 999999994341 FIRST WORD: Effects | |
| 829: | | Title: | | | | | Volume/Number: | 2002 | | | | Issuing Agency: | | | | | Description: | The Fox Chain of Lakes is a series of interconnected glacial lakes that are essentially located along the main stem of the Fox River. Originating in Wisconsin, the Fox River flows through northern Illinois before becoming a major tributary of the Illinois River. About 75 percent of the Fox River above the lowest section of the Fox Chain of Lakes lies in Wisconsin. The drainage area above the lowest point of the chain is about 1,184 square miles. The Fox Chain of Lakes has a surface area of more than 6,000 acres. Over the years, significant land-use changes have occurred on this watershed. These changes and the geographical location of the Fox River have resulted in extensive sediment deposition within these lakes. This is especially true for those lakes in the direct path of the Fox River. For example, Grass Lake and Nippersink Lake have lost most of their capacities to sediment deposition. The average depth of Grass Lake in 1975 was 2.7 feet, and the sediment is extremely soft. Within the present research activity, the original research conducted in 1974-1975 by the authors is being examined along with additional data collected by others within the last 25 years. These initial analyses indicated that both in-lake and off-lake sediment management techniques must be implemented to increase water depths within the lakes and decrease sediment loads. Among the in-lake management alternatives that should be considered are dredging and disposing of sediment outside the lake, discharging hydraulically dredged sediment into geotubes or some other type of containment facility within the lake, and creating artificial islands within the lake with dredged sediments. The watershed-based sediment management alternatives could include implementation of best management practices on the watershed, flow and sediment retention basins, side channel sediment traps, sediment management within the stream channel, and the implementation of a systemwide sediment management alternative. | | | | Date Created: | 9 24 2004 | | | | Agency ID: | CR-2002-04 | | | | ISL ID: | 000000000862 Original UID: 999999994342 FIRST WORD: Sediment | |
| 830: | | Title: | | | | | Volume/Number: | 2002 | | | | Issuing Agency: | | | | | Description: | The project objective was to assimilate the best available data to prepare digital maps of critical riparian corridors and areas at risk of flooding for the upper Embarras River, East Branch Embarras River, and Black Slough in Champaign County. Hydrologic, hydraulic, and digital data defining streams and floodplains were reconciled with digital orthophotos of the Embarras watershed. Using orthophotos as base maps, digital data sets were prepared of streams and rivers and floodplain boundaries expected for a flood having a one percent chance of occurrence in any given year. These maps were developed to provide easy-to-interpret information that identifies areas at risk during flood events. The maps were developed using ESRI ArcGIS 8.1 software and are on the attached CD-ROM in ready-to-print PDF format. The CD-ROM format is compatible with Microsoft Windows Operating System Version 95 or later. The CD-ROM contains the HEC-RAS hydraulic model used to simulate flood elevations, digital coverages used to compose the maps, digital photos of bridge crossings and landscapes of the watershed, and this report. Graphs of channel thalweg and water surface profiles showing the depth of flooding for the biennial flood event (2-year flood) and the one-percent annual chance of occurrence flood (100-year flood) provide additional information. | | | | Date Created: | 9 7 2005 | | | | Agency ID: | CR-2002-05 | | | | ISL ID: | 000000000863 Original UID: 999999994343 FIRST WORD: Embarras | |
| 831: | | Title: | | | | | Volume/Number: | | | | | Issuing Agency: | | | | | Description: | Petition to Withdraw Certificate of Service Authority. | | | | Date Created: | 09 26 2006 | | | | Agency ID: | 06-0580 | | | | ISL ID: | 000000000864 Original UID: 848 FIRST WORD: Order | |
| 832: | | Title: | | | | | Volume/Number: | | | | | Issuing Agency: | | | | | Description: | Citation for failure to file Annual Report. | | | | Date Created: | 09 13 2006 | | | | Agency ID: | 06-0498 | | | | ISL ID: | 000000000865 Original UID: 855 FIRST WORD: Order | |
| 833: | | Title: | | | | | Volume/Number: | | | | | Issuing Agency: | | | | | Description: | Application for a Certificate of Local Exchange Authority to Operate as a Facilities-based Carrier and Reseller of Telecommunications Services throughout the State of Illinois. | | | | Date Created: | 09 13 2006 | | | | Agency ID: | 06-0512 | | | | ISL ID: | 000000000866 Original UID: 856 FIRST WORD: Order | |
| 834: | | Title: | | | | | Volume/Number: | | | | | Issuing Agency: | | | | | Description: | Application for a Certificate of Interexchange Authority to Operate as a Reseller of Telecommunications Services Throughout the State of Illinois. | | | | Date Created: | 09 13 2006 | | | | Agency ID: | 06-0515 | | | | ISL ID: | 000000000867 Original UID: 857 FIRST WORD: Order | |
| 835: | | Title: | | | | | Volume/Number: | 2002 | | | | Issuing Agency: | | | | | Description: | Fall application of nitrogen (N) fertilizer is a common practice in Illinois to help overcome the uncertainties of spring field work and to reduce the potential for delay in planting of spring crops. If, however, the N is applied while soil temperatures are above 50F, significant N losses can occur before the crop can take up the N. The lost N can pollute the state's water supplies, resulting in harm to the environment. The objective of this work was to provide agricultural community and public access to near real-time, 4-inch bare soil temperatures measured at 10:00 a.m. Central Standard Time (CST) each day. Hourly soil temperatures are measured at 18 automated weather stations in Illinois operated by the Illinois State Water Survey (ISWS). These stations make up the Illinois Climate Network (ICN). Measured weather variables include 4-inch sodded soil temperature, solar radiation, air temperature, relative humidity, barometric pressure, precipitation, and wind speed and direction. These data are collected, quality controlled, and placed on a Web site (http://www.sws.uiuc.edu/warm/soiltemp.asp) for public access. Daily maps of the 4-inch bare soil temperature are derived from a combination of actual 4-inch bare soil measurements at 8 ICN stations and computed bare soil temperature from 4-inch sodded soil temperature measurements from the remaining 10 sites. These maps allow users to see the general pattern of the 10:00 a.m. CST soil temperature from which they can estimate soil temperature at a given location. The other measured weather variables also are presented on the Web site in map format. Steven E. Hollinger and Robert W. Scott, Water and Atmosphere Resources Monitoring Program, Atmospheric Environment Section and Office of the Chief, Illinois State Water Survey, 2204 Griffith Drive, Champaign, Illinois 61820-7945 | | | | Date Created: | 9 24 2004 | | | | Agency ID: | CR-2002-06 | | | | ISL ID: | 000000000868 Original UID: 999999994344 FIRST WORD: Real | |
| 836: | | Title: | | | | | Volume/Number: | 2002 | | | | Issuing Agency: | | | | | Description: | The Illinois State Water Survey (ISWS), under contract to the Imperial Valley Water Authority (IVWA), has operated a network of rain gauges in Mason and Tazewell Counties since August 1992. The ISWS also established a network of groundwater observation wells in the Mason-Tazewell area in 1994. These networks are located in the most heavily irrigated region of the state. The region's major source of water for irrigation and municipal, industrial, and domestic water supplies is groundwater pumped from thick sand-and-gravel deposits associated with the confluence of two major ancient river valleys, the Mississippi and the Mahomet-Teays. Recent extreme weather events (e.g., the drought of 1988 and the great flood of 1993) resulted in large fluctuations in groundwater levels in the Imperial Valley area. The rain gauge network and the groundwater observation well network collect long-term data to determine the rate of groundwater level decline in dry periods and during the growing season, and the rate of groundwater level recovery during recharge periods. This report presents data accumulated from the rain gauge and observation well networks since their inception through August 2001. Precipitation is recorded continuously at 20 rain gauges for each storm that traverses the Imperial Valley. Groundwater levels at the 13 observation wells are measured the first of each month. The database from these networks consists of nine years of precipitation data and seven years of groundwater observations. At the beginning of groundwater observations in late 1994, the water levels were at their highest in the seven years of observation. These high groundwater levels were the result of the very wet 1992-1995 period when annual precipitation was above the 30-year normals at both Havana and Mason City. From September 1995-August 1997, precipitation in the region was well below the 30-year normal followed by the 1997-1998 and 1998-1999 observation years with rainfall totals slightly above and slightly below normal, respectively. Groundwater levels in the observation wells reflected the multi-year rainfall patterns, showing a general downward trend during dry years, a recovery in wet 1997-1998, and a leveling off in near-normal 1998-1999, followed by declines in dry 1999-2000. Despite a dry July, near-normal precipitation in 2001 brought a return to more typical seasonal hydrographs. This report includes new regression analyses of data collected through August 2001, similar to regression analyses first conducted on data collected through August 1998. The analyses indicate that groundwater levels are affected by precipitation in the Imperial Valley area and, for wells close to the Illinois River, by river stage. Generally, water levels in wells follow antecedent precipitation and Illinois River stage by one to two months; e.g., a high correlation between June groundwater levels and the Illinois River stage or precipitation that occurs in April or May. However, additional data collected since 1998 did not improve the results of the regression analyses. In fact, coefficients of determination for many regressions worsened. This suggests that regressions of observed groundwater levels versus river stage and precipitation are not adequately describing all the variables affecting groundwater levels. Using the data collected to verify, test, and improve the existing Imperial Valley groundwater flow model is highly recommended. Continued data collection also is recommended to create long-term data sets of precipitation and groundwater levels for use in modeling analyses. Collection of additional groundwater level and irrigation pumpage data also is highly recommended. | | | | Date Created: | 9 24 2004 | | | | Agency ID: | CR-2002-07 | | | | ISL ID: | 000000000869 Original UID: 999999994345 FIRST WORD: Operation | |
| 837: | | Title: | | | | | Volume/Number: | 2002 | | | | Issuing Agency: | | | | | Description: | Sedimentation detracts from the use of any water-supply lake by reducing lake depth and volume, with a reduction of reserve water-supply capacity and possible burying of intake structures. Sedimentation of a reservoir is a natural process that can be accelerated or slowed by human activities in the watershed. Lake Decatur is located in Macon County, northeast of Decatur, Illinois. The location of the dam is 39 49' 28' north latitude and 88 57' 30' west longitude in Section 22, T.16N., R.2W., Macon County, Illinois. The dam impounds the Sangamon River in the Sangamon River basin. The watershed is a portion of Hydrologic Unit 07130006 as defined by the U.S. Geological Survey. The lake was constructed in 1922 with a spillway level of 610 feet above mean sea level (feet-msl). In 1956, a set of hydraulic gates was installed on the original spillway to allow variable lake levels from 610 feet-msl to 615 feet-msl. The portions of the lake surveyed for the present study were the Big and Sand Creek basins. These basins are the two major tributary stream basins formed to the south (Sand Creek) and east (Big Creek) of the main body of the lake. They receive the flow of Sand, Big, and Long Creeks. Lake Decatur has been surveyed to document sedimentation conditions nine times since 1930. Five of these survey efforts (1936, 1946, 1956, 1966, and 1983) were sufficiently detailed to be termed full lake sedimentation surveys. The survey discussed in detail in this report is not a full lake sedimentation survey. However, additional work included in the present study could be combined with the 2000 survey of Basin 6 of Lake Decatur to provide a complete baseline survey for future reference. Sedimentation has reduced Big Creek basin capacity from 2,754 acre-feet (ac-ft) in 1922 to 1,512 ac-ft in 2001. The 2001 basin capacity was 54.9 percent of the 1922 potential basin capacity. For water-supply purposes, these volumes convert to capacities of 897 million gallons in 1922 and 493 million gallons in 2001. Sedimentation rate analyses indicate a decline in annual sediment deposition rates from 28 ac-ft (1922-1946) to 9.9 ac-ft annually (1983-2001). The long-term average annual deposition rate was 15.7 ac-ft (1922-2001). Sedimentation has reduced the Sand Creek basin capacity from 610 acre-feet (ac-ft) in 1922 to 246 ac-ft in 2001. The 2001 basin capacity was 40.3 percent of the 1922 potential basin capacity. For water-supply purposes, these volumes convert to capacities of 199 million gallons in 1922 and 80 million gallons in 2001. Sedimentation rate analyses indicate a decline in annual sediment deposition rates from 8.4 ac-ft (1922-1946) to 2.3 ac-ft annually (1983-2001). The long-term average annual deposition rate was 4.6 ac-ft (1922-2001). | | | | Date Created: | 9 24 2004 | | | | Agency ID: | CR-2002-09 | | | | ISL ID: | 000000000870 Original UID: 999999994347 FIRST WORD: Sedimentation | |
| 838: | | Title: | | | | | Volume/Number: | 2002 | | | | Issuing Agency: | | | | | Description: | The hydrologic regime of a natural stream is usually highly complex and encompasses a wide range of discharges. The magnitudes and frequencies at which the various discharges occur play a key role in creating the channel's morphology. The concept of 'dominant discharge' proposes that there exists a single steady discharge that, theoretically, if constantly maintained in a stream over a long period of time would form and maintain the same basic stable channel dimensions as those produced by the long-term natural hydrograph. This theoretical discharge is referred to as a stream's dominant discharge. If such a dominant discharge exists and can be accurately calculated, this discharge can be one of the tools that stream restoration personnel use to help design channels that are morphologically stable, i.e., not experiencing either excessive erosion or sediment deposition. There is no direct method to calculate a stream's dominant discharge, and stream researchers have commonly assumed that the dominant discharge can be equated with either the stream's bankfull discharge, a specific flood recurrence interval, or the stream's effective discharge. The purpose of this study is to analyze the available data and existing computational methods for the third approach, that being the estimation of effective discharges specific to Illinois streams. The effective discharge of a stream is defined as the single discharge rate that carries the most sediment over time. Note that the effective discharge is not typically a discharge associated with the most extreme flood events, which may carry large amounts of sediment load but occur infrequently. Instead it is commonly considered to be a moderately high discharge having a more modest load, but occurring frequently enough that in the long-run it carries more sediment than the extreme flood events. To facilitate computations, the effective discharge is estimated as occurring within a discharge class or increment, rather than as a single discharge. Effective discharge can be estimated using data on suspended sediment load, bed load, bed material, or total sediment load, with the method of estimation depending on the sediment transport characteristics of the stream, available data, and, to some degree, the researcher's school of thought. For this study, estimates of effective discharges are based on the suspended sediment load, which is the dominant load in most Illinois streams. Suspended sediment data collected at 88 gaging stations within Illinois were analyzed to determine which gaging stations in Illinois currently have sufficient suspended sediment data available to estimate effective discharges. A procedure was adapted from previous research and implemented to compute effective discharge values for each stream location having sufficient suspended sediment data. For each of those gaging stations, an estimate was made of the flow frequency at which the effective discharge was equaled or exceeded. For stations having adequate sediment data, flood recurrence intervals associated with effective discharge values were computed using annual maximum flow data. Correlation coefficients (r2) for 12 linear regressions are presented to describe the relationship between six effective discharge parameters and channel slope and watershed area. The data from 20 of the 88 gaging stations were deemed sufficient for computing effective discharge values. These 20 gaging stations were located on streams with watershed areas ranging from 244 to 6363 square miles (mi2). The relatively large watershed areas allow use of mean daily discharge values in computing effective discharge values. The annual maximum series analysis indicated that recurrence intervals associated with effective discharges found at these stations ranged from less than 1.01 years to 1.23 years. Such recurrence intervals are on the low end of the 1- to 3-year recurrence intervals commonly reported in other studies. However, these recurrence intervals are representative of Illinois' larger watersheds, and recurrence intervals of effective discharges in smaller Illinois watersheds could be quite different. Of the 20 qualified stations, 20 percent had effective discharge estimates that were less than the station's average mean daily discharge. Such low magnitude flow events are not usually associated with a stream's dominant discharge. Thus, geomorphic assessments and bankfull computations are required to further assess whether these and other effective discharge values are representative of the 20 individual streams' dominant discharges. Due to the small sample size, regression analyses relating specific effective discharge parameters to channel slope and watershed area were inconclusive. Effective discharge computations are particularly sensitive to how the sediment rating curve used in the computation is developed and the number of discharge classes used in the computation. The sampling frequency and duration over which the sediment samples used to create sediment rating curves also may influence effective discharge computations significantly. Thus, while stream restoration personnel will likely continue to use these and other effective discharge values as part of several tools in hydraulic and channel design applications, uncertainties in their use should be acknowledged and undue weight should not be assigned these values, as they cannot yet be expected to yield fully reliable results in applications. Like previous researchers, we recommend more comprehensive investigations that compare effective discharge estimates to bankfull discharges in combination with a geomorphic assessment of each stream's characteristics to yield a better understanding of whether currently computed effective discharge values adequately represent dominant discharges in Illinois. Suspended sediment represents the dominant sediment load in most Illinois streams. In some cases, effective discharge computations based on total loads or bed material loads may be more appropriate than using suspended sediment loads analyzed here. However, the bed load, bed material, bank material, local channel slope, and channel cross-section information required to perform these computations and analyses are almost nonexistent. While many of these data can be collected at selected stream locations, inherent difficulties in estimating bed loads in Illinois streams make this approach unfeasible. New technologies for sampling or estimating bed load most likely would need to be developed and tested. This analysis presents a comprehensive assessment of effective discharges based on the available suspended sediment and flow data in Illinois. Long-term sediment data sets are needed at more stream locations to more fully estimate and understand effective and dominant discharges in Illinois streams. The greatest need for additional data is for smaller watersheds less than approximately 200 mi2 because most potential applications of the effective discharge concept in stable channel design are for smaller watersheds. Smaller watersheds also may have significantly different geomorphic characteristics and effective discharges may behave differently than those in larger watersheds. The Illinois State Water Survey currently is measuring suspended sediment at gaging stations on 13 small watersheds, which could prove very useful in effective discharge analysis as longer data records become available at these sites. | | | | Date Created: | 9 24 2004 | | | | Agency ID: | CR-2002-10 | | | | ISL ID: | 000000000871 Original UID: 999999994348 FIRST WORD: Effective | |
| 839: | | Title: | | | | | Volume/Number: | 2003 | | | | Issuing Agency: | | | | | Description: | The Illinois Streamflow Gaging Network has been operated by the U.S. Geological Survey (USGS) since the early 1900s. From its inception, the operation of the network has been maintained through a cooperative partnership between the USGS and state and federal agencies. Hydrologic information provided by the network is vital for the general management of Illinois' water resources. Streamflow data are continually used for forecasting floods and droughts; assessing the biological and chemical health of our streams; operating reservoirs, water supply facilities, wastewater treatment facilities, and hydroelectric plants; assessing and predicting the long-term impacts of climate and land-use trends on our streams; and numerous other important uses. The purpose of this study was to conduct a comprehensive evaluation of the use of Illinois streamflow data, with the goal that this information and analysis will be used by the network's cooperating agencies and others for current and future decisions related to funding and content of the network. Evaluations such as this have been conducted in the past, and should continue to be conducted periodically to assess whether the network meets the data needs of users in an effective manner, to assess emerging needs, and to anticipate needed programmatic changes to the network. This report identifies several emerging applications for which more and additional types of stream data likely will be needed, including applications related to stream and watershed restoration and water quality load assessment. However, in general, it is not possible to anticipate many of the future needs of the streamflow gaging program. More often than not, emerging issues will need to use streamflow data far before there is sufficient time to collect data for that specific use. The only way to have adequate data when these needs arise is to maintain a base network at locations that are representative of the streams of Illinois, such that these long-term data are available to meet a broad range of potential needs. This base network of gaging stations also is needed to provide general streamflow information for ungaged streams throughout Illinois. There are thousands of streams in Illinois, whereas the network currently includes roughly 160 continuous-streamflow gages on fewer than 110 of these streams. For other streams, flow characteristics must be estimated from the available gaging records using regional hydrologic principles. Various methods are available to evaluate the effectiveness of specific gaging records for use in this regional transfer of information. This report includes several descriptive measures of the regional value of gage information and also summarizes a numerical evaluation based on information transfer theory. No single approach can effectively describe the broad range of considerations needed to evaluate the regional value of gages. However, it is clear that applications in regional hydrology will need additional data beyond those which are currently supported by the network. Specifically, the base network is noticeably lacking data from small watersheds in rural Illinois. In addition, several hydrologic regions in Illinois have a limited number of gages for use in regional analysis. Two questionnaires were developed to ascertain the importance and uses of the data from the streamflow gaging network. The first questionnaire was distributed to all agencies that provide cooperative funding to the network. The second questionnaire was developed on an Internet Web site to be accessed and filled out by all interested users of Illinois streamflow data. In both questionnaires, the respondents were asked to identify: 1) the types of data that they most frequently use and/or are most critical for their needs; 2) categories of data applications and their relative importance; and 3) the importance of specific gages for their applications. The report provides a ranking of the relative importance of individual gages based on the responses from the questionnaires. The users indicate that river forecasting/flood warning is the overall most important category of application of streamflow data, followed by long-term flow statistics for analyzing hydrologic trends and determining human impacts to streams. However, the majority of users are more likely to use streamflow data for individual project needs such as those related to hydrologic-hydraulic modeling and design, and biological and conservation assessment. Analysis of gaging records indicates that streamflow conditions are not stationary, and vary not only from year to year but also from decade to decade as influenced by climate variability and other factors. More than half of the long-term flow records in rural areas show statistically significant increases in average and low-flow conditions that appear to occur as a result of climate variability. Statewide, over the past 25 years, there has also been an average increase of 18 percent in the estimates of the 100-year flood peak discharge as represented by long-term records. With the decline in the number of crest-stage peak-flow gages and small watershed gages, many of the records available for certain types of hydrologic analysis are older, discontinued gaging records that may not accurately represent the expected present-day, long-term hydrologic conditions. Shorter gaging records, regardless of period of record, also may not fully represent the expected long-term conditions. There is a need for analytical techniques to assess inherent differences in streamflow records and characteristics such as flood frequency that are caused by climatic variability and other factors. The network appears to be meeting most traditional current-use needs. However, there is a need to reinforce the base network, specifically regarding data for relatively small rural watersheds that are needed to address various emerging issues, long-term regional assessment, and peak flood estimation. The size of the overall network would have to be increased an additional 15-20 percent to more effectively address data needs related to small to medium-sized rural watersheds. Also, there is a growing need for new types of stream data to address specific biological and conservation issues such as stream and watershed restoration. This report only addresses streamgaging issues related to flow quantity, and thus there are no conclusions or recommendations related to water quality, precipitation, or other types of hydrologic data. Funding for the Illinois Streamflow Gaging Network is subject to uncertainties, and this is especially the case regarding potential growth or changes to the network. The National Streamflow Information Program (NSIP), initiated by the USGS in 1999, proposed that the USGS eventually would assume the costs of gages that directly meet specific federal interests. However, it is uncertain whether this or other initiatives from traditional funding sources will produce a prominent change in the size and character of the network. More likely, gaging needs for emerging issues will need to be funded from new sources currently not participating in the network. By its nature, it is essential that the base network be funded mainly through state or federal agencies with a long-term commitment to the streamflow gaging program. | | | | Date Created: | 9 24 2004 | | | | Agency ID: | CR-2003-05 | | | | ISL ID: | 000000000872 Original UID: 999999994401 FIRST WORD: Evaluation | |
| 840: | | Title: | | | | | Volume/Number: | 2003 | | | | Issuing Agency: | | | | | Description: | The Vermilion River and Little Vermilion River watersheds lie in seven counties in east-central Illinois and west-central Indiana. The drainage areas of the Vermilion River and Little Vermilion River at their confluences with the Wabash River are 1434 and 244 square miles, respectively. The Vermilion River meets the Wabash River at river mile 257.4 and has three tributaries: North Fork, Middle Fork, and Salt Fork. The Little Vermilion River is a direct tributary of the Wabash River at river mile 247.8. Lake Vermilion, a 660-acre impounded reservoir located on the North Fork Vermilion River, is the main municipal drinking water supply for the City of Danville, Illinois. The Little Vermilion River is the main tributary for the 63-acre Georgetown Reservoir, the municipal drinking water supply for the community of Georgetown, Illinois. Approximately 88 percent of the watersheds for both rivers are in agricultural production with approximately 5 percent in forest/woodlands and wetlands. The Illinois State Water Survey (ISWS) conducted a two-year watershed monitoring study of the Vermilion River and Little Vermilion River watersheds for the Vermilion River Ecosystem Partnership-Conservation 2000 Ecosystem Program. The purpose was to assist the partnership by establishing a baseline of hydrologic and water quality data to provide a better understanding of the cumulative impacts of future best management practices implemented in the watersheds. The ISWS established a streamgaging station on the Little Vermilion River near Sidell and monitored the hydrology, sediment, and nitrate-nitrogen (nitrate-N) there and at three U.S. Geological Survey (USGS) streamgaging sites in the Vermilion River watershed (Middle Fork Vermilion River above Oakwood, North Fork Vermilion River near Bismarck, and Vermilion River near Danville). Annual sediment loads for the three Vermilion River watershed stations were approximately three times higher than loads at the Little Vermilion station. The Middle Fork station had the highest sediment loads among the three Vermilion River stations for both project years. The North Fork station had the highest annual nitrate-N load for both monitoring years. In general, annual sediment and nitrate-N loads were lower during the first monitoring year, due to below average spring season runoff. Sampling for three pesticides (atrazine, alachlor, and metolachlor) was done on a weekly basis from June to October 2002. Atrazine was the only pesticide detected during this period. The highest level sampled was 20.93 micrograms per liter (and#956;g/L) and, and all others were below 2.65 and#956;g/L. | | | | Date Created: | 9 24 2004 | | | | Agency ID: | CR-2003-06 | | | | ISL ID: | 000000000873 Original UID: 999999994403 FIRST WORD: Sediment | |
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