Assessing the Environmental Condition of

Sinkholes in the Jacks Fork Watershed

 

EPA-R7WWPD-04-009

EPA Water Quality Cooperative Agreement

 

 

Submitted to:

Top of the Ozarks Resource Conservation & Development, Inc.

6726D Highway 63

Houston, MO 65483

 

April, 2006

 

Scott Consulting Engineers, P.C.

550 E. St. Louis Street

Springfield, Missouri 65806

417-866-8644 FAX 417-866-3035

www.scotteng.com

sce p.n. 104168.00

 

 

 

Table of Contents

Section Page

Executive Summary i

I. Introduction and Description of Environmental Issue of Concern 1

a. Purpose of Assessment 1

b. Project Goal and Objectives 2

c. Application of GPS Mapping and GIS, Project Area Geology

and Landowner Types 3

d. Application of Dye Tracing 5

II. Mapping and GIS 6

a. Summary of Procedures and Techniques 6

b. GIS Data Acquisition and Development 9

c. Environmental Assessment of Sinkholes Investigated 15

III. Dye Tracing 16

a. Sinkhole Selection 16

b. Summary of Procedures and Techniques 17

c. Dye Tracing Results 17

IV. Summary and Recommendations 22

 

 

LIST OF TABLES

TABLE TITLE PAGE

1 Summary of Dye Trace Lengths, Gradients, and Estimated Mean Velocities for the First Arrival of Tracer Dyes 19

2 Summary of the Performance of Sinkholes Recharging the Ozark Aquifer 20

 

LIST OF FIGURES

FIGURE TITLE PAGE

1 Location of the Study Area 1

2 Bedrock Geology in the Study Area 4

3 Location of Sinkholes Mapped 12

4 Groundwater Tracing Summary 19

 

Appendix A Sample Sinkhole Data Collection Form

Appendix B GIS Metadata Files

Appendix C OUL Dye Tracing Report

 

EXECUTIVE SUMMARY

A recent assessment of the Jacks Fork River conducted by the U.S. Geological Survey and the National Park Service shows that levels of fecal coliform bacteria in the river are exceeding the State's standard of 200 bacterial colonies per 100 milliliters of water for safe whole-body contact recreation. As an Outstanding Natural Resource Water, no degradation of water quality in the Jacks Fork is allowed per Missouri’s Water Quality Standards. As an initial step in developing a watershed management plan to address the impairment of the Jacks Fork River, this project provides the Jacks Fork Watershed Committee with a geographic information system (GIS) that includes an inventory and environmental assessment of 300 sinkholes in and around the Jacks Fork watershed. Through dye tracing, this project also delineates the general direction of groundwater flow and identifies areas of recharge for the springs along the Jacks Fork River.

One hundred and ninety-five (195) sinkholes were investigated within the Jacks Fork topographic watershed and an additional one hundred and five (105) were investigated along the perimeter of the watershed. Each sinkhole investigated was evaluated as to the degree of potential negative environmental impact due to site conditions and was then categorized according to the environmental action recommended – immediate, short-term, long-term, or no action needed.

Of the 300 sinkholes investigated, approximately 287 of the sinkholes are assessed as requiring no action due to a lack of any apparent negative threats to the Jacks Fork River. The remaining 13 sinkholes should be addressed with long-term actions such as distribution of general public brochures and information packets that summarize the potential threat sinkholes can pose to groundwater and surface waters. These sinkholes showed accumulation of trash and other waste materials throughout the decades, mostly inorganic in nature such as appliance, tires and fencing material, which could demonstrate to future patrons that the area has long been accepted as a dumping site.

To complement the sinkhole inventory database and environmental assessments, five (5) dye traces were performed by Ozark Underground Laboratory (OUL). Two previous traces that demonstrated flow paths to the Jacks Fork River were included for completeness. Four of the seven traces included in this report were started outside the Jacks Fork topographic watershed, yet all dye traces were detected within the Jacks Fork watershed. The demonstrated interbasin transfer of water is all discharged from Alley Spring. This additional area adds approximately 25% more land to the topographic watershed of the Jacks Fork River above Eminence.

The travel times determined in this investigation for water passing through the sinkholes were somewhat shorter than survival times of fecal coliform bacteria in karst groundwater systems. If significant bacteria sources were present in sinkholes when a runoff event took place, bacteria could survive long enough to be discharged in the Jacks Fork River.

While this project did not reveal any situations that showed evidence of on-going bacteriological contamination, the data collected were used to establish a sinkhole inventory database and associated GIS that can be incorporated into a watershed management plan. Not every sinkhole in the Jacks Fork watershed was mapped and subsequently assessed. Based on the percentage of landowners who refused access to their property, there may be sinkholes in the watershed that can transport bacteriological contamination that could reach the Jacks Fork River under certain runoff and groundwater flow conditions. The Jacks Fork Watershed Committee should continue to work with local stakeholders to increase awareness of the issues contributing to the impairment of the Jacks Fork River.

  1. Introduction and Description of Environmental Issue of Concern
    1. Purpose of Assessment
    2. As an initial step in developing a watershed management plan for the Jacks Fork watershed, this project provides a geographic information system (GIS) that assesses the environmental condition of sinkholes in and around the Jacks Fork watershed. This project also delineates the general direction of groundwater flow and identifies areas of recharge for the springs along the Jacks Fork River. The study area and topographic watershed boundary are shown in Figure 1.

      The Jacks Fork River is classified as an "Outstanding Natural Resource Water" that must be protected to maintain safe whole-body contact. A recent assessment of the Jacks Fork River conducted by the U.S. Geological Survey and the National Park Service shows that levels of fecal coliform bacteria in the river are exceeding the State's standard of 200 bacterial colonies per 100 milliliters of water for safe whole-body contact recreation. As an Outstanding Natural Resource Water, no degradation of water quality is allowed per Missouri’s Water Quality Standards. This means that the fecal coliform concentration that is naturally present in the river establishes the "natural background" and is therefore the standard concentration for this water body.

      To address the bacteria issue, the Missouri Department of Natural Resources (MoDNR) conducted a study to establish a Total Maximum Daily Load (TMDL) for fecal coliform in the Jacks Fork River. A copy of MoDNR’s TMDL study can be found at:
      www.epa.gov/region07/water/pdf/jacksfork_riverfinaltmdl.pdf .

      The TMDL study provides a summary of the area history, land use, geological conditions, and water quality problems associated with the Jacks Fork watershed, as well as how the TMDL was determined for the Jacks Fork River. MoDNR then held a series of public meetings to inform local residents of the results of the TMDL study and encouraged the formation of a watershed partnership for local decision making and watershed management.

      As a result MoDNR’s public meetings, a group of approximately 30 local business representatives and landowners volunteered to form the Jacks Fork Watershed Committee. The Committee plans to address the water quality issue through grant-funded studies and programs that will promote common sense management practices and aid individual voluntary actions that will avert direct intervention by state and federal agencies. The Committee’s goal is to develop a watershed management plan that is based on local cooperation to educate, preserve, protect and promote water quality and recreational use of the Jacks Fork River and its watershed.

      The Jacks Fork watershed consists of karst terrain and features, such as losing streams and sinkholes, which influence the movement and potential contamination of both surface water and groundwater. The motivation for this project is to determine if sinkholes can be considered a major contributor of bacteriological pollution in the Jacks Fork River. Sinkholes can provide a pathway for pollutants to reach the groundwater and eventually surface waters such as the Jacks Fork by receiving the pollution directly from overland runoff or subsurface percolation.

      As an initial step, the Committee is working with Top of the Ozarks Resource Conservation and Development and Scott Consulting Engineers to map sinkholes in and around the Jacks Fork watershed. This project provides a GIS that identifies and assesses the environmental condition of sinkholes in and around the Jacks Fork watershed. This project also delineates the general direction of groundwater flow and identifies areas of recharge for the springs along the Jacks Fork River. The project is motivated by the Jacks Fork Watershed Steering Committee, which has expressed concern about the impact of sinkholes on the environment of the watershed.

    3. Project Goal and Objectives

The goal of this project is to provide Top of the Ozarks RC&D (RC&D) with a digital database of sinkhole information that will serve as a sinkhole inventory for the Jacks Fork watershed as well as conduct up to five (5) dye traces to determine the general direction of groundwater flow and areas of recharge for the springs along the Jacks Fork River. The data collected was compiled into a GIS and the following report provides an assessment of the data, complete with ranked evaluations of the sinkholes investigated and recommended actions. The report is reviewed by the USEPA. The objectives for completing this project include:

    1. The project required digital data from various agencies to be compiled into an initial GIS which was used to identify sinkhole locations and guide field investigations. Up to 300 sinkholes were investigated. Each sinkhole investigated was evaluated as to the degree of potential negative environmental impact due to site conditions and ranked according to the environmental action recommended: immediate, short-term, long-term, or no action needed.
    2. Dye traces were conducted from five (5) sites (sinkholes) to identify areas of recharge for the springs along the Jacks Fork River. The dye traces were performed by Ozark Underground Laboratory (OUL) and the results were used to refine the conclusions from previous studies concerning the relationship between sinkholes and surface waters in the Jacks Fork Watershed.
    3. For all sinkhole site investigations, the landowner was contacted ahead of time to receive permission to access their property. Sinkholes on both private and public land were investigated. GPS coordinates, photographs, sketch maps, and descriptive attributes of each sinkhole investigated were compiled in electronic form and added to the GIS.
    4. Prior to submitting the report to the USEPA, a public meeting will be held to present the maps, rankings, and recommendations. Responses from landowners will be solicited.

    1. Application of GPS Mapping and GIS, Project Area Geology and Landowner Types
    2. Creating a sinkhole inventory database for the Jacks Fork watershed was a major focus of this project. Three hundred (300) sinkholes were visited and mapped in and around the Jacks Fork watershed using global positioning system (GPS) equipment. The resulting database, once integrated with the initial GIS, provides a map that shows the quantity and proximity of sinkholes to the Jacks Fork River. The mapping visits also permitted the sinkholes to be evaluated and ranked to determine the degree of environmental threat associated with site conditions. Thus, GPS mapping and integration into a GIS was an applicable procedure for accomplishing the goal of this project. Section II of this report summarizes the mapping and GIS procedures and references the GIS Quality Assurance Project Plan (QAPP) that served as the basis for the procedures.

      The area for this project includes all of the Jacks Fork Watershed as well as sinkholes along the perimeter of the watershed. The goal of the project was to map 200 sinkholes located in the Jacks Fork Watershed and 100 sinkholes located along the perimeter of the watershed. As mentioned above, the terrain of the watershed is karst, consisting heavily of limestone with great relief, losing streams, caves, springs, and, of course, sinkholes. A combination of both pastureland/cropland and forest/woodland cover exists throughout the region. Sinkholes were observed in both land types.

      The rock formations encountered in this study include the Ordovician age Jefferson City, Cotter, Roubidoux, and Gasconade formations, as well as the Cambrian Eminence and Potosi Formations. There are also isolated patches of Precambrian volcanic rocks exposed in the easternmost portion of the study area.

      All of the formations encountered in the study, with the exception of the Precambrian volcanics, have been extensively karstified and are part of a single hydrogeologic unit called the Ozark Aquifer. Karstification denotes extensive weathering of the bedrock that allows appreciable movement of surface-derived water into and through the groundwater system by means of the dissolved openings in the bedrock. Most of the aquifer recharge in this part of the Ozarks is through losing stream channels, although sinkholes direct their runoff into the groundwater system as well. Figure 2 shows the bedrock geology of the study area.

      Permission was requested from landowners where sinkholes were anticipated. Potential sinkholes were identified using USGS topographic quadrangle maps, digital relief maps, and, to a lesser extent, aerial photos. Some sinkholes were discovered while traversing to map anticipated sinkholes, and some were identified by landowners who knew of additional sinkholes in the area. Potential sinkholes were identified on land owned by private individuals, businesses, the Missouri state government, and the federal government. Land owned by the Missouri state government included State Park land and Department of Conservation land. Land owned by the federal government included National Park Service land (including Ozark National Scenic Riverways) and National Forest Service land. All government agencies cooperated with our efforts on this project.

    3. Application of Dye Tracing

To complement the sinkhole inventory database, five (5) dye traces were performed by OUL to determine the general direction of groundwater flow and to identify areas of recharge for the springs along the Jacks Fork River. The dye traces can provide evidence of a hydrologic connection between sinkholes (dye introduction points) and locations leading to or along the Jacks Fork River (dye sampling stations). The dye traces were applicable to this project by simulating how a pollutant entering a sinkhole in the Jacks Fork watershed can be carried by groundwater and subsequently discharged at distant locations, such as springs along the Jacks Fork River, potentially contaminating the river.

For the dye tracing to be successful, both the dye introduction points (sinkholes) and the dye sampling stations (locations along the river) needed to be carefully selected to achieve meaningful results. Accordingly, the general location of sinkholes traced was chosen to distinguish areas of recharge for major springs discharging to the Jacks Fork River. The sinkholes selected also needed to be considered a high-ranking threat for contamination of the Jacks Fork. While there were no sinkholes investigated that were obvious high-ranking threats for contamination, readily accessible sinkholes were chosen that were representative of sinkhole performance in the study area.

The selection of sinkholes to trace also depended on obtaining landowner permission to not only access the sinkhole but to introduce dye into the sinkhole. To facilitate the dye introduction, large quantities of water (at least 3,000 gallons) were used to flush the dye into the groundwater system through the sinkholes selected. Consequently, sinkholes located near ponds were better candidates for tracing, as water could be pumped out of the pond to help introduce the dye into the groundwater system. At the time the first round of dye traces were introduced, the area was experiencing drought conditions. Consequently, the groundwater velocities were appreciably lower than under baseflow or higher groundwater conditions. Section III of this report further summarizes the dye tracing procedures and references the Dye Tracing Quality Assurance Project Plan (QAPP) that served as the basis for the procedures.

  1. Mapping and GIS
    1. Summary of Procedures and Techniques

The first steps of the mapping and GIS portion of this project include compiling existing maps, or base data, of the area to identify sinkholes to investigate and sending out letters to landowners requesting permission to access their property. The study area for this portion of the project includes all of the Jacks Fork topographic watershed as well as sinkholes along the perimeter of the watershed. The goal of this portion of the project was to map 200 sinkholes located in the Jacks Fork Watershed and 100 sinkholes located along the perimeter of the watershed.

Permission was requested from landowners via a letter that explained the motivation for our project and what actions we wanted to perform on their land. Approximately 240 letters were mailed out, with about 75 of the letters returned with a reply. Of the replies received, approximately 44 landowners gave permission and 31 rejected our request. As a result of the relatively low number of private landowners who granted permission to access property, many of the sinkholes mapped were on government-owned land. Of the 300 sinkholes investigated, 122 were on government property while the remaining 178 were on private land.

The base data for the GIS is formed by aerial imagery, topographic contours, county boundaries, topographic quadrangle boundaries, and public land survey section lines. The data is derived from government data that meets the National Map Accuracy Standards for 1:24000 scale maps. The 1:24000 scale standard specifies that 90 percent of well-defined features are to be within 40 feet of the true mapped ground position.

The GIS includes a shaded relief surface and a color elevation surface for easy visualization of the land surface. The surfaces are generated from a digital elevation model (DEM) that consists of a grid of elevation values spaced at 10-foot intervals. The elevation values are interpolated from the topographic contours and conform to the 1:24000 scale accuracy.

The watershed boundaries are also derived from the topographic contours and conform to the associated 1:24000 scale accuracy.

The stream centerline data is derived from the 1:100,000 scale USGS National Hydrography Dataset (NHD). The lines are adjusted to match the streams shown on the aerial imagery and thereby conform to the 1:24000 scale accuracy of the project. The data set contains the original NHD attribute data except for the stream segment lengths. The segment lengths are revised to match the stream line adjustments.

Additional data provided with the GIS includes road centerlines, municipal, boundaries, named geographic point locations, springs, USGS stream gauges, NPDES discharge points, state and federal land boundaries, geologic data, and previously identified sinkhole point locations. The data is provided as supplemental data that is derived from data sets produced at various scales of locational accuracy.

The field data developed for this project is presented in digital form as data layers and linked reports within a geographic information system (GIS). The field data consists of 300 sinkhole evaluations and maps generated through field surveys using global positioning system (GPS) equipment. Data generated by dye traces from selected sinkholes to springs on the Jacks Fork River is also presented in the GIS.

The field data reports, GIS data files, and GIS project files are provided on a DVD disk that accompanies this report. The GIS vector data is provided in Environmental Systems Research Institute (ESRI) shapefile format and the image data is provided in ERMappper ECW compressed image format. The data is compiled in GIS project files for ESRI ArcView software.

The GIS project file is provided in the ArcView directory on the DVD and is named "Jacks_Fork_Sinkholes.apr". An executable file for installing a plugin to view the compressed ECW imagery is provided in the folder named ERMapper plugin for AV3.x. This plugin must be installed for the image layers to be viewed in ArcView.

The GIS data files are provided in the GIS_Data directory on the DVD. The sinkhole data is provided as a file named "sinkhole_inventory.shp". A file containing the photograph names associated with each sinkhole is provided as a file named "sinkhole_photographs.shp". The dye trace data is provided in four files named "historic Alley Spring Traces.shp", "state plane dye.shp", "stations-state plane.shp", and "state plane trace.shp".

The sinkhole data generated from the GPS field surveys is also presented as individual reports for each sinkhole. The sinkhole reports include all of the data collected on the location, size, shape, and condition of the sinkholes. Each report includes a sketch map illustrating the shape and significant features of the sinkhole. Photographs are also included. The sinkhole reports are provided in digital form as HTML files on the DVD. The sinkhole sketch maps and sinkhole photographs included in the HTML sinkhole reports are provided in JPEG format in the sketches and photos directories on the DVD. The sinkhole reports are provided in electronic form as part of this report.

The ArcView GIS project file included on the DVD includes a script for linking the digital HTML sinkhole reports to the points shown on the sinkhole GIS data layer. The reports are displayed by clicking on the sinkhole points using the hotlink tool included on the ArcView tool bar.

The field data is presented on a base map of geographic data that includes aerial photography, a shaded relief topographic surface, a color coded elevation surface, topographic contours, stream center lines, geographic boundary lines, and other supplementary data layers. The data layers may be displayed in various combinations as desired. The base map layers are derived from existing sources of geospatial data produced by various government agencies. The files for all of the base map layers are included in the GIS_Data directory on the DVD.

Mapping the karst conditions within the Jacks Forks River Watershed requires a level of detail that is shown on 1:24000 scale topographic maps; thus, the GIS data is provided at that scale. The data is projected to conform to the Missouri Central State Plane Coordinate System using units of US feet and the North American Datum of 1983 (NAD83). The GIS is provided in this projection since it is commonly used for local cadastral and 911 systems.

The GPS sinkhole coordinates represent the lowest point of the sinkholes or center of the sinkholes as well as could be determined. The GPS equipment used to determine the coordinates has an accuracy that is much higher than the accuracy required by the project. The attribute table associated with the sinkhole point data includes the latitude and longitude coordinates of the points in decimal degrees. The values are given to five decimal places, which is less than plus or minus 15 feet.

Descriptive data collected at the sinkhole locations is recorded on field data forms developed for this project. The data forms include sketches of the sinkholes that are drawn on a polar coordinate grid. The sketches are drawn at scales indicated on the grid for each location.

Data recorded at the site includes the sinkhole number, the date visited, the sketch map with associated annotations, the dimensions of the sinkhole, the apparent drainage ability, the floor characteristics, the landcover, photograph numbers, assessment recommendations, and remarks concerning significant features and environmental conditions. For drainage ability, the comment "no evidence of standing water" indicates that there are no apparent debris lines made by water ponding in the sinkhole. Information for assessing the environmental condition of the sinkholes is recorded as remarks and recommendations for maintenance, and is recorded as the assessment. The assessment is recommended for consideration concerning maintenance of the sinkhole.

Information obtained from data layers in the GIS and entered in the office includes all of the sinkhole location information, owner name and address, topographic setting, elevation range, and geology.

Data added by visual analysis of the sinkhole sketch maps includes the sinkhole shape and orientation. For the sinkhole shape, information about the sinkhole floor characteristics is combined with the perimeter shape to form combinations of the following terms:

Perimeter Shape: circular, elliptical, elongated, irregular

Floor Shape: bowl, funnel, pan, shaft

The combinations form classifications such as elliptical bowl, circular funnel, etc.

Sinks with an observable major axis or directional trend have the major axis drawn on the map with the azimuth direction indicated. The azimuth direction is included in the sinkhole data as the sinkhole orientation.

Information on the dye tracing portion of this project is included in the GIS as three shape files. The dye injection point file shows the injection location and includes data on the type of dye and the amount of dye injected. The sampling station point file shows the receiving station location and includes the name of the sampling station. The dye trace line file shows the straight-line paths of each dye from the injection point to the first detecting sampling station.

A supplemental file named "Historic Alley Spring Traces" is included to show the dye paths of two previous dye traces. Information on the dye tracing procedure and results is provided in Section III of this report.

  1. GIS Data Acquisition and Development
  2. Field Mapping System

    Sinkhole locations were mapped with a Trimble AG132 submeter differential GPS receiver. The receiver uses the US Coast Guard radio beacon network for real time differential correction. The system has a capability of locating features within one (1) meter of their true geographic position. The precision of the measurements is far greater than the 1:24000 scale map accuracy that is required by the project. The equipment is checked periodically against established benchmarks near Springfield, Missouri to insure accuracy. No instrument adjustments were made during the project.

    The GPS receiver connects to a Compaq iPAQ model H3995 pocket PC. The GPS signals are displayed, analyzed, and recorded on the pocket PC with Tripod Data Systems Solo Field data collection software. The software allows the GPS satellite position data (PDOPs) and the differential correction signal to be monitored continuously. All GPS measurements taken in the field were recorded with a PDOP of less than 4.

    The Solo Field software provides a screen display of the GIS base data and allows acquired GPS data points to be checked and validated against features that are visible on the screen. This capability allows the positional accuracy of the received GPS data and the features shown on the base layers to be continuously correlated during the field data collection process. Visible targets and features shown on base topographic and aerial image data layers were identified and checked against GPS measurements each day during the mapping process. No positional errors were detected against targets visible in the GIS display and no instrument adjustments were made during the project.

    The GPS mapping system uses 12 volt batteries that are capable of supplying power for a full day. Two extra batteries were carried for backup during the field mapping and all batteries were recharged every night.

    Field Mapping Procedure

    GIS data layers were loaded into the mapping system software and into ArcView software on a laptop computer prior to field mapping operations. The GIS data included USGS digital raster graphic topographic data (DRGs), USGS digital orthophotoquads (DOQs), sinkhole polygons, and other road, city, and boundary data. Land ownership layers were also loaded into the ArcView software on the laptop. Sinkhole polygons were selected as targets and checked against the land ownership data in ArcView to determine if permission was granted for mapping.

    A Garmin GPS 60 handheld GPS receiver was used for navigation while driving to the selected sites. The receiver signal was fed into the laptop and displayed using OziExplorer navigation software. After driving to the sinkhole areas, the sinkholes were accessed on foot or with the use of an ATV. The GPS/GIS mapping system was used to navigate to the individual sinkholes.

    The sinkholes were investigated initially with a preliminary walk-through survey to identify the sinkhole rim, the sinkhole eye, and other significant features. Sinkhole numbers and GPS locations were then logged into the Solo Field software. The sinkhole eyes were recorded as the sinkhole GPS positions. The sinkhole eyes were identified as depressions, mud-holes, openings, or the lowest points in the sinkholes.

    The dates of the mapping and the sinkhole ID numbers were recorded on the sinkhole data sheets developed for the project. The data sheets were used in the field to make sinkhole sketch maps with notes. The data sheets include a polar graph that was used to plot points measured during the field survey.

    Descriptions of sinkhole characteristics were entered in all weather field notebooks. The information recorded includes the date, a description of the sinkhole shape, the visually estimated depth, the land cover, floor characteristics and other remarks concerning the sinkhole conditions.

    Photographs of the sinkholes were taken with a digital camera. The photo numbers, photo locations, and photo look directions were recorded in the field notebooks.

    The sinkhole rims were mapped by one of the following three methods.

    1) Laser range finder:

    Distances from the eye to points on the sinkhole rim were made using a laser range finder. A Nikon Prostaff laser 440 laser range finder with a range of 400 meters and a half meter accuracy was used to make measurements. The field measurements were made in meters. The azimuths of the distance measurements were obtained with a hand compass.

    The measured distances and angles were used to plot points on the polar graph included on the sinkhole data sheets. The points defining the rim were plotted on the graph using a scale of 10 meters per ring. The data points were plotted to draw the sinkhole rims in the office later using AutoCAD. Notes related to the rims were added such as up-slope directions, down-slope directions, slope grades, high points and low points on the rim, and references to other significant features.

    2) GPS measurement:

    Where it was possible to walk or drive the ATV around the sinkhole rim, the rim perimeter was mapped with the GPS/GIS mapping system. The mapping system was set to take measurements at automatic intervals of 20 meters for big sinkholes, 10 meters for medium sized sinkholes, and 5 meters for small sinkholes. The rim perimeter was drawn automatically by the Solo Field software as the data was obtained and it was stored as polylines in the pocket PC data collector. Azimuths to significant features on the rim were made by hand compass from the sinkhole eye and notes of the features were made on the sinkhole data sheets. The notes and sinkhole polygons were combined later in the office using AutoCAD.

     

    3) DRG contour measurements:

    For very large sinks, USGS digital raster graphic (DRG) contours were used to represent the sinkhole perimeter. Significant features associated with the large sinkholes were located with the GPS/GIS field mapping system and recorded as the digital point data using the Solo Field software. The points were recorded with notes about the features and the associated sinkhole point numbers. The point data was combined with the sinkhole contours later in the office with AutoCAD.

    Data Transfer

     

    Field data stored in the pocket PC was digitally transferred to GIS computers in the office through connection methods provided by the equipment manufacturer. The data were transferred by the GPS surveyor who collected the data. The sinkhole GPS center points were transferred into ArcView and developed into an ESRI shapefile called sinkhole_inventory.shp. Figure 3 is a map of the study area showing the mapped sinkhole points and other locational information. As the Figure shows, a majority of the sinkholes mapped were between Summersville, Mountain View, and Alley Spring. This information is readily available in the GIS data associated with this project.

    The data recorded in the field notebooks was manually entered into data fields created for the sinkhole shapefile. Additional digital GPS data recorded for features associated with the sinkholes was transferred into AutoCAD so that it could be merged with field sketch map information. All the point data and the associated attributes were checked in ArcView for completeness and accuracy by the field surveyor.

    Photographs were downloaded to the office computers through connection methods provided by the equipment manufacturer. The files were initially stored with the sequential numbers assigned by the digital camera. The photographs were re-named to match photo numbers associated with the sinkhole point numbers. The file naming convention is in the form of photo_sink#_number, where sink# is the sinkhole point number and "number" is a sequential number where multiple photographs were taken of the same sinkhole.

     

     

    Sketch Map Development

    The sketch maps recorded on the sinkhole forms were scanned to electronic images at 100 dpi and imported into AutoCAD. The images were scaled to match the 10 meters per ring scale used for the polar graphs on the forms. The GPS sinkhole points were also imported into AutoCAD and the sinkhole forms were manually moved to the locations where the center point of the polar graph matched the imported GPS sinkhole center point. Points on the sinkhole rim that were plotted on the polar graphs by laser range finder measurements and compass azimuths were used to draw polylines for the rim in AutoCAD. The polylines were drawn through the points and were then splined by AutoCAD to form smooth polylines.

    USGS digital raster graphic (DRG) topographic map images and USGS digital orthophoto (DOQ) images were also imported and displayed as underlying images. The image layers were used to add large features. Features, such as roads, ponds, and tree lines were digitized from the underlying DRG and DOQ images.

    For sinkholes where rim polylines were generated in the field by automated GPS measurements, the polylines were imported into the AutoCAD drawing from the field mapping system. For very large sinkholes, the sinkhole rims were digitized from the contour lines shown on the DRG topographic images. Data points collected with notes in the field were used to make refinements in the shape.

    The map features developed from the plotted points and digitized lines were then printed from AutoCAD. The printed AutoCAD line drawings where placed on a light table and the lines representing the sinkhole rim and other digitized and plotted features were traced onto the original field data forms. The lines were drawn with symbols, including hatched lines for the sinkhole rims, dashed lines for drainages, and scalloped lines for tree lines. The positions of field notes were adjusted or leader lines were added to connect the notes to the AutoCAD generated features as necessary.

    Development of Attribute Data

    The major and minor axes directions of the sinkholes were determined from the rim polylines. The distances across the sinkholes along these axes were measured in AutoCAD. The areas within the rim lines were also calculated with AutoCAD. The sinkhole measurements were written onto the original sinkhole data forms as the measurements were made.

    Additional attribute data were generated by GIS analysis in ArcView. The sinkhole section, township, and range locations, the property owners, and the quadrangle locations were determined by displaying the sinkhole point data over the public land survey layer, property ownership layers, and the quadrangle boundary layers. The underlying geology was determined from the geology layer in the ArcView project. All of this information was written onto the original sinkhole data forms as it was determined during the GIS analysis.

    All other information recorded in the field notebooks was transferred to the field data forms. This includes the observed depths, floor characteristics, land cover vegetation, and other notes regarding the condition of the sinkholes and their associated features.

    The sketch maps for the sinkholes were analyzed for the sinkhole shape and orientation. For elongated sinkholes, an orientation line for the major axis was drawn on each sinkhole sketch map and the orientation azimuth was noted on the form and the drawing. The sinkhole perimeter shape was observed and combined with the reported floor shape to describe the overall 3-dimensional shape of the sinkhole. Descriptive terms were derived from combinations of the following terms:

    Perimeter Shape: circular, elliptical, elongated, irregular

    Floor Shape: bowl, funnel, pan, shaft

    Combinations of these terms were formed to make classification terms like elliptical bowl, circular funnel, etc. Acronyms for these terms were noted on the forms.

    All of the sinkhole attribute data written on the forms was manually entered into a database. The sinkhole ID numbers were then linked to the sinkhole shapefile for the GPS points and the file was exported to form the final sinkhole_inventory.shp data file.

    A separate database table was generated for the sinkhole images. The sinkhole image numbers were associated with the sinkhole photo files as described previously. The photo numbers were entered into the photo table. Notes from the field notebooks were manually entered into a database field in the image table.

    Generation of HTML Sinkhole Reports

    The sinkhole data is presented in its final form as sinkhole reports in HTML format. The reports include all of the sinkhole attribute information, the sinkhole sketch maps, and the associated photos. The HTML report pages are stored in a directory named sinkhole_reports on the DVD that accompanies this report. The file naming convention for the HTML files is in the form of sinkhole_sink#.htm, where sink# is the sinkhole point number.

    To generate the HTML report files, the final sketch maps on the sinkhole forms were scanned back into electronic form as JPEG image files and stored in a sketches directory within the sinkhole reports directory. The file naming convention for the sketch file is in the form of sketch_sink#.jpg, where sink# is the sinkhole point number. The image sizes were reduced by 80% so the image would fit well on a HTML page that can be displayed on a browser with a screen setting of 600 x 800 pixels.

    The sinkhole photographs were reduced to meet the same width as the sinkhole sketch map images and were stored in a photos directory under the sinkhole reports directory. The file naming convention is in the form of photo_sink#_number, where sink# is the sinkhole point number and "number" is a sequential number where multiple photographs were taken of the same sinkhole.

    The sinkhole reports where generated from the sinkhole database file. A Visual Basic program was developed to loop through the sinkhole inventory database file and extract the data into an HTML template. The program uses the sinkhole ID numbers to reference the sketch map image files and insert them into the pages. The program also loops through the photographs database to get the photograph numbers and associated remarks. The program inserts the sinkhole photographs into the page with overlying captions generated from the photo remarks field.

    The pages are laid out to include page breaks and page numbers so they may be printed out in hardcopy form. Conditions were specified in the HTML generation program to create appropriate page breaks for the various combinations of portrait and landscape photo sets.

    Geospatial Metadata

    The digital data associated with this project is accompanied by metadata that meets the content standards for geospatial metadata set forth by the Federal Graphic Data Committee. The metadata includes descriptions of data fields, data types, and coding schemes used in theme attribute tables. The metadata documents the processes involved in the production, manipulation, and modification of all data files included in the GIS project and it provides an accuracy assessment of each file. The metadata files for all the geospatial data produced and utilized for this project are included in the appendix of this report.

  3. Environmental Assessment of Sinkholes Investigated

The GIS and mapping portion of this project provides the Jacks Fork Watershed Committee with a geographic information system (GIS) that includes an inventory of sinkholes in and around the Jacks Fork watershed. One hundred and ninety-five (195) sinkholes were investigated within the Jacks Fork topographic watershed and an additional one hundred and five (105) were investigated along the perimeter of the watershed. Each sinkhole investigated was evaluated as to the degree of potential negative environmental impact due to site conditions and was then categorized according to the environmental action recommended – immediate, short-term, long-term, or no action needed.

Of the 300 sinkholes investigated, approximately 287 of the sinkholes are assessed as requiring no action due to a lack of any apparent negative threats to the Jacks Fork River. The remaining 13 sinkholes should be addressed with long-term actions such as distribution of general public brochures and information packets that summarize the potential threat sinkholes can pose to groundwater and surface waters. These sinkholes showed accumulation of trash and other waste materials throughout the decades, mostly inorganic in nature such as appliance, tires and fencing material, which could demonstrate to future patrons that the area has long been accepted as a dumping site. The watershed management plan should not permit such an attitude to perpetuate itself or encourage potential pollution in the future. The Committee may want to consider contacting these respective landowners directly to ensure each landowner is educated on the condition of the sinkhole on their property. Some of the landowners may be relatively recent owners of the property and are not fully aware of the potential pollution threats associated with sinkholes.

Approximately 38 of the sinkholes investigated showed evidence of ponding, either by containing standing water at the time of the visit or by exhibiting a debris line along the rim that is indicative of water ponding in the sinkhole. A common situation observed for the sinkholes with standing water is that they were once natural, shallow sinkholes that have been excavated to form a bigger pond. While this situation may provide a good enough seal to hold water at the present time, the long-term integrity of the pond is unknown. By disturbing the equilibrium associated with the original sinkhole, one could argue that the potential for further collapse of the disturbed sinkhole has increased. However, collapse events are probably infrequent enough to discard this situation as a potential contributor to the bacteriological pollution currently impairing the Jacks Fork River.

Additional long-term actions that can be incorporated into the watershed management plan include working with local counties to adopt construction guidelines that include erosion and sediment control. These guidelines would help protect area water resources from potential pollution resulting from erosion and transportation of sediment. Erosion and sediment control guidelines have been developed for many communities in the state and several examples exist that could be modified to meet the specific concerns associated with the Jacks Fork watershed.

  1. Dye Tracing
    1. Sinkhole Selection
    2. The study area for the dye tracing performed by OUL (shown in Figure 1) included both the Jacks Fork topographic watershed and those areas thought to contribute water to the Jacks Fork River via interbasin transfer of water along groundwater flow paths. Fieldwork was conducted to identify appropriate sinkholes for potential dye introductions. Next, a chosen tracer dye was introduced into the selected sinkholes. Springs, surface streams, and any other potentially relevant locations were then continuously sampled for the subsequent presence of the dye.

      As shown in Figure 3, a majority of the sinkholes mapped are located in the middle of the Jacks Fork watershed, between Summersville, Mountain View, and Alley Spring. While none of the sinkholes mapped showed evidence of being a high-ranking environmental threat, dye tracing sinkholes in the middle of the watershed will help determine the general direction of groundwater flow in the area as well as delineate the areas of recharge for the springs along the Jacks Fork River. Sinkholes that are significantly east of Highway 17 tend to drain to the Current River basin and thus would not produce data directly relevant to potential sources of adverse impact to water quality in the Jacks Fork River. For this project, the sinkholes of interest for dye tracing were those that had the potential to discharge water further upstream than Alley Spring. Accordingly, potential dye introduction locations in the middle of the watershed were evaluated for their utility in testing sinkhole hydraulic performance, their ability to characterize sinkholes in the watershed, and for accessibility to the sites.

      Three major springs along the Jacks Fork River are McCubbin Hollow Spring (about one mile southeast of the Highway 17 Bridge), Blue Spring (about one and one-half miles east of the Highway 17 Bridge north of Mountain View), and Alley Spring (just north of the Highway 106 Bridge and about four and one-half miles west of the Highway 19 Bridge north of Eminence), shown on Figure 4. Alley Spring is the largest spring in the watershed, with a mean discharge of approximately 80 million gallons per day. These three springs were important sites for dye monitoring because they are situated near the boundaries of the three sub-basins used by MoDNR to determine the TMDL. To determine the background fecal coliform level, MoDNR divided the watershed into three areas – the upper, middle, and lower sub-basins. The Upper Jacks Fork extends from the headwaters to the Highway 17 Bridge near Mountain View; the Middle Jacks Fork starts at the Highway 17 Bridge and extends to the Highway 19 Bridge near Eminence; the Lower Jacks Fork starts at the Highway 19 Bridge and ends at the confluence with the Current River. The Lower Jacks Fork is the impaired stream segment, approximately seven miles in length. The Middle and Upper Jacks Fork segments are not impaired and were used to determine background fecal coliform levels by MoDNR.

      Consequently, if the dye introduced into a sinkhole was detected at McCubbin Hollow Spring or Blue Spring, then pollution entering this sinkhole would potentially be able to contaminate the Middle Jacks Fork. Similarly, if dye were detected at Alley Spring, then pollution entering this sinkhole would potentially be able to contaminate the Lower Jacks Fork, which is the currently impaired segment of the river. However, any contaminants discharged from Alley Spring and impacting the Lower Jacks Fork would be detectable at the Highway 19 Bridge. In the TMDL document, MoDNR did not report unacceptable fecal coliform counts at the Highway 19 Bridge.

      To best utilize the significance of these three major springs, five sinkholes located in the middle of the watershed, including some outside of the topographic boundary, were selected for dye tracing. Dye monitoring at the three major springs, along with other monitoring stations, was useful in delineating the general direction of groundwater flow and identifying areas of recharge for the springs along the Jacks Fork River.

    3. Summary of Dye Tracing Procedures and Techniques
    4. Three different dyes were used for the groundwater tracing investigation – fluorescein, eosine, and rhodamine WT. All three of these dyes are environmentally safe and pose no risk to humans or to aquatic life in the concentrations used in professionally directed groundwater tracing work. Dye introductions were always made after sample collection and samplers were not handled again until clothing and field personnel had been decontaminated to prevent cross contamination and false positive results. Ten sampling stations were monitored for detection of the introduced dye.

      The complete OUL report, entitled "A Groundwater Tracing Investigation to Assess the Performance of Sinkholes in the Jacks Fork River Watershed", is presented as Appendix C in this report. Details on the procedures and criteria used in the dye tracing studies conducted by OUL are appended to the OUL report. These approaches were used throughout this study, and were detailed in the Quality Assurance Project Plan (QAPP) for dye tracing. There were no significant deviations from the QAPP.

      Dye quantities were selected based on the longest potential distance to detection locations (sampling stations) and previous tracing results. Dye was introduced into the groundwater system by either pumping water from a nearby pond or by hauling potable water to the site by truck.

      Notification of dye tracing was made to the Missouri Department of Natural Resources Geologic Survey and Resource Assessment Division. All sampling on National Park Service managed lands were done under permit. All dye introductions were made by an OUL Registered Water Tracer.

    5. Dye Tracing Results

Five groundwater traces were completed for this investigation. Two previous traces that demonstrated flow paths to the Jacks Fork River were included for completeness. Figure 4 summarizes the groundwater tracing results for the study area as currently known. Four of the seven traces included in this report were started outside the Jacks Fork topographic watershed, yet all dye traces were detected within the Jacks Fork watershed. The groundwater traces are discussed in greater detail in the OUL report on dye tracing that is appended to this report. The following paragraphs summarize the OUL report.

There is a substantial area outside of the Jacks Fork River topographic basin that contributes water to the Jacks Fork River through interbasin transfer of water. The demonstrated interbasin transfer of water is all discharged from Alley Spring. This additional area adds approximately 25% more land to the topographic watershed of the Jacks Fork River above Eminence. This additional land includes the town of Summersville, Missouri.

The travel times determined in this investigation for water passing through the sinkholes were somewhat shorter than survival times of fecal coliform bacteria in karst groundwater systems. If significant bacteria sources were present in sinkholes when a runoff event took place, bacteria could survive long enough to be discharged in the Jacks Fork River.

In 1999, OUL investigated groundwater impacts resulting from a sewer line break in Walkersville, Maryland. In that case, E. coli bacteria entered the groundwater system during a short time period. The peak concentration at a monitored water well occurred about 13 days after the sewer break. There were significant concentrations of fecal coliform bacteria until about 23 days after the sewer break (OUL unpublished data). The data were not clear as to whether the bacteria had died off or had been flushed through the system. However, in this investigation, water entering sinkholes was discharged into the Jacks Fork River in 4 to 35 days. This duration overlaps the survival time for E. coli bacteria.

There are many other sources of potential water quality degradation of the Jacks Fork River than bacteria. Suspended solids can travel through the groundwater system about as easily as do bacteria. Chemical contaminants that are appreciably soluble in water are less susceptible to natural cleansing than bacteria are in the karst groundwater system. Thus, both suspended solids and chemical contaminants are two potential threats to the water quality of the Jacks Fork River.

During this investigation, the tracing data were collected under relatively low flow conditions and over relatively long distances. At higher flow conditions and at closer sinkholes, the travel times to springs would be no more than half of what we determined in this investigation. Tables 1 and 2 show comparative data for the two previous traces, Summersville and Spring Valley, and the five traces conducted for this investigation.

Table 1. Summary of Dye Trace Lengths, Gradients, and Estimated Mean Velocities for the First Arrival of Tracer Dyes.

Trace Number

Trace Name

Sampling Station Linked

Length (ft)

Elevation loss (ft)

Gradient (ft/mile)

Mean Velocity of Dye Front (ft/day)

72-04

Summersville Trace

Alley Spring

58,770

465

42

14,693

78-01

Spring Valley Trace

Alley Spring

74,000

515

37

4,933

05-01

Smith Trace

Alley Spring

55,350

535

51

3,183

05-02

Thompson Trace

Alley Spring

66,105

540

43

1,927

05-03

Leroux Trace

Alley Spring

41,385

440

56

1,646

05-04

Anderson Trace

McCubbin Hollow Spring

5,945

240

213

1,243

05-05

Appleton Trace

Alley Spring

74,345

395

28

3,700

The velocity of groundwater in this investigation was lower than that demonstrated in earlier traces to the Jacks Fork River, as shown above in Table 1. However, velocity is a function of the amount of water available to flow through a given channel. If we assume that all of the Ozark Aquifer receives similar amounts of precipitation at similar times, then we can use the historic discharge data (NOAA, 2006) from the U.S. Geological Survey (USGS) for the gaging station on the Jacks Fork River at Highway 19 to compare flow conditions among the various traces.

The mean velocity in the historic data presented in Table 2 (extracted from Aley, 1977) is approximately 3.6 times the mean velocity demonstrated by the current groundwater tracing. However, the maximum discharge at the Highway 19 gaging station in the time period between the respective dye introductions and their first dye detections is approximately ten times as high for the historic data as contrasted with the data collected in this investigation. Stated simply, as the stream discharge increases, water velocity, including groundwater velocity, increases. The slower groundwater velocities revealed by the current investigation do not represent a different nature for this part of the Ozark Aquifer, but simply a response to different flow conditions during the time of tracing.

 

Table 2. Summary of the Performance of Sinkholes Recharging the Ozark Aquifer.

Trace Name

Velocity (ft/day)

Introduction

Date

Maximum Discharge*

Jacks Fork at Hwy 19 (CFS)

Dowler Sink Trace

15,840

12/10/71

4,500

West Plains Trace

8,808

6/14/72

265

Summersville Trace

14,693

11/1/72

7,400

Alton Dump Trace

1,008

5/28/69

267

Dora Dump Trace

1,560

7/22/71

127

Mean velocity (feet per day)

8,382

Mean maximum discharge

2,512

       

Smith Trace

3,183

10/4/05

200

Thompson Trace

1,927

10/4/05

170

Leroux Trace

1,646

10/5/05

150

Anderson Trace

1,243

12/8/05

365

Appleton Trace

3,700

12/7/05

390

Mean velocity (feet per day)

2,340

Mean maximum discharge

255

* Maximum discharge between dye introduction and the first detection.

 

In summary, the groundwater tracing data demonstrate several important findings. They are:

    1. Travel times for water passing through the sinkholes were somewhat shorter than survival times of fecal coliform bacteria in karst groundwater systems.
    2. This investigation was conducted during a period of relatively low flow conditions and consequently had longer travel times than would be normal.
    3. Soluble or suspended contaminants could easily pass through the groundwater system and degrade the Jacks Fork River.
    4. There is a substantial area outside of the Jacks Fork topographic basin that contributes water to the Jacks Fork River through interbasin transfer of water. This additional land includes the town of Summersville, Missouri.

  1. Summary and Recommendations

The GIS and mapping portion of this project provides the Jacks Fork Watershed Committee with a geographic information system (GIS) that includes an inventory and environmental assessment of sinkholes in and around the Jacks Fork watershed. Digital data from various agencies were compiled into an initial GIS which was then used to identify sinkhole locations and guide field investigations. Three hundred (300) sinkholes were investigated and evaluated as to the degree of potential negative environmental impact due to site conditions. The sinkholes were categorized according to the environmental action recommended – immediate, short-term, long-term, or no action needed.

Of the 300 sinkholes investigated, approximately 287 of the sinkholes are assessed as needing no action to remedy potential negative threats to the Jacks Fork River. The remaining 13 sinkholes should be addressed with long-term actions such as distribution of general public brochures and information packets that summarize the potential threat sinkholes can pose to groundwater and surface waters. These sinkholes showed accumulation of trash and other waste materials throughout the decades, mostly inorganic in nature such as appliance, tires and fencing material, which could demonstrate to future patrons that the area has long been accepted as a dumping site. The watershed management plan should not permit such an attitude to perpetuate itself or encourage potential pollution in the future.

Additional long-term actions that can be incorporated into the watershed management plan include working with local counties to adopt construction guidelines that include erosion and sediment control. These guidelines would help protect area water resources from potential pollution resulting from erosion and transportation of sediment. Erosion and sediment control guidelines have been developed for many communities in the state and several examples exist that could be modified to meet the specific concerns associated with the Jacks Fork watershed.

The dye tracing portion of this project improves upon past trace studies to delineate the general direction of groundwater flow and identify areas of recharge for the springs along the Jacks Fork River. Five (5) dye traces were performed by Ozark Underground Laboratory (OUL) to refine previous studies concerning the relationship between sinkholes and surface waters in the Jacks Fork Watershed. The groundwater tracing data show that despite relatively low flow conditions and consequently longer travel times than normal, travel times for water passing through the sinkholes were somewhat shorter than survival times of fecal coliform bacteria in karst groundwater systems. The data also demonstrate that soluble or suspended contaminants could easily pass through the groundwater system and degrade the Jacks Fork River, and that there is a substantial area outside the Jacks Fork topographic basin that contributes water to the Jacks Fork River through interbasin transfer of water.

The results of the dye tracing portion of this project confirm that sinkholes in the study area can potentially contribute to the bacteriological pollution in the Jacks Fork River if the bacteriological pollutants are flushed into the sinkholes. However, the GIS and mapping portion of this project did not reveal any sinkholes currently subjected to imminent bacteriological threats that require immediate or short-term environmental action.

While this project did not reveal any situations that showed evidence of on-going bacteriological contamination, the data collected were used to establish a sinkhole inventory database and associated GIS that can be incorporated into a watershed management plan. It must be realized that not every sinkhole in the watershed was mapped and subsequently assessed, and that based on the percentage of landowners who refused access to their property, there may be sinkholes in the watershed that can transport bacteriological contamination that could reach the Jacks Fork River under certain runoff and groundwater flow conditions.

This project serves as an initial step in developing a watershed management plan for the Jacks Fork watershed. As the Jacks Fork Watershed Committee continues to develop a watershed management plan for the Jacks Fork area, additional studies that may provide useful information include:

    • Dye tracing on-site wastewater systems and municipal wastewater collection systems that are adjacent to the Ozark National Scenic Riverways.

    • Conducting additional bacteriological investigations to refine previous studies performed along the Jacks Fork River to determine the type, quantity, and potential source of bacteriological contamination present in the Jacks Fork River in relationship to the time of year, local events, construction projects, and identification of other point source pollutants.

    • Conducting both dye tracing and bacteriological investigations on losing streams in the watershed thought to contribute water to the Jacks Fork River along groundwater flow paths.

The Watershed Committee should continue to work with local stakeholders to increase awareness of the issues contributing to the impairment of the Jacks Fork River. MoDNR’s 2004 TMDL document for the Jacks Fork River contains suggestions for resolving the bacteria impairment and lists possible sources of funding to implement solutions.


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