effect of the cedar river on the quality of the ground ...location of municipal wells and traces of...
TRANSCRIPT
Effect of the Cedar River on the Quality of the Ground-Water Supply for Cedar Rapids, Iowa
By PETER M. SCHULMEYER__________________
U.S. GEOLOGICAL SURVEY Water-Resources Investigations Report 94-4211
Prepared in cooperation with the CITY OF CEDAR RAPIDS, IOWA
Iowa City, Iowa 1995
U.S. DEPARTMENT OF THE INTERIOR
BRUCE BABBITT, Secretary
U.S. GEOLOGICAL SURVEY
GORDON P. EATON, Director
For additional information write to:
District ChiefU.S. Geological SurveyP.O. Box 1230Iowa City, Iowa 52240
Copies of this report can be purchased from:
U.S. Geological Survey Earth Science Information Center Open-File Reports Section Box25286, MS 517 Denver Federal Center Denver, Colorado 80225
CONTENTS
Abstract........................................................................................^Introduction ..............................................................................................................................................................................1
Purpose andScope..........................................................................................................................................................2Acknowledgments..........................................................................................................................................................2
Description of Study Area ........................................................................................................................................................2Location and Physical Setting........................................................................................................................................2Geology and Hydrology .................................................................................................................................................4Municipal Well Fields................................................................................................................................................... 10Intensive-Study Site...................................................................................................................................................... 10
Data Collection and Results ...................................................................................................................................................17Cedar River Discharge and Stage................................................................................................................................. 18Ground-Water Levels.................................................................................................................................................... 19Selected In-Situ Water-Quality Properties and Constituents ....................................................................................... 19
Specific Conductance .........................................................................................................................................19pH.......................................................................................................................................................................20Temperature ........................................................................................................................................................20Dissolved Oxygen...............................................................................................................................................21
Microscopic Particulate Analysis.................................................................................................................................21Effect of the Cedar River on Selected Water-Quality Properties and Constituents of the Alluvial Aquifer..........................24
Specific Conductance ...................................................................................................................................................29pH ...............................................................Temperature..................................................................................................................................................................31Dissolved Oxygen.........................................................................................................................................................33
Assessment of Relative Risk of Alluvial Aquifer to Contamination by Pathogens ..............................................................36Summary ................................................................................................................................................................................39References Cited.....................................................................................................................................................................41
FIGURES
1. Map showing location of study area, City of Cedar Rapids, Iowa..................................................................................32-5. Lithologic section:
2. A-A' in the Cedar Rapids West Well Field................................................................................................................53. B-B' in the Cedar Rapids East Well Field................................................................................................................64. C-C' in the Cedar Rapids Seminole Well Field........................................................................................................75. D-D' in the Cedar Rapids Seminole Well Field ......................................................................................................8
6-7. Maps showing:6. Location of municipal wells and traces of lithologic sections A-A' and B-B' in the Cedar Rapids East and
West Well Fields...................................................................................................................................................... 117. Location of municipal wells and traces of lithologic sections C-C' and D-D' in Cedar Rapids Seminole
Well Field................................................................................................................................................................128. Diagram of intensive study site in vicinity of Cedar Rapids municipal well Seminole 10........................................... 179. Daily mean discharge of the Cedar River at Cedar Rapids and collection dates of samples for microscopic
paniculate analysis, October 1992 through January 1994............................................................................................. 1810-20. Graphs showing:
10. Water levels in the Cedar River, Cedar Rapids municipal well Seminole 10, and observation wells CRM-3and CRM-4, February 1, 1993, through January 31, 1994......................................................................................20
11. Specific conductance and discharge for the Cedar River at Cedar Rapids gaging station from February 20through April 29 and June 25 through August 30, 1993.........................................................................................29
Contents III
FIGURES-Continued
12. pH and discharge of the Cedar River at Cedar Rapids gaging station from February 20 throughApril 29, 1993.........................................................................................................................................................30
13. Dissolved oxygen and discharge of the Cedar River at Cedar Rapids gaging station from February 20through April 30 and June 25 through August 30, 1993 ........................................................................................ 31
14. Specific conductance of water from the Cedar River, observation well CRM-4, and Cedar Rapids municipal well Seminole 10, and estimated traveltimes of water from the river to observation well CRM-4 and municipal well Seminole 10, February 1, 1993, through January 31, 1994.......................................32
15. Specific conductance of water from the Cedar River, observation well CRM-3, and the municipal water- treatment plant, February 1, 1993, through January 31, 1994................................................................................ 33
16. pH of water from the Cedar River, observation wells CRM-3 and CRM-4, and Cedar Rapids municipalwell Seminole 10 , February 1, 1993, through January 31, 1994........................................................................... 34
17. Temperature of water from the Cedar River, observation well CRM-4, and Cedar Rapids municipal well Seminole 10, and estimated traveltimes of water from the river to observation well CRM-4 and municipal well Seminole 10, February 1, 1993, through January 31, 1994............................................................................ 35
18. Temperature of water from the Cedar River, observation well CRM-3, and the municipal water-treatment plant, and estimated traveltimes of water from the river to observation well CRM-3, February 1, 1993, through January 31, 1994 ....................................................................................................................................... 36
19. Concentrations of dissolved oxygen in water from the Cedar River, observation well CRM-4, and Cedar Rapids municipal well Seminole 10, and estimated traveltimes for water from the river to observation well CRM-4 and municipal well Seminole 10, February 1, 1993, through January 31, 1994...............................37
20. Concentrations of dissolved oxygen in water from the Cedar River, observation well CRM-3, and the CedarRapids municipal water-treatment plant, February 1, 1993, through January 31, 1994......................................... 37
TABLES
1. Hydraulic properties for alluvial aquifer into which Cedar Rapids municipal wells are completed............................ 102. Construction information for municipal water wells, test holes, and observation wells in the vicinity of
Cedar Rapids, Iowa....................................................................................................................................................... 133. Results of microscopic particulate analysis for primary indicators in water from study area, December 1992
through November 1993 ...............................................................................................................................................224. Results of microscopic particulate analysis for secondary indicators in water from study area, December 1992
through November 1993 ...............................................................................................................................................255. Results of microscopic particulate analysis for selected water-quality properties and selected secondary
indicators in water from study area, December 1992 through November 1993........................................................... 276. Risk of surface-water contamination as determined by microscopic particulate analysis of water in the study
area, December 1992 through November 1993 ............................................................................................................ 387. Filtration efficiency calculated as a log-reduction rate between the Cedar River and selected municipal wells
and the Cedar Rapids municipal water-treatment plant, December 1992 through November 1993 ............................ 408. Mean daily water levels in the Cedar River at the surface-water monitoring site, February 1, 1993, through
January 31, 1994........................................................................................................................................................... 439. Mean daily water levels in observation well CRM-4, February 1, 1993, through January 31, 1994...........................44
10. Mean daily water levels in municipal well Seminole 10, February 1, 1993, through January 31, 1994......................4511. Mean daily water levels in observation well CRM-3, February 1, 1993, through January 31, 1994...........................4612. Water-level measurements for observation wells CRM-3, CRM-4, and CRM-6, February 1993 through
January 1994................................................................................................................................................................. 4713. Mean daily specific conductance of water from the Cedar River, surface-water monitoring site, February 1, 1993,
through January 31, 1994..............................................................................................................................................4814. Mean daily specific conductance of water from observation well CRM-4, February 1, 1993, through
January 31, 1994........................................................................................................................................................... 4915. Mean daily specific conductance of water from municipal well Seminole 10, February 1,1993, through
January 31, 1994........................................................................................................................................................... 5016. Mean daily specific conductance of water from observation well CRM-3, February 1, 1993, through
January 31, 1994........................................................................................................................................................... 51
IV Effect of the Cedar River on the Quality of tha Ground-Water Supply for Cedar Rapids, Iowa
TABLES Continued
17. Mean daily specific conductance of water from the Cedar Rapids municipal water-treatment plant,February 1, 1993, through January 31, 1994 ................................................................................................................52
18. Mean daily pH of water from the Cedar River, surface-water monitoring site, February 1, 1993, throughJanuary 31, 1994 ...........................................................................................................................................................53
19. Mean daily pH of water from observation well CRM-4, February 1, 1993, through January 31, 1994....................... 5420. Mean daily pH of water from municipal well Seminole 10, February 1, 1993, through January 31, 1994.................5521. Mean daily pH of water from observation well CRM-3, February 1, 1993, through January 31, 1994.......................5622. Mean daily pH of water from the Cedar Rapids municipal water-treatment plant, February 1, 1993,
through January 31, 1994...............................................................................................;..............................................5723. Mean daily temperature of water from the Cedar River, surface-water monitoring site, February 1, 1993,
through January 31, 1994..............................................................................................................................................5824. Mean daily temperature of water from observation well CRM-4, February 1, 1993, through January 31, 1994 ........ 5925. Mean daily temperature of water from municipal well Seminole 10, February 1, 1993, through January 31, 1994... 6026. Mean daily temperature of water from observation well CRM-3, February 1, 1993, through January 31, 1994 ........ 6127. Mean daily temperature of water from the Cedar Rapids municipal water-treatment plant, February 1, 1993,
through January 31, 1994.............................................................................................................................................. 6228. Mean daily concentration of dissolved oxygen in water from the Cedar River, surface-water monitoring
site, February 1, 1993, through January 31, 1994.........................................................................................................6329. Mean daily concentrations of dissolved oxygen in water from observation well CRM-4, February 1, 1993,
through January 31, 1994..............................................................................................................................................6430. Mean daily concentration of dissolved oxygen in water from municipal well Seminole 10, February 1, 1993,
through January 31, 1994..............................................................................................................................................6531. Mean daily concentrations of dissolved oxygen in water from observation well CRM-3, February 1, 1993,
through January 31, 1994.............................................................................................................................................. 6632. Mean daily concentrations of dissolved oxygen in water from the Cedar Rapids municipal water-treatment
plant, February 1, 1993, through January 31, 1994 ......................................................................................................6733. Numerical range of each primary bio-indicator counted per 100 gallons of water....................................................... 6834. Relative surface-water risk factors associated with scoring of primary bio-indicators present during microscopic
paniculate analysis of water from study area................................................................................................................ 68
CONVERSION FACTORS, ABBREVIATIONS, AND VERTICAL DATUM
Multiplyinch (in.)
foot (ft) mile (mi)
By25.4
0.3048 1.609
To obtainmillimeter meter kilometer
square mile (mi 2) 2.590 square kilometergallon (gal) 3.785 liter
million gallons (Mgal) 3,785 cubic metermillion gallons per day (Mgal/d) 3,785 cubic meter per day
gallon per minute (gal/min) 0.00006309 cubic meter per secondfoot per day (ft/d) 0.3048 meter per day
foot squared per day (ft2/d) 0.09290 meter squared per daycubic foot per second (ft3/d) 0.02832 cubic meter per second
gallon per day per foot [(gal/d)/ft] 0.01242 cubic meter per day per metergallon per minute per foot [(gal/min)/ft)______0.2070________liter per second per meter
Temperature in degrees Fahrenheint (°F) may be converted to degrees Celsius (°C) asfollows:degree Fahrenheit (°F) °C = (°F-32)/1.8 degree Celsius (°C)
Sea level: In this report, "sea level" refers to the National Geodetic Vertical Datum of 1929 (NGVD of 1929) a geodetic datum derived from a general adjustment of the first- order level nets of both the United States and Canada, formerly called Sea Level Datum of 1929.
Contents
Effect of the Cedar River on the Quality of the Ground-Water Supply for Cedar Rapids, IowaBy Peter M. Schulmeyer
Abstract
The Surface Water Treatment Rule under the 1986 Amendment to the Safe Drinking Water Act requires that public-water supplies be evaluated for susceptibility to surface-water effects. The alluvial aquifer adjacent to the Cedar River is evaluated for biogenic material and monitored for selected water-quality properties and constituents to determine the effect of surface water on the water supply for the City of Cedar Rapids, Iowa. Results from monitoring of selected water-quality properties and constituents showed an inverse relation to river stage or discharge. Water-quality properties and constituents of the alluvial aquifer changed as water flowed from the river to the municipal well as a result of drawdown. The values of specific conductance, pH, temperature, and dissolved oxygen at observation well CRM-4 and municipal well Seminole 10 generally follow the trends of values for the Cedar River. Values at observation well CRM-3 and the municipal water-treatment plant showed very little correlation with values from the river. The traveltime of water through the aquifer could be an indication of the suscep tibility of the alluvial aquifer to surface-water effects..Estimated traveltimes from the Cedar River to municipal well Seminole 10 ranged from 7 to 17 days.
Above-normal streamflow and precipitation during the study could have increased the effect the river had on the alluvial aquifer and on the possibility of contamination by a pathogen. Microscopic particulate analysis of 29 samples found no Giardia cysts or Crytosporidium oocysts
in water collected from municipal wells. Data also indicate that the aquifer is filtering out large numbers of algae, diatoms, rotifers, and nema- todes as well as filtering out Cryptosporidium, Giardia, and other protozoa. The number of algae, diatoms, rotifers, protozoa, and vegetative debris for selected municipal wells tested showed at least a reduction to 1 per 1,000 of the number found in the river. A relative risk factor and a log-reduction rate were determined for the aquifer in the vicinity of selected wells. One municipal well had a high-risk factor, three other wells had a moderate-risk factor, and four wells had a low-risk factor. The filtering efficiency of the aquifer is equivalent to a 3 log-reduction rate or 99.99-percent reduction in particulates.
INTRODUCTION
Enactment of the 1986 Amendment to the Safe Drinking Water Act prompted a new regulation for public-water systems that use surface water or ground water that is directly affected by surface water and is referred to as "ground water under the direct influence of surface water (GWUDI)." This regulation, called the Surface Water Treatment Rule (SWTR) (U.S. Environmental Protection Agency, 1989), declares that States have primary responsibility for identifying GWUDI's and their risk pertaining to waterborne diseases such as giardiasis (Vasconcelos and Harris, 1992) or cryptosporidiosis. From January 1991 to December 1992 seven outbreaks of such diseases were caused by protozoan origin, as reported by Morbidity and Mortality Weekly Report (Last, 1994). Four outbreaks were caused by Giardia with 123 cases reported, and three outbreaks were caused by Cryptosporidium with 3,551 cases reported (Last,
Introduction 1
1994). Both Giardia and Cryptosporidium are proto zoan parasites that can reside in the digestive tracks of vertebrates. These parasites may pass into surface water from the fecal material of animals or by surface- water runoff washing this material into streams or pools. Ground water can become contaminated if these parasites move with the surface water into a ground-water flow system.
Alluvial aquifers adjacent to large streams are an important source of ground water for many municipalities as a source of drinking water. The alluvial aquifer adjacent to the Cedar River, used by Cedar Rapids, Iowa, as a source of water supply, has tentatively been evaluated as GWUDI. GWUDI is defined as any water beneath the surface of the ground with either a significant occurrence of insects, other microorganisms, algae, organic debris, or large- diameter pathogens such as Giardia lamblia, or significant and relatively rapid changes in water- quality properties such as specific conductance, pH, temperature, or turbidity that closely correlate to climatological or surface-water conditions (U.S. Environmental Protection Agency, 1989). A coop erative study between the City of Cedar Rapids, Iowa, and the U.S. Geological Survey (USGS) was under taken to quantify the effect of the Cedar River on water quality of the adjacent alluvial aquifer. Results of this study will aid in an improved understanding of surface-water effects on ground water in alluvial systems.
Determining the effect that the Cedar River has on the alluvial aquifer required a review of depart mental and public-water-system records; inspection of wells and their construction records; and an evaluation of the water source, which involved microscopic particulate analysis (MPA) and monitoring of selected water-quality properties and constituents. The MPA evaluates ground-water samples for surface-water indicators such as Giardia, coccidia, diatoms, algae, insects, rotifers, vegetative debris, amorphous debris, pollen, spores, nematodes, crustaceans, amoeba, and protozoa. Evaluation of selected water-quality pro perties and constituents involves measuring the specific conductance, pH, temperature, and dissolved oxygen in the alluvial aquifer and the Cedar River. If similar changes occur in the alluvial aquifer adjacent to the Cedar River, this could indicate that the ground water is directly affected by surface water and, therefore, is GWUDI.
Purpose and Scope
This report describes the hydrologic and biogenic information collected from December 1992 through January 1994 to determine the effect of surface water from the Cedar River on water quality in the adjacent alluvial aquifer. Selected water-quality properties and constituents (specific conductance, pH, temperature, and dissolved oxygen) of the Cedar River were compared with those measured in the alluvial aquifer and the Cedar Rapids municipal water- treatment plant, and the biogenic particulates in samples collected from the Cedar River were com pared with samples collected from selected municipal wells in the alluvial aquifer and the water system as a whole.
Acknowledgments
The assistance of city officials and other person nel of the City of Cedar Rapids in well drilling, sample and data collection, and providing well information is here acknowledged and appreciated.
DESCRIPTION OF STUDY AREA
Location and Physical Setting
The study area is located in northwest Cedar Rapids, along the Cedar River in Linn County, east- central Iowa (fig. 1). The study area encompasses the East, Seminole, and West Well Fields that supply water to the City. There is a well-developed stream pattern that drains into the Cedar River, the largest tributary of the Iowa River. The river flows in a northwest-to-southeast direction through the study area (fig. 1). Approximately 1 mi southeast of the East Well Field is a low-head dam (fig. 1). This is used for flood control, to generate hydroelectric power, and to maintain river stage to provide a source of additional recharge to-the well fields, especially during periods of below-normal streamflow.
The Cedar River drainage basin upstream of the gage at Cedar Rapids has a surface area of 6,510 mi2 . Land use in the Cedar River Basin is predominantly agricultural (81 percent), with the major crops being corn and soybeans (U.S. Department of Agriculture, 1976). Annual precipitation ranges from 30 to 36 in., and seasonal temperatures vary from summer highs of
2 Effect of the Cedar River on the Quality of the Ground-Water Supply for Cedar Rapids, Iowa
Cedar River Basin
42°OV
41°59'
Base from U.S. Geological Survey digital data, 124,000,1983
Universal Transverse Mercator projection, zone 15
2 KILOMETERS
EXPLANATION
Streamflow-gaging station
Municipal well
Figure 1 . Location of study area, city of Cedar Rapids, Iowa.
Description of Study Area 3
100 °F to winter lows of -18 °F (Iowa Department of Environmental Quality, 1976).
The City of Cedar Rapids had a population of 108,751 in 1990 and has a steadily increasing demand for water (Bob Glass, City of Cedar Rapids Water Department, oral commun., 1994). There are 53 muni cipal wells that provide water for public and industrial needs. Pumpage from municipal wells was 8,487 Mgal in 1980, 9,118 Mgal in 1990, and 10,385 Mgal in 1992; the reporting period is from July 1 of the pre vious year through June 30 of the reporting year (Bob Glass, City of Cedar Rapids Water Department, oral commun., 1994).
Geology and Hydrology
Carbonate rock of Silurian and Devonian age comprise the bedrock aquifer, which is the most widely used aquifer in Linn County for industrial and domestic supply (Hansen, 1970). Overlying the bed rock is a layer of unconsolidated glacial till, loess, and alluvium. The thickness of this layer is variable, with a maximum thickness of 86 ft in the study area as inter preted from seismic refraction information. The allu vial deposits that underlie the flood plain and terraces of the Cedar River form the principal alluvial aquifer in the county. For a more detailed discussion of the geology of the area refer to Hansen (1970) and Prior (1991).
The Cedar River is a meandering stream that has cut into the bedrock surface, exposing steep valley walls in the study area. The flood plain is approx imately 3,500 ft wide near the Seminole Well Field and narrows to 1,200 ft near the West Well Field. The fluvial deposits in the study area show typical point- bar sedimentation. Tabular deposits of alluvial mat erial commonly have resulted from the lateral migra tion of the channel across the flood plain. Deposits of this type typically have an upward diminution of grain size (Reading, 1978). Driller's logs for most of the 53 municipal wells confirm this upward fining of material in the alluvial aquifer. Coarse-grained sand and gravel are found at the base of the alluvium. These grade into coarse- to fine-grained sand in the middle of the unit, with fine-grained sand, silt, and clay near the top. Cobbles and boulders are most prevalent at the East Well Field as noted in drillers logs.
Lithologic sections for the alluvial aquifer were developed using drillers logs (figs. 2, 3, 4, and 5) and show a typical vertical succession of grain size from
coarse sand and gravel at the base of the section to fine sand, silt, and clay at the top. Coarse sand and gravel are the most permeable of the materials present in the alluvial aquifer and, where they are thick, can provide the greatest potential for large yields of water (Hansen, 1970).
The alluvial aquifer is hydraulically connected to the Cedar River, bedrock, and upland areas in the study area. Recharge to the alluvial aquifer occurs as infiltration of precipitation, seepage from adjacent aquifers, and from the river when the stage is higher than the ground-water level (Wahl and Bunker, 1986). Normally, the alluvial aquifer receives enough recharge to maintain the water table above the stage of the river (Hansen, 1970). When the river stage is lower than the water table, the aquifer discharges into the river. The Cedar River can receive as much as 80 percent of its annual discharge from ground-water contribution (Squillace, Liszewski, and Thurman, 1993).
Alluvial aquifers can have large transmissivities and hydraulic conductivities, which makes them very desirable for water supplies because large amounts of water can be withdrawn. Hansen (1970) reported a maximum transmissivity of 150,000 (gal/d)/ft for a storage coefficient of 0.1 for the alluvial aquifer of the East and West Well Fields. The hydraulic conductivity for sand and gravel generally ranges from 2.8 to 2,834 ft/d (Freeze and Cherry, 1979). Single-well hyd raulic tests performed on the alluvial aquifer south of Cedar Rapids produced results ranging from 2.0 to 174.0 ft/d (Paul Squillace, USGS, written commun., 1994).
Specific capacity depends on both the hydraulic characteristics of the aquifer and construction of the well. Specific capacities for municipal wells, reported by the City of Cedar Rapids, are presented in table 1. Using a modified Theis equation, transmissivity can be calculated using the specific capacity of a well (Heath, 1987). Transmissivities for the alluvial aquifer in the vicinity of municipal well locations were calculated using this method and range from 1,543 to 19,240 f^/d (table 1). Hydraulic conductivities at each well loca tion (table 1) were calculated by dividing the trans missivity by the thickness of saturated material and range from 21.3 to 315.2 ft/d.
Fifteen wells are completed in a portion of the alluvial aquifer that has a transmissivity greater than 10,000 ft2/d. All of the wells are set close to the river. Except for municipal wells Seminole 9 and 10, West 9,
4 Effect of the Cedar River on the Quality of the Ground-Water Supply for Cedar Rapida, Iowa
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ER'S
lo"0
J_
Mun
icip
al w
ell N
ame
and
num
ber
corr
espo
nds
to t
hat
used
in
tabl
e 2
Sem
inol
e 10
Figu
res.
Li
thol
ogic
sec
tion
D-D
'in C
edar
Rap
ids
Sem
onol
e W
ell F
ield
.
Table 1. Hydraulic properties for alluvial aquifer in which Cedar Rapids municipal wells are completed[(gal/min)/ft, gallons per minute per foot of drawdown; ft2/d, foot squared per day; ft/d, foot per day; NR, no record]
Well name and number (figs. 6-7)
East 1East 2East3East 4East5
East 6EastSEast 9East 10East 11
East 12East 13East 14East 15East 16
East 17East 18East 19East 20West 1
West 2West3West 4West5West 6
West?WestS
Specific capacity [(gal/min)
/ft]
21.123.742.951.345.7
29.414.228.526.129.2
50.939.132.275.074.2
100.096.562.297.075.0
25.012.617.8
NR39.5
31.324.1
Trans- miss- ivity
(ft2/d)
2,7063,1536,1567,3626,558
4,0061,7383,8843,4723,979
7,3045,4394,388
11,46711,345
15,77014,7549,148
17,65011,467
3,3261,5432,283
NR5,597
4,3543,206
Hydraulic con
ductivity (ft/d)
38.743.885.5
102.391.7
57.225.058.051.870.4
119.789.267.5
171.1164.4
267.3250.1160.5315.2179.2
46.121.333.1
NR78.9
84.551.9
Well name and number
(figs. 6-7)
West 9West 10West 1 1Seminole 1Seminole 2
Seminole 3Seminole 4Seminole 5Seminole 6Seminole 7
Seminole 8Seminole 9Seminole 10Seminole 1 1Seminole 12
Seminole 13Seminole 14Seminole 15Seminole 16Seminole 17
Seminole 18Seminole 19Seminole 20Seminole 21Seminole 22
Seminole 23
Specific capacity [(gal/min)
/ft]
122.063.667.017.860.0
68.653.183.362.284.2
39.960.061.742.031.2
53.825.443.524.873.1
NRNRNRNRNR
NR
Trans- miss- ivity
(ft2/d)
19,2409,354
10,2442,793
10,537
12,4829,325
15,15710,92315,320
6,87710,53710,8366,0274,251
7,9133,3746,2423,296
11,177
NRNRNRNRNR
NR
Hydraulic con
ductivity (ft/d)
305.4139.6155.243.7
195.5
198.4169.9236.8178.8242.8
120.0183.3158.097.273.3
129.757.2
100.750.7
192.7
NRNRNRNRNR
NR
Description of Study Area 9
and East 20, these well are partially completed in a gravel lens of the alluvial aquifer (figs. 2, 3, and 5).
The Cedar River is the largest source of re charge available to the alluvial aquifer, and the rate of this recharge is dependent on the hydraulic conduct ivity of the aquifer, the hydraulic gradient between the river and the aquifer, and the infiltration capacity of the riverbed materials (Hansen, 1970). The withdrawal of water from a well constructed in the alluvial aquifer causes a depression of the water table surrounding the well called a "cone of depression." The withdrawal establishes a hydraulic gradient between the hydraulic head in the aquifer and the hydraulic head in the well, which causes water to flow from the surrounding aqui fer towards the well. With large hydraulic conduct ivities and transmissivities (table 1), large volumes of water can move through the aquifer to the wells; for example, 37.1 Mgal/d was obtained on May 21, 1994, from the alluvial aquifer by the Cedar Rapids muni cipal wells (Bob Glass, City of Cedar Rapids Water Department, oral commun., 1994).
Municipal Well Fields
The City of Cedar Rapids has three well fields in operation along the Cedar River (figs. 1, 6, and 7). There are a total of 53 municipal wells (table 2), with 19 wells in the East Well Field, 11 in the West Well Field, and 23 in Seminole Well Field. Seminole wells 17 through 23 were not in use during the study. The well fields are located in the flood plain of the Cedar River, and the ground surface at some municipal well locations is inundated during river flood stage. The wells are installed in the alluvium at varying distances from the river (table 2) and drilled to the top of the bedrock. Well depths range from 40 to about 72 ft.
All municipal wells are of similar construction. A 42- or 52-in. diameter hole was drilled with a rotary auger. A 30-in. diameter casing was installed with a 10- to 20-ft stainless-steel screen that has 0.08- to 0.10-in. slots. Screens for all municipal wells are set close to or on top of the bedrock. Gravel was used to fill the annular space around the screen area. The remainder of the annular space was sealed with clay, such as bentonite, and cement from the top of the gravel to land surface. A berm was built-up around the well to cover the seal. Well-construction information is presented in table 2.
Intensive-Study Site
The three well fields of the City of Cedar Rapids all have a similar lithologic sequence and hydraulic properties. This similarity in material and properties throughout the study area allowed the study to focus on one municipal well, Seminole 10, and to assume that the hydrologic interpretations for this well are applicable to other municipal well locations. The intensive-study site is located northwest of Cedar Rapids at municipal well Seminole 10 and adjacent to the Cedar River (figs. 7 and 8). The aquifer in the vicinity of municipal well Seminole 10 has a transmis- sivity of 10,836 ft2/d and a hydraulic conductivity of 158.0 ft/d, which is representative of the well fields. The well is 48 ft from the river, and its land-surface elevation is 725.4 ft (table 2).
Sixty feet of 6-in. diameter pipe were laid in a trench extending from the top of the riverbank down into the river, near municipal well Seminole 10, to monitor changes in water level and selected water- quality properties and constituents in the Cedar River (fig. 8). The trench was filled and covered with rip-rap for protection. The end of the pipe was perforated to allow for the free flow of water.
Two, 4-in. diameter observation wells, CRM-3 and CRM-4, were installed to monitor changes in water levels and selected water-quality properties and constituents in the alluvial aquifer. Wells CRM-4 and CRM-3 were placed between Seminole 10 and the river and beyond Seminole 10, respectively (fig. 8). The observation wells were installed in the alluvial aquifer by the USGS using a hollow-stem auger. CRM-3 is located 58 ft east, and well CRM-4 is located 22 ft west of municipal well Seminole 10 (fig. 8). Another 4-in. diameter observation well, CRM-6 (fig. 8), was installed into the bedrock. Depths for the observation wells are listed in table 2. The wells are constructed of schedule-80 polyvinyl chloride (PVC) pipe with a 2.5-ft screened interval at the bottom. The annular space was filled by allowing the sides to collapse in around the well casing after placement of the screen and pipe. A seal of bentonite clay was placed at a depth of 6 to 7 ft for wells CRM-3 and CRM-4 and at 80 ft for well CRM-6. Seal thickness varied between observation wells.
10 Effect of the Cedar River on the Quality of the Ground-Water Supply for Cedar Rapida, Iowa
91 0 40'20"
Base from U.S. Geological Survey digital data, 1:24,000,1983 Universal Transverse Mercator projection, zone 15
1 KILOMETER
EXPLANATION
A A' 0 Trace of litologic section
20. Municipal well and number
Figure 6. Location of municipal wells and traces of lithologic sections A-A' and B-B' in the Cedar Rapids East and West Well Fields.
Description of Study Area 11
91°42'40"
Seminole well field
Intensive study site (figure 8)J
Base from U.S. Geological Survey digital data, 1:24,000,1983 0 Universal Transverse Mercator projection, zone 15
0.5 1 KILOMETER
EXPLANATION C'0 Trace of litologic section
17. Municipal well and number
Figure 7. Location of municipal wells and traces .of lithologic sections C-C' and D-D' in Cedar Rapids Seminole Well Field.
12 Effect of the Cedar River on the Quality of the Ground-Weter Supply for Cedar Rapids, Iowa
Tabl
e 2.
Con
stru
ctio
n in
form
atio
n fo
r m
unic
ipal
wat
er w
ells
, tes
t ho
les,
and
obs
erva
tion
wel
ls in
the
vici
nity
of C
edar
Rap
ids,
Iow
a[ft
, fee
t; in
., in
ches
; N
R, n
o re
cord
]
Lat
itude
/long
itude
W
ell n
ame
and
num
ber
(deg
rees
, min
utes
, (f
igs.
6,7
, and
8)
seco
nds)
Land
- su
rfac
e el
evat
ion
(ft)
Wel
l de
pth
(ft)
Dep
th to
bo
ttom
of
seal
ed
annu
lar
spac
e (ft
)
Dia
met
er
of h
ole
(in.)
Dia
met
er
of c
asin
g (in
.)
Dep
th to
to
p of
w
ell
scre
en
(ft)
Len
gth
of w
ell
scre
en
(ft)
Late
ral
dist
ance
to
sur
face
w
ater
1 (ft
)M
unic
ipal
wel
ls
1 a o 3 a
Ced
ar R
apid
s E
ast
1C
edar
Rap
ids
Eas
t 2
Ced
ar R
apid
s E
ast
3C
edar
Rap
ids
Eas
t 4C
edar
Rap
ids
Eas
t 5
Ced
ar R
apid
s E
ast
6
Ced
ar R
apid
s E
ast
8
Ced
ar R
apid
s E
ast
9C
edar
Rap
ids
Eas
t 10
Ced
ar R
apid
s E
ast
1 1
Ced
ar R
apid
s E
ast
12C
edar
Rap
ids
Eas
t 13
Ced
ar R
apid
s E
ast
14C
edar
Rap
ids
Eas
t 15
Ced
ar R
apid
s E
ast
1 6
Ced
ar R
apid
s E
ast
17C
edar
Rap
ids
Eas
t 1 8
Ced
ar R
apid
s E
ast
19C
edar
Rap
ids
Eas
t 20
Ced
ar R
apid
s W
est
1
41°5
9'47
"41
°59'
49"
41°5
9"50
"41
°59'
52"
41°5
9'55
"
42°0
0'09
"
41°5
9'41
"41
°59'
44"
41°5
9'48
"41
°59'
50"
41°5
9'52
"41
°59'
55"
41°5
9'58
"41
°59'
59"
42°0
0'02
"
42°0
0'04
"42
°00'
07"
42°0
0'09
"42
°00'
H"
42°0
0'13
"
91°4
0'40
"91
°40'
45"
91°4
0'48
"91
°40'
48"
91°4
0'55
"
91°4
0'37
"
91°4
0'42
"91
°40'
48"
91°4
0'52
"91
°40'
56"
91°4
0'58
"91
°41'
01"
91°4
1'05
"
91°4
1'07
"91
°41'
09"
91°4
1'11
"91
°41
' 13"
91°4
1 ' 1
5"91
°41'
17"
91°4
1'29
"
728.
072
8.0
728.
0
728.
0
728.
0
726.
0
724.
0
725.
0
726.
0
726.
0
724.
0
724.
0
724.
0
724.
0
724.
0
721.
0
721.
0
721.
0
721.
0
724.
0
70 72 72 72 71.6
70 69.6
67 67 56.5
61 61 65 67 69 59 59 57 56 64
NR
NR
NR
NR
NR
NR
NR
NR 42 18 18 18 19 20 20 15 18 18 16 NR
42 42 42 42 42 42 42 52 42 42 42 42 42 42 42 42 42 42 52 NR
30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30
50 52 52 52 51.6
50 NR 54 52 36
.5
41 41 44.5
47 49 39 39 37 36 54
20 20 20 20 20 20 20 13 15 20 20 20 20 20 20 20 20 20 20 10
63 126
400
400 67 80 80 80 86 36 43 48 53 32 49 62 57 56 52 33
Tabl
e 2.
Con
stru
ctio
n in
form
atio
n fo
r m
unic
ipal
wat
er w
ells
, te
st h
oles
, an
d ob
serv
atio
n w
ells
in t
he v
icin
ity o
f Ced
ar R
apid
s, I
owa
Con
tinue
d
Effect
of
the
Ceda 3D I o 3 I 0 1 o f O 5 1 m n C/> c o 0 I 3D S u>
Wel
l nam
e an
d nu
mbe
r (f
igs.
6,7,
and
8)
Lat
itud
e/lo
ngit
ude
(deg
rees
, m
inut
es,
seco
nd
s)
Lan
d-
surf
ace
elev
atio
n (f
t)
Wel
l de
pth
(ft)
Dep
th to
bo
ttom
of
seal
ed
annu
lar
spac
e (ft
)
Dia
met
er
of h
ole
(in.)
Dia
met
er
of c
asin
g (in
.)
Dep
th to
to
p of
w
ell
scre
en
(ft)
Len
gth
of w
ell
scre
en
(ft)
Late
ral
dist
ance
to
sur
face
w
ater
1(ft
)M
unic
ipal
wel
ls C
ontin
ued
Ced
ar R
apid
s W
est 2
Ced
ar R
apid
s W
est 3
Ced
ar R
apid
s W
est 4
Ced
ar R
apid
s W
est 5
Ced
ar R
apid
s W
est 6
Ced
ar R
apid
s W
est 7
Ced
ar R
apid
s W
est
8
Ced
ar R
apid
s W
est 9
Ced
ar R
apid
s W
e si
10
Ced
ar R
apid
s W
est
11
Ced
ar R
apid
s Se
min
ole
1
Ced
ar R
apid
s Se
min
ole
2
Ced
ar R
apid
s Se
min
ole
3
Ced
ar R
apid
s Se
min
ole
4
Ced
ar R
apid
s Se
min
ole
5
42°0
0'17
"
42°0
0'26
"
42°0
0'29
"42
°00'
33"
42°0
0'37
"
42°0
0'36
"42
°00'
31"
42°0
0'32
"
41°0
0'36
"
42°0
0'37
"
42°0
0'31
"
42°0
0'24
"
42°0
0'19
"
42°0
0'15
"
42°0
0'09
"
91°4
1'34
"91
°41'
47"
91°4
1'53
"91
°42'
02"
91°4
2'14
"
91°4
2'28
"
91°4
2'36
"91
°41'
57"
91°4
2'07
"
91°4
2'22
"
91°4
2'47
"
91°4
2'58
"
91°4
3'05
"
91°4
3'12
"
91°4
3'18
"
723.
072
3.0
724.
0
723.
072
3.0
724.
072
4.0
724.
0
724.
0
724.
0
720.
0
720.
0
720.
0
720.
0
720.
0
72.2
72.4
69 68 70.9
51.5
61.8
63 67 66 64 53.9
62.9
54.9
64
NR
NR
NR
NR
NR
NR
NR 38 42 41 5
NR 20 10 15
NR
NR
NR
NR
NR
NR
NR 42 42 42 52 NR 52 52 52
30 30 30 30 30 30 30 30 30 30 30 30 30 30 30
62.2
62.4
54 53 NR 36
.551
.848 52 51 53
.8
43.9
52.6
34.7
53.7
10 10 15 15 NR 15 10 15 15 15 10
.2
10 10.2
10.2
10.2
68 31 90 132 93 30 30 38 64 67 62 38 100
210 42
Tab
le 2
. C
onst
ruct
ion
info
rmat
ion
for
mun
icip
al w
ater
wel
ls,
test
hol
es,
and
obse
rvat
ion
wel
ls in
the
vici
nity
of
Ced
ar R
apid
s, I
ow
a C
ontin
ued
Wel
l na
me
and
num
ber
(fig
s. 6
,7, a
nd 8
)
Lat
itude
/long
itude
(d
egre
es,
min
utes
, se
cond
s)
Lan
d-
surf
ace
elev
atio
n (f
t)
Wel
l de
pth
(ft)
Dep
th to
bo
ttom
of
seal
ed
annu
lar
spac
e (f
t)
Dia
met
er
of h
ole
(in.)
Dia
met
er
of c
asin
g (in
.)
Dep
th to
to
p of
w
ell
scre
en
(ft)
Len
gth
of w
ell
scre
en
(ft)
Lat
eral
di
stan
ce
to s
urfa
ce
wat
er1
(ft)
Mun
icip
al w
ells
C
ontin
ued
1
f 0 a w
Ced
ar R
apid
s Se
min
ole
6
Ced
ar R
apid
s Se
min
ole
7
Ced
ar R
apid
s Se
min
ole
8
Ced
ar R
apid
s Se
min
ole
9
Ced
ar R
apid
s Se
min
ole
10
Ced
ar R
apid
s Se
min
ole
1 1
Ced
ar R
apid
s Se
min
ole
1 2
Ced
ar R
apid
s Se
min
ole
1 3
Ced
ar R
apid
s Se
min
ole
14
Ced
ar R
apid
s Se
min
ole
15
Ced
ar R
apid
s Se
min
ole
16
Ced
ar R
apid
s Se
min
ole
17
Ced
ar R
apid
s Se
min
ole
18
Ced
ar R
apid
s Se
min
ole
19
Ced
ar R
apid
s Se
min
ole
20
Ced
ar R
apid
s Se
min
ole
21
Ced
ar R
apid
s Se
min
ole
22
Ced
ar R
apid
s Se
min
ole
23
42°0
0'04
"
42°0
0'00
"
41°5
9'56
"
41°5
9'53
"
41°5
9'54
"
42°0
0'23
"
42°0
0'15
"
42°0
0'17
"
42°0
0'20
"
42°0
0'25
"
42°0
0'30
"
42°0
0'13
"
42°0
0'13
"
42°0
0'14
"
42°0
0'19
"
42°0
0'24
"
42°0
0'30
"
42°0
0'35
"
91°4
3'24
"
91°4
3'31
"
91°4
3'37
"
91°4
3'46
"
91°4
3'53
"
91°4
3'03
"
91°4
4'13
"
91°4
4'20
"
91°4
4'25
"
91°4
4'27
"
91°4
4'30
"
91°4
4'19
"
91°4
4'27
"
91°4
4'34
"
91°4
4'39
"
91°4
4'40
"
91°4
4'41
"
91°4
4'41
"
721.
0
721.
0
722.
0
724.
0
725.
4
722.
0
724.
0
724.
0
725.
0
727.
0
726.
0
724.
0
724.
0
724.
0
719.
0
718.
0
721.
0
724.
0
61.1
63.1
57.3
57.5
68.6
62 58 61 59 62 65 58 52 40 43 51.7
57 57
16.6 5 1.1
12.2 5 37 N
RN
RN
RN
R
NR 34 20 14 10 14 14 14
52 52 52 52 52 42 42 42 42 42 42 42 42 42 42 42 42 42
30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30
50.9
52.9
47.1
47.2
58.4
47 43 46 44 47 50 34 32 28 28 36.7
42 40
10.2
10.2
10.2
10.2
10.2
15 15 15 15 15 15 20 20 12 15 15 15 17
41 60 116
115 48 235
500
500
800
800
900 63 81 75 52 78 86 70
Tabl
e 2.
Con
stru
ctio
n in
form
atio
n fo
r m
unic
ipal
wat
er w
ells
, te
st h
oles
, an
d ob
serv
atio
n w
ells
in th
e vi
cini
ty o
f Ced
ar R
apid
s, I
owa
Con
tinue
d
3 o a Er o O £ D> 3) 1 O 3
Dep
th to
bo
ttom
of
Wel
l nam
e an
d nu
mbe
r(f
igs.
6,7
, and
8)
Test
Hol
e 10
- A
Test
Hol
e 10
-B
Latit
ude/
long
itude
(deg
rees
, min
utes
,se
cond
s)
NR
NR
Land
-su
rfac
eel
evat
ion
(ft)
725.
0
725.
0
Wel
lde
pth
(ft)
Test
hol
es
40.0
45.0
seal
edan
nula
rsp
ace
(ft)
NR
NR
Dia
met
erof
hol
e(in
.)
NR
NR
Dia
met
erof
cas
ing
(in.)
NR
NR
Dep
th to
top
ofw
ell
scre
en(f
t)
NR
NR
Leng
thof
wel
lsc
reen
(ft)
NR
NR
Late
ral
dist
ance
to s
urfa
cew
ater
1(f
t)
NR
NR
to
Ob
serv
atio
n w
ells
O s 3 9. Er o
1993
US
GS
CR
M-3
1993
US
GS
CR
M-4
1993
US
GS
CR
M-6
41°5
9'53
"91°
43'5
0"
41°5
9'53
"91°
43'5
3"
41°5
9'54
"91°
43'5
3"
725.
9
725.
8
725.
7
39.5
42.5
95
6 7 80
6 6 6
4 4 4
37 40 92.5
2.5
2.5
2.5
1 06 26 30
o 3
'Lat
eral
dis
tanc
es to
sur
face
-wat
er s
ourc
e w
ere
mea
sure
d on
Mar
ch 2
2, 1
994.
Wat
er-s
urfa
ce e
leva
tion
at s
urfa
ce-w
ater
mon
itori
ng s
ite (
fig. 8
) w
as 7
17.4
5 fe
et
abov
e se
a le
vel.
(/) o o o o
91=43'53 - 91"43'50'
41°59'52'
CRM-6yCRM-4y
Seminole-10o CRM-3y
Base from U.S. Geological Survey 1:24.000 Cedar Rapids South, Iowa, 1967
30 40 FEET-1
10 METERS
EXPLANATION
A Surface-water-quality monitoring site
CRM-4^ Observation well Name and number correspond to the used in table 2
emmo e-iOQ Municipal well Name and number correspond to that used in table 2
Figure 8. Intensive study site in vicinity of Cedar Rapids municipal well Seminole 10.
DATA COLLECTION AND RESULTS
A multiprobe instrument, Hydrolab DataSonde@3 , was used to continuously monitor water level, specific conductance, pH, temperature, and dissolved oxygen in the Cedar River, observation
'Any use of product names is for descriptive purposes only and does not constitute endorsement by the U.S. Geological Survey.
wells CRM-3 and CRM-4, and municipal well Semi nole 10 (fig. 8). The Cedar Rapids municipal water- treatment plant (fig. 6) also was monitored for the selected water-quality properties and constituents. The data were recorded at 15-, 30-, or 60-minute intervals and are stored in the National Water Information System (NWIS) data base of the USGS. Selected water-quality properties and constituents, and surface- water biogenic particulates were collected at the inten-
Data Collection and Results 17
o o01 COccLJJ Q.
100,000
70,00060,00050,00040,000
30,000
20,000
5 10,000
7,0006,0005,0004,000
uH
UJ
cc< 3,000U52 2,000
1,000
I 1
Discharge
MPA sampling
N 1992
I________I________[_
JFMAMJJASOND1993
J 1994
Figure 9. Daily mean discharge of the Cedar River at Cedar Rapids and collection dates of samples for microscopic particulate analysis (MPA), October 1992 through January 1994.
sive study site (figs. 7 and 8), while discharge measurements were collected about 5 mi downstream from the intensive study site below the low-head dam (fig. 1).
The multiprobes in observation wells CRM-3 and CRM-4 were attached to a packer to isolate the instrument in the screened section of the well. Multi- probes were secured in the wells on a cable attached to the well caps. The multiprobe for the Cedar Rapids municipal water-treatment plant was placed just before the first step in the treatment process. Data from the multiprobes were retrieved every 2 weeks. During the winter months, retrieval of data from the river multi- probe was less frequent due to water freezing in the pipe. After data retrieval multiprobes were recali brated and returned to the monitoring point. Specific- conductance, pH, and dissolved-oxygen values were adjusted automatically by the multiprobe for temperature.
Cedar River Discharge and Stage
Discharge of the Cedar River is systematically measured as part of the long-term, ongoing USGS data-collection program (Southard and others, 1994). Discharge measurements used in this study were made at the USGS gaging station at Cedar Rapids located 3,000 ft downstream of the low-head dam (fig. 1). The annual mean monthly flow for 1903 to 1993 at the USGS gaging station at Cedar Rapids is 3,658 ftVs. The highest daily mean of 71,500 ft3/s occurred on March 31, 1-961, and the lowest daily mean of 140 ftVs occurred on November 18, 1989 (Southard and others, 1994).
For the period of this study, December 1992 to January 1994, the highest daily mean discharge of 70,500 ft3/s occurred on April 4, 1993; the lowest daily mean of 1,600 ft3/s occurred on February 23, 1993, and the annual mean monthly flow was 15,130 ft3/s. A hydrograph (fig. 9) for the Cedar River
18 Effect of the Cedar River on the Quality of the Ground-Water Supply for Cedar Rapids, lowe
at Cedar Rapids shows the mean daily discharge. Conditions during most of the study period were about 400 percent of normal for discharge and runoff. Annual runoff during the study was 31.55 in. com pared to the mean annual runoff of 7.64 in. Due to the above-normal conditions the low-head dam had little effect on the flow of the river, which normally withholds and releases water to generate power during peak hours.
Stage of the Cedar River was measured by the multiprobe at the intensive-study site. Stage data are shown in figure 10. Records show that the ground surface at municipal well Seminole 10 was inundated four times by the Cedar River in 1993 once in April, twice in July, and once in August.
drawdown from pumping. Water levels measured February 1 through 9, 1993, show that the direction of ground-water flow was from the alluvial aquifer to the river. During this period, municipal well Seminole 10 was not pumping.
On November 4 and December 20, 1993, com- arative water levels for observation wells CRM-3, CRM-4, and CRM-6 indicate that ground-water flow from the bedrock aquifer was upward toward the allu vial aquifer. The upward gradient indicates that the bedrock is a source of recharge to the alluvial aquifer at this location.
Selected In-Situ Water-Quality Properties and Constituents
Ground-Water Levels
The multiprobes in observation wells CRM-3 and CRM-4 were fitted with strain gages to measure water levels within a range of 0-33 ft with a precision of 0.15 ft. The multiprobe used in municipal well Seminole 10 was fitted with a strain gage to measure water levels within a range of 0-328 ft with a precision of 1.48 ft (Hydrolab Corporation, 1991). The water- level sensor automatically compensated for water density. Periodically, manual water-level measure ments were made with a steel tape and were recorded to within 0.01 ft to verify the multiprobe measurements.
Mean daily water levels for observation wells CRM-3 and CRM-4 and municipal well Seminole 10 are listed in tables 8 through 11 at the end of this report and are graphically compared to stage of the Cedar River in figure 10. The majority of missing water-level data for well CRM-4 resulted from water levels exce eding the tolerance of the sensor. Results of periodic manual measurements in wells CRM-3, CRM-4, and CRM-6 are listed in table 12 at the end of this report.
Water levels for wells CRM-3 and CRM-4 closely follow the stage of the river. During pumping, municipal well Seminole 10 drawdown causes the water level to range from 12 to 20 ft below river stage, which results in a steep gradient between the Cedar River and well Seminole 10. The direction of ground- water flow is toward the well. When the well was not pumping, water levels in wells CRM-3, CRM-4, and Seminole 10 were similar to the level of the river.
Generally the direction of ground-water flow was from the river to the alluvial aquifer as a result of
Specific Conductance
The mean daily specific-conductance values for water in the Cedar River ranged from a maximum value of 640 |o,S/cm (microsiemens per centimeter at 25 °C) on February 1, 1993, to a minimum value of 223 |J.S/cm on March 5, 1993. Maximum and minimum values for mean daily specific conductance for observation well CRM-4 and municipal well Seminole 10 are similar in range and time period to those of the river. Observation well CRM-4 had a maximum value of 658 [iS/cm on February 25, 1993, and the minimum value of 272 |o,S/cm on March 10, 1993. Municipal well Seminole 10 had a maximum values of 640 [iS/cm on January 11 and 12, 1994; 635 [iS/cm on February 15, 1993; and 636 (0,S/cm on March 3, 1993. The minimum value for well Seminole 10 was 287 [iS/cm on April 10, 1993. Values of mean daily specific conductance for observation well CRM-3 and the municipal water-treatment plant were less similar to values in the river. The maximum was 655 [iS/cm on February 17, 1993, and the minimum was 426 (iS/cm on May 14, 1993, for observation well CRM-3. The maximum specific-conductance value for the municipal water-treatment plant was 602 (o,S/cm on March 2, 1993, and the minimum value was 418 [iS/cm on August 20, 1993. Mean daily specific conductance values are tabulated at the end of this report in tables 13 through 17.
PH
The data show no significant or rapid changes in pH for water from wells and the municipal water- treatment plant compared to that from the Cedar River.
Data Collection and Results 19
LLJ
735
730
725
720
715
710
705
LLJw 700LLJ
g 695
Note: Breaks in lines indicate no data.Cedar River
Observation well CRM-4Observation
well CRM-3
Municipal well Seminole 10
February March April May June July1993
Observation well CRM-3 Observation
well CRM-4
Municipal well Seminole 10
August September October 1993
November December January 1994
Figure 10. Water levels in the Cedar River, Cedar Rapids municipal well Seminole 10, and observation wells CRM-3 and CRM-4, February 1, 1993, through January 31, 1994.
The pH data are tabulated in tables 18 through 22 at the end of this report. The daily mean pH values for the river water ranged from a minimum of 7.3 in March 1993 to a maximum of 8.5 in May and June of 1993. Values for observation well CRM-4 were similar in range from 7.4 to 8.2 and for municipal well Seminole 10 from 7.2 to 8.0. pH. Values of pH for water from observation well CRM-3 and the muni cipal water-treatment plant were smaller, ranging from 6.9 to 7.5 and 6.3 to 7.5, respectively.
Temperature
Maximum mean daily river temperature was 24.6 °C on August 27, 1993, and a minimum mean daily temperature of -0.1 °C was recorded from February 1 through March 6, 1993, and from December 23, 1993, through January 25, 1994. Maximum and minimum mean daily values for observation well CRM-4 were 24.5 °C on September 3, 1993, and 0.1 °C from February 14 through March 14,1993 and from December 31, 1993, through January 31, 1994. Maximum and minimum
20 Effect of the Cedar River on the Quality of the Ground-Water Supply for Cedar Rapids, Iowa
mean daily values for municipal well Seminole 10 were 21.4 °C on September 13, 1993, and -0.2 °C from February 5-16, 1993, and on January 23, 24, and 26-29, 1994. Maximum and minimum mean daily values for observation well CRM-3 were 18.7 °C on December 2, 1993, and 0.6 °C from February 10-13, 1993. Maximum and minimum mean daily values for the municipal water-treatment plant were 17.6 °C on September 13, 1993, and 5.9 °C on April 10, 1993. Mean daily temperature values are tabulated at the end of this report in tables 23 through 27.
The water temperatures for observation well CRM-4 seem to follow the trend of water temperatures in the Cedar River. Water temperatures for municipal well Seminole 10 also follow the trend of water tem peratures in the river but not as closely as those for observation well CRM-4. Water temperatures for observation well CRM-3 and the municipal water- treatment plant do not follow the variations in water temperatures for the river as the temperature in the river increases and decreases throughout the year.
Dissolved Oxygen
The Cedar River had a maximum concentration of dissolved oxygen of 15.2 mg/L on February 3, 1993, and a minimum concentration of 6.0 mg/L on August 20, 1993. Maximum and minimum concentra tions for observation well CRM-4 were 12.3 mg/L on December 28, 1993, and 0.1 mg/L on September 2, 1993. Maximum and minimum concentrations for municipal well Seminole 10 were 11.5 mg/L on January 2, 1994, and 0.4 mg/L from February 1-3, February 10, August 1-5 and 17-23, and September 11-13 and 15-18, 1993. Maximum and minimum concentrations for observation well CRM-3 were 3.1 mg/L on February 10, 1993, and 0.2 mg/L from February 14-16, November 10, 25, 26, and 28, December 3-5, 1993, and on January 31, 1994. Maximum and minimum concentrations for the muni cipal water-treatment plant were 11.2 mg/L on July 17, 1993, and 0.4 mg/L on February 25, 1993. Mean daily concentration values of dissolved oxygen are tabulated at the end of this report in tables 28 through 32.
Concentrations of dissolved oxygen in the river tend to be higher than the dissolved-oxygen concentra tions in water from observation well CRM-4, muni cipal well Seminole 10, observation well CRM-3, and the water-treatment plant. The trend of dissolved- oxygen concentration in well CRM-4 is similar to the concentrations in the river but in smaller quantities.
Concentrations in well Seminole 10 are similar to concentrations in well CRM-4 except during May through September. Dissolved-oxygen concentrations in well CRM-3 were fairly stable throughout the study period.
Microscopic Particulate Analysis
Microscopic paniculate data were collected using the method outlined by the U. S. Environmental Protection Agency (USEPA) to determine if a ground- water source is GWUDI according to the SWTR (Vasconcelos and Harris, 1992). Prior to sampling, municipal wells were pumped for a minium of 1 week to assure sufficient time for aquifer conditions to stab ilize. Samples were collected from the Cedar River, municipal wells East 1 and 19, West 6, and Seminole 2, 3, 10, 14, and 16, and the Cedar Rapids municipal water-treatment plant during April 1993, a period of above-normal flow. Additional samples for the river and Seminole wells 10, 14, and 16 were collected throughout the study period. Samples collected during a period of high flow, when several wells were inun dated, are important because the alluvial aquifer could be at a higher risk of contamination by surface water during this period. Samples were collected by USGS personnel and sent to the laboratory of Analytical Services, Inc., in Essex Junction, Vermont, for MPA.
Analysis of 29 samples found no Giardia cysts or Crytosporidium oocysts in water collected from municipal wells and the municipal water-treatment plant (table 3). A total of five Giardia cysts and four Crytosporidium oocysts were detected in the Cedar River samples, some with and some without internal structure.
Chlorophyll-containing algae (table 3) were detected in all but one of the wells sampled. The algae counts in the selected wells generally were insigni ficant compared to the algae counts in the river water. The largest counts occurred during flooding in April 1993. Counts of algae found in samples from the municipal water-treatment plant and municipal wells Seminole 3, 14, and 16 ranged from 1.9 x 103 to 7.9 x 104 per 100 gal of water during this time, three orders of magnitude higher than normally found. In comparison, the river samples contained algae counts of 1.6 x 107 to 3.8 x 107per 100 gal of water, whereas samples from municipal wells East 1 and 9, West 6, and Seminole 2 and 10 contained counts ranging from 1 to 16 per 100 gal.
Data Collection and Reauita 21
Tabl
e 3.
Res
ults
of m
icro
scop
ic p
artic
ulat
e an
alys
is fo
r pr
imar
y in
dica
tors
in w
ater
from
stu
dy a
rea,
Dec
embe
r 19
92 th
roug
h N
ovem
ber
1993
[Val
ues
are
coun
ts p
er 1
00 g
allo
ns o
f wat
er, e
xcep
t as
not
ed;
I, in
unda
ted
at th
e tim
e of
sam
plin
g; N
D, n
ot d
etec
ted]
m r+ a 1 31 | 0 3 1 O c » a 1 o 5 c 3 a i 0 I? TJ o, 31 g S 31 T
J &
Dat
e M
unic
ipal
wel
ls o
r sa
mpl
ing
site
(m
onth
- (f
igs.
6 a
nd 7
) da
y-ye
ar)
Ced
ar R
iver
12
-07-
9204
-06-
9304
-13-
9304
-26-
9308
-02-
9311
-16-
93
Ced
ar R
apid
s m
unic
ipal
wat
er-
04-0
6-93
trea
tmen
t pla
nt
04-0
7-93
04-0
8-93
04-2
6-93
Gia
rdia
cy
sts
2 1N
DN
DN
D 2
ND
ND
ND
ND
Cry
pto-
sp
orid
lum
oo
cyst
s
ND 3
ND
ND 1
ND
ND
ND
ND
ND
Veg
etat
ive
debr
is
l.Oxl
O3
l.lx
lO3
l.Oxl
O3
l.Oxl
O3
ND
ND 2
ND
ND 4
Dia
tom
s
1.2x
l04
5.7x
l05
5.1x
l05
2.7x
l03
ND 3.
3xl0
3
1 1N
DN
D
Alg
ae
7.4x
l06
l.Sxl
O7
3.4x
1 07
1.6x
l07
2.3x
l05
6.0x
l07
7.9x
1 04
1.9x
l04
l.lx
lO4
2.7x
1 04
Prot
ozoa
1.7x
l06
1.2x
l06
1.9x
l06
7.8x
l05
6.4x
1 03
ND l.S
xlO
216 ND 4.
1xl0
3
Inse
cts
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
Inse
ct
part
s
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
Ced
ar R
apid
s m
unic
ipal
wel
ls
Eas
t 1
04-1
4-93
Eas
t 19
04
-26-
93 I
Wes
t 6
04-1
5-93
04-2
6-93
ND
ND
ND
ND
ND
ND
ND
ND
1
ND
ND
ND
ND 2
ND
ND
16 8 1 4
2.0x
l03
2.4x
l03
3.5x
l04
63
ND
ND
ND
ND
ND
ND
ND
ND
Sem
inol
e 2
04-1
5-93
1N
DN
DN
DN
D4
-lxlO
3N
DN
D
Sem
inol
e 3
04-1
5-93
109
-22-
9311
-16-
93
ND
ND
ND
ND
ND
ND
ND
ND
ND
8N
DN
D
1.9x
l03
22 35
2.0x
1 03
ND 29
ND
ND
ND
ND
ND
ND
Tabl
e 3.
Res
ults
of
mic
rosc
opic
par
ticul
ate
anal
ysis
for
prim
ary
indi
cato
rs in
wat
er fr
om s
tudy
are
a, D
ecem
ber
1992
thro
ugh
Nov
embe
r 19
93 C
ontin
ued
Mun
icip
al w
ells
or
sam
plin
g si
te
(fig
s. 6
and
7)
Dat
e (m
onth
- da
y-ye
ar)
Gia
rdia
cy
sts
Cry
pto-
sp
orid
ium
oo
cyst
sV
eget
ativ
e de
bris
Dia
tom
sA
lgae
Prot
ozoa
Inse
cts
Inse
ct
part
sC
edar
Riv
er m
unic
ipal
wel
ls C
ontin
ued
Sem
inoi
e 10
Sem
inol
e 14
Sem
inoi
e 16
12-0
8-92
04-1
3-93
09-2
2-93
11-1
6-93
04-0
6-93
I08
-02-
9311
-16-
93
04-0
6-93
I04
-07-
93 I
08-0
2-93
11-1
6-93
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
1N
DN
DN
D
ND
ND
ND
ND
ND
ND
ND
ND 2
ND
ND
ND
ND
ND
ND
ND
ND
ND
8 9N
D 25 4.0x
1 03
34 2 3.7x
1 03
1.6x
l04
47 2
4 2.4x
1 03
3.6x
1 03
6.5x
1 02
36 ND 17 2.
0xl0
27
ND 3
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
o D> s o D> 3
Q.
C
;»
in
Diatoms (table 3) were found only in samples from three wells and the municipal water-treatment plant during the period of flooding. The counts ranged from 1 to 8 compared to counts ranging from 2.7 x 103 to 5.7 x 107 per 100 gal in the river samples through out the period of sampling. The count of rotifers found in the wells also was small compared to those found in the river samples (table 4). Some free-living rotifers have highly specialized food habits not associated with surface water if sufficient organic debris, fungi, and bacteria are present as a food supply (Vasconcelos and Harris, 1992). Vegetative debris (table 4), spores, pollen, crustaceans, crustacean eggs, nematodes, nematode eggs, amoebae, and invertebrate eggs (table 5) all showed very small counts in the well samples compared to the larger counts in the river samples. No insects or insect parts were found in any of the samples collected (table 4). Results for volume of sample filtered, turbidity, filter color, pH of sample, and amorphous debris are presented in table 5. Turbi dity of water from the wells sampled is generally less than the turbidity of the river except where wells have a high occurrence of iron bacteria.
EFFECT OF THE CEDAR RIVER ON SELECTED WATER-QUALITY PROPERTIES AND CONSTITUENTS OF THE ALLUVIAL AQUIFER
Variations in the specific conductance, pH, temperature, and dissolved-oxygen concentrations of water in the alluvial aquifer can be related to the Cedar River. Before addressing these relations, some aspects of water-quality variations in the Cedar River and traveltimes of water in the alluvial aquifer are discussed.
Specific conductance, pH, and the concentra tion of dissolved oxygen change inversely with changes in river stage or discharge (Schulmeyer, 1991). Increases in discharge of the Cedar River resulting from runoff had an inverse effect on the values of specific conductance, pH, and concentration of dissolved oxygen in the river as a resu! f of dilution (figs. 11, 12, and 13). Precipitation, resulting in ove-- land flow generallv hp« a smaller specific condnrtar.ee and pH, ranging from 5 to 74 jaS/cm and 4.0 to 7.3 pH (Southhard and others, 1994), respectively, compared
to the specific conductance and pH of ground water in alluvial and bedrock aquifers, which ranges from 390 to 1,800 nS/cm and 6.8 to 8.0 pH (Wahl and Bunker, 1986). Because the Cedar River can receive a major part of its flow from ground-water contribution, especially during periods of below-normal precipi tation, the specific-conductance, pH, and dissolved- oxygen values of river water can be similar to values measured in the ground water. When runoff occurs dilution takes place. With a large amount of runoff, substantial decreases in values of specific conduct ance, pH, and dissolved oxygen for water from the Cedar River can take place. Subsequently, these changes can be seen in the alluvial aquifer as water from the river moves toward municipal well Seminole 10 over a period of time.
Water-quality properties and constituents of water pumped from the alluvial aquifer change as water flows from the Cedar River to municipal well Seminole 10 as a result of drawdown. The amount of time needed for water to travel through the aquifer could be an indication of the susceptibility of the allu vial aquifer to surface-water effects. Giardia cysts have a period of viability dependent on length of time in the environment and temperature (Wilson and others, 1992). Viability is largely lost in about 20 days in water at 20 °C, 30 days in water at 10 °C, and 90 days in water of only a few degrees Celsius (Wilson and others, 1992). Traveltime represents the residence time the water has in contact with the aquifer material, which may enhance the filtering efficiency of the aquifer material.
The most notable example of change started on February 28, 1993, in the Cedar River for specific conductance, pH, and dissolved oxygen. The values for specific conductance and pH and the concentration of dissolved oxygen decreased with a corresponding increase in the discharge of the river. This decrease is subsequently seen in observation well CRM-4, municipal well Seminole 10, and to a lesser extent in observation well CRM-3 and the municipal water- treatment plant. A traveltime for water moving from the Cedar Rivet to other sampling sites can be esti mated from the data. A traveltime is estimated Dy determining fiorn the plotted or tabulated data when a change starts in the river and counting the days until correlative changes occur at other at sampling sites.
24 Effect of the Cedar River on the Quality of the Ground-Water Supply for Cedar Rapids, Iowa
i? c & JQ C
Tabl
e 4.
Res
ults
of m
icro
scop
ic p
anic
ulat
e an
alys
is fo
r se
cond
ary
indi
cato
rs in
wat
er fr
om s
tudy
are
a, D
ecem
ber
1992
thro
ugh
Nov
embe
r 19
93[V
alue
s ar
e co
unts
per
100
gal
lons
of
wat
er, e
xcep
t as
not
ed;
1, in
unda
ted
at t
ime
of s
ampl
ing;
ND
, no
t de
tect
ed]
i o =? o a. Dl 31 1 i o 5? Q.
Dl 5f 6 C
Dl
Mun
icip
al w
ell o
r D
ate
sam
plin
g si
te
(mon
th-
(fig
s. 6
and
7)
day-
year
Ced
ar R
iver
12
-07-
9204
-06-
9304
-13-
9304
-26-
9308
-02-
9311
-16-
93
Ced
ar R
apid
s m
unic
ipal
04
-06-
93w
ater
-tre
atm
ent
plan
t 04
-07-
9304
-08-
9304
-26-
93
Spo
res
4.3x
1 02
6.5x
1 03
3.6x
1 03
1.3x
l03
1.4X
104
ND
ND
ND
ND 1
Polle
n
5.6x
l03
1.6x
ll0
4l.
lxlO
49.
3x1
038.
8x1
03N
D 3N
D 3 9
Cru
sta
ce
ans
ND
ND 5.
2xl0
23.
3xl0
2N
DN
D
ND
ND 1
ND
Cru
st
acea
n eg
gs
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
Nem
a-
tode
s
l.lx
lO3
7.3x
1 03
3.6x
1 03
l.Oxl
O3
4.4x
1 03
ND 20 10 3 12
Nem
a-
tode
eg
gs
4.3x
l02
3.8x
1 02
ND
ND
ND
ND 26 17 1
ND
Rot
ifer
s
1.6x
l03
3.8x
l02
l.Oxl
O3
1.7x
l03
1.6x
l03
l.Oxl
O5
1 5 3 92
Rot
ifer
eg
gs
2.1x
l03
3.8x
1 02
2.1x
l04
ND
ND
ND
ND 1
ND
ND
Am
oeba
e
l.lx
lO3
l.lx
lO3
l.Oxl
O3
ND
ND
ND
ND
ND
ND 1
Inve
rte
br
ate
eggs
2.1x
l03
3.8x
l02
5.2x
l02
6.7x
1 02
1.2x
l03
ND
ND 2 1 11
<
Ced
ar R
apid
s m
unic
ipal
wel
lsT>
1 CD 5' (A Dl
D Q. O o D (A
Eas
t 1
04-1
4-93
Eas
t 19
04
-26-
931
Wes
t 6
04-1
5-93
04-2
6-93
ND 3
ND
ND
10 20
1 5
1
ND
ND
ND
ND
ND
ND
ND
ND 1
ND
ND
ND
ND
ND
ND
ND 3
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
2 3
ND 1
Sem
inol
e 2
Sem
inol
e 3
04-1
5-93
1 N
DN
DN
DN
DN
DN
DN
DN
DN
D
04-1
5-93
109
-22-
9311-18-93
3 2 1
7ND
ND
NDND
ND
ND
ND
ND
4ND
ND
NDND
ND
1 1
NF
1ND NF
8ND
ND
2 1
ND
10
Ul
10 <n m
3) IB TJ_
Q.
Tabl
e 4.
Res
ults
of m
icro
scop
ic p
artic
ulat
e an
alys
is fo
r sec
onda
ry in
dica
tors
in w
ater
from
stu
dy a
rea,
Dec
embe
r 19
92 th
roug
h N
ovem
ber
1993
Con
tinue
d
i o M
unic
ipal
wel
l or
3
sam
plin
g si
te
£
(fig
s. 6
and
7)
IB 3i
Sem
inol
e 10
§ o 3 <D O C 2L 31
Sem
inol
e 14
a 1 0 3 c a-
Sem
inol
e 16
1 CO c o
o
Dat
e (m
onth
- da
y-ye
arS
pore
sC
rust
a-
Polle
n ce
ans
Cru
st
acea
n eg
gsN
ema-
to
des
Nem
a-
tode
eg
gsR
otif
ers
Rot
ifer
eg
gsA
moe
bae
Inve
rte
br
ate
eggs
Ced
ar R
iver
mun
icip
al w
ells
C
ontin
ued
12-0
8-92
04-1
3-93
09-2
4-93
11-1
6-93
04-0
6-93
I08
-02-
9311
-16-
93
04-0
6-93
I04
-07-
93 I
08-0
2-93
11-1
6-93
1 2N
DN
D 1N
DN
D 1N
DN
DN
D
1 18 1N
D 1 2N
D 2 6N
DN
D
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND 2 1
ND 1
ND
ND 3 3
ND
ND
ND 1
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND 39 17 ND
ND
ND 2
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
8N
DN
DN
D 1N
DN
D
ND
ND
ND
ND
ND 2
ND
ND
ND
ND
ND 2
ND
ND
ND
O
i
Tabl
e 5.
Res
ults
of
mic
rosc
opic
par
ticul
ate
anal
ysis
for
sele
cted
wat
er-q
ualit
y pr
oper
ties
and
sele
cted
se
cond
ary
indi
cato
rs in
wat
er fr
om s
tudy
are
a, D
ecem
ber
1992
thro
ugh
Nov
embe
r 19
93'[V
alue
s ar
e co
unts
per
100
gal
lons
of w
ater
, exc
ept
as n
oted
; am
orph
ous
debr
is, o
rgan
ic d
etrit
us, a
nd s
and
size
s ar
e gr
eate
r th
an 5
mic
rom
eter
s;
conf
luen
t, la
rge
conc
entr
atio
n of
am
orph
ous
debr
is;
f, si
ze is
1 -5
mic
rom
eter
s; v
f, si
ze is
less
than
1 m
icro
met
er;
I, in
unda
ted
at ti
me
of s
ampl
ing;
N
TU, n
atio
nal
turb
idity
uni
ts; b
egin
/end
, va
lues
at b
egin
ning
and
end
of
sam
ple
colle
ctio
n; N
D, n
ot d
etec
ted;
NS,
not
sam
pled
]
a 5 <D 0) ^ 30 I O 3 I?
<D I I I « 0) 3
Q.
? I I <D
Mun
icip
al w
ell o
r sa
mpl
ing
site
(f
igs.
6 a
nd 7
)C
edar
Riv
er
Ced
ar R
apid
s m
unic
ipal
wat
er-t
reat
men
t pl
ant
Dat
e (m
onth
- da
y-ye
ar12
-07-
9204
-06-
9304
-13-
9304
-26-
9308
-02-
9311
-16-
93
04-0
6-93
04-0
7-93
04-0
8-93
04-2
6-93
Vol
ume
filt
ered
(g
allo
ns)
93 158
130
130
100
150
1,34
3
1,72
047
8
552
Turb
idity
(NTU
)
begi
n
15 48 22 65 85 7.2
4.6
4.7
9.0
2.8
end
12 54 21 66 94 6.4
4.7
9.0 .6
0
3.4
Filte
r co
lor
dark
bro
wn
dark
bro
wn
dark
bro
wn
brow
nbr
own
brow
n
dark
ora
nge
oran
geor
ange
oran
ge
pH (
stan
dard
un
it)
begi
n
8.3
7.7
8.1
8.1
8.0
7.9
7.4
7.5
7.7
7.6
end
8.3
7.8
8.1
8.1
8.2
8.3
7.5
7.7
7.5
7.6
Am
orph
ous
debr
is
conf
luen
tco
nflu
ent
2.4x
1 06
conf
luen
tco
nflu
ent
vf c
onfl
uent
conf
luen
tco
nflu
ent
conf
luen
tco
nflu
ent
Ced
ar R
apid
s m
unic
ipal
wel
ls
Eas
t 1
Eas
t 19
Wes
t 6
Sem
inol
e 2
Sem
inol
e 3
04-1
4-93
04-2
6-93
I
04-1
5-93
04-2
6-93
04-1
5-93
1
04-1
5-93
109
-22-
9311
-16-
93
1,34
2
1,22
2
1,35
81,
196
1,37
7
1,63
33,
388
1,26
1
113 1.
1
1.2 .7
3
.79
.75
.18
.09
8.4
1.4 .7
21.
7 .45
.82
NS
NS
oran
ge
light
tan
peac
hlig
ht ta
n
light
tan
light
tan
light
tan
tan
7.6
7.5
7.6
7.5
7.6
7.6
8.3
7.0
7.4
7.5
7.6
7.5
7.6
7.6
NS 7.
0
conf
luen
t
conf
luen
t
16co
nflu
ent
4.1x
l03
2.7x
l03
conf
luen
t7.
7xl0
2
Tabl
e 5.
Res
ults
of
mic
rosc
opic
par
ticul
ate
anal
ysis
for
sele
cted
wat
er-q
ualit
y pr
oper
ties
and
sele
cted
se
cond
ary
indi
cato
rs in
wat
er fr
om s
tudy
are
a, D
ecem
ber
1992
thro
ugh
Nov
embe
r 19
93 C
ontin
ued
a 5 3 o 3 <D
O m a I o 3 1 (0 I < o o
Mun
icip
al w
ell o
r sa
mpl
ing
site
(f
igs.
6 a
nd 7
)
Dat
e (m
onth
- da
y-ye
ar
Vol
ume
filte
red
(gal
lons
)
Tur
bidi
ty (N
TU)
begi
nen
dFi
lter
colo
r
pH (
stan
dard
un
it)
begi
nen
dA
mor
phou
s de
bris
Ced
ar R
apid
s m
unic
ipal
wel
ls C
ontin
ued
Sem
inol
e 10
Sem
inol
e 14
Sem
inol
e 16
12-0
8-92
04-1
3-93
09-2
2-93
11-1
6-93
04-0
6-93
I08
-02-
9311
-16-
93
04-0
6-93
I04
-07-
93 I
08-0
2-93
11-1
6-93
1,17
81,
380
1,43
01,
163
1,20
01,
265
1,09
2
1,23
51,
340
1,20
01,
133
0.71 1.1 .1
8.1
4
53 8.9
15.8
98 12 17 21
0.
NS 15 2. 12 11 53
,28
,84
,09
,3 ,98
.85
pale
tan
light
tan
light
tan
tan
oran
geor
ange
oran
ge
oran
geor
ange
oran
geor
ange
7 7.8 .8 8.4
7.2
7.5
7.6
7.1
7.3
7 7 7.3 .5 .1
7 7 8 7, 7, 7, 6.8 .8 .3 .1 .4 ,4 .8 7.4
7, 7 6.6 .5 .8
conf
luen
tco
nflu
ent
1.6x
l04
f con
flue
nt
conf
luen
tco
nflu
ent
f con
flue
nt
conf
luen
tco
nflu
ent
conf
luen
tf c
onfl
uent
3D
0) TJ E
(a
C/3 D C/3
LU U C/3
in csi
700
600
500
400
300I-
LU OccLU Q_C/3
C/3 O QC O
200
Note: Breaks in lines indicate no data.
20 25 February
10 15 20 March
25 30
1993
10 15 April
20
700
600
500
400
o
IoQ2 Oo oO 30°LU Q_ C/3
200
Specific conductanceDischarge
80,000
70,000
60,000
50,000
40,000
30,000
20,000
10,000
25 29
-, 80,000
o mD O
25 30 5 10 15 20 25 30June July
1993
5 10 15 20 25 30 August
70,000
60,000 oo
50,000
40,000
30,000
20,000
10,000
Figure 11 . Specific conductance and discharge for the Cedar River at Cedar Rapids gaging station from February 20 through April 29 and June 25 through August 30, 1993.
Specific Conductance
Specific-conductance values for the Cedar River started to decrease on February 28, 1993, with a subse
quent decrease in values at observation well CRM-4 on March 4, 1993, and at municipal well Seminole 10 on March 7, 1993 (fig. 14). Water of lower specific conductance took 4 days to travel to well CRM-4 and
Effect of the Cedar River on Selected Water-Quality Properties and Constituents of the Alluvial Aquifer 29
8.4
8.2
{28.0
7.8
Q DC
g~ 7.6Q.
7.4
7.2
Note: Breaks in lines indicate no dataDischarge
20 25 February
5 10 15 20 March
25 30
1993
10 15 April
20 25 29
80,000
70,000
60,000
50,000
40,000
30,000
20,000
10,000
0
Q Z O o
woc
LU LU U-
oCD D OzLUIDoc<o
Figure 12. pH and discharge of the Cedar River at Cedar Rapids gaging station from February 20 through April 29,1993.
7 days to travel to well Seminole 10. Three other selected events are shown starting on March 5 and October 2, 1993, and January 2, 1994, for the Cedar River. Traveltimes to well CRM-4 were 5, 5, and 4 days for observable changes to start at well CRM-4 and 12, 7, and 9 days to start at well Seminole 10, respectively. Water at observation well CRM-3 had an estimated traveltime of 29 days from the river on February 28, 1993, based on a correlative change that occurred on March 29, 1993 (fig. 15). Water entering
the municipal water-treatment plant generally follows the trend of specific-conductance values for the river, but abrupt changes that occur in the river are not apparent in the water-treatment plant and no corre lation of changes was possible from the data.
PH
There is no obvious correlation between the change in pH of the Cedar River that can be traced
30 Effect of the Cedar River on the Quality of the Ground-Water Supply for Cedar Rapids, Iowa
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D
700Traveltimes
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Note: Breaks in lines indicate no data
Municipal well Seminole 10Observation
well CRM-4
April 1993
June July
| 70° coo ccy 600
U 500
O CJ
y 300 -CJ
Q. CO
Traveltimes 7 days 5 days
Cedar
Observation well CRM-4
Traveltimes 4 days 9 days
Municipal well Seminole 10
200August September October
1993November December January
1994
Figure 14. Specific conductance of water from the Cedar River, observation well CRM-4, and Cedar Rapids municipal well Seminole 10, and estimated traveltimes of water from the river to observation well CRM-4 and municipal well Seminole 10, February 1, 1993, through January 31,1994.
figure 17. Figure 18 ,shows temperature for the Cedar River, observation well CRM-3, and water-treatment plant.
On March 24, 1993, the water temperature increased in the river, and a corresponding increase was observed in observation well CRM-4 on March 31, 1993 (fig. 17). Thus, the traveltime of water from the Cedar River to observation well CRM-4 is esti
mated to be 8 days. Similar estimates of traveltime from the Cedar River to observation well CRM-4 were made for August 27 to September 3, 1993, and from October S to October 15, 1993; both events had travel- times of 7 days. Traveltimes for March 24 to April 11, 1993, August 27 to September 13, 1993, and October 8 to October 18, 1993, ranged from 10 to 17 days. The traveltimes are not long enough to have a substantial
32 Effect of the Cedar River on the Quality of the Ground-Water Supply for Cedar Rapids, Iowa
Municipal water treatment plant
Note: Breaks in lines indicate no data.
Figure 15. Specific conductance of water from the Cedar River, observation well CMR-3, and the municipal water-treatment plant, February 1, 1993, through January 31, 1994.
effect on the viability of Giardia cysts in water pumped by municipal well Seminole 10.
Water temperatures for observation well CRM-3 (fig. 18) do not corollate to the temperatures in the Cedar River. The maximum temperature for water in well CRM-3 was reached on December 2, 1993, at 18.7 °C while the river water was at 0.8 °C.
Water temperature measured at the water-treatment plant (fig. 18) changed slowly from a minimum on April 10, 1993, to a maximum on September 13, 1993. A traveltime is estimated from March 24, 1993, when the water temperature in the river started to warm, to the minimum temperature observed at the water-treatment plant on April 10, 1993 (17 days). Traveltime from the maximum water temperature in the river on August 27, 1993, to the maximum water temperature on September 13, 1993, at the water-treatment plant is also 17 days. This is the same traveltime as the traveltime to municipal well Seminole 10 in April and in August. There were no . rapid changes in water temperature observed at the municipal water-treatment plant.
Dissolved Oxygen
In a stream, dissolved oxygen is a function of
the equilibrium concentration of dissolved oxygen and is controlled mainly by pressure and temperature at the contact between the atmosphere and the water surface (Hem, 1989). Some aquatic organisms require oxygen and may deplete concentrations of dissolved oxygen, whereas other organisms may increase the dissolved- oxygen concentration through photosynthesis. Concentrations of dissolved oxygen in ground water usually are the result of recharge to the aquifer, and concentrations can be similar to those of surface water (Hem, 1989). Dissolved-oxygen concentrations in water from the Cedar River, observation well CRM-4, and municipal well Seminole 10 are shown in figure 19, and in water from the Cedar River, observa tion well CRM-3, and municipal water-treatment plant are shown in figure 20.
Dissolved-oxygen concentrations in water from the Cedar River shows seasonal trends (fig. 19). During the colder winter months, the concentration of dissolved oxygen is about 14 to 15 mg/L. During the summer months, dissolved-oxygen concentrations average 7 to 9 mg/L (table 28). Colder water can hold more dissolved oxygen than warmer water. Diurnal fluctuations were present throughout the study and probably result from biological activity. Dissolved- oxvgen concentrations in water from observation well
Effect of the Cedar River on Selected Water-Quality Properties and Constituents of the Alluvial Aquifer 33
IDQ DC <o
Iz
a
Note: Breaks in lines indicete no data
Februery March April May 1993
June
8.6
8.4
8.2
8.0
7.8
7.6
7.4
7.2
7.0
6.8
Cedar River
Municipal well / Seminole 10 '
/ Observation well CRM-4 '
August September October November December
1993January
1994
Figure 16. pH of water from the Cedar River, observation wells CRM-3 and CRM-4, and Cedar Rapids municipal well Seminole 10, February 1,1993, through January 31,1994.
CRM-4 and CRM-3 and municipal well Seminole 10 are dependent on the biological activity in the alluvial aquifer material and the movement of surface water through the material. The concentration of dissolved oxygen has been found to decrease abruptly in the first 50-65 ft of sediments as a result of mineralization of dissolved organic compounds by microorganisms
(Bourg and Berlin, 1993). This could account for the observed decrease of about 2 to 4 mg/L in the dissolved-oxygen concentration between the river and observation well CRM-4 (fig. 19) throughout the study period.
On March 9, 1993, the decreasing concentration of dissolved oxygen in water from the river ceased and
34 Effect of the Cedar River on the Quality of the Ground-Water Supply for Cedar Rapids, Iowa
26
24
22C/32 2003LU 18 uC/3 1C LU lu LUcc. 14 CD l4LUQ 12
cc
LU Q-
Note: Breaks in lines indicate no data. Traveltimes 7 days 17 days
Cedar River
Traveltimes 7 days 10 days
Municipal well Seminole 10
Observation well CRM-4
Traveltimes 8 days 17 days
M M J 1993
O J 1994
Figure 17. Temperature of water from the Cedar River, observation well CRM-4, and Cedar Rapids municipal well Seminole 10, and estimated traveltimes of water from the river to observation well CRM-4 and municipal well Seminole 10, February 1, 1993, through January 31,1994.
started to increase. This change was observed on March 15, 1993, for observation well CRM-4 and on March 17 for municipal well Seminole 10 (fig. 19). Traveltimes based on these changes were 6 and 8 days, respectively. On November 1, 1993, the river concen tration of dissolved oxygen stopped increasing. This change was observed on November 6, 1993, at well CRM-4 and on November 8, 1993, at well Seminole 10, indicating ground-water traveltimes of 5 and 7 days, respectively.
The concentrations of dissolved oxygen in water from observation well CRM-3 (fig. 20) showed very little change compared with well CRM-4. This could be due to ground water of low concentrations of dis solved oxygen seeping up from a deeper aquifer. No
traveltimes based on dissolved oxygen could be deter mined between the river and well CRM-3.
Dissolved-oxygen concentrations in water from the water-treatment plant show only small changes (fig. 20). There are three peaks shown on the graph (fig. 20) for the water-treatment plant on May 10, June 23, and November 14, 1993, which could be a result of changes in the river on April 17, May 26, and November 1, 1993, respectively. These changes indicate traveltimes from the river to the water- treatment plant of 23, 28, and 13 days, respectively. The larger concentrations between July 17 and August 5, 1993, could be the result of algal growths in the pipe of the aeration tower in which the multiprobe was placed.
Effect of the Cedar River on Selected Water-Quality Properties and Constituents of the Alluvial Aquifer 35
Note: Breaks in lines indicate no data Traveltime 17 days
Municipal water treatment plant
Observation well CRM-3Traveltime
17 days
S O N DI- -5
M
Figure 18. Temperature of water from the Cedar River, observation well CRM-3, and the municipal water-treatment plant, and estimated traveltimes of water from the river to observation well CRM-3, February 1, 1993, through January 31, 1994.
ASSESSMENT OF RELATIVE RISK OF ALLUVIAL AQUIFER TO CONTAMINATION BY PATHOGENS
The above-normal streamflow and precipitation during the study increased the effect of the Cedar River on the alluvial ground-water system and the potential for contamination by a pathogen. The increase in runoff could increase the amount of animal wastes reaching streams that could contribute to increased numbers of biogenic pathogens in the sur face water. Several municipal wells were inundated for considerable periods of time during this study. With wells inundated, there could be a shorter path from the ground surface down to the well screen for biogenic pathogens to travel. However, several of the wells are completed through a silty clay and clay layer in the East Well Field (fig. 3) and a fine sandy silt layer in Seminole Well Field (fig. 5). These layers of rela tively low hydraulic conductivity could help in restric ting the movement of biogenic pathogens through the aquifer to the well.
The dissolved-oxygen data indicate that anaer obic conditions were not present in the alluvial aquifer in the vicinity of observation well CRM-4 and muni
cipal well Seminole 10. This lack of anaerobic condi tions could allow a very active microbiological com munity to develop that could aid in the natural filtra tion process that occurs in the alluvial aquifer. Investi gators are finding that microbial activity and diversity are much greater than once thought in aquifers and that lake bottoms, streambeds, and soil zones are simi lar to the biologically active surface layer, known as the schmutzdecke, in slow, sand-filter systems (Boria and others, 1992). This layer is thought to allow perdi tion to occur as part of the filtering process (Boria and others, 1992). The filtration process itself is complex and involves a combination of straining, interception, sedimentation, Brownian diffusion, hydrodynamic retardation, and surface-interaction forces (Boria and others, 1992). Ground-water supplies in porous-media (sand and gravel) aquifers that induce recharge from surface water through pumping generally can be considered low-risk situations for Giardia contamina tion (Boria and others, 1992).
Data from MPA were used to determine the relative risk factor of water from the municipal wells tested and the raw water prior to treatment at the municipal water-treatment plant. This is done by determining the numerical range of each of the bio-
36 Effect of the Cedar River on the Quality of the Ground-Water Supply for Cedar Rapids, Iowa
oc
ocLU Q.(Si
axoQ
O (Si (Si
Note: Breaks in lines indicate no data.
Traveltimes 7 days 5 days
Traveltimes 8 days 6 days
Municipal well Seminole 10
Observation well CRM-4
M
Figure 19. Concentrations of dissolved oxygen in water from the Cedar River, observation well CRM-4, and Cedar Rapids municipal well Seminole 10, and estimated traveltimes for water from the river to observation well CRM-4 and municipal well Seminole 10, February 1, 1993, through January 31, 1994.
16
14 ocLU
zb 12LU-IOcc >uj 10
O(Si
Note: Breaks in lines indicate no data.
Cedar River
Municipal water treatment plant
Observation well CRM-3
D | J 1994
Figure 20. Concentrations of dissolved oxygen in water from the Cedar River, observation well CRM-3, and the Cedar FJapids municipal water-treatment plant, February 1, 1993, through January 31, 1994.
Assessment of Relative Risk of Alluvial Aquifer to Contamination by Pathogens 37
Table 6. Risk of surface-water contamination as determined by microscopic participate analysis of water in the study area, December 1992 through November 1993[Information provided by Tom Noth of the Cedar Rapids Municipal Water Department]
Municipal wells or sampling site (figs. 6 and
Cedar River
Cedar Rapids municipal water-treatment plant
Date (month-day-
7) year)
12-07-92 04-06-93 04-13-93 04-26-93 08-02-9311-16-93
04-06-93 04-07-93 04-08-9304-26-93
Risk factor
77 57 37 37 1874
21 21 1517
Risk of surface- water
contamination
High risk High risk High risk High risk Moderate riskHigh risk
High risk High risk Moderate riskModerate risk
Cedar Rapids municipal wells
East 1
East 19
West 6
Seminole 2
Seminole 3
Seminole 10
Seminole 14
Seminole 16
04-14-93
04-26-93
04-15-9304-26-93
04-15-93
04-15-93 09-22-9311-16-93
12-08-9204-13-9309-22-9311-16-93
04-06-9308-02-9311-16-93
04-06-9304-07-9308-02-9311-16-93
4
5
44
4
21 109
0102
10
149
4
141494
Low risk
Low risk
Low riskLow risk
Low risk
High risk Moderate riskLow risk
Low riskModerate riskLow riskModerate risk
Moderate riskLow riskLow risk
Moderate riskModerate riskLow riskLow risk
38 Effect of the Cedar River on the Quality of the Ground-Water Supply for Cedar Rapids, Iowa
indicators tabulated in table 33 for a particular sample from tables 3 and 4. A rating of extremely heavy (EH), heavy (H), moderate (M), rare (R), or not significant (NS) is assigned to each bio-indicator of the sample. A numerical value then is assigned from table 34 for each bio-indicator according to its rating, and a sum is determined for the numerical values. A relative risk factor is determined from the scale at the bottom of table 34. A detailed explanation of the procedure is described in U.S. Environmental Protection Agency (1989).
Following this procedure, the river was eval uated to be at high risk (table 6) for the period of study due to the presence of Giardia cysts and Cryptospori- dium oocysts and large counts of algae, diatoms, and rotifers (table 3 and 4). Of the eight municipal wells tested during the April 1993 flooding, municipal well Seminole 3 had a high-risk factor, three other wells had a moderate-risk factor, and four wells had a low- risk factor (table 6). Five of the eight wells were inun dated during this time (table 4), one at high risk, two at moderate risk, and two at low risk. For the remainder of the study period two wells had a moderate-risk factor at different times, and the rest of the wells sampled had a low-risk factor.
To measure the efficiency of the filtering process of the alluvial aquifer a log-reduction rate is used (Clancy, 1992). Using the particulate concentrations in table 4 for the wells and the river at concurrent times, a log-reduction rate can be calculated (table 7). The log- reduction rate is calculated for an indicator by taking the log of the number of counts for the surface-water source (surface water) minus the log of the number of counts for the well. The log-reduction rate was calcu lated for vegetative debris, diatoms, and algae. Indica tors that were not detected in both ground water and surface water were not used. If a ground-water sample had no detection for one of the indicators tested, a value of 1 was assumed to calculate the log-reduction rate.
The data for selected municipal wells tested show at least a three-log (99.9-percent) reduction be tween the river and the wells (table 7). A three-log (99.9-percent) reduction of algae is likely to achieve a three-log (99.9-percent) reduction in Giardia cysts (Boria and others, 1992). The log reduction for algae for municipal well Seminole 3 was 4.3 when it recei ved ite high-risk rating on April 15, 1993. To date (1994), there has been no record of an outbreak of waterborne disease in the City of Cedar Rapids (John
North, City of Cedar Rapids Water Department, oral commun., 1994). A three-log (99.9-percent) reduction is required by the USEPA and the Iowa Department of Natural Resources for filtration and disinfection (U.S. Environmental Protection Agency, 1989; Iowa Administrative Code, 1992). The log-reduction data obtained in this study show that the natural filtration of the alluvial aquifer is very effective.
The presence of algae in some of the wells could indicate an inadequate surface seal around the casing. Another possibility could be macropores caused by tree roots, which could enhance vertical seepage to the aquifer from flooded areas. Municipal wells Seminole 14 and 16 are near heavily wooded areas. The count of algae detected at the water-treatment plant in April 1993 was higher than at all of the eight wells sampled during April 1993 (table 3). Some of the wells tested had counts of less than 20 per 100 gal. Because the water sampled at the water-treatment plant is a mixture of water from many wells, the count of algae might be expected to be lower than the results from most individual wells, but this is not the case. Algae growing inside the pipe of the aeration tower, where the sample was collected, could be one explanation. The log reduction for the municipal water-treatment plant compared to the river water was less than three for 3 of 4 samples of algae and 2 of 4 samples of vegetative debris.
Counts of protozoa in samples are similar to those for algae. Large counts are found in the river with smaller counts for the wells and water-treatment plant. Larger counts were measured during the flood ing in March of 1993 than at other times of the year.
SUMMARY
Alluvial aquifers adjacent to large streams are important sources of water for many municipalities. Alluvial aquifers can have large transmissivities and hydraulic conductivities, which make them very desir able for water supply because large amounts of water can be withdrawn. The Surface Water Treatment Rule under the 1986 Amendment to the Clean Water Act requires that public-water supplies be evaluated for susceptibility to surface-water effects (U.S. Environmental Protection Agency, 1989). The ground- water source is evaluated for biogenic material and monitored for selected water-quality properties and constituents to determine the effect of surface water on the water supply.
Assessment of Relative Risk of Alluvial Aquifer to Contamination by Pathogens 39
s I a 2 < o 3 O O
Tabl
e 7.
Filt
ratio
n ef
ficie
ncy
calc
ulat
ed a
s a
log-
redu
ctio
n ra
te b
etw
een
the
Ced
ar R
iver
and
sel
ecte
d m
unic
ipal
wel
ls a
nd
the
Ced
ar R
apid
s m
unic
ipal
wat
er-tr
eatm
ent p
lant
, D
ecem
ber
1992
thro
ugh
Nov
embe
r 19
93I V
alue
s ar
e co
unts
per
100
gal
lons
of w
ater
; lo
g-re
duct
ion
rate
is th
e lo
g of
the
valu
e fo
r gr
ound
wat
er m
inus
the
log
of
the
valu
e fo
r su
rfac
e w
ater
; SW
, sur
face
wat
er;
GW
, gr
ound
wat
er;
ND
, not
det
ecte
d]
3
Q.
ID
(O o o o 0>
Q.
ID ID a O
Mun
icip
al w
ell o
r w
ater
-tre
atm
ent p
lant
(f
igs.
6 a
nd 7
)
Se
min
ole
2
Sem
inol
e 3
Sem
inol
e 10
Sem
inole
l4
Se
min
ole
16
'
Wat
er-t
reat
men
t pla
nt
Da
te
(mo
nth
-
da
y-ye
ar)
04-1
5-9
3
04-1
5-9
3
11-1
6-93
12-0
7-92
04-1
3-9
3
11-1
6-93
04-0
6-9
3
08-0
2-9
3
11-1
6-93
04-0
6-9
3
04-0
7-9
3
08-0
2-9
3
11-1
6-93
04-0
6-9
3
04-0
7-9
3
04-0
8-9
3
04-2
6-9
3
Vegeta
tive d
ebris
SW
l.Oxl
O3
l.Oxl
O3
ND
l.Oxl
O3
l.Oxl
O3
ND
l.lx
lO3
ND
ND
l.lx
lO3
l.lx
lO3
ND
ND
l.lx
lO3
l.lx
lO3
l.lx
lO3
l.Oxl
O3
GW
ND
ND
ND 1
ND
ND
ND
ND
ND
ND
ND
ND
ND 2
ND
ND 4
^ °
9:
Dia
tom
s re
du
ctio
nra
te
3.0
3.0
3.0
3.0
3.0
3.0 3.0
2.7
3.0
3.0
2.4
SW
5.1
xl0
5
5.1
xl0
5
3.3
xl0
3
1.2
xl0
4
5.1
xl0
5
3.3
xl0
3
5.7
xl0
5
ND
3.3
xl0
3
5.7x
1 05
5.7x
1 05
ND
ND
5.7x
1 05
5.7x
1 0
5
5.7x
1 0
5
2.7x
1 0
3
GW
ND 8 ND
ND 2 ND
ND
ND
ND
ND
ND
ND
ND 1 1
ND
ND
Lo
g-
A,
ae
Log
reduct
ion
reduct
ion
rate
5.7
4.8
3.5
4.0
5.4
3.5
5.8
3.5
5.8
5.8
3.5
5.8
5.8
5.8
3.4
SW
3.4
xl0
7
3.4
xl0
7
6.0x
1 07
7.4
xl0
6
3.4
xl0
7
6.0x
1 07
l.Sxl
O7
2.3
xl0
5
6.0x
1 07
l.Sxl
O7
l.Sxl
O7
2.3x
1 05
6.0x
1 07
l.Sxl
O7
l.Sxl
O7
l.Sxl
O7
1.6x
l07
GW 8
1.9x
l03
35 8 9 25
4.0
xl0
3
34 2
3.7
xl0
3
1.6x
l04
47 2
7.9x
1 04
1.9x
104
2.7
xl0
42.
7x1
04
rate
6.6
4.3
6.2
6.0
6.6
6.4
3.7
3.8
7.5
3.7
3.1
3.7
7.5
2.4
3.0
2.8
2.8
The City of Cedar Rapids uses the alluvial aqui fer adjacent to the Cedar River for its drinking-water supply. The alluvial aquifer is hydraulically connected to the Cedar River, bedrock, and upland areas in the study area. The city has three well fields in use along the Cedar River (figs. 6 and 7) with a total of 53 municipal wells (table 2). The three well fields all have a similar lithologic sequence and hydraulic properties. A multiprobe instrument was used to continuously monitor water levels and selected water- quality properties and constituents in the Cedar River, observation wells CRM-3 and CRM-4, municipal well Seminole 10 (fig. 9), and selected water-quality pro perties and constituents at the municipal water- treatment plant (fig. 6).
Selected water-quality properties and constitu ents of the river changed inversely with changes in river stage or discharge (Schulmeyer, 1991). Selected water-quality properties and constituents of the allu vial aquifer changed as water flowed from the Cedar River to municipal well Seminole 10 as a result of drawdown. The values of specific conductance, pH, temperature, and dissolved oxygen for observation well CRM-4 and municipal well Seminole 10 gener ally follow the trends of values for the Cedar River. Values of specific conductance, pH, temperature, and dissolved oxygen at observation well CRM-3 and the municipal water-treatment plant show very little correlation with values for the Cedar River. The traveltime of water through the aquifer could be an indication of the susceptibility of the aquifer to surface-water effects. Estimated traveltimes from Cedar River to municipal well Seminole 10 ranged from 7 to 17 days. The data indicate that ground water has a short residence time in the aquifer before it is pumped out for consumption. Traveltimes were not long enough to have a substantial effect on the viability of Giardia cysts.
The above-normal conditions of streamflow and precipitation present during the study could have in creased the effect that the Cedar River had on the allu vial aquifer and the possibility of contamination by a pathogen. The dissolved-ox.ygen data indicate that an aerobic conditions are not present in the alluvial aqui fer in the vicinity of observation well CRM-4 and mu nicipal well Seminole 10. This lack of anaerobic con ditions could allow a very active microbiological com munity to develop, which could aid in the natural filtration process that occurs in the alluvial aquifer. Microscopic particulate data were collected using the
method outlined by the USEPA to determine if a ground-water source is GWUDI according to the SWTR (Vasconcelos and Harris, 1992). Analysis of 29 samples found no Giardia cysts or Crytosporidium oocysts in water collected from municipal wells and the municipal water-treatment plant.
Data from the MPA were used to determine the relative risk factor of the ground-water source and the log-reduction rate, a measure of the efficiency of the filtering process of the alluvial aquifer. Using MPA data it was determined that, of the eight municipal wells tested during the April 1993 flooding, one muni cipal well, Seminole 3, had a high-risk factor, three other wells had a moderate-risk factor, and four wells had a low-risk factor. Data indicate that the aquifer is filtering out large numbers of algae, diatoms, rotifers, and nematodes as well as filtering out Cryptospori- dium, Giardia and other protozoa. The filtering effi ciency of the aquifer is equivalent to a 3 log-reduction rate or 99.99-percent reduction in particulates.
REFERENCES CITED
Boria, W.T., Wilson, M.P., and Gollnitz, W.D., 1992,Natural filtration in porous media aquifers: American Water Works Association, Proceedings, Water Quality Technology Conference, November 15-19, Toronto, Ontario, p. 1871-1888.
Bourg, A.C.M. and Berlin, C., 1993, Biogeochemicalprocesses during the infiltration of river water into an alluvial aquifer: Environmental Science and Technology, v. 27, no. 4, p. 661-666.
Clancy, J.L., 1992, Interpretation of microscopic particulate analysis A water quality approach: American Water Works Association Water, Proceedings, Quality Technical Conference, November 15-19, Toronto, Ontario, p. 1831-1847.
Freeze, R.A., and Cherry, J.A., 1979, Groundwater: Englewood Cliffs, N.J., Prentice Hall, 604 p.
Hansen, R. E., 1970, Geology and ground-water resources of Linn County, Iowa: Des Moines, Iowa Geological Survey Water-Supply Bulletin 10, 66 p.
Heath, R. C., 1987, Basic ground-water hydrology: U.S. Geological Survey Water-Supply Paper 2220, p. 60-61.
Hem, J.D., 1989, Study and interpretation of the chemical characteristics of natural waters (3d ed.): U.S. Geological Survey Water-Supply Paper 2254, 263 p.
Hydrolab Corporation, 1991, DataSonde@3, Multipara- meter water quality datalogger Operating manual: Austin, Texas, Hydrolab Corporation, 83 p.
References Cited 41
Iowa Administrative Code, 1992, Water supplies Design and operation: Des Moines, Iowa, Environmental Protection[567], chap. 43, v. XI, IAC 10/14/92, 30 p.
Iowa Department of Environmental Quality, 1976, Water quality management plan, Iowa Cedar River basin: Des Moines, Planning and Analysis Section, Water Quality Management Division, 376 p.
Last, M.D., 1994, Giardia and Cryptosporidium flood connection?: Lab Hotline, Hygienic Laboratory, The University of Iowa, v. 32, no. 10, p. 1-2.
Prior, J.C., 1991, Landforms of Iowa: Iowa City, University of Iowa Press, 153 p.
Reading, H. G., 1978, Sedimentary environments and facies: Oxford, England, Blackwell Scientific Publications, 34 p.
Schneider, Robert, 1962, An application of thermometry to the study of ground water: U.S. Geological Survey Water-Supply Paper 1544-B, 16 p.
Schulmeyer, P.M., 1991, Relation of selected water-quality constituents to river stage in the Cedar River, Iowa: U.S. Geological Survey Toxic Substances Hydrology Program, Proceedings of the Technical Meeting, Monterey, California, March 11-15, 1991, p. 227-231.
Southard, R. E., Sneck-Fahrer, D., Anderson, C.J., Goodrich, R.D., and German, J.G., 1994, Water resources data, Iowa, water year 1993: U.S. Geological Survey Water-Data Report, IA-93-1, 388 p.
Squillace, P. J., Liszewski, M. J., andThurman, E. M., 1993, Agricultural chemical interchange between ground water and surface water, Cedar River Basin, Iowa and Minnesota A study description: U.S. Geological Survey Open-File Report 92-85, p. 26.
U.S. Department of Agriculture, 1976, Iowa-Cedar Rivers basin study: Des Moines, Iowa, 250 p.
U.S. Environmental Protection Agency, 1989, Guidance manual for compliance with the filtration and disinfection requirements for public water systems using surface water sources: Washington, D.C., 400 p.
Vasconcelos, Jay, and Harris, Stephanie, 1992, Consensus method for determining groundwaters under the direct influence of surface water using microscopic particu- late analysis: Washington, D.C., U.S. Environmental Protection Agency, 52 p.
Wahl, Ken, and Bunker, B. J., 1986, Hydrology of carbo nate aquifers in southwestern Linn County and adjacent parts of Benton, Iowa and Johnson Counties, Iowa: Des Moines, Iowa Geological Survey Water Supply Bulletin 15, 56 p.
Wilson, M.P, Gollnitz, W.D., and Boria, W.T., 1992, Temporal concepts in ground water transmission of Giardia cysts and other microscopic particulates: American Water Works Association, Proceedings, Water Quality Technology Conference, November 15-19, Toronto, Ontario, p. 1859-1869.
42 Effect of the Cedar River on the Quality of the Ground-Water Supply for Cedar Rapids, Iowa
Table 8. Mean daily water levels in the Cedar River at the surface-water monitoring site, February 1, 1993, through January 31, 1994[Water levels given in feet above sea level; . no data]
Day
12345
6789
10
1112131415
1617181920
2122232425
262728293031
MeanMaximumMinimum
Feb.
717.07717.20
717.18717.32717.22
717.04716.78716.95716.88717.23
717.78717.19717.06717.16
_
_
716.65716.55
717.08717.78
716.55
Mar.
716.35716.09717.97720.74721.44
721.52722.06723.01722.24721.02
720.87719.41717.72717.64717.02
716.76718.26718.70718.17717.87
717.68717.85718.65717.63718.85
719.79720.22720.68721.41722.41723.70
719.47723.70
716.09
Apr.
725.25727.56730.14730.49729.35
727.28724.74722.90
721.75
721.52721.90721.83721.40720.76
720.81721.22721.17721.16722.61
722.88722.34722.21723.21724.85
724.61722.94721.79720.84720.25
723.44730.49
720.25
May
719.90719.65720.19719.93720.52
720.88721.78722.21722.12721.74
721.36720.73720.67720.58720.91
720.89720.30
718.23717.84717.97718.15
717.96717.71718.00718.36717.94718.03
719.80722.21
717.71
June
717.93718.08718.70719.25719.74
719.92719.94720.14720.89721.66
722.65723.49723.33722.81722.16
721.28720.86720.98721.36722.73
722.44723.22724.13724.66724.35
722.98721.42720.40719.74720.38
721.39724.66
717.93
July
720.60720.46720.49721.08723.01
722.40721.02720.69723.05724.90
726.42727.14725.55724.88725.33
725.33725.08727.09725.88724.44
724.35724.5 1723.76722.59721.26
720.39719.73720.13720.72-720.68720.69
723.02727.14
719.73
Aug.
721.79720.86720.36720.69720.82
720.97720.41719.43719.02722.40
720.72719.45719.59720.33721.53
721.90722.64722.10723.75726.00
727.02725.74724.63724.05723.51
723.17723.41722.50722.13721.47721.65
722.07727.02
719.02
Sept.
721.57721.33721.40720.99720.60
720.04719.48718.88718.32718.47
718.15717.58717.59718.06718.76
718.79718.77719.05719.05718.66
718.74718.58718.60718.22717.97
718.49718.57718.44718.33717.69
718.97721.57
717.58
Oct.
717.26717.48717.16717.00717.24
717.00716.78716.56717.12
717.85
717.84717.59717.57717.38717.17
717.03717.02717.19717.21717.00
717.16717.34717.10716.82716.74
716.83716.69716.26717.04717.23717.23
717.13717.85
716.26
Nov.
717.28717.19716.86716.53716.83
717.15717.05717.20717.34717.24
716.94716.79716.59716.88717.24
717.26717.23717.02716.81716.97
716.88717.10716.92717.10717.14
717.03716.79716.79717.07717.88
717.04717.88
716.53
Dec.
718.56717.32716.97716.64716.50
716.80716.82716.80716.42716.58
717.05716.54716.42716.52716.68
716.90716.78
716.71716.67
716.52716.65717.89718.74718.10
717.90718.32718.53718.44718.54718.35
717.26718.74
716.42
Jan.
718.34718.84718.80718.80718.56
718.38718.51718.45718.43718.15
718.33718.05717.94718.05718.15
717.67717.65717.84717.74717.95
717.67717.44717.26717.28717.29
717.35716.92716.95717. 20717. 67717.55
717.91718.84
716.92
Mean Daily Water Levels in Cedar River 43
Table 9. Mean daily water levels in observation well CRM-4, February 1,1993, through January 31,1994[Water levels given in feet above sea level; , no data]
Day
12345
6789
10
1112131415
1617181920
2122232425
262728293031
MeanMax
Fab. Mar. Apr. May
717.33 ... ... 718.26717.45 ... ... 717.98717.44 ... ... 718.42717.55 ... ... 718.16717.43 ... ... 718.70
717.26 719.03717.00
717.17 ......
_ . _ _ ...
719.22719.10 719.53
719.13 719.51718.89718.16717.71717.30
717.01716.70716.29716.42716.62
717.14 ... 716.44
717.53 716.22718.03 716.49718.80 716.82
718.73 716.39716.48
717.33 717.87 718.99 717.61717.55 718.80 719.13 719.53
June
716.40716.47717.13717. 67718.19
718.44 ...
719.16...
...
...
...
...
...
_... ......
_ .........
...
...
...
719.22......
717.83719.22
July Aug. Sept.
...
...719.42 719.69
...
719.32718.84718.42717.80717.84
717.44716.82716.77717.39717.86
717.94717.90718.12718.13717.73
717.52717.13717.14716.97716.80
717.24719.15 717.30719.37 717.19
717.14716.56
...
719.26 719.55 717.57719.37 719.69 719.32
Oct.
716.38716.57716.22716.05716.24
715.97715.76715.55716.06...
_......
716.48716.27
716.09716.07716.21716.23716.03
716.16716.19715.87715.60715.51
715.66715.76715.66716.36716.49716.47
716.07716.57
Nov.
716.49716.39716.08715.56715.60
715.88715.74715.90715.68715.23
714.94714.77714.38714.70715.04
715.09715.32715.14714.87714.97
714.73714.95714.76714.94714.94
714.81714.54714.53714.78715.40
715.20716.49
Dec.
715.99715.05714.71714.34714.10
714.37714.38714.60714.31715.97
716.41715.90715.80715.90716.06
716.27716.17716.11716.11716.05
714.63713.90714.75715.73715.41
715.17715.66715.82715.70715.76715.55
715.38716.41
Jan.
715.51715.99716.04...
715.97
715.77715.99715.78715.73715.43
715.63715.35715.24715.38715.54
715.00715.01... ...
_
714.41714.19714.30714.38
714.36713.92713.92714.17714.60714.59
715.08716.04
imumMini 717.00 717.14 718.73 716.22 716.40 719.15 719.42 716.56 715.51 714.38 713.90 713.92mum
44 Effect of the Cedar River on the Quality of the Ground-Water Supply for Cedar Raplde, Iowa
Table 10. Mean daily water levels in municipal well Seminole 10, February 1, 1993, through January 31, 1994[Water levels given in feet above sea level; , no data]
Day
12
3
4
5
6
78
9
10
11
12
1314
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
3031
MeanMaximumMinimum
Feb.
__
...
_._
715.73
709.21
699.76
699.41
699.46
699.39
699.18
709.77
714.80
714.23
714.11
696.82
697.00
697.61
697.64
697.31
697.52
703.47
715.73
696.82
Mar.
__
...698.43
700.82
701.79
701.89
702.13
702.70
702.85
703.05
702.90
701.67
700.27
699.81
699.06
698.68
699.49
699.93
699.36
699.03
698.82
699.04
699.78
699.04
699.74
698.72
700.37
703.05
698.43
Apr.
...
...
...
703.55
703.33
703.82
703.98
703.66703.19
703.26
703.74
703.66
703.82
703.85
703.74
703.76703.29
704.27
705.72
705.77
704.38703.77
703.08
702.67
703.82
705.77
702.67
May
702.35
702.12
702.49
702.31
702.83
703.13
718.19
722.10
722.05
721.74
721.29
718.18
714.06
705.59
705.76
705.87
705.68
705.32
705.09
704.73
704.49
703.95
703.49
703.93
704.16
704.02
703.88
704.04
704.24
703.84
704.08
707.58
722.10
702.12
June
704.16
704.08
704.90
705.43
706.23
706.69
711.52
716.53
704.85
705.62
706.4 1
717.59
723.01
722.29
721.51
712.83
706.72
708.41
708.54
709.52
709.38
710.14
710.89
711.42
711.16
709.97
708.81
707.97
707.32
710.13
723.01
704.08
July
710.06
719.49
720.03
722.03
721.41
720.02719.71
721.96
723.89
725.38
726.11
724.49
723.87724.31
724.27
724.02
726.02
724.81
717.80
713.79
712.27
711.73
710.47
709.43
708.83
708.46
709.04
709.70
709.47
709.28
717.74
726.11
708.46
Aug.
710.31
709.57
709.17
709.37
709.47
709.53
715.74720.12
713.71
716.20
711.45
712.82
716.85
7 1 1 .73
721.69
715.55
711.19
711.13
712.67
715.14
715.65
714.68
713.75
713.38
713.06
712.71
712.97
712.17
711.83
711.13
711.32
713.10
721.69
709.17
Sept.
711.40
711.13
711.15
710.61
710.29
708.66
708.55
708.86
708.30
708.24
707.84
707.19
706.87
708.99
708.43
709.19
708.97
709.16
709.15
708.82
707.70
706.43
706.45
705.72
705.23
705.76
705.78
705.48
705.45
705.44
708.04
7 1 1 .40
705.23
Oct.
705.74
705.90
705.5 1
705.35
705.62
705.19
704.88704.74
705.25
705.77
705.89
705.78
705.87
705.63705.34
705.06
705.05
705.13
705.20
704.94
705.10
705.09
704.80
704.63
704.55
704.61
704.54
703.90
704.26
704.33
704.32
705.10
705.90
703.90
Nov.
704.37
704.36
704.03
703.57
703.70
703.80
703.55703.73
703.82
703.65
703.46
703.23
702.57
702.54
702.89
703.24
703.72
703.57
703.09
703.20
703.04
703.56
703.35
703.56
703.33
703.20
703.02
702.97
703.15
703.61
703.43
704.37
702.54
Dec.
704.05
703.22
702.95
702.42
702.21
702.53
702.67
704.36
704.69
715.52
716.01
715.45
715.34
715.42
715.66
715.87
715.78
715.75
715.82
715.79
706.36
700.57701.39
702.40
700.87
700.71
702.16
702.28
702.09
701.95
701.33
707.21
716.01
700.57
Jan.
701.27
701.80
702.17
702. 1 1
701.86
702.63
701.27
701.14
700.87
701.35
701.14
701.09
701.48
702.02
701.18
_
698.94
698.63
699.29
699.96
699.37
698.96698.87
699.17
699.57
700.02
700.65
702.63
698.63
Mean Daily Water Levels in Municipal Well Seminole 10 45
Table 11. Mean daily water levels in observation well CRM-3, February 1, 1993, through January 31, 1994[Water levels given in feet above sea level; , no data]
Day
1234
5
6789
10
1112131415
1617181920
2122232425
262728293031
MeanMaximumMinimum
Feb.
...
...
...
...
...
_.........
716.51
716.33715.07714.93714.99714.89
714.75715.72716.18716.15716.02
714.18714.50714.80714.79714.42
714.70 ...... ...
715.23716.51
714.18
Mar.
...
...715.38718.27...
_...
721.00720.49719.39
719.49718.30716.72716.19715.47
715.20716.28...
715.91
715.68715.69716.61715.86...
_
718.15718.65719.43720.56722.21
717.77722.21
715.20
Apr.
724.21726.68729.22729.55728.48
726.49723.94722.02...
720.88
720.59721.00720.96720.51719.94
719.98720.31720.24720.27721.56
721.91721.47721.33722.34724.03
723.88722.29721.16720.26719.57
722.59729.55
719.57
May
719.11718.80719.21718.95719.52
719.86721.72722.62722.61722.26
721.85721.15720.73719.92720.22
720.21719.61719.01718.74718.35
718.07717.68717.27717.38717.56
717.39717.17717.40717.70717.32717.38
719.25722.62
717.17
June
717.33717.37717.90718.37718.85
719.10719.51720.17719.94720.82
721.88723.71724.03723.53722.94
721.44720.49720.63720.97722.21
722.08722.96723.91724.50724.18
722.84721.45720.37719.71720.19...
721.11724.50
717.33
July
720.35720.17720.33720.90722.88
722.36721.03720.66722.79724.70
726.24727.00725.39724.68725.18
__
724.81726.86725.66724.27
724.21724.28723.53722.38721.18
720.39719.63719.84720.28720.24720.18
722.75727.00
719.63
Aug.
721.16720.37719.93720.16720.24
720.30720.40720.12719.15721.94
720.35719.49719.84719.82721.59
721.55721.97721.48723.08725.40
726.47725.13724.02723.55723.13
722.71723.02722.13721.71721.07721.11
721.69726.47
719.15
Sept.
721.06720.80720.87720.47720.17
719.59719.07718.61717.95717.84
717.33716.74716.73717.27717.73
717.78717.72717.91717.93717.58
717.48717.17717.19717.11717.01
717.42717.50717.48717.50716.99 .
718.13721.06
716.73
Oct.
716.55716.76716.34716.15716.31
716.06715.86715.64716.10716.80
716.91716.81716.68716.27716.08
715.90715.88715.99716.02715.83
715.96716.00715.73715.47715.39
715.50715.59715.05715.44715.57715.55
716.01716.91
715.05
Nov.
715.58715.50715.22714.59715.12
715.41715.30715.43715.45715.19
714.83714.68714.38714.66715.03
715.08715.14714.80714.49714.57
714.37714.57714.49714.76714.77
714.63714.37714.36714.60715.17...
714.88715.58
714.36
Dec.
715.74
715.00
714.62
714.26
714.02
714.24
714.18
714.35
714.00
715.19
715.64
715.15
715.03
715.15715.31
715.50
715.43...
715.46
715.33
714.76714.27
715.07
716.11
715.86
715.58
715.98
716.11
715.98
716.04
715.86
715.17716.11
714.00
Jan.
715.82716.26716.32...
716.28
716.09716.26716.12716.05715.78
715.91715.66715.56715.67715.82
715.33715.33715.45715.29715.43
__
714.65
714.46
714.54
714.62
714.61
714.18
714.23
714.45
714.89
714.84
715.38
716.32
714.18
46 Effect of the Cedar River on the Quality of the Ground-Water Supply for Cedar Rapids, Iowa
Table 12. Water-level measurements for observation wells CRM-3, CRM-4, and CRM-6, February 1993 through January 1994[Water-level measurements, in feet above sea level, made using a steel tape and measured to 0.01 ft; . no data]
Date (month-day-
year)
02-04-9302-09-93 '02-11-9302-1 8-93 '03-02-93
03-18-9303-25-9304-09-9304-23-9306-03-93
06-16-9307-01-9308-24-9309-10-9310-12-93
10-13-9310-28-9311-04-9311-09-9311-23-93
1 2-06-931 2-20-93 '01-04-9401-21-9402-19-94
Observation
Time (24-hour)
1350
14251510
12551145153014151350
1220131011351120
12151145123012351130
13051200114514000830
well CRM-3
Water level
717.49
716.36714.73
716.43717.35722.14722.30718.53
721.33720.98724.47718.80
717.40716.47716.21716.00715.59
715.17716.62717.06715.26715.60
Observation
Time (24-hour)
15101100145513101310
11350855152212351140
11151115091509050850
10150955120010250950
10251100104513300830
well CRM-4
Water level
717.46716.80716.11716.93714.54
716.31717.24721.46721.67718.09
721.00720.70724.22718.57717.19
716.95716.04715.86715.58715.35
714.88717.12716.69714.86715.47
Observation well CRM-6
Time Water (24-hour level
_
___
___ _...
0856 720.78
_ _
0930 721.06 ___
0830 719.92
Municipal well Seminole 10 was not operating on this day.
Water-Level Measurements for Observation Wells 47
Table 13. Mean daily specific conductance of water from the Cedar River, surface-water monitoring site, February 1, 1993, through January 31, 1994[Specific conductance given in microsiemens per centimeter at 25 degrees Celsius; , no data]
Day
l2345
678
910
11
12131415
1617181920
2122232425
262728293031
Mean
MaximumMinimum
Feb.
640631635625594
595596595592571
500553576583
_...
...
__
636638
597640
500
Mar.
636627408237223
238260274281283
280290369406437
486454403
366
433443343401
323
285283261238227240
348636
223
Apr.
251237229237262
310368414
434
446455458464472
471468471462437
446447436400380
408451479496487
406496
229
May
467468432452452
450408411433
446
456465462450448
459471
549553557559
563560553537545550
487563
408
June
555555533506508
516521491454416
389405430460478
483482481442388
402385376387415
461
497518530460
464
555
376
July
434438411409
380
411464477358273
249262314331342
367392355372388
380396424466500
519526496458462476
404526
249
Aug.
397436454445434
437480518527
348
408488481411379
391370404337286
314365384397421
401408452450454435
417527
286
Sept.
433440473487502
521535541544
540
535539540523502
503517500473486
499512526544549
528529539556563
516563
433
Oct.
565565562554536
525517507499
479
482505514519525
533538542
543550
549545540536527
523527526532536539
530565
479
Nov.
541543547
554559
562563567
565562
561561560559553
554556561562563
563563569575574
573572569569575
562575
541
Dec.
576578583586589
588582582
580576
571572573570567
573572
567561
554556568589600
609612619619625626
584626
554
Jan.
628632627620610
600600604609616
615607603604604
603606611614614
616609603597
593
591590591591585586
606632
585
48 Effect of the Cedar River on the Quality of the Ground-Water Supply for Cedar Rapids, Iowa
Table 14. Mean daily specific conductance of water from observation well CRM-4, February 1, 1993, through January 31, 1994[Specific conductance given in microsiemens per centimeter at 25 degrees Celsius; , no data]
Day
1234
5
67
8
910
11121314.
15
16
17
18
1920
21
22
23
24
25
26272829
30
31
MeanMaximumMin-mum
Feb.
581581585594604
612618623...
625
628628618582539
560574
584593590
596611627
655658
654651.........
607
658
539
Mar.
...644
645
624
464
330
291
275272
279286292303
314
330363
415
446
479
497469
408
391418
452415415381351342
400645
272
Apr.
332312300287283
283285293...
294
321388450478488
488.........
_...
467
466
453426404
417
438
380488
283
May
453
469480485477
460472
474
476
479
477
476
476
479
475
478
471
482505516
526534539542544
543543543546
545
542
500546
453
June
530532538546548
536516507
510516
493470467
462
458
450421406445
478
478
471
439
413
411
403
395404439486
472
548
395
July
511523......
...
...
...
...
...
...
518
510
504503503493
442
438429
390392
409453493
502478
447
470
523
390
Aug.
443
466
414
405
439
439435436
437
429
430480490379373
387431432
388361
387387345
315
323
355380394415412
410
407
490
315
Sept.
444
447
449
445
437
436457
477
496
513
525530532532532
533536525508504
508502480
495513
531541538526524
501541
436
Oct.
524524537549
554
556556550538
_ ...
485
481
493512523531539
545549551556553
546540546
550549
550
537556
481
Nov.
546
543541543544
544549556
558558
558560562563565
566566
565560561
562
565566
568567
567
565565
566
565
559568
541
Dec.
560557558563566
554548552
555556
555557557557557
557557565571571
570571576575568
570576590604611
619
568619
548
Jan.
626
631
632...
630
634
634
628
616
608
607
609
613
619
623
618614...
624
627
628628
623617
612
609608606
620634
606
Meen Daily Specific Conductance of Water From Observation Well CRM-4 49
Table 15. Mean daily specific conductance of water from municipal well Seminole 10, February 1, 1993, through January 31, 1994[Specific conductance given in microsiemens per centimeter at 25 degrees Celsius; , no data]
Day
l2345
67
8
910
1112131415
1617181920
2122232425
26272829
3031
MeanMaximumMinimum
Feb.
538539539541542
542541......
575
587608627634
635
630615609610609
627600590595606
619 .........
590635
538
Mar.
...
...636635634
634635626596571
520445
383348325
310305306313326
349381417
453
469
463 .........
462636
305
Apr.
...
...
...
...
...
...
...'...
...287
288290299321
355
390423450470
487
495500506510508
499492486477
429...
427
510
287
May
386381388402416
430414404
395393
405405422448453
453451478505505
505507510514522
531538545547550550
463550
381
June
550550547
546544
541
533522541538
531515517517522
521516509500488
473454
449449
454
459460453443...
505550
443
July
418461460464
443447
467
473470
466
468468465
458
468478
476
480
458
438435441449455
456453446439
439443
456480
418
Aug.
447
453461470475
459440431
438442
447
436437434
427
429431431428427
425426426444
459
456451449444
441
438
442
475
425
Sept.
432428427429428
415417422425416
413419425433436
446459468477
485
495496491510517
515518525534538
461538
413
Oct.
537535534536541
548553556557555
549535526520512
501493492498506
515522530535539
542544546546544
540
532557
492
Nov.
537536535534533
532531530527525
528533534537542
546548550551551
551551562570570
572574575574
574
547
575
525
Dec.
574
573573572571
562556557558553
552550550548547
547
547
546
546
546
551
558566570571
571572572571570
571
560574
546
Jan.
575583593...
617
623628632
636638
640640637633628
625... .......
586585585585
587589591592592591
608640
575
50 Effect of the Cedar River on the Quality of the Ground-Water Supply for Cedar Repids, Iowa
Table 16. Mean daily specific conductance for water from observation well CRM-3, February 1, 1993, through January 31, 1994[Specific conductance given in microsiemens per centimeter at 25 degrees Celsius; , no data]
Day
12
34
5
678
910
1112131415
1617181920
2122232425
262728293031
MeanMax
imumMin
imum
Feb.
...
...
...
...
...
...
604
598588608624637
648655647622628
633627628629
609
603 .........
623655
588
Mar.
...
...610613...
...
605
605608
604597598600598
600604......
609
614601602606...
__
624611592572559
601624
559
Apr.
513513528566616
623626630...
614
622634643649650
640625629640641
638638621589
575
546524507486471...
593650
471
May
462460461458455
452451447444
451
453443435426455
470469475468480
512516515516510
503498490484
480478
472516
426
June
474
472
474
476
473
466462465465
459
458461462459
463
464456444443445
448451444439446
452456458458446...
458476
439
July
441445457473484
483471465477
494
506515508507508
...
523526530504
492524
535539535
505501502513542
563
502563
441
Aug.
579575565557548
533515515499492
492498509470472
490511520517517
530528515509501
505546597594600629
530629
470
Sept.
647674
687675665
640617633533...
476
485497
509
505
507511508496492
505514
516524519
514520536565588...
554687
476
Oct.
585587588587579
565558561
573583
591
592593593595
594585598620630
642651634618
596
577564554541
535529
587651
529
Nov.
523519515515518
514512
510511
512
512513514515515
515514516515515
516519521523524
524
526527530537
518
537
510
Dec.
548545540
550553
554556552
553552
579587582587586
575561...
568575
577561564579584
596631602590600596
573631
540
Jan.
592581580...
544
549553556
557559
559560560559559
558558557556556
564565567567
568569572575577581
564592
544
Mean Daily Specific Conductance for Water From Observation Well CRM-3 51
Table 17. Mean daily specific conductance of water from the Cedar Rapids municipal water-treatment plant, February 1, 1993, through January 31, 1994[Specific conductance given in microsiemens per centimeter at 25 degrees Celsius; , no data]
Day
12345
678
910
1112131415
1617181920
21
22232425
26272829
3031
MeanMaximumMinimum
Feb.
__
...
...
...
_ ...
_ ...
__
588588581585
586581567580
566
__
563581
...
579588
563
Mar.
590602594585584
585582
586586...
564576575565571
564544
578584573
576563569557
563549530518
513511
567602
511
Apr.
522512516530499
503
...
476
489498486489491
492496498508507
507509492494
490
483466465466474...
495530
465
May
471477473492486
471464468467
467
460475491487479
470473474477480
481483491499497
496502508513
510506
483513
460
June
505502494496500
505506
503500502
500500499495493
490492507500494
490491502497487
483475468474473...
494507
468
July
473464466462464
462
459 ...
...
_ ... ...
_...
...
............
_
...
464473
459
Aug.
... ......
_422
425
419424
430424424430420
421424425420418
423431431440453
453441443438436441
430453
418
Sept.
443445451439443
442447448448
449
465475471478492
479486489486485
486483481490492
486483484488485...
471492
439
Oct.
487488499488488
489
483482
481480
486478478478473
484476479477474
472479477471474
475476493513
509507
484513
471
Nov.
509504501503501
506496
506513525
520522518517517
518500498513513
513511517525
524
520522522519512
513525
496
Dec.
517516516517520
__
543544544
540
531528525522521
520518...
540538
536536534535
536
... ...
529544
516
Jan.
... ......
551
548543531528
525
527520527521523
528529525521526
514509514
511
523516519519
504519
524551
504
52 Effect of the Cedar River on the Quality of the Ground-Water Supply for Cedar Rapids, Iowa
Table 18. Mean daily pH of water from the Cedar River, surface-water monitoring site, February 1,1993, through January 31, 1994[pH given in standard units; , no data]
Day
12345
6789
10
1112131415
1617181920
2122232425
262728293031
MeanMaximumMinimum
Feb.
7.97.98.07.97.8
7.87.97.97.97.9
7.87.87.97.9
_
_
_
7.87.8
7.98.0
7.8
Mar.
7.8
7.8
7.8
7.6
7.5
7.5
7.4
7.5
7.5
7.6
7.6
7.6
7.7
7.7
7.8
7.8
7.9
7.7
7.6
7.6
7.7
7.7
7.7
7.7
7.6
7.5
7.4
7.4
7.3
7.3
7.4
7.6
7.9
7.3
Apr.
7.47.47.57.57.5
7.67.77.7
7.9
7.97.97.98.08.0
8.08.08.08.08.0
8.08.08.08.08.0
8.08.18.28.28.2
7.98.2
7.4
May
8.18.18.08.08.0
8.07.97.98.08.0
8.18.18.18.18.1
8.28.2
_
8.38.38.38.3
8.48.58.48.38.48.4
8.28.5
7.9
June
8.58.58.38.28.2
8.28.28.18.07.9
7.97.98.08.08.1
8.07.97.87.87.7
7.87.77.77.87.8
7.97.97.98.07.9
8.08.5
7.7
July
7.98.08.08.08.0
8.08.08.18.07.9
7.87.87.98.08.0
7.97.87.87.87.9
7.97.98.08.08.0
8.18.18.18.18.18.1
8.08.1
7.8
Aug.
8.08.18.18.28.2
8.07.87.98.07.8
7.87.97.97.97.8
7.87.87.97.87.8
7.87.97.98.08.1
8.18.18.18.18.18.2
8.08.2
7.8
Sept.
8.28.28.38.38.3
8.38.48.48.48.3
8.38.38.38.28.2
8.28.38.38.28.2
8.28.28.38.28.0
8.08.08.18.28,2
8.28.4
8.0
Oct.
8.28.38.48.48.3
8.28.28.18.28.2
8.28.38.38.28.1
8.28.28.28.28.2
8.38.48.38.28.2
8.28.28.38.38.48.4
8.38.4
8.1
Nov.
8.48.48.48.48.4
8.48.48.48.38.1
8.28.18.18.18.1
8.18.18.28.28.2
8.28.28.38.38.3
8.38.38.38.38.3
8.38.4
8.1
Dec.
8.28.28.28.28.2
8.28.28.28.28.1
8.28.18.18.18.1
8.18.1
8.17.9
7.87.77.77.77.8
7.87.87.87.87.87.8
8.08.2
7.7
Jan.
7.8
7.8
7.8
7.8
7.8
7.7
7.7
7.7
7.7
7.7
7.7
7.77.7
7.7
7.7
7.7
7.7
7.7
7.7
7.7
7.7
7.7
7.7
7.7
7.7
7.7
7.77.7
7.7
7.7
7.7
7.7
7.8
7.7
Mean Daily pH of Water From Cedar River 53
Table 19. Mean daily pH of water from observation well CRM-4, February 1, 1993, through January 31, 1994[pH given in standard units; , no data]
Day
12345
6789
10
1112131415
1617181920
2122232425
262728293031
MeanMaximumMinimum
Feb.
7.8
7.8
7.87.9
7.9
7.9
7.9
7.9
7.9
7.7
7.7
7.8
7.8
7.8
7.8
7.8
7.8
7.87.7
7.8
7.7
7.7
7.7
7.7
7.7
7.7
7.7
...
7.8
7.9
7.7
Mar.
_ 7.87.87.8
7.98.08.08.18.1
8.18.08.08.08.0
8.08.07.97.87.8
7.87.87.87.97.8
7.77.77.87.87.87.8
7.98.1
7.5
Apr.
7.87.87.87.87.8
7.87.87.8
7.8
7.87.77.77.77.7
7.6
_...
7.57.6
7.67.67.67.67.6
7.77.8
7.6
May
7.6
7.6
7.6
7.6
7.6
7.7
7.7
7.7
7.7
7.7
7.7
7.8
7.8
7.8
7.8
7.87.8
7.7
7.6
7.6
7.6
7.6
7.6
7.7
7.7
7.7
7.7
7.7
7.7
7.7
7.8
7.7
7.8
7.5
June
7.87.87.67.57.6
7.67.67.67.67.6
7.67.67.67.67.6
7.67.67.67.67.6
7.57.57.57.67.6
7.67.67.67.67.6
7.67.8
7.4
July
7.57.47.47.47.4
7.47.47.47.47.4
7.47.47.57.57.5
7.57.57.57.57.6
7.67.67.67.77.7
7.67.67.67.67.67.6
7.57.7
7.5
Aug.
7.6
7.6
7.7
7.7
7.7
7.6
7.5
7.5
7.6
7.6
7.6
7.6
7.6
7.7
7.7
7.7
7.7
7.77.7
7.7
7.7
7.8
7.8
7.7
7.7
7.7
7.7
7.7
7.7
7.7
7.7
7.7
7.8
7.4
Sept.
7.7
7.7
7.77.7
7.7
7.8
7.8
7.7
7.7
7.5
7.4
7.4
7.4
7.4
7.5
7.5
7.5
7.57.5
7.5
7.5
7.6
7.6
7.6
7.6
7.7
7.7
7.7
7.7
7.7
7.6
7.8
7.6
Oct.
7.77.77.87.87.8
7.87.87.87.9
_ ...
7.67.6
7.67.77.87.87.8
7.87.87.87.87.8
...............
7.87.9
7.6
Nov.
_
_... 7.6
7.6
7.6
7.7
7.7
7.7
7.7
7.7
7.7
7.77.7
7.7
7.7
7.8
7.9
7.9
7.9
8.0
8.0
8.0
8.0
7.8
8.0
7.8
Dec.
8.08.08.08.18.1
8.07.87.97.97.9
7.98.08.08.08.0
8.08.08.18.28.2
8.28.28.28.28.2
8.28.28.28.28.28.2
8.18.2
7.7
Jan.
8.28.28.2
8.1
8.18.18.18.18.1
8.18.18.18.18.1
8.18.1
...
_
7.87.87.77.7
7.77.77.77.77.77.7
8.08.2
7.7
54 Effect of the Cedar River on the Quality of the Ground-Water Supply for Ceder Rapids, lowe
Table 20. Mean daily pH of water from municipal well Seminole 10, February 1, 1993, through January 31, 1994[pH, given in standard units; . no data]
Day
12345
678
910
11121314.
15
1617181920
2122232425
262728293031
MeanMaximumMinimum
Feb.
7.47.47.47.47.4
7.47.4
7.2
7.37.57.57.57.5
7.67.57.47.57.6
7.67.77.77.77.7
7.7
7.57.7
7.2
Mar.
...
7.47.47.4
7.47.57.57.57.5
7.57.57.67.67.6
7.77.77.77.77.6
7.67.67.67.67.6
7.6 ......
7.67.7
7.4
Apr.
...
_
7.7
7.87.87.87.87.8
7.77.77.77.77.8
7.97.77.67.67.6
7.67.67.67.67.6
7.77.9
7.6
May
7.67.67.67.67.6
7.67.77.77.77.7
7.77.87.87.87.7
7.77.77.77.67.6
7.67.67.77.77.8
7.87.87.87.87.87.8
7.77.8
7.6
June
7.87.87.67.57.5
7.57.57.57.67.6
7.67.57.5
7.57.5
7.67.67.57.57.5
7.67.67.67.57.6
7.67.57.67.6 ...
7.67.8
7.5
July
...7.67.67.77.7
7.77.77.77.77.7
7.77.87.87.87.8
7.67.57.57.67.5
7.57.57.57.57.5
7.67.67.67-7.7.77.7
7,67.8
7.5
Aug.
7.77.77.77.77.7
7.67.67.77.77.7
7.77.77.77.77.8
7.87.87.87.87.8
7.97.97.97.77.7
7.77.77.87.87.87.8
7.77.9
7.6
Sept.
7.87.87.87.87.9
7.97.97.97.97.8
7.77.77.77.77.7
7.77.87.87.87.8
7.87.87.87.67.6
7.67.67.67.67.6
7.77.9
7.6
Oct.
7.67.67.67.67.6
7.67.77.77.77.7
7.77.67.77.77.8
7.87.97.97.97.9
8.08.08.08.08.0
8.08.0
7.88.0
7.6
Nov.
...
... ... 7.4
7.47.57.57.57.5
7.57.67.67.67.6
7.67.67.67.67.7
7.77.77.77.77.7
...
7.67.7
7.4
Dec.
7.77.77.77.77.7
7.77.77.77.77.5
7.57.57.67.67.6
7.67.77.67.67.6
7.67.77.77.77.8
7.87.87.87.87.87.8
7.77.8
7.5
Jan.
7.87.87.8
7.6
7.67.77.77.77.7
7.77.77.77.77.7
7.7 ......
7.67.67.67.6
7.77.77.77.77.77.7
7.77.8
7.6
Mean Daily pH of Water From Municipal Well Seminole 10 55
Table 21 . Mean daily pH of water from observation well CRM-3, February 1, 1993, through January 31,1994[pH, given in standard units; , no data]
Day
12345
6789
10
1112131415
1617181920
2122232425
262728293031
MeanMaximumMinimum
Feb.
...
...
...
...
_ ...
7.3
7.37.37.37.37.2
7.27.37.27.27.2
7.27.27.27.27.2
7.2............
7.27.3
7.2
Mar.
...
...7.27.2
...
_
7.27.27.2
7.37.37.37.37.3
7.37.3
...
7.2
7.27.27.27.2
_
7.37.37.37.37.3
7.37.3
7.2
Apr.
7.47.47.47.47.4
7.47.47.4
...
7.2
7.27.27.27.27.2
7.27.27.27.27.2
7.27.27.27.27.2
7.17.27.27.27.2
7.37.4
7.1
May
7.37.37.37.37.3
7.37.37.37.37.3
7.47.47.47.47.4
7.47.47.37.37.3
7.37.37.37.37.3
7.37.37.37.37.37.3
7.37.4
7.3
June
7.47.47.37.27.2
7.27.27.27.27.2
7.27.27.37.37.3
7.27.27.37.37.3
7.37.37.37.37.3
7.37.37.37.37.3
...
7.37.4
7.2
July
7.37.27.27.27.2
7.27.27.27.27.1
7.17.17.27.27.2
7.27.27.27.2
7.3
7.37.37.37.37.3
7.37.37.37.37.37.3
7.27.3
7.1
Aug.
7.37.37.37.37.3
7.27.17.17.17.2
7.27.27.27.27.2
7.27.27.27.27.2
7.27.27.27.27.1
7.17.17.17.17.17.1
7.27.3
7.1
Sept.
7.17.07.07.07.0
7.07.07.07.1
7.07.17.17.17.1
7.17.17.17.17.1
7.17.17.27.17.0
7.17.17.17.17.1
7.17.2
7.0
Oct.
7.17.17.17.17.1
7.17.17.17.17.1
7.17.17.07.07.0
7.07.17.17.17.1
7.17.17.17.16.9
_.........
7.17.1
6.9
Nov.
... ......
_ 7.0
7.07.17.17.17.1
7.17.17.17.17.1
7.17.17.27.27.2
7.27.27.37.37.3
...
7.17.3
7.0
Dec.
7.37.37.37.37.3
7.27.27.27.27.2
7.27.27.27.27.2
7.27.2
...
7.27.2
7.37.37.37.37.3
7.37.37.37.37.47.4
7.37.4
7.2
Jan.
7.47.47.4
...
7.4
7.47.47.47.47.4
7.47.47.47.47.4
7.47.47.47.47.5
7.17.17.17.1
7.17.17.27.27.27.2
7.37.5
7.1
56 Effect of the Cedar River on the Quality of the Ground-Weter Supply for Cedar Rapids, iowa
Table 22. Mean daily pH of water from the Cedar Rapids municipal water-treatment plant, February 1, 1993, through January 31, 1994[pH given in standard units; , no data]
Day12345
6789
10
1112131415 .
1617181920
2122232425
262728293031
MeanMaximumMin
imum
Feb. ...
_... ......
... ......
. 7.27.27.27.2
7.27.27.27.27.3
7.37.37.3 ...
7.27.3
7.2
Mar.7.37.37.37.37.3
7.37.37.37.3
...
7.37.37.37.37.3
7.37.37.37.37.3
7.37.37.37.3
...
7.37.37.37.37.37.3
7.37.3
7.3
Apr.7.37.37.37.37.3
7.4...
7.3
7.47.37.37.37.3
7.47.47.47.47.4
7.47.47.47.47.4
7.47.37.27.27.2
7.37.4
7.2
May7.27.27.27.27.2
7.27.27.37.37.3
7.27.27.27.27.2
7.27.27.27.27.2
7.37.57.57.57.5
7.57.57.57.57.57.5
7.37.5
7.2
June July7.5 7.47.5 7.47.4 7.47.3 7.47.3 7.4
7.3 7.47.3 7.47.37.37.3
7.37.37.37.37.3
7.37.37.37.37.3
.7.37.37.37.37.3
7.37.37.47.37.4
7.3 7.47.5 7.4
7.3 7.4
Aug.......
_7.27.27.27.2
7.27.27.27.27.2
7.27.27.27.27.2
7.27.27.27.06.7
6.7...... ...
7.17.2
6.7
Sept.... ...
_... ...
7.27.27.27.27.2
7.37.37.37.37.3
7.37.37.27.17.1
7.17.06.96.96.9
...
7.27.3
6.9
Oct.6.96.96.97.07.0
7.07.07.07.07.0
7.07.07.17.37.3
7.37.37.37.37.3
7.37.37.37.37.3
7.37.37.37.37.37.3
7.27.3
6.9
Nov.7.37.37.3
. 7.37.3
7.37.37.47.37.2
7.37.37.37.37.3
7.37.37.37.37.3
7.37.37.27.27.2
7.27.27.27.37.3
...
7.37.4
7.2
Dec.7.37.37.37.37.3
__
7.37.37.37.3
7.37.37.37.37.3
7.37.3
7.27.3
7.37.37.37.47.3
............
7.37.4
7.2
Jan. ... ...
6.3
6.36.36.36.36.3
6.36.36.36.36.3
6.46.46.46.46.4
6.46.46.46.4
6.46.46.46.46.46.4
6.46.4
6.3
Mean Daily pH of Water From Water-Treatment Plant 57
Table 23. Mean daily temperature of water from the Cedar River, surface-water monitoring site, February 1, 1993, through January 31, 1994[Temperatures given in degrees Celsius;. , no date]
Day
12345
6789
10
1112131415
161718
1920
2122232425
262728293031
MeanMaximumMinimum
Feb. Mar.
-0.1 -0.1-.1 -.1-.1 -.1-.1 -.1-.1 -.1
-.1 -.1-.1 0-.1 .1-.1 .1-.1 0
-.1 0-.1 0-.1 .1-.1 .2
.4
.5
.2jj
.2
j.13
1.62.5
3.4-.1 3.3-.1 3.5
3.63.74.2
-.1 .9-.1 4.2
-.1 -.1
Apr.
3.73.43.63.74.2
5.26.47.3
8.1
8.47.97.77.16.0
4.85.97.48.58.1
8.89.39.6
10.310.8
11.812.212.313.514.1
7.914.1
3.4
May
14.213.913.713.013.1
13.514.416.417.918.4
18.719.118.318.018.0
17.416.6
_
13.914.014.114.1
15.316.917.416.316.015.7
15.919.1
13.0
June
15.314.113.513.713.8
15.115.716.717.918.8
19.820.420.621.120.7
19.719.420.320.520.1
20.020.721.321.521.5
21.622.022.021.720.5
19.022.0
13.5
July
19.820.621.922.521.5
21.121.121.020.921.2
21.521.921.721.421.3
21.321.421.621.922.3
22.121.620.921.021.8
22.723.223.222.622.722.5
21.723.2
19.8
Aug.
21.621.621.521.120.3
19.719.920.420.921.4
22.423.023.523.622.7
22.623.023.322.922.9
22.822.422.623.123.6
24.224.623.822.121.420.7
22.224.6
19.7
Sept.
20.219.919.619.519.0
18.118.118.218.017.3
16.717.518.917.715.6
14.714.614.914.614.7
15.316.016.115.614.9
13.712.912.912.512.1
16.320.2
12.1
Oct.
12.612.512.413.213.0
13.815.616.815.012.6
11.411.210.911.312.1
12.712.812.212.412.4
11.110.210.511.111.6
11.39.89.07.35.74.6
11.616.8
4.6
Nov.
4.14.35.06.66.6
4.43.03.43.94.4
5.25.06.16.05.5
4.75.04.54.63.8
3.94.34.84.94.3
2.31.0
.6
.1-.1
4.16.6
-.1
Dec.
0.1.8
1.32.02.4
2.41.61.62.22.2
.6
.21.21.72.3
2.83.2
3.32.7
1.5.4
-.1-.1-.1
-.1-.1-.1-.1-.1-.1
1.23.3
-.1
Jan.
-0.1-.1-.1-.1-.1
-.1-.1-.1-.1-.1
-.1-.1-.1-.1-.1
-.1-.1-.1-.1-.1
-.1-.1-.1-.1-.1
000000
-.10
-.1
58 Effect of the Cedar River on the Quality of the Ground-Water Supply for Cedar Rapids, Iowa
Table 24. Mean daily temperature of water from observation well CRM-4, February 1,1993, through January 31,1994[Temperatures given in degrees Celsius; , no data]
Day
12
3
4
5
6
78
9
10
11
12
1314
15
16
17
18
19
20
21
22
2324
25
26
27
28
29
30
31
MeanMaximumMinimum
Feb.
0.9
.9
.9
.9
.9
.9
.9
.9
.9
.8
.7
.4
.2
.1
.1
.1
.1
.1
.1
.1
.1
.1
.1
.1
.1
.1
.1
...
...
.4
.9
.1
Mar.
...
...0.1
.1
.1
.1
.1
.1
.1
.1
.1
.1
.1
.1
.2
.2
2
.3
.2
.2
.3
.4
.5
.5
.4
.3
.3
.3
.4
.6
1.1
.3
1.1
.1
Apr.
1.8
2.6
3.1
3.3
3.5
3.6
3.7
3.9
4.0
3.9
4.1
4.7
5.9
7.2
8.0
...
...
_
8.2
8.4
8.7
9.2
9.6
10.1
10.6...
5.8
10.6
1.8
May
11.5
12.1
12.5
13.6
14.2
14.3
14.1
14.1
14.1
14.1
14.1
14.0
14.0
13.7
13.3
13.3
14.1
16.5
18.0
18.1
17.8
17.1
16.3
15.5
14.7
14.1
14.1
14.1
14.2
14.3
15.0
14.5
18.1
11.5
June
16.3
17.116.8
16.4
16.0
15.6
14.9
14.4
14.0
13.9
14.3
15.2
15.4
15.6
15.7
15.9
16.8
17.8
18.6
19.4
19.7
19.6
20.0
20.4
20.5
20.4
20.3
20.5
21.0
21.5...
17.5
21.5
13.9
July
... .........
...
_ ...
22.0
21.9
21.9
21.9
21.6
21.0
20.7
20.6
21.1
21.9
22.1
21.5
21.4
22.6
23.5
21.7
23.5
20.6
Aug.
23.3
22.9
22.8
22.9
22.0
21.8
21.8
21.7
21.7
21.6
21.3
20.8
20.6
20.2
20.0
20.2
20.8
21.6
22.6
23.3
23.5
23.2
23.1
23.4
23.2
23.1
23.0
22.9
22.7
22.9
23.4
22.2
23.5
20.0
Sept.
23.9
24.4
24.5
23.8
22.6
21.7
21.0
20.5
20.1
19.8
19.6
19.1
18.6
18.3
18.3
18.217.8
17.3
17.5
18.4
18.3
16.7
15.3
15.0
14.9
15.1
15.7
16.1
16.1
15.8...
18.8
24.5
14.9
Oct.
15.3
14.6
13.8
13.3
13.0
12.8
12.6
12.6
12.6...
_
15.6
15.9
15.013.4
12.2
11.6
11.4
11.6
12.1
12.6
12.7
12.6
12.4
11.9
11.2
10.8
10.9
11.3
12.8
15.9
10.8
Nov.
11.4
11.1
.10.3
9.4
8.2
6.8
5.6
4.8
4.8
5.3
5.9
6.1
5.5
4.3
3.8
4.1
4.6
5.1
5.6
6.0
6.0
5.7
5.3
5.0
4.8
4.5
4.2
4.3
4.6
4.9...
5.9
11.4
3.8
Dec. Jan.
4.7 0.1
3.8 .1
2.5 .1
1.5
.8 .1
.4 .1
.2 .1
.3 .1
.8 .1
1.5 .1
1.7 .1
1.8 .1
1.8 .1
1.9 .1
1.9 .1
1.9 .11.8 .1
1.9
1.8
1.8
2. 1
2.3 .1
2.0 .1
1.9 .1
1.9 .1
2.2 .1
2.4 .1
1.5 .1
.6 .1
.2 .1
.1 .1
1.7 .1
4.7 .1
.1 .1
Mean Daily Temperature of Water From Observation Well CRM-4 59
Table 25. Mean daily temperature of water from municipal well Seminole 10, February 1,1993, through January 31, 1994[Temperatures given in degrees Celsius; , no data]
Day
12345
6789
10
1112131415
1617181920
2122232425
262728293031
MeanMaximumMinimum
Feb.
6.56.56.56.56.5
6.46.4
...
...
6.1
5.11.71.0.8.6
.42.94.44.44.5
.7
.200-.1
-.1
3.26.5
-.1
Mar.
__
...-0.1
-.1-.2
-.2-.2-.2-.2-.2
-.2-.2-.2-.2-.2
-.2-.1-.1-.1-.1
__-.-.-.-.
-.1
-.2-.1
-.2
Apr.
__
...
...
...
_._ ...
2.2
2.52.83.03.13.3
3.43.74.14.65.4
6.16.26.36.76.9
6.76.56.66.87.0
4.97.0
2.2
May
7.27.58.08.59.0
9.57.36.86.76.8
7.37.38.3
10.210.8
11.311.812.012.112.3
12.512.913.213.513.8
14.114.514.815.115.215.1
10.815.2
6.7
June
15.014.814.714.714.7
14.713.712.415.115.3
15.413.112.512.812.7
13.815.115.015.014.9
14.915.215.515.715.7
15.916.216.516.9...
14.816.9
12.4
July
...17.114.514.514.4
15.715.514.613.613.6
13.614.414.614.213.7
13.713.713.414.115.2
17.018.218.618.919.0
19.119.620.020.320.520.7
16.220.7
13.4
Aug.
20.820.921.021.021.1
21.019.218.519.219.2
19.619.618.819.918.5
19.520.320.120.420.2
20.319.919.719.218.5
18.618.718.518.518.418.2
19.621.1
18.2
Sept.
18.418.518.518.318.5
20.320.319.920.220.8
21.121.221.420.621.2
21.121.221.020.820.6
19.819.118.718.117.4
17.016.616.316.015.9
19.321.4
15.9
Oct.
15.815.715.515.315.0
14.614.313.913.613.4
13.213.013.013.013.2
13.513.813.913.813.6
13.312.912.612.412.4
12.412.412.312.212.111.9
13.515.8
11.9
Nov.
11.811.711.611.511.4
11.210.910.510.19.5
8.98.27.87.26.7
6.35.95.75.45.2
5.05.05.05.05.0
5.05.05.05.05.0
7.611.8
5.0
Dec.
5.04.94.94.84.7
4.54.34.54.46.8
6.46.46.56.56.5
6.66.66.66.66.6
6.13.82.72.01.7
1.6.6.6.6.7.8
4.56.8
1.6
Jan.
1.81.81.7
1.3
1.1.9.7.5.4
.3
.2
.1
.10
0...... ...
-.1-.2-.2-.1
-.2-.2-.2-.2-.1-.1
.41.8
-.2
60 Effect of the Cedar River on the Quality of the Ground-Water Supply for Cedar Rapids, Iowa
Table 26. Mean daily temperature of water from observation well CRM-3, February 1, 1993, through January 31,1994[Temperatures given in degrees Celsius; , no data]
Day
12
3
4
5
6
7
8
9
10
1112
13
14
15
16
17
18
19
20
21
22
2324
25
26
27
28
29
30
31
MeanMax
imumMin
imum
Feb.
... ...
...... 0.6
.6
.6
.6
.7
.7
.8
.9...
1.01.1
1.31.51.6
1.8
2.0
2.3
...
...
1.1
2.3
.6
Mar.
...
3.4
3.6
...
3.1
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.1
3.3
3.3
3.3
3.3
3.2
3.2
3.1
3.0
3.1
3.6
3.0
Apr.
3.03.0
2.9
2.9
2.9
2.9
3.0
3.2
3.6
3.7
3.8
3.9
4.0
4.1
4.2
4.2
4.3
4.3
4.3
4.4
4.4
4.4
4.4
4.5
4.5
4.6
4.7
4.8
4.9
3.9
4.9
2.9
May
5.0
5.0
5.1
5.1
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
4.9
4.9
4.9
4.9
4.9
4.9
4.9
4.9
4.9
4.9
5.0
5.0
5.1
5.2
5.2
5.2
5.3
5.3
5.3
5.0
5.3
4.9
June
5.4
5.4
5.3
5.2
5.2
5.1
5.1
5.0
5.0
4.9
5.0
5.0
5.0
5.1
5.1
5.0
5.0
5.0
5.0
5.1
5.1
5.1
5.2
5.2
5.3
5.3
5.5
5.6
5.7
5.2
5.7
4.9
July
5.96.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.1
6.1
6.1
6.1
__
6.1
6.1
6.1
6.2
6.4
6.5
6.6
6.7
6.9
7.1
7.3
7.5
7.8
8.1
8.3
6.5
8.3
5.9
Aug.
8.5
8.6
8.8
8.9
9.1
9.3
9.3
9.5
9.9
10.3
10.4
10.2
10.3
10.6
10.7
11.3
11.7
11.5
11.4
11.4
11.5
11.6
11.7
11.8
11.8
11.7
11.6
11.7
11.6
11.6
11.7
10.6
11.8
8.5
Sept.
11.812.0
12.2
12.3
12.5
12.7
12.9
13.2
13.4
13.9
14.0
14.2
14.3
14.6
14.7
14.9
15.0
15.2
15.4
15.4
15.4
15.3
15.4
15.3
15.3
15.3
15.2
15.1
15.1...
14.2
15.4
11.8
Oct.
15.1
15.2
15.3
15.4
15.5
15.7
15.8
15.9
16.0
16.2
16.3
16.2
16.1
16.1
16.1
16.1
16.2
16.2
16.2
16.3
16.3
16.3
16.3
16.3
16.3
16.3
16.3
16.3
16.4
16.4
16.4
16.0
16.4
15.1
Nov.
16.5
16.5
.16.6
16.6
16.6
16.7
16.8
16.8
17.0
17.1
17.1
17.2
17.3
17.3
17.4
17.5
17.5
17.7
17.8
18.0
18.1
18.1
18.2
18.2
18.3
18.3
18.4
18.4
18.4
18.5
17.5
18.5
16.5
Dec.
18.6
18.7
18.6
18.5
18.4
__
18.3
18.2
18.0
17.7
17.2
16.8
16.6
16.5
16.5
16.3
15.8...
13.9
12.6
11.6
12.6
14.2
15.1
15.7
15.9
16.0
16.0
15.9
15.8
15.7
16.3
18.7
11.6
Jan.
15.7
15.6
15.4
15.1
15.0
14.8
14.7
14.6
14.4
14.3
14.2
14.1
14.0
13.9
13.8
13.7
13.6
13.5
13.5
13.2
13.1
13.1
13.0
12.9
12.8
12.7
12.6
12.5
12.4
13.9
15.7
12.4
Mean Daily Temperature of Water From Observation Well CRM-3 61
Table 27. Mean daily temperature of water from the Cedar Rapids municipal water-treatment plant, February 1, 1993, through January 31, 1994[Temperatures given in degrees Celsius; , no data]
Day
12345
67
8
910
1112131415
1617181920
2122232425
262728293031
MeanMaximumMin-mum
Feb.
__
...
...
...
... ...
_ .........
_11.011.411.110.9
10.510.410.810.610.6
10.510.510.6 ......
10.711.4
10.4
Mar.
10.710.810.710.510.5
10.510.510.510.3...
9.39.49.79.59.4
8.88.89.49.09.0
9.09.69.59.3
...
9.59.48.98.58.08.1
9.610.8
8.0
Apr.
8.06.86.6
6.8
6.4
6.7
7.2
...
5.9
6.0
6.3
6.6
6.7
6.8
6.87.1
7.1
7.0
7.2
7.3
7.5
7.47.5
7.6
7.5
7.7
7.9
8.1
7.7...
7.1
8.1
5.9
May
7.87.97.98.08.1
8.38.78.28.58.8
9.69.79.79.99.8
10.310.711.211.311.5
11.010.810.910.710.8
11.111.211.010.811.011.1
9.911.5
7.8
June
11.4
11.2
11.8
12.0
11.3
10.8
11.5
12.2
12.1
11.5
11.5
11.7
11.8
12.2
12.1
12.7
12.2
11.1
11.2
11.7
11.8
12.0
11.3
11.9
12.2
12.2
12.6
12.9
12.7
12.7...
11.9
12.9
10.8
July
12.913.513.013.313.3
14.014.0 ...
_ .........
_
15.014.715.115.6
15.314.715.115.716.3
15.616.316.616.515.816.2
14.916.6
12.9
Aug.
16.816.917.016.917.1
17.316.716.617.316.7
16.416.917.016.317.3
17.316.716.717.217.0
16.416.416.616.616.3
16.617.516.716.817.016.9
16.817.5
16.3
Sept.
16.716.816.517.517.3
16.817.316.816.817.1
17.217.217.616.316.2
17.016.216.016.016.6
16.816.916.816.917.1
17.016.916.816.516.6...
16.817.6
16.0
Oct.
16.416.315.915.915.8
15.616.215.915.815.8
15.315.715.615.615.7
15.515.515.314.814.6
14.614.514.514.814.8
14.714.614.514.414.314.2
15.316.4
14.2
Nov.
14.2
14.2
14.1
14.1
14.1
14.0
13.8
13.8
13.7
13.5
13.4
13.1
13.2
13.2
13.0
12.613.013.112.812.7
12.512.512.412.412.4
12.612.912.812.111.8
13.114.2
11.8
Dec.
11.511.311.311.211.0
11.010.910.810.6
10.710.710.410.710.7
10.610.3
10.210.1
10.110.110.110.310.2
...............
10.611.5
10.1
Jan.
__
...
...
...9.7
9.59.49.38.98.4
8.58.98.68.58.7
8.48.28.48.78.4
8.48.58.88.4
7.97.88.18.08.78.4
8.69.7
7.8
62 Effect of the Cedar River on the Quality of the Ground-Weter Supply for Cedar Rapids, Iowa
Table 28. Mean daily concentration of dissolved oxygen in water from the Cedar River, surface-water monitoring . site, February 1, 1993, through January 31,1994
[Dissolved-oxygen concentration given in milligrams per liter; , no data]
Day
12
345
6789
10
11121314
15
1617181920
2122232425
262728293031
MeanMaximumMinimum
Feb.
12.012.212.112.212.3
12.112.212.212.312.3
11.911.211.211.8
...
_ ..-
__
14.514.5
12.314.5
11.2
Mar.
14.614.715.215.114.4
13.712.912.311.912.1
12.212.813.413.713.9
14.214.614.714.714.6
14.715.015.114.614.0
12.912.611.710.99.99.2
13.415.2
9.2
Apr.
10.411.311.912.412.2
11.811.310.8
10.7
10.510.710.911.011.5
12.212.211.611.010.9
11.010.810.39.89.5
9.49.69.89.89.9
10.912.4
9.4
May
9.79.59.29.59.8
9.79.18.68.58.4
8.58.48.38.28.2
8.48.4
_
9.39.09.09.5
9.89.68.68.18.69.0
8.99.8
8.1
June
9.38.88.78.48.4
8.38.07.46.96.7
6.56.46.46.36.4
7.17.67.47.26.9
7.27.16.86.56.7
6.96.96.97.17.0
7.39.3
6.3
July
7.06.96.76.66.7
6.76.86.96.76.3
6.26.26.46.56.5
6.97.16.86.86.9
6.96.97.17.27.1
7.06.86.66.46.56.4
6.77.2
6.2
Aug.
6.26.66.76.87.1
7.67.87.77.76.9
6.87.06.96.76.4
6.46.36.46.16.0
6.26.46.46.97.3
7.17.07.07.27.27.4
6.87.8
6.0
Sept.
7.77.88.08.08.0
8.28.68.88.99.1
9.19.18.58.18.5
9.19.59.18.98.9
8.98.88.89.69.9
9.910.210.5II. 111.1
9.011.1
7.7
Oct.
11.111.311.511.511.5
11.611.310.811.110.5
11.011.512.312.311.5
10.910.610.810.910.5
11.312.112.212.212.1
11.411.812.913.413.914.6
11.714.6
10.5
Nov.
14.814.414.113.512.6
13.414.314.113.512.7
12.411.711.111.111.4
11.711.912.011.912.1
12.212.012.512.412.3
13.113.613.914.114.0
12.814.8
11.1
Dec.
14.013.713.513.012.7
13.514.514.514.113.8
14.614.914.313.813.7
13.413.1
12.913.1
13.814.414.714.914.6
14.213.813.814.014.414.2
13.914.9
12.7
Jan.
13.913.713.313.113.1
13.012.912.912.712.5
12.312.111.911.811.8
11.711.611.511.311.2
11.010.710.710.710.7
10.911.011.011.111.211.3
11.913.9
10.7
Mean Daily Dlssolved-Oxygen Concentration in Water From Cedar River 63
Table 29. Mean daily concentrations of dissolved oxygen in water from observation well CRM-4, February 1, 1993, through January 31,1994[Dissolved-oxygen concentration given in milligrams per liter; , no data]
Day
12345
6789
10
1112131415
1617181920
2122232425
262728293031
MeanMaximumMinimum
Feb.
5.25.45.86.46.0
5.75.76.06.15.8
7.46.86.4
6.07.58.89.08.4
9.59.06.87.69.6
9.49.3
... ......
7.29.6
5.2
Mar.
...
9.77.98.9
8.26.64.01.1
.8
.7
.6
.6
.6
.5
.5
.6
2.22.6
4.24.53.83.43.7
3.83.12.01.0.9.9
3.19.7
.5
Apr.
0.8.8.8.8.8
.8
.7
.7
.8
.81.33.63.84.8
5.5
...
7.16.6
6.15.24.54.25.2
3.07.1
.7
May
5.25.04.84.33.9
3.83.53.33.33.1
2.72.63.02.31.2
2.22.82.73.13.0
3.13.44.04.34.5
4.54.55.14.73.72.7
3.65.2
1.2
June
2.42.72.51.91.5
2.12.42.62.41.7
1.61.5.8.7.7
1.2.6.4
1.72.0
1.5.5.4.4.3
.3
.3
.4
.4
.7...
1.32.7
.3
July
0.9.8
_
_
.3
.3
.3
.3
.3
.3
.3
.3
.6
1.21.21.42.62.42.3
.92.6
.3
Aug.
1.92.12.01.42.0
2.22.21.31.11.3
.92.01.9
.5
.2
.2
.3
.2
.5
.2
.2
.2
.2
.2
.2
.2
.2
.2
.2
.2
.2
.92.2
.2
Sept.
0.2.1.2.3.4
1.01.31.61.7
1.51.82.02.53.2
3.22.72.33.13.8
4.13.83.7
4.1
4.44.64.44.24.1
...
2.54.6
.1
Oct.
4.34.44.75.15.1
5.25.24.84.9
...
1.71.6
1.92.32.01.2
.6
.7
.91.11.43.5
4.84.54.94.43.44.6
3.35.2
.6
Nov.
5.46.06.87.78.5
8.78.47.06.67.3
7.77.67.57.16.7
6.05.76.06.56.5
6.36.36.97.67.7
7.67.77.88.29.2
7.29.2
5.4
Dec.
9.910.110.611.011.0
11.411.310.910.611.0
11.010.910.810.710.6
10.610.611.011.1
11.78.54.87.7
11.4
11.912.212.312.011.711.2
10.712.3
4.8
Jan.
11.011.211.7
11.5
10.910.29.8
10.010.2
9.99.79.49.18.6
8.38.4 ...
6.76.56.46.0
5.75.55.35.04.74.4
8.311.7
4.4
64 Effect of the Cedar River on the Quality of the Ground-Water Supply for Cedar Rapids, Iowa
Table 30. Mean daily concentration of dissolved oxygen in water from municipal well Seminole 10, February 1, 1993, through January 31, 1994[Dissolved-oxygen concentration given in milligrams per liter; , no data]
Day
12
3
4
5
6
7
8
910
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
MeanMax
imumMinimum
Feb.
0.4
.4
.4
.6
.5
.5
.4
2.5
5.2
6.4
7.2
7.5
7.6
4.6
4.2
2.6
1.9
7.1
6.3
6.0
6.9
7.8
7.8
4.1
7.8
.4
Mar.
...
...
9.69.2
9.2
9.1
8.8
8.4
8.2
8.0
7.2
5.8
4.0
2.5
1.8
1.4
1.2
1.4
1.3
1.2
1.5
2.1
3.0
3.9
4.5
5.0
...
4.9
9.6
1.2
Apr.
...
...
...
...
_
1.0
1.0
.9
.9
.9
.9
.9
.9
.8
.8
.8
.9
1.2
1.4
1.7
1.9
2.0
2.1
2.3
2.2
2.0...
1.3
2.3
.8
May
1.6
1.3
1.3
1.2
1.2
.9
1.1
1.0
.9
.9
.9
.9
.9
.7
.7
.7
.6
.7
.7
.7
.7
.7
.7
.7
.7
.7
.7
.7
.7
.7
.8
.9
1.6
.6
June
0.8
.7
.7
.7
.6
.6
.8
.7
.7
.7
.7
.9
.7
.7
.7
.7
.7
.6
.6
.6
.6
.6
.6
.6
.6
.6
.6
.6
.6
...
.7
.9
.6
July
.5
.6
.6
.6
.6
.6
.6
.6
.6
.6
.6
.6
.6
.6
.9
.7
.7
.6
.6
.5
.5
.5
.5
.5
.5
.5
.5
.5
.5
.5
.6
.9
.5
Aug.
0.4
.4
.4
.4
.4
__
1.0
1.5
.7
.5
.5
.6
.7
.5
.6
.5
.4
.4
.4
.4
.4
.4
.4
.5
.5
.5
.5
.5
.5
.5
.5
1.5
.4
Sept.
0.5
.5
.5
.5
.5
.5
.5
.5
.5
.5
.4
.4
.4
.5
.4
.4
.4
.4
.5
.5
.61.0
1.3
1.5
1.7
1.8
1.9
2.0
2.3
2.4...
.92.4
.4
Oct.
2.4
2.5
2.7
2.9
3.1
3.3
3.4
3.6
3.8
3.8
3.9
3.9
3.8
3.4
3.1
2.9
2.7
2.8
3.2
3.3
3.0
2.6
2.4
2.5
2.7
3.1
3.8
4.5
4.7
4.9
4.9
3.3
4.9
2.4
Nov.
4.6
4.2
4.1
4.3
4.9
5.7
6.6
7.5
7.4
7.2
7.0
6.8
6.7
7.1
7.7
8.0
7.9
7.8
7.6
7.4
7.2
6.97.2
7.4
7.6
7.8
8.0
8.3
8.5
8.6...
6.9
8.6
4.1
Dec.
8.6
8.5
8.6
8.9
9.4
10.3
10.9
10.6
10.5
5.1
4.0
3.1
2.5
2.0
1.6
1.4
1.2
1.2
1.1
1.0
5.6
9.8
9.7
9.5
8.6
7.5
6.7
7.0
7.8
9.3
10.6
6.5
10.9
1.0
Jan.
11.3
11.5
11.3
11.0
10.9
11.0
11.1
11.1
10.9
10.6
10.4
10.1
10.0
9.8
9.8...
...
...
7.6
7.4
7.1
6.9
6.8
6.7
6.6
6.4
6.2
6.0
9.1
11.5
6.0
Mean Daily Dissolved-Oxygen Concentration in Water From Municipal Weil Seminoie 10 65
Table 31. Mean daily concentrations of dissolved oxygen in water from observation well CRM-3, February 1, 1993, through January 31, 1994[Dissolved-oxygen concentration given in milligrams per liter; , no data]
Day
12345
67
89
10
1112131415
1617181920
2122232425
262728293031
MeanMaximumMinimum
Feb.
__
.
...
3.1
2.41.1.3.2.2
.2
.4...
.6
.6
.5
.5
.5
.5
.5...
.83.1
.2
Mar.
__
...
0.8.4
...
_
.4
.4
.3
.3
.3
.4
.4
.4...
.4
.4
.4
.4
.4
__
1.91.4
.8
.5
.5
.61.9
.3
Apr.
0.5.5.5.5.4
.4
.4
.4
.5
.5
.5
.5
.5
.5
.5
.5
.5
.5
.5
.5...
.8
.7
.6
.6
.6
.6
.6...
.5
.8
.4
May
0.6.5.5.5.5
.5
.5
.5
.5
.5
.5
.5
.4
.4
.4
.4
.4...
.5
.5
.5
.5
.5
.5
.4
.4
.4
.4
.4
.4
.5
.6
.4
June
0.4.4
...
.5
.4
.4
.4
.4
.4
.4
.4
.4
.4
.4
_
.4
.4
.4
.4
.4
.4...
.4
.4
.4
.4
.4
.4
.4
.5
.4
July
...0.9
.4
.4
.4
.4
.4
.4
.4
.4
.4
.4
.4
.4
.4
__
.5
.4
.4
.4
.4
.4
.4
.4
.4
.4
.4
.4
.4
.4
.3
.4
.9
.3
Aug.
0.3.3.3.3.3
.3
.4
.3
.3
.3
.3
.3
.3
.3
.3
.3
.3
.3
.3
.3
.3
.3...
.4
.4
.4
.4
.4
.4
.4
.3
.4
.3
Sept.
0.4.4.4.4.4
.4
.4
.4
.4...
.4
.3
.4
.4
.4
.3
.3
.3
.3
.3
.3
.3
.3...
.4
.3
.3
.3
.3
.3
.3
.4
.3
Oct.
0.3.3.3.3.3
.3
.3
.3
.3
.3
.3
.3
.3
.3
.4
.4
.4
.4
.4
.4
.3
.3
.4
.4
.3
.3
.3
.3
.3
.3
.4
.3
Nov.
0.3.3.3
.3
.3
.3
.3
.3
.2
.3
.3
.3
.3
.3
.3
.3
.3
.3
.3
.3
.3......
.2
.2
.3
.2
.3
.3...
.3
.3
.2
Dec.
0.3.3.2.2.2
__
.3
.3
.3
.3
.3
.3
.3
.3
.3
.3
.3...
.4...
.4
.4
.3
.3
.3
.3
.3
.3
.3
.3
.3
.3
.4
.2
Jan.
0.3.3.3
1.0
.6
.5
.4
.4
.3
.3
.3
.3
.3
.3
.3
.3
.3
.3
.3
__
.2
.3
.3
.3
.3
.3
.3
.3
.3
.2
.3
1.0
.2
66 Effect of the Cedar River on the Quality of the Ground-Water Supply for Cedar Rapids, Iowa
Table 32. Mean daily concentrations of dissolved oxygen in the water from the Cedar Rapids municipal water- treatment plant, February 1, 1993, through January 31, 1994[Dissolved-oxygen concentration given in milligrams per liter; , no data]
Day
12345
6789
10
11121314
15
1617181920
21222324
25
262728293031
MeanMaximumMinimum
Feb. Mar.
0.7.7.5.6.7
.7
.7
.7
.8
1.11 .01.01.0.9
.90.7 1.01.3 .91.1 .9.9 .9
.8 .8
.7 .8
.8 .7
.7 .7
.4
.8.6 .9.9 1.3
1.31.1.8
.8 .91.3 1.3
.4 .5
Apr.
0.6.6.7
1.4.9
.6
1.5
1.41.41.21.0.8
.8
.71.01.41.4
1.41.41.51.61.6
1.6
1.61.41.4
1.21.6
.6
May
1.51.21.21.31.3
1.21.41.52.93.0
2.92.82.92.62.0
2.02.32.52.42.6
1.61.61.51.5
1.51.61.71.71.51.5
1.93.0
1.2
June
1.41.41.41.41.4
1.41.41.51.51.7
1.61.51.41.41.4
1.31.42.93.13.9
3.13.94.53.82.1
1.31.21.21.21.2
1.94.5
1.2
July
1.11.11.11.0.9
1.01.0
_
_
11.210.310.610.7
10.710.19.79.09.3
9.89.59.49.89.38.6
7.111.2
.9
Aug.
8.88.88.48.28.1
__
1.11.01.11.0
1.01.01.0.9.9
.9
.9
.8
.8
.8
.8
.8
.8
.91.1
1.11.11.01.01.01.0
2.28.8
.8
Sept.
1.01.01.0
.9
.9
.9
.9
.9
.9
.9
.91.01.0
.8
.8
.8
.8
.8
.8
.8
.8
.81.01.21.3
1.31.41.11.11.1
1.01.4
.8
Oct.
1.11.0.9
1.01.1
1.01.01.0.8.8
.8
.81.11.41.4
1.31.51.51.41.4
1.31.31.21.11.1
1.11.01.21.51.41.3
1.21.5
.8
Nov.
1.31.31.31.31.2
1.21.21.21.31.8
3.23.63.73.93.5
3.73.22.52.62.7
2.82.7
2.52.2
2.42.42.32.42.4
2.33.9
1.2
Dec.
2.72.72.72.72.7
__
1.71.81.71.7
1.71.61.71.51.6
1.61.6
2.32.4
2.62.62.52.52.4
_ .
2.12.7
1.5
Jan.
__
.
2.8
2.72.52.62.82.8
2.52.42.42.92.4
2.32.52.92.62.5
2.32.82.72.5
2.82.92.92.81.92.2
2.62.9
1.9
Mean Daily Dissolved-Oxygen Concentration in Water From Municipal Water-Treatment Plant 67
Table 33. Numerical range of each primary bio-indicator (particulates) counted per 100 gallons of water[EH, extremely heavy; H, heavy; M, moderate; R, rare; NS, not significant, >, greater than; <, less than; fromVasconcelos and Harris (1992)]
Indicators for surface water1
GiardiaCoccidiaDiatoms
Other algae3Insects/larvaeRotifersPlant debris3
EH
>30
>30>150
>300>100>150>200
H
16- 30
16- 3041 -14996 -29931 - 99
361 -14971 -200
6
61121162126
M- 15
- 15- 40- 95- 30- 60- 70
R NS
1-5 <1
1-5 <1
1-10 <11-20 <11-15 <11-20 <11-25 <1
1 According to U.S.Environmental Protection Agency, 1991, Guidance manual for compliance with the filtration and disinfection requirements for public water systems using surface-water sources, Washington D.C.
2 If Giardia cysts or coccidia are found in any sample, irrespective of volume collected, score as though the sample was counted per 100 gallons.
3 Chlorophyll containing.
Table 34. Relative surface-water risk factors associated with scoring of primary bio-indicators (particulates) present during microscopic particulate analysis of water from the study area[EH, extremely heavy; H, heavy; M, moderate; R, rare; NS, not significant; from Vasconcelos and Harris (1992)]
Indicators forsurface water1
GiardiaCoccidiaDiatomsOther algaeInsects/larvaeRotifersPlant debris
EH
40351614943
H
30301312732
Relative risk factor2
M
2525119521
R
2020
6431
0
NS
0000000
' According to U.S. Environmental Protection Agency, 1991, Guidance manual for compliance with the filtration and disinfection requirements for public water systems using surface-water sources, Washington D.C.
2 Risk of surface-water contamination: greater than or equal to 20, high risk; 10-19, moderate risk; 0-9 low risk.
68 Effect of the Cedar River on the Quality of the Ground-Water Supply for Cedar Rapida, Iowa