Results
from the National Water Monitoring Day Snapshot:
Iowa's Picture
Iowa Department of Natural Resources - Iowa Geological Survey
IOWATER Program
109 Trowbridge Hall
Iowa City, IA 52242-1319
(319)335-1598; lseigley@igsb.uiowa.edu
On
October 18, 2002, IOWATER monitors all over Iowa dipped test strips,
transparency tubes, and thermometers into streams in an effort to assess the
quality of streams across Iowa in the first statewide snapshot sampling event.
A snapshot sampling is when multiple sites throughout a geographic area,
such as a watershed or county, are sampled within a short period of time (e.g.,
eight hours). A snapshot provides a
picture of water quality at one point in time and can be completed:
The
samplings can be done:
Iowa's
statewide snapshot sampling was held in conjunction with National Water
Monitoring Day. A total of 68 sites
were sampled across Iowa. This
paper summarizes results from Iowa’s portion of the National Monitoring Day
Snapshot, and compares the data to streams sampled statewide during October as
part of Iowa's long-term stream network. The
attached maps show results from the National Monitoring Day snapshot sampling
and the statewide network for October 2002.
National
Water Monitoring Day Snapshot
October
18, 2002, marked the 30th anniversary of the passage of the Clean Water Act.
To celebrate the event, volunteer monitors from across the U.S. were
encouraged to test their waters as part of National Water Monitoring Day. The
monitoring event was to provide a snapshot in time of water resources in the
U.S. The event, the first of what
is intended to be an annual event, was coordinated by America's Clean Water
Foundation. Nationally, monitors were encouraged to measure water
temperature, pH, dissolved oxygen, and water clarity/turbidity.
In
Iowa, IOWATER monitors were encouraged to participate in National Water
Monitoring Day by monitoring their regular sites between 10 am and 2 pm on
October 18 and to complete any or all of the IOWATER field assessments. Data
collected were then submitted to the IOWATER database.
Results from the sampling were intended to provide a picture in time of
water quality in Iowa. (Note: The
results below include only data submitted to the IOWATER database and none of
the data submitted to the National Water Monitoring Day website.
Since not all IOWATER monitors were able to sample on Friday October 18,
this summary includes data submitted to the IOWATER database for sites monitored
from October 16 through October 20.)
 Figure 1. Location of sites monitored. |
A
total of 68 sites were monitored in 24 Iowa counties (Figure 1); three of the 68
stream sites monitored were dry. Two
of the dry sites were in Lucas County in southern Iowa and have been dry since
July 31, 2002 (note: since these
two sites are relatively close to each other, the two sites appear as one site
on the map); the other dry site was in Black Hawk County.
Table 1 summarizes the results from the sampling.
All samples were collected using standard IOWATER methods.
For 10 sites, the October 18 sampling represented the first time these
stream sites were sampled. All
other sites have been monitored before, with some having been monitored 25 times
or more.
Table
1. IOWATER Statewide Snapshot
Sampling Results for October 18, 2002.
|
Parameter |
Unit |
#
of samples |
Min
Value |
Percentiles |
Max
Value |
||
|
25th |
50th |
75th |
|||||
|
Water
Temperature |
degrees
F |
63 |
29 |
45 |
48 |
51 |
59 |
|
pH |
pH
units |
64 |
7 |
8 |
8 |
9 |
9 |
|
Dissolved
Oxygen |
mg/L |
65 |
4 |
8 |
8 |
10 |
12 |
|
Nitrite-N |
mg/L |
64 |
0 |
0 |
0 |
0.15 |
1 |
|
Nitrate-N |
mg/L |
65 |
0 |
1 |
2 |
5 |
20 |
|
Chloride |
mg/L |
30 |
<25 |
<25 |
30 |
36 |
191 |
|
Transparency |
centimeters |
59 |
17 |
51 |
60 |
60 |
60* |
|
Orthophosphorus |
mg/L |
63 |
0 |
0.1 |
0.2 |
0.3 |
5.0 |
Note:
Three sites that were monitored were dry:
two in Lucas County and one in Black Hawk County.
* The maximum transparency reading that can be recorded using the
transparency tube is 60 centimeters.
pH
pH
is a measure of a water's acidity. Changes
in pH can be caused by atmospheric deposition of acid rain, the types of soils
and bedrock that the water comes in contact with, wastewater discharges, and
acid mine drainage. A pH of 7 is
neutral; pH values greater than 7 are alkaline or basic, while a pH less than 7
is acidic.
pH
levels from the IOWATER snapshot monitoring event varied from 7 to 9, with an
average of 8 (Figure 2). The
statewide stream network had pH values ranging from 7.2 to 8.9 for October 2002,
with an average of 8.3. pH levels
in Iowa streams typically fall within a very narrow range of 8.1 to 8.4.
Of the 64 streams sampled as part of the snapshot sampling, 78% had a pH
of 8 or 9.
 Figure 2. pH results. |
Chloride
Chloride
is a component of salt, and is a measure of human or animal waste inputs to a
stream. Potential sources of
chloride to a stream include direct input from livestock, septic system inputs,
and/or discharge from municipal wastewater facilities. During winter months, elevated chloride levels in streams may
occur as a result of road salt runoff to nearby streams.
Only
30 sites were sampled for chloride (Figure 3).
The fewer number of chloride results reflects the difference in level of
IOWATER training received by those who participated in the snapshot sampling.
Chloride is an IOWATER Level 2 parameter, and only half of those who
participated in the snapshot sampling have completed IOWATER Level 2 training.
Chloride concentrations ranged from below detection (<25 mg/L) to 191
mg/L. The
average chloride concentration was 30 mg/L, and is similar to chloride levels
reported from the statewide stream network monitored during October 2002.
Average chloride concentration for the statewide network for October
2002 was 23 mg/L, and concentrations ranged from 6.6 to 110 mg/L.
Three
sites that were sampled as part of the IOWATER Monitoring Day Snapshot, a site
in Black Hawk County, another in Dubuque County, and a third site in Johnson
County, reported elevated chloride concentrations of 92, 150 and 191 mg/L,
respectively. The site in Black
Hawk County has been sampled on a monthly basis for the past year, and the 92
mg/L is the highest chloride level reported for this site to date.
The site in Dubuque County has reported chloride concentrations above 100
mg/L for the past year. The IOWATER
monitor for this site has noted livestock adjacent to this stream site.
The site in Johnson County is downstream of a municipal wastewater
facility. This is the first time
this site has been sampled, although this site has been used for IOWATER Level 2
workshops, and elevated chloride has been noted during those workshops.
An elevated orthophosphorus value of 3 mg/L was also recorded at this
site.
 Figure 3. Chloride results. |
Orthophosphorus
Orthophosphorus
is a necessary nutrient for plant growth. Too
much phosphorus in surface waters, however, can cause nutrient enrichment,
increasing aquatic plant growth, and changing the types of plants and animals
that live in a stream. Sources of
orthophosphorus include certain soils and bedrock; human and animal wastes;
detergents; decomposing plants; and runoff from fertilized lawns and cropland.
Orthophosphorus
concentrations ranged from 0 to 5.0 mg/L (Figure 4). The average concentration was 0.2 mg/L. Six sites reported orthophosphorus concentrations of
1.0 mg/L or higher. These sites
were located in Black Hawk, Johnson, Linn, Polk, and Sioux counties. The site in Black Hawk County had an orthophosphorus value of
1.0 mg/L, a concentration that has been recorded at this site previously.
The orthophosphorus level in the Johnson County stream was 3.0 mg/L.
This was the first time this site has been monitored.
The site is located downstream of a municipal wastewater outfall, and
also reported elevated chloride levels (191 mg/L). The Linn County site had a value of 5.0 mg/L, a level that
has also been measured at this site before.
Two sites in Polk County had an orthophosphorus concentration of 1.0
mg/L. Both sites also had a
nitrate-N value of 5 mg/L. The site
in Sioux County has been monitored seven times since August 2000.
Each time the site has been sampled, orthophosphorus values have been
greater than 1 mg/L. Nitrate-N concentrations tend to be elevated at this site
also, ranging from 2-10 mg/L. This
site receives runoff or discharge from a golf course, a municipal wastewater
facility, and a meat packing plant facility.
All of these facilities are located in the watershed above the site, and
all are within four miles of the monitoring site.
The
average orthophosphorus concentration reported from the statewide network of
stream sites that were professionally monitored during October 2002 was 0.12
mg/L. Orthophosphorus
concentrations ranged from below the detection limit of 0.05 mg/L to 1.2 mg/L,
with the higher concentrations scattered throughout all of Iowa.
 Figure 4. Othophosphorus results. |
Dissolved
Oxygen
Dissolved
oxygen levels in a stream can be affected by a number of variables, including
water temperature, season of the year or time of day, stream flow, presence of
aquatic plants, dissolved or suspended solids, and human impacts.
Oxygen enters a stream through diffusion from the surrounding air and as
a product of photosynthesis from aquatic plants.
Oxygen in a stream can be consumed through respiration by aquatic plants
and animals, and by the decomposition of organic matter.
The
average dissolved oxygen for the sites sampled was 8 mg/L (Figure 5); the lowest
dissolved oxygen value was 4 mg/L, recorded at a site in Mitchell County.
This was the first time that dissolved oxygen had been measured at this
site. Another site in Johnson County had a reading of 5 mg/L. This
site has been monitored for dissolved oxygen on 14 different occasions, and low
dissolved oxygen concentrations have been recorded previously at this site.
Eight sites reported a dissolved oxygen concentration of 6 mg/L.
These sites were scattered throughout the northeast quarter of Iowa and
included one site in Polk County. For most of these sites, previous monitoring
has reported similarly low dissolved oxygen levels.
Average
dissolved oxygen concentration for the streams monitored professionally
statewide during October 2002 was 8.9 mg/L.
Dissolved oxygen concentrations ranged from 5.3 mg/L to 13.0 mg/L, with
all sites reporting values greater than 5 mg/L. Sites with dissolved oxygen greater than 10 mg/L were
primarily located in the northern one-third of Iowa.
 Figure 5. Dissolved oxygen results. |
Water
Temperature
Water
temperature affects many of the biological, chemical, and physical processes in
a stream, including the amount of oxygen gas that can dissolve in water, the
rate of photosynthesis by algae and plants, as well as the metabolic rate of
aquatic animals. Human activities
can adversely raise stream temperatures by releasing warmed water into a stream.
These human induced increases in water temperature are known as thermal
pollution. Examples of thermal pollution include industry discharges or
runoff from paved surfaces; removal of trees from along streams, thus allowing
direct sunlight to warm the water; or soil erosion, which causes an increase in
suspended particles in water. These
particles are able to absorb heat from the sun and increase water temperature.
Water
temperatures from the snapshot ranged from 29 to 59 degrees Fahrenheit and the
average was 48 (Figure 6). Most of
the sites that had lower water temperatures were located in the Squaw Creek
Watershed near Ames in Story County
The
average temperature reported from the statewide network of stream sites that
were professionally monitored during October 2002 was 60 degrees Fahrenheit.
Water temperature ranged from 46 to 74 degrees Fahrenheit, with the
warmer water temperatures primarily located in streams in the southern half of
Iowa. The difference in temperatures between the IOWATER snapshot
sampling and the statewide network of streams may be related to when each
sampling occurred. The statewide
network was sampled during the first two weeks of October, while the IOWATER
sampling occurred the latter part of the third week in October.
Statewide, air temperatures were above normal for the end of September
and beginning of October, but quickly declined to below normal for most of
October. October was the 5th
coldest October on record based on 130 years of weather record in Iowa (http://www.agriculture.state.ia.us/climatology/weathersum1002.htm).
 Figure 6. Water temperature results. |
Nitrite-N
and Nitrate-N
Nitrogen
is a necessary nutrient for plant growth, and includes both nitrite- and
nitrate-nitrogen. Too much nitrogen
in surface waters, however, can cause nutrient enrichment, increasing aquatic
plant growth and changing the types of plants and animals that live in a stream.
Sources of nitrogen include soils; human and animal wastes; decomposing
plants; and fertilizer runoff from golf course, lawns, and cropland.
For
the snapshot sampling, nitrite-N concentrations ranged from 0 to 1 mg/L (Figure
7). The majority of sites had 0
mg/L or a very low concentration. More
than 65% of the sites had 0 mg/L; only 5% of the sites had nitrite-N greater
than 0.15 mg/L. Of the sites with
elevated nitrite-N concentrations, the site in Johnson County usually has low
(0.15 to 0.30 mg/L), but detectable levels of nitrite-N. A site in Sac County had a nitrite-N concentration of 1 mg/L;
very few samples have been collected at this site, and the 1 mg/L is the highest
concentration to date.
 Figure 7. Nitrite-N results. |
Nitrate-N
concentrations ranged from 0 to 20 mg/L, with an average of 2 mg/L (Figure 8).
The highest reported nitrate-N concentration was 20 mg/L at a site in
Cerro Gordo County near Mason City. This
concentration was the highest nitrate-N value ever measured for this site.
Three sites had nitrate-N concentrations of 10 mg/L:
one in Sioux County in northwest Iowa; a site in Story County in central
Iowa; and a site in Fayette County in northeast Iowa.
Elevated nitrate-N has been reported previously for the site in Sioux
County, whereas the nitrate-N result from the Fayette County site was the
highest recorded to date for that site. The
site in Story County has had elevated nitrate most of this year, with a high of
20 mg/L from July 2002.
 Figure 8. Nitrate-N results. |
Transparency
Transparency
is a measure of water clarity and is affected by the amount of material
suspended in water. As more
material is suspended in water, less light can pass through the water, making it
less transparent (or more turbid). These
materials include soil, algae, plankton, and microbes.
A
cluster of sites monitored in the Squaw Creek Watershed near Ames in Story
County and another group of sites in and around the Shell Rock River area of
Butler and Floyd counties all reported transparency values greater than 40
centimeters. Water transparency was
high not only for these areas, but also for the majority of streams sampled, as
75% of the sites had a transparency of 50 centimeters or greater (Table 1;
Figure 9). This was not unusual
given the time of year and lack of rainfall prior to sampling.
For one site in Butler County, the transparency reading of 51 centimeters
was the highest reported for this site to date. The lowest transparency values
were 17 and 19 centimeters for sites in Buchanan and Johnson counties,
respectively. For the site in
Butler County, 17 centimeters was one of the lower values reported for this
site. For the site in Johnson
County, past monitoring has reported similar low transparency measurements.
Transparency
is not measured as part of the statewide network of streams, rather, turbidity
is used as an indicator of the amount of sediment in the stream.
Turbidity values ranged from 1.2 to 690 Nephelometric Turbidity Units (NTU),
and the average was 20 NTU. (Note:
The higher the turbidity reading, the more suspended material is in the
water, compared to transparency where a lower transparency reading means that
more suspended material is in the water.)
The higher turbidity values were recorded at streams in western Iowa and
across the southern half of Iowa, while the lowest turbidity values were for
streams in northeast Iowa.
Figure 9. Water transparency results. |
Future Statewide
Snapshots
The
IOWATER program gratefully acknowledges everyone who took their time to monitor
sites as part of the statewide snapshot sampling. We plan to build upon the first statewide snapshot sampling
by coordinating a biannual statewide snapshot sampling in the spring and fall of
every year. Stay tuned to the Iowa
Citizen Monitor, IOWATER's newsletter, for more details.
The spring 2003 snapshot sampling is scheduled for Saturday May 24, 2003,
and the fall sampling will be conducted again in October, in conjunction with
National Water Monitoring Day.
Acknowledgements
Thanks
to the following for their participation in the National Monitoring Day Snapshot
Sampling and for submitting data to the IOWATER database:
Jean Hagert Dow; Dieter Dellmann; James Heinz and
Jefferson Junior High School students; Bruce Burroughs; Shirley Van
Eschen; Andria Cossolotto and Atlantic High School students; Sam Hamilton-Poore;
Kerry Krogh; Dana Lawrence; Cheri Hufford; Coleen Hughes and Dubuque Wahlert
High School students; Charlie Winterwood; Richard Worm;
Dave Carnahan and Table Mound Elementary School students; Lowell Dibble;
John Black and Monticello High School Environmental Science students; Kim and
Marsha Francisco; Bill Helgen; Irlanda Hoffman; Dale Adams; Debra Lyons and JMS
8th grade student; Charles Sayre and his wife; Curtis Lundy; Evan Degroot; Erwin
Klass; Ken Shaw; Brian Vobr, Chad Kostohryz, and Brandon Riha of Crestwood High
School Natural Resources class; Robert Basset; Gaylan and Lloyd Crim; Bell
Tubbs; Karen and David Manning; Cheryl, Tyler, and Dillon Waskow; Lou Corones;
Lisa Horsch and Block 2 Science; Bill Schwarz and Prairie High School students;
Eric Dralle, Tim Ott, Jen Linskey, Steph Chase, Kelly Chisholm; James Martin,
Kristen L., Jason H., Kristen G; and Vicki Wilson.
NOTE: The maps below show the October 2002 results from the 85 stream sites that are monitored on a monthly basis as part of Iowa's Ambient Water Monitoring Program. These maps are included to provide perspective for the National Water Monitoring Day results.
|
|
|
|
 Ambient Water Monitoring Program results for October 2002 - chloride. |
|
|
 Ambient Water Monitoring Program results for October 2002 - orthophosphorus. |
|
|
 Ambient Water Monitoring Program results for October 2002 - dissolved oxygen. |
|
|
 Ambient Water Monitoring Program results for October 2002 - water temperature. |
|
|
 Ambient Water Monitoring Program results for October 2002 - nitrate-N. |
|
|
 Ambient Water Monitoring Program results for October 2002 - turbidity. |
