WATER RESOURCES BULLETIN
VOL. 15, NO. 4
AMERICAN WATER RESOURCES ASSOCIATION
AUGUST 1979
CONCENTRATION AND SOURCES OF FECAL
AND ORGANIC POLLUTION IN AN
AGRICULTURAL WATERSHED'
Daniel R . Dudley and James R . Karr'
ABSTRACT: Fecal contamination and organic pollution of an agricultural drainage in northeast Indiana was high. Bacterial counts (total coliform, TC; fecal coliform, FC; and fecal
streptococcus, FS) and biochemical oxygen demand (BOD) were used to assess waste concentrations. Coliform counts indicated that sections of the drainage receiving septic effluent had
waste concentrations far in excess of public health standards (mean FC = 550,000/100 ml).
Areas of drainage remote from septic tank pollution were found to occasionally meet federal
public health standards for whole body contact recreation but generally these areas had twice
the allowable limit of 200 FC/lOO ml. Bacterial contamination was highest during runoff
events when the median values for TC, FC, and FS were 5,3, and 17 times greater, respectively,
than the median values during low stream discharge. Surface flows carried contaminants from
unconfined livestock operations and fecally contiminated sediment was transported by high
waters. During one runoff event a BOD loading of 36.7 kg/km2 was recorded and the peak
BOD concentration observed was 16 mg/l. A discharge of liquid manure from a confined livestock operation caused a major fish kill. Pollution from septic tanks and unconfined livestock
is greatest at high stream discharge when dilution reduces the impact on aquatic life.
(KEY TERMS: bacterial pollution; BOD; agricultural runoff; coliform bacteria; fish kill;water
pollution sources.)
INTRODUCTION
Organic pollution, especially in the form of fecal contamination, is a concern for
several reasons. Potential human health hazards from water borne pathogens can exist in
any fecally contaminated water but the risks have been found to increase substantially
when fecal coliforms are above 200 counts per 100 ml (Geldreich, 1970). Low to
moderate levels of organic pollution influence the type of aquatic community present in a
stream and gross organic pollution represents a threat to the survival of downstream fish
populations (Hynes, 1960). Although the problem of organic pollution in agricultural
areas has been recognized for some time, the traditional concerns of water pollution control have centered on large municipal and other point sources of organic pollution. Regulations calling for water quality planning in non-point areas necessitates an evaluation
of the degree of organic and fecal pollution in rural areas.
'Paper No. 78044 of the Water Resources Bulletin. Discussions are open until April 1, 1980.
'Respectively, Aquatic Biologist, Allen County Soil and Water Conservation District, 2010 Inwood,
Fort Wayne, Indiana 46805 ; and Associate Professor, Department of Ecology, Ethology, and Evolution, University of Illinois, Champaign, Illinois 61 820.
91 1
Dudley and Karr
Organic pollution and fecal contamination has been documented in runoff from barnlots (White, 1972), dairy farms (Janzen, et al., 1974), cropland (Weidner, et al., 1969;
Smith and Douglas, 1973;Burwell, et ul., 1974; Harms, et al., 1975), andseptic tank
drainfield systems (Reneau, et al., 1975). Large numbers of fecal coliforms reached an
estuary of Chesapeake Bay from a rural watershed (Faust, 1976). Both urban and agricultural watersheds in New Jersey contained high levels of organic pollution (Yu, et al.,
1975).
In this paper we present the results of a two year study of bacterial contamination
and biochemical oxygen demand (BOD) in a 48.5 km2 (12,000acre) agricultural watershed. Probable sources of contamination are discussed and contamination levels are compared with federal guidelines.
METHODS AND MATERIALS
Study Area
The Black Creek drainage in Allen County, Indiana (15 miles NE of Fort Wayne,
Indiana) has been the subject of an intensive demonstration and research project designed
to reduce soil erosion in an agricultural watershed. The project was designed to investigate the relationship between soil conservation practices and water quality. Results of
agricultural, economic, and other biological studies in the watershed can be found in the
Black Creek final report (Morrison,et al., 1977).
The Black Creek watershed is a 48.5 km2 (12,000acre) drainage within the Maumee
River basin and is representative of the soils and land use of the larger Maumee basin.
Soils range from the silty clay loam of the Fort Wayne moraine to the medium and fine
textured, high clay soils associated with glacial Lake Maumee. Eighty percent of the
Black Creek watershed is cropland while 4 percent is urban. Woodland and pasture make
up the remaining area. There are three areas of differing topographic relief within the
watershed: the rolling upland of the Fort Wayne moraine (2-6% slopes), the glacial lake
bed area (0-2% slopes), and a transitional area between these two known as the beach
ridge (Figure 1). Farms on the lake plain area are generally more progressive than farms
on poorer quality upland areas. An Amish community farms 60 percent of the upland
area without the use of modem equipment. Typically, an Amish farm has 15-20head of
dairy cattle, 10-15work horses, and 20-30head of hogs. Therefore, large numbers of
livestock in pasture or barnlots contribute to the organic pollution of the upper Dreisbach
and Wertz Drains (Figure 1). In contrast, more contemporary lake plain farms have confined livestock feeding operations that are equipped with waste holding facilities. Under
proper management, these are not a major source of organic pollution in Black Creek.
Domestic waste from a rural community and recent “strip” housing developments
along major roads are another source of organic pollution in the Black Creek watershed.
Homeowners both in the community of Harlan (population 600) and throughout the
watershed rely on septic tank systems for treatment of sewage. The slow percolation
rates of heavy clay soils limit the effectiveness of these systems. Therefore, a high percentage of the septic tanks have off-lot discharges into nearby streams or tile systems.
912
Organic Pollution in an Agricultural Watershed
Figure 1. Map of the Black Creek Watershed Showing Location of
Sampling Stations and Late Summer Flow Conditions.
Bacteriological Sampling
Water samples for microbiological analysis were collected from 42 stations (22 surface, 20 tile) during the period March 1976 through May 1977 (Figure 1). Samples were
taken at three month intervals at stations where water was present. Many stations could
not be sampled on one or more of the six sampling dates because of dry conditions.
Nineteen surface water stations were located in the Black Creek watershed at the lower
end of tributary drains which enter Black Creek and at approximately one mile intervals
along Black Creek, the Richelderfer Drain, and the Dreisbach Drain. An additional station was located on the Wertz Drain. Three stations outside the watershed included two
on Wann Ditch east of the Black Creek Study Area at Killian Road and one on the
Maumee River at Route 101.
Tile systems were selected t o represent the major soil types in the watershed. Because
of a severe drought in 1976-77, 55 of 120 potential samples were not obtained because
tiles were not flowing. Six tile lines connected to septic tank systems flowed regularly.
All tile systems sampled in this study were also sampled in another phase of the project
for suspended solids and nitrogen and phosphorus fractions (Morrison, et al., 1977).
Samples were collected in sterilized 100 ml glass bottles by immersing them at the
water’s surface. Generally a single sample was collected at each station although occasionally triplicate samples were collected to establish sampling variability. Testing procedures were initiated five hours or less after sample collection. The Allen County Board
of Health laboratory conducted the testing. The membrane filter technique was used
913
Dudley and Karl
following Standard Methods (American Public Health Association, 1971) and the recommendations of the Millipore Company. After serial dilution of the samples, plates were
inoculated. The media used were m-Endo MF broth (Millipore), m-FC broth (Millipore)
and KF streptococcus agar (Difco) for total coliform, fecal coliform and fecal streptococcus tests, respectively. The incubation and counting procedures outlined in Standard
Methods were followed. Throughout this report the bacterial concentrations are expressed on the basis of counts per 100 ml of water.
BOD Sampling
Samples for biochemical oxygen demand (BOD) analysis were collected during a major
storm event on June 30, 1977 (7.1 an rainfall). Sample sites were selected to represent
a variety of conditions: for example, urban vs. agricultural, Amish vs. conventional farms.
Composite samples were also made from water collected by automated pump samplers at
two locations (Figure 1). These automated stations were equipped with calibrated weirs
and stream stage recorders and provided data on stream discharge. At stream stages above
one foot, the automated pump samplers collected water samples every 30 minutes during
the course of the storm event. Composite samples for BOD analysis were made at the end
of the event by combining 50 ml of water from each sample taken by the pump sampler.
BOD loading was calculated by multiplying the BOD concentration of the composite
sample by the volume of runoff measured during the time interval the pump samplers
were operating.
In addition, six grab samples were collected for BOD analysis and ammonia-N analysis
during a major fish kill, September 29, 1977. Samples were taken from the tile line discharging the pollutant and at upstream and downstream locations.
Samples for BOD studies were collected in 2 liter polyethylene containers and refrigerated until laboratory set-up was initiated the next day. Laboratory analysis for BOD
and ammoniaN was done by Pollution Control Systems, Inc. (Laotto, Indiana) following
the procedures of Standard Methods (American Public Health Association, 1971).
RESULTS
Sample Variability
The high level of variability in bacterial counts (C.V. 30 to 75) and incomplete data
records during a dry period suggests caution in examination of data from individual stations. Consequently, we shall avoid detailed station-by-station analysis and concentrate
on groups of similar stations. Further, since flow volumes varied among the sample dates
two flow classes were defined: low flow when no surface runoff could be detected and
high flow when there was substantial surface runoff (Table 1). Among the six sample
dates five were low and one was high.
Bacterial Counts in Surface Waters
Sixty-five samples were collected at low flow and 20 samples were taken at high flow
conditions (Table 2). Mean values are high because of very high counts near septic tank
outfalls. Therefore, we use median values as more representative of bacterial contamination. Without exception bacterial counts were higher under high flow than under low
flow conditions (Table 2).
914
Organic Pollution in an Agricultural Watershed
TABLE 1. Sampling Dates and Stream Discharges at Two Sites
in the Black Creek Watershed (discharge class is based on the
occurrence of surface runoff from agricultural land).
Average Daily Discharge (m3/sec.)
Discharge
am
Site 2
Site 6
29 March 1976
Low
0.048
0.025
7 June 1976
LOW
0.008
0.004
23 August 1976
Low
0.004
0.000
29 November 1976
Low
0.000
0.002
28 March 1977
High
1.077
0.775
3 1 March 1977
Low
0.001
0.001
Date
TABLE 2. Bacterial Counts (count/100 ml water) Observed in the
Black Creek Watershed at Low and High Stream Discharge.
Total
Coliform
Fecal
Cdiorm
Range
1002,600,000
2,600,000
Median
Mean
3,500
165,000
1,000
109,000
Fecal
Streptococcus
Low Stream Discharge*
0-
0890,000
200
19,000
High Stream Discharge**
Range
60092,800
0 -36,000
10,000
Median
Mean
18,000
26,000
3,400
4,900
3,400
4,200
0-
*Data from 65 observations taken at 20 surface water stations on 5 sampling dates in 1976 and 1977.
**Data from 20 observations taken at 20 surface water stations on 28 March 1977.
When not carrying storm runoff, some streams in the Black Creek watershed maintained a base discharge from ground water, others ceased to have any discharge and in the
summer months became a series of isolated pools, and a few sections of stream had an
915
Dudley and Karr
intermittent flow arising from domestic waste effluent (Figure 1). To facilitate comparisons among stations, six groups of stations were identified on the basis of proximity of
sewage outfalls and discharge regime during low flow periods (Figure 2). There are n o
significant differences among the group means even when stations are so grouped. However, the frequency distribution of six levels of bacterial contamination illustrates differences among the groups (Figure 2). Groups D and A, stations with high levels of organic pollution, had broad distributions of total colifonn counts and high median values.
The moderately polluted groups, B and E, also had wide distributions but much lower
median total coliform counts. The remaining two groups, F and C, had low levels of pollution, a narrower distribution of total coliform counts and still lower median values. The
distribution of fecal coliform counts was very similar to that for total coliforms. Fecal
streptococcus contamination was slight except in the highly polluted areas where median
counts were 5,050 (Group D) and 1,600 (Group A). The remaining groups of stations
had median counts less than 200 fecal streptococci per 100 ml water.
At low stream discharge the degree of fecal contamination was primarily dependent
upon the proximity of sewage outfalls and not the flow regime in the stream. The fecal
coliform counts indicate that sections of the Black Creek drainage that received septic
waste had fecal contamination far in excess of any public health standards. Areas of the
drainage remote from septic tank pollution occasionally met federal public health standards for whole body contact recreation (Fed. Wat. PCA 1968) but generally these areas
had twice the allowable limit of 200 fecal coliforms per 100 ml of water. At low stream
discharge total coliform concentrations were above the maximum acceptable levels
(10,000/100 ml) only at septic tank outfalls.
On March 28, 1977, there was considerable surface runoff from agricultural land and
stream discharge in Black Creek was high (0.775 m3/sec.). Mean and median bacterial
counts were not greatly different because septic tank effluent in the badly polluted
stream sections was being diluted (Table 2). The median values for total coliform, fecal
coliform, and fecal streptococcus counts were 5 , 3, and 17 times greater, respectively,
than the median values during low stream discharge (Table 2).
Increases in total and fecal coliform counts were caused by higher counts at stations on
Black Creek downstream of Harlan. Tributary drains not influenced by Harlan showed
only a slight increase in coliform contamination over low stream discharge levels (Table3);
these data suggest that storm runoff from agricultural land is not the major source of coliforms. Rather, the source of high coliform counts in high flow periods is material deposited as bottom sediment at septic tank outfalls. This sediment is transported downstream
during storm events.
Fecal streptococcus contamination increased at all stations on the watershed during
high flow. The increase was particularly strong above Harlan on the Dreisbach Drain. A
grassed waterway and an open ditch in this section of the watershed carried fecal streptococcus counts from 5,000 to 10,000 per 100 ml water. Slightly lower levels of contamination (3,000 - 9,000) were maintained along the lower Dreisbach Drain, the
Richelderfer Drain and Black Creek. Other tributary drains had from 0 to 3,500 fecal
streptococcus per 100 ml water. Thus the agricultural area of upper Dreisbach Drain
and the town of Harlan were the major identifiable areas of fecal streptococcus contamination at high stream discharge. In these areas contamination was more than an
order of magnitude greater than the levels of pollution observed at low stream discharge.
We conclude that runoff from barnlots and/or pastures of the noncontemporary (Amish)
916
Organic Pollution in an Agricultural Watershed
livestock operations was responsible for substantial fecal pollution of storm runoff in the
Black Creek watershed.
Total Coliform
Fecal Coliform
Fecal Streptococcus
0,9
10
0.4
C
5
ul
C
.-0
+
a
F
5
B a c t e r i a l Count Classes
Figure 2. The Frequency of Six Ranges of Bacterial Counts Found in Different
Areas of the Black Creek Watershed (station groupings A-F) a t Low Stream Discharge.
[The range of the bacterial count classes are: 1, 0-100; 2, 100-1,000; 3, 1,000-10,000;
4, 10,000-50,000; 5 , 50,000-500.000; 6 ,
500,000. Grouping A - Isolated pool, high
pollution; B - Isolated pool, moderate pollution; C - Isolated pool, low pollution; D Intermittent flow, high pollution; E - Intermittent flow, moderate pollution; F - Base flow,
low pollution. Numbers (x -lo3) indicate mean (upper) and median (lower) bacterial counts.]
>
917
Dudley and K a r ~
TABLE 3. Median Values for Total Coliform and Fecal Coliform Counts at
Stations Downstream from the Town of Harlan and at Stations not Influenced
by Harlan or Any Other Large Source of Septic Pollution.
Total Cdiform
Fecal Coliform
fish
LOW
High
Discharge
Dipcharge
Discharge
Discharge
Stations Downstream
of Harlan
2,850
32,000
600
5,300
Stations Not Influenced
by Harlan
1,800
2,500
500
700
LOW
For comparative purposes surface water samples were collected from the Maumee
River and Wann Ditch. The Maumee River is the receiving body for Black Creek. Wann
Ditch is a small stream adjacent to the Black Creek watershed which lacks any concentrated urban area. Wann Creek is comparable to Sampling Group C of Black Creek.
Bacterial counts were similar to those reported from stations in Group C including increased fecal streptococcus counts at high stream discharge.
Counts from the Maumee River were wide ranging, probably being a function of discharge, as the highest counts were recorded in the spring. Fecal coliforms were generally
fairly low (200-500 counts per 100 ml.) but at high discharge the counts increased an
order of magnitude (4,000-15,000). Fecal streptococci were detected only once at the
Maumee River station during a period of high stream discharge (March 20,1977). Compared to the waters of the Black Creek drainage the Maumee River had approximately the
same concentration of total coliforms but lower concentrations of fecal coliforms and
fecal streptococcus (excluding periods of high stream flow).
Bacterial Counts in Subsurface Water
Tile drainage samples derive from high or low flow conditions and from septically or
not-septically polluted tile systems (Table 4). Predictably, septically polluted tiles had
high average values during low flow when there was very little dilution of septic waste by
natural drainage water. At high flows these same tiles carried far lower concentrations of
bacteria because of dilution by subsurface drainage water. Nonseptically polluted tile
systems had low levels of coliform contamination that remained unaffected by discharge
rates. Total coliform counts were very similar at high and low discharge; a small increase
in fecal coliform concentrations at high flow resulted from high values at two tiles with
surface water inlets.
Fecal streptococcus contamination of nonseptically polluted tile systems increased at
high flow for most stations. At low flow, only 1 of 14 stations had counts over 100.
At high flow 10 of 14 stations had fecal streptococcus counts between 100 and 500 while
two tiles with surface water inlets had counts an order of magnitude greater. Nonseptically polluted tile systems were an identifiable source of fecal streptococcus contamination at high stream discharge. However, the degree of contamination was low and fecal
918
Organic Pollution in an Agricultural Watershed
coliforms were generally not detected suggesting fecal material was not the contaminating source. Instead, this bacterial contamination was probably caused by Streptococcus
faecalis var. liquifaciens, a common organism on vegetation and in soil that is frequently
isolated from good quality water (Geldreich and Kenner, 1969).
TABLE 4. The Mean Total Coliform (TC), Fecal Coliform (FC) and Fecal
Streptococcus (FS) Counts for Six Septically Polluted and Fourteen NotSeptically Polluted Tile Drainage Outlets (N = number of samples).
Septically Polluted
Low Flow
TC
FC
FS
Not-Septically Polluted
Mean
N
Mean
N
330,000
6 1,000
21
21
21
2,300
60
10
24
25
25
5
2,300
400
2,200
14
14
14
30,000
High Flow
TC
FC
FS
9,700
2,300
5,900
5
5
Sources of Contamination
An indication of the sources of fecal pollution is given by the fecal coliform/fecal
streptococcus ratio (FC/FS). A ratio greater than 4 indicates human sources of pollution,
a ratio less than 0.7 indicates an animal source, and ratios between 0.7 and 4 indicate
combined human and animal fecal pollution (Geldreich and Kenner, 1969). At low flows
in the Black Creek watershed, the dominant source of fecal contamination was human
but there was a significant (x2 = 22.6, p < 0.01) shift from human to mixed human and
animal sources of pollution when discharge increased. This shows that livestock operations had a substantial impact on the fecal contamination of storm water runoff. Surface
water stations in the upper Dreisbach agricultural area exhibited the greatest degree of
fecal contamination from livestock while surface water stations in other areas showed
either livestock sources or mixed human and animal sources.
BOD Concentrations
Paired samples from watersheds of about 50 acres in the rolling upland yielded high
BOD concentrations from Amish land relative to land with conventional farming methods
(Table 5). Apparently, unconfined livestock in the Amish area substantially increased the
amount of organic matter in surface runoff.
One sample, taken from a large tile outlet with surface inlets near a contemporary confined livestock-feedingoperation, had exceptionally high BOD (480 mgll). This is roughly
equivalent to raw sewage (Hynes, 1960), even though the feedlot is equipped with
properly designed waste holding facilities. Apparently, the control of manure wastes is
less than 100% effective. The tile outlet was sampled during the initial phase of the storm
919
Dudley and Karr
and surface runoff was just beginning so the volume of discharge was small. It is doubtful that BOD concentrations remained this high during peak storm runoff because dilution
is increased. In terms of total BOD loading, this type of runoff from a confined feeding
operation cannot be considered a major source within the watershed. However, such
sources may raise BOD concentrations in streams above the concentrations found in runoff from cropland. Also, highly concentrated organic matter delivered to streams in this
manner could be locally damaging if rainfall and runoff are not sufficient to dilute and
flush away the organic matter at the outfall.
TABLE 5. Biochemical Oxygen Demand (BOD) Found at Six Grab Sample
Locations During a Storm Event, June 30,1977, and the BOD of
Composite Samples Taken Throughout this Storm Event
(the predominant feature suspected of influencing BOD is also listed).
Predominant Feature of Watershed
Grab Samples:
Amish Farming
Amish Farming (Wertz Drain)
Conventional Farming
Urban (Dreisbach Drain)
Urban (Richelderfer Drain)
Confined Feeding Operation (Tile Drain)
Composite Samples:
Site 2 - Conventional Farming - No Urban Buildup
Site 6 - Amish Farming - Urban Buildup
BOD mg/l
12.0
16.0
6.6
14.0
16.0
480.0
6.3
9.3
Grab samples were taken on the three major drains of Black Creek prior to peak flows
on June 30 (Table 5). BOD concentrations were similar in all three samples ranging from
14 to 16 mg/l. Two of the samples were taken downstream from the town of Harlan and
the other from a predominantly Amish farming area. The urban area with its septic
effluent and the Amish area with a large number of unconfmed livestock appear to be the
factors that created higher BOD concentrations in stream flows (14-16 mg/l) compared to
runoff from conventional cropland (6.6 mg/l).
Composite samples collected from the Smith-Fry Drain (Site 2) and the Dreisbach
Drain (Site 6) also illustrate the effect of urban buildup and Amish farming practices on
BOD concentrations. The Smith-Fry watershed lacks any urban influence and the area is
farmed predominantly by conventional methods. The Dreisbach watershed contains the
town of Harlan and a large number of Amish farms. Composite BOD concentrations for
Sites 2 and 6 were 6.3 and 9.3 mg/l, respectively. BOD loadings for this storm were 364
and 239 kg at Sites 2 and 6, respectively. More rainfall and runoff on the Smith-Fry
watershed accounted for the greater loading at Site 2. Expressed on an areal basis, BOD
losses for this single storm were 40.9 kg/km2 for the Smith-Fry watershed and 32.5 kg/
km2 on the Dreisbach watershed.
920
Organic Pollution in an Agricultural Watershed
Fish Kill Caused by Organic Pollution
On September 29, 1977, several thousand gallons of manure slurry were accidentally
discharged into Black Creek when an animal waste holding lagoon was emptied directly
onto adjoining cropland. The slurry entered a subsurface tile network through broken
tile lines and/or surface inlets and was delivered to the stream with very little dilution
(Table 6). The impact at the outfall was devastating and low stream flows were inadequate to dilute the pollutant to nontoxic levels. m e material moved downstream as a
slug which could be visually detected. Three downstream samples had very high BOD
(130-300 mg/l) even prior to the arrival of the main slug of pollutant. Ammonia N concentrations were also greatly elevated (Table 6).
Fish mortality was severe in the entire 9 kilometers of stream below the spill. Mortality probably resulted from low oxygen levels and/or an ammonia toxicity. Detailed
notes on this fish kill have been reported elsewhere (Morrison, et al., 1977) but its occurrence is mentioned here to illustrate the pollution hazards of confined livestock feeding
operations. Accidental or intentional discharge of organic pollutants from animal waste
holding facilities can create gross organic pollution in streams when discharge is low and
potential damage is the greatest. Widespread organic pollution from other sources (septic
tanks and unconfined livestock) is greatest at high stream discharge when dilution reduces
the impact on aquatic life.
TABLE 6 . BOD and Ammonia N Concentrations of Grab Samples Taken on Black Creek
During a Major Fish Kill (September 28,1977) (one sample was taken just upstream from
the source of pollutant and four samples were taken at various distances downstream).
Sample
Location
BOD
mgD
Ammonia N
Upstream
Source (tile line)
Downstream 100 m
Downstream 580 m
Downstream 1720 m
Downstream 2440 m
2.1
28,000
7,200
130
2 20
3 00
1.2
2,400
600
11
18
20
mg/l
DISCUSSION
Water quality plans for rural areas must consider fecal contamination as a human health
hazard and organic pollution in terms of its impact on the aquatic life of the stream. The
concerns for human health standards are obviously of primary importance. Current
federal guidelines dictate 200 FC/100 ml for whole body contact recreation, 1000 FC/
100 ml for other water recreation activities, and 2000 FC/lOO ml and 10,000 TC/lOO ml
for water supplies (Fed. Wat. PCA 1968). Potential bacterial contamination exists
wherever septic tanks are constructed on unsuitable soils (Reneau, et al., 1968). Pollution from septic tanks is a major problem in the Black Creek watershed and its effects
were detected at both low and high stream discharge. Contamination during low flow was
severe at sewage outfalls and persisted throughout downstream areas at 500 FC/lOO ml.
92 1
Dudley and Karr
Storm runoff increased downstream fecal pollution an order of magnitude. Scouring and
transport of fecally contaminated sediment is suspected of causing this increase. In a
study of salmonellae and fecal coliforms in bottom sediments, VanDonsel and Geldreich
(1971) noted that movement of fecally contaminated sediments poses new water quality
problems which must be considered. Thus, small unsewered communities create potential
human health hazards within the immediate drainage at low flows and may substantially
contaminate water for downstream uses during high flows.
When organic pollution is a major influence on the aquatic life of a stream it becomes
important to determine the source and nature of the pollutant. On large rivers the
sources are generally point discharges that are easy to identify, regulate, and control
effectively. However, in smaller agricultural watersheds the problem becomes more complex due to the many sources of organic pollutants and their relationship to storm runoff
events. Our findings suggest the various sources of organic pollutants in an agricultural
watershed have differing impacts on the aquatic environment.
At low flow, septic tanks continually discharge organic pollutants into streams. Because there is little dilution of the pollutant in the vicinity of the outfall, fish cannot
tolerate these stream sections and the flora and invertebrate fauna are typical of grossly
polluted waters. Further downstream the organic loading from septic tank sources adds
to the organic matter of bottom sediments and in many areas this creates anaerobic
sediments (pers. observ.). In this manner septic tank pollution affects the aquatic invertebrate community.
Typically organic pollution from other sources occurs only during storm runoff events.
Decreasing FC/FS ratios during storm water runoff indicates substantial livestock sources
of fecal pollution in the Black Creek watershed. Circumstantial evidence indicates that
farms with unconfined livestock (pasture and barnlot) contribute more fecal pollution
than confined livestock operations. Feachem (1974) observed a similar increase in the
fecal contamination of storm water from unconfined livestock sources. Pollution from
septic tank sources increases at high stream discharge because of the scouring and transport of fecally contaminated sediments. BOD samples taken during a storm event indicate high levels of organic pollution (15 mg BODlml). In a small drainage these high
concentrations are maintained only for short periods of time and damage to aquatic life
is probably minimal. However, total loading of organic pollutants from an agricultural
watershed to a receiving river or lake increases significantly during storm events. For the
Black Creek drainage an average BOD loading of 36.7 kg/km2 occurred during a single
storm. Two agricultural areas in New Jersey were found to export up to 152 and 16.8
kg/day/km2 during high runoff periods (Yu, et al., 1975). It is clear that nonpoint water
quality plans must consider the impact of agricultural sources of BOD on receiving rivers
and lakes.
A fish kill caused by a discharge of liquid manure illustrates a severe pollution hazard.
Confined livestock operations equipped with waste holding facilities are designed to prevent organic pollution of nearby streams. The vast majority of these systems accomplish
this goal but modem livestock operations still represent a potential for gross organic pollution simply because of the large volume of wastes involved. Proper management of
waste holding facilities is essential to avoid the consequences of accidental or intentional
discharges of fecal material into streams. A few moments of carelessness can negate the
value of several years of pollution control at a multitude of other sources.
922
Organic Pollution in 2n Agricultural Watershed
ACKNOWLEDGMENTS
Thanks to the Allen County Board of Health, Fort Wayne, and Pollution Control Systems, Lnc.,
Laotto, Indiana, for conducting laboratory studies. Isaac Schlosser commented on an earlier draft of
this paper. This study was supported as a part of the U.S. Environmental Protection Agency
PL 92-500, Section 108(a) demonstration project to Allen County Soil and Water Conservation
District.
LITERATURE CITED
American Public Health Association, 1971. Standard Methods for the Examination of Water and
Wastewater. Washington, D.C. (13th Edition).
Burwell, R. E., G. E. Schuman, R. F. Piest, R. G. Spomer, and T. M. McCalla, 1974. Quality of Water
Discharged from Two Agricultural Watersheds in Southwestern Iowa. Water Resour. Res.
10:359-365.
Faust, M. A., 1976. Coliform Bacteria From Diffuse Sources as a Factor in Estuarine Pollution.
Water Res. 10:619627.
Feachem, R., 1974. Fecal Coliforms and Fecal Streptococci in Streams in the New Guinea Highlands.
Water Res. 8:367-374.
Federal Water Pollution Control Administration, 1968. A Report of the Committee on Water Quality
Criteria. US. Dept. of Interior, Washington, D.C.
Geldreich, E. E. and B. A. Kenner, 1969. Concepts of Fecal Streptococci in Stream Pollution.
J. Water Pollut. Contr. Fed. 41:R336-352.
Geldreich, E. E., 1970. Applying Bacteriological Parameters to Recreational Water Quality. J. Amer.
Waterworks Assn. 62: 113-120.
Harms, L. L., P. Middaugh, J. N. Dornbush, and J. R. Andersen, 1975. Agricultural Runoff Pollutes
Surface Waters, Part 1. Water Sewage Works 122: 84-85.
Hynes, H. B. N., 1960. The Biology of Polluted Waters. Univ. Toronto Press, Toronto.
Janzen, J. J., A. B. Bodine, and L. 1. Luszcz, 1974. A Survey of Effects of Animal Wastes on Stream
Pollution from Selected Dairy Farms. J. Dairy Sci. 57:260-263.
Morrison, J., ef al., 1977. Environmental Impact of Land Use on Water Quality: Final Report of the
Black Creek Project. USEPA, Chicago, Illinois (4 Vols.).
Reneau, R. B., Jr., J. H. Elder, Jr., D. E. Pettry, and C. W. Weston, 1975. Influence of Soils on
Bacterial Contamination of a Watershed from Septic Sources. J. Environ. Qual. 4:249-252.
Smith, J. H. and C. L. Douglas, 1973. Microbiological Quality of Surface Drainage Water from Three
Small Irrigated Watersheds in Southern Idaho. J. Environ. Qual. 2:llO-112.
Van Donsel, D. J. and E. E. Geldreich, 1971. Relationships of Salmonellae to Fecal Coliforms in
Bottom Sediments. Water Res. 5:1079-1087.
Weidner, R. B., A. G . Christianson, S. R. Weibel, and G. G. Robeck, 1969. Rural Runoff as a Factor
in Stream Pollution. J. Water Pollut. Contr. Fed. 41 :377-284.
White, R. K., 1972. Stream Pollution from Cattle Barnlot (feedlot) Runoff. Ohio Water Resources
Center, Project Completion Report No. 393X. 33 pp. (Also National Technical Information Service - PB-220-010.)
Yu, S. L., W. Whipple, Jr., and J. V. Hunter, 1975. Assessing Unrecorded Organic Pollution from
Agricultural, Urban, and Wooded Lands. Water Res. 9:849-852.
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