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1
IPA Region VIII LIBRARY^
^ Denver, Colorado
S&A/TSB-5
BACTERIOLOGICAL SURVEY OF THE
CACHE LA POUDRE RIVER
near Greeley, Colorado
April, 1972
TECHNICAL SUPPORT BRANCH
SURVEILLANCE AND ANALYSIS DIVISION
U, S, ENVIRONMENTAL PROTECTION AGENCY
REGION VIII
November, 1972

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TABLE OF CONTENTS
Page
INTRODUCTION	1
STUDY AREA DESCRIPTION	1
APPLICABLE WATER QUALITY STANDARDS	3
SURVEY PROCEDURES	3
RESULTS AND DISCUSSION	5
General	5
Rainfall Effects	5
Drainage Ditches	7
Sewage Treatment Plants	7
Comparison With Earlier Surveys	7
SUMMARY	9
REFERENCES	10
APPENDIX - DATA SUMMARIES	11
i

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LIST OF TABLES
Page
1)	Sample Point Locations	4
2)	Summary of Total and Fecal Coliform Counts	6
3)	Log Mean Total and Fecal Coliform Counts	8
for Several Different Surveys on the Cache
La Poudre River
LIST OF FIGURES
1) Map of Survey Area	o
ii

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INTRODUCTION
Two brief microbiological studies of the Cache La Poudre
River in the Greeley, Colorado, area were conducted during
April, 1972, to:
(1)	Identify the source(s) of bacterial pollution in the
reach bracketed by the foot-bridge crossing at Island
Grove Park and the low head dam at 2nd Avenue. (This
reach is upstream of the effluents from the Greeley
wastewater treatment plant and the Great Western sugar
beet factory)
(2)	Develop some insight to the relative impact of storm
runoff on the bacteriological quality of the river in
the Greeley area.
Although bacteriological degradation of the river in the
Island Grove Park - 2nd Avenue reach was identified in EPA
studies conducted during the last half of 1971, the source
or sources were not identified since these studies were de-
signed to assess the effect of Great Western's sugar factory
effluent on water quality.
STUDY AREA DESCRIPTION
The Cache La Poudre River flows from west to east along the
north edge of Greeley, Colorado, and is bordered by agricultural
and marsh lands, gravel pits, cattle feed lots, junk yards, a
meat packing plant, a sugar beet refinery, a livestock truck-
washing facility, a municipal sewage treatment facility, a city
park, and residential area. All this development is located in
the river flood plain and provides the potential for significant
bacteriological pollution during periods of storm runoff.
In contrast to the large number of potential sources during storm
runoff, there are only a limited number of direct discharges to
the Cache La Pourdre River in the Greeley area. The effluent from
the Greeley wastewater treatment plant enters the river downstream
from the 2nd Avenue Dam. As previously reported (Ref.2) the treat-
ment facility is severely overloaded by packing house wastes re-
sulting in heavy bacteriological and organic loadings on the river.
Effluent from the Eaton sewage treatment plant (oxidation ditch
secondary treatment) flows down Eaton draw and enters the river
at a point approximately 1.5 miles upstream from 2nd Avenue. The
operation of the Great Western sugar factory is seasonal occurring
during the winter months. The factory was not in operation during
the April studies.
1

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N
A
MONFORT
Figure 1
Map of Survey Area

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With the exception of the wastewater treatment plant effluents
the only other observed discharges were from a gravel pit
(RM8.2), the Monfort meat packing plant (RM7.0), and several
small drainage ditches containing spring water and irrigation
return water. Figure 1 shows the locations of the various dis-
charges .
APPLICABLE WATER QUALITY STANDARDS
During 1971, the State of Colorado adopted the following coli-
form standards for the Cache La Pourdre River in the Greeley
area: (Ref.3)
(1)	Upstream from the 2nd Avenue Bridge - the highest classi-
fication is a warm water fishery (Class B2). Fecal con-
forms must not exceed a log-mean of 1000 per 100 ml or
2000 per 100 ml in more than 10% of the samples collected
in any 30-day period.
(2)	Downstream from the 2nd Avenue Bridge to the mouth - Classi-
fication as industrial and irrigational waters (Classes C
and D^) with no coliform limits.
SURVEY PROCEDURES
The selection of sampling periods was based on the desirability
of making bacteriological measurements during periods of normal
and storm runoff conditions. During normal flow conditions a
bacteriological baseline can be established for use as a reference
for evaluation of data collected during times of increased bac-
teriological loading; i.e., storm runoff.
The time period of April 18-21, 1972, was selected as a suitable
interval for the collection of baseline data in anticipation of
significant storm activity within a subsequent period of 2 to 3
weeks. Precipitation (about % inch rainfall) did occur on April 26
and sampling was undertaken on April 27 and 28. Although the
rainfall was associated with a one foot rise in the Cache La Poudre
River, there did not appear to be any significant overland runoff
in the Greeley area. This being the case, the increase in flow
was most likely due to additional rainfall over upstream areas.
Sampling was conducted at 7 stations on the Cache La Poudre River
covering a 13 mile reach (river miles 2.9 to 15.7). In addition,
samples were collected from Eaton draw, two drainage ditchs, and
the Greeley wastewater treatment plant. Sample station descriptions
3

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To:
ENVIRONMENTAL PROTECTION AGENCY	j^X> S
\-itf ty.v/
Date: January 24 , 1S73
Reply to
Attn of: AtaVO
Review of S and A report entitled "Bacteriological Survey of the
Subject: r2C^e i_a Poudre River near Greeley* Colorado - April, 1972"
fv ¦
Charles W. Murray, Jr. _yy
Thru: Wi 11 i atr: H. Hormbery
-r
At Mr. Homiberg's requeitN, I nave briefly reviewed the subject
report and have the following cormnents:
'!. One of the objectives of the study was to identify pollution
in the reach from the fool-bridge at Island Grove Park to the low
head dam at Second Avenue. Since there was apparently no sampling
station at Second Avenue, it might help the report if it were explained
tr.at there are no potential pollution sources of any significance in
the reach from the 6th Avenue Bridge down to the low head dam at
Second Avenue.
2. It would seem to me that the .report should indicate that
the 2nd objective of the study as listed on page 1 could not be
accomplished due to the absence of adequate rainfall during th.e study
period lo produce any significant runoff in the Greeley area. While
I/? inrh nf rniflfaii di^ occur. the rcoorf r.t"..",.tt." "ac" ' that
"Although t'ne rainfall was associated with a one foot rise in the Cache
La Poudre Ri-ver, there did not appear to be any significant overland
runoff- in the -Greeley area.-"
I would like to make it clear that I am not criticizing the S and A
Division due to the fact that their study did not cover a period of
significant runoff. From my experience in Kansas, I know how difficult
it is to get water pollution evidence on feed lot runoff. Such studies
almost have to be conducted during and immediately following a runoff
situation, It is not easy to get prompt notification of the runoff
condition, get a crew together, and implement a sampling program within
the time available.
I am concerned, however, that unless there is a disclaimer in the repori
regarding the capability of adequately developing an insight as a result
of the. study into the relative impact of storm runoff, that, it might tend
to white-wash the Menfort feed lots as a significant pollution source
under runoff conditions if the feed lots are, in fact, a significant

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pollution source. I obviously do not know for sure if they	are
or notj but I do not think that the study provides evidence	that
the feed lots might not severely pollute the river at times	of
storm runoff in the feed lot area.
Stanley M. Smith
Municipal Waste Water Branch

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TAELE 1
Sample Point Locations
Station
il
River Mile
Location
Sampling Point
CLP-2
CLP-4
CLP-6
DD-7
CLP-7
ED-8
CLP-10
STP-14
CLP-16
CLP-18
DD-17
ED-1
ED-2
15.7
9 A
7.8
7.4
7.1
6.9
6.3
5.3
5.2
2.9
2.9
CLP River
U miles west of Mumper Corner
CLP River
Bridge at Spanish Colony
CLP River
Island Grove Park
Upstream side of County Road Eridge
Upstream side of Bridge
Upstream side of Bridge
Drainage Ditch Located	North Bank of River
Between 8th and 11th Ave. Bridges
CLP River
Eighth Avenue Bridge
Culvert Near Mouth of
Eaton Draw
CLP River
6th Avenue Bridge
Greeley Sewage Treatment
Plant
CLP River
First Bridge Below Greeley
Sewage Plant Outfall
CLP River
Bridge South of Weld County
Airport
Downstream Side of Bridge
Downstream End of Culvert
Upstream Side of Bridge
Chlorination Easin Effluent Point
Upstream Side of Bridge
About 200 yds upstream of Bridge on north
bank
Drainage Ditch South of Weld Upstream end of culvert
County Airport
Eaton, Colorado Sewage
Treatment Plant
Eaton Draw About 3 miles
Below Eaton Outfall
Effluent Pipe
Upstream End of Culvert Under County Road

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are presented in Table 1 and depicted in Figure 1. At each station,
surface grab samples were collected using sterile 250 ml wide-mouth
bottles. Field measurements included temperature, stream depth,
visual assessment of the water condition (clear, turbid, etc.) and,
in the case of the wastewater treatment plant effluent, the chlorine
residual. The residual chlorine values are shown in Table 5 in the
Appendix.
All samples were analyzed for total and fecal coliforms by the milli-
pore filter method. Selected samples were also analyzed for fecal
streptococcus. Analyses were conducted in accordance with the 13th
Edition of "Standard Methods for the Examination of Water and Waste-
water." (Note: The Biology Department, University of Northern
Colorado, graciously donated laboratory space to EPA for the conduct
of bacteriological analyses)
RESULTS AND DISCUSSION
General
A total of 72 water samples were collected from the Cacha La Poudre
River and its tributaries during the two studies. Analysis of each
sample for total and fecal coliforms yielded results which are sum-
marized in Table 2. Colorado water quality standards for the Cache
La Poudre River upstream from the 2nd Avenue Bridge require that
fecal coliform bacteria not exceed a log-mean value of 1000 per 100
mis. In this study, 30 samples were collected from 5 stations above
the 2nd Avenue Bridge and only 3 (10%) of these samples exceeded
1000 fecal coliforms per 100 ml. The average log-mean value for the
5 river stations upstream from the 2nd Avenue Bridge was 212 fecal
coliforms per 100 ml. The state standard was, therefore, not violated.
Rainfall Effects
On April 26, 1972, the Greeley area received about h inch of rainfall
with an undetermined amount of rainfall occurring further upstream.
The following day the river was higher by about one foot, and, as
shown in Tables 1 and 2 in the Appendix, there was an associated in-
crease (by a factor of about 5) in total and fecal coliform concentra-
tions at each station. Due to the dry soil conditions before the rain
in the Greeley area, no significant surface runoff was observed. The
increase in total and fecal coliforms was likely caused by bacteria
washed from the river banks in adjacent pastureland and feedlot areas
and by bacteria brought downriver from unknown sources by the increased
river flow.
When the river returned to its original depth on April 28, the total
and fecal coliform concentrations likewise returned to their original
levels.
5

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TABLE 2
Summary of Total and Fecal Coliform Counts

Total
Coliforras/100ml

Fecal Coliforms/lOOml
s£a-
Location Samples Maximum
Minimum
Log-Mean
value
Samples
If
Maximum
Minimum
Loe-Mean
Value
CLP-2
CLP-River 4 mi. west
of Mumper Corner at
County Road Bridge
6
7100
500
2024
6
1300
150
317
CLP-4
CLP River
Bridge at Spanish Col.
6
3300
260
934
6
610
20
145
CLP-6
CLP River 6
Footbridge Is.Grove Pk.
3600
190
466
6
1200
50
188
DP-7
Drainage Ditch in No.
Bank between 8 & 11th
Avenue Bridges
6
9200
720
2777
6
6400
100
1281
CLP-7
CLP River
Eight Avenue Bridge
6
2900
210
613
6
1400
50
215
ED-1
Eaton, Cole.Sewage
Treatment Plant Effl.
5
5000
1700
3283
5
1100
180
579
ED-2
Eaton Draw about 3mi. 1 1100
below Eaton Sewage Outfall
1100
1100
1
40
40
40
ED-8
Culvert near Mouth of
Eaton Draw
6
35000
200
3724
6
1800
60
469
CLP-10
CLP River
6th Avenue Bridge
6
48000
180
1002
6
1000
110
195
STP-14
Greeley Sewage Treat.
Plant Effluent
6
6700000
7600
888500
6
740000
100
8880
CLP-16
CLP River g
First Bridge below
Greeley Sewage Outfall
990000
1100
30550
6
180000
40
3664
DD-17
\
Drainage Ditch
South of Weld County
Airport
6
5000
400
1341
6
520
80
171
CLP-18
CLP River
Upstream of Bridge
South of Weld County
Airport
6
460000
500
15375
6
34000
340
3934

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Drainage Ditches
The concentration of total coliforms in the river increased by more
than 100% (as the log-mean measurement) between the Island Grove Park
footbridge and the 6th Avenue Bridge. Fecal coliforms increased by
only 3*5% in this same stretch of river. The increase in total coli-
forms was due primarily to the two tributary streams entering the
river on either side of the Monfort Packing Plant (DD-7 and ED-8).
Eaton Draw (ED-8) contains the sewage effluent from Eaton, Colorado,
plus additional irrigation return water. The drainage ditch (DD-7)
flows through a marshy, junk-littered area and then into the river.
Sewage Treatment Plants
It can easily be seen from Table 2 that the Greeley sewage treatment
plant generally produces a gross bacterial overload on the Cache La
Poudre River. This contamination is due primarily to the extremely
overloaded condition of the sewage treatment plant caused by meat
packing wastes from the Monfort Packing Plant. Although heavy chlorine
dosages were commonly employed at the sewage treatment plant, adequate
disinfection was often not accomplished. For example, Table 2 in the
Appendix shows that fecal coliform counts were above 450,000 per 100
ml on 3 out of 6 days during the study. On the remaining 3 days dis-
infection reduced the fecal coliform concentration to 200 per 100 mis
or less. It is clear'that the Cache La Poudre River would benefit
greatly from more reliable disinfection at the Greeley sewage treat-
ment plant.
This study also shows that the Eaton sewage treatment plant (oxida-
tion ditch secondary treatment) has generally effective chlorination.
Results show a residual log-mean fecal coliform value of only 579 per
100 mis, which is less than the warm water fishery standard adopted
by the State of Colorado for the reach of the Cache La Poudre River
affected by this discharge.
Comparison With Earlier Surveys
As a matter of interest the results of total and fecal coliform
analyses from three previous surveys of the Cache La Poudre River
are presented with similar data from this survey in Table 3. The
surveys of September and December, 1971 (Ref. l) were rnnrinrt-e/i
jointly by the National Field Investigations Center ! Denver and
Region VIII-EPA, whereas this survey and the November, 1971, survey (Ref.2)
were conducted by Region VIII only. Table 3 shows a significant varia-
tion for the September and November surveys while there is fairly close
agreement between the April and December survey results. There is not
enough data to determine the exact causes for similarity or disagree-
ment in survey results except for the November survey. During that
survey, the Great Western sugar beet refinery was in full operation
and undoudtedly contributed to the coliform increase in the lower
stream reach.
7

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TABLE 3
Log Mean Total and Fecal Coliform Counts for Several Different
Surveys on the Cache La Poudre River


Log-Mean Total Coliforms/lOOml

Log-Mean Fecal Coliforms/lOOml
Sta.
#
Location
*Sept. **Nov. *Dec.6,7
13-15/71 16-18/71 13-15/71
Apr.18-21
27-28/72
*Sept. **Nov. *Dec.6,7 Apr.18-21
13-15/71 16-18/71 13-15/71 27-28/72
CLP River
CLP-4 Bridge at Spanish Colony 9600
CLP River
CLP-6 Footbridge at Island
Grove Park
960
934 640
466
300
145
188
oo
CLP River
CLP-7 8th Ave. Bridge
ED-8
Culvert Near Mouth
of Eaton Draw
2298
613
3724
212
500
215
469
CLP River
CLP-10 6th Ave. Bridge	20000	7266
Greeley Sewage Treatment
STP-14 Plant Effluent	4879000
1900	1002 3200
888500
2569
22000
220
195
8880
CLP River
CLP-16 First Bridge Below	38000
Greeley Sewage Outfall
CLP River
CLP-18 Upstream of Bridge South
of Weld County Airport
429400 47000 30550 2500 226500
3400
525600
15375
134300
3664
3934
* Values from National Field Investigations Center Report
** Region VIII EPA Report ^ - Laboratory Analysis by Colorado State Health Dept.

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SUMMARY
The findings which relate to the occurance and distribution of total
and fecal coliforms in the Cache La Poudre River are the following:
1.	Fecal coliform standards for that portion of the river
classified as a warm water fishery were not exceeded at
any sample location.
2.	The primary sources of bacteriological pollution between
the Island Grove Park (CLP-6) and Second Avenue are:
a)	A drainage ditch flowing through a junk
yard near the north river bank at Station
DD-7.
b)	Eaton Draw which carries treated municipal
sewage from Eaton, Colorado, and irrigation
runoff from nearby agricultural lands.
3.	Total and fecax coli:com densities increased significantly
(by a factor of about 5) after a rainfall of inch in
the Greeley area and an associated river rise of about one
foot. This increase was likely caused by bacteria washed
from the stream banks in adjacent pastureland and feedlot
areas and by bacteria brought downriver from unknown sources
by the increased river flow. The same pattern of decreased
water quality during runoff periods can be expected in the
future.
A. The Greeley sewage treatment plant often does not provide
adequate disinfection to the discharged effluent. Fecal
coliforms varied from >100 to 740,000 per 100 ml. The quality
of this effluent should improve significantly with the construc-
tion of an alternate sewage treatment facility for the Monfort
Packing Plant wastes.
5.	Total coliform densities increased by more than 100% primarily
as a result of the two tributary streams on either side of
the Monfort Packing Plant (RM 7.A to 6.9). These two flows
are the sources for the high coliform counts found during
the November, 1971 survey in the stream reach upstream from
the sewage plant and sugar beet refinery discharges.
6.	Data from this survey agree closely with results from the
December, 1971 survey but differ markedly from the September
and November, 1971 survey results. The explanation for the
high coliform concentrations in November is that the Great
Western sugar beet refinery was in full operation and contri-
buted significant wasteloads at that time.
9

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REFERENCES
Report on Effects of Waste Discharges on Water Qualtiy
of the Cache La Poudre and South Platte Rivers - Greeley
Area, National Field Investigations Center - Denver and
Region VIII, Denver, Colorado, February, 1972.
Summary of a Water Quality Survey - Greeley, Colorado,
November 16-19, 1971, Region VIII. EPA. Denver, Colorado,
July, 1972.
Water Quality Standards and Stream Classification, Water
Pollution Control Commission, Colorado Department of Health,
1971.
10

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APPENDIX
Data Summaries
11

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TABLE 1
Total Coliforms at all Stations
Counts/100ml
Station
#
River
" Mile
4/18 4/19 4/20
4/21 4/27 4/28
CLP-2
CLP-4
CLP-6
DD-7
CLP-7
ED-8
CLP-10
STP-14
CLP-16
CLP-18
DD-17
ED-1
ED-2
15.7
9.4
7.8
7.4
7.1
6.9
6.3
5.3
5.2
2.9
2.9
500
420
320
9200
260
12000
580
6700000
990000
13000
800
600
350
270
4000
430
3900
550
480000
1700
500
5000
3400
3900
3300
580
1600
340
2200
400
720000
3800
8000
400
5000
1100
2300	7100
260	2500
190	3600
2300	4700
210	2900
200	35000
180	48000
7600	4300000
1100	680000
4600	460000
450	4500
1700	4400
3600
2100
300
720
2300
3700
920
6500000
170000
120000
1800
3000
12

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TABLE 2
Fecal Coliforms at all Stations
Counts/100ml
Station
#
River
Mile
4/18 4/19 4/20
4/21 4/27
4/28
CLP-2
CLP-4
CLP-6
DD-7
CLP-7
ED-8
CLP-10
STP-14
CLP-16
CLP-18
DD-17
ED-1
ED-2
15.7
9.4
7.8
7.4
7.1
6.9
6.3
5.3
5.2
2.9
2.9
370
150
50
6400
140
1800
140
740000
180000
6500
120
150
220
75
3200
240
500
230
>100
100
340
250
1000
440
330
220
1400
140
1100
130
100
300
830
90
330
40
160
70
60
100
50
60
110
200
40
2200
80
1100
1300
610
1200
2200
1400
300
1000
460000
80000
27000
520
180
200
20
120
700
300
600
120
720000
140000
34000
220
1000
13

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4/28
54
54
50
54
49
48
49
64
48
47
44
53
TABLE 3
Water Temperatures at all Stations
of
River	4/18 4/19 4/20 4/21 4/27
Mile
15.7
51
47
44
52
42
9.4
52
48
48
54
42
7.8
53
48
49
52
42
7.4
53
48
50
57
42
7.1
53
47
49
51
42
6.9
53
46
52
52
42
6.3
55
49
53
52
44
5.3
62
58
64
63
62
5.2
55
50
56
52
46
2.9
56
50
54
50
46
2.9
55
50
50
47
43
-
-
54
56
55
50
_
_
__
58

_

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TABLE 4
Time of Sample Collection
Station	River	4/18	4/19	4/20	4/21	4/27	4/28
#	Mile	
CLP-2	15.7	0915	1210	0845	1100	0930	1028
CLP-4	9.4	1000	1135	0910	1035	0945	1013
CLP-6	7.8	1015	1100	0940	1015	1000	1000
Dd-7	7.4	1100	1025	0955	1000	1006	0950
CLP-7	7.1	1130	0950	1005	0950	1020	0938
ED-8	6.9	1145	0930	1045	0935	1050	0902
CLP-10	6.3	1215	0920	1100	0925	1055	0855
STP-14	5.3	1300	0900	1120	0910	1130 0840
CLP-16	5.2	1235	0840	1130	0855	1140 0830
CLP-18	2.9	1330	0750	1145	0835	1150	0815
DD-17	2.9	1345	0810	1200	0835	1155	0810
ED-1	- -	1505	1400	1210	1030 0920
ED-2	- -	1330
15

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TABLE 5
Chlorine Residual
PPM
Station	River	4/18 4/19 4/20 4/21 4/27 4/28
//	Mile	
CLP-2	15.7
CLP-4	9.4	______
CLP-6	7.8
Dd-7	7.4
CLP-7	7.1
ED-8	6.9
CLP-10	6.3	-
STP-14	5.3	0 0.5 0.5 0.5 0	0
CLP-16	5.2	0 0 0.1 0.1 -	0
CLP-18	2.9	______
DD-17	2.9	______
ED-1	-	- 0.1 0.1 0.25 0.5 0.5
ED-2	-	- -
16

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