ENVIRONMENTAL PROTECTION AGENCY
ROCKY MOUNTAIN-PRAIRIE REGION
FY 74 SEGMENT PLAN
UPPER SOUTH PLATTE RIVER BASIN (COLORADO)
(Water Quality Limited Segment)
-------
'^3 si
aitH
FY 74 Segment Plan
for the
Upper South Platte River Basin in Colorado
(Water Quality Limited)
br
80C-LPA R~
,9f !8lh S. , Suite 500
2SS_CO 80202.4
ary
John A. Green
Regional Administrator
Environmental Protection Agency
Region VIII, Denver, Colorado
September, 1973
-------
SUMMARY
In summary, to ensure the protection of water quality in the Upper South Platte Basin and that water quality
standards are not violated, permits in the segment should be written as follows:
Facility
Fairplay
G & C Camp
Geneva Ski Basin
Santa Maria
Bailey San. Dist.
Perry Park San. Dist.
Castle Rock San. Dist.
Silver Hts. San. Dist.
Louviers, 3vD.
Dupont Co.
(1) Cooling water discharge - 001
Martin Marrietta Co.
Denver Water Board, Kassler Plant
Permit Conditions
Immedi ate
Present quality but to meet state
disinfection standards of 5000
fecal coliform/100ml
B0D5 = 10mg/l NH3-n = 1.0mg/l
NO2-N + NOg-N - 5 mg/1 SS - 30mg/l
BODg - 30 mg/1
Present Quality
By 1975
B0D5 - 25mg/l
SS - 25mg/l
By Jan. 1975
BOD5 = 10mg/l
NH3-N - 1.0mg/l
N0,-N + NO^-N -
5.0 mg/1 J
TSS - 20 mg/1
by Jan. 1974
B0Dr - 25 mg/1
TSS - 5 mg/1 by
PO4-P - 5 mg/1
by June 1974
BPT
By 1977
BODr - 20mg/l
SS - 20mg/l
Fecal coliform
200/100ml
By June 1977
BOD5 = 10mg/l
NH3-N - 1.0mg/l
N09-N + N0o-N -
5.6 mg/1
S.S. - 5.0 mg/1
by June 1977
BODc - 20 mg/1
TSS - 20 mg/1
PO4-P -see page 18
by June 1977
BPT
-------
Table of Contents
I. Introduction.
II. Basin Description.
a. S. Platte above Waterton
b. S. Platte below Waterton
c. Plum Creek
d. Line diagram of segment & point sources
III. Stream Standards and Uses.
a. Present
b. Proposed
IV. Assessment of Present Water Quality and Waste Discharges in Segment.
a. S. Platte above Waterton
b. S. Platte below Waterton
c. Plum Creek
V. Proposed Water Resource Projects and Future Dischargers Affecting
Water Quality in Segment.
VI. Effluent Standards.
a. Federal
b. State
c. Local
VII. Maximum Allowable Loads.
a. Middle Fork
b. North Fork
c. Plum Creek
d. Below Waterton
VIII. Chatfield Dam Nutrient Analysis
IX. Basin Strategy and Permit Priorities
Schedule of dischargers, needs and compliance dates.
X. Construction Grant Funding Needs.
-------
-------
WATER QUALITY LIMITED SEGMENT WITil ADEQUATE DATA
STATE: Colorado
BASIN: S. Platte River
SEGMENT: . S. Platte-Source to Chatfield Dam Outlet & Tributaries
INDUSTRIAL
Major
1. E. I. Dupont #270
2. Martin Marietta #460
Mi nor
1. Denver WTP (Kassler) #724
2. Peter Kiewit & Sons #687
MUNICIPAL.
Major
None
Minor
1. Bailey
2. Castle Rock
3. Fairplay .
4. Louviers
5. Perry Park
6. Silver Heights
7. G & C Camp
8. Geneva Ski Basin
9. Santa Maria
-------
fan ** play
Res
O
f "j Eleven
? / «*\\e.
V ees.
fP) CKsesar*©.*
W Woke
R.fA. 3S2
Colo U)$S4rodt\tt*v
•VioAtr-Vow fc..«\
W.S
a*tl«- R«dt
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-o •
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CWoc\-fie\d Davr» (ft.in.335^
Co\o ^5 ^VcwKor*
-------
I. Introduction - The State of Colorado has designated the South Platte River
and all tributaries above the outlet of Chatfield Dam as water quality
limited. The State has applied this water quality limited designation be-
cause of the present generally high water quality and because of projected
increasing recreational uses of these water. This segment plan has found
that this is true for the segment.
II. Basin Description - The segment can be physically divided into three reaches
because of the differences in problems and topography. The reaches used in
this water quality limited segment plan are:
a. The S. Platte and Tributaries above Waterton.
b. The S. Platte below Waterton (from Waterton to the Chatfield
Dam Outlet).
c. Plum Creek.
a. The South Platte and Tributaries above Waterton - The sources of the South
Platte and tributaries are on the eastern side of the Continental Divide and
flow through South Park before reaching the Front Range. This headwater
area is sparsely settled with nearly all of the land in the San Isabel and
Pike National Forests.
The South Platte and tributaries after leaving the Divide, except for
the North Fork, flow through South Park, which is a high semi-arid plain.
This area has a small population increase during the summer tourist season.
South Park is privately owned land with grazing on irrigated land its major
economic activity.
At the present time there are few second home subdivisions in this area
but at the current rate of growth in. other Colorado areas, the State feels
this area could also experience such developmental pressures with the resul-
tant required services. The 1972-census for Park County which covers most
of this area showed a population of 1,849, with the largest community being
Fairplay, with a population of 400.
- 1 -
-------
From the South Park area, the South Platte and tributaries pass through
the Front Range where the streams are typical fast flowing mountain streams.
The North Fork of the South Platte flows southeast from the Divide and joins
the South Platte at the town of South Platte at R.M. 352. The entire drain-
age area of the South Platte above Waterton, with the exception of the South
Park area, lies within the Pike National Forest which has very limited amounts
of private land holdings. Most of this privately owned land is in the valleys
and is used primarily for summer homes and recreational activities. According
to the 1970 census, the population of this area, which includes parts of Park,
Teller, Douglas and Jefferson Counties, is less than 15,000 persons. The major
communities in this area are Bailey, Deckers and South Platte.
The City of Denver Water Board uses the waters originating in these streams
as a major source of water for the City and at present, the Denver Water Board
has four major water storage reservoirs on the South Platte: Eleven Mile Res-
ervoir, Tarryall Reservoir, Antero Reservoir and Cheesman Reservoir. The City
of Aurora also draws some of its municipal water supply from this segment of
the South Platte. The Denver Water Board and Aurora divert above Waterton at
R.M. 349.2 and R.M. 343.0.
The Northern Colorado Highline Canal also diverts water for irrigation use
from this reach with its diversion at R.M. 341.3.
The North Fork of the South Platte is used as an open conduit to carry
Denver Water Board transmountain diversion water from the Dillon Reservoir in
the Colorado River Basin to the intake at Waterton.
b. The South Platte below Waterton - The South Platte abruptly leaves the
foothills at Waterton emerging from South Platte Canyon onto the plains. At
Waterton and below there are diversions for muncipal and irrigation use, the
largest being for the City of Denver Water Board at R.M. 339.3.
- 2 -
-------
The City of Englewood uses South Platte water for part of their water
supply with the City's diversion in Littleton at R.M. 328.7, some 7 miles
below Chatfield Dam.
The character of the River here becomes typical of East Slope streams
entering the Plains, that is shallow with a sandy bottom flowing through land
that in the past was used for cattle grazing.
The Corps of Engineers is completing construction of the Chatfield Dam
and Reservoir, a flood control and recreation project on the South Platte River.
The Dam itself is located at river mile 335.2, 4.3 miles below Waterton. This
Dam and Reservoir were designed primarily to provide flood protection for the
Denver area but storage volume will be available for municipal and industrial
water supply storage at a future date through utilization of a higher operating
pool elevation.
The Corps has made recreational activities in the reservoir area a signifi-
cant part of the project. A total of 6,500 acres have been purchased for inclu-
sion in the Chatfield Dam Recreation area. State and Local officials believe
that this area will become another major recreational site for the Metro Denver
area such as Cherry Creek Reservoir is now. The Jefferson County area to the
north of the dam and reservoir has had rapid development in the past five years
as developers and builders take advantage of the close proximity of this recrea-
tional area and undeveloped land. The 1970 population of this area was 540. The
DRCOG estimate for 1985 for the Chatfield area is 9,500 persons, with an esti-
mated year 2000 population of 27,400. At the present time a 3,000 acre planned
community called Roxborough Park with a projected 1990 population of 5,000 to
10,000 persons is developing immediately south of Waterton in Douglas County.
Presently, the Martin Marietta Company facility near Waterton is the only sig-
nificantly developed area nearby with a-daily work force of 5,000 persons.
- 3 -
-------
c. Plum Creek - Plum Creek lies entirely within Douglas County bounded on
the south by Monument Hill with the Rampart Range on the west providing drain-
age for the western half of Douglas County. Qouglas County is presently ex-
periencing development pressures as the Denver Metropolitan area urban sprawl
spills over into Douglas County. The County had a 1970 population of 8,315
with the primary land usage being cattle grazing. The largest community at
present is Castle Rock, the County Seat, with a population of 1,600. Other
unincorporated areas of the County are growing at a faster rate and will probably
exceed Castle Rock's population by 1980, unless Castle Rock annexes and develops
presently open lands adjacent to the City. At present the County does not have
a land use plan but is in the process of developing one. From conversations
with the County Planner there were, as of 1972, platted lots sufficient to
sustain a population of 175,000. In the Plum Creek Drainage Basin there are
two large developments now underway or planned.
Perry Park is a 45,000 acre development in the southwest corner of Douglas
County being developed as a rural upper middle class community featuring central
water and sewer systems. At present, the population is less than 1,500 persons.
The other planned community is Castle Pines which is located 2-5 miles north
of Castle Rock. Development of its approximately 5,000 acres has not yet begun.
The County hopes to preserve its rural character by limiting development to
planned communities such as Roxborough Park, Perry Park and Castle Pines which
will be kept isolated from one another with land between these communities being
limited to 10-40 acre minimum lot sizes.
Plum Creek is typical of many Eastern Colorado High Plains streams in that
after the spring runoff the surface water flow in the stream is minimal, reaching
zero flow at times during July, August and September nearly every year. The al-
luvium of the CreeK is very closely tied into the surface stream flow. Plum Creek
- 4 -
-------
joins the South Platte at River Mile 335.5 in the new Chatfield Dam Reservoir.
The reservoir recreation land extends up Plum Creek for approximately two miles
and will be developed in the future for various recreational uses.
III. Stream Standards and Water Uses - The South Platte and tributaries from the
headwaters to Bowles Avenue in Littleton are presently classified as A, B-j, C, D-j
except for Plum Creek which is not classified. The current Colorado Stream
Standards Criteria and the proposed Colorado Stream Standards are attached in
Appendix A. The A, B-p C, D-j standard provides for protection of the water for
drinking water, cold water fisheries, irrigation and industrial use. The un-
classified status of Plum Creek only requires that wastewater dischargers to the
stream meet the basic discharge standards.
The South Platte and tributaries above Chatfield Dam, except for Plum Creek,
are well known trout fishing streams and receive a considerable amount of fishing
pressure. However, the primary usage of the streams is "for the storage and sup-
ply of public water supplies for the Denver Metropolitan Area with almost all sur-
face water rights in the basin owned by municipalities."^
The construction of Chatfield Dam and Reservoir will greatly increase the
recreational aspects of water use in the South Platte in the recreation area.
The EPA has recommended that the South Platte and tributaries above Littleton
be reclassified to include body contact recreation, B3. The Colorado Water Quality
Control Commission has scheduled public hearings in November on proposed reclassi-
fication of streams in Colorado and changes in the stream classification standards.
The State has proposed that the mainstem and all tributaries of the South Platte
above Exposition Avenue in Denver (which would include Plum Creek) be classified
as B]. This new classification classifies these waters as suitable for all pur-
poses except primary contact recreation such as swimming and water skiing, and
also provides for protection of the streams as cold water fisheries.
1 Page 2 Interim Basin Plan for Upper S. Platte Basin in Colorado, Colo. Water
Quality Control Division, July, 1971.
- 5 -
-------
Ol)OL).-V
38 25 00.0 105 13 00.0 4
SOUTH PLATTE AT SOUTH PLATTE
08 COLORADO .
MISSOURI RIVER.
SOUTH PLATTE
21COL001 77777777
0000
I a J ¦„ r. i ; j _ . ...
• • • • • • • • • • •
vt^TEP, NUMBER MF.AN ...VARIANCE-STAN DEV COEF VAR.STAND ER MAXIMUM MINIMUM BEG DATE END DATE.
r. ¦:r : l
WATER
TF.mP
FAHN
27
43.9629
123.038
11.0923
.252309
2. 13471
63.0000
32.0000
68/10/29
72/09/28
i" 0
TIJ3R
JKSN
JTU
.20 ..
11.5650 .
82.7213
9.09513
.786436
2.03373
36.5000
2. 10000
63/10/29
72/05/10
C *• - ' • :
OWJUCTVY
AT 25C
MICRCMHO
22
214.955
9321.51
96.5480
.449155
20.5841
470.000
75.0000
68/10/29
72/09/23
0 ~ -) 0
00
MG/L
10_. .
8.05999 .
2.13832
1.46230
. 165045
.462420
11.5000
7.50000
70/10/20
72/09/23
J' "• w ' 0
0 O D
5 DAY
MG/L
7
1.44286
.429522
.655379
.454223
.247710
2.20000
.500000
69/02/26
72/08/29
0 - 0 0
PH
SU
27
7,63703..
. 1 IS488_.
.339835 .
.044498.
.065401
8.60000
_7.20000
68/10/29
7?/n9/?ft
00505
RESIDUE
TOT VOL
MG/L
6
39.3333
5615.07
74.9337
1.90509
30.5916
192.000
3.00000
69/02/26
72/09/28
o 5 i 5
RESIO'JE '
DISS- 105
C MG/L
22
130.000
3312.00
57.5500
.442692
12.2697
.290.000
54.0000
68/10/29
72/09/28
A f 7 — r
V . w
^CS I I'JE
TOT NpLT
MG/L
6
20.3333
241.467
15.5392
.764223
6.34385
46.0000
3.00000
69/02/26
72/09/28
o v;5
i^lSIOUE
SETTLeLE.
ML/L
6
.116667
.001667 .
.040825
.349927
.016667
.200000
.100000
69/02/26
72/03/29
Ci f-1 j
TOTAL
MG/L
19
.068947
.005310
.072869
1.05688
.016717
.250000
.000000
63/10/29
72/05/10
1 s
?0 ? -
total
MG/L
19
.001053
.000004_
.001929._
1.83212
...000442.
006000
.000000
63/11/27
7?/nci/ l o
' 0 - 2 0
N03-N
total
MG/L
21
.190952
.086469
.294056
1.53995
.064168
1.00000
.000000
68/10/29
72/05/10
ice-50
T P04-
P04
MG/L
_ .20..
.167500
• 067440
.259693
1.55041
.058069
1.10000
.000000
68/10/29
72/05/10
0 0720
CYANIDE
CM
MG/L
9
.000000
.000000
.000000
.000000
.000000
.000000
69/05/26
72/09/23
oo°oo
TQT HARD
CAC03
MG/I
. 21
84.7619
1103.69 .
33.2219
.391943
.7.24961
162.000
.38.0000
68/10/29
72/06/23
o o ! n
CALCIUM
CACfi3
MG/L
21
54.5233
639.763
25,2935
.463899
5.51950
115.000
.19.0000
63/10/29
72/06/23
'
I'JM
CAC03
MG/t
21
7.42857...
10.7572
3.27981 ...
.441513
.715714
. 16.0000
..2.00000
63/10/29
7P/06/27
DC '> .-V
SO'lI'JS
NA.DISS
MG/L
21
13.9043
82.8907
9. 10443
.654771
1.98675
39.0000
1.00000
68/10/29
72/06/23
oc-: j:
SCOI(Jy ..
A0S3T20N
RATIO
21
.842355.
1.29957
1.13999
1.35253
..248765
5.60000
.000000
63/10/29
72/06/23
oo-'^o
chloride
Cl
MG/L
21
15.4286
148.957
12.2048
.791053
2.66331
58.0000
2.00000
68/10/29
72/06/23
,0-0.94 5
SULFATE
.. S04
MG/t
21 ..
30.6190 .
170.949
13.0747 .
.427013
2.85314
60 .0000
10.0000
68/10/29
72/06/23
00550
fluoride
F.DISS
MG/L
10
.850000
.373889
.611464
.719370
.193362
2.40000
.200000
69/05/26
72/09/23
o: c o
ARSENIC
AS.DISS
UG/L
11
..000000 ..
.000000
.000000 .
. .000000
.000000
.000000
63/10/29
72/09/23
0 i C ?0
BC^Orj
tj.orss
UG/L
13
24.4444
1579.09
39.737/
1.62563
9.36627
120.000
.000000
6H/12/11
G : C c5
CtD"!lUM _
CO.DISS
UG/L
13 ..
.000000
.000000
.000000
.000000
.000000
.000000
68/10/29
72/09/28
0 10 22
Ch^OXIUM
HEX —V AL
UG/L
10
.000000
.000000
.000000
.000000
.000000
.000000
69/05/26
72/09/28
0 i 0 A 0
C0?=ER _..
. CU-DISS.
UG/l
10 .
.000000.
.000000
.000000 ..
. .000000
.000000
.000000
69/05/26
72/09/28
01045
iron
TOTAL
UG/L
21
266.666
31083.4
176.305
.661144
38.4729
650.000
.000000
68/10/29
72/09/23
0 1049
LEAD .
pe.oiss
UG/l
10
..000000 _
..000000
.000000 .
..000000
... .000000.
.. .000000
69/05/26.
72/09/28
0 1 055
MANGNESE
UG/L
20
5.00000
236.642
15.3897
3.07793
3.44124
50.0000
.000000
68/ 10/29
72/09/28
o l r. f
moly
mo.tqt
UG/L
3
.000000 .
.000000
.000000
.000000
.000000
.000000
71/02/25
72/09/23
¦j 1 ; 7 5
SILVER
AG.DISS
UG/L
7
.000000
.000000
.000000
.000000
.000000
.000000
69/02/26.
71/02/25
0 10S0
2IVC
ZN.DISS .
UG/L
21
68.0952
36816.2
191.875
2.81775
41.8706
720.000
.000000
68/10/29
72/09/23
CI 145
SELENIUM
SE.DISS
UG/L
11
.000000
.000000
.000000
.000000
.000000
.000000
68/11/27
72/09/23-
0 150 1
alpha
TOTAL
PC/L
6
. 13.9000_.
186.912
13.6716
.983567
5.58140
. 41.0000
.5.60000
69/06/20
72/01/24
01502
alpha-t
ERROR
PC/L
6
6.06666
2.37873
1.54231
.254227
.629646
8.70000
4.00000
69/06/20
72/01/24
0 350 1
BETA
..TOTAL
PC/I
3
,3. 12000
23.3532
4.83251 ...
1.54888
2.79005
8.7000C
.300000
69/04/21
69/10/30
03502
BETA-T
ERROR
PC/L
3
2.95333
21.4405
4.63039
1.56785
2.67336
8.3000C
.260000
69/04/21
69/10/30
-------
Table 1
INDEX 1021500
* L E S 1149.40 ¦
f- ?•'' -¦ - T P. _
3150 5 TOT "COLI •
31615 FEC COL I
36260 MBAS
71900 MERCURY
OOOOt-'S
38 25 00.0 105 13 00.0 4
SOUTH PLATTE AT SOUTH PLATTE
08 COLORADO
.MISSOURI RIVER .
SOUTH PLATTE
21COL001 77777777
0000
MPM CONF /10OWL
.MPNECMED. /.100ML.
• MG/L
.HG. TOTAL UG/I
NUMBER MEAN VARIANCE _STAN DEV..COEF VAR STAND ER .MAXIMUM ...MINIMUM _ BEG DATE..END DATE-
23 808.956 1560064 1249.03 1.54399 260.440 4600.00 15.0000 68/12/11 72/08/29
19,__107.768 _ 23628.8- 153.717_. 1.42636 35.2650 490.000 .200000 68/12/11 72/08/29
10 .000000 .000000 .000000 .000000 .000000 .000000 68/10/29 72/05/10
2 .000000 —.000000 .000000 , .000000 --.000000 —.000000 70/12/29.71/02/25-
-------
Table 2
Phosphate Concentration Loads and Stream Flow in the
South Platte at South Platte, Colorado
Date Sampled Time of Day T-P04-P mg/1 T-P04-P lbs DWB2 Diver- Total Flow
sion CFS CFS
68/10/29
11
30
0.00
0
7
560
68/11/27
15
30
0.00
0
105
250
68/12/11
11
00
0.03
35
53
217
69/02/26
11
40
0.13
111
53
159
69/04/21
11
45
0.03
117
112
726
69/05/26
11
15
0.00
0
0
2,290
69/06/20
11
55
.37
3,065
0
1,540
69/07/18
11
00
.03
195
135
1,210
69/10/30
11
35
.03
53
7
329
69/11/20
10
45
0.00
0
7
217
69/12/11
10
55
.07
58
7
156
70/01/29
.017
17
0
182
70/02/26
0.00
0
0
122
70/04/23
.017
33
0
360
70/06/23
11
30
.13
681
0
974
70/07/21
11
00
.03
159
0
985
70/10/20
10
55
.15
273
0
346
70/02/25
12
05
.017
11
0
122
2 From Denver Water Board operations data
-------
STORET DATE 73/08/03
000024
Table 3 39 36 00.0 105 02 00.0 4
. SOUTH PLATTE ABOVE LITTLETON
08 COLORADO
MISSOURI RIVER
SOUTH PLATTE
21COLOO 1 77777777.
0000
MILES
11*9.*0
• •
•
« •
•
• •
4
« •
PARAMETER
NUMBER
MEAN
VARIANCE
STAN DEV
COEF VAR
.stand er
-MAXIMUM_
.MINIMUM
.BEG DATE.
FNrt 0ATF
00011
WATER
TEMP
FAHN
33
49.6970
128.033
11.3152
.227683
1.96972
69.0000
34.0000
68/11/27
72/09/28
00070
TURB
JKSN
JTU
24
81. 9416
. 21522.7
146.706
. 1.79038
.29.9463
.700.000
5.50000
63/11/27
72/04/07
00 095
CNDUCTVY
AT 25C
MICROMHO
28
394.6*3
6979.00
63.5404
.211686
15.7377
500.000
156.000
69/02/26
72/09/28
00300
DO
MG/L
15
_8.3*666
_.l.54412
.. 1.24263
.148877
. .320845
11.0000
6.00000
70/11/05
72/09/28 .. .
00310
600
5 DAY
MG/L
16
1.96875
.452973
.673033
.341859
.168258
3.50000
1.00000
68/12/11
72/08/29
0 0-00
PH
SU
33
7.72727
_. 083305
...288627
.037352
.050243
..8.80000
_7.30000.
68/11/27.
7?/n9/?a
00505
RESIDUE
TOT VOL
MG/L
12
12.5000
49.5454
7.03685
.563108
2.03194
23.0000
4.00000
68/12/11
72/04/07
0 C 515
RESIDUE
DISS-105
C MG/L
25
232.360
.3212.37
56.6778
_.243922
..11,3356
.. 310.000
114.000
63/11/27
72/06/23
00530
RESIDUE
TOT NFLT
MG/L
12
81.3333
6452.07
80.3247
.987599
23.1877
238.000
7.00000
68/12/11
72/04/07
. 00545
RESIDUE
settlble_
Ml./L
13
...407692
.724102
.850942
.2.08722
.236009
.3.20000
.100000
68/12/1 I
72/08/29
00610
NH3-N
total
MG/L
22
.13*091
.036111
.190029
1.41717
.040514
.800000
.000000
68/11/27
72/04/07
0 0 615
N02-N
total
MG/L
23
.0^5870
.002171
.046592
1.29894
.009715
.. . 140000
oooooo
68/11/27
72/04/07
0:620
N03-N
total
MG/L
26
2.16923
15.1325
3.89006
1.77691
.762903
20.0000
.000000
68/11/27
72/04/07
00550
T PO*
P04
MG/L
23
.332608
.385365
.620778
1.86639
129441
3.00000
,000000
69/11/27
72/04/07.
00^20
CYANIDE
CN.
MG/L
12
.000000
.000000
.000000
.000000
.000000
.000000
69/05/29
72/04/07
00^00
TOT HARD
CAC03
MG/L
23
138.739
1064.75
32.6305
.235194
6.80394
192.000
55.0000
68/11/27
72/04/07 _.
00910
CALCIUM
CAC03
MG/L
23
94.*348
658.170
25.6548
.271667
5.34940
137.000
4*.0000
68/11/27
72/0*/07
00920
MCA'SIUM
CAC03
MG/L
23
10.5217
_ 7.07907
2.66065
.252872
.554784
.16.0000
3,00000
68/1 1/27.
7?/n*/n7
00930
SODIUM
NA,DISS
MG/L
22
24.6818
67.9421
8.24270
.333959
1.75735
39.0000
7.00000
68/11/27
72/04/07
00^31
SODIUM
aoshtion
RATIO
. 22
.895454
.. .053790
.231927
.259005
..049447
1.30000
.400000
69/11/27
72/04/07
CO 9*0
CHLORIDE
CL
MG/L
25
30.5600
100.924
10.0461
.328733
2.00922
46.0000
6.00000
68/11/27
72/05/1C
0 0 9*5
SULFATE _
SO*
MG/L
23
53.8261
225.681
15.0293
..279220
3.13383
74.0000
22.0000
68/11/27
72/04/07
00950
fluoride
F.DISS
MG/L
13
.976923
. 110256
.332048
.339892
.092094
1.60000
.300000
69/05/29
72/0*/0 7
01000
arsenic
AS.DISS
UG/L
12
.000000
.000000
.000000
000000
. .000000
_.oooooo
69/05/29.
7?/n9/?ft
01020
BODON
BtOrss
UG/L
20
23.5000
2013.42
44.8712
I.90941
10.0335
130.000
.000000
63/12/11
72/09/28
. 01025
CADMIUM
CD,DISS
. UG/L
23
_ .173913
..695652
... .834058
..4.79583
...173913
.. 4.00000
. .000000'
63/11/27
72/09/28
01032
CHROMIUM
hex-val
UG/L
11
.000000
.000000
.000000
.000000
.000000
.000000
69/05/29
72/05/10
.010*0
COPPER
CU-DISS _
..... UG/I... .
11
_ .000000
.. .000000
. .000000
.
_. .000000
.000000
..000000
69/05/29
72/05/10
010*5
13 On
total
UG/L
2*
397.500
255507
505.477
1.27164
103.180
2*00.00
•oooooo
68/11/27
72/09/28
010*9
LEAD _
PB.OISS
UG/t
11
.. .000000
000000
. .000000
_ . .
_. 000000
... .000000
oooooo
69/05/29
72/05/10
01055
mangnese
MM
UG/L
23
32.6087
21274.7
145.858
4.47299.
30.4136
700.000
.000000
68/11/27
72/09/28
01062
MOLY
M0»T0T
UG/L
1
.000000
_ .000000
.000000
72/09/28
J2/09/28
01075
SILVER
AG.DISS
UG/L
7
.000000
.000000
.000000
.000000
.000000
.oooooo
69/02/26
70/12/21
01090
2 IMC
ZNtDlSS.
UG/L
23
.64.3478
.36771.1
_191.758
. 2.98002
_ .39.9843
. 76G.'000
.. .000000
68/11/27
72/09/28
o: i--5
SELENIUM
SE.DISS
UG/L
23
.43*783
2.16601
1.47174
3.38499
.306878
6.00000
.000000
68/11/27
72/09/28
0 i 50 1
ALPHA
TOTAL
PC/I.
6
9.5S000
_5«69902.
.2.38726
_ .,249975.
974596
...12.3000
5.60000
69/05/29.
.72/09/28
05502
ALPHA-T
ERROR
PC/L
6
9.39999
9.86006
3.14007
.334050
1.28193
13.3000
4.80000
69/05/29
72/09/28
03501
. beta ..
. TOTAL
.. ... PC/L
1
10.1000
. 10.1000
.10.1000
70/04/28
70/04/28
03502
BET A-T
ERROR
PC/L
1
9.20000
9.20000
9.20000
70/04/28
70/04/28
-------
Table 3
INDEX
v.HES
~ A ~ M
C9b03
09 = 04
31 b05
31615
38260
71900
1021500 _
1149.40
eter _
PA-226
RA-226-D
TOT COH
TEC COLL.
MBAS
MERCURY
0 01) 0/4
39 36 00.0 105 02 00.0 4
SOUTH PLATTE ABOVE LITTLETON
08 COLORADO
...MISSOURI RIVER .
SOUTH PLATTE
21COL001 77777777
0000
disolved
ERROR
MPN CONF
„MPNECMED_
_HG •TOT AL_
PC/L
PC/L _
/100ML
/100ML.
MG/L
NUMBER.
1
1
29
27
23
.MEAN ..VARIANCE J5TAN. DEV_COEF!_VAR-.STAND _ER~MAXIMUM MINIMUM . .BEG DATE END DATEL
.160000 .160000
.090000 _ .. ... . .090000
866.483 1592418 1261.91 1.45636 234.331 5420.00
_199.481 50309*2 _224.297 1.12440__43.1660 790.000
.000000 .000000 .000000 .000000 .000000
.160000
.090000
30.0000 68/12/11
72/09/2B 72/09/28
72/09/28 72/09/28
lO 0 00 QQ . 0.0.0.0 0 0 . 0 0 00 Q 0.
72/08/29
2.00000 68/12/1L.72/08/29.
.000000 68/11/27 72/06/23
_..Q 00 0 0 0. «JD 0000 Q » 0 0 Q 0 0 0_l£t/ 11Z0 S_72/0 3/20
-------
The Corps of Engineers, in their recreation plans for Chatfield Reservoir,
have included body contact recreation development which the present and proposed
State standards do not recognize. The Denver Water Board is also on record that
their policy is no body contact recreation in any Denver Water Board water sup-
ply, whether a river, lake or reservoir. The State has also said that Colorado
policy is that there be no body contact recreation classification above 7,500 ft.
elevation.
With the filling of Chatfield Reservoir and with the City of Littleton's
proposed park along the South Platte below Chatfield Dam, it can be expected
that strong public pressures will be exerted to have the South Platte from
Bowles Avenue to Waterton, including Chatfield Reservoir, be classified for body
contact recreation.
Presently, Plum Creek's major use is probably that of a drainageway for
summer storms and as a conveyor of wastewaters from the few communities on the
creek. However, with the transition of Douglas County from a rural county to a
Denver bedroom community the use of the creek and flood plain as greenbelt and
open space land will be of equal importance to its present uses.
IV. Assessment of Present Water Quality and Waste Dischargers in Segment
a. South Platte above Waterton - Water quality samples in this area show no
significant problems. Dissolved oxygen is near saturation with fecal coliform
and nutrients generally low and not a problem. Samples taken since 1968 at
South Platte, Colorado, R.M. 350 by the Colorado Department of Health are shown
in Table 1. (Colo. #201 at South Platte)
Point sources above Waterton are from the few small communities in the area.
The Denver Water Board samples tnese point sources and from their data it appears
that the major problem from some of these sources is poor disinfection resulting
in high total and fecal coliforms in the discharges.
- 6 -
-------
The data at South Platte show that there are no violations of the present
A or B classifications at South Platte. This is due to the small wastes flows
and distance traveled. Table 4 lists point sources and estimated loads.
An analysis was made of the phosphate concentrations and total pounds of
phosphates in the South Platte River at South Platte to see if the Denver Water
Board diversions from Dillon Reservoir were introducing significant amounts of
phosphorous which could affect the water quality in Chatfield Dam Reservoir.
Analysis of the available data shows no correlation between phosphorous concen-
trations or loads in the South Platte and the amount of water that was diverted
by the Denver Water Board down the North Fork of the South Platte,
b. South Platte Below Waterton and Plum Creek - Water samples are taken in the
South Platte River at River Mile 330 above Littleton.
At present there are no sampling stations on Plum Creek. Water samples
taken at R.M. 330 reflect the effects of dischargers in both Plum Creek and
the South Platte River below South Platte, Colorado. Samples taken since 1968
at this station by the Colorado Department of Health are indicated in Table 3.
There were no stream violations for D.O. or fecal coliform. However, the mean
value of total phosphates and ammonia doubled in concentration, while nitrates in-
creased by over a factor of 10; between R.M. 350 and R.M. 334.9.
R.M. 350 R.M. 334.9
T-P0 -P mg/1 0.05 0.11
NH3-N mg/1 0.07 0.13
N03-N mg/1 0.19 2.18
While these concentrations presently exceed EPA recommended limits for stream
to prevent alqal problems, no evidence of such problems has been noted by EPA.
However, with the filling of Chatfield Reservoir the previous nutrient levels could
create problems in the reservoir.
The major point sources in this reach are the Martin Marietta Company on the
South Platte and the DuPont Company and the town of Castie-Rock on Plum Creek.
Table 4 lists the loads discharged .by these soiucces.
- 7 -
-------
- 8 -
A 1971 EPA investigation of fecal coliform sources in the South Platte
below Waterton concluded that if proper disinfection practices are observed
at the Martin Marietta Wastewater Treatment Plant, fecal coliform standards
for a B3, (body contact) classification could be met below Waterton except
during heavy runoff conditions when non-point sources would probably result
in fecal coliform violations.—/ With the filling of Chatfield Reservoir it
will be essential that good disinfection be practiced by Martin Marietta.
The Roxborough Park area does not appear to be a potential problem
since the development will reuse the wastewater treatment plant effluent on
a golf course and greenbelt area,
V. Future Water Resource Projects and Dischargers in Segment
a. Water Resource Projects - (1). The Denver Water Board presently imports
40,000 to 80,000 acre-feet of water from Dillon Reservoir in the Blue River
Basin to the North Fork of the South Platte. The DWB currently has
sufficient water available in the Blue River Basin to divert up to 106,000
acre-feet to the North Fork; by 1985 it will be diverting that much water to
the North Fork. If the Eagle-Piney project is developed, it will increase
the flow even more.
Presently, the nutrient concentrations in the South Platte are low enough
that they are not causing problems. However, if and when the DWB diverts this
additional flow, nutrient levels in Dillon Lake may have to be limited to pre-
vent problems in the South Platte Basin, especially with Chatfield Reservoir
in operation. To date, there have not been any studies conducted to determine
critical nutrient levels for the South Platte river or Chatfield Reservoir.
(2). The Bureau of Reclamation has proposed construction of two dams on the
South Platte between the communities of South Platte and Waterton in Platte
Canyon. The purpose of these dams is for power generation and water storage
for the Metropolitan Denver Area. The Two Forks Dam would,provide for the
3 South Platte Survey of 1971 by DFIC, EPA.
4 Bacteriological Investigations of the Upper South Platte River Basin,
Technical Support Branch, Surveillance & Analysis Division, EPA, Region VIII
-------
power pool and water storage while the Turkshead Dam, approximately four miles
downstream, will be a re-regulating dam. The Two Forks Dam will provide for
975,000 acre-feet total storage and create a, lake of 6,215 surface acres. The
Bureau has prepared an environmental assessment for the project, but the assess-
ment does not appear to adequately deal with the possible nutrient problem
which could be caused by the additional Dillon Reservoir Diversions since the
environmental assessment presumes that the waters of Dillon Reservoir will
continue to be of a high quality.
(3). An alternative to constructing the dams in the Platte Canyon identified
in the above assessment is the transfer of surplus Blue River Basin water
from the Platte Canyon to Plum Creek and the construction of a dam and reser-
voir on Plum Creek to provide the required water storage. If this alternative
should be selected, dischargers in Plum Creek will have to be examined in more
detail to determine what effluent quality will be required to meet the stream
standards.
b. Projected Load Increases - (1). The South Platte Above VJaterton - Wi th
the proposed Two Forks Dam and Reservoir, some existing communities in the
project area will have to be relocated, At that time new wastewater treatment
facilities would be constructed for the communities.
The population in the South Platte Basin below South Park probably will
not grow significantly because most of the land is Forest Service land and
therefore is not available for development.
The South Park area probably will experience a significant increase in
summer homes if the State does not impose stricter land use controls. For the
purposes of this study the only point sources projected for the next 2-5 years
are the existing ones discharging at full present capacity.
(2). South Platte below Waterton - The area in Jefferson County tributary to
Chatfield Reservoir is expected to grow significantly in the next 2-5 years,
- 9 -
-------
Fic-i' itv
Location
Plant Description
Stream
River
Mi 1 e
County
Stream
Class
Fa i rp1 ay
M i d d 1 e
Fork of
the Sout
Platte
G S C
Camp
Geneva
Si B a s i In
Santa
Maria
Bei1ey
5.0.
North
Fork at
, Platte
Perry
Park
Castle
P.cck S.D.
Si 1 ver
Heights
S.D.
Louvi ers
S . D.
Dupont
Co.
W. Plum
Creek
443A
445A
350/46
350/29
350/20
356/25
336/15
336/12
336/7.3
336/6.3
Park
aPark
Park
Park
douglas
Doug!as
A, B1, C,
D1
Unci ass.
Unclass.
Aerated Lagoon
Extended Aeratic
Extended Aeratic
n
Lagoon
Extended Aeratic
n
Extended Aeratlcn
Aeration Lagoon,
2 polishing
Lagoons
Lagoon
2-1agoons
(1) Cooling water
¦ discharges
(2) Process water
D1scharge
Iduie t
Pop. Equiv.
Design Cap
700
300
t«ddl
100
200
300
300
2,500
100
350
Nor
PI
Pop. Equiv. Est; Present Effluer.t
Served
400
300
; Fork Tota
100
100
300
th Fork Tota
300
1&
1 ,800
165
350
jui Creek Tot
FLOW
mad
0.05
0.05
no
0.01
0.01
0.03
fii"
TO.
.03
0.2
0.01
0.04
1.0
0.5
all
a
JJl
30
40
40
50
40
20
35
40
40
J3 i "tV
12
17
TT
3
10
T5~~
5
56
13
TT
P0 4
esZl
F s c a 1
lb J r/ico-.l
3.2
3.2
37?"
>1
>1
2.0
4
20
12
1 .0
UK
UK
10,000
5,000
UK
UK
UK
1 "
lnt.h«r
(NO3+MH3)
30 mgll
or 120 lb
-------
labie 4
Facility
Location
Plant Description Pop. Equiv
Stream
River
Mile
County
Stream
Class
Design Cap
Martin
Marrietta
Denver U.B.
Main Stem
of the S.
Platte
341.1
Jefferson
A, Bif C.
D1
339.0
Trickling Filters 0.5 mgd
1n series with
clarltiers for sani
tary wastes, discharge
after disinfect.
Batch treatment of
Indust. wastes with
lime, clarification
I riischarae. For
untreatable wastes,
discharge to evapora-
tion lagoon.
Washing of 1nf1H-
tratlon galley sand
on a semi-annual
basis.
N/A
N/A
Pop. Equlv. Est; Present Effluent Quality
Served
FLOW
mod
bod5
mnlT
If?
PO4
mqll
lb
Fecal
#/l 00ml
5,000 max.
0.5mgd
40
170
15
50
5.000
0.5
0
0
0
5
10
0
N/A
N/A
N/A
N/A
N/A
N/A
N/A
-------
but will probably not have any wastewater treatment plant which will dis-
charge to the reservoir. The City of Littleton has contracts with sanitary
districts in nearby Jefferson County areas which will probably serve this
area.
The Martin Marietta plant has industrial wastes which include hexavalent
chrome, but no significant amounts of this material or other heavy metals have
been found at the R.M. 330 sampling location. This may be due to the fact
that, at present, Martin discharges its "potent" industrial wastes in an evapo-
ration pond on Company property.
(3). Plum Creek - This drainage area is the area which will probably experience
the most growth in the next 2-5 years with increases in most existing discharges
and the introduction of new dischargers such as Castle Pines if the development
is approved. The Perry Park development intends to use its effluent for golf
course irrigation within the community. If this course of action is followed it
will eliminate one of the largest potential dischargers in Plum Creek. The
Roxborough Park development also intends to utilize land disposal.
There are no projected new industrial waste flows in the area. Because
of the proposed urban development in the Plum Creek Basin, non-point source
pollution could be a significant pollution source in the future although at
present its impact in the basin is estimated to be minimal.
VI. Effluent Standards
(a). Federal - The EPA has promulgated secondary treatment standards which
must be met by all municipal dischargers by July 1, 1977, These are attached in
the Appendix. EPA is developing BPT effluent guidelines for industries; at the
present time there are no National BPT effluent guidelines for the Martin
Marietta or the Dupont industries, (b). State - The State of Colorado has
adopted effluent standards for the State effective on January 15, 1973, with
two additional steps effective July 1, 1975, and July 1, 1978. On these
- 10 -
-------
dates the State standards will be more restrictive than Federal standards
with the exception of fecal coliform limitations. The State standards are
attached in the Appendix.
At present it is EPA Region VIII's policy to require point sources to
meet the most strict legal discharge requirements, be they State or Local.
VIII. Maximum Allowable Loads - A water quality model for the South Platte River
Basin has been developed for EPA. This basin model of the South Platte
extends from the outlet of Eleven Mile Reservoir on the South Platte to
Julesburg and includes the North Fork of the South Platte and the Plum Creek
tributaries to their headwaters. This model was used in developing the waste
load allocations for the Upper South Platte Segment. The South Platte above
Eleven Mile Canyon Reservoir was analysed using the "Simplified Mathematical
Modeling of Water Quality" developed for EPA. Table 5 has the estimated
flows from the point sources that are expected to be discharging in 1978.
(a). Middle Fork Reach - Application of the Colorado 1975 effluent standards
and the Federal 1977 secondary treatment effluent standards to the two present
dischargers at the estimated 1978 flows showed that the stream standards would
be met.
Theaialysis showed a 0.2 mg/1 D.0, deficit with a minimum D.O. concentra-
tion of 6.8 mg/1.
The NH3-N concentration expected in the stream at 1978 estimated flows
is 0.28 mg/1 and does not appear to be a potential problem. The EPA and the State
has not yet adopted a limitation for ammonia concentrations for protection cf
fisheries but this concentration should not create toxic conditions for fish.
Expected total phosphate concentrations at 1978 estimated flows are 0.08
mg/1 T-PO4-P which is below EPA and proposed state stream standards for flow-
ing streams and should present no problems.
Table 5 contains the projected waste flows and required effluent quality
- 11 -
-------
to meet 1977 stream and effluent standards.
To be sure that stream standards will not be violated a safety factor
should be applied in determining! the maximum allowable loads. For nearly
pristine waters such as the South Platte above Waterton it is believed that
a high factor of safety should be used, and from the analysis of D.O. sag
it is believed that the effluent limits studied would provide a sufficient
factor of safety.
Assumptions used in applying the model were:
(1). Treatment Level - High Rate Biological
(2). Design low flow - 10 cfs
3). Depth of stream - 1-2 feet
4). Background D.O. deficit - Zero
(5). Background TPO4-P and NH-j-N concentration - Zero
(6). D.O. at saturation at 9,000 feet elevation at low flow conditions
at a temperature of 16 C - 7.0 mg/1
(7). pH of water at low flow - 7.0
(b). North Fork - The analysis of this tributary indicates that if the present
dischargers with projected 1978 flows meet the 1975 and 1978 State effluent
standards, and 1977 Federal effluent standards then stream standards would be
met.
The analysis showed a 0.06 mg/1 D.O. Deficit with a minimum D.O. concen-
tration of 6.8 mg/1.
The NH3-N concentration expected in the stream at estimated 1978 flows
is 0.2 mg/1 NH3-N and does not appear to be a potential problem at this concen-
tration.
Expected T-PO4-P concentrations at 1978 estimated waste flows are 0.1
mg/1 which is at the recommended maximum EPA and proposed state stream standards
for flowing streams. If Two Forks Dam and Reservoir is constructed, the exist-
ing dischargers may be required to have phosphorous limitations on their effluent.
Additional studies should be made in the future to determine what nutrient levels
will create water quality problems in this segment. (See Section VIII: Nutrient
Analysis of Chatfield Reservoir)
- 12 -
-------
Assumptions used in applying the model were:
(1). Design Low Flow - 125 cfs
(2). Background D.O. Deficit - Zero
(3). Background T-PO4-P - 0.01 mg/1
(4). Background NH3-N - 0.02 mg/1
(5). D.O. at saturation at 8,000 foot elevation at low flow conditions
at a temperature of 16 C - 6.8 mg/1
(6). pH of water at low flow - 7.0
From the expected water quality it appears that a sufficiently high safety
factor is present to meet stream standards under all conditions.
(c). Plum Creek Reach - The analysis of this tributary indicates that if the
present and expected dischargers for 1978 meet the 1978 State effluent stand-
ards and the 1977 Federal effluent standards, then stream standards will be
met.
The analysis showed a 2.2 mg/1 deficit with a minimum D.O. of 5.3 mg/1
at R.M. 6.3. If Plum Creek is classified as a B2 stream the minimum D.O.
allowable would be 5.0 mg/1.
The NH3-N concentration at 1978 waste flows is approximately 2.0 mg/1.
Since the toxic affects of ammonia to fish are dependent on the pH of the water
and since there is no data available on the pH level of Plum Creek, a program
of monitoring the in-stream pH should be instituted to determine what free
ammonia concentrations can be expected with the discharge of NH3-N concentra-
tions expected in 1978.
Expected PO^-p concentrations in the stream are 1.7 mg/1, well above desired
maximum phosphorous levels of 0.1 mg/1. As a result of the expected high nu-
trient levels; 2.0 mg/1 NH3-N, 6.4 mg/1 NO3-N 1.7 mg/1 PO4-P, algal problems
in Plum Creek and the Plum Creek Arm of Chatfield Reservoir may occur depending
on the turbidity levels in the Creek and Reservoir.
The turbidity in Chatfield Reservoir in the Plum Creek vicinity is expected
to be quite high and the Corps of Engineers is going to relocate their sailboat
harbor from the Plum Creek area because of this anticipated sediment. The pre-
- 13 -
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sence of thismuch turbidity may make algal problems in this area minimal,
and indicate again the need for more study to determine if there will be an
algal problem in the area.
Assumptions used in applying the model:
(1). Design low flow 0.5 cfs above Dupont, R.M. 6.3, and 2.6 cfs below
R.M. 6.3
(2). Background D.O. Deficit above R.M. 28 - Zero
(3). Background TPO4-P above R.M. 28 0.10 mg/1
(4). Background TNH3-N above R.M. 28 0.20
(5). D.O. saturation @ 5,500 feet elev. at low flow conditions at
a water temperature of 22.4 C - 7.5 mg/1
(6). pH of water at low flow - 7.0
(d). Below Waterton Reach - Analysis of the South Platte below Waterton which,
also includes the Plum Creek discharge reveals that at low flow conditions
(35 cfs) in the South Platte just upstream of Bear Creek the minimum D.O. will be
7.3 mg/1 at R.M. 325, using 1978 State effluent standards. This analysis did
not consider the operation of Chatfield Dam but with the BOD concentration of
1.3 mg/1 there should not be an appreciable D.O. depletion in the reservoir
from the BOD loading.
VIII. Chatfield Dam Reservoir Nutrient Analysis
Chatfield Dam will be operated with a sediment and recreation pool of some
1150 surface acres and a pool volume of some 20,000 to 25,000 acre-feet. Opera-
tion of the Reservoir will be to discharge the same volume of water that flows
into the reservoir except during periods when flood conditions prevail downstream
or when flooding conditions are expected downstream. During these periods re-
leases of water from the Reservoir will be held to a minimum, with release of
the stored floodwaters after the downstream waters have fallen below flood stage.
The average yearly flow past._the USGS gaging station at Littleton below
Chatfield Dam is 229 cfs, or 165,900 acre-feet/year. The combined total flow
into Chatfield Reservoir as measured at the USGS gaging stations at Waterton,
Colorado and on Plum Creek 7.5 miles above the mouth are 201 cfs or 145,800
acre-feet/year. The expected average year flow through the Reservoir then is
- 14 -
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approximately 150,000 acre-feet/year. With a normal recreational pool volume
of 20,000 acre-feet, the reservoir will have an average flow-through time of
20,000 x 12 = 1.6 months. Flow through the Reservoir will not be uniform how-
150,000
ever, since the Reservoir will be operated in such a manner to maintain a nearly
constant recreational pool elevation and to let outflows equal inflows. The pat-
tern of flow in the South Platte at Waterton is such that the discharges during
the months of April, May, and June and July are probably 50% of the yearly dis-
charge.
These months also correspond with the periods of greatest potential algal
problems. During these high flow months, the monthly discharge will be approxi-
mately 20,000 acre-feet which would be a turnover time of approximately one
month. However, the flow through time in the Reservoir will also be affected
by the configuration of the lake, differences in water temperature between the
lake water and the inflowing water and any stratification that is present in
the lake. Because of these factors the residence time in some of the shallower
bays and backwaters in the reservoir could be significantly greater than the
average lake residence time. For evaluation of possible eutropnication problems
nutrient concentrations in the lake are predicted to be nearly the same as if the
flow through times were based on plug flow throw through the Reservoir and complete
mixing of the lake waters. Based on this, the following nutrient concentrations are
possible depending on the level of control placed on the dischargers.
(1). Background concentration of PO^-P, NH3-N, and N03-N above the Martin Marietta
Discharge at design low flow conditions of 42.0 cfs and application of 1978 State
effluent standards for discharger-^ are:
PO4-P = 0.08 mg/1
NH3-N = 0/16 mg/1
NO3-N = 0.14 mg/1
T-N = 0.30 mg/1
Cone.
Total Load/Day
18 lbs
37. lbs
32 lbs
69 lbs
- 15 -
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EPA guidelines for nutrient limitations on reservoirs to prevent nutrient
problems are:
PO4-P 0.05 mg/1
NOg-N maintain present levels that are
are not causing problems.
It can be seen that even at background conditions this concentration is
exceeded and eutrophication problems could develop, especially in shallow areas
on the reservoir. However, these concentrations are guidelines only and do not
guarantee what the algal response will be at higher or lower phosphorous concen-
trations.
(2). Estimated 1978 total PO^-P point source daily loadings to Chatfield Reser-
voir using 1978 state effluent standards at design low flow conditions and a
5 mg/1 P04 1 imit on Martin Marrietta discharge are estimated to be:
lb/day
North Fork 4
Middle Fork 6
Plum Creek 28 (Perry Park also included)
Martin Marietta 40
78
The total PO^-P load in the stream below the Plum Creek confluence at design
low flow of 36.2 cfs with out PO^-P removal requirement is 71.5 lbs/day which cor-
responds quite well with the estimated loading of 78 lbs/day. (See Table 6 for
nutrient concentrations at this point)
From an examination of the known point source loads above Chatfield Reser-
voir it can be seen that elimination of Martin Marietta's phosphorous loading
would eliminate nearly half of the phosphorous to the reservoir.
- 16 -
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Table 6
No Phosphorous limitations Nutrient concentration in South Platte
on dischargers. below Martin Marietta at design low flow
of 43.5 ar
PO4-P NH3-N NO3-N
mg/1 mg/1 mg/1
0.25 0.25 0.32
South Platte below Plum Creek at design low
flow of 36.2 cfs
POa-P NHtN NOtN
mg/1 mg/1 mg/1
0.36 0.38 0.83
With phosphorous limitations South Platte below Martin Marietta at design
on effluent.* low flow of 43.5 cfs
P0fl-P NH-i-N NOq-N
mg/1 mg/1 mg/1
0.11 0.25 0.32
South Platte below Plum Creek at design low
flow of 36.2 cfs
PO4-P NH3-n NO3-N
mg/1 mg/1 mg/1
0.11 0.38 0.83
*These limitations are 1 mg/1 PO4-P on all point sources on Plum Creek and on
the South Platte below Waterton.
-------
With a reduction of the phosphorous from 5 to 1 mg/1, the expected Martin
Marietta discharge would be reduced to 8 lbs, for a total point source load-
ing to the South Platte of 90 - 32 = 58 lbs/day.
If the Castle Pines development does not materialize, that will elimi-
nate 7 lbs, leaving a total of 28 - 7 = 21 lbs/day from point sources.
The only other significant point source is Castle Rock which is projected
to contribute 11 lbs. If this source is eliminated it would result in a point
source loading from Plum Creek of 28 - 18 = 10 lbs/day, which is largely from
the Perry Park discharge (7 lbs). If Perry Park goes to land disposal this
would reduce the point source loading to 4 lbs. on Plum Creek. The total point
source loading to Chatfield Reservoir then would be 78 lbs. (32 + 7 + 11 + 7) = 21
lbs/day. Of these 21 lbs., 6 lbs. are from the Middle Fork and probably are
beneficial as far as the Upper Reservoirs on the South Platte are concerned since
these reservoirs have low nutrient levels and are not very productive as fisheries.
As previously noted, Water Quality data taken at South Platte, Colorado does not
reflect any correlation between stream flow and phosphorus concentrations. There-
fore, it was assumed that the phosphorous concentrations in the South Platte in
this stretch are more or less constant and do not very with flow. If this is
so, then during low flows to Chatfield Reservoir the effect of point source
loadings from Plum Creek and Martin Marietta would not result in a significant
increase in phosphorus concentrations in Chatfield Reservoir, if dischargers of
phosphorous in Plum Creek and Martin Marietta are controlled. This is shown
below:
Est. Ave. Flow at Waterton = 200 cfs
Assumed background = P0*-p = 0.08 mg/1
Load in stream = 0.08 (8.34) (200) = 86 lb/day
1.55
Summary
A waste load discharge of 80 lbs from Plum Creek and Martin Marietta
would result in a doubling of stream concentration to approximately 0.16 mg/1.
- 17 -
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If the Martin Marietta discharge were to be reduced from 40 lbs. to 8 lbs. and
the Plum Creek discharges were reduced from 40 lbs. to 4 lbs., the total load
of 14 lbs. would produce an increase to 14 x 0.08 = 0.094 mg/1, which is only
W
0.014 mg/1 above expected phosphorous concentrations above the Martin discharge.
Additional study will be required on Chatfield Dam reservoir to attempt to
determine what the response of the reservoir water will be to various nutrient
concentrations. With this information it should be possible to determine if a
problem will arise from projected nutrient concentrations and if so what limi-
tations should be imposed on dischargers to insure that use of the reservoir
will not be impaired.
IX. Basin Strategy and Permit Priorities
Basin Strategy - EPA Region VIII strategy in the Upper South Platte Basin
Segment was expressed last year in the South Platte Priority Accomplishment Plan
which called for the elimination of all point sources in this segment of the South
Platte. This is still Region VIII policy and in accordance with this policy EPA
strategy is to support adoption of the local Tri-County goals of no discharge
to the Souch Platte and tributaries above Littleton. In furtherance of this
strategy, dischargers should be encouraged to use land disposal as an alternative
which would enhance the value and use of open space and park land in the segment
as called for in section 201(f) of the Federal Water Pollution Control Act Amend-
ments of 1972.
From the analysis of the possible impact of phosphorous on the water quality
of Chatfield Reservoir, it is Region VIII strategy to study the response of the
lake to various nutrient levels t.o^determine if there is a need to limit the dis-
charge of phosphorous from point sources in this segment. In the meantime per-
mits should be issued on a short term basis so that the reissuance of the permit
can be made using tlte data available from nutrient studies
- 18 -
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Permit Priorities
1. Require point source dischargers in South Platte above Waterton and
on Plum Creek to meet present State secondary treatment effluent
standards for disinfection by 6/74.
2. Require point source dischargers abovfe Waterton to meet present State
effluent standards by 6/74 and to meet 1975 and 1978 State effluent
standards on the applicable dates.
3. Require E.I. Dupont to go to no discharge of process water waste if
possible by Jan. 1975. Limits for discharge of process water if
discharged are shown on Table V.
4. Require Martin Marietta to meet present State effluent standards by
1/74 with limitation of PO^-P of 5 mg/1 by 7/74. Seek to have
Martin Marietta reach no discharge by July 1977, through reuse of waste-
water.
Construction Grant Priorities - Presently the municipal point sources in the
Upper South Platte have low priority ratings in the 1974 106 State Program Plan.
Because of the number of communities with higher priority ratings, the Upper
South Platte communities will likely not receive funds in FY 75 or 76 unless
funding increases considerably or priorities are reordered.
- 19 -
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Table 5
Facility
Required Eff.-77
Needs
FLOW
mgd
B0D5
mg/1
lb
PO4
mg/1
lb
Fecal
#/100 ml
State municipal
Inventory Priori-
ty number
Falrplay
.07
25
14
8
3
200 (5,000 now)
Put 1n filtration to meet 25 mg/1 BOD5
None
6/75
6/78
25mg/l
20mg/l
BOD5
BOD5
G&C Camp
.05
25
10
8
3
200 (5,000 now)
Provide for no discharge, or put 1n filtration to .
meet 25 mg/1 BOD5
N.A.
6/74
30mg/l
BOD5
Middle Fork
T otals
0.10
24
6
Geneva Sk1
Basin
.01
25
2
8
1
200 (5,000 now)
Provide adequate disinfection; put 1n filtration to
meet 25 mg/1 BOD5
None
6/75
6/78
25mg/l
20mg/l
BOD5
BOD5
Santa Maria
0.01
25
2
8
1
200 ( " )
Provide filtration or adequate lagoon capacity for
no discharge
None
6/75
6/78
25mg/l
20mg/l
BOD
BOD
Bailey S.D.
0.03
25
6
8
2
200 ( " )
Provide adequate disinfection Immediately. Put In
polishing pond and/or filtration to remove BOD5 to
25mg/l
6
6/75
6/78
25mg/l BOD5
20 mg/1 B0D&
N. Fork Totals
0.05
8
4
Perry Park
.2
20
21
200 ( " )
Provide filtration of plant effluent to reduce BOD5,
or go to land disposal.
24
6/75
6/77
25mg/l
20mg/l
bod5
BOD5
Castle Rock,
S.D.
.3
20
32
200 ( " )
Provide filtration of lagoon effluent to reduce BOD;
and SS, or go to land disposal.
24
6/75
6/77
25mg/l
20mg/l
B0D5
BODg
Silver Heights
.02
20
2
200 ( " )
Provide additional lagoon capacity to provide no dl;
charge use-percolation and evaporation
6
6/75
6/77
25mg/l
20mg/l
BODc
BOD5
Louvlers, S.D.
.04
20
-
4
200 ( " )
Provide sufficient lagoon volume to have no dlscharc
use evap. and/or percolation
e N.A.
6/75
6/77
25mg/l
20mg/l
BOD5
BOD5
Compliance Date
-------
Table 5 (con't)
Facility Required Eff.-77 Needs Compliance Date
FLOW
mgd
BODc
mg/1
lb
P04
mg/1
lb
Fecal
#/100 ml
State municipal
Inventory Priori-
ty number
Dupont Co.
(cooling water)
0.7
10
58
0
0
N.A. (")
Institute tight process controls and keep process
waters out of cooling water system. To eliminate
highest levels of NO^ & NHj 1n present effluent.
N.A.
Reduce NH,-N to 1
mg/1 and ilOp-H,
NO3-N to 5 mg/1
Immediately.
Dupont Co.
(process water)
0
0
N.A. (")
Eliminate high NH3 and N03 loadings.
N.A.
Reduce to 1
mg/1 immediately.
Reduce il0?-H +
NO3-N to 5.0 mg/1
by 1/75
Castle Pines
0.2
20
33
Provide phosphorous removal, or go to land dis-
posal.
Upon construction
of new facility.
Plum Creek
Total
1.46
150
9
I'artin
Marrietta
1.0
20 '
167
5
40
200
Martin putting In reactor-clarlfler for settling
of lime treated combined munlc. and Industrial 1
wastes before discharge to 2 polishing ponds In 1
series.
1/74
Denver W.B.
'
i
ha.
N.A.
Meet BAT Guidelines.
6/74
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