U.S. ENVIRONMENTAL PROTECTION AGENCY
NATIONAL EUTROPHICATION SURVEY
WORKING PAPER SERIES
REPORT
ON
POWDER MILL POND
HILLSBOROUGH COUNTY
I€W HAMPSHIRE
EPA REGION I
WORKING PAPER No, 14
PACIFIC NORTHWEST ENVIRONMENTAL RESEARCH LABORATORY
An Associate Laboratory of the
NATIONAL ENVIRONMENTAL RESEARCH CENTER • CORVALLIS, OREGON
and
NATIONAL ENVIRONMENTAL RESEARCH CENTER - LAS VEGAS, NEVADA
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REPORT
ON
POWDER Mill POND
HILLSBOROUGH COUNTY
ie HAMPSHIRE
EPA REGION I
WORKING PAPER No, 14
WITH THE COOPERATION OF THE
NEW HAMPSHIRE WATER SUPPLY AND POLLUTION CONTROL COMMISSION
AND THE
NEW HAMPSHIRE NATIONAL GUARD
AUGUST, 1974
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1
CONTE NTS
Page
Foreword ii
List of New Hampshire Study Lakes iv
Lake and Drainage Area Map v
Sections
I. Conclusions 1
II. Introduction 3
III. Lake and Drainage Basin Characteristics 4
IV. Lake Water Quality Summary 5
V. Nutrient Loadings 10
VI. Literature Reviewed 17
VII. Appendices 18
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11
FOREWORD
The National Eutrophication Survey was initiated in 1972 as a
research project in response to an Administration commitment to
investigate the nationwide threat of accelerated eutrophication to
fresh water lakes and reservoirs.
OBJECTIVES
The Survey was designed to develop, in conjunction with state
environmental agencies, information on nutrient sources, concentrations,
and impact on selected freshwater lakes as a basis for formulating
comprehensive and coordinated national, regional, and state management
practices relating to point-source discharge reduction and non-point
source pollution abatement in lake watersheds.
ANALYTIC APPROACH
The mathematical and statistical procedures selected for the
Survey’s eutrophication analysis are based on related concepts that:
a. A generalized representation or model relating
sources, concentrations, and impacts can be constructed.
b. By applying measurements of relevant parameters
associated with lake degradation, the generalized model
can be transformed into an operational representation of
a lake, its drainage basin, and related nutrients.
c. With such a transformation, an assessment of the
potential for eutrophication control can be made.
LAKE ANALYSIS
In this report, the first stage of evaluation of lake and water-
shed data collected from the study lake and its drainage basin is
documented. The report is formatted to provide state environmental
agencies with specific information for basin planning [ 3O3(e)],
water quality criteria/standards review [ 3O3(c)], clean lakes [ 314(a,b)],
and water quality monitoring [ 5106 and 5305(b)] activities mandated by
the Federal Water Pollution Control Act Amendments of 1972.
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111
Beyond the single lake analysis, broader based correlations
between nutrient concentrations (and loading) and trophic condi-
tion are being made to advance the rationale and data base for
refinement of nutrient water quality criteria for the Nation’s
fresh water lakes. Likewise, multivariate evaluations for the
relationships between land use, nutrient export, and trophic
condition, by lake class or use, are being developed to assist
in the formulation of planning guidelines and policies by EPA
and to augment plans implementation by the states.
AC KNOWL EDGMENT
The staff of the National Eutrophication Survey (Office of
Research & Development, U. S. Environmental Protection Agency)
expresses sincere appreciation to the New Hampshire Water Supply
and Pollution Control Division for professional involvement and
to the New Hampshire National Guard for conduct of the tributary
sampling phase of the Survey.
William A. Healy, Executive Director of the New Hampshire Water
Supply and Pollution Control Commission, Ronald E. Towne, Water
Pollution Biologist, and Kenneth MacDonald, Chief Water Pollution
Sanitarian, provided invaluable lake documentation and counsel during
the course of the Survey.
Major General Francis B. McSwiney, the Adjutant General of New
Hampshire, and Project Officer Lieutenant Colonel Russ Grady, who
directed the volunteer efforts of the New Hampshire National Guards-
men, are also gratefully acknowledged for their assistance to the
Survey.
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iv
NATIONAL EUTROPHICATION SURVEY
STUDY LAKES
STATE OF NEW HAMPSHIRE
LAKE NAME COUNTY
Glen Lake Hillsborough
Lake Winnipesaukee Carroll , Belknap
Kelly’s Falls Pond Hilisborough
Powder Mill Pond Hillsborough
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I HILLSB0R0ij CO.
CHESIBRE Co.
POWDER MILL
POND
enfi.Id
Tributary Sa 1ing Site
Lake Samrlinn Site
Sewage Treatn nt Facility
Direct Drainage Area Boundary
9.
Scale
‘Si
I
/
I
-J
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POWDER MILL POND
STORET NO. 3302
I. CONCLUSIONS
A. Trophic Condition:
Survey data and the records of others show that Powder Mill
Pond is eutrophic. Although algal blooms are rare, rooted aquatic
vegetation is common to abundant in the shallower parts of the
Pond. Apparently, the short hydraulic retention time suppresses
trophic responses to relatively high nutrient loading rates.
B. Rate-Limiting Nutrient:
At the time the algal assay sample was collected (10/04/72),
Powder Mill Pond was phosphorus limited; however, Pond data ob-
tained in June and August indicate the Pond was nitrogen limited
at those times.
C. Nutrient Controllability:
1. Point sources--During the sampling year, Powder Mill
Pond received a total phosphorus load at a rate well in excess
of that proposed by Vollenweider (in press) as dangerous (i.e.,
a eutrophic rate; see page 17). Of this load, it is estimated
that the Town of Jaffrey contributed nearly 32%, and the Town
of Peterborough contributed about 20% (see Appendix D).
In the following table, the total phosphorus loading rates
that can be achieved by the specified levels of phosphorus re-
moval at the two point sources are compared to Vollenweider’s
suggested rates.
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Total P Loadin
% P Removal lbs/acre/yr g/m /yr
Existing 29.0 3.25
50 21.5 2.40
70 18.4 2.07
80 16.9 1.90
90 15.4 1.73
100 13 9 1.56
Vollenweider (g/m 2 /yr):
Dangerous (eutrophic rate) 2.20
Permissible (oligotrophic rate) 1.10
It will be noted that 70% phosphorus removal would result in
a loading rate a little less than a eutrophic rate, but none of
the above options would result in a permissible or oligotrophic
rate.
Although some improvement in the trophic condition of the
Pond would be expected with the reduction in phosphorus loading
resulting from 80% to 90% phosphorus removal at the point sources,
it is questionable whether the degree of improvement would be
commensurate with the costs of the high level of phosphorus re-
moval required.
2. Non-point sources--The mean nutrient exports of Powder
Mill Pond tributaries were quite low during the sampling year
(see page 17) and compared very favorably with Lake Winnipesaukee
tributaries (see Working Paper No. 11 , “Report on Lake Winnipesau-
kee”).
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II. INTRODUCTION
Powder Mill Pond is an impoundment of the Contoocook River near
Bennington, New Hampshire. The Pond is owned by Monadnock Paper Mills,
Inc., and is controlled for water storage and river flow augmentation;
water for mill use is taken from a smaller impoundment just downstream
from the Pond (LeCain, 1973).
Reportedly, the Pond provides fair bass fishing, and some boating
is done for that purpose. However, there are no boat-launching facili-
ties, and little other recreational use is made of the Pond.
Shoreline development is minimal.
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III. LAKE AND DRAINAGE BASIN CHARACTERISTICS
A. Lake Morphometry:
1. Surface area: 372 acres.
2. Mean depth: 8.1 feet.
3. Maximum depth: ? feet.
4. Volume: 3,030 acre/feet*.
5. Mean hydraulic retention time: 6.5 days.
B. Tributary and Outlet:
(See Appendix A for flow data)
1 . Tributaries -
Name Drainage area** Mean flow**
Contoocook River 108.4 mi 2 177.8 cfs
Moose Brook 13.8 mi 2 22.6 cfs
Unnamed stream (C-l) 3.2 mi 2 5.3 cfs
Ferguson Brook 10.6 mi 2 17.4 cfs
Minor tributaries & 2
immediate drainage - 7.4 mi 13.1 cfs
Totals 143.4 mi 2 236.2 cfs
2. Outlet -
Contoocook River 144.0 mi 2 236.2 cfs
C. Precipitationh t :
1. Year of sampling: 49.6 inches.
2. Mean annual: 43.2 inches.
* Knowlton, 1974.
** Drainage areas are accurate within ±1%, gaged mean annual flows within
±15%, and ungaged mean annual flows within ±20%.
t Includes area of Pond.
tf See Working Paper No. 1, “Survey Methods”.
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5
IV. LAKE WATER QUALITY SUMMARY
Powder Mill Pond was sampled three times during the open-water season
of 1972 by means of a pontoon-equipped Huey helicopter. Each time, samples
for physical and chemical parameters were collected from one or more depths
at three stations on the Pond, except for station 1 which could not be sam-
pled in October because of a drawdown of the Pond (see Map 1, page v).
During each visit, a single depth-integrated (near bottom to surface) sam-
ple was composited from the stations for phytoplankton identification and
enumeration; and during the last visit, a single five-gallon depth-integrated
sample was composited for algal assays. Also each time, a depth-integrated
sample was collected from each of the stations for chlorophyll a analysis.
The maximum depths sampled were four feet at station 1, five feet at station
2, and four feet at station 3.
The results obtained are presented in full in Appendix B, and the data
for the fall sampling period, when the lake was essentially well-mixed,
are summarized below. Note, however, the Secchi disc summary is based on
all values.
For differences in the various parameters at the other sampling times,
refer to Appendix B.
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A. Physical and chemical characteristics:
FALL VALUES
(10/04/72)
Parameter Minimum Mean Median Maximum
Temperature (Cent.) 15.6 16.0 16.0 16.4
Dissolved oxygen (jng/l) 8.1 8.9 8.9 9.7
Conductivity (pmhos) 80 81 80 84
pH (units) 6.4 6.5 6.5 6.6
Alkalinity (mg/i) 10 10 10 10
Total P (mg/i) 0.026 0.032 0.030 0.041
Dissolved P (mg/i) 0.015 0.016 0.016 0.019
NO + NO (mg/i) 0.050 0.057 0.060 0.060
Am onia mg/1) 0.090 0.127 0.105 0.210
ALL VALUES
Secchi disc (inches)
36 47
46 61
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7
B. Biological characteristics:
1 . Phytoplankton -
Sampling Dominant Number
Date Genera per ml
06/02/72 1. Navicula 108
2. Dinobryon 88
3. Fragilaria 44
4. Flagellates 42
5. Synedra 36
Other genera 258
Total 576
08/05/72 1. Cyclotella 189
2. Flagellates 151
3. Cryptomonas 66
4. Synedra 24
5. Dinobryon 22
Other genera 139
Total 591
10/04/72 1. Flagellates 2,214
2. Fragilaria 1,160
3. Dinobryon 617
4. Melosira 467
5. Cyclotella 376
Other genera 904
Total 5,738
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2. Chlorophyll a -
(Because of instrumentation problems during the 1972 sampling,
the following values may be in error by plus or minus 20 percent.)
Sampling Station Chlorophyll a
Date Number ( ig/l )
06/02/72 01 2.2
02 2.5
03 3.7
08/05/7 2
Maximum yield
____________ _________ _________ ( mg/l-dry wt. )
0.2
0.6
1.9
2.2
2.4
26.6
0.2
10/04/72
01 2.4
02 8.6
03 3.0
01 not done
02 19.8
03 7.3
C. Limiting Nutrient Study:
1. Autociaved, filtered, and nutrient spiked —
Ortho P Inorganic N
Spike (mg/l) Conc. (mg/i) Conc. (mg/i ) _____________
Control 0.012 0.133
0.006 p 0.018 0.133
0.012 p 0.024 0.133
0.024 P 0.036 0.133
0.060 P 0.072 0.133
0.060 P + 10.0 N 0.072 10.133
10.0 N 0.012 10.133
2. Discussion —
The control yield of the assay alga, Selenastrum capri-
cornutum , indicates that the potential primary productivity
of Powder Mill Pond was relatively low at the time the sam-
ple was collected. Also, the increased yields with increased
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9
levels of orthophosphorus (up to about 0.020 mg/i), and the
lack of response to the addition of nitrogen alone, show
that the Pond was phosphorus limited when sampled; however
the nitrogen to phosphorus ratios of about 9 to 1 and 10 to
1 in June and August, respectively, indicate nitrogen limi-
tation at those times.
D. Trophic Condition:
Survey data the records of others (Anonymous, 1973) show
that Powder Miii Pond is eutrophic, although nuisance algal blooms
seldom occur despite a phosphorus loading rate of 29 lbs/acre/yr.
However, the very short hydraulic retention time results in a
little less than 10% accumulation of the phosphorus reaching the
Pond and less than 8% of the nitrogen. It appears the essentially
flow-through regime of the Pond is suppressing trophic responses
to relatively high nutrient loading rates, although the Pond
reportedly supports fairly dense growths of emergent aquatic weeds
along the shorelines.
Nuisance algal blooms have occurred in the Pond in the past;
however, New Hampshire Water Supply and Pollution Control personnel
attribute the blooms to continuations of blooms in Skatutakee Lake
some miles upstream on a tributary to the Contoocook River
(MacDonald, 1972). Since the termination of an industrial waste
discharge to the lake in 1970, no blooms have been reported in
either the lake or Powder Mill Pond.
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V. NUTRIENT LOADINGS
(See Appendix C for data)
For the determination of nutrient loadings, the New Hampshire National
Guard collected monthly near—surface grab samples from the tributary sites
indicated on Map 1 (page v), except for the high runoff months of March
and April, when two samples were collected, and the colder months of the
year when one or more samples were omitted depending on the site. Sampling
was begun in August, 1972, and was completed in July, 1973.
Through an interagency agreement, stream flow estimates for the year
of sampling and a “normalize& or average year were provided by the New
England District Office of the U.S. Geological Survey for the tributary
sites nearest the lake.
With reference to the map on page v, the tributary site originally
selected as the Pond inlet (station A-l) was later found to be in the Pond
proper. For this reason, in this report station A—2 is considered the
inlet, and nutrient loads at that point were determined by using mean annual
nutrient concentrations at A-2 and the mean annual flows provided by U.S.G.S.
for station A-i. The A-i flows were adjusted fro station A-2 by subtracting
the estimated flows of Ferguson Brook which joins the Contoocook River down-
stream from A-2.
The flows of Ferguson Brook were estimated on the basis of drainage area
(10.6 mi 2 ) times the mean discharge per square mile for the Contoocook River
drainage as determined by U.S.G.S. (i.64 cfs/m1 2 ). The nutrient loads for
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the Brook were calculated using the estimated flow and the mean annual
nutrient concentrations of Moose Brook which appears to have very simi-
lar drainage characteristics.
Also, it will be noted that the unnamed stream draining Whitteniore
Lake is not a Powder Mill Pond tributary. Sampling of this stream was
conducted at station C-i to establish nutrient concentrations for the
calculation of immediate drainage area nutrient loads (tributary ‘ZZ”
in U.S.G.S. flow data, Appendix A) and to permit adjustments of nutrient
loads leaving the system at station A-6 in Bennington, since it was im-
practical to sample the outlet of Powder Mill Pond directly. Further,
the Monadnock Paper Mills diverts about 312 million gallons per year
from a smaller impoundment just below the Pond but above station A-6;
therefore, nutrient losses through the diversion were added to A-6 loads
(i.e., A-6 loads plus diversion loads minus C-i loads = Pond outlet loads).
Discharges from the Peterborough wastewater ponds were sampled by
the operator on a monthly basis, and flow data were provided. However,
the Jaffrey operator provided only four usable samples (Appendix C); and
the Jaffrey loads were calculated on that basis. The resulting loads were
of the same order as would have been estimated by using 2.5 lbs P and 7.5
lbs N/capita/yr.
The D. D. Bean & Sons Company at Jaffrey daily contributes from 200 to
300 gallons of match-dip process wash waters to the Jaffrey system. The
effect of this phosphorus source on the phosphorus load in the Jaffrey
effluent is not known; but, considering the rather small volume, the
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source probably was not significant. Also, the Noone Woolen Mills dis-
charge to the Peterborough system apparently did not increase nutrient
loads from that source appreciably.
During the sampling year, the combined phosphorus loads from the
Jaffrey and Peterborough treatment facilities exceeded the entire phos-
phorus load measured at A-2 (thus indicating sedimentation and/or biologi-
cal assimilation of some portion of the point-source phosphorus loads in
the system). Therefore, in the following phosphorus loading table, the
loads attributed to Jaffrey, Peterborough, and the Contoocook River at
A-2 were adjusted as outlined in Appendix D. Note, however, that nitro-
gen loads were not adjusted, and the load attributed to the Contoocook
River is that measured at A-2 minus the point-source loads.
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A. Waste Sources:
1. Known municipal -
2. Known industrial** -
Mean Receiving
Flow (mgd) Water
Name
D. D. Bean & Sons
Co., Jaffrey
Noone Woolen Mills,
P e terbo rough
Treatment
(to Jaffrey
system)
(to Peter—
borough
system)
Mean Receiving
Flow (gpd) Water
200-300 (Contoocook River)
50,000-
100,000
(Contoocook River)
Name
J a ffrey
Peterborough
Pop.
Served* Treatment
2,000
2,000
stab, ponds
stab, ponds
0.661 Contoocook River
0.293 Concoocook River
* Anonymous, 1973.
** MacDonald, 1973.
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B. Annual Total Phosphorus Loading - Average Year:
1. Inputs -
lbs P/ % of
Source yr total
a. Tributaries (non—point load)
Contoocook River 3,850 35.7
Moose Brook 580 5.4
Ferguson Brook 450 4.2
b. Minor tributaries & immediate
drainage (non-point load) - 230 2.1
c. Known municipal —
Jaffrey 3,410 31.6
Peterborough 2,190 20.3
d. Septic tanks* — 10 0.1
e. Known industrial -
D. D. Bean & Sons Co. (to Jaffrey system)
Noones Woolen Mill (to Peterborough system)
f. Direct precipitation** - 60 0.6
Total 10,780 100.0
2. Outputs -
Lake outlet - Contoocook River 9,730
3. Net annual P accumulation — 1 ,050 pounds
* Estimated 20 shoreline dwellings; see Working Paper No. 1, “Survey Methods”.
** See Working Paper No. 1.
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Source
a.
Tributaries (non-point load) -
Contoocook River
Moose Brook
Ferguson Brook
b. Minor tributaries & immediate
drainage (non-point load) -
c. Known municipal -
Ja ffrey
Peterborough
d. Septic tanks * -
e. Known industrial -
D. D. Bean & Sons Co.
Noones Woolen Mill
f. Direct precipitation** -
Total
150,910
71.6
14,220
6.7
10,920
5.2
5,920
2.8
16,830
8.0
7,970
3.8
(to Jaffrey system)
(to Peterboroug system)
3,580 1.7
210,820 100.0
2. Outputs -
Lake outlet - Contoocook River 194,960
3. Net annual N accumulation - 15,860 pounds
* Estimated 20 shoreline dwellings; see Working Paper No. 1, “Survey Methods”.
** See Working Paper No. 1.
C. Annual Total Nitrogen Loading - Average Year:
1. Inputs -
lbs NI
yr
% of
total
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D. Mean Annual Non-point Nutrient Export by Subdrainage Area:
Tributary lbs P/mi 2 /yr lbs N/mi 2 /yr
Contoocook River 36 1,392
Moose Brook 42 1 ,030
Ferguson Brook 42 1 ,030
Unnamed stream (C-i) 29 740
E. Yearly Loading Rates:
In the following table, the existing phosphorus loading
rates are compared to those proposed by Vollenweider (in press).
Essentially, his “dangerous” rate is the rate at which the
receiving water would become eutrophic or remain eutrophic; his
“permissible” rate is that which would result in the receiving
water remaining oligotrophic or becoming oligotrophic if mor-
phometry permitted. A mesotrophic rate would be considered one
between “dangerous” and “permissible”.
Total Phosphorus Total Nitrogen
Units Total Accumulated* Total Accumulated*
lbs/acr /yr 29.0 2.8 566.7 42.6
grams/rn /yr 3.25 0.32 63.5 4.8
Volle 2 weider loading rates for phosphorus
(g/m /yr) based on mean depth and mean
hydraulic retention time of Powder Mill Pond:
“Dangerous” (eutrophic rate) 2.20
“Permissible” (oligotrophic rate) 1.10
* The indicated nutrient accumulations probably are too high. The Pond outlet
was not sampled directly; but at least one downstream reservoir intervenes
between the Pond outlet and the sampling station at A-6, and some portion
of the “accumulated” nutrients must have been trapped there. Further, the
fall Pond drawdown observed by EPA limnologists does not appear to be re-
flected in the A-6 flows provided by U.S.G.S.; adjustment of these flows
to include the drawdown would result in greater amounts of nutrients in
the outflow and, therefore, lesser amounts of accumulated nutrients.
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VI. LITERATURE REVIEWED
Anonymous, 1973. Merrimack River basin water quality management plan.
Staff Rept. #61, NH Water Supply & Pollution Control Comm., Concord.
Gagnon, Andre (Supt.), 1973. Personal communication (Jaffrey waste
treatment facilities). Jaffrey Dept. of Public Works.
Knowlton, Vernon, 1974. Personal cornunication (estimate of volume
of Powder Mill Pond). NH Water Resources Comm., Concord.
LeCain, Erving, 1973. Personal communication (history and uses of
Powder Mill Pond). Monadnock Paper Mills, Inc. Bennington.
MacDonald, Kenneth J., 1972. Personal communication (algal blooms
in Powder Mill Pond). NH Water Supply & Pollution Control Comm.,
Concord.
___________ 1973. Personal communication (characteristics, uses,
and trophic state of Powder Mill Pond; D. D. Bean Match Co.
wastes). NH Water Supply & Pollution Control Corn., Concord.
Vollenweider, Richard A., (in press). Input-output models. Schweiz
A. Hydrol.
Weeks, Thomas (Operator), 1973. Personal communication (Peterborough
waste treatment facilities). Waste Treatment Plant, Peterborough.
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VII. APPENDICES
APPENDIX A
TRIBUTARY FLOW DATA
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TRIBUTARY FLOW INFORMATION FOR NEW HAMPSHIRE 7/9/74
LAKE CODE 3302 PONDER MILL POND
TOTAL DRAINAGE AREA OF LAKE 144.00
SUR-ORAINAbE NORMALIZED FLOWS
TRIRUTAPY ARFA JAN F F8 MA APR MAY JUN JUL AUG SEP OCT NOv DEC MEAN
110241 119.00 198.00 183.00 314.00 572.00 284.00 150.00 68.90 52.10 71.80 96.90 175.00 181.00 195.15
310?A6 144.00 239.00 222.00 380.00 693.00 344.00 181.00 83.AO 63.10 86.80 117.00 212.00 219,00 236.19
330281 13.80 22.90 21.30 36.40 66.40 33.00 17.40 7.99 6.04 .32 11.20 20.30 21.00 22.64
3302C1 3.20 5.31 4.93 8.45 15.40 7.65 4.03 1.85 1.40 1.93 2.60 4.70 4.86 5.25
3102ZZ 8.00 13.30 12.30 21.10 38.50 19.10 10.10 4.63 3.50 4.82 6.51 11.80 12.20 13.13
SUMMARY
TOTAL DRAINAGE AREA OF LAKE = 144.00 TOTAL FLOW IN = 2839.92
SUM OF SUR—DRAINAGE AREAS = 144.00 TOTAL FLOW OUT = 2840.30
MEAN MONTHLY FLJwS AND DAILY FLOWS
TRIRUTARY MONTH YEAR MEAN FLOW DAY FLOW DAY FLOW DAY FLOW
130241 8 72 52.60 26 35.00
9 72 31.50 9 29.80
10 72 67.70 1 31.40
Ii 7’ 266.00
12 72 272.00
1 73 396.00 6 192.00
2 73 458.00 11 211.00
3 73 597.00 11 549.00 25 386.00
4 71 535.00 15 377.00 30 413.00
5 73 335.00 20 298.00
6 73 188.00 10 141.00
7 73 23?.O0 7 248.00
330246 A 77 63.70 26 42.30
9 72 38.10 9 36.00
10 81.80 1 38.00
11 72 3’2.0O
1? 7 328.00
1 73 478.00 6 232.00
2 73 555.00 11 255.00
3 71 722.00 11 664.00 25 467.00
4 73 649.00 15 456.00 30 500.00
5 73 406.Oi) 20 360.00
6 73 226.00 10 170.00
7 73 256.00 7 301.00
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r-I-i’Jr -.’y FL0 j Ir 0-U MAT1ON FOR NF ‘-I4MPS-IIPE
7,9,74
‘O E 3’ “ILL ‘-‘) ‘
‘ . ‘‘ ‘ i’ ’ ’T— Y’ ‘ L’)u’ r”fl 1I_ Y
TPJR)TA ’( 1(jrj -I ( - ‘l N Ftfl FLflW 1)AY FLOW DAY FLOW
1V12k1 7 ) ‘.1O ?6
U 7’ 3 f 5 3.45
[ 0 7? 7• 13 1 3.64
I I 7 10.00
1 ’ 1 .31. 50
1 13 45• i
2 73 3.”u 11 24.40
I T .’O 11 t,3.60 25 44.70
7 ) f’7.1 15 43.70 30 47.90
S 7 1 3 .t)O 2u 34.50
6 /3 ‘I. ’) 10 16.30
7 71 ‘e . j I ‘8.80
30 CI 7’ U.9
7’ o. - o, o
IC 7? 1.’-’’ 1 0.85
Ii 7’ 7.1’+ 4 3.05
7) 7.?9
1 1t .AO h 5.15
2 7) 12.3r) 11 5.66
3 7 16.10 11 14.80 25 10.40
4 71 14.40 IS 10.10 30 11.10
5 11 ‘4.(,0 7(1 8.00
ii 5.00 10 3•MO
5.70 7 6.7)
310 )7? 7’ 3.54
9 _7_ ’
13 72 4.5
Ii 7’ 17. ” )
I? 77 1 .i0
I 7
-, 7)
1 3 43.)”
4 7)
5 73 72 5l)
6 73 j2 )
7 73
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APPENDIX B
PHYSICAL and CHEMICAL DATA
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STOPET PETRTFVP L DATE 14/07/02
3302i) 1
4? 57 00.0 07! 56 00.’)
MOwDE. MILL DON ,)
33003 NE4 HAMPSHIRE
I I EPALFS ?111 ?02
b 0006 F’ ET DFPT-i
00010 00300 00077 OO 4 00400 00410 00630 00610 0066 00666
DATE TIME DEPTH WATER DO TRANSP CNDIJCTV ’ PH 1 ALK N02 ’ NO3 N113—N PHOS—TOT PHOS—L)IS
FROM OF TEMP SECC .-’l FIELD CACO3 t’J-TI)TAL TOTAL
TO DAY FEET C t4T ‘1C’/L I ‘ICHFS M ICMOMHO S(J G/L M(,/L MG/L M6/L ‘ MG/L P
72/06/02 06 15 0000 16.4 42 10K 0.070 0.070 0.02 ’ .
72/OR/OS 10 10 0000 75 6.10 10K 0.150 0.120 0.053 0.027
10 10 0004 0.i 110 6.20 10K 0.150 0.050 0.09’. 0.024
37217
O TE TIME DEPTH CHL’ P -1YL
FROM OF A
TO DAY FEET UG/L
72/06/0? 06 15 0000
72/0 .3/05 10 10 0000 d.4J
-------
STORET RErRIEvAL nATE 7 /O7/02
13020?
4? S’ 00.0 071 SF, 00.0
P0yJflE MILL ‘0N1)
33 NEW rlAM’5i-iI 4E
1 1F ALES 211120?
5 0006 FEET )Fi TH
DATE TIME DEPTH
FROM OF
TO DAY FF T
72/06/0? 06 40 0000
06 40 0004
72/08/05 10 25 0000
10 25 0005
72/10/04 17 35 0000
17 35 0003
DATE TIME DE°TH
FROM OF
TO t)AY FEET
WATEM
00
T 4NSP
CNOUCTVY
PH
T
ALK
NO2 N03
NH3—N
P os—Tor
PHOS—DIS
TEMP
SECCI-lI
FIELD
CACO3
N—TOTAL
TOTAL
CENT
MG/L
INCHES
M ICROMHO
SU
MG/L
Mb/L
MG/L
MG/L P
MC ’/L P
9.?
4
30
10K
0.070
- 0.060
0.026
0.014
7.6
51
40
66
5.90
6.30
10K
10K
0.060
0.100
0.060
0.170
0.024
0.054
0.015
0.023
7.2
65
10
6.30
h.4
13K
10K
0.0 0
0.060
0.120
0.100
0.053
0.033
0.026
0.015
Q•7
RO
6.60
10K
0.060
0.090
0.041
16.7
16.7
20 .
20.5
16.4
32217
CHLRPHYL
A
Li G /L
?. SJ
8.6J
19. J
72/06/0?
72/08/05
72/10/04
06 40 0000
10 ?5 0000
17 35 0000
-------
STORET ET4flEVAL DAlE 74/07/0?
3 0203
4? 5 00.4) 071 56 00.0
P0A [ E. MILL PONO
33 NEw HAUPSHII E
I IEPALES 2111202
0010 FEET DEPT 1
00010 00300 00077 000°4 00400 00410 00630 00510 00 6-5
DATE TIME DEPTH WATER DO TRANSP C PUCTVY PH 1 ALK NO? .N03 N413-N PHOS-TOT Pr’OS-PIS
FROM OF TEMP SLCCMI FIELD CACO3 N—TOTAL TOTAL
TO DAY FEET CENT ‘IG/L INC4-IES MICPOMH() SD M4/L MG/L M(3/L M(,/L P MG/L P
72/06/02 07 05 0000 18.1 46 iorc 0.090 0. O PI) 0.023 0.011
07 05 0003 1g.’ 7.6 64) ( ‘.10 101< 0.060 (J.033 0.023 0.0 13
7?/08/OS 10 35 0000 61 6.20 101< 0.100 0.170 0.0.1 0.022
10 35 0001 22.1
10 35 0004 ? .O 6.4 65 5.20 101< 0.OUO 0.130 0.04i 0.016
72/10/04 17 15 0000 P4 ( .6’) 10t( O.OSO 0.210 0.027 0. 4 )17
17 15 0004 P.! ( -.40 lC ’ 0.050 0.110 0.025 0.015
3?’I 7
DATE TIMF l)EPTH CL ” -fl’L
Fi - (OM OF 4
TO LAY FEET UG/L
7?/Oh/0? 07 05 0000 3.7J
72/ON/OS 10 35 0000 3. OJ
72/10/04 17 15 0000 7.3J
-------
APPENDIX C
TRIBUTARY and WASTEWATER
TREAThENT PLANT DATA
-------
STO ET RETRIEVAL DATE 74/07/02
3302A1 LS3302A1
42 57 30.0 071 56 00.0
CONTOOCOOK RIVER
33003 15 PETERBOROUGH
1/POWDER MILL POND
NH BROG 8,NH SAMPLE SITE 25
I IEPALES 2111204
4 0000 FEET DEPTH
00630 00625 00610 00671 00665
DATE TIME DEPTH N02&N03 TOT KJEL NH3—N PHOS—DIS PHOS-TOT
FROM OF N-TOTAL N TOTAL ORTHO
TO I)AY FEET MG/L MG/L MG/I MG/I P MG/L P
72/08/26 12 45 0.035 0.600 0.015 0.020 0.031
72/09/09 12 10 0.160 0.510 0.081 0.010 0.038
72/11/04 09 00 0.115 0.370 0.126 0.010 0.035
73/03/11 10 10 0.096 0.200 0.048 0.007 0.020
71/03/25 11 30 0.079 0.250 0.034 0.006 0.015
71/04/IS U 45 0.063 0.230 0.030 0.006 0.015
73/04/30 11 00 0.04 0.260 0.027 0.010 0.020
73/05/20 09 00 0.046 0.290 0.025 0.011 0.025
73/06/10 1? 00 0.062 0.690 0.028 0.008 0.035
73/07/07 13 10 0.036 0.460 0.029 0.009 0.035
-------
STORET RETRIEVAL DATE 74/07/02
3302A2 LS3302A2
42 56 30.0 071 57 00.0
CONTOOCOOK RIVER
33 15 PETERBOROUGH
1/POWDER MILL POND
BROG SE OF HANCOCK
11EPALES 2111204
4 0000 FEET DEPTH
00630 00625 00610 00671 00665
DATE TIME DEPTH N02&N03 TOT KJEL NH3-N PHOS—DIS PHOS—TOT
FROM OF N-TOTAL N TOTAL OPIHO
TO DAY FEET HG/L MG/L MG/L HG/L P MG/L P
7.108/26 13 15 0.063 0.400 0.016 0.005K 0.036
7?/O /O9 10 30 0.156 0.500 0.086 0.021 0.037
7?/10/01 11 10 0.190 0.300 0.110 0.015 0.038
72/11/04 09 20 0.120 0.780 0.330 0.007 0.030
71/Q1/06 11 05 0.097 0.320 0.048 0.007 0.015
73/02/11 09 50 0.093 0.720 0.126 0.014 0.015
71/03/11 10 35 0.100 0.280 0.048 0.008 0.020
73/03/25 18 30 0.079 0.320 0.041 0.005K 0.015
73/04/15 10 45 0.067 0.215 0.025 0.006 0.015
73/04/30 11 30 0.048 0.310 0.022 0.011 0.022
73/05/20 13 10 0.042 0.290 0.022 0.010 0.030
73/06/10 12 30 0.052 0.405 0.056 0.006 0.035
71/07/08 10 40 0.036 0.540 0.027 0.007 0.040
-------
STORET RETRIEVAL DATE 74/07/02
3302A3 LS3302A3
42 54 00.0 071 56 30.0
CONTOOCOOI( RIVER
33 15 PFTERBOROUGH
I/POWDER MILL POND
US 202 BROG AT NORTH VILLAGE
I 1EPALES 2111204
4 0000 FEET DEPTH
00630 00625 00610 00671 00665
DATE TIME DEPTH NO2 NO3 TOT KJEL NH3-N PHOS—DIS PHOS-TOT
FROM OF N—TOTAL N TOTAL ORTHO
TO DAY FFF T MG/L MG/L MG/L MG/L P MG/L P
7?/08/2’ 1) 40 0.126 0.600 0.06) 0.028 0.044
7?/09/09 09 40 0.130 0.470 0.078 0.019 0.039
72/10/01 10 55 0.220 0.600 0.132 0.027 0.054
72/11/04 10 30 0.117 0.400 0.132 0.018 0.038
73/01/06 10 35 0.100 0.290 0.054 0.009 0.015
71/02/Il 0 40 0.087 0.240 0.032 0.005K 0.010
73’03/11 10 50 0.097 0.390 0.056 0.007 0.015
71/03/25 13 10 0.078 0.180 0.036 0.005K 0.015
73/04/15 10 25 0.066 0.180 0.015 0.006 0.015
71/04/30 10 30 0.048 0.270 0.020 0.008 0.020
73/05/20 13 10 0.042 0.290 0.014 0.007 0.020
71/06/10 12 15 0.056 0.460 0.037 0.007 0.035
71/07/08 10 50 0.030 0.560 0.016 0.006 0.040
-------
STORET RETRIEVAL DATE 74/07/02
3302A4 LS3302A4
42 50 00.0 071 59 00.0
CONTOOCOOP( RIVER
33 15 PETERBOROUGH
I/POWDER MILL POND
ON US202 AT HADLEY BELO JAFFREY STP
1IEPALES 2111204
4 0000 FEET DEPTH
00630 00625 00610 00671 00665
DATE TIME DEPTH N02&N03 TOT KJEL NH3—N PHOS—DIS PHOS—TOT
FROM OF N-TOTAL N TOTAL ORTHO
TO DAY FEET MG/L MG/L MG/L MG/L P MG/L P
72/08/26 14 30 0.061 0.600 0.088 0.084 0.130
72/Og/Oc 09 50 0.156 1.180 0.260 0.084 0.160
12/10/01 10 30 0.221 1.550 0.810 0.350 0.540
7/i1/0’. 09 30 0.143 0.790 0.378 0.063 0.150
73/01/06 10 05 0.110 0.480 0.140 0.021 0.030
73/02/11 09 17 0.138 0.390 0.130 0.024 0.035
73/03/11 11 45 0.132 0.480 0.120 0.019 0.030
73/03/25 13 00 0.088 0.210 0.072 0.011 0.025
73/04/15 10 05 0.056 0.340 0.038 0.009 0.025
73/04/30 12 30 0.036 0.290 0.032 0.019 0.035
73/05/20 12 45 0.040 0.400 0.054 0.018 0.045
73/06/10 12 00 0.038 0.690 0.073 0.038 0.090
73/07/08 11 15 0.044 0.610 0.063 0.032 0.065
-------
STORET RETRIEVAL DATE 74/07/02
3302A5 LS3302A5
42 49 00.0 072 00 30.0
CONTOOCOOK RIVER
33 15 PIONADNOCK
I/POWDER HILL POND
DOWNSTREAM END OF CHESHIP E POND
1LFPALES 2111204
0000 FEET DEPTH
00630 00625 00610 00671 00665
DATE TIME DEPTH NO?&N03 TOT KJEL NH3—N PHOS—DIS PHOS—TOT
FROM OF N-TOTAL N TOTAL ORTHO
TO DAY FFET MG/L MG/L MG/L MC’/L P MC /L P
7?/08/26 14 45 0.010K 0.400 0.038 0.010 0.023
7?/09/09 09 05 0.073 0.610 0.115 0.010 0.031
7?/1O/O1 10 00 0.091 0.850 0.198 0.007 0.042
73/01/06 09 50 0.092 0.350 0.095 0.005K 0.015
73/02/11 09 11 0.126 0.370 0.050 0.005K 0.010
71/03/11 1 05 0.110 0.260 0.050 0.005K 0.010
73/03/25 12 55 0.075 0.1 0 0.02Q 0.005K 0.0 10
73/04/15 09 50 0.037 0.540 0.017 0.005K 0.010
71/04/30 13 00 0.023 0.400 0.027 0.007 0.020
73/05/20 12 30 0.029 0.290 0.035 0.005K 0.025
73/06/10 12 40 0.025 0.600 0.019 0.005K 0.030
71/07/08 11 25 0.023 0.500 0.026 0.005K 0.030
-------
STORET RETRIEVAL DATE 74/07/02
3302A6 LS3302A6
43 00 00.0 071 55 30.0
CONTOOCOOK RIVER
33 15 HILLSBORO
0/POWDER MILL POND
ST HWY 3! BRDG
I1EPALES 2111204
4 0000 FEET DEPTH
DATE
TIME
DEPTH
NO? .NO3
TOT KJEL
NH3—N
PHOS—DIS
PHOS—TOT
FROM
OF
N—TOTAL
N
TOTAL.
ORTHO
TO
DAY
FEET
MG/L
MG/L
MG/L
MG/L P
MG/L P
7?/08/26
11
45
0.028
0.400
0.028
0.017
0.032
72/09/09
09
20
0.053
0.350
0.092
0.009
0.023
72/10/01
12
50
0.060
0.350
0.097
0.007
0.028
72/11/04
14
00
0.077
0.480
0.092
0.005K
0.030
73/01/06
09
30
0.087
0.290
0.060
0.007
0.015
73/02/11
09
00
0.084
0.170
0.031
0.005K
0.010
73/03/11
09
20
0.093
0.250
0.050
0.007
0.015
73/03/25
12
30
0.066
0.140
0.028
0.005K
0.015
73/04/15
11
15
0.048
0.960
0.017
0.015
73/04/30
11
50
0.046
0.290
0.020
0.010
0.020
73/05/20
11
00
0.039
0.280
0.018
0.006
0.020
73/06/10
13
05
0.026
0.360
0.018
0.005K
0.025
73/07/07
13
45
0.034
0.420
0.024
0.007
-------
STORET RETRIEVAL DATE 74/07/02
330281 LS3302B1
42 58 30.0 071 56 30.0
MOOSE RROOK
33 15 PETERBOROUGH
T/POwDER MILL POND
BPDG AT ELMWOOD
1IEPALES
2111204
0000 FEET DEPTH
00630
00625
00610
00671
00665
DATE
TIME
DEPTH
NO? .NO3
TOT KJEL
1H3-N
PHOS—DIS
PHOS-TOT
FROM
OF
N—TOTAL
N
TOTAL
ORTh4O
TO
DAY
FEET
MG/L
MG/L
MG/I
MG/L P
MG/L P
72/08/26
12
30
0.076
0.300
0.0’S
0.005K
0.022
7?/G9/0
11
?3
0.063
0.300
0.096
0.016
0.019
7?/10/01
11
21
0.059
0.250
0.080
0.005K
0.018
72/11/06
ii
05
0.03?
0.400
0.115
0.005K
0.013
71/03/11
09
45
0.034
0.270
0.017
0.00 5K
0.005K
73/03/25
11
45
0.021
0.220
0.025
0.005K
0.00 5K
71/04/15
1?
00
0.018
0.130
0.006
0.005K
0.00 5K
71/04/30
10
45
0.012
0.230
0.016
0.005K
0.010
71/05/20
09
30
0.010K
0.250
0.007
0.005K
0.010
71/06/10
12
50
0.0?6
0.360
0.015
0.005K
0.020
73/07/07
13
30
0.031
0.420
0.020
0.005K
0.020
-------
STORET RETRIEVAL DATE 74/07/02
3302C1 LS3302C1
42 59 30.0 071 55 30.0
NO NAME
33 15 PETERBOROUGH
0/POWDER MILL POND
NH SAMPLE SITE 248
1 1E ALES
4
00630
00625
00610
00671
00665
DATE
TIME
DEPTH
N02&N03
TOT KJEL
NH3—N
PHOS—DIS
PHOS—TOT
FROM
OF
N-TOTAL
N
TOTAL
ORTHO
TO
DAY
FEET
HG/L
MG/L
HG/L
MG/L P
MG/L P
2111204
0000 FEET DEPTH
7?/O8/26
12
05
0.075
0.200
0.042
0.005K
0.009
72/09/09
10
04
0.067
0.100K
0.038
0.006
0.010
72/10/01
12
15
0.042
0.100K
0.058
0.005K
0.008
72/11/04
10
30
0.033
0.210
0.078
0.005K
0.006
73/02/11
09
15
0.069
0.100K
0.010
0.005K
0.005K
73/03/11
09
00
0.056
0.220
0.027
0.005K
0.005K
73/03/25
12
15
0.048
0.180
0.019
0.005K
0.00 5K
73/04/15
11
00
0.060
0.420
0.007
0.005K
0.005K
73/04/30
11
45
0.036
0.100K
0.012
0.006
0.010
73/05/20
10
00
0.029
0.150
0.007
0.005K
0.005K
73/06/10
13
20
0.044
0.100K
0.010
0.005K
0.015
73/07/07
14
10
0.054
0.330
0.018
0.005K
0.025
-------
STORET RETRIEVAL DATE 74/07/02
330201 LS3302D1
42 54 00.0 071 56 30.0
NO NAME
33 15 PETERBOROUGH
I/POWDER MILL POND
US BPDG AT NORTH VILLAGE
11E ALES 2111204
4 0000 FEET DEPTH
00630 00625 00610 00671 00665
DATE TIME DEPTH NO?&N03 TOT KJEL NH3—N PHOS-DIS PHOS—TOT
FROM OF N—TOTAL N TOTAL ORTI-40
TO DAY FEET MG/L MG/I MG/L Mc./L P MG/L P
72/08/26 13 45 0.119 0.300 0.032 0.046 0.058
72/09/09 09 30 0.130 0.400 0.073 0.019 0.044
72/11/04 10 20 0.100 0.340 0.126 0.018 0.038
71/01/06 10 40 0.095 0.330 0.071 0.008 0.020
73/02/11 09 35 0.088 0.290 0.040 0.00 5K 0.012
71/01/11 10 40 0.189 0.310 0.072 0.005K 0.015
73/03/25 13 15 0.075 0.170 0.035 0.005K 0.015
71/04/15 10 20 0.065 0.250 0.018 0.006 0.015
71/04/30 10 30 0.048 0.500 0.036 0.008 0.020
73/05/20 13 00 0.042 0.340 0.011 0.005K 0.020
73/06/10 12 10 0.050 0.380 0.024 0.007 0.035
73/07/08 11 00 0.030 0.560 0.018 0.005K 0.045
-------
STORET RETRIEVAL DATE 74/07/02
330250 P0330250 P001200
42 49 00.0 07? 01 30.0
JAFFREY
33003 15 MONODNOCK
1/POWDER HILL POND
CONTOOCOOK RIVER
I1EPALES 2141204
4 0000 FEET DEPTH
00630 00625 00610 00671 0066 50051 50053
DATE TIME DEPTH N02&N03 TOT KJEL NH3—N PHOS—DIS PHOS—TOT FLOW CONDUIT
FROM OF N-TOTAL N TOTAL ORTHO RATE FLOW—MGD
TO DAY FEET MG/L MG/L MG/L P4G/L P MG/L P INST MGD MONTHLY
73/10/03 08 00 0.340 9.800 2.450 3.900 4.500
73/10/14 07 00
CP(T)— 0.400 15.500 2.510 4.100 6.000 0.021 0.230
73/10/14 18 00
74/02/13 09 00
CP(T)— 0.080 8.400 4.700 2.800 3.100 0.252 0.288
74/02/13 13 00
74/03/11 07 00
CP(T)— 0.040 9.800 0.083 0.050K 3.100 0.450 0.325
74/03/11 18 00
74/04/30 07 00
CP(T)— 0.160 7.600 1.800 1.900 2.900 1.440 1.800
74/04/30 19 00
-------
STORET RETRIEVAL I)AIF 74/07/02
330251 N 033025 1
‘.2 52 00.0 07? 57 00.0
PETENBOPO
33 15 PETER O OUGH
T/ . OWD N MILL POND
CONTOOCOOi( RIVER
I IEPALES
4
P000100
2141204
0000 FEET DEPTH
00630
006?S
00610
00671
00665
50051
50053
DATE
TIME
DEPTH
NO? NO3
TOT KJEL
NH3-N
PHOS—DIS
PHOS—TOT
FLOW
CONDUIT
FROM
OF
N—TOTAL
N
TOTAL
OPTrIO
RATE
FLO —MGD
TO
DAY
FEET
W/L
IG/L
Mc,/1
M(/L P
MG/I P
INST MGI)
MONTHLY
72/12/04
0 00
0.120
3.100
0.096
1.075
1.440
0.179
0.278
71/01/01
09 00
0.0’ 7
4.500
2.000
1.R00
2.100
0.472
0.275
71/0 /0I
11 00
0.110
11.000
7.950
1.040
3.400
0.251
0.588
71/03/01
08 00
0.123
13.000
9.400
3.800
3.900
0.35’.
0.565
71/05/0?
OR 30
0.710
7.100
).845
2.500
0.264
0.302
73/07/0?
11 00
0.320
1.890
0.190
0.500
0.244
71/OH/01
09 00
0.090
2.700
0.420
?.100
2.700
0.216
0.197
71/12/03
09 30
0.2Y0
p.400
5.000
3.900
4.400
0.085
0.095
71/)?/11
08 00
0.240
12.500
5.600
5.300
6.200
0.501
0.250
76/0 /01
OB 30
0.040
1.000
0.170
6.000
6.800
0.359
0.402
74/01/11
0. 00
0.040
12.000
0.210
0.1?0
6.600
0.140
0.199
7’,/0’e/01
08 00
0.240
13.000
6.200
3.900
4.900
0.134
0.135
74/05/03
10 00
0.320
14.000
8.000
5.000
5.300
0.357
0.275
-------
APPENDIX D
JAFFREY and PETERBOROUGH
PHOSPHORUS LOADS
-------
JAFFREY and PETERBOROUGH
PHOSPHORUS LOADS
In the initial analysis of the phosphorus regime of the Powder Mill
Pond drainage, it became obvious that there was more than the expected
degree of entrapment of phosphorus in the Contookcook River. On Map 2,
following, the phosphorus loads calculated for each of the tributary
sampling sites (flows adjusted) are shown. It will be noted that there
was a progressive decline in loads from station A-4 (below the Jaffrey
outfall) to the Pond inlet at A-2 (about 14 stream miles) because of
sedimentation and/or biological assimilation in impoundments along the
river as at Noone, in Peterborough, and at North Village, as well as
sedimentation in the river itself, as between A-3 and A-2.
Because of these losses in the system, it was necessary to calcu-
late the phosphorus contributions from Jaffrey and Peterborough indirectly
(the phosphorus loads from these two sources, collectively, were greater
at the points of discharge than the entire phosphorus load measured at
A-2), and the following rationale was used to estimate the phosphorus
loads reaching Powder Mill Pond:
1. The mean P load of 2 B-l and C-l (both without point
sources) = 35.5 lbs/mi /yr;
2. 35.5 x 108.4 mi 2 (area of Contoocook River drainage
at A-2) = 3,850 lbs P/yr due to non-point sources;
3. Then 9,450 lbs (P load measured at A—2) - 3,850 lbs =
5,600 lbs P/yr attributable to the two point sources.
4. The combined phosphorus loads measured at Jaffrey
(6,030 lbs) and Peterborough (3,860 ibs) - 9,890 lbs,
-------
so
Jaffrey = x 5,600 = 3,410 lbs/yr (rounded),
or 31.6% of the total load; and Peterborough =
x 5,600 = 2,190 ibs/yr, or 20.3% of the total
phosphoru load reaching station A-2.
------- |