DWQ-2008-020005

MANNING MEADOWS RESERVOIR

LIMNOLOGICAL ASSESSMENT OF WATER QUALITY

March 2008

1
Manning Meadows Reservoir Report
March 6, 2008

Manning Meadows Reservoir is listed by the State of Utah as an impaired water body
because dissolved oxygen and total phosphorus does not meet State water quality
standards. In partnership with Utah Division of Water Quality (UDWQ), personnel of
the Fishlake National Forest (WCNF) collected data from Manning Meadows Reservoir
from March 2006 to October 2006 to provide recent detailed water quality information to
support a Total Maximum Daily Load (TMDL) analysis. This report contains
information listed below.
• Sections 1.0 and 2.0: Description of the water body and associated watershed, the
nature of the impairment; water quality standards of the parameters of concern for
the water body.
• Section 3.0: Discussion of whether the impairments are naturally occurring and,
if not, what water body targets and endpoints should be recommended.
• Section 4.0: Discussion of which land management activities are contributing to
the impairment, what practices may be recommended to reduce sources of
impairment, and an estimate of the acceptable load or the degree to which the
current pollutants (loads) need to be decreased to attain the defined endpoints.
• Section 5.0: Identification of significant pollutant sources through use of existing
information (maps, reports, inventories, and analyses) and new data.
• Section 6.0: Description of water quality data in relationship to abiotic and
biological processes.
• Section 7.0: All sources contributing to impairment will be evaluated and a
determination of beneficial use support will be presented.
• Section 8.0: The rationale for addressing all sources and causes that are
significant for the attainment of water quality targets.
2

Figure 1. Manning Meadows Reservoir
Figure 2. Approximate Location of Manning Meadows Reservoir
3
1.0 Introduction

Manning Meadow Reservoir is an impoundment of a high mountain meadow by an
earthen dam. The reservoir has a surface area of 59 acres, volume of 996 acre-feet, and a
mean depth of 5.5 meters. It is located at an elevation of 9,750 feet above mean sea level
on the Fishlake National Forest in Piute County on the Sevier Plateau. The watershed
area is 1,186 acres (Judd 1997).

Surface inflows to the reservoir consist primarily of Manning Creek and Timber Creek.
Manning Creek is located in a meadow that extends upstream from the reservoir in a
small valley, filled with sedges and grasses. Manning Creek above the reservoir is a
large bog where water spreads and flows slowly. Water quality samples were collected
from a 0.3 feet (4”) deep pool where it was clear, although the bottom of the pool was
covered with silt. The bog area is 400’ wide and the area where water is the deepest, up to
0.3 feet deep, is 25 feet wide. The creek is not aggrading or degrading. The average
gradient of the meadow above the reservoir is 1.9 percent (Judd 1997). When water
quality samples were taken, water in Timber Creek was about one foot wide and 0.1 feet
deep. The Timber Creek water quality sample site is located above the dirt road and
above the Utah Division of Wildlife Resources trout egg collect station that is on Timber
Creek.

The watershed above the reservoir is 1,186 acres in size. The watershed receives 25 to 30
inches of precipitation annually with a frost-free season of 20-40 days. Most of the
precipitation occurs in the form of snow that falls during the winter. The soil is of
volcanic origin and has moderate permeability and moderately slow erosion and runoff.
Phosphorus occurs naturally from the volcanic geology of the watershed and the volcanic
soils can have high concentrations of inorganic phosphorus. The immediate area around
the reservoir is sagebrush-grass with aspen and conifer forest growing on the slopes
surrounding the valley bottom. The reservoir is in an area of high, rolling ridges and
valleys characteristic of the Sevier Plateau (Judd 1997).

Several land uses occur within the watershed draining into the reservoir. The only
recreational facility at the reservoir is one toilet, and the area offers itself to primitive
camping. There are no Forest Service campgrounds in the area. A Utah Division of
Wildlife Resources trout egg collect station is located on Timber Creek between the
reservoir and the dirt road next to the reservoir. At the egg collection station, there is a
bare parking pad for two vehicles and the egg collection site in the stream is made of
concrete. People launch their boats into the reservoir from a two-track path leading to the
reservoir edge near the dam. Some dispersed recreation sites are located west of the dam
near this area. The shoreline around the reservoir is owned and managed by the Forest
Service with unlimited public access. Private land makes up 312 acres or 29% of the
drainage area, and Forest Service land makes up 774 acres or 71% of the drainage area.
Other land uses include private summer home recreation, cattle and sheep livestock
grazing, snowmobiling, backpacking, camping, and hunting and fishing. Usage is light
except during the hunting season.

4
Most of the ground cover in the watershed above the reservoir is in good condition. An
88 acre slope above the reservoir was burned several years ago but the area has recovered
and no accelerated erosion is occurring at the present time. The dirt road that is on the
west side of the reservoir has proper drainage structures and is maintained by the county.
On private land near the summer homes, some ruts in the road tend to pool water. The
shore surrounding the reservoir has dense vegetation in most areas.

2.0. Water Quality Standards

This section discusses the associated impairment and parameters of concern with respect
to state water quality standards, antidegradation policies and designated beneficial uses
for Manning Meadow Reservoir.

The State of Utah has designated the waters within the reservoir as Antidegradation
Segments indicating that the existing water quality is better than the established standards
for the designated beneficial uses. Water quality is required by state regulation to be
maintained at this level. The beneficial uses of streams within the Forest, as designated
by the Utah Department of Environmental Quality, Division of Water Quality, are Class
2B – protected for recreation; Class 3A – protected for cold water species of game fish
and other cold water aquatic species; and Class 4 – protected for agricultural uses (Utah,
State of 2005).

Manning Meadow Reservoir is listed as impaired for dissolved oxygen and total
phosphorus for Cold Water Species of Game Fish (Beneficial Use Class 3A). The
methodology for listing these parameters are described below.

Listing methodology for Dissolved Oxygen
The listing methodology employed by Utah to assess Class 3A (aquatic life) beneficial
use for dissolved oxygen (DO) involves evaluating the reservoir profile data collected at
the surface and at one meter intervals to determine the percentage of the water column
that falls below the one day average value of 4.0 milligrams per liter (mg/L). For
stratified lakes, the beneficial use is supported if the dissolved oxygen concentrations are
greater than the dissolved oxygen standard in at least 50% of the water column depth. For
non-stratified lakes, the beneficial use is supported if at least 90% of the oxygen
measurements are greater than the dissolved oxygen standard for the entire water column
depth. (Utah, State of 2007).

5

In addition, an evaluation of the trophic state index (TSI), winter dissolved oxygen
conditions with reported fish kills, and the presence of significant blue green algal species
in the phytoplankton community is made. If two of these three additional criteria indicate
a problem, the support status can be shifted downward.

Lastly, the historical beneficial use support is evaluated for the water body in question. If
a waterbody shows that beneficial use impairment consistently exists, the waterbody
should be listed on the 303(d) list. However, if a waterbody exhibits a mixture of
partially and fully supporting conditions over a period of years, the waterbody should
continue to be evaluated.

Listing Methodology for Total Phosphorus
Total phosphorus does not directly affect aquatic life, but as a nutrient it can stimulate
growth of aquatic algae and emergent plants. Nuisance blooms of algae and other aquatic
plants can have a negative effect on the amount of dissolved oxygen and habitat for fish
and their food supply (macroinvertebrates). The assessment methodology employed by
Utah for total phosphorus is; a waterbody needs further study if more than 10% of the
phosphorus measurements at the surface, above the thermocline, below the thermocline
and at the bottom exceed 0.025 mg/l. If further study is needed, other factors such as fish
kills, low dissolved oxygen, blue-green algae dominance, and the Trophic State Index
(TSI) are considered in the evaluation.

An assessment of the water quality conditions in Manning Meadow Reservoir in 1997
(Judd 1997) is described below.

The water quality of Manning Meadow Reservoir is good. It is considered to be soft with a hardness
concentration value of approximately 31 mg/L (CaCO3). The only parameters that have exceeded
State water quality standards for defined beneficial uses are phosphorus and dissolved oxygen. The
average concentration of total phosphorus in the water column in 1992 was 113 ug/L which exceeds
the recommended pollution indicator for phosphorus of 25 ug/L. Phosphorus concentration in the
hypolimnion have been as high as 396 ug/L and during August 5, 1992 averaged 163 ug/L. These high
concentrations of nutrients lead to the production of algal blooms. Such a high amount of production
can lead to anoxic problems in the water column. As depicted in the August 5, 1992 profile these types
of conditions manifest themselves. The reservoir is stratified at the 4 meter depth and below that the
dissolved oxygen concentrations decline rapidly to a low of 0.5 ug/L near the bottom of the reservoir.
Dissolved oxygen concentrations in late summer and winter substantiate the fact that water quality
impairments do exist. These conditions are deleterious to the fishery, rendering large portions of the
Table 1. Utah’s Dissolved Oxygen Criteria for Class 3A waters (R317-2; Standards
of Quality for Waters of the State).
Timeframe Minimum
Dissolved
Oxygen
Explanations
30 day average 6.5 mg/l
7 day average 9.5/5.0
mg/l
Not to exceed 110% of saturation. 9.5 when early life
stages are present. 5.0 when all other life stages present
1 day average 8.0/4.0
mg/l
Not to exceed 110% of saturation. 8.0 when early life
stages are present. 4.0 when all other life stages present
6
water column unsuitable for a fishery. In addition dissolved oxygen concentrations may reach critical
state during the winter period for fish.

Current data suggest that the reservoir is a nitrogen limited system. TSI values indicate that the
reservoir is highly productive and classified as a eutrophic system. According to DWR no fish kills
have been reported in recent years. The reservoir supports populations of splake, a cross of brook trout
(Salvelinus fontinalis) with lake trout (Salvelinus namaycush), and Bonneville cutthroat trout
(Oncorhynchus clarki utah). DWR maintains a breeding population of these cutthroat trout in the
reservoir. The lake was treated for rough fish competition in 1989 so that management of the fishery
for these fish could occur. According to recent stocking records, advanced fingerling Bonneville
cutthroat trout and Splake (male brook trout X female lake trout) (Salvelinus fontinalis male X
Salvelinus namaycush female) continue to be stocked in the reservoir. The flora is fairly typical, but
not particularly diverse. The dominance of blue- green algae and diatoms indicates that the lake has
fairly good water quality with eutrophic conditions present in the reservoir.

Pollution Assessment
The nonpoint sources of pollution in Manning Meadows Reservoir is sedimentation and nutrient
loading from grazing, and travel routes in the watershed and in the vicinity of the reservoir. Grazing
activity is extensive and is contributing to the nutrient load as indicated by the reservoir response in
recent years. The grazing allotment is in the Manning Creek Allotment. There are no point pollution
sources in the watershed.

Water quality data collected since 1997 indicate that the assessment described above is an
accurate description of water quality conditions in Manning Meadow Reservoir. As seen
in Figure 3, 3 of 13 (23%) profiles fully meet State standards of 50% of the profile
supporting 4 mg/l DO. In 2006, none of the profiles met this standard. As shown in
Figure 4, most of the total phosphorus as P values exceeds the State indicator value. The
total phosphorus exceedances (greater than 0.025 mg/l) from 1992 through 2005 are 47 of
60 samples (78.3%) and in 2006 are 17 of 19 samples (89.5%).

3.0 Water Quality Targets/Endpoints

This section discusses whether the impairments are naturally occurring and if not, what
quantifiable targets or endpoints will achieve water quality standards.

A review of potential pollution sources have identified a few that may be contributing to
elevated total phosphorus and may result in dissolved oxygen deficits in the reservoir.
These are discussed in Sections 4.0 and 5.0. The recommended endpoints for Manning
Meadow Reservoir are mean in-lake concentrations of total phosphorus of less than 0.025
mg/l, and dissolved oxygen concentrations above 4.0 mg/l in greater than 50% of the
water column.

4.0 TMDL

Figure 3. Manning Meadows Reservoir -
Percent of Water Column Supporting 4 mg/l D.O. Criteria
47
33
54
38
62
23 29
54
8
46
31 31
42
0
10
20
30
40
50
60
70
80
90
100
6/20/2000
8/16/2 000
6/19/200 2
8/28/2002
6/8/2004
7/21/2004
8/11/2004
9/8/2004
3/14/2 006
6/26/200 6
7/25/2006
8/21/2006
9/15/2006
Date
%
D
.
O
.

>
4
.
0

m
7

This section discusses which land management activities are contributing to the
impairment, practices recommended to reduce sources of impairment, and an estimate of
the acceptable load or the degree to which the current pollutants (loads) need to be
decreased to attain the defined endpoints.

Most of the total phosphorus in the Timber Creek drainage is in the dissolved fraction
indicating natural spring sources for total phosphorus and not soil disturbance.
Recommended practices to reduce sources of phosphorus loading from Manning Creek
are:
• On private land, consolidate specific ATV and truck routes in the watershed
draining into Manning Creek and tributaries in order to reduce the numerous trails
and routes, some of which cross Manning Creek and the southern tributary of
Manning Creek. Avoid wet areas and avoid crossing Manning Creek or use small
bridges to cross. Move cattle frequently to keep livestock from congregating and
denuding vegetation in the upland and spring areas.
• On National Forest lands, maintain the fence that keeps livestock out of the
wetland area of Manning Creek just above the reservoir. Designate areas where
dispersed camping should occur and control soil erosion from these areas. Limit
vehicle access to the reservoir to one boat launch and create proper drainage for
this route to control erosion and sediment transport. Where soil erosion appears to
be causing sediment to enter the reservoir, use best management practices to
control erosion such as planting grasses and mulching bare soil areas, and placing
barriers such as branches and rocks in unwanted paths.

Figure 4. Total Phosphorus as P - Manning Meadows
Reservoir
0.000
0.050
0.100
0.150
0.200
0.250
0.300
0.350
0.400
0.450
Jun-92
Aug-92
Jul-94
Aug-94
Mar-95
Jul-96
Aug-96
Jul-98
Sep-98
Jun-00
Aug-00
Jun-02
Aug-02
Jun-04
Jul-04
Aug-04
Sep-04
Mar-06
Apr-06
May-06
Jun-06
Jul-06
Aug-06
Sep-06
Date
T
P

(
m
g
/
21: Surface
23: 1 meter
above
thermocline
27: 1 meter
below
thermocline
29: 1 meter
from bottom
Average

8
It is anticipated that these practices will reduce the anthropogenic load of total
phosphorus in the reservoir but additional monitoring will be required to determine if and
when water quality endpoints are met.

5.0 Significant Sources

The primary anthropogenic sources of phosphorus entering the reservoir are from a few
areas on private land and National Forest land which are listed below.
• On private land, numerous trails and routes caused by trucks and ATVs, some of
which cross Manning Creek and the southern tributary of Manning Creek. Few
bare spots in the upland and in spring areas caused by trampling and over-grazing
by livestock and wildlife.
• On National Forest land, bare soil along two-track path leading to the reservoir
that is used as a boat launch and dispersed camping sites near dam.

6.0 Technical Analysis

This section contains a description of water quality data conditions at Manning Meadow
Reservoir, a discussion containing a summary by Bronmark and Hansson (2005) of
abiotic and biological processes that occur in lakes and ponds, and a comparison of these
concepts with the water quality conditions of Manning Meadow Reservoir.

Trophic State – Carlson’s Trophic State Index (TSI) is used to determine the biological
productivity of a lake using three indicators, chlorophyll a (indicative of the amount of
algae), secchi depth (indicative of water clarity) and total phosphorus (a critical nutrient
for algae growth). The TSI for a lake is determined using regression equations and
values for chlorophyll a, secchi depth, and total phosphorus. Carlson states that the best
parameter to use for the index is chlorophyll a and transparency should be used only if no
other parameter is available (Kent State 2005).

Carlson’s TSI values classify northern temperate lakes into three general categories,
oligotrophy, mesotrophy and eutrophy. Oligotrophic lakes are characterized by clear
water and oxygen throughout the year in the hypolimnion (bottom water layer in a lake.
Mesotrophic lakes are characterized by moderately clear water and an increasing
probability of hypolimnetic anoxia (low DO) during summer. Eutrophic lakes are
characterized by anoxic hypolimnia and macrophyte problems (Kent State 2005).

Based on water sampling of Manning Meadow Reservoir in 2006 and 2007, the trophic
state index of chlorophyll-a during the winter and early summer is mainly mesotrophic.
The trophic state index for secchi depth reflects a similar pattern but indicates a more
eutrophic state and gave values that were between upper oligotrophic and eutrophic.
Trophic state based on total phosphorus was consistently eutrophic.

9

Lake Morphology – Manning Meadow Reservoir is somewhat tear-drop in shape and is
about 800 feet wide, 5,000 feet long, and has a mean depth of 18.1 feet (5.5 meters).

Temperature – The temperature of Manning Meadow Reservoir ranges in winter from
0ºC at the surface to 3.5ºC at the bottom and in summer from 11.5 to 19.0ºC at the
surface and from 4.2 to 8.5ºC near the bottom at a depth of 13.0 to 14.0 meters. The
temperature profile indicates that the reservoir is stratified during the summer season with
a thermocline occurring between 3 to 7 meters.

Figure 5. Manning Meadows Reservoir: Trophic State Indicies
0
10
20
30
40
50
60
Feb-06 Mar-06 May-06 Jul-06 Aug-06 Oct-06 Nov-06
Date
TS
I

V
a
l
u
Secchi
Chlorophyll A
Total Phosphorous

Figure 6. Manning Meadows Reservoir: Temperature vs. Depth
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
10.0
11.0
12.0
13.0
14.0
15.0
16.0
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0
Temperature (degrees C)
De
p
t
h

(
m
6/20/2000
8/16/2000
6/19/2002
8/28/2002
6/8/2004
7/21/2004
8/11/2004
9/8/2004
3/14/2006
6/26/2006
7/25/2006
8/21/2006
9/15/2006
10
Light (secchi depth) – The secchi depth in Manning Meadow Reservoir in 2006 and
2007 ranged from 1.0 to 7.5 meters with most of the measurements being around 1.5
meters. During the March winter sample of 2006, ice was solid for 0.6 meters and snow
was 1.5 feet deep and lay upon the entire surface of the ice. In April 2006, the ice was
one meter thick and had several layers.

Catchment Area (size of catchment, type of geology) – The watershed draining into
Manning Meadow Reservoir is 1,186 acres in size and is located on the Sevier Plateau
which is within the Southern High Plateaus Section, an extensive unbroken expanse of
extrusive igneous rock. These lava capped plateaus contain flat-lying flows of andesite,
rhyolite, latte, and basalt, together with extensive deposits of volcanic ash and
agglomerate (Stokes 1986). Most of the reservoir is located in a north-south oriented
steep valley that is about 1.5 mile wide at the top and the valley at the upper end of the
reservoir opens up into a broad, 3000 foot-wide, low gradient valley bottom surrounded
by steep mountains about 1000 feet above the valley floor. The predominant vegetation
types in the valley bottom are sagebrush/mountain brush with sedges in the valley floor
wetlands and pockets of aspen and conifer on the steep side slopes. According to
Bronmark and Hansson (2005), a small catchment area, particularly within conifer forest,
is likely to have low nutrients since soils have low productivity and rainwater has a short
distance to reach the lake.

pH – Most of the pH values for water samples collected in Manning Meadow Reservoir
are between 7.3 and 8.5. The only time pH was very high was in surface three meters in
August of 2000 which went above a pH of 10. As seen in Figure 5, pH tends to be
stratified during the summer season particularly in August. The pH of the streams
flowing into the reservoir lies within a range of 7.0 and 8.4. A high reading of 9.4 is
recorded for Timber Creek in September 2006. The pH of the water flowing in Manning
Figure 7. Manning Meadows Reservoir: pH vs. Depth
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
10.0
11.0
12.0
13.0
14.0
15.0
16.0
6.0 6.5 7.0 7.5 8.0 8.5 9.0 9.5 10.0 10.5 11.0
pH
De
p
t
h

(
m
6/20/2000
8/16/2000
6/19/2002
8/28/2002
6/8/2004
7/21/2004
8/11/2004
9/8/2004
3/14/2006
6/26/2006
7/25/2006
8/21/2006
9/15/2006

11
Creek is in the range of 6.9 and 7.8. Manning Meadow Reservoir is alkaline and is typical
of most lakes. According to Bronmark and Hansson (2005), the majority of lakes have a
pH between 6 and 9.

Nutrients – Table 2 contains a summary of exceedances and Table 3 contains the
dissolved and total phosphorus and nitrogen concentrations in Manning Meadow
Reservoir for samples collected since 1992. For samples collected at all depths since
1992, the average concentration of total phosphorus as P at the reservoir’s surface (21) is
0.025 mg/l, above the thermocline (23) is 0.025 mg/l, below the thermocline (27) is 0.083
mg/l, and just above the bottom (29) is 0.191 mg/l. For all samples collected, nitrogen as
dissolved nitrite+nitrate was well below the standard of 4.0 mg/l and most of the samples
(82%) did not detect nitrogen.

Table 2. Summary of Total Phosphorus exceedances and concentrations.

Time
Period
Number of
Exceedances
Number of
Samples
Percent of
Exceedances
Average Concentration
(mg/l)
1992 – 2005 47 60 78.3 0.075
2006 17 19 89.5 0.095
1992 - 2006 64 79 81.0 0.080

It may be inferred from these data two key characteristics of the reservoir. The first
characteristic is the significance of internal nutrient loading into the reservoir
(specifically total phosphorus). Internal nutrient loading is an important factor in
evaluating the causes of water quality impairment as well as in establishing practical
solutions and reasonable timelines for improvement. Internal loading can be shown by
the fact that phosphorus concentrations in samples collected below the thermocline (27
and 29) are all much higher than those collected above the thermocline. The second
characteristic demonstrated by these data is the high proportion of dissolved phosphorus
to total phosphorus. In fact for several samples the data indicate the dissolved portion is
actually higher than the total which is likely due to the small amount of uncertainty
associated with the analytical analysis. The dissolved form of phosphorus typically
originates from biological sources including microbial decomposition. Therefore the
relatively higher concentrations of phosphorus in the lower levels of the reservoir and the
preponderance of phosphorus in the dissolved form indicate that internal nutrient loading
is an important factor contributing to DO impairment in Manning Meadows Reservoir.

12
Table 3. Manning Meadows Reservoir (STORET 5945040) - Nutrients by depth level.
Dissolved Total Phosphorus as P (mg/l) Total Phosphorus as P (mg/l) D-NO2+NO3, N (mg/l)
Date 21 23 27 29 21 23 27 29 Average 21 23 27 29
06/24/1992 0.058 0.045 0.084 0.346 0.037 0.029 0.054 0.396 0.129 0.12 0.20 0.07 ND
08/05/1992 0.019 0.018 0.103 0.187 0.039 0.020 0.106 0.219 0.096 ND ND ND 0.03
07/06/1994 0.062 0.127 0.116 0.038 0.026 0.027 0.045 0.111 0.052 ND ND ND ND
08/23/1994 0.028 0.024 0.129 0.168 0.044 0.033 0.161 0.205 0.111 ND ND ND ND
03/08/1995 --- --- --- --- --- --- --- ND --- --- --- ---
07/01/1996 0.020 0.020 0.030 0.090 0.020 0.020 0.030 0.140 0.053 ND ND ND 0.03
08/21/1996 0.030 0.030 0.060 0.110 0.020 0.020 0.060 0.120 0.055 ND ND 0.02 0.04
07/09/1998 ND ND 0.022 0.048 0.025 0.031 0.025 0.089 0.043 ND ND ND ND
09/08/1998 ND ND 0.077 0.039 0.027 0.023 0.091 0.172 0.078 ND ND ND ND
06/20/2000 0.024 0.022 0.031 0.148 0.028 0.028 0.043 0.330 0.107 ND ND 0.10 ---
08/15/2000 ND ND 0.032 0.056 0.022 0.040 0.023 0.064 0.037 0.10 ND ND 0.10
06/19/2002 0.027 0.038 0.032 0.073 --- --- --- --- ND ND ND ND
08/28/2002 --- 0.032 ND ND 0.046 0.044 0.034 0.062 0.047 ND ND ND ND
06/08/2004 0.026 0.026 0.024 0.026 0.033 0.036 0.027 0.031 0.032 ND ND ND ND
07/21/2004 ND ND 0.077 0.192 ND ND 0.093 0.256 0.175 ND ND ND ND
08/11/2004 ND ND 0.072 0.118 ND ND 0.083 0.145 0.114 ND ND ND ND
09/08/2004 ND 0.020 0.182 0.268 0.026 0.020 0.194 0.323 0.141 ND ND ND ND
03/14/2006 0.033 0.026 0.052 0.199 0.031 0.032 0.073 0.320 0.114 1.00 0.36 0.50 0.24
04/17/2006 Unsafe Ice Conditions - No samples taken
05/30/2006 Unsafe Ice Conditions - No samples taken
06/26/2006 ND 0.022 0.058 0.115 ND 0.020 0.087 0.163 0.090 ND ND ND ND
07/25/2006 ND ND 0.048 0.083 0.026 0.034 0.118 0.172 0.088 ND ND ND ND
08/21/2006 ND ND 0.114 0.248 0.027 0.027 0.167 0.313 0.134 ND ND ND ND
09/15/2006 ND ND 0.052 0.123 0.028 0.025 0.136 --- 0.063 ND ND ND ND
Note: ND means Non-detect. Red highlighted values exceed pollution indicator limit (0.025 mg/l for phosphorus and 4.0 mg/l for NO3+NO2).
13
Dissolved and total phosphorus and nitrogen concentrations in water samples collected in
streams flowing into Manning Meadow Reservoir are shown in Table 4 and those values
that are non-detect or above the State indicator value of 0.05 mg/l are indicated. For
streams above the reservoir, the average concentration of total phosphorus as P is 0.044
mg/l. During the 2006 sampling period, 50% of the samples in Timber Creek are above
the total phosphorus indicator value of 0.05 mg/L. All of the samples collected in
Manning Creek above the reservoir are below the total phosphorus State indicator value.
The ratio of dissolved total phosphorus to total phosphorus indicates that most of the
phosphorus from Timber Creek is in the dissolved fraction and most of the phosphorus in
Manning Creek is from the sediment-born fraction.

Table 4. Nutrient data for streams at Manning Meadow Reservoir.
Location Date
Dissolved
Total
Phosphorus
(mg/l)
Total
Phosphorus
(mg/l)
DP:TP
Ratio
Dissolved
Nitrite +
Nitrate
as N
(mg/l)
Timber Ck above Manning Meadow Res. 07/06/1994 0.067 0.034 1.97 ---
Timber Ck above Manning Meadow Res. 08/21/1996 0.060 0.040 1.50 ---
Timber Ck above Manning Meadow Res. 07/09/1998 0.024 0.034 0.71 ---
Timber Ck above Manning Meadow Res. 09/08/1998 0.035 0.034 1.03 ---
Timber Ck above Manning Meadow Res. 06/20/2000 0.067 0.052 1.29 ND
Timber Ck above Manning Meadow Res. 08/28/2002 ND 0.075 ND
Timber Ck above Manning Meadow Res. 06/08/2004 0.025 0.021 1.19 ND
Timber Ck above Manning Meadow Res. 07/21/2004 0.032 0.035 0.91 ND
Timber Ck above Manning Meadow Res. 08/11/2004 0.035 0.031 1.13 ND
Timber Ck above Manning Meadow Res. 09/08/2004 0.036 0.035 1.03 ND
Timber Ck above Manning Meadow Res. 09/29/2005 ND 0.020 ND
Timber Ck above Manning Meadow Res. 11/16/2005 ND 0.022 ND
Timber Ck above Manning Meadow Res. 03/14/2006 No Access to Water
Timber Ck above Manning Meadow Res. 04/17/2006 No Access to Water
Timber Ck above Manning Meadow Res. 05/30/2006 ND 0.023 ND
Timber Ck above Manning Meadow Res. 06/26/2006 0.028 0.233 0.12 ND
Timber Ck above Manning Meadow Res. 07/25/2006 ND 0.030 ND
Timber Ck above Manning Meadow Res. 08/21/2006 0.035 0.050 0.70 ND
Timber Ck above Manning Meadow Res. 09/15/2006 0.049 0.066 0.74 ND
Timber Ck above Manning Meadow Res. 10/03/2006 0.031 0.028 1.11 ND

Manning Ck above Manning Meadow Res. 03/14/2006 No Access to Water
Manning Ck above Manning Meadow Res. 04/17/2006 No Access to Water
Manning Ck above Manning Meadow Res. 05/30/2006 ND ND ND
Manning Ck above Manning Meadow Res. 06/26/2006 ND ND ND
Manning Ck above Manning Meadow Res. 07/25/2006 ND 0.047 ND
Manning Ck above Manning Meadow Res. 08/21/2006 Not enough water to take readings or sample.
Manning Ck above Manning Meadow Res. 09/15/2006 ND 0.040 ND
Manning Ck above Manning Meadow Res. 10/03/2006 ND 0.023 ND

Note: ND means Non-detect. Red highlighted values exceed pollution indicator limit (0.05 mg/l for phosphorus
and 4.0 mg/l for NO3+NO2).

14
Oxygen –The dissolved oxygen profiles for Manning Meadow Reservoir shows
stratification occurring throughout the year. Dissolved oxygen is above the State standard
of 4.0 mg/l between the surface and 4 to 8 meters in depth and the dissolved oxygen
drops rapidly at 3 to 5 meters from the surface. The March 2006 profile is an exception
and has dissolved oxygen below State standards throughout almost the entire water
column.

For all the sample events since 2000, 61 percent of the samples at 1.0 -meter intervals in
the water column were below the dissolved oxygen standard of 4.0 mg/l. For the profiles
measured in 2006, 66 percent of the samples at 1.0-meter intervals in the water column
were below 4.0 mg/l.

Macrophytes – During sampling in 2006, macrophytes were seen in the shallow water of
the reservoir near the Manning Creek inlet. Macrophytes were not seen in other areas of
the reservoir, probably because the reservoir was too deep and light cannot penetrate very
far into the water making it difficult for macrophytes to grow.
Macrophytes and algae are the only aquatic organisms that need light as their energy
source. Since light intensity decreases with depth, the depth at which macrophytes grow
is dependent upon the amount of light that penetrates through the water. Angiosperms
need about 15% of the amount of light at the surface (Bronmark and Hansson 2005).
Manning Meadows Reservoir has an average depth of 5.5 meters and a maximum depth
of 19 meters. Much of the reservoir bottom would not be conducive for macrophyte
growth based on the relationship between secchi depth and maximum depth of growth of
angiosperms shown by Chambers and Kaiff (1985) and Bronmark and Hansson (2005).
The relationship indicates that with a secchi depth of 1.5 meters the maximum depth of
Figure 7. Manning Meadows Reservoir: Dissolved Oxygen vs. Depth
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
10.0
11.0
12.0
13.0
14.0
15.0
16.0
0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0
D.O. (mg/l)
De
p
t
h

(
m 6/20/2000
8/16/2000
6/19/2002
8/28/2002
6/8/2004
7/21/2004
8/11/2004
9/8/2004
3/14/2006
6/26/2006
7/25/2006
8/21/2006
9/15/2006

15
angiosperm growth would be less than 3 meters. However, plants can overcome the depth
limitation by growing tall and reaching light near the surface while the roots are in the
lake bottom below the area of minimum light requirements (Bronmark and Hansson
2005).

Algae –During the 2006 and 2007 sampling events, chlorophyll a, uncorrected for
pheophytin ranged from 2.4 to 8.5 ug/l with the largest value in August and the lowest
value in March. A seasonal trend is observed in the data where algae concentrations are
much less during the winter and increases as water temperatures rise in the summer.
While sampling in July and August 2006, a heavy algae bloom that looked green and
mossy with particles in it, was seen in Manning Meadows Reservoir.

A taxonomic survey of phytoplankton was conducted on Manning Meadow Reservoir
from a sample of the water column collected in August 2006. The results of this sample
compared to those in the Judd inventory (1997) is presented in Table 5.

Table 5. Diversity measurements for Manning Meadows Reservoir.
Diversity Measure Judd (1997) 2006 Sample
Shannon-Weaver Index 0.28 1.10
Species Evenness 0.16 0.48
Species Richness 0.20 1.65

According to these measurements the phytoplankton community in Manning Meadow
Reservoir has increased in diversity and richness over the 10 years between sampling
events although this could also be attributable to the time of year the samples were
collected. As the summer growing season progresses the assemblage of phytoplankton
changes in response to climactic variables and competition between species. The
community can shift from relatively diverse to only a few species in a short period of
time in response to an algal bloom. Therefore these data may not be truly reflective of
environmental changes in the reservoir.

Discussion – Pollution from point sources and nonpoint sources can enter a lake and
cause water quality problems (Olem and Flock 1990, 94). Non-point sources of pollution
can contaminate lakes through runoff and groundwater. Runoff can carry sediment and
fertilizers from roads, lawns, and agricultural wastes such as livestock manure. Nutrients
and bacteria can enter a lake through malfunctioning septic systems. When bacteria
consume nutrients, dissolved oxygen is consumed, particularly in the hypolimnetic zone.
This can result in low dissolved oxygen levels, fish kills, odors, and noxious conditions.
In addition, nutrients act as a fertilizer and can stimulate excessive growth of algae and
macrophytes that may contribute to additional loss of dissolved oxygen.

A review of the potential point source and nonpoint source pollution within the watershed
draining into Manning Meadow Reservoir indicates that there are no point sources of
pollution. Non-point sources of pollution include livestock and wildlife grazing in the
watershed and from some limited areas of soil disturbance. There is some soil disturbance
by livestock and wildlife in the meadow above the reservoir. No grazing appears to be
16
occurring in the boggy area of Manning Creek just above the reservoir and a wire fence is
in place to keep livestock out. Sedimentation of Manning Creek is evident by the silt that
is deposited in the boggy area. The source of the silt may be from several sources in the
watershed draining into Manning Creek above the reservoir. For the most part, the
swale/channel in Manning Creek meadow above the reservoir appears to be fairly stable
with occasional bare soil. Possible sediment sources that are located on private land
include:
• Numerous trails and routes caused by trucks and ATVs some of which cross
Manning Creek and the southern tributary of Manning Creek.
• Few bare spots in the upland and a few bare spots in spring areas caused by
wildlife and livestock.

No sources of pollution were identified from Timber Creek and the egg collection station
appears to be functioning well and not contributing sediment to the stream. A parking pad
near the egg collection station consisting of two parking spaces is on relatively flat
ground and is not considered to be contributing sediment to the reservoir. A boat launch
near the dam has a small area of soil disturbance consisting of a compacted two-track dirt
path that leads to the reservoir. Most of the shoreline is well-vegetated and is not
contributing sediment into the reservoir. A dirt road is located on the west side of the
reservoir and has proper drainage structures and is maintained by the county. It does not
appear that upland forested areas are contributing to accelerated erosion or sedimentation
of the reservoir. A relatively new vault toilet has been installed near the dam along with a
vehicle turnout. The toilet is in good condition and does not appear to be leaking.

Researchers of the U. S. Geological Survey (Winter etal.1998) summarized ground water
and surface water processes affecting chemicals in lakes and wetlands and an excerpt
from their discussion that applies to nutrients is presented below.

“Lakes and wetlands also have distinctive biogeochemical characteristics with
respect to their interaction with ground water. The chemistry of ground water and
the direction and magnitude of exchange with surface water significantly affect
the input of dissolved chemicals to lakes and wetlands. In general, if lakes and
wetlands have little interaction with streams or with ground water, input of
dissolved chemicals is mostly from precipitation; therefore, the input of chemicals
is minimal. Lakes and wetlands that have a considerable amount of ground-water
inflow generally have large inputs of dissolved chemicals. In cases where the
input of dissolved nutrients such as phosphorus and nitrogen exceeds the output,
primary production by algae and wetland plants is large. When this large amount
of plant material dies, oxygen is used in the process of decomposition. In some
cases the loss of oxygen from lake water can be large enough to kill fish and other
aquatic organisms.

The magnitude of surface-water inflow and outflow also affects the retention of
nutrients in wetlands. If lakes or wetlands have no stream outflow, retention of
chemicals is high. The tendency to retain nutrients usually is less in wetlands that
are flushed substantially by throughflow of surface water. In general, as surface-
17
water inputs increase, wetlands vary from those that strongly retain nutrients to
those that both import and export large amounts of nutrients. Furthermore,
wetlands commonly have a significant role in altering the chemical form of
dissolved constituents. For example, wetlands that have throughflow of surface
water tend to retain the chemically oxidized forms and release the chemically
reduced forms of metals and nutrients.”

Most of the surface water flowing into the reservoir is from Timber Creek in which most
of the phosphorus is in the dissolved fraction. This indicates that ground water is the most
likely source of this inflow water. With very little evidence of man-made phosphorus
sources in Timber Creek, it is likely that the phosphorus entering the lake is mostly from
natural sources of ground water.

In the following discussion, Bronmark and Hansson (2005) describe dissolved oxygen
conditions in autumn and winter that are typical of shallow lakes.

“In autumn, the amount of solar energy reaching the lake is reduced and water
temperatures will decrease. Eventually, the lake water will overturn and
oxygenated water circulates down to the deeper strata (Fig. 2.5). At the formation
of an ice cover during winter, the exchange of oxygen with the atmosphere will be
blocked. If the ice is transparent, there will be a considerable production of
oxygen by photosynthesizing algae immediately under the ice, whereas in deeper
layers oxygen-consuming decomposition processes will dominate. The amount of
dissolved oxygen will thus decrease with increasing depth during the winter and
be particularly low close to the bottom (Fig. 2.5). If the ice is covered by a thick
layer of snow, photosynthesis and oxygen production will be almost completely
suppressed because of the lack of light. If this continues for a long period the
oxygen in the lake may be completely depleted, resulting in massive fish
mortality. This is called ‘winterkill’ and is especially common in shallow,
productive ponds and lakes where decomposition of large quantities of dead
organisms consumes a lot of oxygen.”

The changes in dissolved oxygen described above are different than the lake processes in
Manning Meadows reservoir. During the summer, the lake has temperature stratification
at about four meters and sometime between October and March, the water temperatures
become very cold throughout the profile. A rapid decrease in dissolved oxygen occurs
from the 7-meter depth to the bottom throughout the year. In March in the middle of the
ice-covered season, the lake has very low dissolved oxygen throughout the water profile.
This is likely caused by the decomposition of organic matter and the deep snow and ice
cover.

7.0 Source Assessment

This section identifies whether load reductions are necessary, and if so, what would be an
appropriate margin of safety for limits on sources of pollution while considering the
seasonal changes of the parameters of concern.
18

The results of the water quality data and land management activities in the watershed
indicate that natural processes are causing dissolved oxygen impairment in Manning
Meadows Reservoir. The primary sources of phosphorus loading into the Reservoir
include internal loading from bottom sediments and groundwater contributions to Timber
Creek.

As discussed in Section 6, dissolved oxygen impairment appears to be naturally occurring
and not caused by anthropogenic sources for Manning Meadows Reservoir within
the Fishlake National Forest. Since anthropogenic activities have not caused
the impairment, Manning Meadows Reservoir is recommended to be placed
in Category 4C of the State of Utah’s 303d List as not impaired by a pollutant.

8.0 Best Management Practices

Although Manning Meadows Reservoir has been determined to not be impaired due to
anthropogenic causes several recommended projects are included to help guide land
management efforts to preserve and improve current water quality conditions

Recommended practices:
• On private land, consolidate routes in the watershed draining into Manning Creek
and tributaries in order to reduce the numerous trails and routes caused by trucks
and ATVs some of which cross Manning Creek and the southern tributary of
Manning Creek. Avoid wet areas and avoid crossing Manning Creek or use small
bridges to cross. Move cattle frequently to keep livestock from congregating and
creating denuded areas in the uplands and springs.
• On National Forest lands, maintain the fence that keeps livestock out of the
wetland area of Manning Creek just above the reservoir. Designate areas where
dispersed camping should occur and control soil erosion from these areas. Limit
vehicle access to the reservoir to one boat launch and create proper drainage for
this route to control erosion and sediment movement. Where soil erosion appears
to be causing sediment to enter the reservoir, use best management practices to
control erosion such as planting seed and mulching bare soil areas, and placing
barriers such as branches, rocks, and in unwanted user created paths.

The Forest Service would be responsible for implementing work on National Forest lands
but when implementation would occur would depend upon available funding and Forest
Service priorities.

Other means of addressing the dissolved oxygen deficit is described below but is not
recommended for this reservoir. Several approaches for increasing dissolved oxygen in
lakes are described in Baker et al. (1993). Low levels of dissolved oxygen can occur in
natural and culturally-altered lake conditions primarily in the hypolimnion during long
periods of ice or snow and in dense macrophyte beds at night or following long periods of
cloud cover. Approaches to alleviating low dissolved oxygen problems include
19
decreasing the quantity of organic matter decomposing in the lake, increasing
photosynthesis, destratifying the lake, and directly aerating the lake.

Several techniques can been used to increase dissolved oxygen and each has their
limitations. Pump and baffle systems, consisting of water pumped on shore through a set
of baffles, are effective at increasing dissolved oxygen but freeze-up during the winter
can cause ice buildup that may in turn cause the baffles to be ineffective or become top
heavy and fall over. The system must be checked daily to ensure proper operation.
Artificial circulation eliminates thermal stratification and produces lake-wide mixing.
The technique is best used in lakes that are not nutrient limited because nutrient
concentrations are often higher in the hypolimnion and mixing can stimulate increased
algae growth. In addition, artificial circulation is not a viable option for coldwater fish
species that use the hypolimnion as a thermal refuge during summer. Hypolimnetic
aerators may be used to increase dissolved oxygen in the hypolimnion without disturbing
thermal stratification. However, hypolimnetic aerators require a large hypolimnion to
work properly and are generally ineffective in shallow lakes or ponds. Direct oxygen
injection into the hypolimnion has been effective at raising dissolved oxygen levels.
Snowplowing that removes at least 30 percent of the snow is effective in preventing
winterkill in shallow lakes with abundant rooted macrophytes. It has been noted that
even thin layers of snow can greatly decrease light penetration which decreases primary
productivity and can lead to dissolved oxygen depletion. An important option for lakes
with dissolved oxygen problems is to mange the fisheries for species that tolerate
relatively low levels of dissolved oxygen or that do not inhabit areas of the lake that
experience oxygen depletion such as the hypolimnion (Baker et al.).

In the late 1970s through the early 1990s, the Wasatch-Cache National Forest installed
mechanical circulation devices, bottled oxygen and air diffusers on several lakes to try to
break down the summer thermal stratification and to decrease the amount of time that the
lower lake depths are devoid of dissolved oxygen, or to directly oxygenate the lake water.
Aerators powered by solar panels were installed on Marsh Lake; barrel-type wind
aerators were installed on Sargent Lake, an unnamed lake east of Stateline Reservoir,
Graham Reservoir, and Teapot Lake; bottled oxygen was hauled into a couple small lakes
near Stateline Reservoir and diffused into the lake; and in partnership with Phillips
Petroleum, air was diffused throughout Quarter Corner Lake using air hoses attached to
the compressor plant located at a nearby oil pad. At Quarter Corner Lake, a fishing pier
was installed in anticipation of a year-round fishery but oxygen was still limited in the
lake. The Utah Division of Wildlife Resources still stocks trout in the lake for a put-and-
take fishery.

Oxygen monitoring in the lakes showed mixed results. The ability of the wind powered
circulators to bring about a complete mixing of the lakes that otherwise would be
thermally stratified has not been realized on these lakes. The effect on Sargent Lake and
Teapot Lake is that circulation had little effect on the oxygen/temperature profile yet had
a significant effect on the dissolved oxygen during the summer. However, Teapot Lake
has never been able to overwinter fish. Marsh Lake had a significant change in the
summer temperature profile but little change in the dissolved oxygen profile. The winter
20
dissolved oxygen in Marsh Lake increased after the first year but is most likely the result
of the breaching of the irrigation dam at the same time that the circulators were running
and the aquatic vegetation in the lake decreased by about one-half. These efforts were
abandoned in the early 1990s because of the very difficult environmental conditions for
operation and maintenance, the marginal results of the efforts, and the high costs to the
low benefits that were realized from the projects.

REFERENCES

Baker, J.P., H. Olem, C.S. Creager, M.D. Marcus, and B.R. Parkhurst. 1993. Fish and
Fisheries Management in Lakes and Reservoirs. EPA 841-R-93-002. Terrene Institute
and U.S. Environmental Protection Agency, Washington, D.C.

Bronmark, Christer and Lars-Anders Hansson. 2005. The Biology of Lakes and Ponds.
Oxford University Press.

Judd, H.J. 1997. Utah’s Lakes and Reservoirs, An Inventory and Classification of Utah’s
Priority Lake and Reservoirs. Utah Department of Environmental Quality, Division of
Water Quality.

Kent State. 2005. Internet site http://dipin.kent.edu.tsi.htm, The Great North American
Secchi Dip-In. excerpted and modified from Carlson, R.E. and J. Simpson. 1996. A
Coordinators Guide to Volunteer Lake Monitoring Methods. North American Lake
Management Society. 96 pp.

Olem, H. and G. Flock, eds. 1990. Lake and Reservoir Restoration Guidance Manual, 2nd
edition. EPA -440/4-90-006. Prep. by N. Am. Lake Manage. Soc. for U.S. Environ. Prot.
Agency, Washington DC.

Stokes, William Lee. 1986. Geology of Utah. Utah Museum of Natural History,
University of Utah and Utah Geological and Mineral Survey, Department of Natural
Resources. Salt Lake City ,Utah.

Utah, State of. 2005. Standards of Quality for the Waters of the State. R317-2, Utah
Administrative Code. Utah Department of Environmental Quality, Division of Water
Quality, Revised December 1, 2005.

Utah, State of. 2006. Utah’s 2004 303(d) List of Impaired Waters. Utah Department of
Environmental Quality, Division of Water Quality.

Utah, State of. 2007. Draft Water Quality Assessment Guidance. Utah Department of
Environmental Quality, Division of Water Quality, August 31, 2007.

21
Winter, Thomas C., Judson W. Harvey, O. Lehn Franke, and William M. Alley. 1998.
Ground Water and Surface Water A Single Resource. U.S. Geological Survey Circular
1139.