United States
Environmental Protection
Agency
Environmental Research
Laboratory
Corvallis OR 97333
Research and Development
EPA-600/S3-82-005 Dec. 1982
Project Summary
Preliminary Assessment of
Multiphase Restoration
Efforts at Liberty Lake,
Washington
William H. Funk, Harry L Gibbons, and Gary C. Bailey
This document describes an investi-
gation with four main objectives: (1)
to establish background water quality
conditions immediately before and
after the application of major lake
restoration measures; (2) to determine
the effect of restoration measures
upon primary and secondary food
chain organisms within the lake and to
quantify changes in production; (3) to
demonstrate the feasibility of restor-
ing a relatively large and fragile soft-
water lake; and (4) to provide a
scientific body of information as to
which restoration methods may be
more effective in other lakes under
similar conditions.
This Project Summary was devel-
oped by EPA's Environmental
Research Laboratory, Corvallis, OR ,
to announce key findings of the
research project that is fully
documented in a separate report of the
same title (see Project Report ordering
information at back).
Introduction
In order to decelerate, reverse or
stabilize water quality deterioration
through overenrichment in a lake, the
sources of the nutrients must be
defined. In addition, the contribution of
each source must be determined as
accurately as possible and a mechanism
set in place to divert, reduce, or mitigate
that source of nutrient inflow. Further-
more, unless a concomitant education
program is established, the mitigating
efforts may come to naught because a
social, economic or political decision
may countermand restorative efforts.
Such an action may result in the
introduction of a new nutrient source or
the overloading of a formerly insignifi-
cant one.
Finally, there is a need for evaluation
of restorative efforts in order to predict
the future of the lake in question and
add to the scientific knowledge of lakes
of similar background. This report deals
with assessment of multiphase
restorative efforts at Liberty Lake,
Washington.
Study Area
Liberty Lake (Figure 1) is a softwater
lake (288 ha) of glacial origin located
25 km directly east of Spokane,
Washington. It is enclosed on three
sides by a small mountain range 300 to
900 m above the lake surface. Most of
the watershed (3,445 ha) lies in this
horseshoe-shaped basin, forested with
Ponderosa pine, grand fir, Douglas fir,
larch, white pine and aspen. The major
tributary. Liberty Creek, originates in
the higher southeastern slopes and
passes through a soil series of Moscow
and Springdale types before reaching
the Spokane and Semihoo muck series
in and adjacent to a marsh. The stream
-------
Spokane River
Drainage basin
Outline
4952
4956
Cable Park
Scale 1:62.500
Figure 1. Liberty Lake and water shed.
flows along the eastern margin of the
marsh (and until recently, overflowed
into it) before entering the lake. Most of
the tributary area is underlain by quartz-
feldspar-biotite paragneiss. Residential
areas occupy 87% of the shoreline and
overlie relatively shallow soils of the
Spokane series. Gneiss (west side and
north shore) and Columbia River basalt
(west shore) form the bedrock. A small
unnamed creek enters the lake from the
northwest. Until fall, 1979, waste
disposal had been by septic tank and
sewer system built in 1910, which
served approximately 40% of the
residents. In late 1978 and 1979, M.
2683
Round Mtn.
Kennedy Engineers completed a
collection system which now serves
about 2,000 permanent residents. The
system diverted 95% of the domestic
sewage from the lake basin.
The mean residence time of lake
waters is three years. Approximately
2.76 x 106 rrr3-yr1 of water is lost by
means of seepage, presumably through
the bottom at the northern end of the
lake. The lake may become weakly
stratified for short periods during the
middle and late summer.
The lake is heavily utilized. Eighty to
100,000 visits occur per season when
the swim areas and beaches are not
plagued by massive blue-green algal
blooms of Gloeotrichia, Anabaena,
Aphanizomenon. A three-year respite
from algae nuisances was made
possible by an earlier alum treatment in
1974 (Funk era/. 1975,1979; Funk and
Gibbons, 1979).
Assessment Methods
Early estimates of stream inflow, lake
level, and outflow had been made from
Gurley current meters and staff gauges
in the lake. Precipitation was measured
using standard rain and snow collection
devices. Initial water balances were
developed for the lake. For this
investigation, Parshall flumes were
installed on the Liberty Creek main
stems. The flumes were equipped with
battery operated flow meters and
discrete samplers for continuous flow
measurement and water sample
collection. County parks personnel
were contracted as backup to read and
record gauges. They also read rain-
snow gauges and evaporation pans.
Ground water input was estimated by
circumscribing the lake with 17 nests of
piezometers. Fifteen seepage meters
were installed, but no usable data were
collected due to vandalism. Sediments
were initially taken by Ewing corer, later
by a modified hand driven corer.
Phosphorus, nitrogen and selected
metals were analyzed by methods
outlined by the Environmental
Protection Agency (EPA) and the
American Public Health Association
(APHA).
Phyto- and zooplankton were col-
lected by rapid pump method at 1.0 m
intervals. They were identified and
counted according to methods outlined
in Edmondson (1959) and Edmondson
and Winberg (1971). Volume determi-
nations of phytoplankton were made as
described by Vollenweider et al. (1974)
and zooplankton by Bottrell et al. (1976).
Chlorophyll a was determined by
methods in Vollenweider et al. (1974)
and APHA (1975).
Primary productivity measurements
by carbon-14 procedures were carried
out in situ during 10:00 and 14:00 hours
at 2.0 m intervals. Counting was done
by liquid scintillation.
Macrophytes were harvested by
Scuba procedures. Plant tissues were
digested by methods described by
Gerloff and Krombholz (1966).
Laboratory chemical analyses of
inflowing streams and lake samples
were carried out using Technicon
-------
Autoanalyzer (II) procedures. Various
phosphorus constituents measured
were total phosphorus (TP), soluble
reactive phosphorus (SRP), and total
soluble reactive phosphorus (TSP).
Nitrogen components were total
Kjeldahl (TKN), ammonia (NH3), nitrite
(NO2), and nitrate (NO3)._Conservative
nutrients such as silica, sodium,
potassium, calcium, magnesium, and
iron were analyzed on a monthly basis.
Metallic elements were determined by
atomic absorption procedures (AAS).
Background and post-treatment
aluminum values were also determined
by AAS. Total organic carbon (TOC) was
determined by the ampule method
(Oceanographic International). Sample
preservation and analyses followed
methods of APHA and EPA.
Results and Discussion
The first restoration measure taken at
Liberty Lake was the diversion of spring
flood waters around the marsh. Phos-
phorus inflow to the lake by Liberty Creek
was reduced from 148 kg P in 1977 to
59 kg P by 1980. Nitrogen inflow was
reduced by only 5 to 10% because of its
greater migration through soils. Figures
2 and 3 show Liberty Creek surface
inflow and nutrient loading.
Estimates of ground-water input
made just prior to the completion of the
sewer collection system indicated that
the immediate area (784 ha) around the
lake contributed between 6.3 x 105 m~3
and 9.8 x 105 m~3 of water per year
depending upon precipitation. This flow
carried 150 to 300 kg P and 1700 to
3000 kg N toward the lake. A large
portion of this input has now been
curtailed by the sewage collection
system. It has been estimated that only
about 25 kg P is now reaching this lake;
however, it will be several years before
the shallow soils in the immediate lake
area are leached of excess nutrients.
Table 1 summarizes range and mean
values of lake waters at the two lake
stations for the three-year study. Figure
4 shows lake sample stations.
Extensive lake sediment core samples
were taken to (1) assess the nutrient
content (N & P) of the sediments; (2)
compare lake wide sediment types and
construct a bottom sediments map to
aid in later removal of rich sediment by
dredging; and (3) assess potential of
nutrient release from sediment.
By conducting laboratory tests under
a variety of simulated water quality
conditions (elevated, reduced and
anoxic oxygen levels), it was determined
West Fork, Liberty Creek
150
120
90
60
30
25
20
to
I 15
I 10
_j—i i /1 V—i—1_
i* i^i
J FMAMJJASONDJFMAMJJASOND JFMAMJJASOND
-149
Nitrogen
JFMAMJJ_ASONDJFMAMJJASONDJFMAMJJASOND
4
Phosphorus
JFMAMJJASONDJFMAMJJASONDJFMAMJJASOND
1978 1979 1980
Figure 2. Stream flow and nutrient loading West Fork, Liberty Creek.
that two of the seven main types of
sediments [refractory organic silt (ROS)
and heavy organic muck (HOM)] could
contribute a major phosphorus loading
to the lake under anoxic conditions
(Tables 2, 3 and 4). This region (120 ha)
was scheduled for dredging to remove
the top 0.5 m layer where 70 to 90% of
the P was located.
Evaluation of macrophyte weight and
nutrient content began at ice off in
spring (March-April) and continued
until October, at which time 50% or
more plants senesced and deteriorated.
First estimates were made in Fall, 1974.
This study was initiated in 1978 and will
continue through 1982. Dredging
(Spring, 1981) removed 40% of the
more abundant beds. Mean ash free dry
weight of the macrophytes at maximum
standing crop for 1978, 1979, and 1980
was 36,982 kg, 101,190 kg, and 58,939
kg, respectively. The P content was
estimated to be in 1978 (103 kg), 1979
(207 kg), and 1980 (230 kg). Regrowth
will be assessed during 1981 -82. Figure
5 indicates distribution of aquatic
macrophytes. Tables 5, 6, and 7 show
biomass by contour depth.
To assess the effect of restoration
measures upon benthic organisms, ini-
tial sampling began in 1977 at 17
locations. During 1978, a modified
stratified random sampling system was
adopted which took into account the
major sediment substrate types delin-
eated by coring procedures. Figure 6
delineates the distribution of benthic
invertebrates. Sampling conducted
before and after the alum treatment
indicated no significant difference at the
95% level between the population
numbers of chironomids, oligochaetes
and total organisms in samples
obtained. Because of the extensive data
collected before treatment, this study is
-------
East Fork, Liberty Creek
150
120
S 90
*
^ 60
30
JFMAMJJASONDJFMAMJJASONDJFMAMJJASOND
5.33
Phosphorus
JFMAMJJASONDJFMAMJJASOND J FMAMJJASONO
1978 1979 1980
Figure 3. Stream flow and nutrient loading East Fork, Liberty Creek.
Table 1.
Summary of 1979-80 Selected Water Quality Conditions at Liberty Lake,
Washington ffjg/l Except Where Noted)
Southeast Station
Northwest Station
Parameter
Mean Min Max Mean Min
Max
TP
TSP
SRP
N-Ammonia
N-Nitrite-Nitrate
Alkalinity (mg/l) fas CaCOd
HC03
C03
CO2
D.O. (mg/l)
pH(-logl-H-)
Secchi Disc
-------
Bacteria declined rapidly from surface
waters, most likely after being attracted
to or immersed in the floe. Figure 8
shows both decreased bacterial
numbers and increased Secchi disc
visibility as the floe sank to the bottom.
Summary
Low buffering capacity, shallowness,
and relatively long detention time of
Liberty Lake waters has precluded a
large one-time restoration effort. In
addition, the high rate of use by
residents, park visitors, fishermen, and
water sports enthusiasts has made a
stepwise treatment the most judicious
route to follow. This procedure also
insures protection of those whose
livelihood depends upon seasonal use
of the lake.
The most distinctive asset in terms of
restoration protection has been the
undisturbed upper watershed of Liberty
Lake. Phosphorus and nitrogen content
of inflowing waters are low unless
overflow flushes additional nutrients
from the adjoining marsh.
A 15 to 20% reduction in phosphorus
input has been achieved by diverting
flood waters away from the marsh and
to the lake through repair of the West
Fork of Liberty Creek.
Sewering of 95% of the residential
area around the lake has diverted
another 150 to 300 kg of phosphorus
and 1700 to 3000 kg nitrogen from its
yearly movement to the lake. It is
estimated that septic tank drainage
beds will continue to leach for another
four to seven years depending upon the
hydraulic pressure placed on them.
The importance of reducing the
macrophyte beds and their rich
substrata cannot be overemphasized.
Mawson (1980) has shown that when
the sediments become anaerobic, a
potential 150 to 290 kg phosphorus can
be released. Based upon estimates of
phosphorus contained in algae, the
potential release of phosphorus from
macrophytes and sediments could
theoretically produce 77 to 100 metric
tons of algae in the water. After dieoff
and decay of macrophyte beds and
subsequent algal blooms in 1971 and
1973, we estimated approximately 70
metric tons of debris on the beaches
(Funkef al. 1975).
Suction dredging in the late winter
and spring of 1981 removed approximate-
ly 33% of the top sediment and about
40% of the heavier macrophyte growth
area. Another alum treatment of 10
mg-L"1 was completed after dredging to
\ Unnamed Outlet
Sandy
Beach
Alpine
Shores
Wicomico
Beach
0 450 900 1800 Ft
;00200 300 50° M
Scale
Depth in Meters
MacKenzie
Bay
Dreamwood Bay
\
East Inlet
Liberty Creek
Legend
Water Quality Sampling Stations
Sediment cores taken in 1974
Cores taken March 15, 1978
Cores taken August 30, 1978
Figure 4. Sample stations. Liberty Lake.
Table 2.
Average Dissolved Oxygen Concentration, Average pH and Standard
Deviations for HOM and ROS (Mawson 1980)
DO
(mg/l)
Standard
Deviation
Standard
Deviation
Anaerobic
Reduced 02
Aerobic
Anaerobic
Reduced O2
Aerobic
0.0
2.77
8.36
0.0
3.1
6.84
HOM*
0.41
0.95
ROS**
0.53
0.96
6.65
6.63
6.96
6.55
6.70
7.02
0.37
0.27
0.46
0.76
0.75
0.35
Heavy organic muck
Refractory organic silt
-------
Table 3. Summary of Number of Observations fnj. Slope of Concentration Over
Time (k). Correlation Coefficients (r). Release Rates (k*J, and Confidence
Levels for Average Observed Concentrations for ROS** Sediment
(Mawson 1980)
Confidence
n k(mg/l-day) r k*(ug/m /hr) Levels Analysis
Anaerobic
Reduced O2
Aerobic
Anaerobic
Reduced 02
Aerobic
Anaerobic
Reduced O2
Aerobic
28
30
16
34
26
17
34
26
17
0.007
0.001
0.000
0.001
0.000
0.000
0.001
0.000
5.283 x 10~*
0,909
0.330
0.092
0.772
0.455
0.319
0.807
0.277
0.000
12.7
1.22
0.186
7.10
1.40
0.3057
2.75
0.393
9.79x10's
99%
<99%
<95%
99%
95%
<95%
99%
<95%
<95%
T-P
T-P
T-P
TSP
TSP
TSP
SRP
SRP
SRP
**Refractory organic silt
Table 4.
Summary of Number of Observations (n). Slope of Concentration Over
Time (k). Correlation Coefficients (r). Release Rates (k*), and Confidence
Levels for Average Observed Concentrations for HOM** Sediment
fMawson 1980}
Confidence
n kfmg/l-day)
r k*(ug/m /hr) Levels Analysis
Anaerobic
Reduced O2
Aerobic
Anaerobic
Reduced O2
Aerobic
Anaerobic
Reduced O2
Aerobic
34
82
26
34
82
26
34
82
34
0.003
0.001
0.000
0.002
0.001
6.9 x 70-6
0.002
0.001
1.23 x 70-5
0.693
0.839
0.411
0.707
0.779
0.026
0.832
O.750
0.290
5.42
2.48
0.399
2.698
1.41
0.011
3.071
0.10
1.87 x W'a
99%
99%
95%
99%
99%
<95%
99%
99%
<95%
TP
TP
TP
TSP
TSP
TSP
SRP
SRP
SRP
*Heavy organic muck
Funk, W. H., et a/.. 1975. Determi-
nation, extent, and nature of nonpoint
source enrichment of Liberty Lake
and possible treatment. Washington
Water Research Center Report No.
23, Washington State University,
Pullman, WA.
Funk, W. H. and H. L. Gibbons. 1979.
Lake restoration by nutrient
inactivation. In.: Lake Restoration,
Proceedings of a National
Conference. EPA-440/5-79-001.
Funk, W. H., H. L. Gibbons and G. C.
Bailey. 1979. Effect of restoration
procedures upon Liberty Lake. First
status report. In: Limnology and
Socioeconomic Evaluation of Lake
Restoration Projects. EPA-600/3-79-
005.
Gerloff, G. C. and P. H. Krombholtz.
1966. Tissue analysis as a measure of
nutrient availability for the growth of
angiosperm aquatic plants. Limnol.
Oceanogr. 11(4):529-537.
LeCain, G. D. 1981. Groundwater flow
and phosphorus input to Liberty Lake,
Washington. M.S. Thesis, Washington
State University, Pullman, WA.
Mawson, S. 1980. The impact of the
sediments on the phosphorus loading
of Liberty Lake, Washington as a
result of diffusion. M.S.Thesis,
Washington State University,
Pullman, WA.
Vollenweider, R. A. 1974. A manual on
methods for measuring primary pro-
duction in aquatic environments. 2nd
ed. IBP Handbook No. 12, Blackwell,
London.
reduce phosphorus released by
suspended sediments. This later treat-
ment also helped seal freshly exposed
sediments and is expected to aid in
breaking the nutrient cycle without
major impact on the buffering capacity
of the lake.
The ultimate goal is to reduce
controllable nutrient input (especially
phosphorus) by at least 50% and to
assess the benefit or value of each
restoration measure put into practice.
Barring undesirable land use
practices beyond controlled areas and
massive influx of human populations,
we are optimistic about the future of
Liberty Lake.
References
Bottrell, H. H. et al. 1976. A review of
some problems in zooplankton
production studies. Norw. J. Zool.
24:419-456.
Edmondson, W. T. (ed.) 1959. Fresh-
water biology. 2nd ed. Wiley, New
York, N.Y.
Edmondson, W. T. and G. G. Winberg
(eds.) 1971. A manual on methods for
the assessment of secondary
productivity in freshwaters, IBP
Handbook No. 17, Blackwell, London.
-------
\ Unnamed Outlet
Sandy
Beach
Alpine
Shores
Wicomico
Beach
0 450 900 1800 Ft.
100 200 300 500 M
Scale
Depth in Meters
MacKenzie Bay
Dream wood Ba y
^•:'j ' J/// \
East Inlet
Liberty Creek
West Fork Inlet
Emergent nuphar sp. beds
Mostly Potamogeton amplifolius
Mostly Elodea canadensis (with nitella sp.)
Ceratophyllum demersum with nitella sp. and E. canadensis
Ceratophyllum dominance displaced by E. canadensis in 1978
This zone has Potamogeton panormitanus and P. pectinatus from May to
August.
Potamogeton panormitanus and P. pectinatus increases at greater depths.
I I Patchy distribution of Elodea canadensis and Potamogeton spp.
Figure 5. Aquatic macrophyte distribution.
-------
Table 5. Macrophyte Biomass and Phosphorus Content at Maximum Standing
Crop. August 2, 1978. Liberty Lake, Washington
Depth
(ml
Area
(m2)
X 103
Mean
AFDW*
(g/m2)
Mean
AFDW
(kg)
Location: Southern end and along east
0-1
1-2
2-3
3-4
4-5
5-6
34.37
26.41
27.82
65.24
140.68
259.97
32
126
171
64
46
21
1099.8
3327.7
4757.2
4175.4
6471.3
5459.4
Mean Dry
Weight
(g/m2)
Mean Dry
Weight
Contour
%P
Total P
Contour
(kg)
side of Lake including MacKenzie Bay.
47.2
185.1
257.7
188.9
81.9
31.7
1622.3
4888.5
7169.2
12323.8
11521.7
8241.0
0.19
0.22
0.16
0.11
0.16
0.17
3.1
10.8
11.5
13.6
18.4
14.0
Sub-total southern portion of Lake 71.4
Location: Remainder of Lake (eastern portion of Lake)
2-4 133.0 87.9 11692.0 169.0 22477.0 0.14 31.5
Total: 36982.80 102.9
*Ash free dry weight
Table 6. Macrophyte Biomass and Phosphorus Content at Maximum Standing
Crop. August 21, 1979, Liberty Lake. Washington
Depth Mean Mean Mean Dry Mean Dry Total P
Depth (m2) AFDW* AFDW Weight Weight Contour
(m) x 103 (g/m2) (kg) fff/m") Contour % P (kg)
Location: Southern end and along east side of Lake including MacKenzie Bay.
0-1
1-2
2-3
3-4
4-5
5-6
6-7
34.4
26.4
27.8
65.2
140.7
260.0
86.6
33
82
133
129
103
140
85
1134.2
2165.6
3700.0
8416.0
14490.0
36395.8
7361.0
38
101
164
161
127
171
103
13O6.O
2667.4
4562.5
10503.6
17866.3
44459.9
8919.8
0.19
0.22
0.16
0.11
0.16
0.17
0.22
2.5
5.9
7.3
11.6
28.6
75.6
19.6
Sub-total southern portion of Lake 151.0
Location: Remainder of Lake
27527.4 56.0
Total: 101190.0 207.10
*Ash free dry weight
-------
Table 7.
Depth
(m)
Macrophyte Biomass and Phosphorus Content at Maximum Standing
Crop, August 22, 1980. Liberty Lake. Washington
Area Mean Mean Mean Dry Mean Dry
(m*) AFDW* AFDW Weight Weight
x 703 (g/m2) (kg) (g/m2) Contour
Total P
Contour
% P (kg)
Location: Southern end and along east side of Lake including MacKenzie Bay.
0-1
1-2
2-3
3-4
4-5
5-6
34.4
26.4
27.8
68.2
140.7
260.0
0
71.6
143.2
93.0
1890.2
3981.0
6342.6
118.4 16658.9
70.3 18278.0
0
73.0
146.0
132.2
146.0
87.9
1927.2 0.25
4058.8 0.30
9016.0 0.29
20542.2 0.27
22854.0 0.30
Sub-total southern portion of Lake
Location: Remainder of Lake
11789.0
Total: 58939.70
4.9
12.2
26.1
55.5
68.6
167.3
62.7
230.0
*Ash free dry weight
-------
\ Unnamed Outlet
\
Sandy
Beach
Alpine
Shores
Wicomico
Beach
Dreamwood Bay
N
0 450 900 1800 Ft.
100 200 30° 50° M
Scale
Depth in Meters
MacKenzie Bay
\
East Inlet
Liberty Creek
West Fork
Inlet
Legend
I I Relatively low benthic insect numbers (< 1,000 organisms/M2)
j^V^d Moderate benthic insect numbers (1,000 to 2,000 organisms/M2)
|y%%%! Moderately high benthic insect numbers (2,000 to 4,000 organisms/M2)
^§^ High benthic insect numbers (4,000 to 6,000 organisms/M2)
Figure 6. Invertebrate distribution.
600
MAMJJASONDJFMAMJJASONDJFMAMJJASONO
1978 1979 1980
Figure 7. Phytoplankton production, (mg C fixed m~3-day~*J
10
-------
0-
Surface
Northwest Station
Alum Treatment
1.0
CO
g
.*•**
•5
u
"5
?
ct
!
Li
ii.-_. ik
^_
S
o
o
\
"5
"5 •
o
m
1
•2. "
50
40
30
20
10
0
9/17
Bottom 9/13 10/5 10/21 10/23 10/25 11/2
1980
Figure 8. Bacteria decrease and Secchi disc visibility increase after October 20
alum treatment.
William H. Funk. Harry L. Gibbons, and Gary C. Bailey are with Washington
State University, Puff man, WA 99164.
Spencer A. Peterson is the EPA Project Officer (see below).
The complete report, entitled "Preliminary Assessment of Multiphase Restora-
tion Efforts at Liberty Lake, Washington," (Order No. PB 82-188 251; Cost:
$9.00, subject to change/ will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Environmental Research Laboratory
U.S. Environmental Protection Agency
Corvallis, OR 97333
11
. S. GOVERNMENT PRINTING OFFICE: 1983/659-095/558
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