HomeMy WebLinkAboutCity Council Packet 04-04-2000 SpecialAgenda
City of Plymouth
Special Joint City Council and
Environmental Quality Committee Meeting
Tuesday, April 4, 2000
7:00 p.m.
City Council Chambers
1. Call to Order.
2. Receive presentation on Medicine Lake Watershed and Lake Management Plan
3. Adjourn
Agenda Number:
CITY OF PLYMOUTH
CITY COUNCIL AGENDA REPORT
DATE: March 30, 2000 for the City Council Meeting of April 4, 2000
TO: Dwight D. Johnson, City Manager
FROM: Ronald S. Quanbeck, Assistant City Engineer
SUBJECT: MEDICINE LAKE WATERSHED AND LAKE MANAGEMENT PLAN
BASSETT CREEK WATER MANAGEMENT COMMISSION
ACTION REQUESTED: No action is requested at this time.
BACKGROUND: The Bassett Creek Water Management Commission (BCWMC) is a joint powers
organization composed of the cities of Plymouth, Medicine Lake, Golden Valley, New Hope, Crystal,
Robbinsdale, Minnetonka, St. Louis Park, and Minneapolis. Over 50% of Plymouth is within this
watershed management organization (WMO). I am currently the City of Plymouth representative on the
BCWMC.
BCWMC has completed a water quality investigation of Medicine Lake and developed a final draft
report of a Medicine Lake Watershed and Lake Management Plan. The purpose of the April 4, 2000
meeting is to present the results of this study to the City Council, Environmental Quality Commission
EQC) and public and gather feedback regarding the results. The attached letter which includes the
report's Executive Summary was sent to Plymouth residents with property abutting Medicine Lake,
Association of Medicine Lake Area Citizens (AMLAC), City of Medicine Lake, BCWMC
Commissioners and individuals who have previously indicated to the Engineering Division interest in
receiving notice of this meeting.
Also attached is Table 8 from the report which provides costs and phosphorus removal effectiveness for
each of the structural improvements considered. The recommended improvements are listed as Option
Number 24 which is actually a combination of nine options. The City's 2000 Capital Improvement
Program includes funding in 2002 for a project to improve the water quality of Medicine Lake. The
project is intended to implement at least portions of this report.
RECOMMENDATIONS AND CONCLUSIONS: We recommend the Council and EQC receive the
information presented in the report and public comments for future consideration.
Ronald S. Quanbeck, P.E.
Assistant City Engineer
attachment: Letter
Table 8
N:\pw\Engineering\GENERAL\MEMOS\RON\Med Lk meeting.doc
CITY C
March 24, 2000 PLYMOUTH+
SUBJECT: MEDICINE LAKE WATERSHED AND LAKE MANAGEMENT PLAN
Dear Property Owner:
You are invited to attend a presentation at the Plymouth City Hall, 3400 Plymouth
Boulevard on Tuesday, April 4th at 7:00 p.m. on the recently completed Medicine Lake
Watershed and Lake Management Plan. This plan has been prepared for the Bassett Creek
Water Management Commission. The Plymouth City Council along with the City's
Environmental Quality Committee has scheduled this meeting and is inviting lake area
residents and other interested citizens to the meeting.
This lake management plan is the last plan to be completed by the Bassett Creek Water
Management Commission on the fifteen major water bodies within the area that drains to
Bassett Creek. Now that the Commission has completed all of the studies they are
preparing a water quality capital improvement program and will be setting priorities.
The City of Plymouth has scheduled improvements to improve water quality on Medicine
Lake for 2002. This meeting will be one of the first City meetings to gather information
prior to establishing priorities and the programs which will be undertaken.
Hopefully, your schedule will allow you to attend this meeting in order that you can
become more informed on lake improvement projects. For your information, I am
enclosing a copy of the executive summary from the report which will be presented at the
meeting.
Sincerely,
4
Fred G. Moore, P.E.
Director of Public Works
enclosure
N:\pw\Engineering\GENERAL\LTRS\FRED\2000\PropOwners_LakeMgmtPlan.d-
PLYMOUTH A Beautiful Pface To Live
3400 PLYMOUTH BOULEVARD • PLYMOUTH, MINNESOTA 55447-1482 • TELEPHONE (612) 509-5000
www.d.plymouth.mn.us
Final Draft Report
Medicine Lake
Watershed and Lake Management Plan
Volume 1: Lake and Watershed Conditions, Water Quality Analysis
Improvement Options and Recommendations
Prepared For:
Bassett Creek Water Management Commission
Prepared By:
Barr Engineering Company
Minneapolis, Minnesota
March 2000
Executive Summary
The purpose of this Management Plan (Plan) is to establish priorities and provide guidelines for the
cities of Plymouth, Golden Valley, Medicine Lake, New Hope. Minnetonka and Medina; the Bassett
Creek Water Management Commission (Commission): and citizens for meeting water quality goals
set for Medicine Lake. These goals were recommended for water bodies within the Bassett Creek
Watershed in the Draft Water Quality Management Plan (Barr Engineering Company, 1993a).
Medicine Lake, the second largest lake in Hennepin County, is considered the most important
recreational water body in the City of Plymouth. The lake has multiple public accesses, and is
intensively used during both summer and winter months. Fishing, boating, swimming, water-skiing
and aesthetic viewing are some of the major recreational uses made of the lake. In addition,
Hennepin Parks' French Regional Park and the City of Plymouth's East and West Medicine Lake
Parks, and East Medicine Lake Regional Trail are all located along the lakeshore. The Metropolitan
Council considers Medicine Lake a "Top Priority Lake" because of its multiple recreational uses and
public access. The Association of Medicine Lake Area Citizens (AMLAC) also values lake water
quality and has been involved in monitoring the health of Medicine Lake.
Medicine Lake has typically fallen below the Commission's water quality goals. Trend analyses of
historical water quality data for Medicine Lake indicate that while brief periods of poor water quality
occur annually during late -summer, its overall condition has remained steady. This steady level of
lake water quality, despite ongoing watershed development, is most likely due to the implementation
of watershed BMPs since 1993. Medicine Lake will continue to be affected by the problems that
occur when a lake's watershed has become urbanized. The increased volume and pollutant levels of
storm water runoff from the watershed result in a deterioration of lake water quality. This Plan
concentrates on the total phosphorus loading to the lake because phosphorus is the nutrient that
activates algal growth. A reduction in the phosphorus concentration in a lake is necessary to improve
or maintain water transparency.
The Medicine Lake watershed was divided into five drainage districts. Each drainage district was
evaluated for nutrient removal efficiency under existing conditions which was determined to be the
same as the proposed full -development land use conditions.
OOMA\PCOOCS\OOCS\2 t 0565\ t ES- I
n lake improvement options and site-specific structural BMPs for each drainage district were
evaluated. General B vlPs to be implemented throughout the watershed were identified.
Recommendations are discussed below:
In -Lake Improvement Recommendations
Medicine Lake receives more than 40 percent of its annual phosphorus load due to release from its
bottom sediments. Areal application of aluminum sulfate (alum) to the lake water can be used as a
long-term control of phosphorus release from the lake sediments. This in -lake treatment technique
will likely be effective for approximately 10 years, depending upon how well watershed nutrient
sources have been reduced.
Macrophyte management recommendations are presented to: (1) remove vegetation from beach areas
to ensure safe swimming conditions; (2) remove vegetation from public boat landings to insure
public access to the lake; (3) improve navigation within the lake through areas containing dense plant
beds; (4) improve recreational attributes of the lake; and (5) and reduce current Eurasian
watermilfoil, curlyleaf pondweed, and purple loosestrife growth to the greatest extent possible.
It is further recommended that boat landings, beach areas, and navigation channels throughout the
littoral region be treated with the herbicide Reward during mid-May, late June, and late July.
Treatment areas for swimming beaches and boat landings should be based upon the areas in need of
treatment to support the intended recreational use of these areas. Repeated treatment is expected to
support the intended beneficial uses of the lake and reduce the density of curlyleaf pondweed and
Eurasian watermilfoil in the lake.
Introduction of a natural predator to help control the purple loosestrife growth along the shore of
Medicine Lake is recommended. Two beetle species effectively prey upon purple loosestrife. They
include Galerucella pusilla and Galerucella calmariensis. It is recommended that the Commission
work with the Minnesota Department of Natural Resources (MDNR) to introduce the beetles in
purple loosestrife infested areas of Medicine Lake.
Site -Specific Structural BMP Recommendations
Specific recommendations for structural BMPs are provided for each of the drainage districts
discussed in the report. These recommendations include:
OOMA\PCOOCS\OOCS\210565\1 ES -2
I. Plymouth Creek Drainage District
Medicine Lake receives approximately more than 30 percent of its annual phosphorus load from
Plymouth Creek. Plymouth Creek represents more than 60 percent of the total phosphorus load from
the Medicine Lake watershed. One BMP option was identified to significantly reduce the amount of
phosphorus that enters the lake. This option involves constructing an alum treatment plant within the
Medicine Lake Park area, west of the Medicine Lake west bay, to provide additional treatment of the
higher soluble phosphorus concentrations in the storm water runoff from the Plymouth Creek
Drainage District. Implementation of this BMP, along with the other recommended BMPs, would
improve Medicine Lake water quality and ensure that the water quality goals will be met. This BMP
is the only watershed BMP, or combination of BMPs, proposed as part of this study that will
significantly improve lake water quality.
2. Ridgedale Creek Drainage District
Medicine Lake receives approximately 6 percent of its annual phosphorus load from Ridgedale
Creek. The Ridgedale Creek Drainage District represents approximately 12 percent of the total
phosphorus load from the Medicine Lake watershed. In addition, Ridgedale Creek represents nearly
70 percent of the total phosphorus load to the eastern half of the Medicine Lake west bay. One BMP
option was identified to significantly reduce the amount of phosphorus that enters the lake. This
option involves constructing an alum treatment plant adjacent to the wetland on the south side of the
Medicine Lake west bay to provide additional treatment of the higher soluble phosphorus
concentrations in the stormwater runoff from the Ridgedale Creek Drainage District. Implementation
of this BMP, along with the other recommended BMPs, would improve Medicine Lake water quality,
especially within the west bay, and ensure that the water quality goals will be met on a more
consistent basis.
3. Medicine Lake North Drainage District
Medicine Lake receives more than 2 percent of its annual phosphorus load from this drainage district,
which represents approximately 5 percent of the total phosphorus load from the Medicine Lake
watershed. The existing wet detention ponds in this drainage district provide satisfactory treatment
for its watershed. Implementation of additional structural BMPs is not recommended.
00MA\Pc00cs\00CS\210565\1 ES -3
4. Boat Landing Drainage District
Medicine Lake receives less than 2 percent of its annual phosphorus load from this drainage district.
which represents approximately 3 percent of the total phosphorus load from the Medicine Lake
watershed. The existing wet detention ponds in this drainage district provide adequate treatment for
its watershed. Implementation of additional structural BMPs is not recommended.
5. Medicine Lake Direct Drainage District
Medicine Lake receives approximately 8 percent of its annual phosphorus load from this drainage
district, which represents approximately 16 percent of the total phosphorus load from the Medicine
Lake watershed. This drainage district receives a relatively small amount of storm water treatment
and drains directly to Medicine Lake, either through overland flow or from smaller residential and
larger highway storm sewer systems. However, some opportunity for treatment of runoff is currently
available. Implementation of additional structural BMPs is recommended, wherever feasible, to
control the sediment and phosphorus inputs to the lake. These inputs have created sediment deltas
that have accumulated at various points along the lakeshore due to streambank erosion and untreated
highway and residential storm water runoff.
Geese and other waterfowl within this drainage district also represent a source of phosphorus to
Medicine Lake that should be minimized to the maximum practicable extent. The City of Plymouth
has been working with the MDNR and a specialist at the University of Minnesota to remove a portion
of the goose population from some lakeshore areas each year. This program should gradually
diminish the number of geese within the direct watershed over time. However, additional controls,
such as city-wide "no feeding" ordinances, habitat modifications, goose barriers, repellents and the
use of trained dogs should be considered to keep the goose population in check.
General BMP Recommendations
Require wet detention for all new or redeveloped properties, where applicable.
2. Adopt and enforce a watershed -wide (or City-wide) ban on the use of phosphorus fertilizers.
Continue to educate watershed residents about soil testing and the importance of using
phosphorus -free fertilizers.
3. Implement a program to educate watershed residents and lake users on other practices that
would reduce pollutants entering the lake.
OOMA\PCOOCS\OOCS\210565\1 ES -4
4. Enforce existing ordinances regarding litter and animal waste.
5. Implement street sweeping program that gives priority to the watershed areas within the
Medicine Lake Direct Drainage District.
6. Require/encourage vegetated buffer strips between maintained lawns and the lake or
detention ponds/wetlands.
Providing stormwater alum treatment for both the Plymouth Creek and Ridgedale Creek Drainage
Districts, additional wet detention treatment within the Medicine Lake Direct Drainage District, and
applying an alum treatment to the lake would help ensure that the Commission's Level I goals are
met on a more frequent basis during varying climatic conditions. In addition, the long-term
effectiveness of alum treatment depends, largely, upon the extent of watershed BMP implementation
to reduce outside nutrient sources.
ooMA\PCOOCS\oocs\210565\1 ES -5
Go
0
R
u
Ca -
ca X 0 0 0 0 0 0 0 0 0 0 0 0 0
d a d cn Lo LO ui U'i Ln LO Ln LO cn cn cn U')
E c `
to
A
CL
mi
O cD cD cD to co cD D O cD cD cD O c0
Y
L
U
U_
d
c0
m
V a Ycc ea oe 0o 0o 0 oo eo oa 0
y 0 O V V V V V V V V V
rna
r t at co n coto N om om tom mn com mCD vn oO rnco
O o. W Y N NN N N N N N N N N N
F- 0 O JJ
O D) CA O O O O C11 O CA O O
tCL 0
0 0 0 0 0 0 o n O o 0 0
o o 0 0 o rn IT v o n o
OD o m n v v n co co n v rn m
m 7 CA O
44%
C7 D) cD O CA
W MO0
Cl)
v NK V! N40 coH 69 CA cH m03, f!)
cU
C
Q
O O O O O m m n O N O O
H N V,
N C7O mn mKiOto7c7NnCoOm
ttv 69 fl
69 69
vN
603,
0U
c 2 A
Q0
0 0 0 0 0 0 0 0 0 0 0 0
O
C O_ C7 m N N_ N 01 U7
a3 N O m N O n O cD CV
O Co In n nU) to Of Ln n
0.0
U U
m cr)
M
m
A
fA f9 49 N CVj
df
c m
oa
a E N cv m co n m cb rn o R0
OZ
m c
0
c o a o o co
j C
C O O C 3 C m C C L C C
Cfl —O
C mU
to 0.
m 'NCQf CQ
C CO
OUa
CO
aaEL oa a) Oa y oQan 0a 0ma 0a 0 om c
a O mU
om
a-
a r- toa. o
6 E cmo. cVc
o m oN
C
a o co
cmma
o L c ammcm
oma 0 oaorn
r
2
0 mm -m 7 "'U m N_O D m mU203
N mY OL my X m a amto D mO mO D C CQ 9 E3 `' mU D
mC m °-m
m Cl) mm
m
c
m o
O
mL
m mUmm E mUomm mUmm m cc mp
m p mm
a mmm
m m
m
a L
o
m
m.0 mp mo m a mm=>>mm mm mcc(n-m 3: cc
o
m
2 3 LL in mmN mrna E 3 H C> N N c E H O.J N to m
p U O m C U m 7 ()
CO
U m U 7 U `ra 7 `mQ U `m U 'J O w c0
U7 U 3 pmj
C`
ca
Q d M
p m 7 Q 7 (n 7 c0 C
3
OQ . cm mm
a 3
O m 7 U
N,0
x O "' C
a
O 7
6 =
t0 -0 O O p U
c=
O
c a
O 7
m
O U 7
c a
0 7
c cD m
0 0 O J 7
Qf
m U O
QOi
O 7 U
c
O Cow0 ; ca U 0 cn Cr Q CL U 7 m U 3:,U n CL m cn U cn U m w m cn cc m n. U o 9 U 0
N '
U
L CLD
Q) UQ) -
L
3 >
C)
o_
E a)
7 `-
O o
O
Q)
y
3
o
Y cC
co
co E
C
O y
a) ca
O cC
E >0
CD E
UC
co Lo
ca 'a _
N O co
N O^cn UNOpd
Ern m?^
ccoac`c
rya
CDO
O
co
3R mc
m o c
7 y (O X ft{ E co poccm
EH= a) d0
N
c'ts CC
E Em tndo
m E NC u7
CD
Ccc a)m>._ E
C>> E v d E O m c0cD—E cE Eto
JR'n a m m
c -
fcY
E\c m ro N)c)o
tcma)EctDmorn
L E Cy E - CT
E o N c¢ c c
O U O d7rn .2 u) n UaaE c
m a) _J col O
a) a)
T T y O 11
N
O O d t0 d
C7 O d O 7 '73O - m v) II O v o 9 a)
7 7, n
T
p d O O Ln 7 O O O O O a) O
CL m n Ln Ln u-) n In In un to co In n n
m
E Nc y
m
CL
m
mi
T.
QC1 ID to m to N cD to cD cD O cD O O
Y O CTI CD m
J
m
U
O
L
U
m
d n. V V 0) O c7 to v V v V O v Cn cm
c7 c v C? T v v t C7 N N
c0
d
o
c7 V N 0to co
t0
C7
LO
O O V V N
0
N
N0.0
O C- er N CD c'7 7 O n v m N C))
L '- mCLmy toN mN Oc! c0 Cn nN ON CON 0 r- Oc0 c0 c0C'') coCl)
H 0 O JJ
C)) O n r` co D O O CA a)v 0) v
L
CL 0
O O O O OO O O O O O O O O
co N CA m O O 0 0 0 0 0 O O
m v C Cli v n ou) 000Oo C 0
N ' N cm N c0 r` r` C7 v cD M r`
N N CA m cn M 49 c9 NN co
M U A f9 to 69 40 49 v61 69 V!
c
a
o 0 0 o O0 00000 0 0
m n 0 O LO ffl 0 O 0 N O O CO N
r. cl) rn to v o o co v o Cn 0
U N 49 m r, m N m r- rn ch triO
c 2 r 409
44.
9699N
v C
Q0
V9 Vf
O O O O O 00 0 0 0 0 O O
u') N O O O 00 ff) O O O o O O
O) Cl to to Lc CA cn r, n v O CJ) v
t0 n 0 cD N CU u) N N co co CA n N
N v v N O O m co m IT
0.0 c7 69 N aD C)) O M m; c0 CO
m U V9. 0 fH fA n N N v Cl)
U K H u9 4H Vi M H 49
c 0.0
N Cl)v N ch v
a N N N N
O Z
o EN stn 0) m n
tr00u0uQnm
0 Q O Q O 0
10
v
C p p m
00
c u) a
O d C LL LL i0LL J m U 7
CL a_ o rn 30) E.21 c N ci
zc
N
N m O m w
om
cA t0 0 p
O
ln C m O
O m O o ym ym m e F m N 0 c L m
C A m C O U Q) CA
G U U d U a U CL 7 tV m CD m
O v L
In79777mj9EvyN
0 N N
m i m es cd E m Q) tC M 7 `nn J- O m . 9a 2 CmOcuO7OUT• N T m N y
NJ-
MDma) mar r-=cLa=G05rnJ0 a0
N '
U
L CLD
Q) UQ) -
L
3 >
C)
o_
E a)
7 `-
O o
O
Q)
y
3
o
Y cC
co
co E
C
O y
a) ca
O cC
E >0
CD E
UC
co Lo
ca 'a _
N O co
N O^cn UNOpd
Ern m?^
ccoac`c
rya
CDO
O
co
3R mc
m o c
7 y (O X ft{ E co poccm
EH= a) d0
N
c'ts CC
E Em tndo
m E NC u7
CD
Ccc a)m>._ E
C>> E v d E O m c0cD—E cE Eto
JR'n a m m
c -
fcY
E\c m ro N)c)o
tcma)EctDmorn
L E Cy E - CT
E o N c¢ c c
O U O d7rn .2 u) n UaaE c
m a) _J col O
a) a)
T T y O 11
N
O O d t0 d
C7 O d O 7 '73O - m v) II O v o 9 a)
7 7, n