HomeMy WebLinkAboutCity Council Resolution 1990-194CITY OF PLYMOUTH
Pursuant to due call and notice thereof, a Regular --- meeting of the
City Council of the City of Plymouth, Minnesota, was held on the 51]L -day of
March , 192L_ The following members were present: Mayor Bergman•
e following members were absent: None
Councilmember Vasiliou introduced the following Resolution and
moved its adoption:
RESOLUTION 90-194
FINDING THE FINAL ENVIRONMENTAL IMPACT STATEMENT FOR THE BASS CREEK BUSINESS
PARK TO BE ADEQUATE (89061)
WHEREAS, Minnesota Environmental Quality Act provides for the preparation of
certain environmental documents proposed development projects that meet
criteria established by the rules of the Minnesota Environmental Quality
Board; and,
WHEREAS, the City of Plymouth has made cErtain findings of fact regarding the
proposed Bass Creek Business Park which appear in Appendix A to this
resolution; and,
WHEREAS, the City of Plymouth has reviewed the comments received regarding the
Final Environmental Impact Statement for the proposed project and has
responded to those comments as contained in Appendix B to this resolution;
NOW, THEREFORE, BE IT HEREBY RESOLVED BY THE CITY COUNCIL OF THE CITY OF
PLYMOUTH, MINNESOTA, that it should and hereby does find the Final
Environmental Impact Statement for the proposed Bass Creek Business Park to be
adequate, consistent with the rules of the Environmental Quality Board.
The motion for adoption of the foregoing Resolution was duly seconded
by Councilmember Ricker , and upon vote being taken thereon,
the following voted in favor thereof: Mayor Bergman. Councilmembers
The following voted against or abstained None
Whereupon the Resolution was declared duly passed and adopted.
APPENDIX A TO RESOLUTION 90 - 194
FINDINGS OF FACT
1. The Bass Creek Business Park falls within the
mandatory EAW categories of Minn. Rules, part 4410.4300,
subp. 14, items A(3) and B(3) (December 19, 1988) and within
the mandatory EIS categories of Minn. Rules, part 4410.4400,
subp. 11, items A(3) and B(3) (December 19, 1988), because the
Project involves construction of a new mixed office,
office/showroom, commercial, warehouse, and manufacturing
facility in excess of the threshold square footages specified
for a second class city.
2. The Responsible Governmental Unit ("RGU") is the local
governmental unit, the City of Plymouth ("City"). Minn. Rules,
parts 4410.4300, subp. 14, items A and B and 4410.4400,
subp. 11, items A and B (December 19, 1988).
3. The proposer of the Project is Opus Corporation.
4. The Scoping EAW and Draft Scoping Decision were
prepared by the City with assistance from the proposer, who
submitted completed data portions to the RGU for its
consideration and approval. Minn. Rules, part 4410.1400
(December 19, 1988).
r5. The Scoping EAW was prepared in a form approved by the
Minnesota Environmental Quality Hoard ("EQH"). Minn. Rules,
part 4410.1300 (December 19, 1988).
6. The Scoping EAW addressed th following major
categories:
a. Identification of the Project by project name,
project proposer, and project location;
b. Identification of the RGU, EAW contact person,
and instructions for interested persons to submit
comments;
C. Description of the Project, methods of
construction, quantification of physical
characteristics and impacts, project site description,
and land use and physical features of the surrounding
area;
d. Resource protection measures that have been
incorporated into the project design;
e. Major issues sections identifying potential
environmental impacts and issues that required further
investigation before the Project was commenced; and
f. Known governmental approvals and reviews
required, applied for, or anticipated, and the status
of any applications made, including permit conditions
that were ordered or being considered.
Minn. Rules, part 4410.1200 (December 19, 1988).
7. The City issued the Scoping EAW and Draft Scoping
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wDecision on August 25, 1989, and within five (5) days thereof
provided a copy of the Scoping EAW and Draft Scoping Decision
to the EQB staff.
8. On August 25, 1989, the City submitted one copy of the
Scoping EAW and Draft Scoping Decision to all agencies listed
on the official EQB Mailing List, including:
a. Each member of the EQB;
b. Opus Corporation;
C. The U.S. Corps of Engineers;
d. The U.S. Environmental ProtecLion Agency;
e. The U.S. Fish and Wildlife Service;
f. The State Historical Society;
g. The Environmental Conservation Library,
h. The Legislative Reference Library; and
i. The regional development commission (the
Metropolitan Council) and regional development library
(the Ridgedale-Hennepin Area Library).
Minn. Rules, part 4410.1500, item A (December 19, 1988).
9. On August 25, 1989, the City provided a press release,
which contained a notice of availability of the Scoping EAW and
Draft Scoping Decision for public review, to the EQB Media
Mailing List, the Wayzata Weekly News, the Plymouth Post -News,
and the Minneapolis Star Tribune. The press release also
included the name and location of the Project, a brief
description of the Project, the location at which copies of the
' Scoping EAW were available for review, the date the comment
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0 period expired, the procedures for commenting, and the time,
place and date of the public scoping meeting.
10. Notice of the availability of the Scoping EAW and
Draft Scoping Decision was published in the EQB Monitor on
September 4, 1989, with an accompanying notice of a public
scoping meeting to be held on September 25, 1989.
11. The thirty -day scoping period began on September 4,
1989 and ended on October 4, 1989. Minn. Rules,
part 4410.2100, subp. 3, item A (December 19, 1988).
12. The public scoping meeting was held at the Plymouth
City Center from 4:30 p.m. to 7:00 p.m. on September 25, 1989,
which date was not less than fifteen days after publication of
the notice of availability of the Scoping EAW. Minn. Rules,
part 4410.2100, subp. 3, item B (December 19, 1988).
13. During the thirty -day scoping period, the following
written comments were submitted:
a. Metropolitan Council letter, dated October 3,
1989; and
b. Minnesota Department of Natural Resources letter,
dated October 4, 1989.
In addition, the following written comment was submitted after
the close of the thirty -day scoping period:
a. Minnesota Historical Society letter, dated
October 10, 1989.
These written comments are reproduced in Appendix A of the
. Scoping Decision.
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i14. No oral comments were received at the public scoping
meeting on September 25, 1989.
15. The Plymouth City Council approved the Scoping
Decision on October 16, 1989. The Scoping Decision was
distributed on October 27, 1989 to all persons and
organizations on the EQB Mailing List and to all other persons
or organizations who commented on the Scoping Decision, which
date was within fifteen days after the thirty-day scoping
period ended at 4:30 p.m. on October 4, 1989. Minn. Rules,
part 4410.2100, subp. 3, item C (December 19, 1988).
16. The Scoping Decision contained the following:
a. The issues to be addressed in the EIS;
b. Identification of the permits for which
information was being gathered concurrently with EIS
preparation;
C. Identification of the permits for which a record
of decision would be required;
d. Identification of the alternatives that would be
addressed in the EIS;
e. Identification of potential impact areas
resulting from the Project itself and from relat• '
actions which would be addressed in the EIS; and
f. Identification of necessary studies requiring
compilation of existing information or the development
of new data that could be generated within a
reasonable period of time and at a reasonable cost.
Minn. Rules, part 4410.2100, subp. 6 (December 19, 1988).
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I
17. The City's response to the comments received during
and after the scoping period can be found in Section 7.0 (pages
10-12) of the S:oping Decision.
18. An EIS preparation notice was published in the EQB
Monitor on October 30, 1989. The notice contained a summary of
the Scoping Decision. Minn. Rules, part 4410.2100, subp. 9
(December 19, 1988).
19. The City distributed to the Plymouth Post -News, the
Wayzata Weekly News, and the Minneapolis Star Tribune a press
release announcing the Scoping Decision, giving notice of EIS
preparation. Minn. Rules, part 4410.2100, subp. 9
(December 19, 1988).
20. A Draft EIS was issued by the City on November 29,
1989.
21. Notice of Draft EIS availability was published in the
EQB Monitor on November 27, 1989.
22. The City supplied a press release to the Plymouth
Post -News, the Wayzata Weekly News, and the Minneapolis Star
Tribune on November 29, 1989. Minn. Rules, part 4410.2600,
subp. 6 (December 19, 1988).
23. Both the notice of availability in the EQB Monitor and
the press release contained notice of the date, time and place
of the Draft EIS informational meeting, notice of the location
of the copy of the Draft EIS available for public review, and
notice of the date cf termination of the comment period. Minn.
Rules, part 4410.2600, subp. 7 (December 19, 1988).
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! 24. The entire Draft EIS was distributed to all persons
and organizations who commented on the Scoping EAW, both before
and after the close of the comment period, Hennepin County, the
cities of Maple Grove, Brooklyn Park and New Hope, and also to
those persons and organizations on the EQB Mailing List,
including:
a. Those governmental units which have authority to
permit or approve the Project, to the extent kn,?wn;
b. Opus Corporation;
C. The EQB and EQB staff;
d. The Environmental Conservation Library;
e. The Legislative Reference Library; and
f. The regional development commission (the
' Metropolitan Council) and the regional development
library (the Ridgedale-Hennepin Area Library).
Minn. Rules, part 4410.2600, subp. 3 (December 19, 1988).
25. The Draft EIS informational meeting was held at the
Plymouth City Center from 4:30 p.m. to 7:00 p.m on December 21,
1989, which date was not less than fifteen days after
publication of the notice of availability in the EQB Monitor.
No oral testimony was received, and thus there is no transcript
of the meeting. Minn. Rules, part 4410.2600, subp. 8
(December 19, 1988).
26. The record remained open for public comment until
January 4, 1990, which date was not less than ten days after
the last date of the informational meeting. Minn. Rules, part
4410.2600, subp. 9 (December 19, 1988).
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11 27. During the Draft EIS public comment period, written
comments were received from the following persons and
organizations:
a. City of Maple Grove, James Deane, Mayor, letter
to Charles E. Dillerud dated December 22, 1989;
b. Metropolitan Council, Steve Keefe, Chair, letter
to Blair Tremere dated December 27, 1989, with two
attached reports dated December 18, 1989 and
December 21, 1989; and
C. Suburban Hennepin Regional Park District,
David K. Weaver, Director, letter to Blair Tremere
dated January 4, 1990.
In addition, written comments were received from the following
/ persons and organizations after the close of the Draft EIS
public comment period:
a. City of New Hope, Daniel J. Donahue, City
Manager, letter to Blair Tremere dated January 16,
1990 (facsimile received by Plymouth on January 16,
1990, and original by mail on January 17, 1990);
b. Minnesota Department of Natural Resources,
Thomas W. Balcom, Supervisor, letter to Blair Tremere
dated January 4, 1990 (postmarked January 9, 1990, and
received by Plymouth on January 10, 1990);
s• Minnesota Department of Transportation, Isaac
McCrary, Jr., Environmental Coordinator, letter to
Blair Tremere dated January 9, 1990 (received by
Plymouth on January 10, 1990); and
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d. Minnesota Pollution Control Agency,
Debra L. McGovern, Director, letter to Blair Tremere
dated January 8, 1990 (received by Plymouth on
January 9, 1990).
The above written comments are reproduced in Appendices C and D
of the Final EIS.
28. The City's responses to these comments can be found in
Sections 3.0, 4.0, and 9.0 of the Final EIS (pages 10-11,
12-15, and 20-42, respectively).
29. The Final EIS was issued by the City on February 5,
1990.
30. The notice of Final EIS availability was published in
the EQB Monitor on February 5, 1990.
r31. A press release containing notice of Final EIS
availability was issued to the Plymouth Post -News, the Wayzata
Weekly News, and the Minneapolis Star Tribune on February 5,
1990. Minn. Rules, part 4410.2700, subp. 5 (December 19, 1988)
32. Both the notice of Final EIS availability in the EQB
Monitor and the press release contained notice of the location
of the Final EIS available for public review and notice of the
opportunity for public comment on the adequacy of the Final
EIS. Minn. Rules, part 4410.2700, subp. 6 (December 19, 1988).
33. Copies of the Final EIS were mailed by the City to all
persons and organizations who have commented during the EIS
process, to Hennepin County, to the City of Brooklyn Park, and
to those on the EQB Mailing List.
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34. It has been at least ten days since the publication in
the EQB Monitor of the notice of availability of the Final
EIS. Minn. Rules, part 4410.2800, subp. 3 (December 19, 1988).
B. Addressing Issues Revised in Scopine.
35. The Scoping Decision delineated the following issues
to be addressed in the EIS:
a. The impact of the Project on local and regional
transportation systems providing access to the Project;
b. The impact of construction and Project -related
noise on receiver sites near the Project;
C. Control of fugitive dust generated by
construction activities;
d. The impacts on groundwater resulting from
temporary dewatering during certain construction
periods;
e. The amount of solid waste to be generated by the
Project and the capabilities of local and regional
waste disposal facilities;
f. Soil erosion control measures to be used during
Project construction;
g. A survey of the Project site for historical,
architectural, cultural, or archaeological sites;
h. The impacts of the Project on on-site protected
wetlands and shoreland zones;
i. The impacts of Project construction and
10 development on on-site and adjacent wildlife habitat
and vegetation;
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j. The impacts of increased surface and storm water
runoff generated by the Project;
k. Estimation of the amounts of sanitary sewage
which will be generated by the Project and the
capabilities of existing facilties to transport and
process these amounts;
1. Project utility needs;
M. The economic, employment, and sociological
impacts of the Project;
n. The impacts of the Project on on-site prime
farmlands; and
o. The impact of the Project on the adjacent Eagle
Lake Regional Park.
i36. The City included in the EIS all issues raised during
the scoping period for which information could be reasonably
obtained.
37. The Final EIS addresses and analyzes all of the
foregoing issues.
C. Responses to Comments.
38. Comments concerning the issues raised in the scoping
process were received during the Draft EIS review. The City's
responses to these comments are set forth on pages 10-15 and
20-92 of the Final EIS.
39. The following comment was received during the Final
EIS comment period:
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Ia. City of Maple Grove, Randall Graves, Community
Development Director, letter to Blair Tremere dated
February 20, 1990.
In addition, 'the following two comments were received after the
close of the Final EIS comment period:
a. Suburban Hennepin Regional Park District,
David K. Weaver, Director, letter to Blair Tremere
dated February 16, 1990 (received by Plymouth on
February 21, 1990); and
b. Preliminary Metropolitan Council report dated
February 15, 1990, prepared by Richard E. Thompson
(facsimile received by Plymouth un February 21, 1990),
as amended by the Metropolitan and Community
Development Committee and adopted by the Metropolitan
Council on February 22, 1990.
Copies of the comment letters and the City's responses to those
comments are set forth in Appendix B of this Resolution.
CONCLUSIONS
40. The City makes the following Conclusions:
a. The Final EIS was prepared in compliance with the
procedures of the Minnesota Environmental Policy Act
and Minn. Rules, parts 4410.0200 to 4410.6500
(December 19, 1988);
b. The Final EIS addresses the issues raised in
scoping so that all issues for which information can
be reasonably obtained have been analyzed; and
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10 C. The Final EIS provides responses to the
2166y
substantive comments received during the Draft EIS
review concerning issues raised in scoping.
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APPENDIX B TO RESOLUTION 90 - 194
On February 5, 1990, the City of Plymouth issued the
Bass Creek Business Park Final Environmental Impact Statement
(the "Final EIS"). The Final EIS updated certain sections of
the Bass Creek Business Park Draft Environmental Impact
Statement (the "Draft EIS") to respond to comments made during
the Draft EIS review period. Section 8.3A of the Final EIS
provided that written comments could be made on the Final EIS
at any time through February 19, 1990. The February 19
deadline was extended to February 20, 1990 to compensate for
the President's Day holiday on February 19, 1990.
The -following comment was received during the Final
EIS comment period:
A. City of Maple Grove, Randall Graves, Community
Development Director, letter to Blair Tremere dated
February 20, 1990.
In addition, the following two comments were received after the
close of the Final EIS comment period:
A. Suburban Hennepin Regional Park District, David
R. Weaver, Director, letter to Blair Tremere
dated February 16, 1990 (received by Plymouth on
February 21, 1990); and
B. Preliminary Metropolitan Council report dated
February 15, 1990, prepared by Richard E.
Thompson (facsimile received by Plymouth on
February 21, 1990), as amended by the
Metropolitan and Community Development Committee
and adopted by the Metropolitan Council on
February 22, 1990.
Copies of these comments are attached to this letter as
Exhibits A-1, A-2 and A-3.
The purpose of this letter is to summarize and address
the comments received during and after the Final EIS comment
period. References made herein to the "Project" shall refer to
the Bass Creek Business Park. The comments and recommended
responses are as follows:
1. Maple Grove requested coordination of the planning and
design efforts related to the compensatory wetland on the
Project site and the ponding basis and its outlet in the Vern
Donnay Eagle Lake Fifth Addition property during the planning
stages of both projects.
In response, coordination of planning efforts, as
suggested, has been initiated and is currently underway as
design solutions are evolving for both the Project and the Vern
Donnay property. Representatives of both Opus Corporation and
Vern Donnay have met and have maintained contact as solutions
for the compensatory wetland on the Project site and the
ponding basin on the Vern Donnay property have evolved. The
current direction of these efforts is toward a solution in
which each party benefits by the other's actions.
The plan under discussion would permit Vern Donnay to
place a portion of the southern ponding basin for Eagle Lake
Fifth Addition on Opus's property. This would include a berm
to deepen the pond, thus establishing normal and high water
pond elevations which would provide recharge for the adjacent
compensatory wetland being created by Opus.
This plan will be subject to approval by the Minnesota
Department of Natural Resources and the City of Plymouth.
Maple Grove's concerns will be addressed in this process.
2. Maple Grove commented that due to potential flooding
from the Siltation Basin #4 outlet on the Project site, Maple
Grove would prefer that outflow be restricted to the current 18
inch CMP rapacity with all emergency overflows of water beyond
the culvert's capacity being directed overland to the west,
bypassing the Maple Grove residential area.
In response, the referenced 18 inch CMP, which
provides drainage to the north from the area in which Siltation
Basin #4 is located, has never been considered as part of the
outlet for Siltation Basin #4. The intended direction for all
flows from Siltation Basin #4, both in a normal rainfall
occurrence and in an overflow situation, has been to the west
to Pike Lake, not north to the existing culvert. The
possibility of utilizing the existing culvert for some
conveyance from Siltation Basin #4 can be explored during the
final design of the planned storm water management system, but
in no case would it be expected that the current capacity would
be exceeded. Maple Grove's concerns will be addressed through
the City of Plymouth's required final site plan approval
processes.
2
. 3. Maple Grove's letter stated that the overland flow
velocities for the outlet of Siltation Basin #3 should not
exceed 1.5 feet per second unless additional channel
protections are planned.
In response, the final design for the outflow from
Siltation Basin #3 has not been completed at this time. It is
expected that all of the factors suggested would be taken into
account and incorporated into the final solution at the final
plat stage. Final engineering design and construction
documents for the drainage improvements will be developed at
that time. Maple Grove's concerns will be addressed through
the City of Plymouth's required final site plan approval
processes.
4. Maple Grove commented that inflows of water to
Siltation basin #4 from the parking area of Lot 5 on the
Project site and the sloping of the landscaped area of Lot 6
should be controlled to prevent excessive velocities down the
3:1 slope leading into the pond.
In response, the grading and drainage plans included
in the Final EIS are somewhat general in nature and reflect the
major systems required for the Project. Site specific details,
including the design of storm sewer systems for parking lots,
roof drainage, and landscaped areas (where necessary) have not
been developed. It would not be the intent, nor would it be
consistent with City of Plymouth poiicies, to direct runoff
from parking areas such as that on Lot 5 overland to the
siltation basins. Additional on-site storm sewer systems will
be designed at the site specific planning and design stages of
the Project. Maple Grove's concerns will be addressed through
the City of Plymouth's required final site plan approval
processes.
5. Maple Grove stated that if on-site siltation basins
are designed in accordance with the U.S. Environmental
Protection Agency's Nationwide Urban Runoff Program (NURP)
design criteria, they would require pool volume greater than or
equal to a 2.5 inch rainstorm under fully developed conditions
with a 25 percent increase in volume allowed for 25 years of
sediment accumulation. In addition, Maple Grove stated that
the mean depth of the permanent pool should be greater than or
equal to 4 feet and requested that hydrologic data be provided
to show that the basins meet the NURP design criteria for
phosphorus treatment. Maple Grove also requested additional
water quality calculations to support the 60% phosphorus
treatment statement in the Final EIS.
In response, the siltation basins that will be
constructed on the Project site will conform to NURP design
criteria. A listing of those criteria is attached hereto as
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Exhibit B. Exhibit C provides a comparison of the proposed
basins to NURP design criteria. All four proposed basins
either equal or exceed the permanent storage volume
requirements of NURP. The expected phosphorus removal
efficiencies of these basins exceeds 60 percent, as
demonstrated by the plots in the figure attached hereto as
Exhibit D. Maple Grove's concerns will be addressed through
the City of Plymouth's required final site plan approval
processes.
6. Finally, Maple Grove requested more detail as to where
and how berms would be constructed, especially with regard to
site limitations and visual impacts.
In response, the Final EIS references berming and
landscaping as elements to provide visual buffering along the
northern boundary. It was not the intent of those statements
to imply that both methods of controlling views would be
applied to all the areas where the transition from
non-residential to residential use occurs. In areas such as
the one referenced on Lots 5 and 6, where Siltation Basin #4
precludes berming, there would be a reliance on landscaping to
provide adequate screening. In other areas where there are
substantial elevational difference between residential and
non-residential uses, there would also be reliance primarily on
landscaping to provide screening. Berming as a means of visual
control would be incorporated only in those areas where
available space within the 100 foot buffer zone and relative
elevations of residential and non-residential uses would allow
for reasonable and sensible creation of berms.
The site plans and lot configurations along the
northern boundary are conceptual in nature, and were intended
to illustrate the maximum intended development intensity for
study in the EIS. It is very likely that the ultimate site
planning and configuration of building, parking, and landscaped
areas, and even grade relationships, may vary from those
illustrated when the site actually develops. The objectives
and parameters of visual control of the area have been
established in the planning and approvals to date. The
responsibility for successful application and implementation of
visual control rests with Opus Corporation.and the City of
Plymouth as part of the final site plan design review and
approval process as described in the Final EIS. MPiele Grove's
concerns will be addressed through the City of Pi.ymouth's
required final site plan approval processes.
The Suburban Hennepin Regional Park District
("Hennepin Parks") comment letter states that Hennepin Parks
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disagrees that the estimated phosphorus loading to Pike and
Eagle Lakes resulting from the Project is an unavoidable impact
of the proposed development. Hennepin Park believes it is
feasible to route the discharge from Siltation Basin #3 east
into either Siltation Basin #1 or Siltation Basin #2, thus
removing 59 acres from the Pike Lake drainage area and reducing
the Project -generated phosphorus load to Pike and Eagle Lakes
by approximately 85%. Hennepin Parks claims that because
rivers are more capable of assimilating nutrients than lakes,
if the majority of the storm water is routed east into
Siltation Basin #1 or #2 and is then discharged into Bass Creek
(and eventually the Mississippi River), the impacts of the
Project on water quality would be minimized. The Hennepin
Parks comment letter expresses the additional concern that
although the -Project's impacts on Pike and Eagle Lakes are
significant, the Project represents only five percent of the
watershed area and that, with 60% of the watershed yet to be
developed, the increase in phosphorus loading from future
developments could potentially make Eagle and Pike Lakes
"virtually unsuitable for recreational use."
In response, it would be technically feasible to
install a pipe to route discharge from Siltation Basin #3 to
Siltation Basin #1 or #2, and eventually into Bass Creek,
although, as discussed below, the effect of this diversion
would be to shift the impacts of phosphorus loading from Pike
and Eagle Lakes to Palmer Lake in Brooklyn Center.
City of Plymouth engineering standards specify a
minimum pipe size of 15" for public drainage improvements. A
15" pipe would provide more than adequate capacity to route the
2.5" rainfall which is the basis of the Final EIS water quality
analysis from Siltation Basin #3. It is our understanding that
a 2.5" rainfall is representative of the frequent rainfall
condition which transmits pollutants. By way of comparison,
the City's storm sewer design criteria for establishing pipe
sizes is a 5 year frequency storm of 3.5".
Installation of a 15" pipe from the wetland near
Siltation Basin #3 to the large wetland on the east side of the
Project site would cost approximately $100,000. In order to
minimize pipe depth and maximize site flexibility, the pipe
would be routed along the cul-de-sac in the northern portion of
the Project site, paralleling the storm sewer which will empty
into Siltation Basin #2. The pipe would not route storm water
to Siltation Basin #2, but rather would outlet directly into
the major wetland. Cost for the approximately 2,200 l.f. of
15" pipe and attendant structures is estimated at $75,000.
Modifications to the previously designed system necessary to
resolve conflicts between this pipe and a segment of 59" pipe
in the previous drainage plan are estimated to add another
$25,000 to the cost. The solution suggested by Hennepin Parks
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is thus technically feasible at a cost of approximately $100,000.
If this solution were pursued, no runoff from a rainfall of lesser
intensity than something in excess of a 100 year event would reach
Pike Lake.
If the effluent from runnoff detention basin B-3 were
diverted from Pike Lake to Bass Creek instead, there would be a net
4 kg/yr decrease in phosphorus loading to Pike Lake. This would
result in very slight water quality improvements in Pike Lake as
indicated in Table 1. The diversion would not significantly affect
current Eagle Lake water quality. Phosphorus loading to Bass Creek
would increase by 32.5 kg per year as a result of this diversion.
The latter loading estimate assumes 60% phosphorus removal by
detemion basin B-3, but no further removal by the Wetlands G (572W)
or A (571W)."
TABLE 1: ESTIMATED LAKE WATER QUALITY; BEFORE AND AFTER BASS CREEK
BUSINESS PARK DEVELOPMENT, ASSUMING EFFLUENT FROM
DETENTION BASIN B-3 IS DIVERTED FROM PIKE LAKE TO BASS
CREEK INSTEAD
Parameter Pike Lake Eagle Lake
(units) Current Future Current Future
Total phosphorus (mg/L) 50 49 35 35
Chlorophyll a (mg/L) 28 27 19 19
Secchi disc transparency
(m) 1.93 1.94 2.37 2.37
Bluegreen algal dominance
M 52 51 42 42
Algal bloom frequency
(% of summer with Ch1
X30 mg/L) ca. 70 ca. 69 ca. 20 ca. 20
Source: Barr Engineering, February, 1990
Some small amounts of additional particulate
phosphorus removal may occur in the Wetland A (571W) adjacent
to detention basins B-1 and B-2. Most particulates should be
removed by detention basin B-3, however, and only soluble
(dissolved) phosphorus will be discharged to the wetland. This
soluble phosphorus will be detained in the wetland through
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biological uptake during the growing season, but subsequently
released when wetland plants die and decompose. The released
phosphorus will then be exported from Wetland A (571W) via Bass
Creek and Shingle Creek to Palmer Lake. Wetlands will change
the temporal movement of dissolved phosphorus through the
system, but will only retain a small fraction of the total
annual phosphorus load.
The City of Plymouth will require the project proposer
to further study the alternative solutions that may be
available to further decrease the introduction of phosphorus to
Pike Lake and other water bodies that are downstream from this
project. Those alternatives would include review of the
concept of physically diverting storm water from the Pike Lake
Drainage District; investigation of measures to physically
reduce the amount of phosphorus introduced to storm water
drainage from the site through control of fertilization
activities on-site; and/or combinations of these alternatives
for the reduction of phosphorus levels to Pike Lake by other
water bodies.
M ... a •_� -..
The Metropolitan Council report recognizes that the
water quality mitigation practices plan for the Project are the
"best practical treatment technologies" available. However,
the Metropolitan Council disagrees that the water quality
impacts on Eagle Lake are unavoidable. The Metropolitan
Council report recommends that mitigation of Project impacts
through off-site treatment or in -lakes treatment be made the
responsibility of the City of Plymouth and the Shingle Creek
Watershed Management Organization because "the developer is
doing as much as is reasonably possible on the site." The
report also states tha';. the impacts of the Project must be
assessed in the context of the cumulative effect of this and
future development of the watershed. As adopted by the
Metropolitan Council on February 22, 1990, the report concludes
that the Project should be approved and that the City and
Shingle Creek Watershed Management Organization should work to
implement off-site treatment facilities to address the impacts
of this Project and future developments.
The City of Plymouth recognizes that a portion of the
Drainage District that drains naturally to Pike Lake is located
within the City of Plymouth. The balance of the drainage area
is located in other communities. The City of Plymouth also
recognizes the fact that the entire drainage area for Pike Lake
is in the jurisdiction of the Shingle Creek Watershed
District. Shingle Creek has adopted surface water quality
standards which are met or exceeded by the Storm Water Drainage
Management Plan proposed for this project.
Consistent with established procedures with regard to
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. storm water drainage planning, the City of Plymouth continues
to support the efforts of the Shingle Creek Watershed District,
and the other Watershed Districts serving the City of
Plymouth. The City of Plymouth will continue to insist that
projects developed within the City be responsive to the
standards established by the Watershed Districts with respect
to storm water drainage -- including quality.
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