2001-10-22Aeenda
Mound City Council Workshop
CSAH 15 and Related Project Funding
October 22, 2001
7:00 PM
Call meeting to order <~ ~:t~$' ~ ~ 16 ~uL~
Review project components and costs
3. Review project sources
Se
Review gap between cost and identified sources
Discuss funding options and impacts
Discuss decision time fram
Adjourn meeting ~ ~ m~ ~
EHLERS
& ASSOCIATES INC
TO:
From:
Subject:
Date:
Kandis Hanson, City Manager
Jim Prosser, Financial Advisor
CSAH 15 Funding Options
October 15, 2001
Ehlers & Associates has been asked to prepare a summary of the estimated costs associated with CSAH
15 and related downtown improvements. Hoisington-Koegler Group, Inc., MRFA and Kennedy Graven
have provided estimates of these costs. The attached spreadsheet reflects our best estimate of City costs
related to this project. The left hand columns on the spreadsheet organize the "uses" or estimated
expenditures. The right hand columns reflect the potential funding sources to pay project costs.
The attached spreadsheet demonstrates that this is a very complex project. It is important that the City
develops a clear understanding of project related costs and financing options in order to make decisions
regarding this project. For that reason the spreadsheet generally reflects prospective expenses and not
previously incurred expenses.
As shown, the total project costs are estimated at $12,783,500. Fortunately, most of the project cost will
be paid by outside sources as shown below.
Funding Source Summary
Non designated 3,834,676 30%
Federal Grant* 640,000 5%
Reserved City Funds 2,266,250 18%
County 3,620,000 28%
Other agency payments 1,229,000 10%
Developer assessed 1,193,924 9%
Total 12,783,850 100%
* Requires 20% City match
The full listing for each of these sources is found on the attached spread sheet. Most of the outside
funding sources will need to be secured by agency agreement prior to spending for that particular project.
Agreements will be needed for Hennepin County, Metropolitan Council Waste Water, Xcel Energy and
Metro Transit.
The City reserved funding sources include, primarily, monies set aside for this specific project. Also
shown is a summary of expected land sale proceeds in the amount of $580,000.
The difference between identified sources and total project cost is shown as "non designated" and is
estimated at approximately $3.8 million. It will be necessary to identify a funding source for this amount
for the project to proceed. While a variety of options are technically available most are not practi,cal.
The recommended financing options is the issuance of General Obligation Improvement Bonds. These
LEADERS IN PUBLIC FINANCE ~
3060 Centre Pointe Drive 651.697.8534 fax 651.697.8555
Roseville, MN 55113-1105 diana@ehlers-inc.com
Page 2
October 17, 2001
bonds would be issued as part of the road improvement and would include the amount to be assessed and
paid for by the developers (estimated at $1.2 million). The total amount of the issue would be
approximately $5 million. Of that amount $1.2 million would be paid by assessments (secured through
development agreements). The balance of $3.8 million would be paid from the City's general debt levy
assessed against all property within the City. The attached exhibit B shows the annual tax levy required
to support this debt issue. This amount could be reduced by up to $110,000 annually by use o£a portion
of the Municipal State Aid (MSA) capital funds allocated to the City annually. This represents 50 % of
the total allocation for the City. State law permits use of funds for this purpose.
The tax impact for these options is shown on the attached Exhibit B. At the time the City sells the various
remnant parcels these funds could be used to reduce the tax levy or reimburse the capital fund for prior
project expenditures.
C:\W1NDOWS\Temporary lntemet Files\Content. IE5\496BCDEF~l 0.15.10 funding memo .wpd
City of Mound
Mound Visions
Redevelopment-Related Public Expenditures
October 16, 2001
Uses Sources
Amount Amount
Lost Lake Greenway
Construction 1,100,000 Reserved City Funds ~ 450,000
Design/Engineering/Admin. 65,000 TEA 21 520,000
Non Designated 195,000
subtotal 1,165, 000 subtotal ~, ~ 65, 000
County Road 15 Relocation
ROW Acquisition 4,300,000 County 50/50 ROW cost split 2,150,000
Construction _ .~ ~ ~,~m~ ~ ~ 2,100,000 County 70/30 construction split 1,470,000
Watermain Replacement ~ 100,000 Water fund 100,000
Agency Coordination 50,000 MSA fund balance (1/31/02) 900,000
Non Designated 1,930,000
subtotal 6,550,000 subtotal 6, 550, 000
CSAH15 Streetscape (areas not linked to redevelopment projects listed below) and Park & Ride Lot
.~~~-"~ Streetscape Construction ~/.,'~'~'Q~-~-~x~b~ ~0,000 TEA 21 ~'~'~ 68,000
Park & Ride Lot Construction J 85,000 Xcel ~ --c/.~ ~ 54,000
Park & Ride Lot Site Amenities 25,000 MetroTransit 120,000
Design/Engineering/Admin. 138,600
Bus Shelter Construction 120,000 Non Designated 766,600
subtotal 1,028, 600 subtotal 1,028, 600
Auditors Road Completion
Post Office Demolition 70,000
Street Construction 250,000
Public Contrib to Auditors Storm Pond 25,000
PO Demolition Eng/Admin 9,800
Construction Eng/Admin 62,500 Non designated 417,300
subtotal 417, 300 subtotal 417, 300
Regional Storrnwater Pond
Appraisals 10,000 MCWD payment 190,000
Environmental Testing 15,000 Stormwater Bond Proceeds 200,000
Property Acquisition 185,000
Pond Construction 190,000
Agency Coordination 15,000
Contamination Contingency 50,000 Non Designated 75,000
subtotal 465, 000 subtotal 465, 000
Well Closure/Relocation
Relocate/Restore Pump House 125,000 Water Fund 125,000
Abandon Existing Well 10,000 Water Bond Proceeds 341,250
Drill New Well 265,000
New Well Dsn/Eng/Admin. 66,250 Non Designated
subtotal 466,250 subtotal 466,250
Lift Station Relocation ~ 4{u~.~ J~O ~r~.~L-~c~.~R.~t~ ,t~% --
Appraisals---- ~J 5,000 Metro Waste 250,000
Environmental Testing ~.~- ~ 12,000 Developer Payment - Assessed 212,000
Property Acquisition ~t ~1~10¢~c¢h ~ 115,000
Construction 250,000
Agency Coordination 10,000
Easement Contingency 20,000
Contamination Contingency 50,000 Non Designated
subtotal 462, 000 .,, subtotal 462, 000
Apraisals Xcel franchise (ratepayers) 525,000
Environmental Testing 20,000 Land sale proceeds 90,000
Substation Land Acquisition 90,000
Line Relocation 500,000
Agency Coordination 20,000
Contamination Contingency 25,000
Non Designated 50,000
subtotal 665, 000 subtotal 665, 000
Xcel Distribution Line Relocation
Agency Coordination 10,000 Non Designated 10,000
subtotal 10, 000 subtotal 10, 000
Prepared by Ehlers & Associates, Inc. Page I of 3
City of Mound
Mound Visions
Redevelopment. Related Public Expenditures
October 16, 2001
Uses Sources
Items Related to Langdon District Redev
Utility Improvements 40,000 Developer Payment - Assessed ) 230,100
Commerce Boulevard Streetscape 125,000
Commerce Blvd On-Street Parking 30,000
Legal Consult 15,000
Planning Consult 6,000
Redevelopment Consult 10,000 Non Designated 31,000
subtotal 261,1 O0 subtotal 261,100
Items Related to Auditors District Redev
Commerce Blvd On-Street Parking 30,000
Design/Engineering/Admin. 72,900
Legal Consult 15,000
Planning Consult 6,000
Redevelopment Consult 10,000
Non Designated 31,000
subtotal 508, 900 subtotal 508, go0
Items Related to MetroPlalns Redev
CSAH 15 Streetscape 64,300 Developer Payment - Assessed 214,524
Commerce Boulevard Streetscape 102,500
Turn-lane on CSAH 15 15,000
Design/Engineering/Ad min. 32,724
Legal Consult 6,000
Planning Consult 3,000
Redevelopment Consult 3,000 Non designated 12,000
subtotal 226, 524 subtotal 226, 524
Items Related to True Value District Redev
CSAH 15 Streetscape 132,200 TEA 21 32,000
Commerce Boulevard Streetscape 55,000 HRA Fund Balance 150,000
Commerce Blvd On-Street Parking 6,000 Assessed to owners 12,200
Municipal Parking Lot ~- 150,000
Desig n/Engineering/Admin. 61,776
Contamination Contingency 50,000
Legal Consult 6,000
Planning Consult 4,000
Redevelopment Consult 4,000
Non designated 274,776
subtotal 468, 976 subtotal 468, 976
Items Related to Post Office Development
CSAH 15 Streetscape 40,000 ~ Assessed to owners 47,200
Design/Engineering/Admin. 7,200
Legal Consult 5,000
Planning Consult 1,000
Redevelopment Consult 1,000 Non designated 7,000
subtotal 54, 200 subtotal 54, 200
Misc Mound Visions Coordination
Legal Consult 5,000
Planning Consult 20,000
Redevelopment Consult 10,000 Non designated 35,000
subtotal 35,000 subtotal 35~ 000
Budget Total $ 12,783,850 $ ~2,783,850
Prepared by Ehlem & Associates, Inc. Page 2 of 3
Fundinp fiource fiummary
Non designated
TEA 21
Reserved City Funds
County 50/50 ROW cost split
County 70/30 construction split
Water fund
MSA fund balance (1/31/02)
Xcel
MetroTransit
Xcel franchise (ratepayers)
Stormwater Bond Proceeds
Water Bond Proceeds
Metro Waste
MCVVD Land payment
Developer Payment - Assessed
Land sale proceeds - Xcel
HRA Fund Balance
Assessed to owners
Financing Options for Non Designated
Increase HRA Levy - annual
TIFAdministrative Bond - MetroPlains
MSA Bond
Land Sale Proceeds
Special Assessment - General Levy Portion
TIF Bonds
City of Mound
Mound Visions
Redevelopment-Related Public Expenditures
Oc' ober 16, 2001
3,834,67E
640,000
450,000
2,150,000
1,470,000
225,000
900,000
54,OOO
120,000
525,000
200,000
341,250
250,000
190,000
1,134,524
90,000
150,000
59,400
1~78~850
30,000
200,000
2,200,000
580,000
4000000+
To be determined
Potential Land ,%re Proceeds
Longpro Property
Mueller Lansing remnent
Post Office
Total
Notes
Pay for onging administrative costs
Schedule uncertain
Commits 1/2 of future construction funds
Sale date uncertain
240,000
120,000
580,000
Requires 20% assessment -
Requires 20% tax increment payment
Prepared by Ehlers & Associates, Inc. Page 3 of 3
City of Mound, MN
Analysis of Tax Impact for Potential Bond Issue
October 15, 2001
Bond Issue Size
Est. Tax Capacity Rates (debt only)*
Net Tax Capacity
Annual Levy Increase
Increase in Tax Rate
3,905,000.00
6,383,825.00
227,000.00
3.56
Type of Property
Residential
Homestead
Commercial/
Industrial
Taxable
Market Value
$8O,OOO
100,000
125,000
150,000
175,000
200,000
250,000
300,000
350,000
$50,000
100,000
200,000
300,000
500,000
Estimated Increase in Taxes
for Debt Service Only*
$28
36
44
53
62
71
89
107
124
$27
53
116
187
329
Prepared by Ehlers & Associates, Inc. 10/18/2001
Option One
City of Mound, MN
Debt Service Schedule G.O. Improvement Bonds, Series 2002
Par Amount of Bonds
TOTAL SOURCES
Total Underwdter's Discount (1.500%)
Costs of Issuance
Deposit to Project Construction Fund
Rounding Amount
TOTAL USES
Date Principal Rate Interest
2/1/2002
2/1/2003 125,000 2.95%
2/1/2004 130,000 3.35%
2/1/2005 135,000 3.60%
2/1/2006 140,000 3.85%
2/1/2007 145,000 4.10%
2/1/2008 150,000 4.30%
2/1/2009 160,000 4.45%
2/1/2010 165,000 4.55%
2/1/2011 170,000 4.65%
2/1/2012 180,000 4.80%
2/1/2013 190,000 4.95%
2/1/2014 200,000 5.10%
2/1/2015 210,000 5.20 %
2/1/2016 220,000 5.30%
2/1/2017 230,000 5.40%
2/1/2018 245,000 5.50%
2/1/2019 255,000 5.55%
2/1/2020 270,000 5.60%
2/1/2021 285,000 5.65%
2/1/2022 300,000 5.70%
3,905,000
3,905,000
58,575
45,000
3,800,000
1,425
3,905,000
Total
P&I
P&I
+ 5.00%
MSA
192 415
188 728
184373
179 513
174 123
168 178
161 728
154608
147 100
139 195
130 555
121 150
110,950
100,030
88,370
75,950
62,475
48,323
33,203
17,100
317,415
318,728
319,373
319,513
319,123
318,178
321,728
319,608
317,100
319,195
320,555
321,150
320,950
320,030
318,370
320,950
317,475
318,323
318,203
317,100
333 286
334 664
335 341
335 488
335 079
334 086
337 814
335 588
332 955
335 155
336 583
337 208
336 998
336 032
334 289
336 998
333 349
334 239
334 113
33; 955
/
/
3,905,000
(110,000
(110,000
(110,000
(110,000
(110,000
(110,000
(110,000
(110,000
(110,000
(110,000
(110,000
(110,000
(11O,OO0
(110,000
(110,000
(110,000
(110,000
(110,000
(110,0OO
(110,000
.et
Debt
Service
223 286
224 864
225 341
225 488
225 079
224 086
227 814
225 588
222 955
225 155
226 583
227 208
226 998
226 032
224 289
226 998
223 349
224 239
224 113
222 955
2,478,063 6,383,063 6,702,216 (2,200,000) 4,502,216
Prepared by Ehlers & Associates, Inc. 10/18/2001
Hennepin County Transportation Department
1600 Prairie Drive
Medina, MN 55340-5421
October 17, 2001
763-745-7500, Phone
763-478-4000, FAX
763-478-4030, TDD
www. co.hennepin.mn.us
Mr. Jeffrey J. Roos, P.E.
McCombs Frank Roos Associates, Inc.
15050 23rd Avenue North
Plymouth MN 55447
RE: CSAHI5 Relocation in Mound
Please be advised the county will acquire right of way necessary for relocation of CSAH 15 in
downtown Mound under Project No. 9417. The county intends to relocate CSAH 15 in 2003, with
work to begin as early as possible in the construction season.
As you are aware, the city intends to acquire certain properties for redevelopment purposes. Portions
of those properties are also required for the CSAH 15 relocation project. In such instances the county
would reimburse the city for its prorata share of the property acquisition costs (i.e. purchase price and
appraisal costs). I have asked Brad Moe, Real Estate Division Manager, to contact Kandis Hanson to
confirm how such cost splits will occur.
Regarding the temporary realignment of CSAH 15 along local streets to accommodate redevelopment
activities, the county is willing to work with the city to bring about the necessary changes.
Accordingly, I have asked Greg Chock, Operations Division Engineer, to meet with John Cameron to
determine the scope of work necessary to prepare the local streets for the increased traffic volumes
which normally traverse CSAH 15.
Sincerely,
James N. Grebe, P.E.
Director, Transportation Department
JNG/cu
CCi
Kandis Hanson
John Cameron
Brad Moe
Greg Chock
Gary Erickson
An Equal Opportunity Employer Recycled Paper
5341 Maywood Road
Mound, MN 55364
(952) 472~3190
City Council Workshop Agenda
Monday, October 22, 2001, 7:00 PM
ge
Project Overview
A. Conditional Approval of Mound Surface Water Management Plan by MCWD -
May 10, 2001
B. 180-day timeline for execution of joint cooperative agreement
C. Ordinance amendment(s) and timeframe for adoption
Discussion Items - Implementation of Mound Surface Water Management Plan
A. Preparation of MCWD Generation III Plan
B. Proposed buffer increase
C. Proposed MCWD Rule M - implementation of wetland buffer for lakes and
streams
D. Possible impact(s) on redevelopment activities within the City of Mound
E. Status of wetlands functions and values report - Hennepin County Conservation
District
Benefit and Value of Wetland Buffers - Review of Teclmical Information
Application of We0and Buffer(s) - City of Mound Projects
Questions and Comments
5341 M~y~ood Road
Mound, MN 55364
(952) 472-3190
Memorandum
To:
From:
Date:
Re:
Honorable Mayor and City Council
Sarah Smith, Community Development Director
10/18/2001
Surface Water Management Plan / Cooperative Agreement
Background
As the City Council is aware, the MCWD approved the Mound Surface Water Management Plan
(SWMP) on May 10, 2001 subject to a number of conditions including the execution of a
cooperative agreement between the MCWD and the City of Mound within six-months following
the Plan's approval. At its June 26, 2001 meeting the City Council considered and subsequently
tabled the cooperative agreement due to several concerns expressed by members of the Council
regarding the adoption of wetland buffer and the types of activities that trigger the implementation
of a buffer strip.
Project Update
City stuff has met on several occasions to discuss the status of the Plan and cooperative agreement
and has also met with Glenda Spiotta of the MCWD regarding Mound's Plan as well as the status
of the wetlands functions and values report from the Hennepin County Conservation District
which is pending completion.
Members of the City Council are advised that there are a number of substantial issues associated
with the SWMP which merit immediate discussion including, but not limited to, the following
items:
It is City staff's understanding that the MCWD has begun preparation of its Generation III
Plan which may include stricter rules than its current Plan.
There are significant benefits for the City of Mound to take over responsibility for surface
water management including, but not limited to, permitting issues associated with the
pending County Road 15 project as well as downtown redevelopment activities.
Due to the existing MCWD role regarding wetland buffers, members of the City Council
are advised that Mound's Plan and/or ordinance amendments will not be approved
withoUt the inclusion of a wetland buffer requirement
City staff has learned that the proposal from the MCWD to increase the wetland buffer
standards has once again resurfaced and may be moving forward within the next few
month(s). In the event the cooperative agreement between the City of Mound and the
MCWD is not approved prior to the six-month deadline, the possibility exists that
Mound's Plan could be subject to the proposed new rules effective immediately in the
event they are approved. Conversely, if Mound's Plan is already formally approved via
execution of the joint cooperative agreement, it is likely we would be "grandfathered in"
until such time as the Generation III Plan would be approved by the MCWD.
The MCWD has also proposed new buffering rules 0q~le M) that would be applied to
lakes and streams in addition to designated wetlands.
Wetland Buffers - Technical Information
For your review and information, a number of technical documents have been included as
attachments to help explain the value and benefit of establishing a wetland buffer. Specifically,
please refer to the memorandum and materials that have been provided by City Planner Loren
Gordon.
· Memorandum from City Planner Loren Gordon dated October 15, 2001
February 12, 2001 draft letter from Peterson Environmental - City of Minnesota
Wetland Ordinance
· Summary of Wetland Buffer Zone Research and Buffer Recommendations - HKGI
for the City of Minnetonka dated January 15, 2001
· City of Wayzata Stormwater Management Plan dated July 2000 - pages 4-13 (wetland
buffer benefits)
The Role of Natural Buffer Strips in Controlling Phosphorous and Sediment Runoff-
Chet Rock
Application of the Wetland Buffer - City of Mound Project
A number of maps of recent projects have been included to help demonstrate how the wetland
buffer would apply in the City of Mound.
Staff Participation
City stuff, including Dan Parks, Loren Gordon, John Dean and myself will be present at the
workshop to review the status of the Mound Surface Water Management Plan and cooperative
agreement with members of the City Council.
· Parle 2
Supplemental Information
· Letter to MCWD dated October 16, 2001 to Ms. Glenda Spiotta
· Letter to City of Mound dated October 9, 2001 to Ms. Kandis Hanson
· Resolution # 06-2001 from MCWD Board of Managers
· Cooperative Agreement- draft
· MCWD Handout - Information about MCWD Rules and Permit Applicability
· Proposed Rule M - Lake Stream and Wetland Buffer (draft)
· Page 3
MEMORANDUM
Hoisington Koegler Group Inc.
mfl
To:
From:
Date:
Subject:
Sarah Smith, Community Development Director
Loren Gordon, City Planner
October 15, 2001
Background Information on Wetland Buffers
I have assembled some background information on wetland buffers for the City Council and Staff
to assist with discussion involving the application of wetland buffers in development projects.
The purpose of this information is to provide a level of technical information on the effectiveness
of wetland buffers. Included is information regarding wetland buffers our firm recently completed
a similar project for the City of Minnetonka. As a part of our project team, Peterson
Environmental Consulting, performed a literature review on the effectiveness of wetland buffers in
reducing phosphorous levels on wetlands and water bodies. The letter from Peterson
Environmental dated February 12th, provides their observations and recommendations on a draft
wetland ordinance. Also in the information from Peterson is a draft report titled, "Summary of
Wetland Buffer Zone Research and Buffer Recommendations," prepared for the City of
Minnetonka dated January 15, 2001 which was used as a basis for their wetland ordinance.
You will also find graphics that show development projects in Mound and are intended to
illustrate how Staff would apply wetland buffers per our proposed ordinance language. That
language is as follows:
Wetland Buffers. When a site is proposed to develop or redevelop in a manner that
requires a Major Subdivision, a natural wetland buffer shall be provided. The minimum
buffer width along a wetland or replacement wetland within each lot may range fi.om 50 to
150 percent of the requirement in order to provide flexibility and encourage a natural
appearance.
Still at issue with the MCWD is the idea of buffer averaging. Although most research on buffers
suggests averaging is a widely embraced practice, the MCWD is requesting the language we have
proposed be removed. Staff believes this is an important element that should be included in our
ordinance.
A second note with the proposed language above is the use of the term "Major Subdivision"
might be modified to reflect the current MCWD language which is "Development" in order to
provide flexibility. Staff interpretation of development would be a major subdivision proposal.
123 North Third Street, Suite 100, Minneapolis, Minnesota 55401
(612) 338-0800 Fax(612) 338-6838
Wetland Buffers -Technical Information
February 12, 2001
Mr. Loren Gordon
Hoisington Koegler Group
123 North Third Street, Suite 100
Minneapolis, Minnesota 55401
Mr. Tom Goodmm
City of Minnetonka
14600 Minnetonka Boulevard
Mirmetonka, Minnesota 55345
Subject:
Observations & Recommendations
Draft Minnetonka Wetland Ordinance
PEC Project No. 2000-013
Dear Loren and Tom:
With this letter, we are providing our observations and recommendations regarding the draft
Minnetonka Wetland Ordinance Amendment dated August 30, 1999. In our comments we will
refer primarily to the draft ordinance amendment and to some degree the accompanying staff
repo.rt of the same date. We are also providing as supporting material an updated review of
scientific literature on wetland buffer zone effectiveness. Our comments are as follows:
Ordinance' Subdivision 2 (a): Type 1 wetlands
We fully concur that Type 1 wetlands be included in the City's ordinance. By being consistent
with state and federal agencies on what is being regulated, the City is streamlining the regulatory
process. While some might argue that many Type 1 wetlands are degraded and of poor quality,
this issue is best dealt with by varying buffer requirements according to the actual character of
the individual wetland.
Ordinance Subdivision 2 (a): Lakes and Streams Versus Wetlands
There has been some question whether lakes and streams should be distinguished from wetlands
or whether they should be covered by the City's wetland ordinance. Under the classification
system set forth in "Classification of Wetlands and Deepwater Habitats of the United States"
(Cowardin et al.; FWS/OBS Publication 79/31), lakes (lacustrine systems) are distinguished from
· · 'Comments/Recommendations on Draft Mirmetonka Wetland Ordinance
, ,February 12, 2001
Page 2
PEC Project No. 2000-013
wetlands. Lakes are waterbodies that are more than two meters (6.56 feet) deep while wetland
have hydrologic regimes ranging from surface saturation up to two meters of inundation.
Similarly, the beds of rivers and streams are classified as riparian systems under the Cowardin
system, while adjacent floodplain wetlands are considered palustrine systems.
Since lakes and major watercourses are already subject to their own protections under the City's
shoreland Ordinance, it probably would minimize confusion to continue distinguishing these
waterbodies from wetlands regulable under the wetland ordinance. We believe that waterbodies
having shoreland designations should be excluded from the wetland ordinance and protected via
the shoreland ordinance. Wetlands that are adjacent to lakes and streams should, however, still
be covered by the wetland ordinance. The city seems to have akeady included sufficient
flexibility in its draft wetland ordinance to allow the waiver of buffer reqirements in such areas if
there is a good reason to do so. We anticipate that in the portion of Minnetonka falling within
the HCD's wetland inventory of the MCWD, wetlands adjacent to lakes and streams will be
mapped separately from lake basins and streambeds.
If the City also wishes to extend to non-wetland lakeshore areas some of the protections afforded
to wetlands, there could be some cross-referencing between the two ordinances. However, In a
relatively fully developed city like Minnetonka, we would expect significant logistic problems in
extending wetland buffer requirements to non-wetland lakeshores across the board. In most
cases, riparian lot owners will already have such lakeshore areas in some type of use that they
will want to continue. Also, the ability to use those areas as part of the rear yard or for recreation
is likely to be a significant factor in the value of the lakeshore property.
Ordinance Subdivision 3: Common Jurisdictional Boundaries
As with item 1, making the City of Minnetonka's jurisdictional wetland boundaries consistent
with state and federal agencies will greatly streamline the regulatory process for both City staff
and applicants. In our practice, we have encountered problems in trying to reconcile the City's
elevation-based boundaries With wetland delineations done according to the 1987 Corps of
Engineers Wetlands Delineation Manual (hereafter referred to as the 1987 Manual). In one case,
the elevation of the City wetland boundary actually went through the middle of a resident's
garage on the other end of the wetland complex. The elevations of wetland boundaries often
vary due to varying hydrologic characteristics across a wetland or wetland complex. Strict use of
a specific contour will almost always result in errors on one side of the line or the other.
The proposed change is consistent with what is occurring at the state level. Elimination of
multiple jurisdictional standards and boundaries was an objective of both the 1996 amendments
to the Wetland Conservation Act (WCA) and Senate File 83, which the legislature passed last
session. Before 1996, the WCA required the use of the 1989 Federal Manual for Identifying and
Delineation Jurisdictional Wetlands, while the Corps of Engineers had gone back to its 1987
Manual. With the 1996 amendments, the WCA requires the same manual as the Corps of
Engineers, including any ongoing amendments. Senate File 83 brings the Minnesota DNR into
the fold as well. With the passage of Senate File 83, the DNR will no longer be using ordinary
' Comments/Recommendations on Draft Mirmetonka Wetland Ordinance
February 12, 2001
Page 3
PEC Project No. 2000-013
high water levels to define their jurisdictional limits on Public Waters Wetlands (i.e. wetlands
with a "W" suffix on the Public Waters Inventory). The 1987 Corps of Engineers Wetlands
Delineation Manual will now be used by all state and federal agencies in Minnesota to define
wetland boundaries. With the proposed ordinance changes, the City of Minnetonka will be
consistent with all of these agencies as well.
The staff report suggests that the current City delineations continue to be relied upon for minor
projects if the applicant hasn't provided one. We would recommend against this. If the use of
the City's elevation-based boundary resulted in unintended impacts to wetlands regulated under
state and federal programs, it could expose the applicant to potential enforcement action. It
would be less problematic to avoid the potential for confusion altogether and to use one common
boundary for all programs.
· Ordinance Subdivision 3: Wetland Contours Versus Wetland Maps
Given that the City's jurisdiction would no longer be def'med by contours, we suggest the
existing wetland inventory maps be revised to show the approximate 1987 Manual boundaries of
all wetlands regardless of type or elevation. This is What has been done., on other successful
inventories we are aware of. The ordinance could then state that the boundaries shown on the
maps are only approximate. Actual jurisdictional status determinations and wetland delineations
would then be required on any site to which the ordinance would potentially apply. If the
contour-based maps are retained, they will generate ongoing confusion for applicants. Also, if
WCA/Corps wetlands are potentially involved, a delineation using the 1987 Manual will be
required anyway. It is our understanding that the Hennepin Conservation District is currently
working on an inventory of all wetlands within the Minnehaha Creek Watershed District. Since
much of Minnetonka will be encompassed by this inventory, it may be to the city's advantage to
participate in it.
It is our understanding that the existing wetland overlay district requires the rezoning of wetland
areas impacted by development and any mitigation areas that are created~ Given the substantial
advances that have been made in wetland regulation since the current ordinance was adopted, we
suggest that a wetland overlay district may no longer be necessary for several reasons:
(1)
All wetlands in Minnetonka are protected by the Wetland Conservation Act (WCA) for
which the City of Minnetonka serves as the responsible Local Government Unit (LGU).
Except for activities covered by WCA exemptions, no wetland in Minnetonka can be drained
or filled without approval of a WCA Wetland Replacement Plan. Wetlands that are
created/restored as mitigation under the WCA must be protected by permanent conservation
easements or the equivalent to ensure their long-term viability. The amended ordinance
would extend this protection to buffers as well. By providing strict "sequencing" procedures
and affording perpetual protection of mitigation and buffer areas, the combination of the
WCA and the amended ordinance would obviate the ongoing need for the Minnetonka
wetland overlay district.
"Comments/Recommendations on Draft Minnetonka Wetland Ordinance
February 12, 2001
l~age 4
PEC Project No. 2000-013
(2) Requiring wetland impact and mitigation areas to be rezoned imposes a substantial burden on
both applicants and City staff without a concomitant wetland protection benefit.
(3) Retaining the overlay district requires the perpetuation of the existing wetland contour maps.
Wetland boundaries based on the 1987 Wetlands Delineation Manual cannot be as readily
used to define an overlay'district since they cannot be described either by a comour or by
metes and bounds.
Ordinance Subdivision 7(a)(5): Wetland Buffer Monumentation
We strongly support the use of buffer monumentation. We have seen problems a number of
times where monuments were not installed before lots were sold or developed. Even when the
buffer is within an easement recorded on a deed, we have seen lot purchasers claim ignorance
and pursue litigation over their inability to make a buffer part of their lawn..It might be
advantageous to the city to standardize the design and content of buffer monument signage. We
believe the'City of Chanhassen requires the use of city-designed monument signs that the city
sells at a nominal fee to developers. These signs would be a good template for use in the City of
Minnetonka.
Ordinance Subdivision 7(b): Wetland Buffer Widths & Treatments
As described in our updated literature review, wetland buffers do provide .significant benefits in
removing nutrients and sediment from surface runoff entering a wetland. The need for buffers is
greatest in newly developing areas or on farmland, where sediment and nutrients are liberated by
grading activity or cultivation. Where established buffer vegetation is akead¥ in place,
substantially less buffer width is required to provide adequate protection. Woodard and Rock
(1991) found that, with established turf already in place, total phosphorus and TSS levels were
returned to background levels within about the first 25 feet of a vegetated buffer. Given
Minnetonka's relatively developed status, the city probably can successfully utilize buffer
standards that are less strict than in more actively developing communities. The buffer widths
proposed in the draft ordinance appear appropriate given the level of existing development and
the available scientific literature on buffers. We have provided more detailed discussion and
recommendations regarding buffer 'widths in the accompanying summary of buffer zone
research.
We haven't found evidence in the literature that non-native turf grass is any less effective in
removing nutrients and sediment than native grass. Current literature stresses that surface
roughness, slope gradient and density of standing vegetation and organic litter play key roles in
slowing and filtering water. Generally, if an existing buffer of non-native tuff grass is already in
place, we do not feel it is necessary to replace it with native vegetation. When lawns are used as
a buffer it does appear that mowing is a factor in buffer effectiveness. Pearce et al. (1997) found
that the effectiveness of increased buffer zone length as a sediment filter was enhanced by
increased vegetation height. Increased vegetation height would most likely produce larger plant
' Comments/Recommendations on Draft Mirmetonka Wetland Ordinance
0 February 12, 2001
Page 5
PEC Project No. 2000-013
stems and ultimately result in more leaf litter on the ground. If existing turf grass is left
mowed, it will provide a more effective buffer than if it 'is not.
There are a number of reasons that it may be desirable to replace an existing buffer of non-native
grasses to native vegetation. Typically, this is done because the area encompassed by the buffer
is thinly vegetated or is dominated by undesirable species. In most cases, native vegetation also
produces greater visual interest throughout the year and typically will have more habitat value
for wildlife. However, unless there is a specific reason to convert a non-native buffer to a native
one, we would generally recommend against conversion to avOid the increased risk of erosion.
Both the Plymouth and Eden Prairie wetland ordinances contain performance standard language
that defines when existing buffer vegetation must be re-planted. The City of Minnetonka may
wish to consider including this language in its ordinance as well.
The most common method of eliminating existing vegetation without tillage involves the
application of herbicides. Only those formulated for use near waterbodies should be used on
buffers (e.g. Rodeo, C-2,4-D and Accord). Herbicide can be applied any time of year while
vegetation is active. It is common to bum dead vegetation after herbicide application but this
may seldom be feasible in Minnetonka.
One problem with eliminating existing vegetation is that the buffer will not be as effective while
vegetation is being replaced. As a result, it is desirable to establish new vegetation as quickly as
possible. The most efficient method of establishing native vegetation is to plant containerized
plants about one week after herbicide is applied (one week is necessary to ensure that residual
herbicide does not damage the new plants). Native plant seed can also be raked into a buffer
where existing vegetation has been eliminated but it can take two or three years for prairie
species to become established. A combination of containerized plants and seeding is probably the
best option because the containerized plants will become established quickly and the seed will
eventually help fill in the buffer and ensure a dense stand of vegetation. Seeding of uplands
should be conducted between May 1 and June 15 or between October 15 and freeze up.
Generally, native grass seed that is over-seeded on a buffer or lawn that is currently growing will
not become established due to low light levels and competition fi'om existing plants. See the
"Native Wetland & Buffer Area Seeding Specifications" in Appendix A for information about
planting seed.
If buffers will be planted where there is exposed soil (especially on steeper slopes) we
recommend the use of fiber blankets. There are a variety of fiber blankets that are currently
available on the market that are useful for the establishment of vegetation. Most fiber blankets
are designed strictly to prevent erosion, however, there are new products on the market that have
vegetation planted directly into the blanket. The benefit of these products is that they can be
directly staked into the ground and no additional seeding or planting of containerized plants is
necessary. These products can also be contract grown to fit the vegetation to specific site
conditions. A local vendor of vegetation-impregnated blankets is Hild and Associates in River
Falls Wisconsin.
· Comments,rRecommendations on Draft Minnetonka Wetland Or ~dinmnce
.February 12, 2001
Page 6
PEG Project No. 2000-013
We recommend that trees be left in buffers as long as they are not shading out understory species
and allow for dense standing vegetation and leaf litter in the understory. Research on forested
buffers has demonstrated that they can be as effective as grass buffers (Osb°me & Kavacic
1993). Tree reots help add structure to soils as well as increase water filtration. Baffers under
trees that provide a significant mount of shade (e.g. silver maple and boxelder) may be
problematic in that they may shade out or out-compete understory species. Thinning these trees
may be beneficial in some cases. However their mots should not be disturbed due to possible
erosion. There aresome understory species that are adapted to dense forest conditions that could
be planted in areas of dense shade. Examples would be Virginia wild rye, cardinal flower,
obedient plant, Jack in the Pulpit, Virginia Creeper and Pennsylvania sedge.
Common and Glossy buckthorn (Rhamnus cathartica and Rhamnus frangula) are significant
problems in buffers because they produce dense shade and are believed to have an allelopathic
effect by which they inhibit growth of other plants. As a result, buckthorn commonly has no
plants growing beneath them, potentially leading to erosion. We recommend that buckthorn be
eliminated from existing buffers. Stumps should be cut and treated with a herbicide that can be
used near wetlands. Multiple treatments are typically necessary due to buckthorn's tendency to
aggressively re-sprout.
As stated in the accompanying "Summary of Wetland Buffer Zone Research & Buffer
Recommendations", phosphorus is typically the limiting nutrient in Minnesota waterbodies and
as a result, efforts to control nutrient loading such as buffers are typically oriented toward
phosphorus removal. Although buffers play an important role in reducing nutrient impacts, it is
also important to control nutrient loads at the source. Recent research by Barren and Jahnke
(1997) indicates that the application of phosphorus fertilizer to lawns with very high pre-
application fertility levels (estimated to be approximately 70% of suburban Twin Cities
metropolitan area homes) significantly increases the amount of phosphorus transported into the
storm water system by rainfall runoff. The University of Minnesota Soils Testing Laboratory in
fact recommends that phosphorus not be applied to these lawns. Based on this research, the City
of Minnetonka may wish to include in its wetland ordinance a prohibition on the application of
phosphorus-containing fertilizers. The city probably should not, however, prohibit the sale of
such fertilizers to avoid potential interstate commerce issues.
We note that the buffer widths in the draft ordinance may sometimes differ from those contained
in the Minnehaha Creek Watershed District's (MCWD's) ordinance. The City of Mirmetonka
may wish to request that projects regulated under the city ordinance be exempt from MCWD
buffer standards so as to avoid conflicts. Also, the city should consider what, if any, mitigation it
might require if encroachment into a buffer zone is unavoidable.
Ordinance Subdivision 9: Public Hearing Requirement
For administrative efficiency, the city may wish to consider some type of de minimis area so that
very minor wetland impacts do not require a public hearing. The WCA uses 10,000 square feet
as the minimum threshold for notice purposes. The city may wish to consider using either this
· "Comments/Recommendations on Draft Minnetonka Wetland Ordinance
. February 12, 2001
Page 7
PEC Project No. 2000-013
figure or the applicable WCA de minimis acreage (400 and 2,000 square feet in shorelands and
non-shorelands, respectively).
Issues and Questions Raised by the Planning Commission '(Pages 11-12 of the Staff Report)
Generally we concur with all the comments provided by city staff in response to the questions
and comments from the Planning Commission. We offer the following supplemental comments
on two of the issues that were brought up.
Retroactive application of buffer requirements to developed lots
We believe that applying buffer requirements to developed lots or even undeveloped lots of
record may adversely affect the reception that the amended ordinance receives fi:om the citizens
of Minnetonka. It also could create some liability. The Planning Commission also correctly
notes the difficulty of enforcing this type of requirement. On lots of record, landowner education
is probably a better option than requiring residents to give up the use of property they are
accustomed to utilizing.
Permanent versus temporary monumentation
We concur that, once installed, buffer monuments should be permanent. If they are only placed
temporarily, buffers edges will be subject to progressive encroachment. Also, buffer
requirements will not be adhered over the long term when if affected properties change hands.
We hope the foregoing comments are of assistance in the development of amendments to the
Minnetonka Wetland Ordinance. Please feel free to contact our office with any questions.
Best regards,
Peterson Environmental Consulting, Inc.
Daniel B. Shaw
Restoration Ecologist
Ronald P. Peterson
President
Prof. Wetland Scientist No. 1118
Enclosures
Literature Cited
Barten, J.M., Jahnke, E. (1997) Suburban Lawn Runoff Water Quality in the Twin Cities
Metropolitan Area, 1996 and 1997, Suburban Hennepin Regional Park District, pp. 16.
· ' Comments/Recommendations on Draft Minnetonka Wetland Ordinance
,February 12, 2001
Page 8
PEC Project No. 2000-013
Daniels, R.B. and J.W. Gilliam (1996) Sediment and chemical load reduction by grass and
riparian filters. Soil Sci. Soc. Amer. J. 60:246-251.
Pearce, R.A., Trlica, M.J., Leininger, W.C., Smith, J.L., Frasier, G.W. (1997) Efficiency of Grass
Buffer Strips and Vegetation Height on Sediment Filtration in Laboratory Rainfall Simulations.
Journal of Environmental Quality. 26:139-144.
Phillips, J.D. (1996) Wetland Buffers and Runoff Hydrology. In: Wetlands: environmental
gradients, boundaries, and buffers: proceeding of an international symposium, April .22-23,
1994/sponsored by the Wetlands Research Center, University of Waterloo, Ontario Canada. pp.
207-220.
Osborne, L.L, Kovacic, D.A. (1993) Riparian vegetated buffer strips in water-quality restoration
and stream management. Freshwater Biology 29, 243-258.
Schmitt, T.J., M.G. Doskey and K.D. Hoagland (1999) Filter strip performance and processes for
different vegetation, widths and contaminants. J. Envron. Qua128:1479-1489.
DRAFT
SUMMARY OF WETLAND BUFFER ZONE RESEARCH
& BUFFER RECOMMENDATIONS
PREPARED FOR ~ CITY OF 1VIINNETONKA
JANUARY 15, 2001
INTRODUCTION
The following narrative summarizes literature research done by Peterson Environmental
Consulting, Inc. (PEC) regarding the' effectiveness of wetland buffers and provides buffer
zone recommendations based on that infOrmation. This work was done to assist the City
of Minnetonka in developing the buffer zone component of a wetland ordinance currently
being contemplated by the city. The review and recommendations contained in this
report represents an update of earlier work done for the City of Plymouth during the
development of their wetland ordinance in 1994-95. As with Plymouth, it is our
understanding that the focus of any wetland buffer requirements adopted by the City of
Minnetonka will be based on the buffer performance in protecting down-gradient water
quality.
EFFECTS OF NUTRIENT LOADING AND SOURCES OF NUTRIENTS
Nutrient pollution is widely recognized as having an adverse effect upon water bodies
due to the resultant acceleration of eutrophication beyond rates found in nature.
Accelerated eutrophication in mm accelerates the rate with which open water areas
become vegetated, thus reducing interspersion between open water and vegetation. As
wetlands become overloaded with nutrients, the ability of such wetlands to remove
nutrients from inflowing water is reduced; thus, any downstream waterbodies become
more likely to receive inflowing nutrients that might otherwise be "stripped" by upstream
wetlands. Accelerated eutrophication of lakes increases the frequency and severity of
algae blooms resulting in reduced water quality and clarity with attendant odor problems
and aesthetic degradation. Eutrophication in lakes and deep water wetlands can also lead
to oxygen depletion that results in winter kills of fish species.
Phosphorus is typically the limiting nutrient in Minnesota waterbodies (Smith and
Shapiro, 1981). Consequently, measures for controlling nutrient loading are typically
oriented toward phosphorus removal. However, this does not mean that other nutrients
are not being treated; generally the measures that are implemented to remove phosphorus
are also effective at reducing the loading of other nutrients.
The most frequently reported phosphorus value is total phosphorus (TP) which consists
of dissolved inorganic and organic phosphoms compounds and phosphorus adsorbed to
soil particles and in organic matter. Sediment loads are typically expressed in terms of
total suspended solids (TSS) which are generally represented as g/kg or g/l. Phosphorus
binds to fine particles that are .suspended in runoff and can ultimately be washed into
wetlands and downstream waterbodies. Because phosphorus binds to soil particles,
sediment loads can also be a measure of water-borne nutrients. In addition to carrying
nutrients, sediment deposits can ultimately impair the water quality treatment function of
wetlands through the burial of wetland vegetation. Sediment can also seal pond beds,
resulting in decreased infiltration. Consequently, sediment trapping is also an important
function of buffer zones around wetlands.
Phosphorus generation varies by land use. Land uses with high proportions of
impervious surface typically generate the highest loads of water-borne phosphorus.
Phosphorous laden dust lands on impervious surfaces where it has no soil to adhere to
and vegetation to be taken up by. Phosphorus accumulates over time until a storm event
generates sufficient runoff to "flush" the accumulated phosphorus downslope and/or
downstream. Consequently, phosphorus generation from impervious surfaces tends to
occur in "slugs'' with large volumes of phosphorus being discharged over relatively short
periods of time.
Conversely, land uses with high proportions of pervious surface, particularly if densely
vegetated, typically have lower phosphorus generation rates due to lower mnoff
volumes/rates and the capacity of the soil and plant life for binding phosphorus. A study
of phosphorus generation in Maine indicated that a low density residential subdivision
(less than 2 units per acre) generated approximately 5 to 10 times the phosphorus that is
exported from forested land (Dennis, 1985). Phosphorus enters the atmosphere due to
erosion (both water and wind related), deposition and re-suspension of road dust (to
which phosphorus adheres), release by live plants, release through the decomposition of
dead plants, and artificial release of phosphorus by humans in the form of fertilizers.
In a four-year study in Wisconsin, Bannerman (1992) found the following sources of
phosphorus in residential/institutional, commercial and industrial areas:
Residential/Institutional Areas:
lawns account for 34.4% of P
driveways account for 20.2% of P
streets account for 44.4% of P
roofs account for 0.7% of P
Commercial Areas:
streets account for 72.3% of P
parking lots account for 18.9% of P
roofs account for 5.9% of P
2
sidewalks account for 3.0% of P
Indusu'ial Areas:
lawns account for 19.4% of P
streets account for 29.9% of P
parking lots account for 44.2% of P
roofs account for 6.5% of P
It is clear from Bannerman's (1992) results that impervious surfaces generate the most
phosphorus even with residential land uses, which typically have the lowest proportion of
impervious surface among the various types of development. However, residential lawns
still represent an important source of phosphorus. In residential areas, lawns account
for 66% of the total land use and generate runoff with the highest concentrations of
phosphorus (due largely to the relatively small volume of runoff carrying the phosphorus)
(Bannerman, 1992). Recent research by Hennepin Parks on the fertility of 181 lawns in
Maple Grove, Plymouth, Eden Prairie and Minnetonka, Minnesota indicated that 70
percent of the lawns studied had high levels of fertility. Lawn nmoff data collected in
1996 and 1997 indicated that the application of phosphorus fertilizer to lawns that already
have high phosphorus levels significantly increases the amount of phosphoms transported
into the storm water system by rainfall runoff (Barten & Jahnke 1997).
Measures to remove phosphorus from stormwater vary depending on whether discharges
are coming from impervious versus pervious surfaces. Runoff from roadways and
parking lots is typically channeled into the storm sewer system and treatment must be
done through detention of surface water to allow settlement of phosphorus-bearing
sediment. Reduction of initial phosphorus generation fi.om such surfaces would be done
through the increased frequency of street cleaning activities. Runoff from pervious
surfaces typically runs downslope overland, rather than via storm sewers. Thus,
treatment measures to remove phosphorus from such runoff must be "non-point".
Vegetated upland buffers around wetlands represent such a measure. Buffers slow
runoff, thus increasing percolation, adsorption of phosphorus to soil particles and the
uptake of phosphorus by plants. Reduction of initial phosphorus generation from
pervious surfaces must also be done by non-point methods such as erosion control
measures and fertilizer restrictions.
It is desirable to minimize phosphorus loads to wetlands both to avoid accelerating the
eutrophication process within the wetland and also to protect the ability of wetlands to
protect downstream waterbodies. Treatment of runoff from impervious surfaces is best
dealt with through proper stormwater engineering and management practices; thus, we
have not discussed such measures for potential inclusion in a wetland ordinance.
However, a wetland ordinance is an appropriate vehicle for adopting measures to protect
wetlands fi.om water-borne nutrients carried by runoff from pervious surfaces. Vegetated
buffer zones are the most widely recognized measure for accomplishing this objective.
EFFECTIVENESS OF VEGETATED BUFFER ZONES IN REDUCING
PHOSPHORUS AND TSS LOADS TO WETLANDS
In 1994-95, PEC carried out an extensive literature review regarding wetland buffer
performance for the City of Plymouth. This review was done to provide a sound
scientific basis for the adoption of wetland buffer provisions as a component of a city
wetland ordinance. The focus of this review was to identify and analyze scientific
research papers that quantitatively analyzed the performance of vegetated buffer strips in
removing phosphorus and sediment from runoff emanating from developing residential
areas. The results of this review were heavily scrutinized and a number of additional
research papers were brought to our addition by consultants for the Plymouth Developers
Council. Ultimately, only one study was found to be truly "on point" and represented the
primary basis for buffer recommendations that were made to the City of Plymouth at that
time.
Woodard and Rock (1991)
Woodard and Rock (1991) analyzed the phosphorus and sediment removal efficiencies of
vegetated upland buffers in developing residential areas in Maine. A full copy of this
paper is attached to this report as Appendix A. This research was found the most useful
for developing buffer recommendations because it entailed:
nutrient and sediment removal data collected in sim on developed and developing
residential sites, as opposed to simulations conducted under laboratory conditions,
comparison of treatment sites to undeveloped control sites,
comparison of buffer performance on steep versus gentle slopes,
· comparison of buffer performance down-gradient from established turf versus freshly
graded land, and
· analysis of progressive removal efficiency over the entire width of the buffer.
The analysis done by Woodard and Rock (1991) allows for the identification of the points
of diminishing benefit with regard to buffer width under a variety of conditions. While
this study was found to be the most useful, it has a number of inherent weaknesses. The
study lumps monitoring data from an unspecified number of precipitation events without
weighting or giving consideration to other event parameters such as storm
intensity/duration, antecedent climatic conditions and the intervals between precipitation
events. The variation in pollutant concentrations in runoff.was not provided for either
treatment sites or control sites. The authors of the study expressly stated that actual
pollutant concentrations varied considerably between storms and cited some examples.
This approach would tend to overestimate pollutant removal efficiency during significant
storm events following extended dry periods while underestimating efficiency during less
intense and more evenly timed storm events. However, for purposes of evaluating overall
buffer performance, evaluating average conditions seems appropriate.
Also, Woodard and Rock (1991) do not spell out how storm events were selected for
sampling. It is most likely that small storms with negligible runoff may not have been
sampled. By excluding such storms, the authors actually reduce the average pollutant
removal efficiency ascribed to a buffer of a given width. This suggests that Woodard and
Rock (1991) may be akin to a "worst case" analysis and that buffer widths based on their
results might actually be somewhat conservative.
Salient results of the Woodard and Rock (1991) study are as follows:
· Buffer strips on gentle sloping sites were effective at removing phosphorus and
total suspended solids (TSS) for all storms sampled.
A fifty-foot buffer strip downslope of a new condominium development and a
two-story house reduced the phosphorus concentration by approximately 60
percent, bringing it to within background levels. Background levels were
determined by monitoring a control site without any nearby development.
A buffer zone downsiope of a new housing development built on 12 percent
slopes reduced phosphorus concentration by 88 percent in the first fifty feet and
94 percent in the first 75 feet while the phosphorus concentration downslope of
the existing home declined by 50 percent after 75 feet, and by 65 percent within
100 feet. The lower removal efficiency at the existing home was attributed to the
fact that the phosphorus removed comprised a lower percentage of the incoming
phosphorus load because that load was so small.
In all cases a 50-foot buffer was effective in reducing phosphorus and TSS to
approximately background levels.
· In all cases a 75-foot buffer was effective in reducing TSS to background levels.
As a result of their study, Woodard and Rock also concluded that a 75-foot
buffer zone was adequate to reduce both inflowing phosphorus and total
suspended solids concentrations to background levels under essentially "worst
case" conditions (i.e. 12 percent slopes, freshly graded land and no erosion
control).
If erosion control had been in place and effective at the construction sites
studied, less buffer strip width than described above would have been needed to
adequately protect water quality.
Since our 1994-95 literature review, much additional research has been performed on
buffer effectiveness. In updating our prior review, we have focused on identifying and
analyzing applicable newer research to determine whether it might suggest a need for
changes to the earlier recommendations based on Woodard and Rock (1991). Only
quantitative research was sought. We did not consider "gray" literature that repozted only
anecdotal information, summarized prior quantitative research or provided unsupported
buffer recommendations. Appendix .B provides a listing of papers we reviewed and
found to be inapplicable. Newer studies that were found to be relevant are supplied in
their entirety in Appendix C and are summarized below. It should be noted, however,
that the most relevant newer studies were oriented toward agricultural land uses and did
not appear to be as well designed as Woodard and Rock (1991). These studies are as
follows:
Recent Buffer Studies
Schmitt, Dosskey and Hoagland (1999)
Schmitt, Dosskey and H°agland (1999) conducted a study comparing the effectiveness of
different buffer widths on four sample plots with established vegetation of different ages
and compositions. The plots consisted of; (1) a 2-year old switchgrass and tall fescue
plot, (2) a 2-year old grass-shrub-tree plot consisting of bush honeysuckle, golden
currant, eastern cottonwood and silver maple, (3) a contour sorghum plot planted with
grain sorghum and (4) a 25-year old grass plot with an unspecified plant composition.
Each of the four plots was divided into 7.5 and 15 meter (24.6 and 49.2 feet),
respectively. The researcher's utilized a simulated rainfall representing a 1-yr return
frequency. Water stored in a polyethylene tank was applied to each plot via an overhead
sprinkler system. After nmning through the buffers, runoff was collected at the bottom
of each plot in 2700-1iter steel tank.
The researchers found that doubling the filter strip width from 7.5 to 15 meters (24.6 to
49.2 feet) did not significantly increase the removal of total suspended solids (TSS). TSS
decreased an average of 77 percent for the 7.5-meter strip and 83 percent for the 15-meter
strip, regardless of the vegetation compositions tested. These removal rates were
comparable to the TSS removal rates observed by Woodard and Rock (1991) for
approximately the same buffer widths on a steep slope with an established lawn.
(Woodard and Rock, 1991 observed higher TSS removal rates downgradient of disturbed
soils, apparently due to a higher TSS concentration in runoff entering the buffer).
In the 2-year old grass and grass-shrub-tree plots, total phosphorus decreased 57 and 72
percent in the 7.5- and 15-meter strips, respectively. In the 25-year-old grass plot total
phosphorus decreased 71- and 79 percent in the 7.5- and 15-meter strips, 'respectively. In
the contour sorghum plot, total phosphorus decreased 48 and 51 percent in the 7.5- and
15-meter buffer strips, respectively. It seems apparent from these result that higher total
6
phosphorus removal rates were achieved with longer-established grouncleovers having
progressively greater amounts of thatch.
Schmitt, Dosskey and Hoagland (1999) demonstrated that a variety of vegetation types
could produce similar sediment and nutrient pollutant removal rates. The most effective
buffer in the study was the 25-year old grass plot which would be similar to a well-
established, mowed grass buffer strip around an existing wetland in Minnetonka. The
TSS and TP removal rates observed in this study were very similar to those observed in
Woodard and Rock (1991). Both studies suggested that about half to two-thirds of the
phosphorus entering the grassed buffers was removed within about the first 25 feet and
that about three-fourths was removed by about 50 feet. Schmitt, Dosskey and Hoagland
(1999) did not include an undisturbed control site in their study, so it is not possible to
determine what buffer width was necessary to return sediment and nutrient pollutant
concentrations to background conditions. Also, by simulating rainfall from more
frequent, low intensity storms, this study did not. assess the buffer performance across a
variety of storm intensities.
Patty, Real & Gril (1996)
In another study, Patty, Real & Gril (1996) compared the effectiveness of buffer strips of
6, 12 and 18 meters (19.68, 39.36 and 59.04 feet) at three individual agricultural sites.
The three sites differed as to; (1) the type of crop that water flowed through before
entering the buffers, (2) the amount of precipitation falling during the study period, (3)
soil type, (4) slope and (5) age of buffer vegetation. Because the sites differed in so many
ways, it is difficult to ascribe differences in relative buffer performance to specific
variables. Also, no control site was included in the study, so it is impossible to compare
any of the treatment sites to undisturbed, fully vegetated land.
At one site rain water flowed through corn planted parallel to the slope before entering
the buffers. This site had a total rainfall for the year of 25.59 inches and silt loam soil
with 2 percent organic matter and a mean slope of 7 percent, The second site had a total
rainfall of 36.22 inches that flowed through corn planted parallel and perpendicular to the
slope, there was silt loam soil with 7 percent organic matter and a 10 percent slope. The
third site had a total rainfall of 27.56 inches that flowed through a plot of winter wheat,
there was a silt loam soil w/th 3 percent organic matter and a 15 percent slope. Buffer
strips for all sites were planted to of rye-grass, sown perpendicularly to the slope. Runoff
was collected in a tank after it had flowed through each buffer. The rye grass was
unmowed, and was 3.5 years old in the first site, 2.5 in the second and 1.5 in the third.
It was found that 87, 98.9 and 91 percent of the runoff-borne sediment was trapped in the
6 meter buffer strips on the first, second and third sites, respectively. Between 97 and
100 percent of the runoff-borne sediment was trapped in the 12- and 18-meter buffer
strips, on all three sites. Although treatment conditions varied significantly between the
three sites, they all had high uptakes of sediment (87-98.9%) within the first 6 meters
(19.68 feet) of buffer. However, because no control site was analyzed, it is not possible
7
to derive points of diminishing benefit for the buffer widths analyzed. Patty, Real & Gril
(1996) did not analyze changes in total phosphorus concentrations across the buffers they
studied.
Daniels and Gilliam (1996)
Daniels and Gilllam (1996) determined the mount of nutrients and sediment removed by
buffer strips that received nmoff from cultivated fields after natural rainfall. The buffer
areas consisted, primarily of unmowed fescue (Festuca arundinacea) but also consisted of
combinations of weeds, shrubs, trees and unspecified groundcover. Runoff was
collected using a V-shaped passive collector, which directed flow into a buried bottle that
was sealed with a floating plastic ball. Collectors were located at field edges and at
various locations in vegetated buffers. They found that at around six or seven meters
(19.68 to 22.96 feet) into grass buffers, 60 to 70 percent of incoming total phosphorus
was removed. Results were poorer in buffers listed as a combination of grass and
riparian area, with 30 to 45 percent of total phosphorus removed within the first 7 meters
of the buffer.
These results also appear consistent with Woodard and Rock (1991), in that over half of
the runoff-borne total phosphorus is removed within the first 6 to 7 meters of the
vegetated buffers. The low phosphorus removal of 3045 percent by the grass-riparian
buffer is inconsistent with other study results and probably results from the buffer having
insufficient ground cover. Again, as with other recent studies, Daniels and Gilliam
(1996) did not compare their treatment sites.with undisturbed, natural conditions. Thus,
it is not possible to derive points of diminishing benefit for the buffer widths analyzed.
None of the newer studies in our updated literature review on buffer performance
contradicted the conclusions we reached in our 1994-95 review, nor did these studies
suggest any refinements that might be made. Accordingly, the conclusions we drew
earlier based on Woodard and Rock (1991) appear to remain valid.
BUFFER ZONE RECOMMENDATIONS
Wetlands vary in their susceptibility to damage from nutrient loading. For purposes of
developing buffer zone recommendations, we have assumed that substantially degraded
wetlands are less susceptible to additional nutrient-related damage than relatively
undisturbed basins. From a public benefit standpoint, we believe that it is most
appropriate to utilize degraded wetlands to remove phosphorus and sediment from runoff
rather than pursue extraordinary measures to protect them from it. Conversely, relatively
undisturbed wetlands warrant a higher degree of protection from nutrient loading so as to
preserve the characteristics that make them of high or exceptional quality.
In determining the quality of wetlands for purposes of setting required buffer widths, we
recommend that the floristic diversity and ecological integrity of each wetland be the
primary determinant. This is the approach taken by the Cities of Chanhassen and Eden
Pr~drle. The methodology we used ~u P~ymouth encomp~sed the ~ul~ su~e of we~nd
functions and values. We feel this approach may have resulted in some wetlands being
assigned a higher quality classification due to their flood storage or water quality value;
thus, some wetlands may be receiving more protection than their ecological status might
warrant.
The four wetland classifications discussed in the 1999 Minnetonka Water Resources
Management Plan (i. e. Preserve, Manage 1, Manage 2 and Utilize) appear to fall
somewhere in between approaches taken by Plymouth versus Eden Prairie and
Chanhassen. Preserve wetlands include: (1) "special resources", (2) wetlands having high
management potential due to their intrinsic non-stormwater functions and local values
(fish and wildlife habitat, floral diversity, groundwater recharge or aesthetics/recreation)
and (3) wetlands found to be highly susceptible to stormwater impacts based on guidance
from the Minnesota Stormwater Advisory Group (1997). Manage 1, Manage 2 and
Utilize wetlands do not meet any of the criteria for Preserve wetlands and have moderate,
slight and least susceptibility to stormwater impacts, respectively. We have summarized
the management objectives for each of these wetland classifications and our associated
buffer strip recommendations below. It should be noted that all buffer recommendations
assume that sound erosion control measures will be in place and rigorously maintained
until turf is well established upgradient from each wetland.
Preserve Wetlands
As the designation suggests, Preserve wetlands are to be preserved with all adverse
impacts to be avoided if possible. The hydrology of and nutrient load to these wetlands is
to remain unchanged. Under "worst case" conditions (i.e. steep slopes, active
construction and no erosion control), the point of diminishing benefits for removal of
total phosphoms and total suspended solids would be about 50 and 75 feet, respectively.
If sound erosion control measures are in place and rigorously maintained until turf is
well-established upgradient, the 50-foot buffer width called for in the draft Minnetonka
wetland ordinance should be adequate to serve both functions. To ensure that buffers
around Preserve wetlands are not compromised where steep slopes are present, the City
may wish to consider requiring dual silt fences in such locations~. In such places, one
row of silt fence would be placed at the wetland boundary and the other at the upper limit
of the buffer.
~ Dual silt fences with intensive maintenance have been found suitable for providing the special
erosion/sedimentation control measures needed to allow the use of narrower buffers. If silt fences with an
AOS filter size of 70 microns are used and are properly maintained, they are capable of removing
approximately 90 percent of the sediment-borne phosphorus in water passing through them (Lou Flynn,
MPCA, pers. comm.) Properly maintained dual silt fences should increase this removal rate to nearly 99
percent. It should be noted, however, these very high efficiencies are easily (and frequently) lost when silt
fences are undercut, overtopped, ripped or pushed over by sediment. Frequent maintenance is critical.
Dual silt fences should be considered properly maintained if inspected and repaired/maintained as needed
following each significant rain event (more than 0.5 inch) until the project site is fully re-vegetated.
Manage 1 Wetlands
Adverse impacts to Manage 1 wetlands are to be minimized, changes to their hydrology
are to be controlled, incoming sediment is to be removed and water "pre-treated" to
remove nutrient pollutants. For relatively flat sites and sites with established tuff, a 25-
foot buffer appears adequate for removal of suspended solids and total phosphorus.
However, on steep slopes without erosion control, at least 50 feet is necessary to remm
total suspended phosphorus levels to roughly background levels (see the lower right-hand
graph in Figure 2 from Woodard and Rock (1991)). With proper erosion control, the 25
foot buffer width proposed by the City of Mianetonka appears adequate. Again, as with
Preserve wetlands, the City may wish to consider dual silt fences where steep slopes exist
around Manage 1 wetlands to ensure that the buffer is not compromised.
Manage 2 Wetlands
Manage 2 wetlands are to be managed in a fashion similar to Manage 1 wetlands, but less
emphasis is placed on pre-treatment of incoming water for nutrient removal.
Accordingly, we recommend a buffer width that will remove a reasonable percentage of
the incoming suspended solids. The City has proposed a buffer width of 16.5 feet (5
meters) around Manage 2 wetlands. Patty, Real & Gril (1996) found very good removal
percentages for runoff-borne sediment in 6 meter buffer strips (i.e. 87 to 98.9 percent
removal) on slopes up to 15 percent. While Woodard and Rock (1991) did not analyze
buffer widths under 25 feet, their data suggest that, except for steep slopes on active
construction sites, concentrations of total suspended solids were approaching background
levels within that initial 25 feet. While the 16.5-foot width proposed by the city will not
provide quite the level of sediment removal afforded by a 25 foot buffer, it is probably
adequate for Manage 2 wetlands given their intended protection level.
Utilize Wetlands
Utilize wetlands are to be used for flood storage and pre-treatment of water prior to its
discharge to other wetlands or waterbodies. Given the degraded nature of these wetlands
and their intended use, little or no buffering is warranted. We concur with the language
in the draft ordinance, which provides no buffers for Utilize wetlands.
BUFFER AVERAGING
The buffer widths cited above are very similar to the alternative buffer standards provided
in the City of Plymouth's wetland ordinance. Use of the alternative standards required
the application of extraordinary measures to control erosion and sedimentation for two
years after construction. The dual silt fences mentioned above would represent one such
form of extraordinary management measure. In order to afford more flexibility in site
design, Plymouth utilizes average, minimum and maximum buffer widths in its
10
0rdinance2. We believe this is a sound approach in that it gives the designer some
flexibility to work around constraints and sensitive resources on any given site. Usually
it prevents the creation of regulatory taking situations in constrained areas (e.g. on
peninsulas). The City of Mirmetonka may wish to consider the use of buffer averaging as
an element of its ordinance.
LITERATURE CITED
Literature Cited
Bannerman, R.T., Dodds, R., Owens, D. and P. Hughes. 1992. Sources of Pollutants in
Wisconsin Stormwater. Wisconsin Department of Natural Resources. 25 pp.
Barten, J.M., Jahnke, E. 1997. Suburban lawn runoff water quality in the twin cities
metropolitan area, 1996 and 1997. Suburban Hennepin Regional Park District. 16 pp.
Daniels, R.B. and J.W. Gilliam (1996) Sediment and chemical load reduction by grass
and riparian filters. Soil Sci. Soc. Amer. J. 60:246-251.
Dennis, J. 1985. Phosphorus Export From a Low Density Residential Watershed and an
Adjacent Forested Watershed. In Lake Proceedings of 5th Annual Conference, North
Amer. Lake Mgt. Soc., Lake Geneva Wisconsin, pp. 401-407.
Dillaha, T.A., R.B. Reneau, S. Mostaghimi, and D. Lee. 1989. Vegetative filter strips for
agricultural nonpoint source pollution control. Trans. ASAE 32:513-519. ·
Doyle, R.C., G.C. Stanton and D.C. Wolf. 1977. Effectiveness of Forest and Grass Buffer
Strips in Improving the Water Quality of Manure Polluted Runoff. American Society of
Agricultural Engineers, Paper NO. 77-2501.
Interagency Task Force on Wetland Delineation. 1989. Federal Manual for Identifying
and Delineating Jurisdictional Wetlands. 76 pp.
Patty, L., B. Real and J.J. Gril (1997) The use of grassed buffer strips to remove
pesticides, nitrate and soluble phosphorus compounds from runoff water. Pesticide Sci.
49:243-251.
City of Plymouth Alternative Buffer Standards with Extraordinary Management Measures
Wetland Quality
Exceptional High Medium Low
Avg. Buffer Width 30 ft 25 ft 15 ft 10 ft
Min. Buffer Width 25 ft 20 ft 10 ft 5 ft
Max. Buffer Width 50 ft 30 ft 20 ft 15 ft
11
Sartor, J.D. and G.B. Boyd. 1972. Water Pollution Aspects of Street Surface
Contaminants. U.S. Environmental Protection Agency Report No. EPA-R2-72-081.
Schmitt, T.J., M.G. Doskey and K.D. Hoagland (1999) Filter strip performance and
processes for different vegetation, widths, and contaminants. J. Environ. Qual. 28:1479-
1489.
Smith, V.H. and J. Shapiro. 1981. Chlorophyll-Phosphorus Relations in Individual Lakes;
Their Importance to Lake Restoration Strategies. Env. Sci. and Technology. 15:444-451.
Westerman, P.W., M.R. Overcash, and S.C. Bingham. 1983. Reducing Runoff Pollution
Using Vegetated Borderland for Manure Application Sites. U.S. Environmental
Protection Agency Report No. EPA-600/S2-83-022.
Woodard, S.E. and C.A. Rock. 1991. The Role of Natural Buffer Strips in Controlling
Phosphorus and Sediment Runoff. In Proceedings of the 64th Annual Conference and
Exposition of the Water Pollution Control Federation, Report No. AC91-044-004.
12
vegetation to increase habitat diversity. A schematic
illustrating these design criteria is presented in Figure 4.3.
4.2.3.2 Buffer Strip Classification
A buffer of undisturbed vegetation around a wetland can
provide a variety of benefits (Figure 4,4). The buffer can
consist of trees, shrubs, grasses, wildflowers, or a
combination of plant forms. Buffers reduce the impacts of
surrounding land uses on wetland functions by stabilizing soil
to prevent erosion and filtering solids, nutrients, and other
harmful substances. Buffers also provide"essential habitat for
feeding, roosting, breeding and rearing of young birds and
animals; and cover for safety, movement and thermal
protection for many species of birds and animals. Buffers
can reduce problems related to human activities by blocking
noise and glare from lights, and reducing disturbance. Even
a 10-20 foot buffer of tall vegetation can provide some water
filtering benefits, but wider buffers will provide additional
water quality and habitat benefits.
Buffers can be planned to tie important upland habitats to
wetlands, or connect wetlands and other waters. Since many
animal species require both wetland and upland habitats as
part of their life cycles, and also require opportunities to
move to escape predators or find food and cover, buffers
should be planned to maximize these connections. Buffers
will be most effective if the landowners around a wetland
cooperate to make a continuous buffer, and connect
desirable wetland and upland habitats.
Landowners should avoid cutting vegetation, dumping grass
clippings or other debris, and trampling in buffer strip areas.
If a path is desired through the buffer, it should be mown
only as wide as necessary for walking, and gently
meandered so that it does not encourage erosion or carry
sediments and nutrients from surrounding areas to the
wetland.
];t is recommended that the City adopt buffer strip width
standards for each wetland based on the function and values
assessment for that wetland. The recommended buffer strip
standards and management goals for wetlands in Wayzata
are presented in Table 4.3.
Q'ty of Wayzata
4-13
Storm Water Management Plan IJp~ate
THE ROLE OF NATURAL. BUFFER STRIPS IN CONTROLLING PHOSPHORUS
AND :~iMP. J4T RUNOFF
Graduate R~ ~t
Depamnent of Civil Engineering
'Purdue University, lafayette, IN-47906
Chet A. Rock
Professor and Chair
Department of Civil Engineering
University of Maine, Orono, ME
While most point sources o! pollutants have been controlled, no~=oint sources
continue to be s major problem. Even lov~ density residential subc~visions (less'th~n 2
units/acre), which are the most common development in Maine watersheds, can have a
significant
phosphorus export from these developments ~n companson to ~orestec~
Since it is dh'ficult to collect and concentrate diffuse and scattered sources of
pollutants, effective controls must also be 'nonpoint'. The use 6f 'buffer strips is on.e
'nonpoint' control that is'widely practiced in Maine, yet design remains an intuitive pm~
and effectiveness has dot been quanl~e~ As more development pressure is placed upon
our relatively pristine lakes, buffer strips will be increasingly relied upon to protect water
quality. Given the irnpo~ls~e of buffer saips, information on the co. rrect sizing is needed.
The objectives of this project, were threefold:
(1) Given that the phosphorus load ,~r~ be increased 5 to 10 fold above baclccjmund,
determine how effective a buffer strip is in minimizing this impact;
(2) Evaluate the ph~osphorus retention as a funclton of the slope and length of buffer strips,
and
(3) Using suspended solids as a measurement, quant~ the reduction in sediment.
MethodoloeY
This field study was c=nducted on six specific sites, selected for uniformity of
vegetation and soil type, with slope being he prime variable. In add'trion, a control site
without any nearby development was monitored The sites =all had vegetation typical of
Maine iakeshom (mixed growth, uneven age stand, predomina~Uy .h~..dwood, mo.dera~.,
ground cover of shrubs, ferns, etc.). In con'junction with the similar'vegetation, a common
type, glacial till, was also selected to give the broadest application to the data.
The slopes considered were classified as either gentle- or steep-sloped. The sites
were all at least 150 feet in length so that the influence o! increasing the length of the buffer
a'trlps ~uld be tested. Width w~ arbltm,*i ~ ~ 50 leal .~.e dram re~ved mlmv~ted.lnput~
of suspended solids anl~~Slf~J~~_ .~ ~sion, e cor~..m~nium
.'nobile home park. At each samp~ng site, a mimmum of 3S uniquety oesignect couecuon.
cups anti sleeves were pin, ecl into the ground ~gure 1). The sarnpnng grids con.~stecl of
seven to eight rows with five cups in each row. The tirst row of collection cups was placed at
the beginning of the buffer strip, where runoff t~rst entered the undisturbed, vegetated area_
This row of cups provided an indication of the P axld T,5~ concentrations in each pa~cular
devaloprnenrs runoff. The remaining rows of cui~ extended back into the buffer s'~fp. The
cups were set a~; a spacing of appmx[mamly lZ feet apaxt, reAulting in 4&-foot rows, with one
row every 25 feet. By putting five cups in each row, expeflme~ error was reduced by taking
the geometric mean of values obtained in e~ch row.
One of the goats of this study was to examine the influence of slope, in order to allow
better design of buffer strips in the ad=re. Current state orcEnances do not take slope into
corlsidetation, Th~s, ~s~~ re~_ide _filial ~ ,.. i. S fee, no matter
how steep the prope are mom easily
transpo, ned over steep slopes, neglecting slope...m~ be inappropriate. To .study the slope
factor, it was necessary t~ keep vegeta~on and sod type as constant as poss~me, so as to limit
the influence of these variables, it was also advantageous for the slope t6 ~e as uniform as
possible, with no outstaying high or low spots.
In addition to determining the effect of slope, the influence of seasonal crflferences was
also targeted for examination. Because Maine has seasonally differing storms that may
imp~[ct receiving waters, the sites were monitored from the disappearance of snow cover
(April) until the first major snow (November).
Although six sites were sampled during this projecL'the scope of this paper is 5mited to
four sites. The four sites provide a comparigon of two slopes, construction activity, and
influence of ground cover. R.esidential.builcEng~ot[ was undetway~.three..ef the
sites (A, B, E), while dwellings were already in.place at the other site (F). The control site (G~' -'
was located in the University Experimental Forest. There, only natural background sources
of nutrients are present and the slope is gentle and evee (5.7 %).
Sites A and El were the gently sloping.s~tes (3.3 %~ 2.3 %, respectively) with mixed
stands of hardwoods and pines. Condominium constrdcaon was underway at Site A when
the sampling cups were in=ri,ed in the fall The sample sites were left undistut'oed until the
following April when the first storm was sampled. During.the summer, the l~m was seeded
and .re .rtilized. This provided an excellent opportunity to study the effect of constru~c~-'and
landscaping on phosphorus and susp&nded solids levels. Site B provided a similar situa~on.
Construction of a two-story house was underway during sample cup installation, and the
lawn was seeded during the summer.
Steep sites E and F (both 12 %) are located on the shores of Kezar Pond, a
~utriept sensitive lake in Winthrop, Maine. These sites am particularly interesting because
they received special--attention from the Maine Depaxtment of Environmental Protection'
(DEP). Before constn~clJon, it was con. c. luded by the DEP that a ~ff_..~,er, s~1~.~,~ le .a.a.a.a~
~ema[n in place due to the sertsitive nature of the pond. Both sites were located in the.
same su .... d of hardwoods and sottwoods. At the t/me et
sample cup installation, a house on Site E was under construc~.'on. Construction continued
throughout the monitoring peflod and the lawn was not yet seeded at the end of s~npling.
Site F', on the other hand, was a two-year old house with an established lawn.
0.6 in ~
{3round surfa~;e
. -6in ·
SAMPLE
COLLECTION
CUP
(Removable)
1.85 in
.~-Collar
6in
0.25 in
PLASTIC SLEEVE
(Permanent)
Figure 1. Desert of sample c=ilection cup and p~. rmanent in-ground border.
' ' were m~, ~pper~ ~mn, ~a, ~ re~ ~ am . _
~ll~on, the ~ps ~ to m~ve
~e deb~, su~ ~ ~ves or ~gs. Ine vo~me o~ ~u~g ~m~
3
analyzed for total phosphorus (sulfur-nitric acid d/gestJan method) and total suspended
,dids in acmrdance w th 3 daU UeCh0ds (American Pubic HeaJth Association 1989).
I'he da~a were used to calcutate the phosphorus and suspended solids inputs to the buffer
strip and the subsequent changes every twenty-five..f, eet along the length of the buffer strip.
The data were a~aly'zed with respect to buffer strip length, 'siope, construc~on activity, and
· b'tO, ~'~ ergot.. .
Results
The d~n are depicted in graphical form, showing average row means for ail storms ~t
each site (F~um 2). Sites A and B, the gently sloping sites, are shown together as am Sites
E and F, the steeper sites. Included in each gra~oh is the average of all concentz~ons
sampled at the control site, ShOWa 'with a band of plus or minus one steaded deviation. Site
A was Ioca,ted directly downslope of a condominium development, which was under
c~nstruction throughout the saznp~ng period. Site B was located ~rectJy downs[ope of a two-
story house, which was also under construction.
Buffer strips on gentle sloping sites were effective a~ removing .P for all storms
sampled. Fifty_ t_eat of buffer strip reduced the P concenlzation by _ao~_a~ely 60 perc~:
bringing it to within the ~ltr0'C~and (1.5'/~.6~mg/L). The' remaining 100 feet of buffe~:~ri{3
reduced the P conce__ntmlJo? by aaother 10 perc.~, nL
A close look at F~gure 2 reve~_ls that the eff'~ency of ~ buffer strip, declines .a~ t.he
?_.noff travels farther onto the strip., Un fact, the TSS concentration actuaJly mcrea.s, ed in the
~ three rows of monitorihg cup~'~ Both sites (A and B) had a visible b. ct¢ of underbrush in
.,~is region to anchor the soil, whiEi may explain the sudden ~ irt this situate, the buffet'.
strip itself caz~contz~ute indigenous P and TS$ to the runoff.~l, the initial 25 ~et reduced
the TSS level by..~50[percent and the bad<ground range (127'J:62 rog/L) was reached within
75 feet for Site A~ Because of the loose, erodible nature of the soil at Site
concentrations never dropped to average control vaJu~
The steeper sites were located in a new housing development with Site F located two
house lots (appmxirrately 300 feet) away from Site E. The house on Site F, however, was
two years old and i~rf a well e. sta~shed lawn. The difference in activity was sharply
reflected in the concentr'aZ~ons entering the buffer strips. The removals ~t Site E were t.he
most..,.%ubstantiai of any site, largely due to the thick, porous ma, t of organic duff covering tt~e
soil. ~:]~e P_.,concen_~_~on ~ reduced by 88. percent in .the first f[fty_fee~._ _a~d_..94_.p. erce~.n~e~
first 75 feet~ In contrast to the ra~oid decline ? Site E, the P concentration ~t Site t' aec. J~_nea~
anly-'sligh~. After 75 teat, the concentration was reduced by about 50 pement and 65
percent within 100 feet. The co..mpamtively iow removal.at .Sim F~wa~..dF.e.p.n.'marily.to..th_e- f_a~.
tl~t the entering P was ve.ry Iow and in f,3ct was dose to the bad<ground, level (F'~cjure 2).
r'-The buffer strip at Site E~was even more effective st TSS removaJ, reducing the TSS
by 9713'A_rcent in.the Jirst_75Jeet_/.The additional, lOB feet of buffer had virtually no
T'$S__c.,b~'c~e~r~tions. The suspend~dsol~ds concentr~on at- Site F dec3-easect sligi~tly wit
oVeralt buffer strip d[Lm~nce, except far a rise at 75 feel Here, again, m~s.s conditions
persist in this particular region of the buffer due to a lack of ground cover, resulted irt
"nly a one perceat decrease in TSS c~ncentrafion in the the tirol 75 f~.~ 'l'he remaining 100
_-,~% 9f buffer remoYad mi a~;Icrrtion~ 5~ percent of T~. -- ...... - - "
('Virtu) uo.r,,~uaouoo d
Pollutant reductions per unit length of.buffer demonstrated in this project are not as
impressive a~ some ot tt~e buffer and filter strips stu..di, ed by others. For example, Dayie and
Stanton (1977) showed th~ a forest buffer strip length of only 12.5 feet was required to
reduce soluble P concentra~ons by 99 percent on a 30 pertain, slope. Altt~ough the slope
was substantial at their experimental buffer strip, there was also a thick, con.siaer¢ grouncl
cover o! decomposing organic matter. Much of the reason that they showect su~ m.a~d'
removals was due to the highly elevated nutrient and sec~ent level of the manure.applied.
On the average, soluble P concentra~ons ented~ their buffer strip were 7.5 times greater
than total P concentrations entering the buifer sajps in this project, x
Only Site E. which generated the highest P and TSS vel_ ues for this project, ~ed
removals approaching those ob~ned by _Doyle a~. Stanton.: I.n just_ 75_f _e~_~_t_h~e_.?n and TSS
concentrations'were reduced by 94 and 97 percent, respect~vety. I ne r' reaucao at Site E
atso matched well with resee, rch by Diilaha, et aL (1985), who found that 30 'feet of grass filter
strip removed 69 percent of the incoming P, cmnpared to 68 percent for the first 25 feet of Site
E in this project. However, they reported a removal of 91 percent of the TSS, while Site E
showed only a 47 percent reduction in 25 feel Still. it seems that for all four sites that 75 teet
was =adequate to reduce entering P concentrations to the level found.at.the c.o. ntro! site.
(Figure 2). For TSS, only two sites (B and E) produced concentrations s~mitar to the control
site after 75 feet..The other two sites (A and F) remained a?. o. ve _the.co..ntroL.
sites saw a rise ~n TSS after 75 feet due to exposed so~l un the miner stop. I nus, me
condilJon of the buffer strip seemed to be ju~ as important as the length.
' These results also suggest a correlalion between incoming pollutam load and buffer
strip effectiveness. I, fact, despite the grea?.po~ co. nce.n. _tr~__r? gene~_ ?_ _at~;~_e~e~.
with construction, e=tJng vaJues were ray...amaar, x_or co,n~s~u_caon..an.a no.n ~-?o~__n~_. ~n_.~_
The effect of co~ction activity on genera=on oz t' aha 1:5:5 aha me suosequen[
effectiveness were demonstrated at Sites E ~,nd F (Figure :~). Site E with ongoin, g
construction generated 3.8 times the P and 4.6 times the amount of TSS produced from the
existing house at Site F. Average exiting P concentra~ans were almost identicN, az both sites
(0.57 vs. 0.58 mg/L)'while the exiting TSS concentration was slightly higher from the buffer.
strip at Site E (237 vs. 175 lng,q-). This resulted in Site E having a 94 percent remavaJ
efficiency for both P and TSS, whereas.. Site F had only a 76 and 7.9, percent removal of P...ancl.
TSS, respectively. This provided a good test of buffer strip effecUveness during the cr~cat
buL'lding construction phase, when erosion potential is highest.
The data showed that although canstmcaon practices increased the P and TSS load
to the buffer strips, the buffers were able to absorb the increased pollutants effectively.
However, if erosion control were practiced effectively at construction sites, the burden on the
buffer strips would be minimized and less buffer strip may be nec~l_ ed to p.mt.e.ct watec
For example, at a buffer strip distance o! 25 feet, the average
times greater at Site E than at Site F.
The influence o~ grass ~ver was monitored at Site A and 8, ale both sites were se?ecl
to lawn in ~k t~mely la~hlon- Rgum 4 shaw= the P and T~$ levels during four storms priori=
the lawns becoming established and three storms after the lawns were in place. The
difference in P was made even more diam;~tic by the heavy use of fertilizer by the
ho eo e ta ab sh their lawns.
Die,ce (feet) ~~ (feet)
l='~jum 3. The effect of active constru~on upon P a~d'l'SS concentrations through buffer..
Distance (feet)
.L Befom
---~,--, After
0 :~S 5o, 75 ~0o 12S150 175 200
Figure 4. The. influence of pla~t~ng grass upon P and 'I'SS concentration.
A~ interesting characteristic was exhibited by Site E due to the lack of eros[on control
on the construct/on site. As t~me elapsed, a~t in~eas/ng amount of buffer was needed, to
b~ing P amd TSS concentra~ons down to the control range. The 'sediment Iront' advanced
slightly with each storm. For example, Storm 1 required only 25 feet to reach control w~es.
However, 75 feet were requ~'ed for Storm 8. The lawn still had not been seeded by the end
of the project.
The impact of Slope on .butler strip effe~_e.._ss._to.~re~.m~ve ~P ~a~:l~T~S~,~m, ~v,~e~n~d~
(E ~d ~ ~ 1.4 t,m~ me ~un: g~ r .,.~ .. - .
5).
The data showed that steeper slopes have increased P and TSS being transported
levels at Sile I:, one ot me two steep s~tes m~,a~u,=~- . ,~.~- .-
Using the d~ta oblameo Im P '~ . -----, ,-- ---.-,-.~--- -,~:,~,- '-r was
_ ,~..--. .........~. ,,. sh-. ef..ener SlOpeS yms generazex] uy .~.~.u,~.,,.
--. ......... ,-- -. ...... ;,~ rir~nerlous cOrlCertl]-'dtlons7, rleii~uv~l.,
stmply ittnezem [o mu am=V=- ~,,-"' ~,
poautants, however, was not adversely affected by the steeper slope.s. In fact, the steep sites
had the lowest exiting concentra~ons- A closer examm~on o! the sites revealed that grotmd
cover was k'kely more important than site gradient. Despite being only 300 feet away from
Site F, ~e forest floor ~ Site E was .~fferent in ~ it.~ coy?red.
decomposing forest litter. This act.ed.?.'= .POtOu~.l~.e_r_L,. i_n._~_.e~,__n..g._t_~m~m-~ ~.~°n..,~t~.~e~'
ground c~ver in buffer strip ,ff. octwenes.s, just~ sou? oe_.nera~._Ot_,P
~-~--- · ..... :.---*-,~.,;on of flow clechanne]ization measures, eros _
devices, grass filter strips, crushed gravel dxiveways to tmprove permeabdity, buffenng ..o
local streams and ditches, and runoff storage devices.
lo. oo ~
7.00, ~ Steep Slope ~ 2SOO~ ;5 Steep Slope
IL /
g
/
.'
o.oo o 2s so ?s ,oo,~ ~so ~s zo
~~ (f~t) Di~e (fe~t)
Ftgure 5. The influence of slope upon P and TSS concentration
the P concentration ep. tefing me buffer strip in an ~arly starrrl was 24 t~mes greater ttmn the
concentration entering during the last storm monitored. This could be clue to severaJ factors.
First, the lawn had been planted and ferti~zed approximately one weeX prior to the ea~
storm, which was El<ely respons~le for much of !tEe elevated phosphorus. Also, the bare,
nutrient-rich topsoit was susceptible to erosion At this time. In cordmst, the lawn was weft
established by the end of the studY, thus sharply reducing P concentratian by retarding
erosion and acting as a natural'filter for the runoff, in tact, the last storm monitored had the
lowest entering T~ and P v~lues of any storm. The highest entering P ,and 'I'SS
· concentra~ons 'at all sites were for Storm 3, which occurred in late spring. Spring rain
conditions after ground thaw combined with constmcl~on activities to contn'hu~ substangal
amounts of secfa~ent and P to the residential runoff. In COntra.% entering P and TSS vaJues
were 17 times lower just one month eadier, during Storm 1. The ground, including most of
the sec~ment, was ~ frozen, al this time, thus inhibilJng sediment transport.
Summary
~ Results showed that the system of in-ground sampling cups provided an. excellent
comparative measure of pollutant reduction as a function of distance and between sites.
However, cat,on must be used in comparing data to other stucFms due to the use o! cr~eting
experimental design and sampling methods.
Buffer stxips cmn be an effective 9lethod of redu~ P and TSS concentrations in
runoff from residential developments..LFor most of-the cases studied, 50-75 .feet of
bn~sturbed buffer strip brought concentra~ons within or close to average control valu..~
Ideally. it is recommended that buffer strips be sized by a site inspec~an, ~lue to the
high variability between sites. Even buffer strips in similar locations can have venj cfafferent P
and TSS removal capab[T~lJes, due ta va~bles such as ground cover and soil sfn_ hiFdy.
Individual site visits can lead toa properly designed buffer strip for the site specific
conditions. Potential adverse factors, such as erodible so~ and steepn, ess, could be
mitigated by increasLr~ buffer strip length ar engineering mecli[ications. ~. seecl'tng lawns
early in the construction phase would reduce sediment loads onto/be buffer st~. These
practices can all contribute to increased buffer strip effectiveness. A combination of
engineering alternates together with' r= _hJral buffer sl:~ps may be the best solution.
References
American Public Health .Rs=od=t. ion (lgSg) Standard Methods for ~he E. zaminatfon of
Water and Wastewa~r. 17th Edition, .aPl-lA. .
Dennis, Jeffrey (1985) Phosphorus Export Imm .a Low-Dens~y Residential Watershe.d and
an Adjacent Fore, ed Watershed, p. 410-407, I_.n. Lake and Reservoir Management: vol 11.
Proc. North American ILaha Management Society Annual Conf.,.Washington, D.C.
Dillaha, T.A., J.H. Sherrard, and D. Lee (1986) Long-Term Effectiveness and Maintenance o! .
Vegetative Rlter Stzips. VPI-VWRRC-BULL 153.
t3oyle, R_C. 'az~c[ G.C. Staman (1 g7"~ Effect~e,ess of Forest and Grass Buffer S~ps ~
Improving the Water Qua[~ 0f M~ure Polluted'Runoff. Paper No. 77-2501. Presented at the
1977 Winter Meeting, ASAE. December 13-16, ~o. IL.
Moor~, ~L (1 git/) NA/J~S ./~.~em~! ~fl~. ~orth .Lmeric~-~ [~ Ya~gemem
Society, Washington,.D,C.
Acknowledaements
· Th~ activities on ~icfl ~is publicaion is based ~ere ~nance~ in .part by the
Depatment of Civil Engineering, University o! Maine, Maine Department of Enviro~
Protection. and the Department of the Interior, U. S. Geelog~a=al Sunm¥, through the
University of Maine Water Resources [nsE[~e Program. The contents of this pub~n do
not necessarily reflect the -views and policies of fha'Department Of ~he' Interior, nor does
menl~3n of trade names oz' comrne~ products cortstit~e their endorseme~ by the United '
States Government.
The authors wish ta tha.~ Jeff Dennis. Maine DEP. for his advice and support of
this proj&ct and W~aiam Haltema~, UM Department of M,3therna~cs, for his assistance in the
st~tisticaJ anaJy~s of the data. The laboraZory assistance of Donna Wzmp~, Mike Wil~ms,
James Wagner, and DaSd Henderson is also greatJy appreciated.
Application of Wetland Buffers - City of Mound Projects
,il
B0 \ 80 ', 80
L- 80__~ ._.,,,.-,_,,,_80__ / L ~ 80 I 80..
- --- ~ ~( .... O ;" ~ --.~ ~.-I
~N , ~ ~ ~ -.
~ jo~,s 8~_~ L__8~.~8o ! ',~ . '"'
i N0~16'E L ~ ~;~. 15.17
'~~ XS~o
'
. [/~ / ~ , ~ ~t'~ '~.- - ~! = -
· ' ~ 47.47 ....... ~,
~ ~ L~'o ..............
~ _ t~l~ w ~ , .. ~ ......
og
Supplemental Information
CITY OF MOUND
5341 MAYWOOD ROAD
MOUND, MN 55364-1687
PH: (952) 472-0600
FAX.: (952) 472-0620
WEB: www. cityofmound,com
October 16, 2001
Ms. Glenda Spiotta
Minnehaha Creek Watershed District
2500 Shadywood Road
Navarre, MN 55331
RE: Cooperative Agreement - City of Mound Surface Water Management Plan
Dear Ms. Spiotta:
The City is in receipt of a letter from Ms. Lisa Tillman dated October 9, 2001 requesting an update
regarding the status of the cooperative agreement between the City of Mound and the Minnehaha
Creek Watershed District for the Mound Surface Water Management Plan.
Please be advised that the draft agreement is being forwarded to the City Council for action at its
October 23, 2001 meeting. Additionally, it is also being reviewed as a discussion item at the City
Council workshop scheduled for October 22, 2001. As you are aware, the cooperative agreement
was reviewed by the City Council at its June 26, 2001 meeting and was subsequently tabled
pending additional review and discussion by City staff.
On behalf of the City of Mound, I would ask that you share this information with the MCWD
Board of Managers. If you have any questions regarding this letter or would like any additional
information, please feel free to contact me at 952-472-3190. Again, I appreciate the assistance we
have received from the MCWD regarding this project.
Community Development Director
pnntod on recycled paper
Minnehaha Creek Watershed District
Improving Quality of Water, Quality of Life
Gray Freshwater Center
Hwys. 15 & 19, Navarre
Mail:
2500 Shadywood Road
Excelsior, MN 55331-9578
Phone: (952) 471-0590
Fax: (952) 471-0682
Email:
admin @ minnehahacreek.org
Web Site:
www. minnehahacreek.org
Board of Managers
Pamela G. Blixt
James Calkins
Lance Fisher
Monica Gross
Scott Thomas
Malcolm Reid
Robert Schroeder
{Printed o~ recycled paper containing
al Beast 30% post consumer waste,
October 9, 2001
Kandis Hanson
City Manager
City of Mound
5341 Maywood Road
Mound, MN 55364
Dear Ms. Hanson:
We are completing final assessment of your City's local water management
plan. According to our records, the City of Mound Plan was conditionally
approved at the May 10, 2001 meeting of the MCWD Board of Managers.
The City was requesting authority over District Rules B - Erosion Control, C
- Floodplain Management, D - Wetland Protection, and N - Stormwater
Management. Until the conditions of approval are met, the Plan is not
formally approved and transfer of authority cannot occur. The conditions for
approval were as listed in the attached resolution.
If you could provide us with a written statement on City progress toward
meeting these conditions by October 16, 2001, we would appreciate it. We
plan on discussing the status of conditionally approved local water
management plans at the October 25, 2001 meeting of the Board of Managers.
If you have any questions please contact Glenda Spiotta at (952) 471-0590.
Sincerely,
Lisa Tilman
Cc: Sarah Smith, City of Mound
RECEIVEP
0CT 1 2 2001
MOUNU PLAt JNIN6 & INSP.
T:\0185\04X267\WMP Status letter Mound.doc
LOCAL WATER RESOURCES MANAGEMENT PLAN
0I
WHEREAS on June 12, 1997, the MCWD adopted amendments to its comprehensive watershed
management plan under Minnesota Statutes § 103B.231, which, as amended, details
the existing physical environment, land use and development in the watemhed and
established a plan to manage water resources and regulate water resource use to
improve water quality, prevent flooding and otherwise achieve the goals of Minnesota
Statutes Chapters 103B and 103D; and
WHEREAS the MCWD's comprehensive watershed management plan, as amended incorporates the
Rules adopted by the MCWD to protect water resources, improve water quality, prevent
flooding and otherwise achieve the goals of Minnesota Statutes Chapters 103B and
103D; and
WHEREAS the City of Mound submitted a local Water Resources Management Plan to the MCWD
for review and comment on May 2, 2000 that continued under an extended time frame
by agreement of the City and the MCWD; and
WHEREAS the MCWD reviewed the Plan in accordance with Minnesota Statutes § 103B.235,
subd.3, prepared comments and met with City representatives; and
WHEREAS the Metropolitan Council received the local Water Resources Management Plan and
provided its comments to the MCWD on September 1,2000; and
WHEREAS the City of Mound subsequently prepared revisions and submitted final revisions to
MCWD which incorporated MCWD review comments; and
WHEREAS the MCWD determined that the revised Plan is consistent with the MCWD Water
Resource Management Plan; and
WHEREAS the MCWD determined that the Plan meets the requirements for local planapproval set
forth in the MCWD's Water Resource Management Plan, including that the City has
demonstrated that draft official controls described in the Plan will protect the MCWD's
water resources at least as well as the MCWD's rules; and
WHEREAS the City does intend to assume regulatory authority for erosion control, floodplain,
preservation, wetland protection and stormwater management.
Resolution No. 06-2001 Approving City of Mound's Water Resources Management Plan
THEREFORE, BE IT RESOLVED that the MCWD Board of Managers hereby approves the Plan on
the occurrence of the following conditions:
1. Both local governments shall execute a cooperative agreement establishing
implementation responsibilities between the City and MCWD.
2. The City shall revise the Wetland Management Plan to state that the City will amend
the Plan and submit it to the MCWD for approval within four months or 120 days
after the MCWD provides the Wetlands Functions and Values Inventory and
Assessment results for wetlands within the City of Richfield.
3. City Ordinances:
a. City ordinances shall be adopted addressing the use of phosphorus fertilizer,
erosion control, parking lot/street sweeping, pet waste disposal, floodplain
alteration, wetland protection and stormwater management within 180 days of
plan approval.
b. Adopted city ordinances shall be in the final substantive form as submitted to
MCWD as included in the Mound Water Resource Management Plan with the
following provisions:
1. Activities will result in no net decrease in the 100 year flood storage capacity.
2. BMPs will be consistent with Rule N, specifications of the MPCA Manual
(Protecting Water Quality in Urban Areas) and its future revisions.
3. Water quantity control requirements will be consistent with Rule N, #4
(rate control)
4. Water quality requirements will be consistent with Rule N. #5.
5. Wetland buffers will be required for all wetlands impacted by filling or
excavation and for wetlands on sites with new development or changes in
development and floodplain alteration sites. -
6. Activities including but not limited to mowing, yard waste, disposal, and
fertilizer application shall not occur within the wetland buffer zone.
7. Wetland replacement where permitted shall occur within the same
subwatershed as the associated wetland impact:
8. Wdtten notification will be in accordance with Rule A, #5.
The City shall not otherwise amend the Plan before adoption.
~INALLY 1~1~ IT R~:9OLVI::D ~hat MCWD stab~ and consultants are directed to develop a cooperative
agreement with the City of Mound to be executed upon mutual agreement and MCWD
Board approval within six months of this date.
offered the following resolution and moved its adoption, seconded by
The motion to adopt Resolution No. 6 -2001 received
yeas and ~
Yea Nay Abstain Absent Yea Nay
BLIXT SCHROEDER
CALKINS REID
FISHER THOMAS
GROSS
nays as follows:
Abstain Absent
Upon vote, the President of the Board of Managers declared the Resolution No. 6-2001 adopted on this the
10", day of May, 2001.
I, Lance Fisher, Secretary of the Minnehaha Creek Watershed District Board of Managers hereby certify that
this is a true and accurate copy of the odginal Resolution No. 6-2001approved on the 10"' day of May, 2001, by
the Minnehaha Creek Watershed District Board of Managers during an official Board of Managers meeting on
that date.
IN TESTIMONY WHEREOF, ! have hereunto set my hand of said Watershed District this the 10th day of May,
2001.
Lance Fisher, Secretary
COOPERATIVE AGREEMENT
Between the Minnehaha Creek Watershed District
and the City of Mound
for Local Water Planning and Regulation
This Cooperative Agreement is made this __ day of ,200 l'by and between the
Minn6haha Creek Watershed District, a watershed district with purposes and powers as set forth at
Minnesota Statutes Chapters 103B and 103D ("MCWD"), and the City of Mound, a body corporate
and politic and a [home rule charter/statutory] city in the State of Minnesota ("City").
Recitals and Statement of Purpose
WHEREAS in 1997, the MCWD revised its comprehensive watershed management plan
under Minnesota Statues § 103B.231, which details the existing physical environment, land use and
development in the watershed and establishes a plan to regulate water resource use and management
to protect water resources, improve water quality, prevent flooding and otherwise achieve the goals
of Minnesota Statutes Chapters 103B and 103D;
WHEREAS the MCWD's comprehensive watershed management plan incorporates the
Rules adopted by the MCWD to protect water resources, improve water quality, prevent flooding
and otherwise achieve the goals of Minnesota Statutes Chapters 103B and 103D;
WHEREAS the City has developed a local water management plan under Minnesota
Statutes § 103B.235 that describes the existing and proposed physical environment and land use
within the City and sets forth an implementation plan for .bringing local water management into
conformance with the MCWD's comprehensive watershed management plan;
WHEREAS on May 1, 2001, the MCWD Board of Managers conditionally aPProved the
City's local water management plan by adoption of Resolution 06-2001, which resolution is
~hed and incoq~orated herein;
WHEREAS the May 1, 2001 local plan approval was condition on fulfillment of the terms
set forth in Resolution 06-2001;
~~AS the City within 120 days of execution of this Cooperative Agreement will adopt
and implement its local water management plan and within 180 days will adopt all ordinances
identified in. Resolution 06-2001 as necessary for the Board of Managers' finding that the City's
official comrols a~¢ as prot~-'~ive of the water resource as the MCWD's;
Wt-IE~, the MCWD and City desire to memorialize their respective roles in
impleme~ng water resource protection and management within the City;
NOW THEREFORE it is mutually agreed by and between the parties that they enter into
.this Cooper~ive Agreement in order to document the understanding of the parties as to the roles and
r~ponsibilities of each party.
CLL-I~3~2
MU2204
1.2
1.3
The City may exercise all present and future authority it otherwise may possess to issue
permits for and regulate activities affecting; water resources within the City.
The City is solely responsible for erosion control, flOod plain alteration, wetland protection
and stormwater management for land development within the City. The City will regulate
these activities in accordance with the City's approved local water management Plan and the
terms of this Agreement. The MCWD will continue to exercise its regulatory authority with
respect to all other subjects of regulation under its Rules.
On written confirmation to the MCWD that the City has adopted erosion conii'ol, flood plain
alteration, wetland protection and stormwater management for land development ordinances
as required by Resolution 06-2001 and said ordinances are in force, the City shall become
solely responsible for erosion control, flood plain alteration, wetland protection and
stormwater management for land development within the City. The City will implement the
ordinances in accordance with the City's approved local water management plan and the
terms of this Agreement.
1.4
Within 120 days of its receipt of the MCWD's wetland inventory and function & value
assessment for the City, the City shall review its local water management plan, submit to the
MCWD such revisions as the City believes warranted by the new information.
1.5
The City will not issue a variance for an activity that does not comply with an above-
referenced ordinance until the MCWD has approved the variance and proposed conditions.
On receipt of a request for a variance, the City promptly will transmit a copy of the variance
request, and supporting documentation to the MCWD for review.
1.6
The City will maintain a log of permits it grants pursuant to this Agreement, will provide the
log to the MCWD annually and will meet at least annually with the MCWD to review the
implementation of the City's local water management plan.
2.0 Responsibilities of the MCWD
2.1
The MCWD will continue to apply and enforce MCWD Rules E, F, and G "dredging,
shoreland and streambank improvements, and stream and lake crossings," within the City,
as applicable.
2.2.
The MCWD will continue to apply and enforce MCWD Rules B, C, D and N, "erosion
coatrol, flood plain alteration, wetland protection and stormwater management for land
development," within the City until the conditions in Paragraph 1.3 have been met.
2.3
The MCWI) will continue to apply and enforce Rule I, "Variances," when considering a
varian~ fi.om an above,referenced City ordinance. The MCWD will act on a variance
request pursuant to Paragraph 1.5 within 30 days of its receipt of the request.
2.4
The MCWD will perform a wetland inventory and a function & value assessment for the
City and .will provide the results to the City.
CLL-199360v2
MU220...4
2.5
2.6
2.7
2.8
The MCWD will exercise good £aith in its review and approval o£any revision submitted by
the City in accordance with paragraph 1.4, above.
The MCWD will meet with the City at least annually to review the implementation of the
City's local water management plan. . ·
The MCWD retains the right to enforce any and all of its rules in the event that the City is
unable or unwilling to carry out its obligations listed in Section 1.0 of this Agreement.
The MCWD retains all authority that it may possess under Minnesota Statutes Chapters
103B and 103D or any other provision of law, except as explicitly reposed in the City under
this Agreement, including but not limited to authority set forth in.Minne~ta Statutes §§
103B,211, subd. l(a); 103D.335 and 103D.341.
3.0 Conditions
The City's local water management plan shall be deemed finally approved by the MCWD on the
City's fulfillment of paragraph 1.3 above.
4.0 Amendment
This Agreement may be amended only by a writing signed by both of the parties.
IN WITNESS WHEREOF, the parties hereto have executed this Cooperative Agreement.
CITY OF
M]NNEHAHA CREEK WATERSHED
DISTRICT
By:
Mayor
By:.
President, Board of Managers
By:
City Manager
APPROVED AS TO FORM AND
EXECUTION
APPROVED AS TO FORM AND
EXECUTION
By: By:
Its Attorney
Its Attomey
CLL- 199360v2
MU220-4
Improving Quality of Water, Quality of Life
Gray Freshwater Center
Hwys. 15 & 19, Navarre
Mail:
2500 Shadywood Road
Excelsior, MN 55331-9578
Phone: (952) 471-0590
Fax: (952) 471-0682
Email:
admin @ minnehahacreek.org
Web Site:
www. minnehahacreek.org
Board of Managers
Pamela G. Blixt
James Calkins
Lance Fisher
Monica Gross
Scott Thomas
Malcolm Reid
Robert Schroeder
Pdntad ca recycled paper containing
at least 30% pest consumer waste.
INFORMATION ABOUT MCWD RULES & PERMIT APPLICABILITY
DATE: August, 2001
Projects requiring a permit from municiPalities and townships may also
require a permit from the Minnehaha Creek Watershed District (MCWD).
Some projects that do not require a city permit may still require an
MCWD permit. Please consult the following list to see if the subject project
requires a MCWD permit. Be aware that the list below encompasses the
most important Rules based on the major types of projects for which the
public has been obtaining permits. However, it is not intended to serve as a
complete list of our Rules. Please refer to our web site at
· www. minnehahacreek.org for the complete description of all of our Rules,
and to find application forms. Also, feel free to call the MCWD office if you
have any questions.
Rule B
·
·
·
Erosion Control:
Grading of 5,000 square feet or more
Stockpiling or excavation of more than 50 cubic yards of material
As of January 1, 2000 MCWD requires that all silt fence installed
be orange in color.
Rule C
Floodplain Alteration:
· Any activity that proposes to place fill of any type in a floodplain
associated with a lake, river, stream, wetland, or any other water
basin.
Rule D
Wetland Protection:
All projects associated with the draining, filling, or excavation of a
wetland
Rule E
Dredging:
All dredging in the beds, banks, or shores of any protected water
or wetland
Rule F
Shoreline and Streambank Improvement:
· All shoreline and streambank improvements, including but not
limited to rip rap, retaining walls, sheet piling, and boat ramps
· All sandblanket projects
Rule G
·
Stream and Lake Crossings:
Placement of roads, highways, or.utilities in the bed of a protected
water or wetland
\\SHARONS\PROJ ECTS\gen memos\Contractors.doc
Minnehttha Creek
Watershed District
Improving Qualiey of Water, Qualiey of Life
Gray Freshwater Center
Hwys. 15 & 19, Navarre
Mail:
2500 Shadywood Road
Excelsior, MN 55331-9578
Phone: (952) 471-0590
Fax: (952) 471-0682
Email:
admin @ minnehahacreek.org
Web Site:
www. minnehahacreek.org
Board of Managers
Pamela G. Blixt
James Calkins
Lance Fisher
Monica Gross
Scott Thomas
Malcolm Reid
Robert Schroeder
Printed on recycled paper containing
at least 30% pest consumer waste.
· Construction of a bridge or related crossing of a water, waterway
or wetland.
· Placement of a culvert or similar structure in the bed or channel of
a protected water or wetland
Rule N
·
Stormwater Management:
All residential, commercial, institutional, industrial, or public land
development projects that will increase the area of impervious
surface or change land contours to alter the drainage ways,
increase peak runoff rates, or affect the quality of stormwater
flows.
Single family homes, additions of garages, decks, etc. are exempt
from this rule but may require a permit under one of the other
rules.
Grading and excavating must not begin until a permit has been issued and
required erosion control measures are in place. Working without a permit
where required is in violation of MCWD Rules and is a misdemeanor subject
to penalty by law.
If there is any question whether your project requires a MCWD Permit please
contact District Staff.
For further information regarding rules and
permitting, please call the MCWD office,
(612) 471-0590 or go to the MCWD Internet
web page (www. minnehahacreek.org).
\~SHARONS\PROJECTS\gen memos\Contractors.doc
next-previous
Rules Definitions
General Rules Policy
Rules in PDF Format
Best Mgmt. Practices
Best Mgmt. Checklist
Urban Small Site BMP's
Statement of Need &
Reasonableness of
Proposed Rules
Revisions
MCWD Relationships
with Municipalities
proposed Rule
Revisions
Rule B, D, G, & N
Rule E
Dredging
Rule M
Proposed Lake, Stream,
and Wetland Buffers
MCWD Rules
Rule A
Procedural
Requirements
Rule B
Erosion Control
Rule C
Floodplain Alteration
Rule D
Wetland Protection
Rule E
Dredging
Rule F
Shoreline & Streambank
Improvements
Page 1 of 7
PROPOSED RULE M
Lake, Stream and Wetland Buffers
viou$ ~'
PROPOSED RULE M
PURSUANT TO MINNESOTA STATUTES §103D.341
(Redlined from 3-14-01 proposed rule)
View Background Information
DEFINITIONS
The following terms are added or amended, as indicated:
"Impervious" means unable to effectively absorb or infiltrate rainfall and snowmelt so
as to impede the entry of water into the underlying soil and refers to surfaces such
as, but not limited to, asphalt, concrete, shingle, wood and compacted gravel.
"Land-disturbing activity" or "land disturbance" means any disturbance to the ground
surface that, through the action of wind or water, may result in soil erosion or the
movement of sediment into waters, wetlands or storm sewers or onto adjacent
property. Land-disturbing activity includes but is not limited to the demolition of a
structure or surface, soil stripping, clearing, grubbing, grading, excavating, surface
disturbance related to tunneling, filling and the c. tc:c~c, stockpiling of soil or cc,'th
other erodible materials.
"Native plant community" means a community so listed at the time of Board permit
action by the Minnesota Department of Natural Resources, Natural Heritage and
Nongame Research Program.
"Pervious" means able to effectively absorb or infiltrate rainfall and snowmelt.
RULE B: EROSION CONTROL
A new paragraph 5(b)(8) is added as follows:
(8) Documentation that no vegetation or soils will be disturbed, and
no excavated, fill or construction material will be stockpiled, closer to
any identified public water or wetland than the following:
Stream ~ 513 feet
Lake
Natural Environment
100 feet
All Other 50 feet
Wetland
Up to 1.0 Acres
25 feet
1.0 Acre or Larger
50 feet
http://www.minnehahacreek.org/Permit_Rules/MCWD%20Rule%20M.htm 10/8/2001
next-previous
Rule G
Stream & Lake
Crossings
Rule H
I:nforcement
Rule I
Vadances
Rule J
Fees Charged in Certain
Cases
Rule K
Performance Bond or
Letter of Credit
Rule M
Proposed Lake, Stream,
and Wetland Buffers
Rule N
Stormwater
Management for Land
Development Projects
Page 2 of 7
Notwithstanding, if an applicant developing a sing/e-family
residential lot of one acre or smaller demonstrates that the
aDolicable buffer width would cause the proposed activity to become
infeasible or substan'dally more costly, the District will reduce the
required buffer width. The buffer shall be as wide as site conditions
allow and the permit may include additional conditions to offset any
reduced protection.
A new paragraph 5(c)(7) is added as follows:
(7) Soil stabilization measures shall provide for prompt and effective
stabilization under prevailing site conditions and seasonal factors.
Section 9 is amended to read as follows:
9. MAINTENANCE. The permittee shall be responsible at all times for the
maintenance and proper operation of all erosion and sediment control facilities. On
any property on which land-disturbing activity has occurred pursuant to a permit
issued under this rule, the permittee shall, at a minimum, inspect, maintain and
repair all disturbed surfaces and all erosion and sediment control facilities and soil
stabilization measures every day work is performed on the site, and at least weekly,
until land-disturbing activity has ceased. Thereafter, the permittee shall perform
these responsibilities at least weekly until vegetative cover is established. Fencing
of sufficient height and visibility to prevent land-disturbing activity from intruding on
temporary buffer shall be maintained between the buffer and land-disturbing activity
until that activity has ceased. The permittee shall maintain a log of activities under
this section for inspection by the District on request.
RULE M: LAKE, STREAM, AND WETLAND BUFFERS
1. POLICY. Natural vegetation bordering the bed and banks of waterbodies serves
a critical role in maintaining the ecological function of and societal benefits deriving
from those water resources. Purposes served by vegetative buffers include bank
and shoreline stabilization; erosion prevention; filtration of nutrients, sediments and
other pollutants from storm flows; protection of stream beds and banks and
mitigation of downstream flooding through moderation of peak flows both into and
within the resource; regulation of in-stream temperatures; preservation of aquatic
and terrestrial habitat; protection of scenic resources; and maintenance of property
values. The purpose of this Rule is to afford the greatest possible protection to the
water quality, flow regime and habitat of the surface waters within the District,
consistent with the interest in avoiding undue disturbance to established public and
private activities in littoral and riparian zones.
2. APPLICABILITY. The Rule applies as stated in this section.
(a) A buffer permit is required before undertaking activity that requires a
permit under Rule C, D, G or N of the District Rules, except as stated below.
(1) This Rule applies only to land adjacent to a public water as
defined at Minn. Stat. §103G.005, subd. 15, as amended; or a
wetland as defined at Minn. Stat. §103G.005, subd. 19, as
amended.
http://www.minnehahacreek, org/Permit_Rules/MCWD%20Rule%20M.htm 10/8/2001