HomeMy WebLinkAbout#08 - Irrigation Alternatives for Oak Land Middle School
STAFF REPORT
DATE: 3/4/25
REGULAR
TO: Lake Elmo City Council
FROM: Nathan Fuerst, ACIP, Consulting Planner
AGENDA ITEM: Review of Irrigation Alternatives for Oak Land Middle School Site
REVIEWED BY: Jason Stopa, Community Development Director
CORE STRATEGIES:
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☐ Managed Growth ☒ Resilient Infrastructure
BACKGROUND:
The Lake Elmo City Council conditionally approved a minor subdivision, conditional use permit, and
variances for the Oak Land Middle School project by Stillwater Area Public Schools (hereafter “School
District”) on October 1, 2024. As part of the City Council’s review and discussion, the Council
determined that it desired more information on the alternatives for irrigation on the Oak Land Middle
School Site. It revised Resolution 2024-106, conditionally approving the CUP, to include a 10th condition
requiring an assessment of irrigation alternatives for the site prior to final construction plan approval.
The School District provided a memo dated November 4, 2024, which provided some basic analysis but
lacked certain details on implementation of the irrigation options considered by the School District
including an estimate of rough costs for the options. City Staff have met with the School District’s team
and requested an update to the 11/4/24 memo be made to provide additional detail. The School District’s
revised memo was provided to the City on 2/28/25 and is appended to this memo.
Final construction plans were submitted by the School District’s team on February 13, 2025 for the Oak
Land Middle School site are currently under City review. Staff are seeking to understand if the City
Council feels that enough information has been provided School District’s updated memo, and if not,
what additional information is desired by the Council.
ISSUE BEFORE COUNCIL:
Does the City Council accept the revised Irrigation Alternatives Memo from Stillwater Area Public Schools
regarding the Oak Land Middle School Property?
PROPOSAL DETAILS/ANALYSIS:
Current Oak Land Middle School Irrigation:
The School District currently irrigates the Oak Land Middle School property by drawing from its well
which was first constructed in 1966. The area currently irrigated on the site is limited to the sports fields.
A figure has been provided by the school district indicated which areas on the property are irrigated during
the growing season.
Irrigation Alternatives Identified:
The 11/4/24 Irrigation Alternatives memo provided a basic assessment of the following alternatives for
irrigation on site:
1. Private well – The school could continue to use its private well, however, the School District has
indicated that this well is at the end of its useful life. Therefore, the School District would need to
construct a new well for the purpose of continued irrigation of its property.
2. Stormwater Reuse – This would involve retrofitting the existing and proposed stormwater
treatment systems. Currently, the school district uses infiltration basins which would be
supplemented with underground systems with the new school addition. To facilitate reuse, the
School District would need to reroute stormwater to a new storage tank with integrated pumping
and mainline improvements to serve the existing irrigation.
3. Rose Lake – The school could construct a system to utilize water from the nearby Rose Lake. New
irrigation improvements would be required in order to gather and then treat the water from this
source prior to irrigating with it.
4. Municipal Water Supply – The School District would utilize its planned connection to the City’s
water supply by connecting the school building, and therefore irrigation system, to municipal water.
The School District has identified the connection to the Municipal water supply as its strong preference.
This is due to the cost of either replacing its existing well or constructing the systems needed to reuse
stormwater or pull water from Rose Lake. The School District has indicated that there are health concerns
for stormwater reuse and pumping water from Rose Lake.
The School District submitted a memo on February 28, 2025, so an analysis was not possible in this report.
A verbal update and review will be provided by staff at the City Council’s March 4, 2025 meeting.
Irrigation Reuse Requirements and Implementation in Lake Elmo:
The City of Lake Elmo City Code does not require stormwater reuse for irrigation. However the City does
allow for a density bonus when single family residential developments incorporate stormwater reuse into
development plans. Over the last several years, the City has also seen stormwater reuse count towards
Valley Branch Watershed District (VBWD) permitting requirements.
As a result of focus on stormwater reuse in new development, the City of Lake Elmo has seen a number of
new residential and commercial developments incorporate these systems into their design. Several recent
examples include the Northstar and Wildflower residential developments, along with the Roers Lake Elmo
Multifamily and Bridgewater Village multifamily and commercial developments.
Over the past several years, the City of Lake Elmo has discussed whether it should require stormwater
reuse. This issue is more complex than simply adding a new standard to the City’s ordinance. If the City
chooses to revise its ordinances to require Stormwater Reuse, staff would need time to consider how this
could be implemented the best. Factors for consideration include, irrigable area, impervious area, soils on
a property, and other site specific issues along with considerations for the many different forms of
development.
Currently, staff are not aware of any municipalities in the Metro area that have this requirement. One reason
is that there are likely to be certain properties or sites where stormwater reuse is not feasible or practical.
One recent example is the At Home Townhomes project which did not use wet ponds, making stormwater
reuse infeasible.
Incorporating stormwater reuse is even more difficult for site expansions and could prove challenging
depending on the amount of retrofitting required to a site. It is easiest to incorporate stormwater reuse
systems in new developments with the benefit of being able to account for needs such as wet pond size and
location, along with areas for irrigation system pumps and mainlines.
FISCAL IMPACT:
Requiring stormwater reuse systems would come at a cost to developers and to the City. New development
that may not otherwise include the systems will incur added design costs in addition to the materials needed
for infrastructure like pumps and mainlines to connect throughout a project. It is possible that this
requirement could deter certain types of new or re-development projects. Down the road, private property
owners or HOA’s will be required to keep these systems operational. With a new code requirement, there
could be instances where the City needs to conduct enforcement leading to use of city staff time and
resources.
OPTIONS:
Relative to the School District’s Irrigation Alternatives memo, there are two options:
1. Require amendment to the School District’s Irrigation Alternatives memo.
2. Accept the Irrigation Alternatives memo as revised.
RECOMMENDATION:
Staff recommend that the City Council discuss any concerns with the information provided by the Stillwater
Area School District in its memo evaluating irrigation alternatives for the Oak Land Middle School site. If
additional information is needed, the Council should provide direction.
ATTACHMENTS:
• Resolution 2024-106 – CUP approval for Oak Land Middle School Expansion
• Oak Land Middle School Site Plan
• Larson Engineering Memo received February 28, 2025
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NEW ADDITION
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SHEET: C202SHEET: C201
SHEET: C204SHEET: C203
SHORELAND OVERLAY DISTRICT
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FIRE TRUCK SERVICE
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WOLD ARCHITECTS
AND ENGINEERS
332 Minnesota Street, Suite W2000
St. Paul, Minnesota 55101
woldae.com | 651 227 7773
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OAK-LAND MIDDLE
SCHOOL 2025-26
ADDITION AND
RENOVATION
820 Manning Ave N,
Lake Elmo, MN 55042
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Independent School
District #834
1875 Greeley Street South
Stillwater, MN 55082
NJN
MTH
11-12-2024
12246044
3524 Labore Road
White Bear Lake, MN 55110
651.481.9120 (f) 651.481.9201
www.larsonengr.com
C 2024 Larson Engineering, Inc. All rights reserved.
3524 Labore Road
White Bear Lake, MN 55110
651.481.9120 (f) 651.481.9201
www.larsonengr.com
Larson
Engineering, Inc.
Greg A. Buchal, P.E.
Date: Reg. No.:11.12.24 23793
I hereby certify that this plan, specifications or
report was prepared by me or under my direct
supervision and that I am a duly licensed
Professional Engineer under the laws of the
state of Minnesota.
ADDENDUM #3 DECEMBER 3, 2024 1
CITY SUBMITTAL FEBRUARY 13, 2025
SITE PLAN -
OVERALL
C2000
NORTH
40 80 160
PROJECT AREA CALCULATIONS
TOTAL SITE AREA:1,619,971 SF (37.19 AC)100%
IMPERVIOUS AREAS:
PROPOSED IMPERVIOUS AREAS:
SCHOOL ADDITIONS 30,267 SF (0.69 AC)1.87%
SIDEWALK/BIT. TRAILS 23,034 SF (0.53 AC)1.42%
PARKING/ROADWAYS 29,043 SF (0.67 AC)1.79%
TRACK 4,462 SF (0.10 AC)0.27%
EXISTING IMPERVIOUS AREAS:
SCHOOL 135,372 SF (3.11 AC)8.35%
SIDEWALK/BIT. TRAILS 21,864 SF (0.50 AC)1.35%
PARKING/ROADWAYS 114,535 SF (2.63 AC)7.07%
SPORTFIELDS/TENNIS COURTS/TRACK 120,827 SF (2.77 AC)7.46%
TOTAL SITE IMPERVIOUS 479,404 SF (11.01 AC)29.59%
OPEN SPACE:
REMAINING OPEN SPACE 1,140,567 SF (26.18 AC)70.41%
IMPERVIOUS WITHIN SHORELAND OVERLAY ZONE:
SHORELAND OVERLAY AREA 1,122,127 SF (25.76 AC)100.00%
IMPERVIOUS AREA WITHIN
SHORELAND OVERLAY 147,391 SF (3.38 AC) 13.14%
SYMBOL LEGEND
PROPOSED BITUMINOUS PAVEMENT,
SEE DETAIL 1/C700
PROPOSED TRAILS/FIRE LANE
BITUMINOUS PAVEMENT,
SEE DETAIL 2/C700
PROPOSED TRACK
BITUMINOUS PAVEMENT,
SEE DETAIL 3/C700
PROPOSED CONCRETE PAVEMENT,
SEE DETAIL 4/C700
PROPOSED HEAVY-DUTY
CONCRETE PAVEMENT,
SEE DETAIL 5/C700
NEW STOOP, SEE STRL/ARCH
SOIL BORING MARKER
PAVEMENT MARKINGS
-VEHICLE STALLS/ARROWS/CROSSWALKS
-BUS STALLS/NUMBERING
EASEMENT LINE
RIGHT-OF-WAY LINE
PROPERTY LINE
SB1
NOTE: THE CONCRETE JOINTS ARE SHOWN ONLY FOR
GENERAL REFERENCE TO SIGNIFY LIGHT DUTY
CONCRETE PAVEMENT. ACTUAL JOINTS SHALL BE
CONSTRUCTED PER PROJECT SPECIFICATIONS.
NO PARKING
Larson Engineering, Inc.
3524 Labore Road
White Bear Lake, MN 55110-5126
651.481.9120 Fax: 651.481.9201
www.larsonengr.com
MEMORANDUM
To: Nathan Fuerst, City Administrator, City of Lake Elmo
From: Greg Buchal, PE – Larson Engineering, Inc.
Date: February 27, 2025
Project: 12246044
Subject: Additional Submittal to City of Lake Elmo on Behalf of Independent School District
#834 for the Oak-Land Middle School 2025 – 2026 Additions & Renovations project,
located at 820 Manning Avenue North. (PID# 36.029.21.11.0002 and
36.029.21.11.0003)
Oak-Land Middle School - Additional Analysis of Irrigation Alternatives
The Conditional Use Permit application was submitted and approved by the City Council on
October 1, 2024. As one of the conditions of approval for the CUP, the School District was to
provide a list of alternative methods to supply water for irrigating a portion of the property. This
information was provided in November of 2024, and since then additional backup and elaboration
of these methods was requested. The information below is a response to this request and no
revision to the approved Conditional Use Permit is being requested. For context, the Conditional
Use Permit complies with the current ordinances and the scope of irrigation is to only irrigate
those areas currently being irrigated with no expansion planned.
The City Planner has requested that additional information and analysis be provided for three
items; irrigation of the athletic fields utilizing well water; irrigation of the athletic fields utilizing
water re-use from storage tanks; and irrigation of the athletic fields utilizing water re-use from
Lake Rose. Another option being considered by the School District is to not irrigate any of the
fields.
As indicated in the previous Memorandum to the City of Lake Elmo in November of 2024, the
School District has made connecting to municipal water a high priority for the Oak-Land Middle
School, due to potential future health and safety concerns, and ongoing maintenance costs related
to having well-water at the school. This current building addition project provides the
opportunity to improve that infrastructure at the school.
With a new municipal water service to the school building, the existing irrigation system for the
athletic fields could be utilized and very little improvements, modifications, or costs would be
incurred, since the existing connection for the irrigation water remains within the school building.
Rain sensors would be added to eliminate irrigation operation when rain events have provided
adequate water to the athletic fields. This is the School District’s preference and they understand
that irrigation restrictions could occur in times of drought and would abide by all City of Lake
Elmo related ordinances regarding water use for the athletic field irrigation.
Nathan Fuerst, City Administrator, City of Lake Elmo
Oak-Land Middle School
2 of 6
Site Data
The athletic fields that are currently irrigated by the School District are located on the northern
side of the school property and within the existing athletic track. The total area of these athletic
fields is about 297,000 square feet or 6.8 acres (see attached aerial photograph of the Oak-Land
Middle School site).
Current water use for irrigation of the athletic fields is about 15,980 gallons (2,136 cf) per day
(based upon well data averaging monthly use quantities). The well was constructed in 1966 and
has experienced more frequent repairs and maintenance over the past 10 years. The current well is
315 feet deep and the well is permitted through the Department of Natural Resources (DNR)
for use of up to 4.3 million gallons per year.
Irrigation Using Well Water
The first alternative reviewed is using well water to irrigate the athletic fields. The current
location of the existing well conflicts with the proposed improvements at the site that are a part of
the current building addition and renovation project. This and in consideration of the current age
and condition of the well, a new well would be required at the site. The DNR has indicated that
typically a new well to replace an existing well would be permitted as long as the water use did not
exceed that of the existing well. However, the DNR indicated this could not be assured in this
situation with the regional water issues. A Preliminary Well Construction Assessment Application
would be required by the DNR to evaluate the impacts of the well.
Assuming a new well of similar size, depth, and capacity was allowed for irrigation of the athletic
fields, well contractors have provided costs of $160,000 to install a new well. In addition to the
well costs, associated costs for related electrical for power to the new location and modifications to
the existing irrigation system would add additional costs of about $45,000, making the overall cost
for this approach to be about $205,000 (not including maintenance and operation costs).
However, as indicated previously the School District’s desire was to not use well water due to
potential future health risks. The Minnesota Department of Health (MNDH) when contacted also
mentioned concerns about potential health risks related to PFAS – Polyfluoroalkyl substances.
This contamination is a concern in the east metro area based upon the MNDH (see attached PFAS
Contamination Map). Review of Metropolitan Council PFAS maps indicates areas close to the
Oak-Land Middle School that have PFAS contamination.
Irrigation Using Water Re-Use with Underground Storage Tanks
Another alternative reviewed is re-using water stored within new underground storage tanks for
irrigation of the athletic fields. Permitting of re-use systems falls under several jurisdictions such
as the MNDH, Minnesota Pollution Control Agency (MPCA), DNR, Minnesota Plumbing Code,
and the Cities where the systems are located. This permitting could complicate the process and
design considerations of the systems. However, the MPCA and the City of Lake Elmo do have
guidelines for water re-use and for purposes of this review, we followed those general guidelines.
The basic components of the water re-use system consist of the water source (storage tank), a
pump or pumps to convey water through the system to the irrigation system, and filtering and
treatment of the water before re-use in the irrigation system (see City of Lake Elmo Standard
Drawing C-02). MPCA and City guidelines recommend filtering sediments and particulates from
the water and treating the water with UV light and chlorination to address health and safety
concerns.
Nathan Fuerst, City Administrator, City of Lake Elmo
Oak-Land Middle School
3 of 6
The difficulty with this type of system at this school site is the feasibly of collecting and storing
enough water for irrigation use. Roof water is typically the best location to collect re-use water
from since this source would not have significant amounts of salts, sediments, grass clipping, etc.
But much of the existing roof water at this site discharges on to the ground and various locations
around the building and is difficult to centralize and collect. With the current building project,
much of the new run-off and roof water is collected and will be infiltrated into the ground in
accordance with Valley Branch Watershed District (VBWD) storm water treatment requirements.
Incorporating a water re-use system would require additional catch basin structures and piping to
direct water to the underground storage tank rather than to the current treatment system.
To provide one inch of water over the athletic field areas would require a tank of about 32,000
cubic feet or approximately 239,000 gallons. A typical 2-year rain event would provide about
19,000 cubic feet (142,000 gallons) of water. Significant rain events would be required to fill the
storage tank and the irrigation system would likely need to be supplemented with another source
of water, such as municipal water. Historical data indicates that the average weekly rainfall would
produce about 0.88 inches per week or 85,000 gallons per week for the drainage area to the tank.
See attached Appendix A for a summary of the costs for this water re-use system.
Irrigation Using Water from Rose Lake
The third alternative reviewed is using water from Rose Lake for irrigation of the athletic fields.
Drawing water from Rose Lake would require permitting through the DNR, VBWD, and may not
be allowed. Assuming water can be taken from Rose Lake, the approach would be very similar to
that described above using underground storage tanks but using the water “stored” in Rose Lake
instead of underground storage tanks. The primary differences in this situation are additional
piping, pumps, and filtering to get water from Lake Rose to the treatment/re-use system, but the
underground tanks would not be needed. All of the treatment components would be the same.
However, runoff to Rose Lake could introduce salts and other contaminants not anticipated in roof
water. Rose Lake has the potential for PFAS contamination such that there are potential health
concerns with this source of water, and the potential for contamination of the soil from the
irrigation water. See attached Appendix B for a summary of the costs for this water re-use system.
No Irrigation
Another option being considered by the School District is to remove all irrigation from the school
site. Much of the site is currently not irrigated. Obviously, irrigation helps keep natural grass
fields more playable and resilient, and therefore more usable for school and community use.
Summary
While there are several options for how the fields at Oak-Land Middle School could be irrigated,
the current plan is to leave the existing irrigation system connected to the building water system.
With the connection of municipal water, the irrigation would then be supplied by the municipal
water. This has been the plan for the entire planning process with City.
At the request of the City, the School District has studied other options and their additional costs
for implementation.
1. Irrigate with City water (additional project cost $0)
2. Irrigate with a new well system (additional project cost $205,000)
3. Irrigate with captured rainwater (additional project cost $313,400)
4. Irrigate with water from Rose Lake (additional project cost $212,8500)
5. Discontinue irrigation (additional project cost $0)
Nathan Fuerst, City Administrator, City of Lake Elmo
Oak-Land Middle School
4 of 6
The School District is recommending that their project continue with irrigating the fields with City
water and that they would comply with City ordinances regarding the use of the irrigation system
just like other properties within the City.
Nathan Fuerst, City Administrator, City of Lake Elmo
Oak-Land Middle School
5 of 6
Appendix A
Water Re-Use with Underground Storage Tanks
Pump & Intake Components
▪ Pump & Motor, VMS, 10HP-208-230V/3Ph
▪ Pump Discharge Header 100HP
▪ Flow Meters
▪ Pressure Relief Valves
▪ Discharge Terminations
▪ Discharge Manifolds
▪ Inlet Drop Pipes
▪ Intake Manifolds
▪ Float Kits (3” HDPE Pipe)
Treatment Systems & Components
▪ UV Systems
▪ Discharge Filters
▪ Self-Cleaning Intake Screen
Control Panel & Components
▪ Control System
▪ Touch Screen Displays
▪ Surge Protection
▪ Optical Devices
▪ Electrical Enclosure (with cooling and heating)
▪ VFD’s
▪ Composite Enclosure
▪ Formed Steel Base
▪ Electrical Service
Storage & Distribution Components
▪ 6” PVC Sch. 40 Pipe (200 LF)
▪ Storage Tank (32,000 CF / 239,360 Gallons)
▪ Reducers
▪ Gate valves
Total Cost: $313,400.00
Nathan Fuerst, City Administrator, City of Lake Elmo
Oak-Land Middle School
6 of 6
Appendix B
Irrigation Using Water from Rose Lake
Pump & Intake Components
▪ Pump & Motor, VMS, 10HP-208-230V/3Ph
▪ Pump Discharge Header 100HP
▪ Flow Meters
▪ Pressure Relief Valves
▪ Discharge Terminations
▪ Discharge Manifolds
▪ Inlet Drop Pipes
▪ Intake Manifolds
▪ Float Kits (3” HDPE Pipe)
Treatment Systems & Components
▪ UV Systems
▪ Discharge Filters
▪ Self-Cleaning Intake Screen
Control Panel & Components
▪ Control System
▪ Touch Screen Displays
▪ Surge Protection
▪ Optical Devices
▪ Electrical Enclosure (with cooling and heating)
▪ VFD’s
▪ Composite Enclosure
▪ Formed Steel Base
▪ Electrical Service
Storage & Distribution Components
▪ 6” PVC Sch. 40 Pipe (600 LF)
▪ Reducers
▪ Gate valves
Total Cost: $212,850.00
STANDARD DRAWING NO.
LAKE ELMO
CITY OF LAKE ELMO
JANUARY 2022
C-02