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HomeMy WebLinkAbout20230104 Environmental Board Packet Combined CITY OF LINO LAKES ENVIRONMENTAL BOARD MEETING Wednesday, January 4, 2022 6:30 p.m. Council Chambers Please be courteous and turn off all electronic devices during the meeting. AGENDA 1. CALL TO ORDER AND ROLL CALL 2. PLEDGE OF ALLEGIANCE 3. APPROVAL OF AGENDA 4. APPROVAL OF MINUTES: November 30, 2022 5. OPEN MIKE 6. ACTION ITEMS A. Shenandoah Park Stormwater BMP Feasibility Study B. No Mow May 7. GENERAL UPDATES 8. ADJOURN Meeting guidelines on reverse side. City of Lino Lakes Environmental Board MEETING GUIDELINES Open Mike – The purpose of a Board Meeting is to accomplish the business of the city. When presenting at a meeting please remember to be respectful and follow these guidelines: • Please address the meeting chair. • State your name and address for the record. • Please observe a 4-minute limit. • The topic must relate to city business. • Open Mike is for items not on the agenda. • A spokesperson must represent a group of five or more – groups will have 8 minutes. • The Presiding Officer may limit duplicative presentations. • Remember, the meeting is to discuss city business only. Public Hearing – Held as a separate item of business on the agenda. The public hearing segment is your opportunity to tell the Board how you feel about issues scheduled to be heard. Typically, a hearing follows these steps: • The Presiding Officer (Chair or Vice-Chair) will announce the proposal to be reviewed and ask for the staff report. The presiding Officer shall maintain strict order and etiquette at all meetings. • Staff will present their report on the proposal. • Board members will then ask City Staff questions about the proposal. • The Presiding Officer will then open up the public hearing for anyone present who wishes to comment on the proposal. This is the time for the public to make comments or ask questions about the proposal. Comments should be limited to four (4) minutes unless further time is granted by the Presiding Officer. All comments should be directed to the Board as a body and not to any individual Board Member or City Staff Member unless permission is granted by the Presiding Officer. No person shall be permitted to enter into any discussion, either directly or through a member of the Board without the permission of the Presiding Officer. • After everyone in the audience wishing to speak has given his/her comments, the Presiding Officer shall close the public hearing. • The Board will then discuss the proposal. No further public comments are allowed. • The Board will then make a recommendation(s) and/or a decision. When you are called upon for your comments, please step to the microphone at the podium and state your name and address for the record. Occasionally, the Board may continue a hearing to another meeting before taking action. Meeting Etiquette The Environmental Board must preserve order and decorum while the meeting is in session. A resident shall not, by conversation or otherwise, delay or interrupt the proceedings or the business of the Board, nor disturb any resident or Board Member while speaking or refuse to obey the orders of the Board. Environmental Board November 30, 2022 Page 1 CITY OF LINO LAKES ENVIRONMENTAL BOARD MEETING 1. CALL TO ORDER AND ROLL CALL Chair Sullivan called the Environmental Board meeting to order at 6:30 p.m. on November 30, 2022. 2. PLEDGE OF ALLEGIANCE 3. APPROVAL OF AGENDA The agenda was approved as presented. 4. APPROVAL OF MINUTES Ms. Buchmeier made a motion to approve the October 5, 2022 meeting minutes. Motion was seconded by Mr. Jonathan Parsons. Motion carried 5-0. Ms. Ella McNulty made a motion to approve the October 26, 2022 meeting minutes. Motion was seconded by Lindsay Buchmeier. Motion carried 5-0. 5. OPEN MIKE Chair Sullivan declared Open Mike at 6:32 p.m. There was no one present for Open Mike therefore it was closed at 6:32 p.m. DATE: November 30, 2022 TIME STARTED: 6:30 p.m. TIME ENDED: 7:06 p.m. MEMBERS PRESENT: Ella McNulty, Lindsay Buchmeier, John Sullivan, Jonathan Parsons, Cassie Cavegn MEMBERS ABSENT: Shawn Holmes, Alex Schwartz STAFF PRESENT: Andrew Nelson, Tori Philippi Dana Rozan Environmental Board November 30, 2022 Page 2 DRAFT MINUTES 6. ACTION ITEMS A. Emerald Ash Borer Injection Program Mr. Nelson, Environmental Coordinator, presented the staff report. Emerald ash borer (Agrilus planipennis, EAB) is a non-native invasive beetle that is causing widespread ash tree mortality in much of the eastern half of the United States. Lino Lakes is within the heavily infested area in the metro. In the next few years, the vast majority of ash trees in the city will be killed, removed, or treated with insecticides. The City response to EAB with respect to public trees includes removals of boulevard ash trees, replacement of these trees with a diverse mix of species, and insecticide injections that allow the City to stagger removals over time. Mr. Nelson stated the EAB injection program was initially approved by the Environmental Board in October 2020, and City Council approved the program in December 2020. Continuing the program for another two years will be beneficial to the health of private trees and public trees. The City contracted with Rainbow Tree Care in 2021 and 2022 to provide discounted ash injections for city boulevard trees and private trees for interested homeowners. Mr. Nelson reviewed the benefits of the EAB injection program. The program offers a dependable treatment service that keeps trees healthy and safe for City work crews preforming removals. Rainbow Tree Care also distributes a postcard to all residents informing them about EAB, the benefits of injection, and provides a clear option for injections with contact information. The program provides the City with mapping and data for all trees injected (public and private) to assist in the EAB response planning. Mr. Nelson concluded that the initial two years of the EAB injection program have been successful. The City can continue the program even when all City boulevard trees have been removed in order to continue providing the benefits for private treatments. Mr. Parsons mentioned concerns that there will be an extra cost for removing trees that are already dead. Mr. Nelson confirmed that was correct for a lot of tree companies because the trees are brittle and more dangerous to work on after they’ve been killed by EAB infestation. Chair Sullivan questioned if the costs for private trees are out-of-pocket costs for residents. Mr. Nelson confirmed that was correct. Chair Sullivan asked if there are different costs for different size trees or if there is a standard charge. Environmental Board November 30, 2022 Page 2 DRAFT MINUTES Mr. Nelson stated there is a price per inch diameter for resident trees and a price for City boulevard trees. The City cost is lower partially because the company is working with one client and one bill for 100 trees, so there is less administrative work needed. Ms. Buchmeier asked if there will be other bids requested from other tree care companies in addition to Rainbow Tree Care. Mr. Nelson stated that Rainbow Tree Care will be one of the companies along with another one or two. Mr. Chair Sullivan made a motion to recommend to City Council to continue the EAB injection program for City and private trees. Motion was supported by Ms. McNulty. Motion carried 5-0. B. Ash Removal Plan for Winter 2022-2023 Mr. Nelson, Environmental Coordinator, presented the staff report. Mr. Nelson presented two graphs, which explained the cumulative costs of treatments over time for a single tree, and another for the 200 trees left for the City to remove and replace. The graph explained the difference between EAB treatment cost versus the remove and replace cost for both private trees and City trees. For homeowners that value the tree, the services, shade, and aesthetics, it might be worth about $100 to $200 every two years to keep the tree. At the City scale, we have around 200 boulevard ash trees left and maintaining them into the future is not the most cost effective option. The strategy that the City is using will result in a diverse mix of species that will be more resistant to future pests and pathogens and will also have no ongoing treatment costs. Mr. Nelson presented the ash tree removal plan for winter of 2022-2023. Of the remaining 200 boulevard trees left, City staff will remove 37 trees. The Parks crew will remove 23 trees, and 14 trees will be removed by contractors. The boulevard trees on Stallion Lane have two trees per frontage, which the City standard is one tree per frontage. Once City staff removes the ash trees on this street, they will not be replaced. These trees will be easier to remove because they are smaller and require less equipment. The larger trees that will be removed on Quarterhorse Court require more equipment, yet are still attainable to remove by the City. Contractorswill handle more technical jobs, such as the trees on Red Clover Lane. Contractor removals are necessary when there are more obstacles and risk of property damage around the tree. Chair Sullivan questioned why we do not replace the trees on the frontage. Mr. Nelson stated thatthe City standardis one tree per frontage in developments that are part of the boulevard tree program. Chair Sullivan asked if staff has encountered any negative feedback from residents that aren’t receiving replacements. Environmental Board November 30, 2022 Page 2 DRAFT MINUTES Mr. Nelson responded that he had not received complaints, but would explain the City policy if questions did come up, noting that the residents on Stallion Lane did still have one boulevard tree per house. 7. UPDATES A. General Updates Mr. Nelson stated that he would provide an annual forestry report for 2022 at an upcoming meeting after submitting information for the Tree City USA program. Mr. Nelson also noted that there is a tree sale advertisement in the City Newsletter, which is a good program for residents who are losing a lot of trees to EAB. The tree sale occurs every year during the winter and the City usually sells about 100 trees per year. B. Recycling Updates Ms. Philippi provided an update that an average of 197 cars showed up at the last three months of Recycling Saturday for All Appliance Disposal. An average of 69 cars usedFirst Choice Document Destruction for paper shredding. There are now 472 participants in the organics program. Ms. Philippi stated that the Solid Waste Abatement Advisory Team meeting took place October 26, 2022 and provided a brief summary of this meeting. Ms. Philippi presented an overview of the parks recycling situation at each park in the City. Of the 22 parks in the City, 21 have garbage services and 41 bins in total. Next to most of the garbage bins are blue bins with a green cover for recycling. There are 19 parks with recycling services and 34 containers in total. During the summer, garbage and recycling bins are emptied every Monday mornings by the Parks department. The emptied materials are then bought to the dumpsters at Public Works. The Parks Department gave feedback that there is some cross contamination in the recycling bins. Depending on the amount of contamination in the bins, staff will either pick out the contamination or throw away the entire bag. Chair Sullivan asked if there are any instructions on the recycling containers, and if the staff ever considered adding labels. Ms. Philippi replied that there are no labels on the containers, but there are stickers available from the County that say no plastic bags. Environmental Board November 30, 2022 Page 2 DRAFT MINUTES Ms. Buchmeier asked if it is possible to add recycling bins to the parks that only have garbage bins. Ms. Philippi responded that they had asked the County for six more bins that are then placed by Parks staff based on use. Chair Sullivan asked for an update on Sunrise park dumpster for composting. Mr. Nelson responded that the organics bin is on hold for that site because some residents were concerned about the smell and seeing it from their house. Staff is hoping to get the compost dumpster in a different location to be able to use the $30,000 grant. Mr. Parsons asked if we will lose the grant money if it is not used. Mr. Nelson confirmed that they will lose the grant money if the compost site is not constructed. 8. ADJOURNMENT Chair Sullivan made a MOTION to adjourn the meeting at 7:06 p.m. Motion was made by Ms. Buchmeier and seconded by Mr. Parsons. Motion carried 5-0. Respectfully submitted, Dana Rozan – Office Specialist 1 ENVIRONMENTAL BOARD AGENDA ITEM 6A STAFF ORIGINATOR: Andy Nelson, Environmental Coordinator MEETING DATE: January 4 th, 2023 REQUEST: Motion to Accept Shenandoah Park Feasibility Study and Support Implementation of Improvements TOPIC: Shenandoah Park Feasibility Study INTRODUCTION Staff is requesting Environmental Board recommendation to accept the Shenandoah Park Feasibility Study and support future implementation of improvements. BACKGROUND In 2009-2010 the Rice Creek Watershed District, in partnership with the Anoka Conservation District, completed a Subwatershed Assessment focusing on Rice Lake in the Rice Creek Chain of Lakes. The purpose of the study was to identify potential subwatershed water quality projects to reduce runoff volume and sediment/nutrient loading to Rice Lake. The study identified Shenandoah Park as a prime candidate for additional study in advance of developing a large capital improvement project. A private ditch system maintained by the City runs through the park, under Birch Street, and discharges into Rice Lake. The ditch serves as the primary stormwater outlet for the residential neighborhood extending south to Coyote Trail. A majority of the park area is comprised of partia lly drained wetland. Staff is of the opinion that opportunity exists for a restoration project that would enhance water quality and provide for an improved greenway element to the park. The City Council approved Resolution 22-33 on March 14th, 2022 that authorized WSB and Associates to complete a Best Management Practices (BMP) Feasibility Study for Shenandoah Park. Rice Creek Watershed District partnered with the City through a 50% cost match and through providing resources to aid in the completion of the study. The final report was completed on December 7th, 2022. The study provides valuable information that will be used should the City and RCWD pursue external grant funding for a water quality improvement project in Shenandoah Park in the future. Of the four concepts described in the report, concepts 3 and 4, when combined, provide the greatest benefits to water quality, wetland improvements, recreational opportunities, and habitat improvements. These concepts also minimize the cost per pound for phosphorous removal, 2 while maximizing the total phosphorous removed. With these concepts, there is also room for greenway system benefits that could increase trail connectivity between Arrowhead Drive and Birch Street. Future implementation of the concepts may include a grant application to BWSR and a local match shared by RCWD and the City. ENVIRONMENTAL DIRECTION Staff recommends acceptance of the report and supports future improvements based on concepts 3 and 4 as described in the report. Staff is seeking Environmental Board acceptance of the Shenandoah Improvements Feasibility Report and support for future improvements to Shenandoah Park based on concepts described. ATTACHMENTS: 1. Shenandoah Park Aerial Photo 2. Shenandoah Improvements Feasibility Report TotemTrlShenandoah ParkTotemTrlHokahDr RiceCt Arrowhead Dr T o m a h a w k C t Arrowhead Dr Legend Address Labels Parcels City Mask December 27, 2022 Map Powered By Datafi ± 1 in = 105 Ft Shenandoah Park Aerial Photo Shenandoah Improvements Feasibility Report December 7, 2022 Prepared for: City of Lino Lakes 600 Town Center Parkway Lino Lakes, MN 55014 WSB PROJECT NO. 018901 -000 Shenandoah Improvements Feasibility Report City of Lino Lakes, MN WSB Project No. 018901-000 T able of Content s 1.0 Introduction ............................................................................................. 1 2.0 Project Location ....................................................................................... 1 3.0 Site Description ....................................................................................... 1 4.0 Identification of Issues .............................................................................. 4 4.1 Lino Lakes Chain of Lakes TMDL ............................................................ 4 4.2 Invasive/Nuisance Vegetation ................................................................. 4 4.3 Inefficient Use of Space ......................................................................... 4 4.4 Floodplain ............................................................................................ 4 5.0 Modeling Methodology .............................................................................. 5 6.0 Concept 1 ................................................................................................ 7 6.1 Modeling Results ................................................................................... 9 6.2 Construction Estimate ............................................................................ 9 6.3 Permit Table ........................................................................................ 10 7.0 Concept 2 ............................................................................................... 10 7.1 Modeling Results .................................................................................. 12 7.2 Construction Estimate ........................................................................... 12 7.3 Permit Table ........................................................................................ 13 8.0 Concept 3 ............................................................................................... 13 8.1 Modeling Results .................................................................................. 15 8.2 Construction Estimate ........................................................................... 15 8.3 Permit Table ........................................................................................ 16 9.0 Concept 4 ............................................................................................... 16 9.1 Modeling Results .................................................................................. 18 9.2 Construction Estimate ........................................................................... 18 9.3 Permit Table ........................................................................................ 19 10.0 Summary/Recommendation .................................................................... 19 Shenandoah Improvements Feasibility Report City of Lino Lakes, MN WSB Project No. 018901-000 Page 1 1.0 Introduction This report provides the City of Lino Lakes and the Rice Creek Watershed District (RCWD) with a series of four (4) conceptual designs and associated water quantity and quality models for implementation of best management practices (BMPs) within Shenandoah Park. These designs address water quality within an aged part of the City of Lino Lakes’ stormwater conveyance system draining to Rice Lake (AUID 02 - 0008 -00) which was listed as impaired for nutrients (total phosphorous) in 2010. Shenandoah Park was identified as a location for the installation of BMP retrofits to improve stormwater quality and reduce the volume of stormwater runoff as part of the Rice Lake Subwatershed Stormwater Retrofit Assessment completed in 2010. While this assessment provided site specific information and load reductions, the assessment report indicated that additional modeling was required for the Shenandoah Park stormwater improvements. In addition to developing t he conceptual designs discussed in this report, WSB also updated the existing InfoSWMM model used by RCWD, developed a P8 model, generated construction estimates for each of the four (4) concepts, and drafted a list of required permits from local, state, a nd federal entities. Through a series of meetings with City and Watershed District staff, WSB developed the four (4) concepts discussed in this report to meet the following goals: 1. Reduce total phosphorous (TP) and total suspended solids (TSS) loading withi n the ditch system and to downstream waterbodies, specifically Rice Lake . 2. Enhance the amenities, aesthetics, and recreational opportunities within the park . 3. Increase floodplain volume within the subwatershed . 4. Restore and rehabilitate park vegetation that w ill provide wetland functional lift . 2.0 Project Location The proposed improvements are located within the City owned parcels for Shenandoah Park, in the southwestern corner of Lino Lakes. The street addresses for the parcels containing the proposed work are 4 75 Arrowhead Dr on the south and 498 Birch St on the north. The surrounding properties are either residential or public right of way, with the exception of an existing stormwater pond east of the park. The project location is within the watershed for Rice Lake, which is situated approximately 1,800 feet north of the park. 3.0 Site Description The project is proposed on City park property. Currently the southern portion of the site is largely mowed turfgrass with a play area to the east and a grove of trees to t he north. Beyond this grove of trees, the majority of the site is vegetated with reed canary grass and nettle. A stormwater BMP was constructed in the upland northern portion of the project location to treat runoff from the reconstruction of Birch St in 2021. Shenandoah Improvements Feasibility Report City of Lino Lakes, MN WSB Project No. 018901-000 Page 2 The site is relatively flat, with an elevation difference of approximately 4 feet across the areas of proposed work. A main feature of the site, and driver of this project, is a drainage ditch that flows across the site from south to north. The ditch c omes in from a culvert under Arrowhead Dr and takes multiple 90 degree turns, running north, east, north, west, and finally north to a culvert under Birch St. The channel is well vegetated and there don’t appear to be any major areas of slope failure or excessive erosion. The upstream culvert from Arrowhead Dr comes in at an elevation of 886.15 feet while the downstream culvert under Birch St has an elevation of 886.05 feet . The 0.1 foot elevation difference across the ditch means it functionally behaves as flat and the drainage in it is essentially ponded and draws down as such. A site visit in September 2022 was used to record the existing natural resources and vegetation conditions of the site. The land north of the east -west portion of the ditch within t he project area consists of a Type 2 Fresh Wet Meadow wetland dominated by cattails, likely narrow -leaved (Typha angustifolia ). Reed canary grass (Phalaris arundinacea ) is dominant along the ditch and banks. The land south of the east -west portion of the d itch within the project area is a Type 1/2 Seasonally Flooded/Fresh Wet Meadow wetland dominated by stinging nettle (Urtica dioica ). An Aster spp. was also observed in low abundance throughout the site. The southeast stretch of the ditch has native red -osi er dogwood (Cornus sericea ) along it in moderate density. Overall, the herbaceous layer within the project area has little diversity. A map of the delineated wetland is below. Shenandoah Improvements Feasibility Report City of Lino Lakes, MN WSB Project No. 018901-000 Page 3 The very south end of the project area consists of a manicured turf area adjacent to a play structure. Just north of the play structure is an area of mounded soil (of an unknown origin) and mature tree growth. Shenandoah Improvements Feasibility Report City of Lino Lakes, MN WSB Project No. 018901-000 Page 4 To the west of this mound is an area containing tree species typical of a transition zone such as aspen (Populus tremuloides ). These trees are distressed and rotting. The west side of the turf area has large conifers that provide a screen from the adjacent residential home. Along the west edge of the project area are some existing box elder trees (Acer negundo ) and silver maple (Acer saccharinum ) and other small to medium sized diverse trees in good condition. 4.0 Identification of Issues The project area is sited at the intersection of a number of issues facing the City and RCWD. The proposed improvements can be leveraged to address multiple problems at once, the solutions provided by the project will balance the needs of these issues and provide a well -rounded benefit. 4.1 Lino Lakes Chain of Lakes TMDL Many of the lakes connected by Rice Creek in Lino Lakes fall under a TMDL for excess nutrients. This includes a 2010 TMDL for Rice Lake, the receiving water downstream of the project location. This TMDL estimates a 68 -80 percent reduction in TP loading to meet desired nutrient levels. This comes to an approximate reduction of over 9,300 pounds of TP. Much of this loading improvement may come from addressing upstream or internal phosphorous loading, however any reduction in TP is a net positive. As proposed, this project will result in a considerable reduction of TP loading to Rice Lake . 4.2 Invasive/Nuisance Vegetation The existing wetlands within the project area are domina ted by monotypic stands of cattails (likely invasive or hybrid) or stinging nettle with very low diversity and species richness. Along the ditch, invasive reed canary grass has prevented the growth of native vegetation. 4.3 Inefficient Use of Space The project space is currently very segmented, with the ditch, wetland, and park components separate from each other. There exists a great opportunity for a multifaceted approach at this site for water quality, ecological, floodplain, recreational, and educational be nefits. However, these benefits are either not being realized or only realized on an individual basis as -is. One major issue outlined by the City is a lack of connection between the well - developed trail system to the south and the trail system along Birch St to the north. Connecting these systems would also allow for better pedestrian access through the City and help to achieve its planning goals. 4.4 Floodplain As the downstream end of a stormwater system serving over 200 acres of drainage area, the site has h igh potential for flooding. As modeled in existing conditions, the 100 -year flood elevation is 892.15 feet . This high -water level approaches the lowest floor elevations of homes on Totem Trl. and Arrowhead Dr., putting these homes at risk of flooding. Prop osed project basins would lower this high -water level and decrease the risk of homes flooding. Shenandoah Improvements Feasibility Report City of Lino Lakes, MN WSB Project No. 018901-000 Page 5 5.0 Modeling Methodology One of the major components of stormwater design for this project is hydrologic and hydraulic modeling. This consists of modeling to underst and how much water is flowing through the site, what the peak rates and velocities of the flow reaches are, and how high flood levels will be. InfoSWMM software was used for this modeling in the project. RCWD has developed an InfoSWMM model for the project location and upstream stormwater infrastructure. A part of this project was updating the model based on City as -builts and stormwater system updates since its original creation. There were two existing ponds added to the model . BAL -012 -A and an unnamed po nd in Birchwood Acres Park. BAL -012 -A was assumed to flow west to Baldwin Lake but based on City as -builts it actually outlets south to pond RLA -012 -A and ultimately reaches Shenandoah Park and Rice Lake. The unnamed pond does not have as -built documents, so storage was estimated based on Anoka County LiDAR data flown in 2011. Another update to model existing conditions was a change to the outlet of the Shenandoah ditch under Birch St. The 36 inch RCP in the model was changed to reflect the 24 inch RCP that is there currently. Other smaller changes included updating basin storage based on as -built contours if available or 2011 LiDAR data otherwise. An overview map of the model area in question is below. Shenandoah Improvements Feasibility Report City of Lino Lakes, MN WSB Project No. 018901-000 Page 6 InfoSWMM modeling was also generated for the proposed project improvements. This was done to understand the benefits to outflow rates and flood levels in the pond system that may be realized as a result of this project. Generally, it was found that adding storage d ownstream in Shenandoah Park resulted in flow rate decreases under Birch St and reductions in flood levels through the system. These flood Shenandoah Improvements Feasibility Report City of Lino Lakes, MN WSB Project No. 018901-000 Page 7 elevation reductions were greatest at the project location but decreased in effect for ponds further upstream. The ot her major component of stormwater design for this project was in water quality improvements. This modeling seeks to understand what pollutant loading and removals can be expected based on the watershed characteristics and stormwater basins in the system. P 8 software was used for water quality modeling. This involved creating an existing conditions P8 model from scratch as there was not one already generated for this drainage area. Pollutant loading was determined based on subwatershed areas and impervious s urface fractions. Pollutant removals were determined based on pond as -built conditions. Under existing conditions, the drainage system upstream of the ditch removes nearly 22,500 lb of TSS and approximately 48.5 lb of TP each year. For proposed conditions, the P8 models were updated to include the proposed improvements with each concept. For the sake of water quality modeling, these BMPs were assumed to function as infiltration basins, where captured pollutant volumes are fully removed from the stormwater s ystem. Existing soils onsite are likely silty sands, providing an infiltration rate of approximately 0.45 in/hr based on the MN Stormwater Manual. However, based on past soil borings and County groundwater data, it is assumed inconsistent and minimal infiltration will be achievable in the basins due to the shallow depth of the water table in the area. Modeling conservatively assumed an infiltration rate of 0.01 in/hr, the minimum allowable in P8. Actual infiltration averaged over the year may b e higher than this based on water table fluctuations. Additionally, P8 modeling does not factor in pollutant removals from evapotranspiration and vegetation uptake, both of which will be emphasized with proposed improvements. Therefore, it is likely that p ollutant removals, TP in particular, will be higher than the results given but are difficult to quantify. The results of the modeling described above are summarized in the proposed concepts below. 6.0 Concept 1 Concept 1 is based directly on the proposed impro vements from the 2010 Rice Lake Subwatershed Assessment developed by the Anoka Conservation District. There are three wetland basins of roughly similar sizes that receive water from the ditch during medium to high flow events. Water is allowed to equalize between the basins and draws down very slowly over time via evapotranspiration and slow infiltration through the hydric soils. Captured water is kept in the basins after ditch levels draw down by virtue of one -way flap gates or duckbill valves on the inlet s from the ditch. Shenandoah Improvements Feasibility Report City of Lino Lakes, MN WSB Project No. 018901-000 Page 8 This system is not optimized for the full benefits that the site has to offer. It does not use all the space available that the City has to work with and does not provide any improvements to the ditch system. Shenandoah Improvements Feasibility Report City of Lino Lakes, MN WSB Project No. 018901-000 Page 9 Construction Cost - Option 1 Description Units Contract Quantity Unit Price Total Price Comments MOBILIZATION LS 1 $10,000 $10,000 ~10% of total budget COMMON EXCAVATION C Y 3000 $17.50 $52,500 Essentially all cut and removal from site RANDOM RIPRAP CL III C Y 20 $120.00 $2,400 For inlets 12" RCP L F 190 $90 $17,100 Based on OneOffice 12" RCP APRON EACH 2.00 $1,500 $3,000 Based on OneOffice FLAP GATE/DUCKBILL VALVE EACH 2.00 $3,000 $6,000 Based on OneOffice, no duckbill estimate STABILIZED CONSTRUCTION ENTRANCE EACH 1.00 $1,500 $1,500 Likely off Arrowhead Dr SILT FENCE L F 810 $3.50 $2,835 Need around grading + 40' to double up at culvert outlet EROSION CONTROL BLANKET S Y 3000 $3 $9,000 Placed on all pond slopes (top contour area - bottom contour area) SEEDING ACRE 1.4 $2,000 $2,800 Assume seeding occurs within full limits of disturbance plus over access route SEED MIX 25-151 LB 24 $10 $240 Seeding over access road SEED MIX 34-261 LB 40 $75 $3,000 Seeding wetland/pond areas 1.5" CAL TREE - BALLED AND BURLAPPED TREE 60 $400 $24,000 Based on OneOffice SHRUB - 5 GAL POT SHRB 100 $75 $7,500 Based on OneOffice 5 YEAR MONITORING/MAINTENANCE LS 1 $42,880 $42,880 20% Contingency $28,375 Total:$170,250 It does afford space for a pathway between th e wetlands and educational interaction points. Concept 1 generally works , but can be improved upon to achieve the greatest site benefits. 6.1 Modeling Results TSS Removal (lb/yr) TP Removal (lb/yr) Ditch 100 -yr HWL HWL Decrease (ft) 758 4.21 891.43 0.72 The results above are based on the P8 and InfoSWMM modeling for this project. The proposed wetland basins provided water quality improvements in accordance with their footprint and volume, TSS and TP removals shown are increases over existing modeled pollu tant removals. The drop in ditch high water level is also a function of basin volume. As such, Concept 1 shows the least benefits of all options due to its smaller basin footprint. 6.2 Construction Estimate The main driver of costs for all the provided concept s are excavation costs. Concept 1 calls for approximately 3000 cubic yards of excavation, driving about 50 percent of the construction costs. Other major costs include the construction of associated storm sewer and vegetation restoration across the site. T he total estimated concept cost, including a 20 percent cost contingency, is $170,250. Monitoring and maintenance of the site’s natural resources will be key to establishing a diverse, native plant community. Site maintenance includes a minimum of two sit e visits (spring and fall) for five years to conduct mowing and herbicide spot treatments, and supplemental seeding during one of the recommended five years. The cost of maintenance for five years as described is $34,380. Monitoring the vegetation each yea r would provide the C ity with an adaptive management approach to maintenance. The cost of monitoring one time per year for five years is $8,500. Shenandoah Improvements Feasibility Report City of Lino Lakes, MN WSB Project No. 018901-000 Page 10 6.3 Permit Table Permit Agency Timeline to Approval Federal Section 404 NWP 27 US Army Corps 60-90 days Local Rice Creek Watershed District Permit Rice Creek Watershed District 40 days Wetland Conservation Act No Loss Rice Creek Watershed District 60 days 7.0 Concept 2 Concept 2 builds on the wetland basins described in Concept 1, but with an emphasis on maximizing water quality benefits. The proposed basins are maximized to fill as much of the available space and provide the largest area for evapotranspiration and infiltration. One -way inlets are again proposed to allow water to flow in from t he ditch but prevent backflow once water levels draw back down in it. The ditch channel is not proposed to be shifted in this concept. This concept results in the greatest pollutant removal and increase in floodplain capacity. However, that comes at the co st of losing educational and recreational opportunities with the basins. In addition, maximizing basin volume does not provide much diversity in potential wetland improvements as much of it will consist of wet marsh conditions. Shenandoah Improvements Feasibility Report City of Lino Lakes, MN WSB Project No. 018901-000 Page 11 Shenandoah Improvements Feasibility Report City of Lino Lakes, MN WSB Project No. 018901-000 Page 12 Construction Cost - Option 2 Description Units Contract Quantity Unit Price Total Price Comments MOBILIZATION LS 1 $20,000 $20,000 ~10% of total budget, slightly lower b/c simpler COMMON EXCAVATION C Y 14750 $17.50 $258,125 Essentially all cut and removal from site RANDOM RIPRAP CL III C Y 10 $120.00 $1,200 For inlets 12" RCP L F 70 $90 $6,300 Based on OneOffice 12" RCP APRON EACH 2.00 $1,500 $3,000 Based on OneOffice FLAP GATE/DUCKBILL VALVE EACH 2.00 $3,000 $6,000 Based on OneOffice, no duckbill estimate STABILIZED CONSTRUCTION ENTRANCE EACH 1.00 $1,500 $1,500 Likely off Arrowhead Dr SILT FENCE L F 1,060 $3.50 $3,710 Need around grading + 40' to double up at culvert outlet EROSION CONTROL BLANKET S Y 3620 $3 $10,860 Placed on all pond slopes (top contour area - bottom contour area) SEEDING ACRE 2.6 $2,000 $5,200 Assume seeding occurs within full limits of disturbance plus over access route SEED MIX 25-151 LB 24 $10 $240 Seeding over access road, 120 lb/ac SEED MIX 34-261 LB 80 $75 $6,000 Seeding wetland/pond areas, 31.5 lb/ac 1.5" CAL TREE - BALLED AND BURLAPPED TREE 30 $400 $12,000 Based on OneOffice SHRUB - 5 GAL POT SHRB 100 $75 $7,500 Based on OneOffice 5 YEAR MONITORING/MAINTENANCE LS 1 $42,880 $42,880 20% Contingency $68,327 Total:$409,962 7.1 Modeling Results TSS Removal (lb/yr) TP Removal (lb/yr) Ditch 100 -yr HWL HWL Decrease (ft) 1,416 9.05 891.28 0.87 The results above are based on the P8 and InfoSWMM modeling for this project. The proposed wetland basins provided water quality improvements in accordance with their footprint and volume, TSS and TP removals shown are increases over existing modeled pollutant removals. The drop in ditch high water level is also a function of basin volume. As such, Concept 2 shows the greate st benefits of all options due to its largest basin footprint. 7.2 Construction E stimate Again, the main driver of costs is excavation, even more so for this concept since basin size is maximized . Concept 2 calls for nearly 15,000 cubic yards of excavation, dr iving about 8 0 percent of the construction costs. As with Concept 1, o ther major costs include the construction of associated storm sewer and vegetation restoration across the site. The total estimated concept cost , including a 20 percent cost contingency, is $410,000 . Monitoring and maintenance of the site’s natural resources will be key to establishing a diverse, native plant community. Site maintenance includes a minimum of two site visits (spring and fall) for five years to conduct mowing and herbicide spot treatments, and supplemental seeding during one of the recommended five years. The cost of maintenance for five years as described is $34,380. Monitoring the vegetation each year would provide the C ity with an adaptive management approach to maintenan ce. The cost of monitoring one time per year for five years is $8,500. Shenandoah Improvements Feasibility Report City of Lino Lakes, MN WSB Project No. 018901-000 Page 13 7.3 Permit Table Permit Agency Timeline to Approval Federal Section 404 NWP 27 US Army Corps 60-90 days Local Rice Creek Watershed District Permit Rice Creek Watershed District 40 days Wetland Conservation Act No Loss Rice Creek Watershed District 60 days 8.0 Concept 3 Concept 3 involves the most holistic improvements for the project, providing benefits to water quality, floodplain management, site ecology, recreation, and education. There are four proposed basins of varying size and depth, providing a variety of wetland environments and water levels. As with the other concepts, water is proposed to enter the basins via one -way inlets. The larger bas ins are proposed to be of greater depth, allowing for increased water quality volumes to be treated and further reductions in flood elevations. Another major component of this concept is the realignment of the ditch channel through the park . The proposed c hannel would be approximately the same length, but follow a more natural and winding route instead of the sharp 90 degree turns, reducing drastic velocity changes and the associated potential erosion. Concept 3 would also allow for the playground area in the park to be more easily accessible to Arrowhead Trail and also potentially afford some parking spaces in the space freed up by the ditch realignment. The concept also has potential space for boardwalks or trails through much of the park, provid ing recreational and educational opportunities through the large and varying spaces of restored wetlands, and providing a pedestrian connection from Arrowhead Tr. t o Birch St. Shenandoah Improvements Feasibility Report City of Lino Lakes, MN WSB Project No. 018901-000 Page 14 Shenandoah Improvements Feasibility Report City of Lino Lakes, MN WSB Project No. 018901-000 Page 15 Construction Cost - Option 3 Description Units Contract Quantity Unit Price Total Price Comments MOBILIZATION LS 1 $30,000 $30,000 ~10% of total budget COMMON EXCAVATION C Y 12500 $17.50 $218,750 Essentially all cut and removal from site COMMON EMBANKMENT C Y 600 $17.50 $10,500 Fill old channel RANDOM RIPRAP CL III C Y 20 $120.00 $2,400 For inlets 12" RCP L F 240 $90 $21,600 Based on OneOffice 12" RCP APRON EACH 5.00 $1,500 $7,500 Based on OneOffice FLAP GATE/DUCKBILL VALVE EACH 4.00 $3,000 $12,000 Based on OneOffice, no duckbill estimate STABILIZED CONSTRUCTION ENTRANCE EACH 1.00 $1,500 $1,500 Likely off Arrowhead Dr SILT FENCE L F 400 $3.50 $1,400 Need around grading + 40' to double up at culvert outlet EROSION CONTROL BLANKET S Y 9500 $3 $28,500 Placed on all pond slopes (top contour area - bottom contour area) SEEDING ACRE 3.6 $2,000 $7,200 Assume seeding occurs within full limits of disturbance plus over access route SEED MIX 25-151 LB 55 $10 $550 Seeding over access road and old channel, 120 lb/ac SEED MIX 34-261 LB 100 $75 $7,500 Seeding wetland/pond/channel areas, 31.5 lb/ac LIVE STAKES EACH 210 $3 $544 Stabilization along erosive edge of realigned ditch 1.5" CAL TREE - BALLED AND BURLAPPED TREE 55 $400 $22,000 Based on OneOffice SHRUB - 5 GAL POT SHRB 100 $75 $7,500 Based on OneOffice 5 YEAR MONITORING/MAINTENANCE LS 1 $42,880 $42,880 20% Contingency $75,889 Total:$455,333 8.1 Modeling Results TSS Removal (lb/yr) TP Removal (lb/yr) Ditch 100 -yr HWL HWL Decrease (ft) 1,297 8.37 891.30 0.85 The results above are based on the P8 and InfoSWMM modeling for this project. The proposed wetland basins provided water quality improvements in accordance with their footprint and volume, TSS and TP removals shown are increases over existing modeled pollutant removals. The drop in ditch high water level is also a function of basin volume. As such, Concept 3 shows the slightly decreased benefits compared to Concept 2, b ut they are still significant. 8.2 Construction E stimate Excavation costs still dominate the estimate project total under this concept, but less so than Concept 2. 12,500 cubic yards of excavation are proposed, but this would be slightly offset with the propos ed embankment volumes to fill in the old ditch channel. Earthwork estimates account for about 70 percent of total improvement costs. The total estimated concept cost, including a 20 percent cost contingency, is $455,350. It should be noted the construction estimate does not include potential recreational improvements such as a boardwalk or trail. Monitoring and maintenance of the site’s natural resources will be key to establishing a diverse, native plant community. Site maintenance includes a minimum of t wo site visits (spring and fall) for five years to conduct mowing and herbicide spot treatments, and supplemental seeding during one of the recommended five years. The cost of maintenance for five years as described is $34,380. Monitoring the vegetation ea ch year would provide the C ity with an adaptive management approach to maintenance. The cost of monitoring one time per year for five years is $8,500. Shenandoah Improvements Feasibility Report City of Lino Lakes, MN WSB Project No. 018901-000 Page 16 8.3 Permit Table Permit Agency Timeline to Approval Federal Section 404 NWP 27 US Army Corps 60-90 days Local Rice Creek Watershed District Permit Rice Creek Watershed District 40 days Wetland Conservation Act No Loss Rice Creek Watershed District 60 days 9.0 Concept 4 Concept 4 would consist of improvements largely focused on water quality benefits. Improvements would involve construction of an iron -enhanced sand filter (IESF) to treat the currently untreated runoff from Totem Tr., Hokah Dr., and Rice Ct., west of Shenandoah Park. This concept is proposed in conjunction with Concept 3, but it could also work in a modified capacity on its own or with Concept 1 or 2. All removals, floodplain benefits, and cost estimates factor in Concept 3 base elements and the IESF. As proposed, the IESF BMP would cover approximately 5,000 square feet with a basin bottom elevation of 887.4 feet . This elevation is based on a slightly raised invert of the outlet pipe for drainage coming off the roadway. Incoming stormwater would gravity flow through the filter media and outlet to the ditch via draintile. The manhole upstream of this outlet pipe is proposed with a 3 feet sump to provide pretreatment prior to flows reaching the IESF. Shenandoah Improvements Feasibility Report City of Lino Lakes, MN WSB Project No. 018901-000 Page 17 Shenandoah Improvements Feasibility Report City of Lino Lakes, MN WSB Project No. 018901-000 Page 18 9.1 Modeling Results TSS Removal (lb/yr) TP Removal (lb/yr) Ditch 100 -yr HWL HWL Decrease (ft) 5,688 19.75 891.30 0.85 The results above are based on the P8 modeling for this project. The IESF is proposed primarily for water quality benefits, as proposed it would have a negligible impact on floodplain volumes and water levels and therefore, they were unchanged from Concept 3. As shown in the results, this concept would greatly increase TSS and TP removals while taking up a relatively small footprint within the overall project area. Combined with Concept 3, TP removals are near 20 pounds per year. 9.2 Construction Estimate As wi th Concept 3, e xcavation costs still dominate the estimate d project. Earthwork quantities are slightly increased with the proposed IESF, but its volume is much less than the other wetland basins. Other major costs include the specialized iron - enhanced filt er media and replacement of storm sewer. The total estimated concept cost , including a 20 percent cost contingency, is $601,000 . Again, this construction estimate does not include potential recreational improvements such as a boardwalk or trail. Refer to t he budget table at the end of this section for the base construction cost line item breakdown. Monitoring and maintenance of the site’s natural resources will be key to establishing a diverse, native plant community. Site maintenance includes a minimum of two site visits (spring and fall) for five years to conduct mowing and herbicide spot treatments, and supplemental seeding during one of the recommended five years. The cost of maintenance for five years as described is $34,380. Monitoring the vegetation each year would provide the C ity with an adaptive management approach to maintenance. The cost of monitoring one time per year for five years is $8,500. Current design standards assume an approximate 10 -year lifespan for effective pollutant capture of an I ESF BMP. This lifespan can be extended with filter media replacement. The estimated cost of replacement is $45,000. This includes costs for removal of old media, installation of new iron -enhanced sand, and a 20 percent contingency. Shenandoah Improvements Feasibility Report City of Lino Lakes, MN WSB Project No. 018901-000 Page 19 9.3 Permit Table Permit Agency Timeline to Approval Federal Section 404 NWP 27 US Army Corps 60-90 days Local Rice Creek Watershed District Permit Rice Creek Watershed District 40 days Wetland Conservation Act De Minimis Exemption and No Loss Rice Creek Watershed District 60 days 10.0 Summary/Recommendation All concepts described in this report provide improvements to the existing site vegetation, water quality, and floodplain levels. However, each concept strikes a difference balance of the above in addition to providing potential consideration to recreational benefits for residents on Lino Lakes. The site stormwater benefits are summarized for consideration in the table below. Construction Cost - Option 4 Description Units Contract Quantity Unit Price Total Price Comments MOBILIZATION LS 1 $50,000 $50,000 ~10% of total budget COMMON EXCAVATION C Y 13000 $17.50 $227,500 Essentially all cut and removal from site COMMON EMBANKMENT C Y 850 $17.50 $14,875 Berm and old channel fill SELECT GRANULAR BORROW C Y 100 $30.00 $3,000 Filter sand FILTER MEDIA SPECIAL C Y 170 $175.00 $29,750 5% by weight iron enhanced sand RANDOM RIPRAP CL III C Y 30 $120.00 $3,600 For inlets/outlets 6" PERF HDPE PIPE LF 250 $24.00 $6,000 BMP underdrain 6" PERF HDPE PIPE CLEANOUT EACH 2 $500.00 $1,000 Underdrain cleanout 12" RCP L F 250 $90 $22,500 Based on OneOffice 12" RCP APRON EACH 6 $1,500 $9,000 Based on OneOffice 30" RCP L F 148 $150.00 $22,200 Based on OneOffice, replace pipe from Totem 30" RCP APRON EACH 1 $2,500 $2,500 Based on OneOffice FLAP GATE/DUCKBILL VALVE EACH 4 $3,000 $12,000 Based on OneOffice, no duckbill estimate 48" OCS EACH 1 $7,500 $7,500 Based on OneOffice, IESF outlet 60" MH L F 7 $1,000 $7,000 Based on OneOffice, replace in Totem GEOTEXTILE FABRIC S Y 800.00 $3 $2,400 Between IE sand and regular sand STABILIZED CONSTRUCTION ENTRANCE EACH 1 $1,500 $1,500 Likely off Arrowhead Dr SILT FENCE L F 900 $3.50 $3,150 Around filter and downstream of grading EROSION CONTROL BLANKET S Y 10000 $3 $30,000 Placed on graded slopes SEEDING ACRE 3.6 $2,000 $7,200 Assume seeding occurs within full limits of disturbance plus over access route SEED MIX 25-151 LB 55 $10 $550 Seeding over access road and old channel, 120 SEED MIX 34-261 LB 100 $75 $7,500 Seeding wetland/pond/channel areas, 31.5 lb/ac LIVE STAKES EACH 210 $3 $544 Stabilization along erosive edge of realigned ditch 1.5" CAL TREE - BALLED AND BURLAPPED TREE 55 $400 $22,000 Based on OneOffice SHRUB - 5 GAL POT SHRB 100 $75 $7,500 Based on OneOffice 5 YEAR MONITORING/MAINTENANCE LS 1 $42,880 $42,880 20% Contingency $100,154 Total:$600,923 Shenandoah Improvements Feasibility Report City of Lino Lakes, MN WSB Project No. 018901-000 Page 20 BMP Option Ditch 100 -yr HWL HWL Decrease (ft) TSS Removal (lb/yr) TP Removal (lb/yr) Existing 892.15 N/A N/A N/A Concept 1 891.44 0.72 758 4.21 Concept 2 891.29 0.87 1,416 9.05 Concept 3 891.31 0.85 1,297 8.37 Concept 4 891.31 0.85 5,688 19.75 A major component of assessing BMP cost efficiency is the estimated cost divided by the provided pounds of TP removal. The proposed improvements were evaluated with a 25 -year lifespan. Costs over the lifetime included full construction cost, 5 years of vegetation maintenance, annual BMP maintenance, and any major maintenance costs. These costs and the price per pound of TP are summarized in the table below. BMP Option Annual TP Removal (lb) Construction Cost 5 -year Vegetation Maintenance Cost Annual BMP Maintenance Cost Major O&M Cost 25-year Cost/Pound TP Concept 1 4.21 $170,250 $42,880 $100 $0 $2,049 Concept 2 9.05 $410,000 $42,880 $200 $0 $2,024 Concept 3 8.37 $455,350 $42,880 $200 $0 $2,405 Concept 4 19.75 $601,000 $42,880 $300 $45,000 $1,410 All concepts proposed provide improvements in varying degrees. Concept 1 provides lower benefits but comes at a lower cost and would entail a smaller amount of disturbance to existing site conditions. Concept 2 maximizes basin size and a ssociated pollutant removals, but at an increased cost and with no broader improvements to the park. Concept 3 provides large basin sizes, ditch realignment similar to a natural channel, and potential recreational benefits, but with a greater cost and major site disturbance. Concept 4 provides similar benefits in addition to the best cost per pound of TP removal, but at a significant upfront cost and higher long term maintenance needs. This report recommends the City consider the improvements in Concept 4. The proposed work w ould allow for high degrees of wetland improvements in large basins that would also serve to reduce flood levels. Ditch realignment would further serve to enhance these natural resources benefits while also providing options for a greenway trail system and educational opportunities around the merits of stormwater treatment and wetland ecosystems. Finally, the proposed IESF would provide exceptional pollutant treatment and the best price per pound of TP removed. With the wide degree of benefits and greatest price -quantified water quality improvement, Concept 4 would also be a strong candidate to receive grant funding to help the City offset its construction costs. However, WSB will be happy to support the City in pursuing further design of any concept propose d. ENVIRONMENTAL BOARD AGENDA ITEM 6B STAFF ORIGINATOR: Andy Nelson MEETING DATE: January 4th, 2023 REQUEST: Recommendation to City Council regarding No Mow May TOPIC: No Mow May INTRODUCTION Staff is requesting that the Environmental Board consider whether to support “No Mow May”. Board support of this initiative would include a recommendation to the City Council to proclaim “No Mow May”, which would permit residents to voluntarily delay lawn care until June by directing staff to not issue correction notices for tall grass and weed violations for the month of May. BACKGROUND Pollinator species are essential components of ecosystems. Many species of bees, butterflies, flies, beetles, and other pollinators are struggling to survive due to habitat loss, pesticide use, and other factors. We can help these critical species persist by improving their habitat and forage opportunities. The best way to improve habitat and forage opportunities for pollinators is to plant native plants. This includes early-flowering native trees such as willows, red maples, and fruit trees, and native herbaceous plants such as asters, coneflowers, goldenrods, wild bergamot, milkweeds, and sunflowers. Another way to increase habitat and forage opportunities for pollinators is to let flowers grow in turf grass lawns by simply not mowing in the month of May. “No Mow May” is a conservation initiative first popularized by Plantlife, a conservation charity in the United Kingdom. Bee City USA, an initiative of the Xerces Society, an international invertebrate conservation organization, has been promoting “No Mow May” with the support of a growing number of cities throughout the country. New Brighton, Edina, Vadnais Heights, Mankato, Rochester, and others have passed resolutions in support of this effort. The City can support “No Mow May” through a resolution directing staff to not issue correction notices associated with Chapter 904 of the City Code for tall grass and weed violations for the month of May. Enforcement of Chapter 904, which in part sets a height limit of eight inches for grass and weeds, would then resume in June. If a resolution is approved, residents who wish to take part in this voluntary program could print a sign to display in their yards to enhance the educational component of this initiative. The Bee City USA website https://beecityusa.org/no-mow-may/ has sign templates available for free. There are hundreds of pollinator species adapted to hundreds of native plant species in our area. While allowing non-native weed species to flower in lawns is no substitute for expanding the use of native plants, this program does aid in increasing public awareness about pollinators while shifting the aesthetic in favor of more natural landscaping methods. The Environmental Board recommended supporting “No Mow May” at the May 4th, 2022 meeting. The City Council, at their May 9th, 2022 Work Session opted to postpone the topic until 2023 to allow time for more information gathering and discussion. RECOMMENDATION Recommendation to the City Council on whether to support “No Mow May” in Lino Lakes.