Scott Watershed Management Organization 200 Fourth Avenue West Shakopee, MN 55379-1220 0 952-496-8054 Fax 952-496-8496 www.co.scott.mn.us
AGENDA Scott WMO – Watershed Planning Commission
May 24, 2021 4:00 p.m. Watershed Planning Commission Meeting Video Conference
I. Call to Order Action
II. Approval of Agenda and Meeting Minutes a. April 26, 2021 Minutes Action
III. Staff Reports a. Scott SWCD - TK Information b. Scott WMO - VS Information
IV. Ongoing Business a. Project Updates - RH Information b. Program Updates – MBE Information c. Wake Boats Information
V. New Business a. Public Hearing: 2020 MS4/SWPPP – Megan Tasca Action b. Kevin Koepp Grade Stabilization Application - RH Action
VI. Adjourn Action Scott Watershed Management Organization 200 Fourth Avenue West Shakopee, MN 55379-1220 952-496-8054 Fax 952-496-8496 www.scottcountymn.gov/wmo
Scott WMO – Watershed Planning Commission Meeting Minutes
April 26th, 2021
I. Call to order
Commissioner Weaver called to order the regular meeting of the Watershed Planning Commission meeting at 4:01 PM on April 26th, 2021 at Virtual Conference via Zoom.
Specific details and video of the entire April 26th, 2021 Scott WMO Watershed Planning Commission Meeting is available for viewing on the Scott County Website.
The video link can be viewed at: Scott WMO Planning Commission: February 22, 2021 - YouTube
II. Roll call
Members Present: Members Absent: Staff Present: Others Present: Pam Caselius Vanessa Strong Troy Kuphal Virgil Pint Melissa Bokman- Bruce Loney Rita Weaver Ermer Tom Wolf Brian Schmidt Ryan Holzer Mark Vierling Domi Archiebald Kevin Shea Joe Thill
III. Approval of Agenda
Motion by Commissioner Shea; Seconded by Commissioner Pint to approve the April 26th, 2021 Meeting agenda as amended.
The Motion carried unanimously for the Agenda to be approved as amended.
IV. Approval of minutes from last meeting – February 22nd, 2021.
Motion by Commissioner Vierling; Seconded by Commissioner Caselius to approve the February 22nd, 2021 Meeting Minutes as written and presented.
The Motion carried unanimously for the Meeting Minutes to be approved as written.
V. Public Comment
Vanessa Strong read the letter received by Maxine Hughes to the Commissioners during the meeting.
Letter: Wake Boats Submitted by: Maxine Hughes 1259 Maxine Cir. Shakopee, MN 55379
Commissioner Pint asked several questions regarding the issues presented in the letter. Staff was directed to bring additional information to the May meeting. VI. Staff Reports
SCOTT SWCD: Updates from Troy Kuphal ▪ Soil Health/Cover Crop Initiative – o Published 4 social media posts o Updated the cover crop strategic plan for 2021 o Provided Technical assistance to 1 landowner ▪ Clean Water Education Program (SCWEP) – o Held the annual SCWEP partnership meeting (Feb 10); finishing draft 2021 SCWEP annual work plan o Developed and launched marketing campaign for the 2021 SWCD raingarden webinar (was Apr 7) o Created native grass seeding fact sheet for landowners o Created and purchased materials for a homeowner chloride pollution kit o Purchased customized materials for proper pet waste outreach o Created and mailed postcards on SWCD ag services to 190 producers o Designed targeted postcard for PLSL and Sand Creek producers promoting CWF cost share availability o Created and launched a post-workshop survey for chloride workshop series for maintenance professionals ▪ Inventory and Assessment/Planning o Continued work on the Roberts Creek Sub-Watershed Assessment (SWA) o Identified and ranked best BMP applications produced by the Prioritize, Target and Measure Application (PTMApp) model o Created loading and source reduction maps for the final report o Zoning Support – County o Provided Dave Woestehoff with historical CUP information and guidance in conjunction with Scott County staff regarding procedures for transfer o Conducted a productive acreage determination and MinnFARM evaluation for 4 Winds Stables in coordination with CUP application review and letter of recommendation for a private riding arena ▪ Livestock Operation Assistance o Continued assistance for Dave Woestehoff NPDES permit application including Manure Management Planning o Water Quality, Groundwater and rainfall Monitoring o Please see presentation graph in WPC packet. o Tree Program o 33,500 Trees and 100 Native Seed Mixes sold o Approximately 1,400 trees still available for sale o Preparing for Native Plant Sale launch on May 1 o Cooperative Weed Management (CWM) Program o Closed out 2020 MDA Noxious Weed Grant o Awarded $2,000 for 2021 MDA Noxious Weed
SCOTT WMO: Updates from Vanessa Strong ▪ The staff has officially moved out of the East Government Center building. We have temporary workspaces in the new location until our area is finished. We will continue to telework for the remainder of the year. Once the building is completed, we will be moved to the third floor – this should take place in December 2021. ▪ One Watershed One Plan o The Board is very supportive: they were very supportive of our efforts with One Watershed One Plan and would like to move forward with that. They requested that we bring a resolution to the consent agenda in May. ▪ Unified Watershed Management Planning o The Board really hadn't had a chance to really discuss the strategy or goals. And so, we're working through all of that right now, as of this point in time. There is no one path forward that anybody's agreed upon for sure everything's open to how we might manage the different watersheds and how we might manage watershed in the county. Some key things are that we have kind of an official steering committee now, which are two members of the County/ WMO board, two members of the Prior Lake Spring Lake Watershed District Board and two members of the Soil and Water Conservation District Board that are kind of help helping to steer this and lead it and then make decisions and bring them back to their boards. And then there's also a technical or project management team, which is made up of myself and Troy Kuphal, SWCD and the new administrator for Prior Lake Spring Lake Watershed District. VII. Ongoing Business
Project Updates: Updates from Ryan Holzer ▪ Project Maintenance – Ryan met with our Public Works department on site. Our phase one streambank stabilization site had some erosion where one of the vertical logs snapped off. Today's visit was just to see if the Public Works Department could handle this maintenance activity as access is a little bit tricky. What we're proposing is rock down there to fill in the void in the structure. We looked at it today and showed them a path that we could use and they did not see an issue with doing that. We are getting so close to the planting season that it just doesn't make sense to do the maintenance now. It would also causes some compaction issues for the renter, that they won't be able to till the field before they plant it. So, we're thinking fall at this point. I'll confirm that with the landowner and the renter to make sure, but that will likely happen. I would think the worked would be done in the November/December 2021 timeframe. ▪ EPA Grant – the EPA grant is coming to an end. We are making sure that projects are being completed and funds are being used. So right now, I'm going through just seeing if there's any slippage in various tasks that we have in the grant, I believe we do have some amount, probably in the neighborhood of 5,000 to 10,000.
Program Updates: Updates from Melissa Bokman-Ermer • AIS Program – DNR announced its AIS Control Grant application period is open. This year it’s not a first come first served process as in the past. There are 11 days to submit applications (March 1). They indicate that applications that come in will be randomly ordered and selected by this order until all funds are spent. $400,000 available state-wide for treatment of CLP, EWM, flowering rush. It's a competitive grant. They didn't go into detail on how that random process worked, but I applied for all four lakes that we work on, Cedar, McMahon, O’Dowd and Thole. We were awarded the control grant for three of the lakes. McMahon was $2,475, O’Dowd was $3,247, Thole was $2,250. We've already gotten those contracts executed. • We're ready to go whenever I can start working on the pretreatment surveys. Secondly, for the last several years, when I would go out and do an aquatic plant survey, I would have to take paper forms. At every point I use a GPS and at every point I'd have to write down all the data, then I'd have to come back to the office or my desk, and I'd have to reenter in all this data into a spreadsheet to look at the data and create maps and send to the DNR. Well. Finally, this year ESRI, has come out with a new tool. I've been working with our GIS department who has put together now this application for me that I can use right on my smartphone. It's actually ArcGIS based. So, when I'm out on the lake, my map shows up, I can turn on tracking. I just go to every point and we throw the rake and I can enter in all the data right on my phone. Then when I come back to the office, I can look at that all immediately on GIS.
VIII. New Business – Annual Report and Newsletter Updates from Vanessa Strong ▪ Staff worked very hard to complete the annual report and newsletter. This is an annual requirement for the WMO that we must submit to BWSR to show progress on how we are achieving our goals. This is how we show progress towards achieving the goals in our work plan and in our Watershed Management plan; this is the annual check that we submit to BWSR to show how we are making that progress. The annual report is due to BWSR every year at the end of April. The report is there for you to read and review. If you have any comments, you can certainly submit them today. Or you can send them to me via email or call me this week. I do intend to submit it though by the deadline on the 30th. For this meeting, we are as staff asking the Commissioners to recommend report for approval of the report in order to submit to BWSR. Please use this link to view the report at full length: https://www.scottcountymn.gov/752/Reports-Documents
Updates from Melissa Bokman-Ermer ▪ Scott County falls within the ecoregion of the North Central Hardwood Forest. There are several different ecoregions, and water quality standards are created for each different ecoregion. Total phosphorus in shallow lakes, the water quality standard is 60 micrograms per liter, or 60 parts per billion. So any data is under that then, is meeting water quality standards, if it's measuring above that, then it's not meeting that water quality standard. Chlorophyll-a is 20 parts per billion standard for our ecoregion. Transparency, reading should be greater than one meter. For Cedar Lake, we've got quite a bit of data now from 2006 to 2020. (Displaying lake charts). What's interesting is that if you look at Cedar, transparency is pretty low, it's about 0.7 meters, so it's less than that one meter. When we look down at McMahon for 2020, you can see that the clarity decreased in 2020, as well, versus it kind of stayed about the same in 2019, on both lakes. 2020, the clarity decreased in McMahon also. What's interesting for both of those lakes is that total phosphorus stayed the same. But chlorophyll-a was reduced. It’s interesting that both of those lakes kind of had the same measurement reaction in 2020. If we look at O’Dowd as a comparison, O’Dowd the clarity did decrease a little bit in 2020. Transparency was decreased also on Thole. My thought on that, overall is that there was so much more boat action on the lakes that there was a lot more stirring up of the water and bottom sediment and that probably decreased clarity on all four lakes. What's interesting, O’Dowd and Thole total phosphorus went up. Thole is a lot shallower than the other lakes especially in the bays and the more open area. It was interesting that the clarity on all four lakes pretty much decreased. But Cedar and McMahon kind of had the same reaction with total phosphorus and chlorophyll-a. But these readings are taken typically from the deepest part of the lake. With O'Dowd it's still, for the most part, meeting water quality standards.
Motion by Commissioner Pint; Seconded by Commissioner Shea to approve the 2020 Annual Report as written.
The Motion carried unanimously for the Meeting Minutes to be approved as written.
Watercraft Inspection Contract – MBE ▪ For the past two years, we've experimented with hiring a vendor to do watercraft inspections for us on Cedar, McMahon, O’Dowd and Thole. And we've been very pleased with them. They came highly recommended - their name is Waterfront Restorations. But we've decided that it would be a lot easier to do a multiyear contract. Because a multiyear contract was going to be a lot more money, I decided I needed to go out for a request for proposals. There are really only two companies that state that this is one of their main services. I sent an RFP to WaterGuards and to Waterfront Restorations. In that request for proposals there's very specific things that we asked for.
Request for Proposals – 2 companies (WaterGuards ($22/hr) & Waterfront Restorations ($23.94))
WaterGuards did not include 3 things asked for in the RFP:
1.) No monthly reports with invoices 2.) No EOY report with charts/graphs 3.) No statement accepting the terms of the SC contract Waterfront Restorations (WfR) were complete in their responsiveness to the RFP (included everything asked for).
Differences between the two proposals:
WaterGuards – will charge us for DNR training for their inspectors; WfR includes the training in their cost; WaterGuards won’t do an EOY report that is more than one page; WfR does whatever we would like for stats in the EOY report; WaterGuards inspectors not able to ID plants; WfR does train for that; WaterGuards charges extra for any presentation; WfR includes that in their price; WfR gives their inspectors additional training beyond the DNR training and they give me access to GPS based online tracking of the inspectors
The contract will be for 3 years (2021 – 2023) with Waterfront Restorations up to 1400 hours of inspections per year/ contract maximum not to exceed $100,548.
Motion by Commissioner Shea; Seconded by Commissioner Caselius to recommend to the Board the three-year contract with Waterfront restoration.
The Motion carried unanimously to recommend to the Board the three-year contract with Waterfront restoration
BMP Inspection Application Contract – RH We have set up a contract with Wenk, who was recently just acquired by Stantec. They're just two consulting firms that that joined together. The program is intended to track our status review inspections on our Capital Improvement Projects (CIP). It can track other projects as well. But we've essentially set it up just for the all the CIPs that we've been more recently constructing. This application would be a GIS based application - using our current ArcMap license and setting up that application there. There's a number of different things that we have as GIS products, like our story maps, that's a GIS application as well. We've been having some meetings with Wenk along the way, we just did our kickoff meeting last week. We hope to actually have this product done around the July timeframe. What we'll do is we'll enter in all our current CIPs that we have and they'll go into this database. We can pull up this application, when we're in the office on the computer, look up any past inspections. So let's say you are planning on going out to the field. on a certain day, you can go back and look to see what was the status of this project at the last inspection. Was there an area of concern? Did it have some work done on it? Or was it looking good? It would be beneficial for the inspector to know that information, everything's being housed in one spot. So currently, our system is we have some files electronically in our database, SCOOP, and then also their are hardcopy files in the project folders. So there are different spots, this is a way to house them all together. We're setting it up to have kind of two inspections, just a routine inspection and then if we have some maintenance. For the maintenance each inspection, we go out there to log what it is as it is changing. Eventually, you're doing completion of the maintenance activity, and then having those maintenance records in the background as we correct things. That way we can kind of see where things are at.
Motion by Commissioner Caselius; Seconded by Commissioner Thill to recommend approving the status review tracking program.
The Motion carried unanimously to recommend approving the status review tracking program.
Sean O’Malley Streambank Stabilization Amendment – RH ▪ We had reviewed this project late in 2020. So the reason why is back here today is at that time, we did not have very much fun as 2020 was coming to an end, if you remember, we were running very low on our cost share dollars. And we had one grant that this project was eligible for, but all we had was $1,813 and that's what it was approved at. That represented roughly 18% of what the original cost estimate was. So very low. Landowners are eligible for 70% on streambank projects. At that time, the landowner did accept those available funds and it was approved at that point. Due to this project being on Credit River, it's a DNR protected water, there was language in the permit that stipulated when it could be constructed. Originally, it was going to be constructed in the winter. However, the DNR requires these types of projects to be constructed in the summer. This particular landowner reached out and was exploring the idea of amending their current contract. Now that we do have additional dollars for 2021, we can bring cost-share up to what they would’ve been eligible for. But because of our limited funding last year, they just didn't have the opportunity to receive the full amount that they were eligible for. This would be an increase to the contract of $3,202 to bring it to a total of $5,015, which represents half of the project costs. We do have the funds to cover this in our local general fund for 2021. We have a decent amount of funding here with our grants that have become available here more recently. The reason why it is back here is that all streambank stabilizations go through the WPC. They first go to the SWCD for recommendation, which they did recommend approval at their April 20 board meeting. Then the next step would be the WPC recommendation. One thing to note, maybe you did notice this, there is a slight typo on the actual amendment itself. The technical representative has cleaned that up, they got the landowner to sign the revised amendment and I just received it today. With it being such a minor thing. I didn't add it but so the correct one does say $3,202 and the amendment that will be potentially signed if this is approved.
Motion by Commissioner Shea; Seconded by Commissioner Thill approve the additional $3,202 amendment to the application.
The Motion carried unanimously to approve amendment.
Joel and Marge Larsen Shoreline Project Application – RH ▪ Here is another application for your review. As the chair just stated, this is for Joel and Marge Larson, they are on Cedar Lake. What ended up happening with this project is there was a large willow tree on the shoreline that that did come down. What it's doing is undermining the shoreline at the site and it is experiencing erosion. Without the protection of the tree, it is now experiencing some wave action, where it's kind of having that continuous erosion that's occurring. The project is proposing to remove the remaining tree and regrade the bank, install coir logs to stabilize the toe, and then having an upland buffer planted as well. In the end, this project would protect 30 feet along Cedar Lake, from nutrients and sediments from entering the lake. The estimated cost of the project is $3,990. And the proposed amount from the WMO is $2,793. And then the landowners themselves will be kicking in the rest, which is $1,197. This project would come out of the 2021 local general fund, which we do have sufficient funds for the project. This project is a practice that requires a screening committee recommendation. The SWCD did review this at their April 20th board meeting and recommended approval and it is here today for the WPC's action.
Motion by Commissioner Vierling; Seconded by Commissioner Thill to approve Larson shoreline protection application.
The Motion carried unanimously to approve application.
IX. Adjournment
Motion by Commissioner Thill; Seconded by Commissioner Pint to adjourn the meeting at 5:42 PM
The Motion carried unanimously to adjourn
Rita Weaver Date Chair, Watershed Planning Commission
Dominique Archiebald Administrative Assistant
Staff Activities Report May 2021
TECHNICAL ASSISTANCE AND COST SHARE REQUESTS
300 250 200 150 100 50 0 R P R P R P R P R P R P R P R P R P R P R P R P R P M J J A S O N D J F M A M
SWMO PLSLWD LMR & VRW
SOIL HEALTH/COVER CROP INITIATIVE • The SWCD comparison plots with Tim O’Loughlin and Randy Oldenburg were planted • Soil samples and other soil health measurements were taken from the 2 comparison plots and the test plot in Belle Plaine • 4 social media posts were made • Began preparations for a self-guided cover crop tour CLEAN WATER EDUCATION PROGRAM (SCWEP) • Submitted 7 articles to the Scott County SCENE; they included the following topics: CWF funding update; Scott SWCD's 2021 webinar schedule; equipment rental program; cover crop aerial seeding sign up; manure management; SWCD board member profiles; and Lawns to Legumes update • Hosted "How to Build a Raingarden" webinar on April 7; it had 28 attendees • Began preparing classroom lessons on the topic of trees and forests for New Prague 3rd, 4th, and 5th graders • Gathered preferred attendance date and classroom numbers from Outdoor Education Day teachers • Began developing targeted mailings to promote conservation projects eligible under the SWCD’s 2020 CWF grants for the Sand Creek and Spring Lake watersheds. INVENTORY AND ASSESSMENT/PLANNING • Compiling final report for Roberts Sub-Watershed Assessment (SWA) ZONING SUPPORT - COUNTY • Responded to neighbor inquiry regarding Craig Stodola riding arena CUP, including a site visit and correspondence with county staff regarding stockpiling concerns determined unfounded LIVESTOCK OPERATION ASSISTANCE • Researched new MPCA winter manure spreading guidelines and conveyed results to two feedlot owner inquiries; discovered new guidelines only apply to NPDES permitted sites • Provided technical assistance to Meierbachtol Bros re. current feedlot registration status for multiple sites WATER QUALITY, GROUNDWATER AND RAINFALL MONITORING • Surface Water ‒ Conducted two rounds of bi-weekly water quality sampling at Roberts Creek ‒ Conducted two rounds of bi-weekly water quality sampling at Picha Creek ‒ Collected one flow measurement at Picha Creek SWCD Staff Report to WPC May 2021
• Groundwater Observation Wells (DNR) ‒ Participated in working group meeting to discuss Savage Fen wells and future steps • Precipitation (DNR volunteer rainfall monitoring program)
8
6
4 Inches 2
0 A M J J A S O N D J F M A Average (Jordan Field Office, 1980-2015) Latest monthly total
CONSTRUCTION EROSION CONTROL – COUNTY/CREDIT RIVER
300 40 250 30 200 150 20 100 Reviews
Inspections 10 50 0 0 Plan A M J J A S O N D J F M A Permit Development Highway Plan Reviews
WETLAND CONSERVATION ACT - STATE • TEP Meetings & Application Reviews ‒ Steve Schultz Boundary/ Type (New Market Twp) ‒ Railroad culvert repair at CHS Terminal (City of Savage) ‒ Elece Shoquist Boundary/ Type (Spring Lake Twp) ‒ Jamie Boller Boundary/ Type (Spring Lake Twp) ‒ I-35 Utility Extensions No Loss & Boundary/Type (Elko New Market/New Market Twp) ‒ Trongard Development Boundary/Type (City of Savage) ‒ Greenvale Development Boundary/Type (City of Savage) • Notices of Application ‒ Elece Shoquist- Boundary/Type (Spring Lake Twp) • Notices of Decision ‒ Steve Schultz Boundary/Type (New Market Twp) ‒ Andy Simon No Loss (Helena Twp) ‒ John Kimmel No Loss (New Market Twp) ‒ Elece Shoquist Boundary/Type (Spring Lake Twp) ‒ O’Loughlin Ag Replacement (Helena Twp) ‒ Jamie Boller Boundary/Type (Spring Lake Twp) ‒ I-35 Utility Extensions No Loss & Boundary/Type (Elko New Market/New Market Twp) • Enforcement/compliance ‒ No activity
Page 2 of 4
SWCD Staff Report to WPC May 2021
• Helena Wetland Bank ‒ Scheduled monitoring efforts will continue this summer, no major updates at this time BUFFER LAW • Assisted two landowners with seeding/compliance questions TREE PROGRAM • Received 521 orders and distributed 33,400 trees, 122 seed mixes, 70 compost bins and 15 rain barrels; it was a banner year! • Opened website for Native Plant sale to start taking orders May 1 to 21; offering 8 different kits this year CWMA • Working with Steering Committee members and County Ag Inspector to potentially host a summer Noxious Weed Meeting • Will be seeking to hire a contractor(s) for one treatment of Wild Parsnip along targeted roadsides EQUIPMENT RENTAL PROGRAM
2500
2000 Interseeder 1500 John Deere Drill
Acres 1000 Great Plains Drill Brillion Seeder 500
0 2016 2017 2018 2019 2020 2021
Page 3 of 4
TACS PROGRAM ACTION BY SWCD BOARD – MAY ’21 (Includes all projects in the SWMO using SWMO and/or SWCD cost share funds) PAYMENTS
Cooperator Project/ID Action Grant/ID Contract # Amount Efta, David Grassed Waterway/SR-19-178 Partial SWCD 2020 CWF /C20-5633 20-82-SWCD $11,136.00 Gerold, Cody* Conservation Cover/SR-19-051 Final SWMO 2019 LGF 20-83-WMO $1,276.86 Schmidt, Nick* Conservation Cover/SR-19-080 Final SWMO 2020 LGF 20-03-SWMO $5,362.50 Schmidt,Nick* Field Border/SR-19-235 Final SWMO 2020 LGF 20-04-SWMO $3,200.00 Scott County Parks* Water & Sediment Basin/SR-20-065 Final SWCD 2017 CWF LMR/C17-1253 20-62-SWCD $3,939.30 SWCD 2017 CWF LMR/C17-1253 20-115-SWCD $6,500.00 Scott County Parks* Grassed Waterway/SR-20-100 Final SWMO 2019 WBF/P19-3277 20-61-SWMO $2,452.30 Wick, Placidus* Grassed Waterway/SR-17-230 Final SMWO 2018 LGF WMO 18-50 $25,269.38 $59,136.34 NEW APPLICATIONS
Cooperator Project/ID Action Grant/ID Contract # Amount
Borchardt Family Farms, LLC* Field Border/SR-20-231 Approval SWMO 2021 LGF 21-044-SWMO $8,700 Casey Acres Inc. Whole Farm Planning/SR-20-226 Approval SWMO 2021 LGF 21-038-SWMO $1,000 Hennen, Luke Raingarden/SR-21-075 Approval SWMO 2021 LGF 21-048-SWMO $250 Jasnoch, Karin Raingarden/SR-20-119 Approval SWMO 2021 LGF 21-047-SWMO $250 Jirik, Jennifer Raingarden/SR-21-049 Approval SWMO 2021 LGF 21-051-SWMO $500 Koepp, Kevin* Grade Stabilization Structure/SR-19-159 SC Rec* SWMO 2021 LGF 21-041-SWMO $12,936 Schmidt, Chris Conservation Cover/SR-21-035 Approval SWMO 2021 LGF 21-045-SWMO $750 Schmitz, Lowell & Brenda* Filter Strip/SR-21-036 Approval SWMO 2021 LGF 21-047-SWMO $2,250 Simon, Andy Conservation Cover/SR-21-034 Approval SWMO 2021 LGF 21-039-SWMO $2,000 Wick, Vernon Residue Mgmt/SR-21-025 Approval SWMO 2021 LGF 21-046-SWMO $3,000 *Project Fact Sheets attached $31,636.00 AMENDMENTS Cooperator Project/ID Action Grant/ID Contract # Amount Efta, David Cropland Grassed Waterway/SR-19-178 Approval SWCD 2020 CWF/C20-5633 20—82-SWCD $3,536
Page 4 of 4
Cody Gerold Conservation Cover
Cooperator & Location Before Name Cody Gerold Address 14600 Blakeley Tr City/Twp Blakeley Watershed SWMO
Project Details Practice Conservation Cover Quantity 3.00 Acres Project ID SR-19-051 Project Term 10 year(s) Resource Protected DNR Stream/MN River/Top of Bluff
Description Cody wanted to protect the edge of his crop field from soil After erosion by restoring it to a perennial native cover once characteristic of southern and western Minnesota. This practice improves water quality by eliminating sources of sediment and other pollutants and reducing runoff volumes. Cody's native seed mix included numerous grasses and flowers, which in addition to providing water quality benefits will provide essential wildlife and pollinator habitat and beautify Scott County's natural landscape.
Total Cost Sources Cooperator: $705.00 SWMO: $1,276.86 $9,450.58 SWCD: $7,468.72
Federal: $0.00
Environmental Benefits Unit Costs* Local Funding Partner Parameter Before After Saved Sed Phos Runoff Soil Erosion (tons/yr) 58.8 0.0 58.8 $/Ton $/Pound $/Ac Ft Sediment (tons/yr) 17.90 0.00 17.90 SWCD: $41.72 $37.34 $497.91 Phosphorus (lbs/yr) 20.00 0.00 20.00 SWMO: $7.13 $6.38 $85.12 Runoff Volume (acre ft) 2.50 1.00 1.50 Overall: $52.80 $47.25 $630.04
*Over term of cost share contract
For more information contact Scott SWCD at 952.492.5425 or visit scottswcd.org
Nick Schmidt Conservation Cover
Cooperator & Location Before Name Nick Schmidt Address 1129 Farmers Lane City/Twp Blakeley Watershed SWMO
Project Details Practice Conservation Cover Quantity 3.90 Acres Project ID SR-19-080 Project Term 10 year(s) Resource Protected MN River
Description Nick Schmidt restored 3.9 acres of existing cropland to a After native prairie ecosystem once characteristic of Minnesota. This project will improve water quality by eliminating sources of sediment and other pollutants and reduced runoff volumes. The prairie seed mix included numerous native grasses and flowers, which in addition to providing water quality benefits will provide essential wildlife and pollinator habitat and beautify Scott County's natural landscape.
Total Cost Sources Cooperator: $1,250.00 SWMO: $7,625.00 $12,996.50 SWCD: $4,121.50
Federal: $0.00
Environmental Benefits Unit Costs* Local Funding Partner Parameter Before After Saved Sed Phos Runoff Soil Erosion (tons/yr) 19.0 0.0 19.0 $/Ton $/Pound $/Ac Ft Sediment (tons/yr) 4.40 0.00 4.40 SWCD: $93.67 $60.61 $242.44 Phosphorus (lbs/yr) 6.80 0.00 6.80 SWMO: $173.30 $112.13 $448.53 Runoff Volume (acre ft) 3.10 1.40 1.70 Overall: $295.38 $191.13 $764.50
*Over term of cost share contract
For more information contact Scott SWCD at 952.492.5425 or visit scottswcd.org
Nick Schmidt Field Border
Cooperator & Location Before Name Nick Schmidt Address 1129 Farmers Lane City/Twp Blakeley Watershed SWMO
Project Details Practice Field Border Quantity 2.40 Acres Project ID SR-19-235 Project Term 10 year(s) Resource Protected Minnesota River
Description Nick Schmidt wanted to reduce sheet/rill erosion by installing After a sensitive field border. Doing so removed the need for headlands on his crop field and allowed for row cropping on the contour. The sensitive field border complemented an area that was prone to ephemeral erosion that the landowner addressed on his own.
Total Cost Sources Cooperator: $0.00 SWMO: $6,400.00 $6,400.00 SWCD: $0.00
Federal: $0.00
Environmental Benefits Unit Costs* Local Funding Partner Parameter Before After Saved Sed Phos Runoff Soil Erosion (tons/yr) 7.2 0.0 7.2 $/Ton $/Pound $/Ac Ft Sediment (tons/yr) 1.50 0.00 1.50 SWCD: $0.00 $0.00 $0.00 Phosphorus (lbs/yr) 2.70 0.00 2.70 SWMO: $426.67 $237.04 $914.29 Runoff Volume (acre ft) 2.00 1.30 0.70 Overall: $426.67 $237.04 $914.29
*Over term of cost share contract
For more information contact Scott SWCD at 952.492.5425 or visit scottswcd.org
Scott County Parks Dept Water and Sediment Control Basin
Cooperator & Location Before Name Scott County Parks Dept Address 200 Fourth Ave W. City/Twp Blakeley Watershed SWMO
Project Details Practice Water and Sediment Control Basin Quantity 1.00 Each Project ID SR-20-065 Project Term 10 year(s) Resource Protected Intermittent Trib. to MN River
Description Scott County Parks was experiencing a couple ephemeral After gullies on there Blakeley Bluffs Future Park Reserve property. Sediment, nutrients, and other pollutants from these eroding areas flow unimpeded to the Minnesota River via a steep ravine channel. A water and sediment control basin (WASCOB) was installed with a diversion to intercept surface runoff and eliminate the gully erosion. In addition, the WASCOB will reduce peak discharge from a 10-year storm event from 5 cfs to .28 cfs, which helps alleviate erosion within the below ravine channel as well.
Total Cost Sources Cooperator: $460.00 SWMO: $0.00 $4,600.00 SWCD: $4,140.00
Federal: $0.00
Environmental Benefits Unit Costs* Local Funding Partner* Parameter Before After Saved Sed Phos Runoff Soil Erosion (tons/yr) 29.2 0.0 29.2 $/Ton $/Pound $/Ac Ft Sediment (tons/yr) 29.24 0.00 29.24 SWCD: $14.16 $14.16 $0.00 Phosphorus (lbs/yr) 29.24 0.00 29.24 SWMO: $0.00 $0.00 $0.00 Runoff Volume (acre ft) 0.00 0.00 0.00 Overall: $15.73 $15.73 $0.00
*Over term of cost share contract * The SWMO provided support for SWCD Technical Assistance
For more information contact Scott SWCD at 952.492.5425 or visit scottswcd.org
Scott County Parks Dept Grassed Waterway
Cooperator & Location Before Name Scott County Parks Dept Address 200 Fourth Ave W. City/Twp Blakeley Watershed SWMO
Project Details Practice Grassed Waterway Quantity 862.00 Lin Ft Project ID SR-20-100 Project Term 10 year(s) Resource Protected Intermittent Trib. to MN River
Description This site was experiencing an eroding ephemeral gully that After was being exacerbated by persistent flows coming from a wetland at field edge. A grass waterway having a flat graded section and berm to maximize infiltration and evapotranspiration in its upper reach was constructed according to specifications. Willow live stakes will be planted in this area (station 0+00 to 0+25) in Spring of 2021; this was not required per design standards, but is being prescribed to help disperse outflow from the wetland and promote infiltration.
Total Cost Sources Cooperator: $1,010.00 SWMO: $2,590.00 $10,100.00 SWCD: $6,500.00
Federal: $0.00
Environmental Benefits Unit Costs* Local Funding Partner Parameter Before After Saved Sed Phos Runoff Soil Erosion (tons/yr) 72.5 0.0 72.5 $/Ton $/Pound $/Ac Ft Sediment (tons/yr) 36.25 0.00 36.25 SWCD: $17.93 $17.93 $0.00 Phosphorus (lbs/yr) 36.25 0.00 36.25 SWMO: $7.14 $7.14 $0.00 Runoff Volume (acre ft) 0.00 0.00 0.00 Overall: $27.86 $27.86 $0.00
*Over term of cost share contract
For more information contact Scott SWCD at 952.492.5425 or visit scottswcd.org
Borchardt Family Farms, LLC Field Border
Cooperator & Location Map of Project Site Name Borchardt Family Farms, LLC Address 21251 Panama Avenue City/Twp Spring Lake Watershed SWMO
Project Details Practice Field Border Quantity 5.80 Acres Project ID SR-20-231 Project Term 10 year(s) Resource Protected Unnamed Public Water Wetland
Overview The renter (Rob Casey) would like to reduce sheet/rill erosion by installing a sensitive field border. Doing so will remove the need for headlands on steep parts of the field. The sensitive Current Project Site field border will complement existing grassed waterways in the field.
Total Cost Sources Cooperator: $0.00 SWMO: $8,700.00 $8,700.00 SWCD: $0.00
Federal: $0.00
Environmental Benefits Unit Costs* Local Funding Partner Parameter Before After Saved Sed Phos Runoff Soil Erosion (tons/yr) 62.5 55.6 6.9 $/Ton $/Pound $/Ac Ft Sediment (tons/yr) 24.10 7.51 16.59 SWCD: $0.00 $0.00 $0.00 Phosphorus (lbs/yr) 34.49 12.77 21.72 SWMO: $52.44 $40.06 $533.74 Runoff Volume (acre ft) 4.74 3.11 1.63 Overall: $52.44 $40.06 $533.74
*Over term of cost share contract
For more information contact Scott SWCD at 952.492.5425 or visit scottswcd.org
Kevin Koepp Grade Stabilization Structure
Cooperator & Location Map of Project Site Name Kevin Koepp Address 817 Farmers Way City/Twp Blakeley Watershed SWMO
Project Details Practice Grade Stabilization Structure Quantity 1.00 Each Project ID SR-19-159 Project Term 10 year(s) Resource Protected Intermittent Stream
Overview
Landowner Kevin Koepp has taken steps to reduce soil erosion entering the ravines on his rented property by installing filter Current Project Site strips and maintaining an existing Grade Stabilization Structure (GSS constructed in 1966). The GSS is failing due to corrosion of the pipe. Water has started to undermine the soil under the pipe and is causing slumping of the earthern berm. Landowner has tried to fix what he can but we are in agreement the structure will continue to fail and eventually cause both erosion of the GSS berm and erosion head-cutting within the ravine. A new GSS was designed based on current NRCS specs and is similar to the 1966 GSS.
Total Cost Sources Cooperator: $8,624.00 SWMO: $12,936.00 $21,560.00 SWCD: $0.00
Federal: $0.00
Environmental Benefits Unit Costs* Local Funding Partner Parameter Before After Saved Sed Phos Runoff Soil Erosion (tons/yr) 13.7 0.0 13.7 $/Ton $/Pound $/Ac Ft Sediment (tons/yr) 13.70 0.00 13.70 SWCD: $0.00 $0.00 $0.00 Phosphorus (lbs/yr) 13.70 0.00 13.70 SWMO: $94.42 $94.42 $0.00 Runoff Volume (acre ft) 0.00 Overall: $157.37 $157.37 $0.00
*Over term of cost share contract
For more information contact Scott SWCD at 952.492.5425 or visit scottswcd.org
Lowell & Brenda Schmitz Filter Strip
Cooperator & Location Map of Project Site Name Lowell & Brenda Schmitz Address 24415 Delaware Ave City/Twp Belle Plaine Watershed SWMO
Project Details Practice Filter Strip Quantity 0.50 Acres Project ID SR-21-036 Project Term 15 year(s) Resource Protected Restored Wetland
Overview Lowell's wetland was enrolled into the wetland restoration program as a joint practice with Ray Soller's wetland Current Project Site restoration project. He was not required to add a 30ft. buffer to his wetland, but he would like to install a 30ft filter strip to protect the wetland.
Total Cost Sources Cooperator: $0.00 SWMO: $2,250.00
$2,250.00 SWCD: $0.00
Federal: $0.00
Environmental Benefits Unit Costs* Local Funding Partner Parameter Before After Saved Sed Phos Runoff Soil Erosion (tons/yr) 0.8 0.0 0.8 $/Ton $/Pound $/Ac Ft Sediment (tons/yr) 4.27 1.33 2.94 SWCD: $0.00 $0.00 $0.00 Phosphorus (lbs/yr) 7.21 2.80 4.41 SWMO: $51.02 $34.01 $0.00 Runoff Volume (acre ft) 0.00 0.00 0.00 Overall: $51.02 $34.01 $0.00
*Over term of cost share contract
For more information contact Scott SWCD at 952.492.5425 or visit scottswcd.org
Placidus Wick Grassed Waterway
Cooperator & Location Before Name Placidus Wick Address 19950 Pueblo Ave City/Twp Sand Creek Watershed SWMO
Project Details Practice Grassed Waterway Quantity 2,325.00 Lin Ft Project ID SR-17-230 Project Term 10 year(s) Resource Protected Tributary to Sand Creek
Description A grassed waterway is a shaped or graded channel that is established with suitable vegetation to convey runoff from terraces, diversions, or other water concentrations at non- After erosive velocities to a stable outlet. This practice is used to repair or prevent ephemeral (seasonal) or continual gully erosion, and to protect water quality. Placidus has experienced erosion for several years and decided to fix the erosion with a system of grassed waterways and diversions.
Total Cost Sources Cooperator: $3,394.00 SWMO: $30,546.00
$33,940.00 SWCD: $0.00
Federal: $0.00
Environmental Benefits Unit Costs* Local Funding Partner Parameter Before After Saved Sed Phos Runoff Soil Erosion (tons/yr) 163.6 0.0 163.6 $/Ton $/Pound $/Ac Ft Sediment (tons/yr) 36.80 0.00 36.80 SWCD: $0.00 $0.00 $0.00 Phosphorus (lbs/yr) 36.80 0.00 36.80 SWMO: $83.01 $83.01 $0.00 Runoff Volume (acre ft) - - - Overall: $92.23 $92.23 $0.00
*Over term of cost share contract
For more information contact Scott SWCD at 952.492.5425 or visit scottswcd.org Scott Watershed Management Organization 200 Fourth Avenue West Shakopee, MN 55379-1220 952-496-8054 Fax 952-496-8496 www.scottcountymn.gov/wmo
Memorandum
May 19, 2021
To: Watershed Planning Commission
From: Melissa Bokman, Sr. Water Resources Planner
Subject: Wake Boats
This memo is in response to a request for more information about wake boats and their impacts to lakes to understand how to address the concerns of our lake residents and protect the future water quality of Scott County lakes.
Wakeboard boats, are specially designed to create a large specially shaped wake which wakeboarders can surf and jump the wakes without a tow rope. Most wake boats are motorized boats with a power of more than 350 hp.
Current Study Currently the University of Minnesota St. Anthony Falls Laboratory is just starting a multi-year study to investigate the affects of wake boats on area lakes in Minnesota. The study will investigate the wake and how that wake moves toward the shoreline and starts to interact with the bottom of the lake and how it impacts the shoreline. The study started in late summer 2020 and is expected to take three to four years.
Past Studies According to a study done by University of Quebec at Montreal (UQAM), analyzed the variations in turbulent kinetic energy (TKE) and resuspension of sediments caused by wakeboat waves upon their arrival at the shore, by varying the type of wakeboat movement, and distance from the shore to which it is situated, and the slope of these shores (cite). The main results of that research are: • All wakeboats passages induce a significant increase in the energy contained in the waves that reach the shore, on average by a factor of 4. • The impact of wakeboat passes is directly and inversely related to the distance between the passage and the shore. • Of the three different types of waves produced by a wakeboat, the waves of wakesurf are the ones that cause the greatest impact when they arrive at the shore (1.7 times higher than the waves of a boat in normal displacement).
• Wakeboat passes have a greater impact on shorelines with steeper slopes than those with gentle slopes. • Data shows that the energy produced by the wakeboat dissipates completely before reaching the banks (and therefore have no significant effect) when the wakeboat passes are 300m or more from the shore.
Another study completed by Laval University in Quebec City, Canada, was completed to assess the impact in the water column by wake boats. The technology and methodology in this study were used to answer the questions that relate to depth of the impact and the velocity generated in the water column. Results of that study conclude that: • Wake boats and wake surfing impact the water column up to 16 feet in depth at a speed of 12 mph; • Under the conditions studied, wake surf/ wake board has the potential to impact the water column and remobilize bottom sediments up to 16 feet (5 meters) for more than a minute;
The concerns with this type of water column disturbance are an increase in water turbidity or clarity, total phosphorus and orthophosphorus concentration, and dissolved oxygen near the bottom of the lake. An increase in total phosphorus in the water column can promote the development of algae and blue green algae blooms.
Studies are attached.
Other Organization Restrictions I spoke with Ryan Pinkalla, Water Resources Technician, City of Chanhassen regarding a similar situation on Lake Lotus. After a year-long process of public meetings with lake user groups for and opposed to possible restrictions of wake boats on some lakes in the City of Chanhassen, the city decided to update their ordinance and created No Wake ordinances on a few lakes to address the issue of impacts from wake boats rather than restrict a particular user group. The decision to do this was also due to the fact that there isn’t sufficient data in Minnesota on the impacts of wake boats. No Wake restrictions were established at a trigger elevation of the Ordinary High-Water Level (OHW) and 100 Year Flood Elevation depending on the lake.
I contact Lt. Adam Block from the DNR, he stated the only submission they have received for restrictions on wake boats was last summer in Stearns County. They denied the restrictions at that time because they and the Legislature are waiting for the study being done by the U of M St. Anthony Falls Laboratory on wave energy of wake boats. They don’t want to approve anything that might go against what that study might conclude.
Current Legislation There is currently a House Bill at the MN Legislature HR1606 (attached) which had its first reading in the House on February 25, 2021. The companion Bill at the Senate SF 1639 (attached) had its first reading on March 1, 2021. Both bills have been referred to the Environment and Natural Resources Finance and Policy committee.
Tracking additional data The SWMO already participates in the Citizen-Assisted Lake Monitoring Program (CAMP) with volunteers taking lake samples bi-weekly for total phosphorus, chlorophyll-a and secchi. We track trends in water quality on the lake annually by including that data in our Annual Report to BWSR.
Options for additional data to track impacts from wake boats are: 1.) Ask CAMP volunteers to take additional secchi readings when they are on the lake. Record observations (ie. wake boats present); 2.) Work with willing lake association volunteers to be aware and observe when they see wake boats on the lake and keep a journal of observations (churning of bottom sediments, disturbance to other boaters, wakes crashing into shorelines); 3.) Track the number and frequency of wake boats on the lakes we contract for watercraft inspections to understand how often those boats are on Scott County lakes. Most inspections are scheduled for Friday through Sunday. 4.) Pin shorelines with rebar to measure erosion. Whether proving the erosion came from wake boats specifically versus other watercraft or other variables such as lack of deep- rooted vegetation, may be difficult.
01/06/21 REVISOR CKM/LN 21-01123
This Document can be made available in alternative formats upon request State of Minnesota HOUSE OF REPRESENTATIVES NINETY-SECOND SESSION H. F. No. 1606 02/25/2021 Authored by Koegel and Stephenson The bill was read for the first time and referred to the Committee on Environment and Natural Resources Finance and Policy
1.1 A bill for an act
1.2 relating to natural resources; regulating wake surfing on waters of this state; 1.3 amending Minnesota Statutes 2020, sections 86B.005, by adding subdivisions; 1.4 86B.315, subdivisions 1, 2, by adding subdivisions.
1.5 BE IT ENACTED BY THE LEGISLATURE OF THE STATE OF MINNESOTA:
1.6 Section 1. Minnesota Statutes 2020, section 86B.005, is amended by adding a subdivision
1.7 to read:
1.8 Subd. 17a. Wake surfer. "Wake surfer" means a person who wake surfs.
1.9 Sec. 2. Minnesota Statutes 2020, section 86B.005, is amended by adding a subdivision to
1.10 read:
1.11 Subd. 17b. Wake surf. "Wake surf" means:
1.12 (1) to surf a wake, regardless of whether the surfer is being pulled by a tow rope attached
1.13 to the watercraft that is producing the wake; or
1.14 (2) to operate a boat that creates a wake that is, or is intended to be, surfed by another
1.15 person.
1.16 Sec. 3. Minnesota Statutes 2020, section 86B.315, subdivision 1, is amended to read:
1.17 Subdivision 1. Observer or mirror required. A person may not wake surf on waters
1.18 of this state or operate a watercraft on waters of this state and create a wake for a wake
1.19 surfer or tow while towing a person on water skis, an aquaplane, a surfboard, a saucer, or
1.20 a similar device unless:
Sec. 3. 1 01/06/21 REVISOR CKM/LN 21-01123
2.1 (1) there is another person in the watercraft in addition to the operator who is in a position
2.2 to continually observe the person being towed; or
2.3 (2) the boat is equipped with a mirror providing the operator a wide field of vision to
2.4 the rear.
2.5 Sec. 4. Minnesota Statutes 2020, section 86B.315, subdivision 2, is amended to read:
2.6 Subd. 2. Prohibited night activities. (a) On waters of this state, from one-half hour
2.7 after sunset to sunrise of the following day, a person may not:
2.8 (1) wake surf;
2.9 (2) operate a watercraft creating a wake for a wake surfer;
2.10 (3) be towed by a watercraft; or
2.11 (4) operate a watercraft towing a person on water skis, an aquaplane, a surfboard, a
2.12 saucer, or another device.
2.13 (b) On waters of this state, a person may not wake surf on:
2.14 (1) a lake or bay of 50 acres or less; or
2.15 (2) a waterway where the waterway is less than 500 feet wide.
2.16 (c) On waters of this state, a person may not wake surf at greater than slow-no wake
2.17 speed within 200 feet of a:
2.18 (1) shoreline;
2.19 (2) dock;
2.20 (3) swimmer;
2.21 (4) raft used for swimming or diving; or
2.22 (5) moored, anchored, or nonmotorized watercraft.
2.23 Sec. 5. Minnesota Statutes 2020, section 86B.315, is amended by adding a subdivision to
2.24 read:
2.25 Subd. 3. Requirements for wake surf watercraft. A person may not wake surf unless
2.26 the watercraft used to wake surf is powered with a propeller that is forward of the watercraft's
2.27 transom or swim platform or powered by a jet drive.
Sec. 5. 2 01/06/21 REVISOR CKM/LN 21-01123
3.1 Sec. 6. Minnesota Statutes 2020, section 86B.315, is amended by adding a subdivision to
3.2 read:
3.3 Subd. 4. No preemption. Nothing in this section shall be construed to prevent a local
3.4 government from regulating wake surfing more than 200 feet from shore in accordance with
3.5 this chapter.
Sec. 6. 3 01/06/21 REVISOR CKM/LN 21-01123 as introduced SENATE STATE OF MINNESOTA NINETY-SECOND SESSION S.F. No. 1639
(SENATE AUTHORS: JOHNSON) DATE D-PG OFFICIAL STATUS 03/01/2021 620 Introduction and first reading Referred to Environment and Natural Resources Policy and Legacy Finance
1.1 A bill for an act
1.2 relating to natural resources; regulating wake surfing on waters of this state; 1.3 amending Minnesota Statutes 2020, sections 86B.005, by adding subdivisions; 1.4 86B.315, subdivisions 1, 2, by adding subdivisions.
1.5 BE IT ENACTED BY THE LEGISLATURE OF THE STATE OF MINNESOTA:
1.6 Section 1. Minnesota Statutes 2020, section 86B.005, is amended by adding a subdivision
1.7 to read:
1.8 Subd. 17a. Wake surfer. "Wake surfer" means a person who wake surfs.
1.9 Sec. 2. Minnesota Statutes 2020, section 86B.005, is amended by adding a subdivision to
1.10 read:
1.11 Subd. 17b. Wake surf. "Wake surf" means:
1.12 (1) to surf a wake, regardless of whether the surfer is being pulled by a tow rope attached
1.13 to the watercraft that is producing the wake; or
1.14 (2) to operate a boat that creates a wake that is, or is intended to be, surfed by another
1.15 person.
1.16 Sec. 3. Minnesota Statutes 2020, section 86B.315, subdivision 1, is amended to read:
1.17 Subdivision 1. Observer or mirror required. A person may not wake surf on waters
1.18 of this state or operate a watercraft on waters of this state and create a wake for a wake
1.19 surfer or tow while towing a person on water skis, an aquaplane, a surfboard, a saucer, or
1.20 a similar device unless:
Sec. 3. 1 01/06/21 REVISOR CKM/LN 21-01123 as introduced
2.1 (1) there is another person in the watercraft in addition to the operator who is in a position
2.2 to continually observe the person being towed; or
2.3 (2) the boat is equipped with a mirror providing the operator a wide field of vision to
2.4 the rear.
2.5 Sec. 4. Minnesota Statutes 2020, section 86B.315, subdivision 2, is amended to read:
2.6 Subd. 2. Prohibited night activities. (a) On waters of this state, from one-half hour
2.7 after sunset to sunrise of the following day, a person may not:
2.8 (1) wake surf;
2.9 (2) operate a watercraft creating a wake for a wake surfer;
2.10 (3) be towed by a watercraft; or
2.11 (4) operate a watercraft towing a person on water skis, an aquaplane, a surfboard, a
2.12 saucer, or another device.
2.13 (b) On waters of this state, a person may not wake surf on:
2.14 (1) a lake or bay of 50 acres or less; or
2.15 (2) a waterway where the waterway is less than 500 feet wide.
2.16 (c) On waters of this state, a person may not wake surf at greater than slow-no wake
2.17 speed within 200 feet of a:
2.18 (1) shoreline;
2.19 (2) dock;
2.20 (3) swimmer;
2.21 (4) raft used for swimming or diving; or
2.22 (5) moored, anchored, or nonmotorized watercraft.
2.23 Sec. 5. Minnesota Statutes 2020, section 86B.315, is amended by adding a subdivision to
2.24 read:
2.25 Subd. 3. Requirements for wake surf watercraft. A person may not wake surf unless
2.26 the watercraft used to wake surf is powered with a propeller that is forward of the watercraft's
2.27 transom or swim platform or powered by a jet drive.
Sec. 5. 2 01/06/21 REVISOR CKM/LN 21-01123 as introduced
3.1 Sec. 6. Minnesota Statutes 2020, section 86B.315, is amended by adding a subdivision to
3.2 read:
3.3 Subd. 4. No preemption. Nothing in this section shall be construed to prevent a local
3.4 government from regulating wake surfing more than 200 feet from shore in accordance with
3.5 this chapter.
Sec. 6. 3 Project evaluation of the impact of the waves created by the type of boats wakeboat on the shore of Lake Memphremagog and Lovering
Sara Mercier-Blais and Yves Prairie
2014 J une
Management Committee Yves Prairie, professor in the Department of Biological Sciences at UQAM, responsible for research Lucie Borne, Lac Lovering Conservation Society Robert Benoit, Memphremagog Conservation Inc. Sara Mercier-Blais, Master's student in Biological Sciences at UQAM Claire Vanier, Community Service at UQAM
Writing Sra Mercier-Blais Yves Prairie
Revision and coordination of production Claire Vanier
Financial support Research and Creation Financial Assistance Program, UQAM - Research in Community Services, Component 2 Lake Lovering Conservation Society Memphremagog Conservation Inc.
Lake Lovering Community service at the Memphremagog Conservation Université du Québec à Conservation Inc. Montréal Society PO Box 8888, PO Box 447, PO Stn.Downtown, Magog, Qc Box 70,Magog, Montreal (Qc) J1X 3W7 Qc J1X 3W7 H3C 3P8 Phone: (514) 987-3177 (819) 868-2669 (819)340-8721 www.sac.uqam.ca/accueil.asp www.memphremagog.org/fr/ind www.laclovering.org/ x ex.php
EXECUTIVE SUMMARY
The presence of wakeboat type boats has been intensifying over the last few years on Quebec's waterways. More and more lakeside residents are concerned about the potential impact of such boats on lakeshore, including resuspension of sediments caused by increased energy in these waves. .
The objective of this research was to develop a scientific framework to validate the existence, magnitude and modalities of the impacts of oversize waves generated by wakeboats on the lake environment in Quebec. The research was conducted at Lakes Lovering and Memphremagog, in collaboration with SCLL and MCI, and with the support of Community Services.
The main results of the research are as follows:
All wakeboats passages induce a significant increase in the energy contained in the waves that reach the shore, on average by a factor of 4. The impact of wakeboat passes is directly and inversely related to the distance between the passage and the shore. Of the three different types of waves produced by a wakeboat, the waves of wakesurf are the ones that cause the greatest impact when they arrive at the shore (1.7 times higher than the waves of a boat in normal displacement). Wakeboat passes have a greater impact on shorelines with steeper slopes than those with gentle slopes . Our data shows that the energy produced by the wakeboat dissipates completely before reaching the banks (and therefore have no significant effect) when the wakeboat passes are 300 m or more from the shore.
TABLE OF CONTENTS
Executive Summary i List of tables iii List of figures iii Introduction 1 Methodology 3 Sampling Plan 3 Wakeboat trip types 3 Choice and characterization of sites - type of shoreline 4 Sampling 5 Resuspension of sediments 5 Turbulent kinetic energy 5 Assessment of normal conditions 6 Laboratory analysis 6 Statistical analyzes 7 Limitations of the study 7 Results and discussion 8 Turbulent kinetic energy (TKE) 9 Resuspension of sediments 11 Distance from the bank 14 Impact of shoreline slope on energy reaching the shoreline 16 Characteristics of the waves 18 Conclusion 20 Bibliography 21 Attachments 22
Appendix 1. Sampling sites in Lovering Lake and Lake Memphremagog ……………. 22 Appendix 2. Nautical Regulations Map of Lovering Lake …………………………..... 23 Appendix 3. Maps of the Lake Memphremagog nautical regulation …………………. 24 Appendix 3. Raw Data Tables of Physical Parameters ...... 25 Appendix 4. Tables of Raw Data for Suspended Sediment Values……………….………. 31
LIST OF TABLES
Table 1. Characteristics of sampled sites………………………………………………………………. 4
Table 2. Comparisons of results under normal conditions and during the passage of a wakeboat: speeds (average, maximum, minimum); turbulent kinetic energy (TKE), energy horizontal (ε x ) and vertical (ε z ); suspended sediment …………………… 8
Table 3. Average wave train duration (sec), number of waves per wave train length and maximum speed (ms -1 ) at different shore distances (100, 150, 200 m) and the type of displacement of the wakeboat ...... 9
LIST OF FIGURES
Figure 1. Sampling plan for measuring three different types of trip to three shoreline distances and six sampling sites ...... 3
Figure 2. Illustration of the calculation of coastal slopes of sampling sites ...... 4
Figure 3. Example representing the speed (ms -1 ) of the dimensions x (red), y (green) and z (blue) for a period of normal waves, and when passing the boat wave ( wave train ) ...... 5
Figure 4. Example of power spectrum for the calculation of the energy dissipation ...... 6
Figure 5. The energy (TKE) is in the normal waves (dark gray) and that present in the wave following the passage of a wakeboat 100, 150 and 200 m from the shore, and the type of boat passage (a: all types of passage; b: 10 miles / h; c: 20 miles / hr; d : 30miles / h) ...... 9
Figure 6. The additional energy induced by the passage of a wakeboat (TKE wave - normal TKE) depending on the type of passage (10, 20 and 30 mph) and the distance to the shore (a: 100 m; b: 150 m; c: 200m) and that induced according to the distance to the bank (100, 150 and 200 m) and according to the type of crossing (d: 10 miles / h; e: 20 miles / h; f: 30 miles / h) ……………………. 10
Figure 7. Resuspension of sediments caused by normal waves (dark gray) and caused by waves following the passage of a wakeboat at 100, 150 and 200 m depending on the type of passage (a: all types of passage, b: 10 miles / h, c: 20 miles / h, d: 30 miles / h) ...... 12
Figure 8. The resuspension of additional sediments induced according to the type of passage (10, 20 and 30 miles / h) and the passage distance (a: 100 m, b: 150 m, c: 200 m) and that induced according to the distance of the bank (100, 150 and 200 m) and according to the type of passage (d: 10 miles / h; e: 20 miles / h; f: 30 miles / h;) ...... 13
Figure 9. Linear regression of a) energy (TKE) and b) suspended sediment, as a function of the distance from shore to Lakes Lovering (light gray) and Memphrémagog (black) ...... 14
Figure 10. Map of the navigable area by wakeboats (dark gray) following regulation limiting their activity to more than 300 m from Lakes Memphrémagog (a) and Lovering (b) ...... 16
Figure 11. Energy (TKE) reaching the shoreline at sites with steep coastal slope (dark gray) or soft (pale gray) for normal waves (a) and wakeboard (b) ……… 17
Figure 12. Linear Regression Between Energy (TKE) and Shoreline Slope: a) Under Normal Conditions and (b) during the passage of a wakeboat wave train for 5 sampled sites ...... 18
INTRODUCTION
In recent years, new aquatic sports have emerged in Québec's water bodies. In particular, the popularity of wakeboats is constantly increasing in many lakes, including Memphrémagog and Lovering Lakes. Located north of the Appalachian region, these two lakes are important recreational and tourist centers for both residents and vacationers. The configuration of the wakeboats can create a wave high enough to allow the followers to "surf" at the back of the boat, either on a wakesurf or on a wakeboard. While doing wakesurfing, the surfer is not attached to the boat, but he surfs behind the wake of it on a board very similar to a normal surfboard. In the case of wakeboarding, the person surfs behind the boat, staying attached to it at all times, on a board much closer to a snowboard with slippers.
With the exception of some works, such as those of Hill, Beachler and Johnson (2002), limited to the Chilkat River in Alaska, and those of Péloquin-Guay (Memorial, U. of Montreal, 2013) on the Batiscan River, very few Experimental studies have been conducted to rigorously and quantitatively assess the potential of the boats to accelerate bank erosion, and none have been carried out specifically on wakeboat type boats in lakes. Shoreline erosion can be an important nutrient carrier to lakes, particularly in deforested areas bordering them (Keenan and Kimmins 1993). To date, no regulations govern the use of these boats in relation to their environmental impact. Indeed, the only regulation currently in force is that related to boating safety, which limits the speed to 10 km / h (6.2 mi/hr.) when the boat moves within 100 m of the shore. In the rest of the lake, the speed limit is 70 km / h (43.5 mi/hr} (Appendices 2 and 3: Maps of the nautical regulations of the Government of Quebec, MRC Memphremagog 2011, MRC Memphremagog 2013).
Each wave created by a boat, or by the wind, contains a certain amount of energy (turbulent kinetic energy, TKE). Some of this energy will be dissipated quickly but a certain amount will be able to reach the banks. It is this additional energy that can contribute to accelerated bank erosion and re-suspension of existing sediments. So far, no relationship has been developed to allow the quantitative comparison between the energy induced by the ships.
The objective of this project was to develop a scientific framework to validate the existence, extent and modalities of wave impacts caused by wakeboats on the lake environment in Quebec, based on measurements made at lakes Lovering and Memphremagog. Three sites in each lake were alternately instrumented, to acquire the physical data allowing to quantify the energy induced by the wakeboat wave train that reaches the banks. In addition, measures have been taken to evaluate the resuspension of sediments. Sampling plan
METHODOLOGY
To properly quantify the effect of wakeboats on the energy received by the banks, we chose to proceed with a controlled experimental plan, that is to say where we can impose specific configurations and trajectories to the boat. Our protocol measures the energy generated by waves of wakeboats according to several combinations of three main factors:
1) the type of displacement of the boat, characterized by the speed of the boat, and thus the type of waves created; 2) the distance from the shore to which the boat passes (100, 150 and 200 m); 3) the type of shore, following the slope of the shore.
Figure 1 illustrates this sample design. For each combination, measurements were taken twice to assess the variability between trials of the same configuration.
Figure 1. Sampling plan for measuring three different types of displacement at three shoreline distances and at six sampling sites
Wakeboat trip types Moving a boat can create different types of waves. In this research, three types of waves were studied: wave surf waves, wakeboard waves and wakeboat waves on the lake. Wakesurf waves are created by filling only one side of the boat's ballasts and sailing at a fairly low speed (10 mph, 16.1 km / h). In the case of wakeboarding waves, both sides of the ballast are filled, and the boat use moves at a speed of 20 mph (32.2 km / h).
When will wakeboat moves from one place to another, the average speed of movement is 30 miles/h (48.3 km/h), but it moves at this time with these empty ballasts. The sampling plan was developed to measure the amount of energy that arrives at the shoreline and the resuspension of sediments to the shoreline, according to the three different types of movement (wakesurf waves, wakeboard waves and moving waves). ), three distances from shore and six sampling sites (3 per lake, Appendix 1).
Choice and characterization of sites - type of shoreline Site selection was designed to obtain different types of shoreline slope, with the goal of confirming whether the inflow and resuspension of sediments are influenced by bank slope (Sorensen 1997). Lovering and Memphremagog lakes were sampled at three different sites on each lake (Appendix 1) in order to obtain a slope gradient representative of the lakes in the region. The sampling took place on August 4, 5 and 6, 2013, between 8 am and 8 pm For each of the sites sampled, the shoreline slope was calculated from bathymetric charts based on the distance from the shoreline to the location in the lake where the water reached a depth of 3.05 m (10 ft. bathymetric map ).
Figuere 2. Illustration of the calculation of coastal slopes of sampling sites
Once the slopes were calculated (Table 1), the six sites were separated into steep-slope sites ( 0.1 mm -1 ) or soft (<0.1 mm -1 ). Table 1. Characteristics of sampled sites.
Dated Shore slope (mm - Type of slope Lake Site sampling 1 ) August 4, LOV1 0096 fresh 2013 August 5, LOV2 0022 fresh Lovering 2013 August 5, LOV3 0044 fresh 2013 August 5, MEM1 0203 acute 2013 August 5, MEM2 0131 acute Memphremagog 2013 August 6, MEM 3 0299 acute 2013
Sampling Resuspension of sediments To measure resuspension of sediment, a water sample was taken before (A) and after (B) each of the boat passages at each sampling site. Resuspension represents the difference in the amounts of suspended sediment measured between the two samples (BA). The baseline concentration of each site was established as the first sample collected at this site.
Turbulent kinetic energy The energy provided by the waves of wakeboats was measured using a micro-ADV (Acoustic Doppler Velocimeter), which makes it possible to measure the speed of water in all three dimensions at a high frequency (25 times / second, Figure 3). Figure 3. Example representing the speed (ms -1 ) of the dimensions x (red), y (green) and z (blue) for a period of normal waves, and during the passage of the boat wave (wave train).
Turbulent kinetic energy (TKE ) contained in a wave (created by a boat or otherwise) can be calculated by knowing the three-dimensional velocities as it passes, according to the equation : TKE=1/2 (x2+y2+z2) , where z, y and z are the micro-turbulence velocities measured in the three dimensions (Wist 2004).
This type of measurement makes it possible to estimate the energy dissipation rate (ε) which is also a measure of energy production when the system is in equilibrium. These three- dimensional velocity measurements are then decomposed into a power spectrum (Figure 4) whose Kolmogorov theory (1941) provides the characteristics according to the equation:
where S (f) is the spectral density at the frequency f (Hz), u rms can be considered as the average advective velocity (cm / s), C f is a constant, and ε is the energy dissipation rate (m 2 s - 3 ). Details of this methodology can be found in Vachon, Prairie, & Cole (2010). (From Vachon, Prairie and Cole, 2010) Figure 4. Power Spectrum Example for Calculation of Energy Dissipation
Using the maximum peak of the power spectrum obtained for each wave train and dividing it by the sampling frequency (25 / second), we obtain the number of waves present in each wave train. This number of waves is then divided by the length of the wave train (number of waves / wave length) to obtain a number of waves / second for each wave train.
Assessment of normal conditions Shoreline impacts under normal conditions, ie without boat passage, were assessed using the same device used for energy measurements caused by wakeboat passage. These data made it possible to evaluate the natural impact of the waves generated by the wind and this, for each of the sites.
Laboratory analysis Water samples taken before and after each boat trip were analyzed in the laboratory. For each sample, a volume of 250 mL of water was filtered through 934-AH RTU filters (Glass Microfiber filters, 47 mm, prewashed and pre-weighed, Whatman) within 72 hours of field sampling. Within 7 days, the filters were dried for one hour in an oven at 103 ° C ± 2 ° C, then kept in a desiccator for 30 minutes to remove all traces of moisture. The filters were finally weighed with a microbalance having an accuracy of 0.0001 g, to obtain the quantity of dry material and thus of sediment contained in the 250 ml water sample. The result was then converted to mg / L (Gray et al 2000, Environmental Sciences Section 1993).
Statistical analyzes The BACI protocol (Before-After-Impact-Control) was used as an experimental design for statistical analysis (Stewart-Oaten, Murdoch and Parker 1986). This type of sampling makes it possible to compare a site before and after a disturbance, for different types of situation. Here we compared the difference between the wake wave measurements and the normal wave measurements for each type of trip, each shore distance and at each sampling site. Analysis of variance (ANOVA), mean comparisons (t-test) and linear regressions were performed with the JMP software to analyze the data.
Limitations of the study As part of this study, only two lakes were sampled (Memphremagog and Lovering) at three sites each. Thus, some features of the lakes in the area are therefore unlikely to be represented by the sampling plan. In addition, three typical trips of wakeboat type boats were used in the sampling plan (wakeboard, wakesurf, on the move). In reality, the energy experienced by the shore is probably much more varied, because different types of passage, at variable speeds, follow each other in time.
In addition, in the case of sediment resuspension, the results showed lower sediment levels than expected and were very close to the detection limit of the method used. They are therefore not as accurate as desired and should therefore be considered very conservative.
RESULTS AND DISCUSSION
In this study, we analyzed the variations in energy (TKE) and resuspension of sediments caused by wakeboat waves upon their arrival at the shore, by varying the type of wakeboat movement, the distance from the shore to which it is situated, and the slope of these shores. This section opens with the overall results, that is, the results of all passage types, all shore distances and all shore slopes combined, as well as the six sites combined (ie three at Lovering Lake and three at Lake Memphremagog). In the following sections, the following results are presented according to the type of displacement of the wakeboat (wakesurf, wakeboard and on the move) and thus of the type of waves, according to the distance of the shore (100m, 150m, 200m) (320 ft, 492 ft, 620 ft) and following the slopes of the coast. A section also discusses some characteristics of the different types of waves produced.
Table 2 presents the average values obtained during the sampling in the two lakes. The results show that waves created by the wakeboat cause a significant increase (on average, 4 times higher) and still significant of the amount of energy (TKE) that reaches the shore, compared to normal conditions (ie without passing through boat). This general result applies for all types of passage, all distances from the shore and all shore slopes combined.
Table 2. Comparisons of results under normal conditions and during the passage of a wakeboat: speeds (average, maximum, minimum); turbulent kinetic energy (TKE), horizontal energy (ε x ) and vertical energy (ε z ); suspended sediment
Normal displacement t-test n Average speedcm s -1 3.04 6.27 <0.0001 * 215 Maximum cm s - speed 1 10.58 20.39 <0.0001 * 214 Minimum cm s - speed 1 0.08 0.12 0.0003 * 214 m2 s- TKE 2 7.91 31.81 <0.0001 * 209 Suspended mg L-1 Sediments 0.57 1.16 <0.0001 * 215
Normal displacement t = t estn
Average speed cm s -1
Maximum speed
Minimum speed
TKE
Suspended sediment
Note : We considered the differences to be significant at a threshold of p <0.05
Similarly, the passage of a wakeboat creates waves carrying considerable energy to directly induce a sediment resuspension statistically significant, in average 2 times higher than in normal conditions (Table 2), and this for all types of displacement, all distances and all slopes combined.
Turbulent kinetic energy (TKE) Figure 5 shows the TKE results from the distance between the boat passage and the shore (100m, 150m, 200m) and the type of passage, ie the TKE measurements for all types of crossing (Figure 5a), for wakesurf ( 10 miles / hr; (Figure 5b), wakeboarding ( 20 miles / hr, Figure 5c) and moving ship ( 30miles / hr, Figure 5d). Our results show that, for each type of boat passage, regardless of the distance, there was always a significant increase in the amount of energy present in the wakeboat wave train (Figure 5) that reached the shore ( pale gray), compared to normal conditions (dark gray). Figure 5. The energy (TKE) present in normal (dark gray) waves and that in waves after the passage of a wakeboat at 100, 150 and 200 m from the shore, and depending on the type of passage of the boat (a: all types of passage combined, b: 10 miles / h, c: 20 miles / h, d: 30miles / h). Note : The letters a and b different above the columns mean a significant difference (p <0.05). Having thus established that all the passages contain a significantly higher energy than under normal conditions, comparisons will be made between the different types of passage and the different distances from the shore.
Figure 6 shows the additional energy induced by the passage of a wakeboat, the difference between the energy in normal conditions and that measured during the passage of the wakeboat (TKE wave - TKE normal).
Two types of results are presented here. On the one hand, the additional energy induced is presented according to the use made of the boat ( wakesurf, wakeboard, on the move ), and therefore according to its speed (10, 20 or 30 miles / h), and according to the distance of the boat in relation to the shore (a: 100 m, b: 150 m, c: 200 m). Figure 6. The additional energy induced by the passage of a wakeboat (TKE wave - normal TKE) depending on the type of passage (10, 20 and 30 mph) and the distance to the shore (a: 100 m; b: 150 m; c: 200m) and that induced along the distance to the bank (100, 150 and 200 m) and according to the type of passage (d: 10 miles / h; e: 20 miles / h; f: 30 miles / h). Note : The letters a and b different above the columns mean a significant difference (p <0.05)
This first series of graphs makes it possible to compare the effect of different uses of the boat for the same distance from the shore: for example, the impact of the practice of wakesurfing ( 10 miles / h) at 100 m from shore (Figure 6a ) is much more important than that of the boat on the move (30 miles / h). In fact, the energy created by the wakesurf is 1.7 times higher than that produced by the boat on the move, despite its speed of 30 miles / h. In the case of other distances to shore (Figure b and c), the differences are not significant, although we see a trend between the distance of 300 m, and that of 100 m.
The second series of graphs in Figure 6 allows to reverse the analysis, ie to compare the amount of additional energy induced by the distance to the bank (100, 150 and 200 m) and according to the use of the boat, and therefore according to its speed (d: 10 miles / h; e: 20 miles / h; f: 30 miles / h).
This second series of graphs shows that the additional energy induced when the boat passes 100 m from the shore is 2 times higher than that induced by a passage to 200 m. This difference according to the distance from the shore is significant only in the case of waves of wakesurf (Figure 6d), although such a tendency is observable during waves of wakeboard and in displacement (Figure 6e and f).
Resuspension of sediments Figure 7 shows the amounts of sediment resuspended for each distance between the boat passage and the shore (100m, 150m, 200m); Figure 7a presents the results for all types of crossings combined, Figure 7b, those for wakesurf waves, Figure 7c, those for wakeboard waves and Figure 7d, the results for traveling waves.
Figure 7 shows that, in general, the passage of a vessel creates a resuspension of sediments that is significantly greater than that under normal conditions: this is the case with waves of wakesurf (10 miles / h, Figure 7b). and moving waves (30 mph, Figure 7d), when boats are traveling at 100m or 150m. from the shore. When the boat passes 200 m, there is no significant change in the resuspension of the sediments. There are contrary results for wakeboard crossings (20 miles / h, Figure 7c), significant resuspension only at 200 m but not at 100m or 150m. Figure 7. Resuspension of sediments caused by normal waves (dark gray) and caused by waves following the passage of a wakeboat at 100, 150 and 200 m depending on the type of passage (a: all types of passage, b: 10 miles / h, c: 20 miles / h, d: 30 miles / h).
Note : The same letters above the columns mean that there is no significant difference in effects between normal conditions and those caused by wakeboat waves .
Figure 8 (next page) shows the amounts of sediment resuspended in two forms of results. The first set of graphs shows the results for each type of trip ( wakeboat: 10 miles / h, wakeboard: 20 miles / h, on the move: 30 miles / h) for a distance of 100m (Figure 8a), a distance of 150m (Figure 8b) and a distance of 200 m. (Figure 8c). The second series presents the results according to the distance of the shoreline (100m, 150 and 200 m) according to the type of use of the boat, namely wakesurf (10 miles / h, Figure 8d), wakeboard (20miles / h Figure 8d) and on the move (30 mph, Figure 8f).
c: Figure 8. The resuspension of additional sediments induced according to the type of passage (10, 20 and 30 miles / h) and the passage distance (a: 100 m, b: 150 m,200 m) and that induced depending on the distance of the bank (100, 150 and 200 m) and the type of passage (d: 10 miles / h; e: 20 miles / h; f: 30 miles / h;). Note : The letters a and b different above the columns mean a significant difference (p <0.05)
The first series of graphs, which compare the effects of resuspension between the types of displacement, shows that only waves of wakesurf (10 miles / h) created at a distance of 150 m from shore (Figure 8b) produce a discount. in suspension significantly higher than that of the other two types of displacement. In the second series of graphs, Figure 8d shows that waves of wakesurfing create sediment resuspension greater than 100 and 150 m from the bank, compared to the distance of 200 m. The few significant differences between the results, despite apparently different mean values, can be explained by the large variability of the data, probably due to the lack of sensitivity of suspended sediment measurements.
Distance from the bank As expected, the amount of energy reaching the shore decreases with the distance of the wakeboat passages. Our protocol did not allow us to precisely measure the distance from the shore where no change of energy is visible on arrival at the shore. However, on the basis of the data recorded for all types of displacement, if the linear trend observed between the distances studied and the effects measured at the shore (TKE, resuspension of the sediments) is prolonged, it is possible to estimate approximate distance. Figure 9 shows the results of these calculations for each measured effect.
Figure 9. Linear regression of a) energy (TKE) and b) suspended sediment, as a function of shore distance for Lovering (light gray) and Memphrémagog (black) lakes. Note: The gray horizontal line represents energy level (a) and suspended sediment (b) respectively under normal conditions.
Figure 9 shows the results of the extrapolation of measurements to estimate the distance at which there would be no measurable energy input effects (TKE, Figure 9a) or resuspension of sediment (Figure 9b). In these figures, the results for Lake Lovering are represented by dots and a pale gray line, and those for Lake Memphremagog, in black dots and lines.
We first assessed the wakeboats' wake-up distance at which the impact of the wave on the shore is equivalent to that of normal conditions, ie 5.5 m 2 / s 2 for TKE, and 0.57 mg / L for sediments. in suspension. The normal values of TKE and suspended sediment are represented by a gray horizontal line. On the basis of the energy data (TKE, Figure 9a), the displacement distances equivalent to normal conditions are 268 m from shore for Lake Memphremagog and 312 m from shore for Lovering Lake. In the case of suspended sediments (Figure 9b), the estimated distances are 286m (Memphremagog) and 206m (Lovering).
According to our calculations, the distance at which the wakeboats would have effects similar to those under normal conditions is approximately, on average for the two lakes, 300 m from the shore in terms of energy, and 250 m from the shore. shore for suspended sediments. Based on these results, we posit that 300 m represents a reasonable distance beyond which the waves generated by the wakeboats would be largely dissipated before their arrival on the banks and would therefore have a negligible effect. On this basis and if the objective is to eliminate any impact on the shoreline that wakeboat passages could cause, we have transposed these results on a map for each lake (next page: Memphrémagog: Figure 10a; Lovering: Figure 10b) , to represent the navigable area (in dark gray) for wakeboats, in the case of a regulation limiting their use at a distance of 300 m from the lakeshore.
Figure 10. Map of the navigable area by wakeboats (dark gray) following a regulation limiting their activity to more than 300 m from the shores of lakes Memphrémagog (a) and Lovering (b).
Impact of shoreline slope on energy reaching the shoreline According to the literature, the level of energy arriving at the shore is expected to be a function of the slope of the coastline. We wanted to evaluate this hypothesis by linking the slopes of the coast of each site with the energy (TKE), measured under normal conditions and then during the passage of a wakeboat, all types of travel combined and all distances combined.
Our results show that, under normal conditions, the energy level that reaches a bank with a steep slope (acute: 0.1 mm -1 ) is not significantly different from that arriving at the bank with a slight slope ( soft: <0.1 mm -1 ). This is shown in Figure 11a, where energy values (TKE) are found under normal conditions with gentle slope (light gray) and acute slope ( dark gray ).
On the other hand, when increasing energy reaching the shore (with the passage of a wakeboat), the acute slopes receive a significantly higher energy (Figure 11b). Indeed, when the slope of a coastline is acute, the wave meets less quickly the bottom of the littoral and the energy
of the wave dissipates so less quickly. The energy that arrives at the shore is then much higher, leading to a greater impact on the resuspension of the sediments and possibly on the erosion of the bank.
at b Figure 11. Energy (TKE) reaching the shoreline for sites with acute (dark gray) or soft (pale gray) slope slope for normal (a) and wakeboat (b) waves. Note: The asterisk (*) represents the significant increase (p <0.05).
Coastal slope and TKE data were used to relate them in a regression analysis (page 12), under normal conditions (Figure 12a) and when passing a wakeboat (Figure 12b). As seen previously, under normal conditions (Figure 12a), there is little difference between the energy that arrives on a low-slope coastline (1st point down, in Figure 12a) and the energy that arrives on a coastline of acute slope (last point at the top, same figure). On the other hand, with the large amount of energy present in the waves caused by the passage of a wakeboat (Figure 12b), the impact of the slope of the coastline is much more important. The effect of wakeboat waves on energy (TKE) at the site that has the littoral with the steepest slope (last point at the top, Figure 12b) is much larger than for the site that has the littoral with the most Slow slope (1st point down, same figure).
Figure 12. Linear Regression between Energy (TKE) and Shoreline Slope: a) under normal conditions and b) during the passage of a wakeboat wave train for 5 sampled sites. Note : The LOV2 site has been eliminated from shoreline slope analyzes as its very small and very long slope eliminates the trends observed here.
Characteristics of the waves In addition to the previous information, we have characterized waves and wave trains, to assess their impact on the shores. According to our results, the very short and intense wakesurf wave train has the most impact when it reaches the shore because it contains much more energy (Figures 5 and 6). Indeed, despite a shorter average wave train duration (52.5 s) and a lower number of waves per second (0.54 wave s -1 ), the maximum speeds reached by the waves are the highest ( 25.0 ms -1 ), causing significant resuspension of sediments during the passage of these waves (Table 3).Indeed, the higher energy is concentrated in a small number of waves, which gives it more power.
The wakeboard wave train is much longer in duration (71.8 s) but, despite a fairly large increase in energy (Figure 5) and maximum speed (21.1 ms -1), we were unable to detect a significant resuspension of sediment. The wave train would become too large to have a major impact on the sediments.
Table 3. Average wave train duration (sec), number of waves per wave train length, and maximum speed (ms -1 ) for different shore distances (100, 150, 200 m) and the type of displacement of the wakeboat
All Distance Wakesurf Wakeboard Moving confused All confused - 52.47 71.79 65.46 Duration of the wave 100 m 47.64 40.42 54.03 48.6 train (sec) 150 m 62.83 52.36 69.96 64.64 200 m 80.63 64.63 89.92 83.13 All confused - 0.54 0.60 0.65 Number of waves per 100 m 0.59 0.52 0.59 0.67 length (wave s -1) 150 m 0.60 0.55 0.61 0.64 200 m 0.60 0.59 0.59 0.64 All confused - 25.04 21.07 15.94 Maximum speed (ms- 100 m 22.17 29.3 23.16 16.7 1 ) 150 m 20.18 25.46 20.27 15.97 200 m 17.99 20.36 19.96 15.14
The traveling wave train has an intermediate duration (65.5 s); it contains less energy and has a lower maximum speed (15.9 ms -1) than the other two types of wave trains, but it still has a considerable impact on the shoreline (Table 3 and Figures 7 and 8).). This trend for each of the three wave types remains the same depending on the distance from the shore (Table 3). Thus, the number of waves per duration of the wave train is not a function of the distance from the shore (p> 0.05). On the other hand, the wakesurf wave train contains significantly fewer waves, regardless of the distance from the shore (p <0.0001 *, for the three distances and all distances: Table 3).
The power of a wave train is thus strongly influenced by the intensity that each of the waves constituting it with the capacity to accumulate. .CONCLUSION
As a result of this experimental study, it is possible to establish that the wakeboat boat passage causes a considerable impact on the shore when it passes 100 m from the shore, and that all passages within 300 m significantly add energy to naturally occurring waves (Figure 9). In addition, the waves created by a wakeboat to wakesurf (1 side of ballast filled) are the ones that have the greatest impact when they arrive at the shore, given the large amount of energy contained in their short train of waves, which contains few waves. Due to their much longer waves and more waves, wakeboard waves (2 sides of ballasts filled) and the wakeboat (empty ballasts) have a less severe impact on the shore, with the energy distributed throughout the waves. the entire duration of the wave train. Nevertheless, it must be remembered that all the boat passes observed in this study carry a significantly higher amount of energy to shore than in normal conditions.
The energy present in the wave train created by the wakeboats causes a resuspension of the sediments and probably also an accelerated erosion of the banks.
According to the findings of this research and to eliminate any additional impact on the shoreline caused by wakeboat crossings, we suggest that a regulation limit the passage of wakeboat boats on lakes at least 300 m from shore, in order to avoid erosion (Figure 9). The navigable areas illustrated by the maps in Figure 10 were based on this 300m distance from the shorelines for the two study lakes (Memphremagog: Figure 10a; Lovering: Figure 10b).
BIBLIOGRAPHY
Environmental Sciences Section. 1993. ESS Method 340.2: Total Suspended Solids, Mass Balance (Dried at 103-105EC), Volatile Suspended Solids (Ignited at 550EC). Gray, JR, Glysson, GR, Turcios, LM and Schwarz, GE. 2000. Comparability of suspended sediment concentration and total suspended solids data. US Geological Survey: Water Resources Investigation Report, Vol. 00-4191, No. 1-14. Hill, DF, Beachler, MM and Johnson, PA. 2002. Hydrodynamic impacts of commercial Jet- boating on the Chilkat river, Alaska. Keenan, RJ and Kimmins, JPH. 1993. The ecological effects of clear-cutting. About. rev., vol. 1, p. 121-144. Kolmogorov, AN. The local structure of turbulence in incompressible viscous fluid for very large Reynolds numbers. Dokl. Akad. Nauk SSSR, vol. 30, p. 299-303. MRC Memphrémagog. 2011. Map of nautical regulation at Lovering Lake. Government of Quebec. Retrieved 18 December 2013 inhttp://www.mrcmemphremagog.com/pdf/Patrouille %20nautique/Cartes/Carte%20Lovering- FR.pdf MRC Memphrémagog. 2013. Map of nautical regulations at Lake Memphremagog. Government of Quebec. Retrieved December 18, 2013 from http://www.mrcmemphremagog.com/pdf/Patrouille%20nautique/Cards/Carte%20Memph- EN.pdf Péloquin-guay, M. 2013. Evaluation of the effect of boat waves on the hydraulic conditions near riverbanks in the middle of the river. Montreal university. Sorensen, RM. 1997. Prediction of Vessel-Generated Waves with Reference to Cells. Technical input, Department of Civil and Environmental Engineering, Lehigh University. Stewart-Oaten, A, Murdoch, WW and Parker, KR. 1986. Environmental impact assessment: "Pseudoreplication" in time? Ecology, vol. 67, No. 4, p. 929-940. Vachon, D, Prairie, YT and Cole, JJ. 2010. The relationship between near-surface turbulence and gas transfer velocity in freshwater systems and its implications. Limnology and oceanography, vol.55, No. 4, p. 1723-1732. Wist, HT. 2004. Statistical properties of successive ocean wave parameters. Faculty of Engineering and Technology, Norvegian University of Science and Technology. NOTES
Appendix 1. Sampling sites in Lovering Lake and Lake Memphremagog
Appendix 2. Nautical Regulations Map of Lovering Lake
Appendex 3. Maps of the Lake Memphremagog nautical regulation
Appendix 3. Raw Data Tables of Physical Parameters
Duration Number Distance Epsilon Speed Average Maximum Minimum Number of the / Date of taking from TKE z (miles speed speed speed of waves wave Length samples Lake Site Period shore (m 2 s -2 ) (m 2 s - / h) (ms -1 ) (ms -1 ) (ms -1 ) per train train (wave (m) 3) (sec) s -1) 3,8E- 08/04/2013 Lovering LOV1 Normal 10 100 2.41 21.52 0.04 4.38 08 2,2nd- 08/04/2013 Lovering LOV1 Wave 10 100 6.49 25.81 0.10 33,07 29.46 62.20 0.47 07 2,2nd- 08/04/2013 Lovering LOV1 Normal 10 150 1.13 17.33 0.02 0.96 08 1.4E- 08/04/2013 Lovering LOV1 Wave 10 150 6.02 25.32 0.05 29,52 43.69 78,88 0.55 07 6,7E- 08/04/2013 Lovering LOV1 Normal 10 150 1.23 4.82 0.03 1.12 08 6,7E- 08/04/2013 Lovering LOV1 Wave 10 150 5.75 19.65 0.12 23.54 31.83 67.64 0.47 08 6,0E- 08/04/2013 Lovering LOV1 Normal 10 200 2.85 10.21 0.06 5.96 08 3.3E- 08/04/2013 Lovering LOV1 Wave 10 200 5.46 17.09 0.02 21,06 29.49 53.04 0.56 08 1.6E- 08/04/2013 Lovering LOV1 Wave 10 100 6.82 20.54 0.10 33.45 25.37 51.80 0.49 07 3.3E- 08/04/2013 Lovering LOV1 Normal 10 100 1.89 8.53 0.07 2.54 08 1.7E- 08/04/2013 Lovering LOV1 Wave 10 200 5.03 14.77 0.13 16.87 43,11 74.84 0.58 08 1.5E- 08/04/2013 Lovering LOV1 Normal 10 200 2.28 7.64 0.12 3.89 07 1.5E- 08/04/2013 Lovering LOV1 Normal 20 200 1.91 8.52 0.02 3.11 07 8,0E- 08/04/2013 Lovering LOV1 Wave 20 200 4.99 18,88 0.14 18.53 51.66 90.40 0.57 08 08/04/2013 Lovering LOV1 Normal 20 150 2.09 12,40 0.11 3.37 2,1E- 07 08/04/2013 Lovering LOV1 Wave 20 150 5.48 17.55 0.02 21,90 1.3E- 38,01 63.36 0.60 07 08/04/2013 Lovering LOV1 Normal 20 200 2.01 8.02 0.04 3.12 2.5E- 07 08/04/2013 Lovering LOV1 Wave 20 200 4.67 19.31 0.07 16.57 1,1E- 58.45 96.60 0.61 07 08/04/2013 Lovering LOV1 Normal 20 100 2.66 7.05 0.04 4.74 2.5E- 07 08/04/2013 Lovering LOV1 Wave 20 100 6.30 19,08 0.34 29,20 2,1E- 27.76 51.28 0.54 07 08/04/2013 Lovering LOV1 Normal 20 100 1.58 6.38 0.05 1.81 5,4E- 08 08/04/2013 Lovering LOV1 Wave 20 100 5.84 20.49 0.04 26.12 1.4E- 37.14 59.84 0.62 07 08/04/2013 Lovering LOV1 Wave 20 150 4.47 17,06 0.11 14.98 1.7E- 66.39 103.28 0.64 07 08/04/2013 Lovering LOV1 Normal 20 150 2.38 12.37 0.06 3.86 1,1E- 07 08/04/2013 Lovering LOV1 Normal 30 150 1.59 5.03 0.07 1.72 9,9E- 08 08/04/2013 Lovering LOV1 Wave 30 150 3.17 9.14 0.03 6.92 5,0E- 53.36 81.52 0.65 08 08/04/2013 Lovering LOV1 Wave 30 200 3.83 11.47 0.10 10.25 3.3E- 26.28 38.32 0.69 08 08/04/2013 Lovering LOV1 Normal 30 200 1.26 5.64 0.02 1.10 4.4E- 08 08/04/2013 Lovering LOV1 Normal 30 100 1.61 0.05 10.50 2,4E- 07 08/04/2013 Lovering LOV1 Wave 30 100 3.78 13,32 0.01 10.26 5,2E- 22.27 33.40 0.67 08 08/04/2013 Lovering LOV1 Normal 30 150 1.55 5.18 0.04 1.62 9,5E- 08 08/04/2013 Lovering LOV1 Wave 30 150 3.14 11.06 0.04 7.13 9,9E- 52.16 79.68 0.65 08 08/04/2013 Lovering LOV1 Wave 30 100 5.06 14.41 0.08 18.49 8,7E- 39.36 59.04 0.67 08 08/04/2013 Lovering LOV1 Normal 30 100 1.94 8.15 0.00 2.78 9,3E- 08 08/04/2013 Lovering LOV1 Wave 30 200 3.70 11.51 0.04 10.04 5,8E- 67.91 99.04 0.69 08 08/04/2013 Lovering LOV1 Normal 30 200 1.54 5.75 0.05 1.68 6,1E- 08 08/05/2013 Lovering LOV2 Normal 10 200 3.95 16,21 0.15 11.76 9,4E- 07 08/05/2013 Lovering LOV2 Wave 10 200 6.70 21.41 0.05 34.65 3.5E- 53,90 89.84 0.60 07 Duration Number Distance Epsilon Speed Average Maximum Minimum TKE Number of the / Date of taking from z Lake Site Period (miles speed speed speed (m 2 s -2 of waves wave Length samples shore (m 2 s - / h) (ms -1 ) (ms -1 ) (ms -1 ) ) per train train (wave (m) 3) (sec) s -1) 1.5E- 08/05/2013 Lovering LOV2 Wave 10 100 10.17 28.68 0.13 79.82 16,06 36,80 0.44 06 3,1E- 08/05/2013 Lovering LOV2 Normal 10 100 3.98 12.77 0.09 11.78 07 1,9E- 08/05/2013 Lovering LOV2 Normal 10 100 3.44 11.16 0.00 8.91 07 1,1E- 08/05/2013 Lovering LOV2 Wave 10 100 10.65 30.38 0.30 89.23 16.93 31,04 0.55 06 2,9E- 08/05/2013 Lovering LOV2 Normal 10 150 3.26 10.82 0.07 7.86 08 4,8E- 08/05/2013 Lovering LOV2 Wave 10 150 8.40 28,02 0.04 51.91 27.26 49.04 0.56 07 5,9E- 08/05/2013 Lovering LOV2 Normal 10 200 3.27 11.53 0.09 8.14 08 8,2E- 08/05/2013 Lovering LOV2 Wave 10 200 8.20 25.64 0.09 49.81 24.29 46.56 0.52 08 3.0E- 08/05/2013 Lovering LOV2 Wave 10 150 7.71 25.43 0.09 43.57 25.92 46.44 0.56 07 2,1E- 08/05/2013 Lovering LOV2 Normal 10 150 3.72 10.84 0.09 9.76 07 2.7E- 08/05/2013 Lovering LOV2 Wave 20 150 8.10 28.32 0.10 48.36 31.67 50.80 0.62 07 1.6E- 08/05/2013 Lovering LOV2 Normal 20 150 5.00 15,52 0.10 18.12 07 1,9E- 08/05/2013 Lovering LOV2 Wave 20 200 7.82 31.55 0.23 47.66 36.85 64.48 0.57 07 1.3E- 08/05/2013 Lovering LOV2 Normal 20 200 6.20 20.47 0.09 29.09 07 1,8E- 08/05/2013 Lovering LOV2 Wave 20 150 8.32 29,10 0.13 52.70 24.47 41,12 0.60 07 2,2nd- 08/05/2013 Lovering LOV2 Normal 20 150 5.09 19.96 0.04 19.49 07 1,9E- 08/05/2013 Lovering LOV2 Normal 20 200 6.09 19.47 0.04 27.84 07 2,1E- 08/05/2013 Lovering LOV2 Wave 20 200 7.86 25.67 0.14 46.30 35,13 58.56 0.60 07 6,7E- 08/05/2013 Lovering LOV2 Normal 20 100 4.51 16,30 0.07 15.42 08 5,4E- 08/05/2013 Lovering LOV2 Wave 20 100 8.07 28.93 0.16 50.20 31.75 50.92 0.62 07 1,8E- 08/05/2013 Lovering LOV2 Normal 20 100 4.76 14.83 0.17 16.29 07 4.2E- 08/05/2013 Lovering LOV2 Wave 20 100 8.51 30.62 0.25 53.98 24.60 40.40 0.61 07 1,8E- 08/05/2013 Lovering LOV2 Normal 30 100 4.94 14.93 0.19 17,60 07 1.0E- 08/05/2013 Lovering LOV2 Wave 30 100 7.63 19.41 0.36 39.06 30.23 34.96 0.86 07 1,1E- 08/05/2013 Lovering LOV2 Normal 30 200 5.77 17.92 0.04 23.59 07 1.0E- 08/05/2013 Lovering LOV2 Wave 30 200 6.98 24.98 0.09 35.83 48.65 74.32 0.65 07 1.3E- 08/05/2013 Lovering LOV2 Normal 30 100 5.36 20.25 0.00 21,36 07 9,9E- 08/05/2013 Lovering LOV2 Wave 30 100 6.85 18.78 0.13 33.32 47.36 68.08 0.70 08 1,1E- 08/05/2013 Lovering LOV2 Normal 30 150 6.92 21,01 0.09 34.48 07 1.2E- 08/05/2013 Lovering LOV2 Wave 30 150 8.27 22.49 0.05 48.24 36.15 56.24 0.64 07 1,8E- 08/05/2013 Lovering LOV2 Normal 30 150 6.61 22.47 0.04 31.59 07 1.4E- 08/05/2013 Lovering LOV2 Wave 30 150 8.65 28.30 0.11 55,08 41.85 65.32 0.64 07 1.0E- 08/05/2013 Lovering LOV2 Normal 30 200 6.61 24.82 0.23 31.69 07 2,1E- 08/05/2013 Lovering LOV2 Wave 30 200 7.68 23.44 0.08 43.63 31.60 47,40 0.67 07 3.7E- 08/05/2013 Lovering LOV3 Wave 10 100 6.18 18.59 0.08 27.96 35,70 57.52 0.62 07 4,5E- 08/05/2013 Lovering LOV3 Normal 10 100 2.55 6.79 0.13 4.50 07 1,8E- 08/05/2013 Lovering LOV3 Wave 10 150 4.49 17.16 0.04 16,05 51.30 82.28 0.62 07 1.4E- 08/05/2013 Lovering LOV3 Normal 10 150 1.80 6.23 0.02 2.83 07 2.0E- 08/05/2013 Lovering LOV3 Wave 10 100 5.87 16.87 0.09 25.17 34,01 54,56 0.62 07 2,2nd- 08/05/2013 Lovering LOV3 Normal 10 100 1.96 6.67 0.03 2.80 08 1.2E- 0 8/05/2013 Lovering LOV3 Wave 10 200 5.19 17.27 0.08 20,14 50.02 87,88 0.57 07
Duration Numbe Distance Epsilon Speed Average Maximum Minimum TKE Number of the r / Date of taking from z Lake Site Period (miles speed speed speed (m 2 s -2 of waves wave Length samples shore (m 2 s - / h) (ms -1 ) (ms -1 ) (ms -1 ) ) per train train (wave (m) 3) (sec) s -1) 2.5E- 08/05/2013 Lovering LOV3 Normal 10 200 1.97 6.36 0.05 2.94 08 2.0E- 08/05/2013 Lovering LOV3 Wave 10 200 4.05 16.29 0.05 13.29 50.08 91.80 0.55 07 8,7E- 08/05/2013 Lovering LOV3 Normal 10 200 1.86 6.30 0.09 2.56 08 8,7E- 08/05/2013 Lovering LOV3 Normal 10 150 1.94 6.56 0.07 2.84 08 2,1E- 08/05/2013 Lovering LOV3 Wave 10 150 5.24 18.21 0.02 20,82 45.76 73.08 0.63 07 3,6E- 08/05/2013 Lovering LOV3 Wave 20 150 5.01 14.61 0.15 52.57 84.32 0.62 07 1.0E- 08/05/2013 Lovering LOV3 Normal 20 150 1.87 6.58 0.04 07 1,8E- 08/05/2013 Lovering LOV3 Normal 20 100 2.13 6.10 0.15 2.94 07 7,1E- 08/05/2013 Lovering LOV3 Wave 20 100 5.15 17.75 0.18 20.19 44.88 74,80 0.60 07 1,1E- 08/05/2013 Lovering LOV3 Wave 20 200 4.24 15,01 0.03 13.16 66.14 109.32 0.61 07 3.0E- 08/05/2013 Lovering LOV3 Normal 20 200 1.88 24.26 0.03 2.73 08 3.7E- 08/05/2013 Lovering LOV3 Wave 20 150 4.73 17.76 0.04 17,04 58.45 96.60 0.61 07 2.0E- 08/05/2013 Lovering LOV3 Normal 20 150 1.83 5.88 0.08 2.29 07 3.2E- 08/05/2013 Lovering LOV3 Normal 20 100 1.65 6.68 0.09 1.97 08 4.9E- 08/05/2013 Lovering LOV3 Wave 20 100 4.52 17.25 0.11 15.78 53.12 85.20 0.62 07 2,4E- 08/05/2013 Lovering LOV3 Normal 20 200 1.79 5.57 0.09 2.35 08 9,3E- 08/05/2013 Lovering LOV3 Wave 20 200 4.18 15.79 0.04 13.53 74.75 116.28 0.64 08 4.9E- 08/05/2013 Lovering LOV3 Normal 30 150 1.65 5.10 0.03 1.98 08 8,2E- 08/05/2013 Lovering LOV3 Wave 30 150 3.29 11.33 0.09 7.81 75.53 110.16 0.69 08 7,9E- 08/05/2013 Lovering LOV3 Normal 30 200 1.69 6.33 0.10 2.08 08 2.7E- 08/05/2013 Lovering LOV3 Wave 30 200 3.07 9.87 0.08 6.96 86.92 112,40 0.77 08 6,0E- 08/05/2013 Lovering LOV3 Wave 30 150 3.37 10.84 0.04 8.26 73.45 107.12 0.69 08 4,6E- 08/05/2013 Lovering LOV3 Normal 30 150 1.93 5.97 0.03 2.81 08 5,7E- 08/05/2013 Lovering LOV3 Wave 30 100 2.92 8.40 0.02 5.92 61.34 84,36 0.73 08 2.5E- 08/05/2013 Lovering LOV3 Normal 30 100 1.54 6.73 0.01 1.54 08 1.7E- 08/05/2013 Lovering LOV3 Wave 30 200 3.01 10,27 0.06 6.33 135.96 07 9,2E- 08/05/2013 Lovering LOV3 Normal 30 200 1.59 4.88 0.02 1.79 08 5,6E- 08/05/2013 Lovering LOV3 Wave 30 100 3.17 9.69 0.01 7.37 73.41 91.76 0.80 08 3,1E- 08/05/2013 Lovering LOV3 Normal 30 100 1.60 5.28 0.04 1.90 08 4.2E- 08/05/2013 Memphremagog MEM1 Normal 10 200 2.07 5.75 0.06 2.83 07 1.5E- 08/05/2013 Memphremagog MEM1 Wave 10 200 5.23 22.64 0.06 24.28 27.87 54.20 0.51 07 4.4E- 08/05/2013 Memphremagog MEM1 Wave 10 150 4.92 16.36 0.07 19.56 26.33 46.08 0.57 08 1,9E- 08/05/2013 Memphremagog MEM1 Normal 10 150 1.84 6.37 0.02 2.38 07 8,2E- 08/05/2013 Memphremagog MEM1 Wave 10 100 5.39 19.46 0.05 23,74 19.18 41.76 0.46 08 4,0E- 08/05/2013 Memphremagog MEM1 Normal 10 100 2.24 5.82 0.09 3.52 07 6,0E- 08/05/2013 Memphremagog MEM1 Normal 10 150 2.50 8.27 0.06 4.20 08 5,3E- 08/05/2013 Memphremagog MEM1 Wave 10 150 6.61 22.79 0.25 37,38 26.89 52.28 0.51 07 1,8E- 08/05/2013 Memphremagog MEM1 Wave 10 200 3.59 12.91 0.06 10.41 52.11 95.52 0.55 08 3,6E- 08/05/2013 Memphremagog MEM1 Normal 10 200 1.54 7.29 0.01 1.86 08 4.2E- 08/05/2013 Memphremagog MEM1 Wave 10 100 7.04 34.66 0.20 49.27 17.07 33,60 0.51 07 2,1E- 08/05/2013 Memphremagog MEM1 Normal 10 100 1.78 5.94 0.03 2.20 07 Duration Number Distance Epsilon Speed Average Maximum Minimum TKE Number of the / Date of taking from z Lake Site Period (miles speed speed speed (m 2 s -2 of waves wave Length samples shore (m 2 s - / h) (ms -1 ) (ms -1 ) (ms -1 ) ) per train train (wave (m) 3) (sec) s -1) 1.6E- 08/05/2013 Memphremagog MEM1 Normal 20 150 1.81 4.58 0.02 2.25 06 4.2E- 08/05/2013 Memphremagog MEM1 Wave 20 150 5.17 16.32 0.26 18.67 47.87 80.44 0.60 07 1.5E- 08/05/2013 Memphremagog MEM1 Normal 20 200 2.62 11.22 0.19 5.06 07 5,0E- 08/05/2013 Memphremagog MEM1 Wave 20 200 4.38 12.65 0.04 13.16 75.03 116.72 0.64 07 3,8E- 08/05/2013 Memphremagog MEM1 Wave 20 150 5.03 12.38 0.03 17.54 39.72 64,00 0.62 07 4.2E- 08/05/2013 Memphremagog MEM1 Normal 20 150 3.18 8.80 0.16 7.03 07 08/05/2013 Memphremagog MEM1 Normal 20 200 2.12 14.69 0.04 3.01 4,3E- 08/05/2013 Memphremagog MEM1 Wave 20 200 4.48 14.64 0.11 13.97 72.79 121.32 0.60 07 1.2E- 08/05/2013 Memphremagog MEM1 Normal 20 100 2.32 6.19 0.12 3.70 06 1.3E- 08/05/2013 Memphremagog MEM1 Wave 20 100 6.07 19.55 0.11 27.64 29.39 51.44 0.57 06 6,2E- 08/05/2013 Memphremagog MEM1 Wave 20 100 5.88 22.33 0.07 28.07 37,69 65.96 0.57 07 8,9E- 08/05/2013 Memphremagog MEM1 Normal 20 100 1.73 6.66 0.08 2.28 07 4,6E- 08/05/2013 Memphremagog MEM1 Normal 30 200 3.00 11.38 0.02 6.73 07 7,8E- 08/05/2013 Memphremagog MEM1 Wave 30 200 4.78 12.78 0.07 16,14 37.68 62.80 0.60 07 1.3E- 08/05/2013 Memphremagog MEM1 Wave 30 100 5.01 13.38 0.25 17,21 22.22 44.44 0.50 06 08/05/2013 Memphremagog MEM1 Normal 30 100 9.66 2.0E- 08/05/2013 Memphremagog MEM1 Wave 30 100 4.63 13,01 0.13 15.64 32.87 54.32 0.61 07 1.7E- 08/05/2013 Memphremagog MEM1 Normal 30 100 3.27 12.84 0.10 8.98 08 7,9E- 08/05/2013 Memphremagog MEM1 Wave 30 150 5.20 14,01 0.17 18.83 19.05 30.16 0.63 07 3.4E- 08/05/2013 Memphremagog MEM1 Normal 30 150 4.38 9.93 0.12 12.63 07 9,4E- 08/05/2013 Memphremagog MEM1 Normal 30 200 2.47 9.36 0.03 4.96 07 5,6E- 08/05/2013 Memphremagog MEM1 Wave 30 200 4.13 15.55 0.09 12.74 52.82 84.72 0.62 07 6,7E- 08/05/2013 Memphremagog MEM1 Normal 30 150 4.58 10.63 0.34 13.89 07 5,8E- 08/05/2013 Memphremagog MEM1 Wave 30 150 4.46 12.74 0.11 14.73 28.17 44,60 0.63 07 2.7E- 08/05/2013 Memphremagog MEM2 Normal 10 100 2.09 6.99 0.08 3.27 07 2,4E- 08/05/2013 Memphremagog MEM2 Wave 10 100 8.15 36.25 0.06 67.82 16,05 29.88 0.54 06 3,1E- 08/05/2013 Memphremagog MEM2 Wave 10 150 8.12 32.63 0.14 61.86 18,08 35.60 0.51 07 2.5E- 08/05/2013 Memphremagog MEM2 Normal 10 150 2.07 6.72 0.08 3.08 07 6.8E- 08/05/2013 Memphremagog MEM2 Normal 10 200 2.16 6.16 0.02 3.18 08 9,1E- 08/05/2013 Memphremagog MEM2 Wave 10 200 3.48 11.71 0.02 8.86 38.78 62.48 0.62 09 3,1E- 08/05/2013 Memphremagog MEM2 Normal 10 200 2.13 8.43 0.04 3.45 08 2,1E- 08/05/2013 Memphremagog MEM2 Wave 10 200 6.50 20,04 0.04 35.24 29.54 48.24 0.61 08 2.5E- 08/05/2013 Memphremagog MEM2 Wave 10 100 7.56 35,70 0.24 62.72 19,15 36.56 0.52 06 2,4E- 08/05/2013 Memphremagog MEM2 Normal 10 100 1.78 4.34 0.08 2.12 07 4.4E- 08/05/2013 Memphremagog MEM2 Wave 10 150 6.71 33.51 0.05 48.93 20,70 40,32 0.51 07 3.4E- 08/05/2013 Memphremagog MEM2 Normal 10 150 1.90 6.56 0.00 2.60 07 7,3E- 08/05/2013 Memphremagog MEM2 Normal 20 150 2.61 6.81 0.04 4.62 07 3.2E- 08/05/2013 Memphremagog MEM2 Wave 20 150 7.04 22.82 0.36 36.89 30.95 51.16 0.61 07 3,6E- 08/05/2013 Memphremagog MEM2 Wave 20 200 6.60 25.18 0.22 33.21 38.47 67.32 0.57 07 9,3E- 08/05/2013 Memphremagog MEM2 Normal 20 200 2.67 7.50 0.08 4.82 07 9,3E- 08/05/2013 Memphremagog MEM2 Normal 20 200 1.50 5.48 0.03 1.69 08 Duration Number Distance Epsilon Speed Average Maximum Minimum TKE Number of the / Date of taking from z Lake Site Period (miles speed speed speed (m 2 s -2 of waves wave Length samples shore (m 2 s - / h) (ms -1 ) (ms -1 ) (ms -1 ) ) per train train (wave (m) 3) (sec) s -1) 1,1E- 08/05/2013 Memphremagog MEM2 Wave 20 200 5.19 20.95 0.04 22.22 45.81 79.52 0.58 07 1.2E- 08/05/2013 Memphremagog MEM2 Wave 20 100 7.66 25.91 0.24 48.80 21.41 37.16 0.58 06 7,2E- 08/05/2013 Memphremagog MEM2 Normal 20 100 2.19 8.47 0.04 3.73 07 4.2E- 08/05/2013 Memphremagog MEM2 Wave 20 150 6.61 21.87 0.16 33.50 33.86 56.44 0.60 07 1.4E- 08/05/2013 Memphremagog MEM2 Normal 20 150 2.68 7.33 0.14 5.35 06 1.2E- 08/05/2013 Memphremagog MEM2 Normal 20 100 2.00 6.56 0.03 3.23 06 1.2E- 08/05/2013 Memphremagog MEM2 Wave 20 100 8.06 28.34 0.18 52.53 20,02 35.04 0.57 06 08/05/2013 Memphremagog MEM2 Normal 30 150 3.97 9.94 0.08 10.56 6,1E- 08/05/2013 Memphremagog MEM2 Wave 30 150 5.31 15,05 0.09 19.51 30.07 47,60 0.63 08 1.3E- 08/05/2013 Memphremagog MEM2 Normal 30 150 2.74 7.81 0.09 5.12 06 9,8E- 08/05/2013 Memphremagog MEM2 Wave 30 150 6.00 14.18 0.10 24.58 25.06 40,20 0.62 08 1.6E- 08/05/2013 Memphremagog MEM2 Normal 30 100 2.95 8.82 0.05 6.15 07 7,4E- 08/05/2013 Memphremagog MEM2 Wave 30 100 6.77 15,11 0.15 30.53 20.81 30.84 0.67 07 2,9E- 08/05/2013 Memphremagog MEM2 Normal 30 200 3.02 9.98 0.13 6.51 07 1,5E- 08/05/2013 Memphremagog MEM2 Wave 30 200 4.11 11,70 0,07 11,86 54,98 91,64 0,60 07 1,1E- 5/8/2013 Memphrémagog MEM2 Vague 30 100 7,43 24,18 0,23 40,52 16,86 29,04 0,58 07 1,3E- 5/8/2013 Memphrémagog MEM2 Normal 30 100 3,81 13,95 0,09 10,86 06 1,1E- 5/8/2013 Memphrémagog MEM2 Normal 30 200 2,66 6,73 0,14 4,66 06 5,1E- 5/8/2013 Memphrémagog MEM2 Vague 30 200 4,01 13,25 0,06 11,77 63,09 94,64 0,67 07 4,5E- 6/8/2013 Memphrémagog MEM3 Vague 10 200 11,09 35,95 0,39 15,15 29,88 0,51 07 1,0E- 6/8/2013 Memphrémagog MEM3 Normal 10 200 3,63 12,52 0,03 9,32 07 6,4E- 6/8/2013 Memphrémagog MEM3 Normal 10 200 3,73 13,26 0,08 10,30 08 2,0E- 6/8/2013 Memphrémagog MEM3 Vague 10 200 7,35 28,59 0,04 42,18 22,03 41,24 0,53 07 2,1E- 6/8/2013 Memphrémagog MEM3 Normal 10 150 3,65 14,11 0,07 10,67 07 1,1E- 6/8/2013 Memphrémagog MEM3 Vague 10 150 8,89 26,88 0,08 58,74 20,33 33,68 0,60 06 5,5E- 6/8/2013 Memphrémagog MEM3 Normal 10 100 4,34 12,23 0,02 13,07 07 6/8/2013 Memphrémagog MEM3 Vague 10 100 11,79 0,25 10,99 24,04 0,46 5,1E- 6/8/2013 Memphrémagog MEM3 Normal 10 100 3,95 11,26 0,09 11,15 07 4,8E- 6/8/2013 Memphrémagog MEM3 Vague 10 100 10,32 30,13 0,09 83,96 14,27 25,32 0,56 06 4,7E- 6/8/2013 Memphrémagog MEM3 Normal 10 150 4,21 16,18 0,09 12,52 07 1,7E- 6/8/2013 Memphrémagog MEM3 Vague 10 150 12,09 39,60 0,21 11,11 22,96 0,48 06 1,5E- 6/8/2013 Memphrémagog MEM3 Normal 20 100 5,06 16,63 0,28 18,94 06 2,1E- 6/8/2013 Memphrémagog MEM3 Vague 20 100 11,28 23,66 81,75 6,00 9,60 0,63 06 1,7E- 6/8/2013 Memphrémagog MEM3 Normal 20 150 6,81 18,52 0,23 06 6/8/2013 Memphrémagog MEM3 Vague 20 150 8,26 22,45 0,27 47,69 32,59 55,44 0,59 1,2E- 6/8/2013 Memphrémagog MEM3 Normal 20 150 6,01 19,64 0,18 06 3,6E- 6/8/2013 Memphrémagog MEM3 Vague 20 150 7,16 23,02 0,19 37,53 55,48 92,48 0,60 07 1,9E- 6/8/2013 Memphrémagog MEM3 Normal 20 200 4,73 12,86 0,09 16,05 06 1,1E- 6/8/2013 Memphrémagog MEM3 Vague 20 200 6,92 19,41 0,16 32,54 46,44 93,04 0,50 06 4,4E- 6/8/2013 Memphrémagog MEM3 Normal 20 200 4,22 12,14 0,04 12,62 07 9,5E- 6/8/2013 Memphrémagog MEM3 Vague 20 200 7,47 20,46 0,15 38,93 37,39 65,44 0,57 07 Durée Nombre du Nombre/ Vitesse Distance Vitesse Vitesse Vitesse TKE Epsilon Date de prise de train Longueur Lac Site Période (miles/h de la moyenne maximum minimum (m2s- z (m2s- d’échantillons vagues de (vague s- ) rive (m) (m s-1) (m s-1) (m s-1) 2) 3) par train vague 1) (sec) 9,4E- 6/8/2013 Memphrémagog MEM3 Vague 20 100 9,32 24,54 0,05 60,35 23,62 42,40 0,56 07 8,5E- 6/8/2013 Memphrémagog MEM3 Normal 20 100 4,29 12,59 0,03 13,00 07 5,6E- 6/8/2013 Memphrémagog MEM3 Vague 30 150 7,79 25,95 0,16 45,06 28,71 50,24 0,57 07 2,4E- 6/8/2013 Memphrémagog MEM3 Normal 30 150 4,25 8,81 0,14 12,89 06 3,8E- 6/8/2013 Memphrémagog MEM3 Normal 30 100 4,38 16,56 0,19 14,48 07 1,2E- 6/8/2013 Memphrémagog MEM3 Vague 30 100 8,18 25,11 0,04 47,33 21,28 36,20 0,59 06 7,3E- 6/8/2013 Memphrémagog MEM3 Normal 30 200 3,74 10,22 0,24 9,55 07 4,2E- 6/8/2013 Memphrémagog MEM3 Vague 30 200 6,41 18,95 0,10 27,01 46,96 78,28 0,60 07 6,4E- 6/8/2013 Memphrémagog MEM3 Normal 30 200 4,99 23,96 0,22 15,81 07 1,0E- 6/8/2013 Memphrémagog MEM3 Vague 30 200 6,15 17,90 0,19 25,59 40,03 77,84 0,51 06 3,0E- 6/8/2013 Memphrémagog MEM3 Normal 30 100 3,76 10,94 0,08 10,04 07 1,4E- 6/8/2013 Memphrémagog MEM3 Vague 30 100 8,35 25,62 0,34 51,91 23,35 35,76 0,65 06 2,8E- 6/8/2013 Memphrémagog MEM3 Normal 30 150 4,20 11,85 0,15 13,45 06 7,0E- 6/8/2013 Memphrémagog MEM3 Vague 30 150 6,64 16,61 0,14 29,18 41,87 62,80 0,67 07 Annexe 4. Tableaux des données brutes des valeurs de sédiments en suspension
Date of Speed Distance T0 (A) T1 (B) Resuspension taking (miles / from shore sediments sediments Lake Site Period (mg L -1 ) samples h) (m) (mg L -1 ) (mg L -1 ) 08/04/13 Lovering LOV1 Normal 20 200 0.4 1.6 1.2 08/04/13 Lovering LOV1 Wave 20 200 0.4 1.6 1.2 08/04/13 Lovering LOV1 Normal 20 150 0.4 2.8 2.4 08/04/13 Lovering LOV1 Wave 20 150 0.4 2.8 2.4 08/04/13 Lovering LOV1 Normal 30 150 0.4 0.4 0 08/04/13 Lovering LOV1 Wave 30 150 0.4 0.4 0 08/04/13 Lovering LOV1 Normal 20 200 0.4 0.4 0 08/04/13 Lovering LOV1 Wave 20 200 0.4 0.4 0 08/04/13 Lovering LOV1 Normal 20 100 0.4 0.4 0 08/04/13 Lovering LOV1 Wave 20 100 0.4 0.4 0 08/04/13 Lovering LOV1 Wave 30 200 0.4 0.4 0 08/04/13 Lovering LOV1 Normal 30 200 0.4 0.4 0 08/04/13 Lovering LOV1 Normal 10 100 0.4 0.4 0 08/04/13 Lovering LOV1 Wave 10 100 0.4 0.4 0 08/04/13 Lovering LOV1 Normal 30 100 0.4 0.4 0 08/04/13 Lovering LOV1 Wave 30 100 0.4 0.4 0 08/04/13 Lovering LOV1 Normal 20 100 0.4 2.4 2 08/04/13 Lovering LOV1 Wave 20 100 0.4 2.4 2 08/04/13 Lovering LOV1 Normal 10 150 0.4 -2.4 -2.8 08/04/13 Lovering LOV1 Wave 10 150 0.4 -2.4 -2.8 08/04/13 Lovering LOV1 Normal 30 150 0.4 2 1.6 08/04/13 Lovering LOV1 Wave 30 150 0.4 2 1.6 08/04/13 Lovering LOV1 Normal 10 150 0.4 3.2 2.8 08/04/13 Lovering LOV1 Wave 10 150 0.4 3.2 2.8 08/04/13 Lovering LOV1 Normal 10 200 0.4 0.4 0 08/04/13 Lovering LOV1 Wave 10 200 0.4 0.4 0 08/04/13 Lovering LOV1 Wave 30 100 0.4 0.4 0 08/04/13 Lovering LOV1 Normal 30 100 0.4 0.4 0 08/04/13 Lovering LOV1 Wave 20 150 0.4 0.4 0 08/04/13 Lovering LOV1 Normal 20 150 0.4 0.4 0 08/04/13 Lovering LOV1 Wave 10 100 0.4 0.4 0 08/04/13 Lovering LOV1 Normal 10 100 0.4 0.4 0 08/04/13 Lovering LOV1 Wave 10 200 0.4 08/04/13 Lovering LOV1 Normal 10 200 0.4 08/04/13 Lovering LOV1 Wave 30 200 0.4 0.4 0 08/04/13 Lovering LOV1 Normal 30 200 0.4 0.4 0 08/05/13 Lovering LOV2 Normal 30 100 0.6 8.2 7.6 08/05/13 Lovering LOV2 Wave 30 100 0.6 8.2 7.6 08/05/13 Lovering LOV2 Wave 20 150 0.6 0.6 0 08/05/13 Lovering LOV2 Normal 20 150 0.6 0.6 0
Date of Distance T0 (A) T1 (B) Speed Resuspension taking from shore sediments sediments Lake Site Period (miles / h) (mg L -1 ) samples (m) (mg L -1 ) (mg L -1 ) 08/05/13 Lovering LOV2 Normal 30 200 0.6 0.6 0 08/05/13 Lovering LOV2 Wave 30 200 0.6 0.6 0 08/05/13 Lovering LOV2 Normal 10 200 0.6 0.6 0 08/05/13 Lovering LOV2 Wave 10 200 0.6 0.6 0 08/05/13 Lovering LOV2 Normal 30 100 0.6 0.6 0 08/05/13 Lovering LOV2 Wave 30 100 0.6 0.6 0 08/05/13 Lovering LOV2 Wave 10 100 0.6 0.6 0 08/05/13 Lovering LOV2 Normal 10 100 0.6 0.6 0 08/05/13 Lovering LOV2 Wave 20 200 0.6 0.6 0 08/05/13 Lovering LOV2 Normal 20 200 0.6 0.6 0 08/05/13 Lovering LOV2 Wave 20 150 0.6 0.6 0 08/05/13 Lovering LOV2 Normal 20 150 0.6 0.6 0 08/05/13 Lovering LOV2 Normal 30 150 0.6 0.6 0 08/05/13 Lovering LOV2 Wave 30 150 0.6 0.6 0 08/05/13 Lovering LOV2 Normal 10 100 0.6 0.6 0 08/05/13 Lovering LOV2 Wave 10 100 0.6 0.6 0 08/05/13 Lovering LOV2 Normal 20 200 0.6 0.6 0 08/05/13 Lovering LOV2 Wave 20 200 0.6 0.6 0 08/05/13 Lovering LOV2 Normal 20 100 0.6 3.4 2.8 08/05/13 Lovering LOV2 Wave 20 100 0.6 3.4 2.8 08/05/13 Lovering LOV2 Normal 20 100 0.6 1.8 1.2 08/05/13 Lovering LOV2 Wave 20 100 0.6 1.8 1.2 08/05/13 Lovering LOV2 Normal 10 150 0.6 0.6 0 08/05/13 Lovering LOV2 Wave 10 150 0.6 0.6 0 08/05/13 Lovering LOV2 Normal 10 200 0.6 0.6 0 08/05/13 Lovering LOV2 Wave 10 200 0.6 0.6 0 08/05/13 Lovering LOV2 Normal 30 150 0.6 0.6 0 08/05/13 Lovering LOV2 Wave 30 150 0.6 0.6 0 08/05/13 Lovering LOV2 Normal 30 200 0.6 0.6 0 08/05/13 Lovering LOV2 Wave 30 200 0.6 0.6 0 08/05/13 Lovering LOV2 Wave 10 150 0.6 0.6 0 08/05/13 Lovering LOV2 Normal 10 150 0.6 0.6 0 08/05/13 Lovering LOV3 Normal 30 150 0.3 0.3 0 08/05/13 Lovering LOV3 Wave 30 150 0.3 0.3 0 08/05/13 Lovering LOV3 Normal 30 200 0.3 0.3 0 08/05/13 Lovering LOV3 Wave 30 200 0.3 0.3 0 08/05/13 Lovering LOV3 Wave 30 150 0.3 0.3 0 08/05/13 Lovering LOV3 Normal 30 150 0.3 0.3 0 08/05/13 Lovering LOV3 Wave 10 100 0.3 1.9 1.6 08/05/13 Lovering LOV3 Normal 10 100 0.3 1.9 1.6 08/05/13 Lovering LOV3 Wave 20 150 0.3 0.3 0 08/05/13 Lovering LOV3 Normal 20 150 0.3 0.3 0 08/05/13 Lovering LOV3 Normal 20 100 0.3 0.3 0 08/05/13 Lovering LOV3 Wave 20 100 0.3 0.3 0 08/05/13 Lovering LOV3 Wave 10 150 0.3 3.5 3.2
Date of Speed Distance T0 (A) T1 (B) Resuspension taking (miles / from sediments sediments Lake Site Period (mg L -1 ) samples h) shore (m) (mg L -1 ) (mg L -1 ) 08/05/13 Lovering LOV3 Normal 10 150 0.3 3.5 3.2 08/05/13 Lovering LOV3 Wave 30 100 0.3 0.3 0 08/05/13 Lovering LOV3 Normal 30 100 0.3 0.3 0 08/05/13 Lovering LOV3 Wave 30 200 0.3 0.3 0 08/05/13 Lovering LOV3 Normal 30 200 0.3 0.3 0 08/05/13 Lovering LOV3 Wave 20 200 0.3 1.5 1.2 08/05/13 Lovering LOV3 Normal 20 200 0.3 1.5 1.2 08/05/13 Lovering LOV3 Wave 20 150 0.3 0.3 0 08/05/13 Lovering LOV3 Normal 20 150 0.3 0.3 0 08/05/13 Lovering LOV3 Wave 10 100 0.3 1.5 1.2 08/05/13 Lovering LOV3 Normal 10 100 0.3 1.5 1.2 08/05/13 Lovering LOV3 Wave 30 100 0.3 0.3 0 08/05/13 Lovering LOV3 Normal 30 100 0.3 0.3 0 08/05/13 Lovering LOV3 Wave 10 200 0.3 0.3 0 08/05/13 Lovering LOV3 Normal 10 200 0.3 0.3 0 08/05/13 Lovering LOV3 Wave 10 200 0.3 0.3 0 08/05/13 Lovering LOV3 Normal 10 200 0.3 0.3 0 08/05/13 Lovering LOV3 Normal 20 100 0.3 -1.7 -2 08/05/13 Lovering LOV3 Wave 20 100 0.3 -1.7 -2 08/05/13 Lovering LOV3 Normal 20 200 0.3 0.3 0 08/05/13 Lovering LOV3 Wave 20 200 0.3 0.3 0 08/05/13 Lovering LOV3 Normal 10 150 0.3 1.5 1.2 08/05/13 Lovering LOV3 Wave 10 150 0.3 1.5 1.2 08/05/13 Memphremagog MEM1 Normal 30 200 1 2.2 1.2 08/05/13 Memphremagog MEM1 Wave 30 200 1 2.2 1.2 08/05/13 Memphremagog MEM1 Normal 10 200 1 1 0 08/05/13 Memphremagog MEM1 Wave 10 200 1 1 0 08/05/13 Memphremagog MEM1 Normal 20 150 1 1 0 08/05/13 Memphremagog MEM1 Wave 20 150 1 1 0 08/05/13 Memphremagog MEM1 Wave 30 100 1 1 0 08/05/13 Memphremagog MEM1 Normal 30 100 1 1 0 08/05/13 Memphremagog MEM1 Wave 10 150 1 1 0 08/05/13 Memphremagog MEM1 Normal 10 150 1 1 0 08/05/13 Memphremagog MEM1 Wave 10 100 1 4.2 3.2 08/05/13 Memphremagog MEM1 Normal 10 100 1 4.2 3.2 08/05/13 Memphremagog MEM1 Normal 10 150 1 1 0 08/05/13 Memphremagog MEM1 Wave 10 150 1 1 0 08/05/13 Memphremagog MEM1 Wave 10 200 1 1 0 08/05/13 Memphremagog MEM1 Normal 10 200 1 1 0 08/05/13 Memphremagog MEM1 Normal 20 200 1 1 0 08/05/13 Memphremagog MEM1 Wave 20 200 1 1 0 08/05/13 Memphremagog MEM1 Wave 30 100 1 1 0 08/05/13 Memphremagog MEM1 Normal 30 100 1 1 0 08/05/13 Memphremagog MEM1 Wave 20 150 1 1 0 08/05/13 Memphremagog MEM1 Normal 20 150 1 1 0
Date of Speed Distance T0 (A) T1 (B) Resuspension taking (miles / from sediments sediments Lake Site Period (mg L -1 ) samples h) shore (m) (mg L -1 ) (mg L -1 ) 08/05/13 Memphremagog MEM1 Wave 30 150 1 1 0 08/05/13 Memphremagog MEM1 Normal 30 150 1 1 0 08/05/13 Memphremagog MEM1 Normal 30 200 1 -0.2 -1.2 08/05/13 Memphremagog MEM1 Wave 30 200 1 -0.2 -1.2 08/05/13 Memphremagog MEM1 Normal 20 200 1 3 2 08/05/13 Memphremagog MEM1 Wave 20 200 1 3 2 08/05/13 Memphremagog MEM1 Normal 30 150 1 1 0 08/05/13 Memphremagog MEM1 Wave 30 150 1 1 0 08/05/13 Memphremagog MEM1 Normal 20 100 1 1 0 08/05/13 Memphremagog MEM1 Wave 20 100 1 1 0 08/05/13 Memphremagog MEM1 Wave 20 100 1 1 0 08/05/13 Memphremagog MEM1 Normal 20 100 1 1 0 08/05/13 Memphremagog MEM1 Wave 10 100 1 2.2 1.2 08/05/13 Memphremagog MEM1 Normal 10 100 1 2.2 1.2 08/05/13 Memphremagog MEM2 Normal 20 150 0.4 -0.8 -1.2 08/05/13 Memphremagog MEM2 Wave 20 150 0.4 -0.8 -1.2 08/05/13 Memphremagog MEM2 Normal 10 100 0.4 2.4 2 08/05/13 Memphremagog MEM2 Wave 10 100 0.4 2.4 2 08/05/13 Memphremagog MEM2 Wave 10 150 0.4 4 3.6 08/05/13 Memphremagog MEM2 Normal 10 150 0.4 4 3.6 08/05/13 Memphremagog MEM2 Wave 20 200 0.4 2.4 2 08/05/13 Memphremagog MEM2 Normal 20 200 0.4 2.4 2 08/05/13 Memphremagog MEM2 Normal 20 200 0.4 0.4 0 08/05/13 Memphremagog MEM2 Wave 20 200 0.4 0.4 0 08/05/13 Memphremagog MEM2 Normal 10 200 0.4 0.4 0 08/05/13 Memphremagog MEM2 Wave 10 200 0.4 0.4 0 08/05/13 Memphremagog MEM2 Normal 30 150 0.4 0.4 0 08/05/13 Memphremagog MEM2 Wave 30 150 0.4 0.4 0 08/05/13 Memphremagog MEM2 Normal 10 200 0.4 -0.8 -1.2 08/05/13 Memphremagog MEM2 Wave 10 200 0.4 -0.8 -1.2 08/05/13 Memphremagog MEM2 Normal 30 150 0.4 1.6 1.2 08/05/13 Memphremagog MEM2 Wave 30 150 0.4 1.6 1.2 08/05/13 Memphremagog MEM2 Normal 30 100 0.4 1.6 1.2 08/05/13 Memphremagog MEM2 Wave 30 100 0.4 1.6 1.2 08/05/13 Memphremagog MEM2 Normal 30 200 0.4 1.6 1.2 08/05/13 Memphremagog MEM2 Wave 30 200 0.4 1.6 1.2 08/05/13 Memphremagog MEM2 Wave 30 100 0.4 0.4 0 08/05/13 Memphremagog MEM2 Normal 30 100 0.4 0.4 0 08/05/13 Memphremagog MEM2 Wave 20 100 0.4 2 1.6 08/05/13 Memphremagog MEM2 Normal 20 100 0.4 2 1.6 08/05/13 Memphremagog MEM2 Wave 20 150 0.4 2.4 2 08/05/13 Memphremagog MEM2 Normal 20 150 0.4 2.4 2 08/05/13 Memphremagog MEM2 Normal 30 200 0.4 1.6 1.2 08/05/13 Memphremagog MEM2 Wave 30 200 0.4 1.6 1.2 08/05/13 Memphremagog MEM2 Normal 20 100 0.4 0.4 0
Distance T0 (A) T1 (B) Resuspensio Speed Date of taking samples from shore sediments (mg sediments n Lake Site Period (miles / h) (m) L -1 ) (mg L -1 ) (mg L -1 ) 08/05/13 Memphremagog MEM2 Wave 20 100 0.4 0.4 0 08/05/13 Memphremagog MEM2 Wave 10 100 0.4 4.4 4 08/05/13 Memphremagog MEM2 Normal 10 100 0.4 4.4 4 08/05/13 Memphremagog MEM2 Wave 10 150 0.4 3.2 2.8 08/05/13 Memphremagog MEM2 Normal 10 150 0.4 3.2 2.8 08/06/13 Memphremagog MEM 3 Wave 30 150 0.7 1.9 1.2 08/06/13 Memphremagog MEM 3 Normal 30 150 0.7 1.9 1.2 08/06/13 Memphremagog MEM 3 Normal 20 100 0.7 08/06/13 Memphremagog MEM 3 Wave 20 100 0.7 08/06/13 Memphremagog MEM 3 Wave 10 200 0.7 3.1 2.4 08/06/13 Memphremagog MEM 3 Normal 10 200 0.7 3.1 2.4 08/06/13 Memphremagog MEM 3 Normal 30 100 0.7 0.7 0 08/06/13 Memphremagog MEM 3 Wave 30 100 0.7 0.7 0 08/06/13 Memphremagog MEM 3 Normal 30 200 0.7 0.7 0 08/06/13 Memphremagog MEM 3 Wave 30 200 0.7 0.7 0 08/06/13 Memphremagog MEM 3 Normal 30 200 0.7 -0.9 -1.6 08/06/13 Memphremagog MEM 3 Wave 30 200 0.7 -0.9 -1.6 08/06/13 Memphremagog MEM 3 Normal 10 200 0.7 0.7 0 08/06/13 Memphremagog MEM 3 Wave 10 200 0.7 0.7 0 08/06/13 Memphremagog MEM 3 Normal 30 100 0.7 3.1 2.4 08/06/13 Memphremagog MEM 3 Wave 30 100 0.7 3.1 2.4 08/06/13 Memphremagog MEM 3 Normal 20 150 0.7 0.7 0 08/06/13 Memphremagog MEM 3 Wave 20 150 0.7 0.7 0 08/06/13 Memphremagog MEM 3 Normal 20 150 0.7 0.7 0 08/06/13 Memphremagog MEM 3 Wave 20 150 0.7 0.7 0 08/06/13 Memphremagog MEM 3 Normal 10 150 0.7 2.7 2 08/06/13 Memphremagog MEM 3 Wave 10 150 0.7 2.7 2 08/06/13 Memphremagog MEM 3 Normal 10 100 0.7 0.7 0 08/06/13 Memphremagog MEM 3 Wave 10 100 0.7 0.7 0 08/06/13 Memphremagog MEM 3 Normal 30 150 0.7 1.5 0.8 08/06/13 Memphremagog MEM 3 Wave 30 150 0.7 1.5 0.8 08/06/13 Memphremagog MEM 3 Normal 20 200 0.7 0.7 0 08/06/13 Memphremagog MEM 3 Wave 20 200 0.7 0.7 0 08/06/13 Memphremagog MEM 3 Normal 20 200 0.7 0.7 0 08/06/13 Memphremagog MEM 3 Wave 20 200 0.7 0.7 0 08/06/13 Memphremagog MEM 3 Wave 20 100 0.7 -1.7 -2.4 08/06/13 Memphremagog MEM 3 Normal 20 100 0.7 -1.7 -2.4 08/06/13 Memphremagog MEM 3 Normal 10 100 0.7 3.1 2.4 08/06/13 Memphremagog MEM 3 Wave 10 100 0.7 3.1 2.4 08/06/13 Memphremagog MEM 3 Normal 10 150 0.7 1.9 1.2 08/06/13 Memphremagog MEM 3 Wave 10 150 0.7 1.9 1.2 IMPACT OF THE NAVIGATION IN MILIEU LACUSTRE -
CAS OF AC MASSON AND THE AC OF SABLES
through
Sebastien Raymond, Ph.D.
Edited by Rosa
Galvez-Cloutier, Ph.D.,
Ing.Quebec City, November
252015 Institut National de la Recherche Scientifique Québec, Canada Join institution Table of materials
List of figures ...... 3 List of Tables ...... 3
1. Introduction ...... 5
2. Problem ...... 8
3. Study site...... 9
3.1...... Masson Lake Features...... 9
3.2...... Sand Lake Features...... 9
4. Methodology ...... 10
5. Results ...... 14
5.1 Lake Masson: from the laboratory to the field 14
5.2...... Sand Lake: Taking Action ...... 14
5.2.1...... Physical- chemical parameters ...... 14
5.2.2...... Wake Boat Pass Impacts and Generated Speeds ...... 15
5.2.3...... Changes in parameters at the bottom of Sand Lake ...... 19
6. Discussion ...... 22
6.1 Previous Impact Studies...... 22
6.2 Speeds generated at the bottom of Lake ...... 23
6.3...... Oxygenati on and phosphorus transfer? ...... 24
7. Conclusion and Outlook ...... 26 2 8. Thanks ...... 28
9. References ...... 29
3 Table of Figures
Figure 1: Photograph of the "WakeBoat" used for testing on Lake Masson ...... 6
Figure 2: Locations of test areas on Lake Masson based on bathymetric maps .. 10
Figure 3: Test Area Locations on Sand Lake based on bathymetric maps ...... 11
Figure 4: Photograph of equipment at the bottom of Lake ...... 1 2
Figure 5: 3D power measurements ...... 13
Figure 6: Profile of the physical-chemical parameters on the entire water column prior to the completion of the tests ...... 15
Figure 7: Average intensity (a) and speed generated (b) when the Wake Boat passes at different speeds for the 1 st day of testing ...... 16
Figure 8: Average intensity (a) and speed generated (b) when the Wake Boat passes at different speeds for the 2 nd day of testing ...... 18
Figure 9: Zoom of Figure 8a on the passages of boats in "Wake surf" mode for the 2nd day on Lake ...... of The Sands ...... 19
Figure 10: Time evolution of conductivity, dissolved oxygen and turbidity parameters at the bottom of Sand Lake for the 2 nd day of measurements ...... 20
Figure 11: View of the experimental device before (a) and 2 minutes after (b) the passage of a "Wake Boat" ...... 21
Figure 12: Speeds near sediments depending on boat speed 22
Figure 13: Abacus connecting the power of a boat and the maximum disturbance deep eur of particles of different sizes ...... 24
THEISTE OF TABLEAUX
Table 1: Masson Lake Morphometric and Hydrological Data ...... 9
Table 2: Sand Lake Morphometric and Hydrological Data...... 9
Table 3: Speed Measurement Scheme for a Test ...... 11 Terms of reference and legal limitations
The university and its staff have taken reasonable steps to carry out the research according to the rules of the art normally recognized in academic research, but offers no guarantee of results and does not guarantee any m applicants for the study that this work will lead to marketable or legally usable results. The university does not take responsibility for data-related consequences by either study applicants or third parties.
Reference to quote:
Raymond, S., and Galvez, R., Impact of Lake Navigation - Sediment Suspension Study: Lake Masson and Sand Lake Cases - 2015. Laval University. 30p. 1. INTRODUCTION
Quebec's lakes are resorts where people need to balance recreational activities, environmental protection and regulations. In particular, navigation on lakes is a federal jurisdiction (Coalition Navigation, 2014). In Canada, it is the Canada Shipping Act, and its related regulations, that regulate pleasure craft. By agreement between the federal government and the Quebec government, the Quebec Security service is responsible for enforcing this law. However, it is possible for municipalities to dictate regulations on the use of boats on the federal government's permission. It is possible to define an ethical code for protecting the environment of lakes. However, these "voluntary codes of conduct" require 100% user support. They often lead to difficult-to-resolve debates between the various stakeholders involved in communities across Canada (Coalition Navigation, 2014).
Studies have shown the impact of motorboats on lake ecosystems. Several factors affect the impact of a boat's passage such as the speed of navigation, the strength and type of engine, the geometry of the propeller, the geometry of the hull, the cohesion of the sediments, the size and mass of the particles forming sediments, water depth, lake stratification.
The popularity of wakeboats (Figure 1) among boaters is steadily increasing. The configuration of these boats can create substantial waves that allow enthusiasts to "surf" at the back of their boat. Figure 1: Photograph of the "WakeBoat" used for testing on Lake Masson
In 2014, Mercier-Blais and Prairie show that the waves produced by wakeboats must travel a distance of 300m or more on either side of the wake to dissipate the energy generated by it. completely resulting in sediment suspension and accelerated shoreline erosion. Wave action and turbulence as a result of shallow water navigation in lakes produce obvious sediment suspension and release of nutrients and pollutants into the water column (Alexander and Wigart, 2013 ; Bastien et al., 2009; Gélinas et al., 2005; Wang et al., 2009; Zoumis et al., 2001), as well as bacteria that are indicative of non- recent fecal contamination(Escherichia coli and total coliforms) (An et al., 2002) that have an impact on water quality. These processes are reinforced by the harvesting of macroalgae by helicopter and boat hulls (Lenzi et al., 2005, 2013).
Anthony and Downing (2003) tracked the effect of wind, boat traffic and turbidity on sediment resuspension and showed that higher wind speeds of 20 m.s -1 (45 mph) can mobilize up to 98% surface sediments and increase phosphorus concentrations (up 100%) ammonia (toxic levels) in the water column. The authors also observed that the correlation between boat traffic and sediment suspension was low, but that heavy boat traffic appears to exacerbate wind resuspension, which may slow the deposition of the suspended sediments. Lenzi et al. (2013) examined the amount and distances travelled by sediments and nutrients from boat disturbance. They showed that the mass of suspended material was relatively large, and that total phosphorus increased. Also, motorized recreational activities (motorboating, water skiing, jet skiing) can significantly increase pollution levels in lakes (metals, polycyclic aromatic hydrocarbons, etc.), which represents a high level of risk for aquatic organisms, particularly benthic invertebrates (Mosisch and Arthington, 2001). However, the influence of different types of boats, speeds and accelerations on sediment resuspension is poorly understood. In this context, the Department of Civil and Water Engineering at Laval University was asked by Isabelle and Mr. Dubitsky of the "Coalition for Sustainable and Responsible Navigation" (known as the "Navigation Coalition") to carry out proposed trials by Professor Y Prairie of the University of Montreal. Specifically, the tests involve the assessment of sediment resuspension and thus describe the impact of the passage of a "Wake boat" on the water column. 2. PROBLÉMATIQUE
In Quebec, the increase in water sports activities on lakes is a concern for citizens, associations, municipalities and residents concerned about the ecological impact that these recreational activities produce. The challenge lies in the inability to find sustainable environmental solutions that are satisfactory in terms of regulation. On the other hand, many question whether there is a causal link between the passage of motorized boats and the degradation of lake environments.
This project is therefore defined in order to provide preliminary scientific data with the ultimate goal for the Navigation Coalition to propose recommendations that will be proposed to the federal government in order to better regulate the use of boats on lakes.
The project seeks to assess the impact of wakeboat motorized boats. In order to broaden knowledge about the impact of navigation on lakes, including sediment resuspension, the study we propose aims to:
i) define the impact of the depth of the jets of the motorboat propulsion systems, ii) measure the generated speed that can resuspend sediments in the water column. 3. SITE STUDY
The study took place on two lakes in the Laurentian region (Quebec): Lake Masson(74- 02'05"O - 46-02'30"N) and Lac des Sables(74-18'08"O - 46-02'35"N).
3.1 Masson Lake Features Lake Masson is located in the MRC of The Countries of High at the level of the municipalities of Sainte-Marguerite-du-Lac Masson and Estérel. Masson Lake's morphometric and hydrological data are presented in Table 1. The Lake has a significant average depth of 11.3 m which will allow us to calibrate our protocol without environmental risk.
Table 1: Masson Lake Morphometric and Hydrological Data
Lake area 2,5 km² (618 acres) Volume of the lake 28 202 000 m³ (995944230.88 ft3) Maximum depth 47,3 m (155 ft) Average depth 11,3 m (37 ft) Altitude 335,3 m Watershed area including 34,9 km² (13.5 mi2) lakes Renewal time 1.41 years
3.2 Sand Lake Features The Sand lake is located in the MRC Les Laurentides at the level of the municipality of Saint-Agathe-des-monts. The morphometric and hydrological data from Sand lake are presented in Table 2. It has a slightly lower average depth of 7.1 m but has similar characteristics to Lake Masson.
Table 2: Sand Lake Morphometric and Hydrological Data
Lake area 2,96 km² (731 ac.) Volume of the lake 21 105 000 m³ (745316041 ft3 Maximum depth 23.6 m (77.4 ft) Average depth 7.1 m (23.3 ft) Altitude 376.6 m 2 Watershed area including lakes 38.8 km² (15 mi )
Renewal time 0.95 year 4. MÉTHODOLOGIE
To measure the impact of lake navigation, the speed and depth impacted by wake boat passage were measured: Five speeds were tested: 5 km/h (~3mph); 10 km/h (~6mph); Maximum speed: 50 to 70 km/h(from 33 to 44 mph). Wave Surf's speed: 19 km/h (up 12 mph) Wake Boat's speed: 29 km/h (up 18 mph)
At least two depths have been tested by lake, approximately 15 meters (50 ft) and meters 9 (30 ft) on Lake Masson and about 6 (20 ft) and 5 meters (16 ft) for Sand Lake. The data acquisition points are visible on the bathymetric maps of Masson Lake and Sand Lake shown in Figure 2 and Figure 3, respectively.
Test area
Figure 2: Locations of test areas on Lake Masson based on bathymetric maps(http://www.crelaurentides.org/dossiers/eau-lacs/atlasdeslacs?lac=12214) Test area
Figure 3: Locations of Test Areas on Sand Lake based on bathymetric maps(http://www.crelaurentides.org/dossiers/eau-lacs/atlasdeslacs?lac=12138)
This data will assess a critical depth of impact of the Wake Boat. Depending on the velocity generated in the water column, it is at this critical depth that the bottom sediments will potentially be suspended. All trials will be conducted in triplicate to obtain representative data as summarized in Table 3.
Table 3: Speed Measurement Scheme for a Test
Speeds Depth (m) Number of (km/h) Type of boat passes per experience . 5 (3.1 mph) . 10 (6.2 mph) . 10 (32.8 ft) . max. (33-44 mph) . 20 (65.9 ft) . Wake boat 3 . Wave surf speed (up to 12 mph) times . Wake boat speed (up 18 mph) The tests were carried out during the months of August to September, a temperature profile was carried out to find out if there is stratification of the lakes.
The fieldwork included the installation of an ADCP (Acoustic Doppler Current Profiler) which defines itself as (Figure 4):
Acoustic - Using a sound wave; Doppler - Doppler effect applied to speed measurement. The Doppler effect allows you to make very high-frequency sounds and by listening to echoes returned by reflectors in the water. Current - Measuring water speed; Profiler - Measuring a speed profile, not a point speed.
Figure 4:Photograph of equipment at the bottom of the lake
Following the recording of the data, work was done to extract and exploit the data stored in the ADCP for determining the speed of the current and the intensity of the disturbance.
The ADCP is an instrument that calculates the components of water velocity at different depths in the water column, in all 3 directions (Figure 5). The equipment allows you to calculate the speed and direction of the current for the entire water column. The velocity is determined by cells (the water column is cut into vertical elements) whose size and number can be adjusted. A multi-cell vertical is called together. The Doppler effect allows
A n Z d x sounds to be transmitted at fixed frequencies and listening to the echoes returned by the reflectors in the water. These reflectors are small microscopic particles of sediment or plankton naturally present in the water, which move at a speed equal to the water and reflect the sound towards ADCP (Figure 5). The ADCPs selected for the tests have 4 transducers that emit acoustic pulses at frequencies in the order of 1.2 MHz. These pulses are returned and more or less distorted by particles (reflectors) in suspension in the water according to their speeds. The distance between the particle (reflector) and the ADCP is calculated based on the time between the emission and the receipt of the pulse (Lane et al., 1999; RD Instruments, 1989). Although the speed of the sound with the density of the medium along acoustic paths, the preservation of the horizontal component of the number of waves allows to determine horizontal velocity from the knowledge of the speed of sound at the transducer level only. Using the Doppler effect, the system calculates the water speed in three dimensions (2 horizontal and 1 vertical) to the right of each beam (3 or 4 beams) by using trigonometric rules.
Figure 5: 3D Yard Measures (RD Instrument, 1989)
Acoustic technologies are non-intrusive and have the advantage of providing information simultaneously and in the same place on the topography of the bottom, the speed field (Thorne et al., 2002). 5. RÉSULTS
The results will be presented by lake to differentiate the two field campaigns and focus on the interests of each.
5.1 Lake Masson: from the laboratory to the field
Lake Masson was the first lake to participate in this type of research. It was a major element in the development of the instrumentation implementation protocol. Indeed, the only tests carried out took place in the laboratory with controlled conditions both in the calibration of the device and in the implementation of the instrumentation. However, natural trials are often different and much more difficult than those in the laboratory, and these tests have only confirmed the adage.
Nevertheless, the trials on Lake Masson were essential to understand the dysfunctional elements of the protocol. Difficulties in calibrating the device appeared on the boat as well as difficulties in setting up the instrumentation related to the winds and the complexity of the device.
Following the two tests carried out, we were able to optimize the device and we also improved the implementation of the instrumentation by simplifying the device. In the end, it was faster and safer.
5.2 Sand Lake: Taking action
Once the protocol was optimized, the first measurements were taken on Sand Lake.
5.2.1Physical-chemical parameters
Figure 6 shows the temperature, turbidity and dissolved oxygen profiles in the water column for the 2nd day of water measurements on Sand Lake. The results of the two days of measurements are similar. 0 20 40 60 80 100 120 0 0,5 1 Temp (C°) 1,5 ODsat 2 (%) 2,5 Turbid 3
3,5 NNNT 4 U(NTU N 4,5 NTU 5 )
Figure 6: Profile of the physical-chemical parameters on the entire water column before the tests are carried out NTU = nephelometric turbidity units
The values are also similar to those measured in 2006 by the Laurentian Regional Environment Council (CRE Laurentides). In their work, it appears that the lake is laminated during the summer for depth values ranging between 7m and 9m. Our tests were conducted in shallow waters, so there is no apparent stratification at this depth. It should be noted that in the case of this study, it is not so much the value of these parameters that is interesting but their variations if necessary, during a passage from "Wake Boat".
The tests were therefore conducted in good conditions because there was no impact of the stratification.
5.2.2Wake Boat Impacts and Generated Speeds
Figures 7 and 8 present the results of the test days on Sand Lake for the 1st and 2nd day respectively. This distinguishes the results of the average intensity in the number of strokes (Figure 7a and 8a) that characterizes the intensity of the disturbance and goes so to respond to the depth of impact. Figures 7b and 8b will indicate the speeds generated by the Wake Boat passage. h h h p / / m m m 3 k k
h h h ) / 9 9 / f p r 2 1 m ) m u m k k d
S
r m
3
0 a e 5 h 1 o k / a B m k e W
( k 5 a (number of W ( hits)
a)
(mm/s)
b)
Figure 7: Average intensity (a) and speed generated (b) when the Wake Boat passes at different speeds for the 1st day of testing 5km/hr = 3mph; 10km/hr = 6mph; 19km/hr = 12mph; 29km/hr = 18mph ; 53km/hr = 33mph.
The number of moves allows us to define the intensity of the disturbance, it corresponds to the number of pulses received for the device. The larger the number of strokes, the more reflectors there are in the water, so the greater the number of pulses received by the ADCP. Figure 5a shows that each passage from "Wakeboat" to an impact on the water column. At 5 km/h (3 mph) and at 53 km/h (33 mph) the impacts on the water column do not exceed the meter deep. For speeds of 10 km/h (6 mph) and/or in Wake Board mode ( 29 km/h) (18 mph) the impacted depth is about 2.5m (8 ft).The impact The more important is The fashion Wake Surf (19 km/h) (12 mph) which is measured up to 4.5m (15 ft.). Figure 7b shows the depths at which speeds of at least 0.1 m/s (0.33 ft/sec) are generated in the water column by passing boats. The correlation with figure 7a is obvious. Boat crossings at low (5 km/h) or high speeds (50 km/h) generate speeds of at least 0.1 m/s (0.33 ft/sec) up to about 1 m (3 ft) deep. For boat crossings at 10 km/h (6mph) and in "Wake Boat" and Wake Surf use, speeds of 0.1 m/s (0.33 ft/sec) are generated in the water column up to about 4.5m (15 ft):
2m (6.5 ft.) for 10km/h 2.5m (8.2 ft.) for the Wake Board 3m (10 ft.)for Wake Surfing
Figures 8a and 8b represent the same indicators as Figures 7a and 7b for the 2nd day respectively. The impacts are similar, but they appear clearer and more pronounced. Indeed, the adjustments made on the 2nd day in terms of navigational conditions were optimal: the rear ballasts were filled and there were 3 people in the Wake Boat to add weight. This made it more like reality because these boats are remembered as a party place where it is not uncommon to have more than six or seven people on board. The most impactful passages on the water column are clearly during the wake surf and Wake Board mode. The depth of impact can exceed 4.5 meters (15 ft) in this case.
The first peaks that appear are due to the passage over our instrumentation of a pontoon (100HP) at a speed of 15 km/h (9 mph). Even if this is not the purpose of the study, one can notice for this type of motorized boat, an impact depth of up to 2.20m. (7 ft)
The passages of boats in use "Wake surf" and "Wake Board" generates speeds in the water column of 0.1 m/s up to 4.5m and 4m respectively. It is therefore potentially possible for these vessels to resuspend sediments of 50 μm up to 4.2 (14 ft) to 5m (16 ft.) deep. Indeed, the peaks go down to a depth of 4.5m (15 ft) but there is a 'blind' zone due to the resonance of the transmitter (RDI, 1996) of about 20cm (0.7 ft) to 30cm (1ft) above the ADCP as well as the size of the device which is about 40cm. It is therefore reasonable to assume that speeds of 0.1m/s (.33 ft/sec) can be generated up to 5m (16 ft). Unlike day one, the ballasts were filled for wake board passages. We can see the difference and the importance of this factor in the depth impacted. Indeed, with full ballasts the impact is much greater: 4m (13ft) instead of 2 (7 ft) to 3m (10 ft). The maximum speed generated in the water column reaches values of 0.6 m/s to 0.7 m/s (2 – 2.3 ft/sec) when the boat goes into Wake surf mode. There is therefore a low impact (about 1m) (0.6 ft) for low or high boat speeds and a strong impact (up to 4.5m (16 ft.) to 5m (16 ft)) for intermediate boat speeds. h ) / f r m u ) k h
/ h d S / r
9 m ) a e 1 m k k n o
k
a o 9 B t
5 2 W n e 1 ( k o a
P ( h W / ( m k
5
(name of blows)
a)
(mm/s)
b ) Figure 8: Average intensity (a) and speed generated (b) when the Wake Boat passes at different speeds for the2nd day of testing It is also important to know the duration of this impact in the water column. Figure 9 measures the duration for the wake surf for the 2nd day. Each is framed in black and measures between 72 and 80 seconds. We can clearly see in the3rd passage the movement of the disturbance in the water column and in the time.
The individual impact of each pass is therefore well marked and lasts a few minutes.
1he Passage 2nd passage 3rd passage
Number of hits
Time (seconds)
Figure 9: Zoom of Figure 8a on the passages of boats in Wake surf mode for the 2nd day on The Sand Lake
5.2.3 Changes in parameters at the bottom of Sand Lake
Using multiparametric probes, turbidity (Figure 10a), conductivity (Figure 10b) and dissolved oxygen (Figure 10c) parameters were measured at the bottom of Sand Lake during boat crossings. Figure 10 thus shows the complement of these three parameters in time for the 2nd day of measurements on Sand Lake. This day is selected because it is the one whose impact on the water column is most marked. The absolute values of the parameters are less important to us here than their variations. However, there is no significant variation in these parameters, despite the fact that speeds of 0.1 m/s are generated at these depths. Turbid (NTU) 7
6.8
6.6
6.4
6.2
6
a) 5.8 09:50:24 09:57:36 10:04:48 10:12:00 10:19:12 10:26:24 10:33:36 10:40:48 10:48:00 10:55:12
Cond (mS/cm) 0.0682
0.068
0.0678
0.0676
0.0674
0.0672
0.067
b) 0.0668 09:50:24 09:57:36 10:04:48 10:12:00 10:19:12 10:26:24 10:33:36 10:40:48 10:48:00 10:55:12
93 FROM Sat (%) 92 91 90 89 88 87 86 c) 85
09:50:24 09:57:36 1 0:04:48 10:12:00 10:19:12 10:26:24 10:33:36 10:40:48 10:48:00 10:55:12
Figure 10: Time evolution of conductivity, dissolved oxygen and turbidity parameters at the bottom of Sand Lake for the 2nd day of measurements This was confirmed by the observations of the diver visible in Figure 11. He did not notice any material suspended as a result of the passage of the boats. The most plausible hypothesis is that the granulometry of the bottom sediments is mostly greater than 50μm in this part of the lake and therefore requires speeds greater than 0.1 m/s to resuspend sediments in the water. a) b)
Figure 11: View of the experimental device before (a) and 2 minutes after (b) the passage of a "Wake Boat" 6. DISCUSSION
It is important to compare the results obtained with those obtained by other researchers in previous studies.
6.1 Previous impact studies
Using other methodologies and/or technologies, several authors have measured the impact of motorboats. These boats have strengths of up to 150 HP. They measure a release of phosphorus for depths of 1.5 to 3.4 m (5–11 ft.) (Youssef, 1980) and estimates that boats are responsible for at least 17% of total phosphorus intakes during the summer season (James et al, 2002). Anthony and Downing (2003) observe an increase in turbidity for lake depths ranging from 127 to 188 cm (4 – 6 ft). They estimate that low-speed vessels and high-speed vessels do not induce deep water movement compared to intermediate speeds as shown in Figure 12. The results even indicated that a speed of 30 mph (48 km/h) had less impact than a speed of 3 mph (5km/h).
Figure 12: Speeds near sediments based on boat speed after Anthony and Downing
(2003)
These studies are in line with our results with respect to impacts at low and high pass speeds. The depths measured are lower than those of this study, but the vessels used at the time did not have150HP. They also did not have the technologies to measure disturbances in real time. Some studies have found that outboard engines have more impacts than intermediate- lived internal engines, and vice versa at high speeds. But in general, the three types of engines (outboard, in-house and marine motorbike) caused water to move near the similar bottom (Anthony and Downing, 2003). These conclusions are to be qualified because the depths of the tests are very small (less than 2 meters). In view of our results and in view of the evolution of the boats over the last 15 years, it is reasonable to think that the different types of engines will impact the lake differently in terms of depth and speed. There was no stratification of the lake at the depths tested, but it could limit the impact of boats on sediments by its resistance to mixing (James et al., 2002).
6.2 Speeds generated at the bottom of the lake
Sediment suspension is correlated with depth speed, low at low or high boat traffic speeds, and maximum at intermediate speeds. Beachler (2002) theoretically indicates, and observations confirm, that the rate of movement of a 0.3 mm (0.01 in) sand particle is about 25 cm/s (.8 ft/sec) while a clay particle of 50 μm requires a water velocity of 12 cm/s (0.4 ft/sec). A particle of 2 μm requires a speed of 2.5 cm/s (0.08 ft/sec).
The results show that this can be achieved when the Wake Boat is in Wake Surf, about 12 mph (19 km/h).
Several models have been developed linking depth, engine strength and particle size (Figure 13). However, this work stops at a power of 200HP which prevents the results from being correlated but offers interesting prospects for future research. However, they confirm that the higher the power of the boat, the greater the speed of this study using much more powerful boats, so it makes sense that the impacts obtained reach depths not yet observed, namely 5 m. Figure 13: Calculations (graph?) produced by Youssef (1978) linking the power of a boat (HP) and the maximum disturbance depth of particles of different sizes according to Beachler (2002).
It is important to mention that if the speed of movement is reached near the bottom, this does not involve the suspension of the particle. The speed of movement must indeed be higher than the rate of sedimentation described by Stokes Law.
6.3 Oxygenation and phosphorus transfer?
One comment that comes up regularly by wake boat users concerns the oxygenation of 4 the bottom of the lake. Repeated "Wake Boat" passages would thus be useful and beneficial to the health of the lake by introducing oxygen into the water column. This theory is obviously wrong. Bottom sediments are often phosphorus reservoirs in lakes, when boating, if suspended then the boats could even contribute significantly to the transfer of phosphorus into the water column. In oxic condition, a parameter that seems 3- important in the release of PO4 is pH. The higher (basic) it is, the higher the release of 3- PO4 (James et al 2002). Similarly, the temperature appears to be aborting the release of phosphorus, suggesting the dominance of biological processes under oxygen-rich conditions. In oxic condition, brewing would therefore be favorable to the lay-off of the PO 3- contained in the sediments. This allows us to consider scenarios that could be harmful to the health of the lakes. It could be said that several Quebec lakes meet the following adverse conditions:
Passage of many Wake Boat boats Phosphorus-rich sediments Low depth so no stratification and rich in oxygen on the whole water column or introduced by the "Wake Boat" pH due to the presence of microphyll with ears (Raymond and Galvez, 2014) High temperature
All of these conditions promote the release of phosphorus under oxic conditions and thus promote the phenomenon of eutrophication or accelerated aging of the lake. 7. CONCLUSION AND PERSPECTIVES
Boating on Quebec's lakes is constantly increasing. Wake Surfing practices and the power of boat engines continue to grow. These practices have a significant impact on the water column and would increase water turbidity, total phosphorus and orthophosphate concentration, dissolved oxygen near the bottom and thus the potential for oxydo-reduction and would reduce the sediment consolidation. Total phosphorus release and especially orthophosphate may be a factor in premature aging of lakes called eutrophication. This increase in phosphorus in the water column can also promote the development of cyanobacteria (Blue-Green Algae), which is becoming a major problem in many Quebec lakes.
The objective of this study was to assess the impacts in the water column by Wake Boat, which are motorized boats with a power of more than 350 hp. These impacts were measured here for the first time using ADCP technology. This tool can determine the depth and speeds generated by the passage of boats in real time. The innovative nature of the study therefore depends as much on the nature of the boats and practices tested as on the technology used to quantify impacts. The questions that can be answered relate to the depth of the impact and the velocity generated in the water column.
In terms of depth, the results show that at low and high boat speeds (5 km/h (3 mph), 10 km/h (6 mph) and maximum speed), there is a limited impact on the water column not exceeding 1 to 2m (3-6 ft) deep. Wake surfing and wake board practices impact the water column up to 5 m (16 ft). No study has yet quantified an impact of this magnitude on the lakes. This disturbance has also been quantified over time, allowing to determine a duration going to vary between 70 and 80 seconds.
For speeds, speeds are greater than 0.1 m/s (.3 ft/sec) up to 5m (16 ft) for wake surfing and 4m (13 ft) for wake board. These velocities are theoretically capable of carrying particles 50 µm in diameter. Under the conditions studied, the wake surf/Wake board has the potential to impact the water column and remobilize bottom sediments up to 5m for more than a minute.
These results are to be compared with those held by Mercier-Blais and Prairie in 2014 who evaluated that during the "Wake surf" and "Wake board" practices, the surface wave created needed at least 300m to lose its energy and no longer erode the banks.
Thus, for a responsible and sustainable navigation it is necessary to prevent the impact of boats on shoreline erosion, on the suspension of sediments, and thus the availability of phosphorus in the water column. It is therefore necessary to advocate a practice of Wake Surf and Wake Board (with 350HP boats) in areas 600m wide and at least 5m deep. If one of these conditions is not met, then these navigation practices must be limited/framed as they impact the environment. Other recreational boating practices should also be monitored with speeds of no more than 5km/h in areas below 2m deep and 10km/h in 2 to 5m zones.
The study here is limited to the Wake Boat, which is required to have a full range of impacts, other types of motorized craft will need to be considered and studied. The same tests can be done with all types of boats (motorized or not) and this on the water column as well as on the lateral impact of surface and banks. This would allow for a clear and complete view of the impacts and would recommend lake navigation conditions that would have little or no impact.
In order to complete this, it would also be interesting to take into account the traffic on the lake. It has been determined here that a "Wake Boat" passage alone has an impact over a period of more than one minute, but what happens if another passage takes place in the same area and in the same minute? Is there a cumulative effect of the passages and therefore an even greater depth of impact? This would involve different sailing conditions, should we increase the depth even further, train the drivers not to pass in the same places, limit the maximum number of boats on the lake?
This study is an important first step in understanding the impacts of motorized boats enabling responsible and sustainable navigation. However, there are still many elements and conditions to be explored in order to have a complete picture of the types of practices, ridership on lakes in Quebec and Canada, and impacts on water quality and shoreline erosion.
8. REMERCIEMENTS This pioneering project has benefited from the financial support of more and more sponsors whom we would like to thank:
Lac-Masson in Estérel and Ste-Marguerite-du-Lac-Masson - MRC of the High Countries - Municipality of Estérel and its mayor Jean Pierre Neveu - Municipality of Ste-Marguerite-du-Lac-Masson and its mayor Gilles Boucher
Lac-des-Sables in Ste-Agathe-des-Monts - City of Ste-Agathe-des-Monts - The Landing Committee, of the Association for the Protection of the Environment of Sand lake
A special mention to all the volunteers who kindly donated their time, their materials and who allowed the realization of this study: - Roger Martel (membersof the Estérel CityCouncil) - Christine Corriveau (members of estérel City Council) - Luc Lafontaine (Ceo of the City of Estérel) - Daniel Piché - Maxime Piché - Marc Legault - Gilles Morin
We also thank Mr Jean-Pierre Dumoulin of Xplorations Without Limits who dived to allow the proper installation of the instrumentation as well as for the sharing of this knowledge and his sympathy. 9. RÉFÉRENCES
Alexander, M.T., Wigart, R.C., 2013. Effect of motorized watercraft on summer nearshore turbidity at Lake Tahoe, California–Nevada. Lake and Reservoir Management 29, 247–256.
An, Y.J., Kampbell, D.H., Peter Breidenbach, G., 2002. Escherichia coli and total coliforms in water and sediments at lake marinas. Environmental Pollution 120, 771– 778.
Anthony, J., et J. Downing. 2003. Physical impacts of wind and boat traffic on Clear Lake, Iowa, USA. Lake and Reservoir Management 19: 1-14.
Bastien, D., Demers,A., Named P., L., Rancourt, E., 2009. Environmental experts. Final mandate report. Environmental impacts of motorized boats and water sports on Lake Massawippi. 123pp.
Beachler, M. M. 2002. The hydrodynamical impacts of recreational watercraft on shallow lakes, p. 77. Master thesis. Department of civil and environmental engineering. Pennsylvania State University. 74 p.
Coalition Navigation, 2014. Highlights: Coalition Vision.Published October 22, 2014. Available online: http://coalitionnavigation.ca/fr/.
CRE Laurentides, 2006. Physicochemical report, Sand Lake , Summer 2006.
Gélinas, R., Bouchard Valentine, M., Roy., M-S., 2005. Impacts of motorized boats on the release of phosphorus from sediments: literature review and analysis for Lake St. Augustine. Ville de Québec - Environment Department.46pp.
James, W., J. Barko, H. Eakin, et P. Sorge. 2002. Phosphorus budget and management strategies for an urban Wisconsin lake. Lake and Reservoir Management 18: 149 - 163.
Lane, A., Knight, P.J., Player, R.J., 1999. Current measurement technology for near ‐shore waters. Coastal Engineering 37, 343–368.
Lenzi, M., Finoia, M.G., Gennaro, P., Mercatali, I., Persia, E., Solari, J., Porrello, S., 2013. Assessment of resuspended matter and redistribution of macronutrient elements produced by boat disturbance in a eutrophic lagoon. Journal of Environmental Management 123, 8–13. Lenzi, M., Finoia, M.G., Persia, E., Comandi, S., Gargiulo, V., Solari, D., Gennaro, P., Porrello, S., 2005. Biogeochemical effects of disturbance in shallow water sediment by macroalgae harvesting boats. Marine Pollution Bulletin 50, 512–519.
Mercier-Blais, S., Prairie, Y., 2014. Project to assess the impact of waves created by wakeboat boats on the shores of Lakes Memphremagog and Lovering. 41pp.
Mosisch, T.D., Arthington, A.H., 2001. Polycyclic aromatic hydrocarbon residues in the sediments of a dune lake as a result of power boating. Lakes and Reservoirs: Research and Management 6, 21–32.
Raymond, S., Galvez, R., 2014. Environmental diagnosis of Lake Sergeant: characterization of sediments andsurface water qualite - 2014. Laval University.45pp.
RD Instruments, 1989. Acoustic Doppler current profilers. Principles of operation: a practical primer.39 p.
RD Instruments, 1996. Acoustic Doppler current profilers. Principles of operation: a practical primer. San Diego CA.
Thorne P.D., Hanes, D.M., 2002. A review of acoustic measurement of small-scale sediment processes. Continental Shelf Research, 22 (4), 603–632.
Wang, S., Jin, X., Zhao, H., Wu, F., 2009. Phosphorus release characteristics of different trophic lake sediments under simulative disturbing conditions. Journal of Hazardous Materials 161, 1551–1559.
Youssef, Y. A., W. M. MCLellon, et H. H. Zebuth. 1980. Changes in phosphorus concentrations due to mixing by motor-boats in shallow lakes, p. 841-852, Water Research.
Zoumis, T., Schmidt, A., Grigorova, L., Calmano, W., 2001. Contaminants in sediments: remobilisation and demobilisation. Science of the Total Environment 266, 195–202. Scott Watershed Management Organization 200 Fourth Avenue West Shakopee, MN 55379-1220 952-496-8054 Fax 952-496-8496 www.scottcountymn.gov/wmo
May 19, 2021
To: Watershed Planning Commission
From: Megan Tasca, P.E., Water Resources Engineer
RE: Scott County MS4 Annual Meeting for Public Comments on Stormwater Pollution Prevention Plan
As an annual requirement of the National Pollutant Discharge Elimination System (NPDES) General Storm Water Permit for Small Municipal Separate Storm Sewer Systems (MS4s), Scott County must receive public comment and opinion on the adequacy of their Storm Water Pollution Prevention Programs. This public meeting is offered to solicit that input and to provide the public with an opportunity to participate in the development and implementation of the program. Staff is looking for consideration and comments from the WPC to the Board.
Scott Watershed Management Organization 200 Fourth Avenue West Shakopee, MN 55379-1220 952-496-8054 Fax 952-496-8496 www.co.scott.mn.us
Memorandum
May 24, 2021
To: Watershed Planning Commission
From: Ryan Holzer, Water Resources Scientist
Subject: Kevin Koepp Grade Stabilization Application
Included with this memo is an application to a WMO cost share application for Kevin Koepp for a grade stabilization structure project. The property is in Scott County in T113N, R25W, Section 16, Blakeley Township.
A grade stabilization structure was constructed in 1966 at this location. A corrugated metal pipe is experiencing erosion within the structure and thus is in imminent danger of failing. Repairs are eligible for cost share per our docket if they are not currently under contract, which this project is not. A repair now is likely to cost less than if the structure fails and a whole new structure would need to be installed at a later date.
This project would prevent sediment and nutrients entering the Minnesota River that would be caused by future erosion without the structure functioning properly. The estimated cost for the project is $21,560.00. The proposed amounts are $12,936.00 from the WMO and $8,264.00 from the landowner. There are enough funds in the 2021 WMO Local General Fund (LGF) to cover the costs for this project. This project was on the waiting list for funding since 2020 and with several new grants becoming available this has freed up LGF for projects that are not eligible for those grants.
This project has an estimated sediment reduction that does not require a Screening Committee recommendation. However, this project is unique in the fact that the erosion is an estimation of what is likely to occur if the structure fails instead of most projects which the erosion is currently present. For that reason, the variability on the reduction estimate numbers could fluctuate more for this project than more typical projects that are reviewed and thus we felt as though going this extra step in the review process was pertinent. The Scott SWCD Screening Committee reviewed the application at their May 18th Board Meeting and recommended approval.
Kevin Koepp Grade Stabilization Structure
Cooperator & Location Map of Project Site Name Kevin Koepp Address 817 Farmers Way City/Twp Blakeley Watershed SWMO
Project Details Practice Grade Stabilization Structure Quantity 1.00 Each Project ID SR-19-159 Project Term 10 year(s) Resource Protected Intermittent Stream
Overview
Landowner Kevin Koepp has taken steps to reduce soil erosion entering the ravines on his rented property by installing filter Current Project Site strips and maintaining an existing Grade Stabilization Structure (GSS constructed in 1966). The GSS is failing due to corrosion of the pipe. Water has started to undermine the soil under the pipe and is causing slumping of the earthern berm. Landowner has tried to fix what he can but we are in agreement the structure will continue to fail and eventually cause both erosion of the GSS berm and erosion head-cutting within the ravine. A new GSS was designed based on current NRCS specs and is similar to the 1966 GSS.
Total Cost Sources Cooperator: $8,624.00 SWMO: $12,936.00 $21,560.00 SWCD: $0.00
Federal: $0.00
Environmental Benefits Unit Costs* Local Funding Partner Parameter Before After Saved Sed Phos Runoff Soil Erosion (tons/yr) 13.7 0.0 13.7 $/Ton $/Pound $/Ac Ft Sediment (tons/yr) 13.70 0.00 13.70 SWCD: $0.00 $0.00 $0.00 Phosphorus (lbs/yr) 13.70 0.00 13.70 SWMO: $94.42 $94.42 $0.00 Runoff Volume (acre ft) 0.00 Overall: $157.37 $157.37 $0.00
*Over term of cost share contract
For more information contact Scott SWCD at 952.492.5425 or visit scottswcd.org
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