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HomeMy WebLinkAbout05/10/2016LAUDERDALE CITY COUNCIL MEETING AGENDA 7:30 P.M. TUESDAY, MAY 10, 2016 LAUDERDALE CITY HALL, 1891 WALNUT STREET The City Council is meeting as a legislative body to conduct the business of the City according to Robert's Rules of Order and the Standing Rules of Order and Business of the City Council. Unless so ordered by the Mayor, citizen participation is limited to the times indicated and always within the prescribed rules of conduct for public input at meetings. 1. CALL THE MEETING TO ORDER 2. ROLL CALL 3. APPROVALS a. Agenda b. Minutes of the April 26, 2016 City Council Meeting c. Claims Totaling $104,441.32 4. CONSENT a. Non-union Staff Compensation 5. SPECIAL ORDER OF BUSINESS/RECOGNITIONS/PROCLAMATIONS 6. INFORMATIONAL PRESENTATIONS / REPORTS a. City-wide Garage Sale 7. PUBLIC HEARINGS Public hearings are conducted so that the public affected by a proposal may have input into the decision. During hearings all affected residents will be given an opportunity to speak pursuant to the Robert's Rules of Order and the standing rules of order and business of the City Council. 8. DISCUSSION / ACTION ITEMS a. Resolution 051016A in Recognition of Peace Officers Week 9. ITEMS REMOVED FROM THE CONSENT AGENDA ITOW.11 13 11" [INKIM "MUTM 11. SET AGENDA FOR NEXT MEETING a. Comprehensive Plan RFP b. Nuisance Ordinance Updates c. Use of Chemicals Policy d. Annual Storm Water Report 12. WORK SESSION a. Opportunity for the Public to Address the City Council Any member of the public may speak at this time on any item not on the agenda. In consideration for the public attending the meeting, this portion of the meeting will be limited to fifteen (15) minutes. Individuals are requested to limit their comments to four (4) minutes or less. If the majority of the Council determines that additional time on a specific issue is warranted, then discussion on that issue shall be continued at the end of the agenda. Before addressing the City Council, members of the public are asked to step up to the microphone, give their name, address, and state the subject to be discussed. All remarks shall be addressed to the Council as a whole and not to any member thereof. No person other than members of the Council and the person having the floor shall be permitted to enter any discussion without permission of the presiding officer. Your participation, as prescribed by the Robert's Rules of Order and the standing rules of order and business of the City Council, is welcomed and your cooperation is greatly appreciated. b. Proposed Use of 2520 Larpenteur Avenue by ChowGirls Killer Catering c. Storm Water Project Discussion with Capitol Regions Watershed District d. Community Development Update LAUDERDALE CITY COUNCIL MEETING MINUTES Lauderdale City Hall 1891 Walnut Street Lauderdale, MN 55113 Page 1 of 3 April 26, 2016 Mayor Dains called the Regular City Council meeting to order at 7:30 p.m. Councilors present: Mayor Jeff Dains, Mary Gaasch, Roxanne Grove and Lara Mac Lean. Councilors absent: Denise Hawkinson. Staff present: Heather Butkowski, City Administrator and Jim Bownik, Assistant City Administrator. Approvals Mayor Dains asked for changes to the meeting agenda. There being none, motion was made by Councilor Grove to approve the agenda, seconded by Councilor Mac Lean and carried unanimously. Councilor Gaasch moved to approve the City Council meeting minutes of April 12, 2016. Councilor Grove seconded the motion and carried unanimously. Councilor Gaasch moved and seconded by Councilor Mac Lean to approve the claims totaling $21,832.33. Motion carried unanimously. Consent Mayor Dains asked if any Councilors wished to remove items from the Consent Agenda. There being none, Councilor Mac Lean moved and seconded by Councilor Grove to approve the Consent Agenda thereby approving March Financial Report, Utility Billing Correction Policy and First Quarter Investment Report. Motion carried unanimously. Public Hearing A. Predatory Offender Ordinance Mayor Dains introduced the proposed predatory offender ordinance highlighting the main issue of distance. City Administrator Butkowski explained the correct maps that were included in the council packets showing distances of 1,000 feet, 1,500 feet and 2,000 feet from city parks and daycare centers. The ordinance has been drafted with 2,000 feet per the last council discussion. Mayor Dains opened the public hearing at 7:36 p.m. There being no public comment, Mayor Dains closed the public hearing at 7:37 p.m. Motion was made by Councilor Gaasch to adopt Ordinance No. 16-02 adding Title 5, Chapter 11 to the Code of Ordinances regarding Predatory Offenders, seconded by Grove. Motion carried unanimously on a roll call vote. LAUDERDALE CITY COUNCIL MEETING MINUTES Lauderdale City Hall 1891 Walnut Street Lauderdale, MN 55113 Page 2 of 3 April 26, 2016 Discussion / Action Items A. Resolution 042616A in Support of the Start by Believing Community Initiative Mayor Dains explained that the Start by Believing campaign is a community initiative in Ramsey County approved by the county commissioners by resolution. City Administrator Butkowski further explained that the campaign is to improve the response to victims of sexual violence. Cities are asked to adopt a resolution in support. Motion was made by Mac Lean and seconded by Grove to approve Resolution 042616A Supporting Ramsey County in its Efforts to Eliminate Sexual Violence and Harm in our Communities by Joining in their Start by Believing Campaign. Motion carried unanimously. B. 2016-2017 Union Agreement Administrator Butkowski highlighted the process of negotiations and update the contract language. Contract continues past practice of wage increase and insurance benefit with a term of two years. Motion was made by Councilor Mac Lean and seconded by Councilor Grove to the 2016-2017 Agreement between the City of Lauderdale and the American Federation of State, County, and Municipal Employees Council 5. Motion carried unanimously on a roll call vote. C. Employee Handbook Revisions City Administrator Butkowski noted the revised document is considerably longer due to incorporating union contract language, respectful workplace language and drug and alcohol testing which was drafted by Terry Berg. The current respectful workplace policy will be repealed as part of the adoption. Motion was made by Gaasch and seconded by Mac Lean to adopt the Employee Handbook as presented and repeal the Respectful Workplace Policy adopted May 14, 2013. Motion carried unanimously on a roll call vote. Administrator Butkowski noted the next meeting may include the Annual Storm Water Report, Comprehensive Plan Request for Proposal and Storm Water Project Discussion with Capital Regions Watershed District. Work Session A. Public Comment Roger Herbst of 1843 Carl Street addressed the Council on the need of sidewalks on Eustis Street. Council response was that Eustis Street is a county street, so the City is working with Ramsey County on this need. LAUDERDALE CITY COUNCIL MEETING MINUTES Lauderdale City Hall 1891 Walnut Street Lauderdale, MN 55113 Page 3 of 3 April 26, 2016 B. Fence Extension Request for 1851 Carl Street City Administrator Butkowslci reported that Ashley Peterson of 1851 Carl Street made an extension to her fence without City approval or permit. Letter was sent from City staff. Roger Herbst of 1843 Carl Street questioned the valuation of neighboring property when an improvement of this type is made. Paul Roufs of 2383 Larpenteur Avenue provided copies of police reports a result of retaliation due to his complaint on fence extensions. Mayor Dains emphasized that the City Council did not approve fence extensions. Ashley Peterson of 1851 Carl Street explained that the improvement was installed so she could enjoy her yard without being harassed. There is a difference in elevation between properties in her neighborhood. In conclusion, Mayor Dains restated that the Council had denied this type of fence extension or barriers. Natural vegetation is an option for privacy. C. Community Television Planning Session Barbara Raye, Executive Director of the Center for Policy, Planning and Performance, conducted a planning session on behalf of CTV North Suburban Communications Commission. Response to the City should be by June. D. Community Update Administrator Butkowslci reported that Alison Ekland contacted the City to tour the City -owned service station for reuse as a bronze foundry, interest has been expressed in the Rapit Print building for catering business, planning grant of $10,000 is expected from the Metropolitan Council, the Benedictine Health Systems' conduit financing request should be closing in May and Lauderdale has qualified for Green Step Cities Step 2 and registration for the League of Minnesota Cities Annual Conference. The City newsletter has been sent to print. There being no further business on the council agenda, motion was made by Councilor Mac Lean and seconded by Councilor Grove, carried unanimously, to adjourn the meeting at 8:57 p.m. Respectfully submitted, o.1Te rrDepClerk CITY OF LAUDERDALE CLAIMS FOR APPROVAL May 10, 2016 City Council Meeting Payroll 05/06/16 Payroll: Direct Deposit # 502223-502228 05/06/16 Payroll: Payroll Liabilities, E -payments 1103E -1106E Vendor Claims 05/10/16 Claims: Check #'s 23315-23339 $9,596.78 $8,384.72 $86,459.821 SUBTOTAL $104,441.321 Total Claims for Approval $104,441.32 CITY OF LAUDERDALE 05/06/16 2:52 PM Page 1 Payments Current Period: MAY 2016 Batch Name 050616 PR Payment Computer Dollar Amt $8,384.72 Posted Refer 54221CMA RETIREMENT TRUST - 457 Ck# 001103E 5/6/2016 Cash Payment G 101-21705 ICMA RETIREMENT May 6 2016 Payroll $1,965.48 Invoice 102154897 5/6/2016 Transaction Date 5/6/2016 Due 0 NORTH STAR CHEC 10100 Total $1,965.48 Refer 5423 MN DEPARTMENT OF REVENUE Ck# 001104E 5/6/2016 Cash Payment G 101-21702 STATE WITHHOLDING May 6 2016 Payroll $628.50 Invoice 5/6/2016 Transaction Date 5/6/2016 Due 0 NORTH STAR CHEC 10100 Total $628.50 Refer 5424 NORTH STAR BANK, CHECKING S Ck# 001105E 5/6/2016 Cash Payment G 101-21701 FEDERAL TAXES May 6 2016 Payroll $1,438.80 Invoice 5/6/2016 Cash Payment G 101-21703 FICA WITHHOLDING. May 6 2016 Payroll $2,418.14 Invoice 5/6/2016 Transaction Date 5/6/2016 Due 0 NORTH STAR CHEC 10100 Total $3,856.94 $8,384.72 Pre -Written Checks $8,384.72 Checks to be Generated by the Computer $0.00 Total $8,384.72 CITY OF LAUDERDALE 05/06/16 2:46 PM Page 1 Payments Current Period: MAY 2016 Batch Name 051016CLAIMS Payment Computer Dollar Amt $86,459.82 Posted Refer 5419 ALLIANCE FOR INNOVATION Ck# 023315 5/10/2016 Cash Payment E 101-41200-308 TRAINING & EDUCATIO 2016 LMC Conference - J Bownik Invoice 92142383 4/26/2016 Transaction Date 5/1/2016 Due 0 NORTH STAR CHEC 10100 $400.00 Total $400.00 Refer 5413 BANYON DATA SYSTEM Ck# 023316 5/10/2016 Cash Payment E 101-41200-307 COMPUTER SERVICES 2016 Financial Software Annual Support -Fund Invoice 00154200 4/29/2016 Cash Payment E 101-41200-307 COMPUTER SERVICES 2016 Financial Software Annual Support - Payroll Invoice 00154200 4/29/2016 Transaction Date 5/1/2016 Due 0 NORTH STAR CHEC 10100 Total Refer 5415 CITY OF ROSEVILLE Cash Payment Invoice 0221387 Transaction Date E 101-41200-306 CONSULTING FEES 4/21/2016 Ck# 023317 5/10/2016 April IT Services 5/1/2016 Due 0 NORTH STAR CHEC 10100 $795.00 $795.00 $1,590.00 $492.33 Total $492.33 Refer 5416 CITY OF ROSEVILLE Ck# 023317 5/10/2016 Cash Payment E 101-41200-391 TELEPHONE/PAGERS April Telephone Services $90.84 Invoice 0221431 4/21/2016 Transaction Date 5/1/2016 Due 0 NORTH STAR CHEC 10100 Total $90.84 Refer 5443 CITY OF ST ANTHONY Ck# 023318 5/10/2016 Cash Payment E 101-42100-319 POLICE CONTRACT May Police Contract $54,418.83 Invoice 3393 4/28/2016 Transaction Date 5/5/2016 Due 0 NORTH STAR CHEC 10100 Total $54,418.83 1 Refer 5442 CROIX OIL Ck# 023319 5/10/2016 Cash Payment E 101-43000-212 MOTOR FUELS April Fuel $125.73 Invoice 445210 4/30/2016 Cash Payment E 601-49000-212 MOTOR FUELS April Fuel $26.94 Invoice 445210 4/30/2016 Cash Payment E 602-49100-212 MOTOR FUELS April Fuel $26.94 Invoice 445210 4/30/2016 Transaction Date 5/5/2016 Due 0 NORTH STAR CHEC 10100 Total $179.61 Refer 5412 EUREKA RECYCLING Ck# 023320 5/10/2016 Cash Payment E 203-50000-389 RECYCLING CONTRAC April Recycling $2,396.16 Invoice 16034 3/31/2016 Cash Payment E 203-50000-389 RECYCLING CONTRAC Revenue Share Processing Fee $99.44 Invoice 16034 3/31/2016 Transaction Date 5/1/2016 Due 0 NORTH STAR CHEC 10100 Total $2,495.60 Refer 5426 GOPHER STATE ONE CALL Ck# 023321 5/10/2016 Cash Payment E 101-43400-386 GOPHER STATE ONE C April Locates $36.25 Invoice 6040499 4/30/2016 Transaction Date 5/5/2016 Due 0 NORTH STAR CHEC 10100 Total $36.25 Refer 5429 HUGHES AND JOSEPH Ck# 023322 5/10/2016 CITY OF LAUDERDALE 05/06/16 2:46 PM Page 2 Payments Current Period: MAY 2016 Cash Payment E 101-41500-300 LEGAL FEES - PROSEC April $925.00 Invoice 0052 4/30/2016 Transaction Date 5/5/2016 Due 0 NORTH STAR CHEC 10100 Total $925.00 Refer 5441 LILLIE SUBURBAN NEWS Ck# 023323 5/10/2016 Cash Payment E 101-41100-352 PUBLIC INFORMATION 2015 Summary Financial Report $930.60 Invoice 4/29/2016 Cash Payment E 101-41100-352 PUBLIC INFORMATION Ordinance No 16-01 $343.20 Invoice 4/29/2016 Transaction Date 5/5/2016 Due 0 NORTH STAR CHEC 10100 Total $1,273.80 Refer 5435 MCFOA Ck# 023324 5/10/2016 Cash Payment E 101-41200-438 DUES & SUBSCRIPTIO 2016 Membership - Heather Butkowski $35.00 Invoice 2016-2 5/5/2016 Transaction Date 5/5/2016 Due 0 NORTH STAR CHEC 10100 Total $35.00 Refer 5427 MET COUNCIL ENVIRONMENTAL S Ck# 023325 5/10/2016 Cash Payment E 601-49000-387 WATER TREATMENT S June Wastewater Treatment $11,602.32 Invoice 0001055000 5/3/2016 Transaction Date 5/5/2016 Due 0 NORTH STAR CHEC 10100 Total $11,602.32 Refer 5418 NAPA AUTO PARTS Ck# 023326 5/10/2016 Cash Payment E 101-45200-201 GENERAL SUPPLIES Tire Bead Sealer $19.49 Invoice 666151 4/26/2016 Transaction Date 5/1/2016 Due 0 NORTH STAR CHEC 10100 Total $19.49 Refer 5448 NORTH STAR BANK, CHECKING S Ck# 023327 5/10/2016 Cash Payment E 101-41100-201 GENERAL SUPPLIES DVD's & Spindle $27.90 Invoice 4/28/2016 Cash Payment E 101-43000-202 PERMANENT SUPPLIE Rear Doors Entry Mats $100.94 Invoice 4/28/2016 Cash Payment E 101-43000-227 TOOLS & EQUIPMENT Double Tier Chair Truck $393.87 Invoice 4/28/2016 Cash Payment E 101-43000-227 TOOLS & EQUIPMENT City Hall Carpet Scrubber $139.08 Invoice 4/28/2016 Cash Payment E 101-41200-227 TOOLS & EQUIPMENT Tvalue Amortization Software $184.00 Invoice 4/28/2016 Cash Payment E 101-43000-202 PERMANENT SUPPLIE Truck Decals $69.44 Invoice 4/28/2016 Transaction Date 5/5/2016 Due 0 NORTH STAR CHEC 10100 Total $915.23 Refer 5414 ON SITE SANITATION Ck# 023328 5/10/2016 Cash Payment E 101-45200-427 PORTA POTTY RENTAL 4/23-05/20/2016 Portable Restroom $127.00 Invoice 0000241641 4/23/2016 Transaction Date 5/1/2016 Due 0 NORTH STAR CHEC 10100 Total $127.00 Refer 5428 PREMIUM WATERS, INC Ck# 023329 5/10/2016 Cash Payment E 101-41200-208 WATER DELIVERY April $23.19 Invoice 619861-04-16 4/30/2016 Transaction Date 5/5/2016 Due 0 NORTH STAR CHEC 10100 Total $23.19 Refer 5409 RAMSEY COUNTY, PROP REC & R Ck# 023330 5/10/2016 Cash Payment E 101-42100-442 MISCELLANEOUS April Fleet Support $6.24 Invoice EMCOM-005130 4/29/2016 CITY OF LAUDERDALE 05/06/16 2:46 PM Page 3 Payments Current Period: MAY 2016 Transaction Date 5/1/2016 Due 0 NORTH STAR CHEC 10100 Total $6.24 Refer 5420 RAMSEY COUNTY, PROP REC & R Ck# 023330 5/10/2016 Cash Payment E 101-43000-313 SNOW & ICE REMOVAL January and February Snowplowing Invoice PUBW-015486 4/21/2016 Transaction Date 5/1/2016 Due 0 NORTH STAR CHEC 10100 . Refer 5410 RAMSEY COUNTY, PROP REC & R Ck# 023330 5/10/2016 Cash Payment E 101-42100-318 911 DISPATCH April 911 Dispatch Invoice EMCOM-005144 4/29/2016 Transaction Date 5/1/2016 Due 0 NORTH STAR CHEC 10100 Refer 5411 RAMSEY COUNTY, PROP REC & R Ck# 023330 5/10/2016 Cash Payment E 101-42100-318 911 DISPATCH April 911 Dispatch CAD Invoice EMCOM-005159 4/29/2016 Transaction Date 5/1/2016 Due 0 NORTH STAR CHEC 10100 $4,813.20 Total $4,813.20 $1,177.13 Total $1,177.13 $254.03 Total $254.03 Refer 5446 RAMSEY COUNTY, PROP REC & R Ck# 023330 5/10/2016 Cash Payment G 101-21706 HEALTH INSURANCE June Insurance Premiums $383.20 Invoice RISK -001784 5/2/2016 $150.85 Invoice 16-31522 4/29/2016 Cash Payment E 101-41200-355 PRINTING SERVICES June Insurance Premiums $20.00 Invoice RISK -001784 5/2/2016 NORTH STAR CHEC 10100 Total Transaction Date 5/5/2016 Due 0 NORTH STAR CHEC 10100 Total $403.20 Refer 5421 RAMSEY COUNTY, REVENUE Ck# 023331 5/10/2016 1891 Walnut Street Cash Payment E 415-48100-442 MISCELLANEOUS 1821 Eustis Street Property Taxes $885.00 Invoice 2016-1 5/1/2016 Transaction Date 5/1/2016 Due 0 NORTH STAR CHEC 10100 Total $885.00 Refer 5447 RITEWAY BUSINESS FORMS Ck# 023332 5/10/2016 Cash Payment E 101-41200-355 PRINTING SERVICES Accounts Payable Checks $150.85 Invoice 16-31522 4/29/2016 Transaction Date 5/5/2016 Due 0 NORTH STAR CHEC 10100 Total $150.85 Refer 5430 ST PAUL REGIONAL WATER SERV Ck# 023333 5/10/2016 Cash Payment E 101-43000-382 WATER UTILITIES 1891 Walnut Street $59.11 Invoice 5/3/2016 Transaction Date 5/5/2016 Due 0 NORTH STAR CHEC 10100 Total $59.11 Refer 5431 ST PAUL REGIONAL WATER SERV Ck# 023333 5/10/2016. Cash Payment E 601-49000-382 WATER UTILITIES 1915 Walnut Street $23.44 Invoice 5/3/2016 Transaction Date 5/5/2016 Due 0 NORTH STAR CHEC 10100 Total $23.44 Refer 5432 ST PAUL REGIONAL WATER SERV Ck# 023333 5/10/2016 Cash Payment E 101-43000-382 WATER UTILITIES 2430 Larpenteur Avenue W $41.81 Invoice 5/3/2016 Transaction Date 5/5/2016 Due 0 NORTH STAR CHEC 10100 Total $41.81 Refer 5433 ST PAUL REGIONAL WATER SERV Ck# 023333 5/10/2016 Cash Payment E 101-45200-382 WATER UTILITIES 1885 Fulham Street $76.55 Invoice 5/3/2016 Transaction Date 5/5/2016 Due 0 NORTH STAR CHEC 10100 Total $76.55 Refer 5434 ST PAUL REGIONAL WATER SERV Ck# 023333 5/10/2016 CITY OF LAUDERDALE Payments Current Period: MAY 2016 Cash Payment E 101-43000-382 WATER UTILITIES 1821 Eustis Street Invoice 5/3/2016 Transaction Date 5/5/2016 Due 0 NORTH STAR CHEC 10100 Total Refer 5445 SUMMIT COMPANIES Ck# 023334 5/10/2016 Cash Payment E 101-43000-327 OTHER SERVICES Annual Fire Extinguishers Inspection Invoice 1120124 4/27/2016 Transaction Date 5/5/2016 Due 0 NORTH STAR CHEC 10100 Total 05/06/16 2:46 PM Page 4 S13.49 $13.49 $114.00 $114.00 Refer 5417 TRUCK UTILITIES INC Ck# 023335 5/10/2016 Cash Payment E 402-48000-560 VEHICLE 2016 Ford Truck Plow $3,120.00 Invoice 0297164 4/13/2016 Transaction Date 5/1/2016 Due 0 NORTH STAR CHEC 10100 Total $3,120.00 Refer 5444 WASTE MANAGEMENT Ck# 023336 5/10/2016 Cash Payment E 101-43000-384 REFUSE DISPOSAL May Public Works $227.95 Invoice 7374381-0500-6 5/1/2016 Transaction Date 5/5/2016 Due 0 NORTH STAR CHEC 10100 Total $227.95 Refer 5439XCEL ENERGY, 2430 LARPENTEU Ck# 023337 5/10/2016 Cash Payment E 101-43000-381 ELECTRIC UTILITIES 2430 Larpenteur Avenue $133.34 Invoice 499615750 4/29/2016 Transaction Date 5/5/2016 Due 0 NORTH STAR CHEC 10100 Total $133.34 Refer 5436 XCEL ENERGY, CITY HALL Ck# 023338 5/10/2016 Cash Payment E 101-43000-381 ELECTRIC UTILITIES 1821 Eustis Street $14.26 Invoice 499619152 4/29/2016 Cash Payment E 101-43000-383 GAS UTILITIES 1821 Eustis Street $12.55 Invoice 499619152 4/29/2016 Transaction Date 5/5/2016 Due 0 NORTH STAR CHEC 10100 Total $26.81 Refer 5440 XCEL ENERGY, CITY HALL Ck# 023338 5/10/2016 Cash Payment E 101-43000-381 ELECTRIC UTILITIES 1891 Walnut Street $142.40 Invoice 499525855 4/29/2016 Cash Payment E 101-43000-383 GAS UTILITIES 1891 Walnut Street $85.46 Invoice 499525855 4/29/2016 Transaction Date 5/5/2016 Due 0 NORTH STAR CHEC 10100 Total $227.86 Refer 5437 XCEL ENERGY, STREET LIGHTING Ck# 023339 5/10/2016 Cash Payment E 101-43000-380 STREET LIGHTING Larpenteur Bridge Lights $37.91 Invoice 499582433 4/29/2016 Transaction Date 5/5/2016 Due 0 NORTH STAR CHEC 10100 Total $37.91 Refer 5438 XCEL ENERGY, STREET LIGHTING Ck# 023339 5/10/2016 Cash Payment E 101-43000-380 STREET LIGHTING Larpenteur Avenue $43.41 Invoice 499616668 4/29/2016 Transaction Date 5/5/2016 Due 0 NORTH STAR CHEC 10100 Total $43.41 CITY OF LAUDERDALE 05/06/16 2:46 PM Page 5 Payments $86,459.82 Pre -Written Checks $86,459.82 Checks to be Generated by the Computer $0.00 Total $86,459.82 Current Period: MAY 2016 Fund Summary 10100 NORTH STAR CHECKING 602 STORM SEWER ENTERPRISE FUND $26.94 601 SEWER UTILITIES $11,652.70 415 HOUSING REDEVELOPMENT $885.00 402 CAPITAL IMPROVEMENTS $3,120.00 203 RECYCLING $2,495.60 101 GENERAL $68,279.58 $86,459.82 Pre -Written Checks $86,459.82 Checks to be Generated by the Computer $0.00 Total $86,459.82 LAUDERDALE COUNCIL ACTION FORM Action Requested Consent X_ Public Hearing Discussion Action Resolution Work Session Meeting Date May 10, 2016 ITEM NUMBER Non -Union Compensation STAFF INITIAL APPROVED BY ADMINISTRATOR DESCRIPTION OF ISSUE AND PAST COUNCIL ACTION: In the past, the Council extended the pay and benefits agreed to in the union contract to non- union staff. Past practice has also been to do it under the same terms, meaning it would be effective January 1. The Council may elect to do that for 2016 as well. OPTIONS: Extend or do not extend the benefits of the union agreement to non-union employees. STAFF RECOMMENDATION: By approving the Consent Agenda, the benefits of the union agreement are extended to non- union employees effective January 1, 2016. COUNCIL ACTION: LAUDERDALE COUNCIL ACTION FORM Action Requested Consent Public Hearing Discussion X Action Resolution X Work Session Meeting Date May 10, 2016 ITEM NUMBER National Peace Officers Week STAFF INITIAL APPROVED BY ADMINISTRATOR DESCRIPTION OF ISSUE AND PAST COUNCIL ACTION: Attached is a resolution for Council consideration for this year's police week. Staff will pre- sent a copy of the resolution to Chief Ohl after adoption. STAFF RECOMMENDATION: Motion to adopt Resolution 051016A— A Resolution Recognizing National Police Week 2016 and to Honor the Sacrifice of Law Enforcement Officers Killed in the Line of Duty while Protecting our Communities and Safeguarding our Democracy. COUNCIL ACTION: RESOLUTION NO. 051016A CITY OF LAUDERDALE COUNTY OF RAMSEY STATE OF MINNESOTA A RESOLUTION RECOGNIZING NATIONAL POLICE WEEK 2016 AND TO HONOR THE SERVICE AND SACRIFICE OF LAW ENFORCEMENT OFFICERS KILLED IN THE LINE OF DUTY WHILE PROTECTING OUR COMMUNITIES AND SAFEGUARDING OUR DEMOCRACY. WHEREAS, there are approximately 900,000 law enforcement officers serving in communities across the United States, including the dedicated members of the SaintAnthony Police Department; WHEREAS, nearly 15,725 assaults against law enforcement officers in 2014, resulting in approximately 13,824 injuries; WHEREAS, since the first recorded death in 1791, almost 20,000 law enforcement officers in the United States have made the ultimate sacrifice and been killed in the line of duty; WHEREAS, the names of these dedicated public servants are engraved on the walls of the National Law Enforcement Officers Memorial in Washington, D.C.; WHEREAS, 252 names of fallen heroes are being added to the National Law Enforcement Officers Memorial this spring, including 123 officers killed in 2015 and 129 officers killed in previous years; WHEREAS, the service and sacrifice of all officers killed in the line of duty will be honored during the National Law Enforcement Officers Memorial Fund's 281h Annual Candlelight Vigil, on the evening of May 13, 2016; WHEREAS, the service and sacrifice of all officers killed in the line of duty will be honored during the Minnesota Law Enforcement Memorial Association's Annual Candlelight Vigil, on the evening of May 15, 2016; WHEREAS, the Candlelight Vigil is part of National Police Week, which takes place this year on May 15-21; WHEREAS, May 15 is designated as Peace Officers Memorial Day, in honor of all fallen officers and their families; WHEREAS, the service and sacrifice of Ramsey County Suburban Law Enforcement officers killed in the line of duty will be honored during the Suburban Ramsey County Law Enforcement Memorial Ceremony on May 12, 2016; NOW, THEREFORE, BE IT RESOLVED that the City Council of the City of Lauderdale formally designates May 15-21, 2016, as Police Week in the City of Lauderdale, and publicly salutes the service of law enforcement officers in our community and in communities across the nation. ADOPTED by the City Council of Lauderdale this 10th day of May, 2016. Jeffrey Dains, Mayor Attest: Heather Butkowski, City Administrator LAUDERDALE COUNCIL ACTION FORM Action Requested Consent Public Hearing Discussion Action Resolution Work Session X Meeting Date May 10, 2016 ITEM NUMBER Cow irls Killer Catering STAFF INITIAL —I- � & APPROVED BY ADMINISTRATOR DESCRIPTION OF ISSUE AND PAST COUNCIL ACTION: Staff recently met with Chowgirls Killer Catering owners to discuss their plans to use 2520 Larpenteur Avenue (the former Rapit Print building) for their catering business. They also would like to introduce their business to the City Council. I am expecting owners Heidi An- dermack and Amy Brown to attend in addition to their CFO Todd Churchill. Duane Arens, who will be purchasing the property, also plans to attend. Staff have been looking into whether catering is an allowed use in the I-1 district as well as what other ordinances may need to change to accommodate their business. Per state law, Chowgirls Killer Catering needs the City to issue both an on -sale intoxicating liquor license as well as a restaurant license in order to get their "Caterer's Permit with Alcohol" license. As City Code currently doesn't provide for the issuing of on -sale intoxicating liquor licenses and the "Foodstuffs" ordinance doesn't address catering, both would need to be updated. Both of these could be done relatively quickly if the Council supported the changes. The ordinance can be drafted in such as way as to protect the City's right to keep the municipal liquor store option open or not allow off -sale liquor by another entity, which staff explained to Heidi and Amy would be important to the City Council. STAFF RECOMMENDATION: LAUDERDALE COUNCIL ACTION FORM Action Requested Consent Public Hearing Discussion Action Resolution Work Session X Meeting Date May 10, 2016 ITEM NUMBER Capitol Regions WD STAFF INITIAL A& APPROVED BY ADMINISTRATOR DESCRIPTION OF ISSUE AND PAST COUNCIL ACTION: Anna Eleria of Capitol Regions Watershed District (CRWD) will be at the meeting. She is coming to discuss the work the watershed has done to research drainage and water quality issues through the Nature Area to Eustis Street. This has been a part of the discussions to plan for a sidewalk from Eustis Street to the City's border with St. Paul. CRWD was asked to join the sidewalk conversations to bring expertise about how to handle the rain water from Eustis Street and the City's storm water pond as they converge near Greenway Village Apartments. CRWD researched options with an engineer from Barr Engi- neering. CRWD paid for the study; portions of it follow. The outcome of their efforts was presented to the City, County, and Greenway Village Own- ers last year. The design was focused on plantings, walls, and rain gardens along Eustis Street and the concrete drainage swales to improve water quality and meter the flow of wa- ter. Greenway Village Owners felt the efforts should be focused on controlling water further up in the subwatershed so less of it reached their property. Their plan is to convey the storm water coming through their site via underground pipes. CRWD agreed to tackle the challenge of determining options for improvements upstream. CRWD again hired Barr Engineering to do the analysis. The second report is also included in the packet. Barr determined that an option to minimize flooding in the parking lots of Greenway Village Apartments and improve water quality would be to convert the City's dry storm water pond to a wet pond and install an iron enhanced sand filter around the pond, which would remove phosphorus from the water before it continues toward the Mississippi River. The cost of the system is approximately $500,000 including engineering design and con- struction. Knowing the high cost, discussions have focused on a way to make it financially feasible. CRWD Board budgeted $100,000 dollars to work with Lauderdale on a project this year. About $10,000 of that has been spent on the study leaving $90,000 for final de- sign and construction. Anna also submitted an application to the Pollution Control Agen- cy's Clean Water Revolving Fund to get the project on the PCA's funding radar. We also met with the Mississippi Watershed Management Organization as it was believed that some of the water leaving the City ultimately flowed to Minneapolis. Unfortunately, that was de- termined to not be the case so the MWMO is unable to assist financially. Other jurisdictions contribute to the storm water in this area; we may be able to get assistance from them. DESCRIPTION OF ISSUE AND PAST COUNCIL ACTION: Beyond being a good thing to do for the environment, you may be questioning why the City would consider spending so much money on this type of infrastructure project right now. Currently, there aren't any Total Maximum Daily Load (TMDL) requirements the City is obligated to meet but they are coming as the Mississippi River has compromised water qual- ity and each City that sends water to the Mississippi River will be under a mandate to im- prove water quality within their community before sending it downstream. Lauderdale would be ahead of the game by doing this project. Anna will be at the meeting to explain this in more technical terms with the goal of getting the Council's perspective and level of interest in pursuing this project so they know whether to continue designing the project this year with the goal of construction next year. STAFF RECOMMENDATION: Eustis Street Living Streets Stormwater Improvements Lauderdale, MN Preliminary Concepts and Feasibility Study Capitol Region Watershed District Saint Paul, MN DRAFT - December 2014 2.0 Alternatives 1 A and 1 B: Maximum Treatment Alternatives lA and 1B utilize the full study area, as identified in the RFP and shown on Figure 1, for stormwater treatment and treat the maximum amount of impervious surfaces from the public and private realm. Alternatives lA and 1B are shown in Figures 4 and 5. 2.1 Northern Treatment Area (Between Idaho and Northern Driveway along Eustis Street) In both Alternatives 1A and 1B, the stormwater treatment is provided at the surface, treating stormwater runoff from Eustis Street, downstream of the catch basin at Eustis Street and Idaho Avenue. Both alternatives include linear rain gardens on either side of the sidewalk. The western gardens along Eustis Street take runoff from Eustis Street while the eastern gardens collect runoff from Idaho Avenue (redirecting flow from an existing catch basin on Idaho Avenue) and the parking lot. The rain gardens are designed to be offline such that when the gardens fill up, flows will generally bypass the rain gardens and flow further to the south, with the exception of the garden receiving runoff from Idaho Street; overflows from that garden enter the rain garden to the south, with high flows flowing through the garden into a high capacity inlet that direct flows into the high flow bypass in the Middle Treatment Area. 2.2 Middle Treatment Area (Between Northern and Middle Driveways along Eustis Street) In both Alternatives 1A and 1B, rain gardens are provided at the surface to treat, separately, runoff from Eustis Street and the parking lot. The gardens are designed to be offline such that when the gardens fill up flows will generally bypass the rain gardens and flow further to the south. Alternatives 1A and 1B differ in the approach to conveying upstream flows through the study area. Currently, high flows are conveyed through the area in a concrete channel. 2.2.1 Alternative 1 A: Daylighted High Flow Channel In Alternative 1A, the high flows, including the untreated 15 -acre subwatershed north of Idaho Street, are daylighted in a high flow channel, with vertical sidewalls, that flows between the rain gardens that separately treat the roadway and parking lot runoff. The channel are reinforced with large stones. This alternative daylights the maximum amount of runoff and flows. This alternative allows for two rain gardens along Eustis Street treating runoff from Eustis Street and two rain gardens along the parking lot treating runoff from the parking lots. High flows that bypass the Eustis Street garden enter the high flow channel near the existing high capacity inlets through a new catch basin south of the rain garden inlet. High flows that bypass the parking lot gardens enter the high flow channel near the existing high capacity inlets through the existing parking lot curb cut. 2.2.2 Alternative 1 B: Buried High Flow Pipe In Alternative 1B, the high flows from upstream of the study area (north of Idaho Street) are carried through a pipe extended from the existing stormsewer north of the driveway all the way to the existing outlets from the concrete channel. High flows that bypass the Eustis Street garden enter the high flow channel near the existing high capacity inlets through a new catch basin south of the rain garden inlet. High flows that bypass the parking lot gardens enter the high flow channel near the existing high capacity inlets through the existing parking lot curb cut. 2.3 Southern Treatment Area (South of Middle Driveway along Eustis Street to Southern Driveway/City Limits) There is a low-lying area that is currently providing limited treatment for the adjacent property along Eustis Street between the middle and southern driveways. Alternatives 1A and 1B enhance that treatment area with improved vegetation and an enhanced -iron filtration basin. In addition, runoff from Eustis Street is treated in boulevard rain gardens between the street and the proposed sidewalk. 2.4 East-West Treatment Area (along existing east -west concrete channel) Alternatives 1A and 1B provide treatment for runoff from the adjacent apartment complex parking lot and buildings. Because the flows in the existing concrete channel have already received stormwater treatment in upstream ponds, those flows are kept separate, and the channel is softened and moved south to accommodate treatment along the edge of the parking lot. While no treatment of flows from the concrete channel occurs in these alternatives, storage areas along the channel are created using check dams so that pooling and watering of plantings and trees occurs, reducing runoff volume. The northern edge of the channel could either be delineated by a low-rise retaining wall or an earthen berm. Runoff from the apartment complex parking lot is treated in rain gardens located north of the proposed softened channel. 3.0 Alternatives 2A and 2B: Treatment in Drainage Easement Alternatives 2A and 213 utilize only the drainage easements within the study area, as identified in drawings received from CRWD in August and October 2014, for stormwater treatment to treat impervious surfaces from Eustis Street alone. While this option requires some amount of grading and landscaping outside of the drainage easement on private property, no permanent stormwater management is performed on private property outside of the drainage easement. The primary difference between Alternatives 2A and 213 is in the location of the treatment along Eustis Street. In Alternative 2A all treatment occurs at the surface in enhanced -iron filtration basins, while in Alternative 213 all treatment occurs subsurface in tree trenches with a final enhanced -iron polishing step. 3.1 Northern Treatment Area (Between Idaho and Northern Driveway along Eustis Street) In Alternatives 2A and 213, only Eustis Street is treated by practices adjacent to the roadway; no treatment of Idaho Avenue or private property is provided. In either alternative, the practices (gardens or tree trenches) are designed to be offline such that when the practices fill up flows will bypass the practices and flow further to the south. 3.2 Middle Treatment Area (Between Northern and Middle Driveways along Eustis Street) In Alternatives 2A and 213, only Eustis Street is treated by practices adjacent to the roadway; no treatment of private property is provided. In either alternative, the practices (gardens or tree trenches) are designed to be offline such that when the practices fill up flows will bypass the practices and flow further to the south. High flows that bypass the practices enter the high flow channel near the existing high capacity inlets through a new catch basin south of the rain garden inlet. In both alternatives, the existing high flow concrete channel is replaced by a pipe to convey flows from the north to the existing high capacity inlets. 3.3 Southern Treatment Area (South of Middle Driveway along Eustis Street to Southern Driveway/City Limits) In Alternatives 2A and 2B, only Eustis Street is treated by practices adjacent to the roadway; no treatment of private property is provided. In either alternative, the practices (gardens or tree trenches) are designed to be offline such that when the practices fill up flows will bypass the practices and flow further to the south. U. 3.4 East-West Treatment Area (along existing east -west concrete channel In Alternatives 2A and 2B, the existing concrete channel is softened and meandered to create some interest within the proposed easement (proposed in August 2014 plat, but not in October 2014 plat). While no engineered treatment of flows from the concrete channel occurs (these flows have already been treated by upstream ponds/wetlands), storage areas along the channel are created using check dams so that pooling and watering of plantings and trees could occur, reducing runoff volume. No additional treatment of private property occurs. 4.0 Artful Stormwater Design Elements Landforms and materials will be designed and selected to echo natural riparian landscapes found in this area prior to settlement with meandering, river rock -lined channels, native upland and wetland vegetation, and erratic features such as fallen logs and stone outcrops that function as retaining walls and weirs. These features would likely be made of stone, and can also serve as seating or climbing structures for people passing through the site, inviting visitors to sit and rest amongst the gardens and tree groves or to explore along the length of the river cobble channel and follow the path of stormwater through the site. These hardscapes elements, including the proposed sidewalk paving and railing, also provide opportunities to incorporate public art through the use of various surface treatments, such as embedded graphics and text. These treatments could communicate the hydraulic function of the BMPs, or reference site history, or could be an opportunity to engage local residents, and invite them to 'make their mark' on the project. Additionally, incorporating elements that evoke the historic streetcar line that passed through the site, such as rails or ties, can allow the passerby to learn about the history of the Eustis Street corridor. r 10 Figures Figure 1 Study Area and Known Utilities Figure 2 Watershed Divides - Alternatives l A and 1 B Figure 3 Watershed Divides - Alternatives 2A and 2B Figure 4 Alternative 1 A Figure 5 Alternative 1 B Figure 6 Alternative 2A Figure 7 Alternative 2B 926 \ 92 Nlaho Ave\ 910 °(\\/ o � 908 \ 97 _ \\I97q 16 992 �I /Oi 0� ll { r Y 904 f -- `ji ® 49 sot 900 x i A a 898 O d il0 � i 0 N N l � 8g6� i o ss4 a 4 N ZD lN N �ae2 N CD U Q UI O O LL Imagery: Micr oft; 201 Project Area Utilities (Site Visit GPS) Utility Locations N Municipal Cable O Gas Valve Boundary Xcel O Hydrant Feet rl Parcel Boundary (2009) Utility Lines ® Light Pole 80 0 80 2 -Foot Contour (MN DNR, 2011) -- Overhead Electric 0 Power Pole AL Boring Locations Sanitary • Sign Figure 1 Storm O Storm CB Water O Storm MH STUDYAREAAND KNOWN UTILITIES O Eustis Street Stormwater Improvements Telephone MH Capitol Region Watershed District 944 946 942 m 63% I i, 926 928 9 0 •936, 8 u v 924 934 20 922 932_ ' ILiu2 J�,2 IQ, daho'Avz a I - - -- -- - - - - - - — --- - O �f d j \ "S \ rn i 1 � `OI � Q N � .9 v t J � o w� L III 3 li II N C7 _ � 1 d I t� 1 Li � � I FO o _ U F - ¢` I z I o � o ' �� -- I a : Mi o )ft) O Feet 100 0 100 FQ Project Area Municipal Boundary Figure 2 2 -Foot Contour (MN DNR, 2011) WATERSHED DIVIDES -ALTERNATIVES 1AAND 113 O Subwatersheds Eustis Street Stormwater Improvements Capitol Region Watershed District VID 926--__ 26 928 924 n w m\� 92,2 2�� M 936 932 Q W CZLlj15 Z I�I i I a : M O O Feet 100 0 100 Project Area Municipal Boundary Figure 3 2 -Foot Contour (MN DNR, 2011) WATERSHED DIVIDES -ALTERNATIVES 2AAND 213 Q Subwatersheds Eustis Street Stormwater Improvements Capitol Region Watershed District W N e U W -------------------------- ----------- — VMiddle 'vewa m � w m a - nm 3v Efun GQ=�t W Z i° m o z o 3 U u LC&J C y W G LU O LLI y O C N „I u UE w a 3 A = E y c South Driveway z" 9 w a` a °a L N Idaho Drive w J 1 \ 1 ..------------------ a-- ---- -7 a �a F m South Driveway w ii Iz 0 ti V W m I Idaho Drive z South Driveway h+ South Idaho Drive j a u Og ■, a n 1 n ■r 3 j E= v`L W E o u a 3 •3 w •� E t - t« v o 3 to _ 4 v h c O p ❑E `�. 6 ❑ � Vi Ov Qq N H v Uj W V W G c s 5 a W 3 a N o O c w � w j LNL v`L W _ •3 w •� v o 3 to 4 v h O p ❑E `�. 6 ❑ � Vi Ov Qq N H v Uj W V W g 5 a W 3 a N o O c Z Q c v o 0 W Qa�.�❑�a v •c � Ed C G Q0 0 mH W aa=� N Regional Watershed Technical Report: Eustis Street Regional Modeling_ BY CAPITOL REGION WATERSHED DISTRICT Barr Engineering Co. Lauderdale, Minnesota March 2016 Q��O � RF IU S�/ED 0�5 Technical Report: Eustis Street Regional Modeling March 2016 Contents 1.0 Background................................................................................................................................................................................1 1.1 Purpose...........................................................................................................................................................................1 1.2 Background and Scope.............................................................................................................................................1 1.3 Study Area......................................................................................................................................................................3 2.0 Hydraulic and Hydrologic Modeling................................................................................................................................5 2.1 Field survey of stormsewer network....................................................................................................................5 2.2 Delineation of Subwatersheds and Field Review............................................................................................5 2.3 Hydrologic Modeling.................................................................................................................................................5 2.3.1 Land Use and Imperviousness...............................................................................................................5 2.3.2 Soils and Infiltration...................................................................................................................................6 2.3.3 Watershed Width and Slope..................................................................................................................6 2.3.4 Rainfall.............................................................................................................................................................6 2.4 Hydraulic Modeling....................................................................................................................................................9 2.4.1 Stormsewer and Stormsewer Inlets.....................................................................................................9 2.4.2 Open -channels and Overflow Conduits............................................................................................9 3.0 Water Quality Modeling......................................................................................................................................................10 3.1 Hydrologic Modeling...............................................................................................................................................10 3.2 Hydraulic and Particulate Modeling..................................................................................................................10 4.0 Modeling Results...................................................................................................................................................................11 4.1 Hydraulic Results.......................................................................................................................................................11 4.2 Water Quality Results..............................................................................................................................................15 5.0 Potential Watershed Improvements..............................................................................................................................21 5.1 Flood Mitigation........................................................................................................................................................21 5.1.1 Earthen Berm in Ravine..........................................................................................................................23 5.1.2 Expansion of Gasperre Pond(CB99013)..........................................................................................24 5.1.3 Expansion of Seminary Pond and Sheet Pile Wall(CB99027).................................................25 5.1.4 Expansion of Seminary Pond and Earthen Berm(CB99027)....................................................26 i \\barr.com\projects\Mpls\23 MN\62\23621162 Eustis St Strmwtr Improvement\WorkFiles\Watershed Study\Report\Eustis Regional Modeling-Re port_031516.docx 5.1.5 Expansion of Storage at Confluence(CB99029)...........................................................................27 5.1.6 Combined Flood Mitigation Alternative..........................................................................................27 5.2 Water Quality..............................................................................................................................................................32 5.2.1 Redevelopment of Gasperre Pond (CB99013)..............................................................................32 5.2.2 Conversion of Seminary Pond to Wet Pond(CB99027)............................................................32 5.2.3 Conversion of Seminary Pond to Wet Pond with IESF(CB99027).........................................33 5.2.4 Residential Rain Gardens.......................................................................................................................34 5.2.5 BMP Cost and Cost-Benefit..................................................................................................................36 6.0 Recommendation..................................................................................................................................................................38 7.0 References................................................................................................................................................................................41 Appendix................................................................................................................................................................................................42 List of Tables Table 1 Directly connected impervious fraction by surface type and land use..........................................7 Table 2 Horton infiltration parameters by hydrologic soil group....................................................................7 Table 3 Selected Atlas 14 design event inundation elevations.......................................................................11 Table 4 Comparison of peak outflow rates.............................................................................................................12 Table 5 Average annual TSS and TP load reduction...........................................................................................15 Table 6 Storage and peak flow comparison at the proposed earthen berm............................................24 Table 7 Storage and peak flow comparison at the proposed expansion of Gasperre Pond..............25 Table 8 Storage and peak flow comparison at the proposed expansion of Seminary Pond and sheetpile wall.....................................................................................................................................................26 Table 9 Storage and peak flow comparison at the proposed expansion of Seminary Pond and earthenberm......................................................................................................................................................27 Table 10 Flood mitigation alternative hydraulic summary..................................................................................28 Table 11 Flood mitigation alternative capital costs and annualized costs...................................................31 Table 12 Annual TSS and TP reduction from proposed redeveloped of Gasperre Pond.......................32 Table 13 Annual TSS and TP reduction provided by conversion of Seminary Pond to wet pond ...... 33 Table 14 Annual TSS and TP reduction provided by conversion of Seminary Pond to wet pond withIESF and earthen berm..........................................................................................................................34 Table 15 Residential rain garden sizing......................................................................................................................34 Table 16 Annual water load, TSS, and TP reduction provided by residential rain gardens...................34 Table 17 Water quality BMP capital cost, annualized cost, and cost-benefit..............................................37 Table 18 Proposed alternative capital cost, annualized cost, and cost-benefit..........................................40 List of Figures Figure 1 Concrete swales located near 1568 Eustis Street (junction of swales, north-west swale, east -west swale)...................................................................................................................................................2 Figure 2 Eustis Street study area.....................................................................................................................................4 Figure3 Eustis Street hydrology.....................................................................................................................................8 Figure 4 Design event inundation area......................................................................................................................13 Figure 5 10 -year design event pipe capacity...........................................................................................................14 Figure6 Areal TSS loading..............................................................................................................................................16 Figure7 Areal TP loading................................................................................................................................................17 Figure8 Water quality treatment.................................................................................................................................18 Figure9 TSS load reduction.................................................................................................................:..........................19 Figure10 TP Load reduction.............................................................................................................................................20 Figure 11 Rating curve for combined outflow from the 24-inch and 36-inch outlet pipes at the confluence of the concrete swales.............................................................................................................22 Figure 12 Existing condition outflow hydrograph from the confluence of the concrete swales........... 22 Figure 13 Flood Mitigation Alternative.........................................................................................................................29 Figure 14 Existing condition compared to combined flood mitigation alternative for 10-year designevent........................................................................................................................................................30 Figure 15 Existing condition compared to combined flood mitigation alternative for 100-year designevent........................................................................................................................................................30 Figure16 Residential Rain Gardens...............................................................................................................................35 Figure 17 Profile: Seminary Pond expansion and conversion to wet pond...................................................38 iv 1.0 Background 1.1 Purpose The purpose of this technical report is to summarize regional modeling efforts to determine the 10- and 100 -year flow rates and pollutant loading for the watershed tributary to the concrete swales near 1568 Eustis Street in Lauderdale, Minnesota. 10- and 100 -year flows were evaluated by creating a hydraulic and hydrologic model of the 148 -acre drainage area to the concrete swales, and localized flooding was evaluated. Additionally, a water quality model of the drainage area was created to assess the total suspended solids (TSS) and total phosphorus (TP) removal efficiency of several dry and wet ponds tributary to the concrete swales. The developed water quantity and water quality models were used to evaluate the impact of several flood mitigation alternatives and water quality projects throughout the study area. Water quality improvement projects evaluated were targeted at portions of the study area which were identified as having little or no water quality treatment. Flood mitigation alternatives were evaluated with the goal of protecting the apartment complex immediately northeast of the concrete swales during the 10- and 100 -year design storm events, and minimizing inundation of the apartment complex parking lot during the 10 -year event. Flood inundation and water quality modeling methodology and modeling results are outlined in Sections 1.0 through 4.0 of this report. Flood mitigation alternatives and water quality improvement projects evaluated are discussed in Section 5.0. 1.2 Background and Scope At the request of City of Lauderdale, Ramsey County, and the property owner of 1568 Eustis Street, Capitol Region Watershed District (CRWD) has determined the capacity and potential flooding concerns of a concrete swale drainage system located in the city of Lauderdale near 1568 Eustis Street (Figure 1). The swale system (Figure 2) consists of two concrete swales which drain to the 36 -inch and 24 -inch outlet pipes shown in Figure 1. The north -south swale and east -west swale are roughly 125 and 220 feet long, respectively. Both swales are, on average, four feet wide, and have a maximum depth of six to nine inches. The total drainage area to the east -west swale is 129 acres. The drainage area to the north -south swale is 15 acres, and direct drainage area to the confluence of both swales (subwatershed CB99029 in Figure 2) is 4 acres, leading to a total drainage area of 148 acres. City staff and the landowner (Aspen Waste Management) state that the parking lot adjacent to the concrete swales (shown in Figure 2) frequently floods, requiring tenants of a nearby apartment complex to avoid the low area in the southwest portion of the parking lot during heavy rainfall events (see signage in Figure 1). To evaluate the hydraulic performance of the concrete swale drainage system and assess the extent of localized flooding, a hydraulic and hydrologic model of the total 148 -acre drainage area (Figure 2) was created using XP-SWMM version 2014. Figure 1 Concrete swales located near 1568 Eustis Street (junction of swales, north-west swale, east -west swale) The stormsewer network in the 148 -acre drainage area to the concrete swale system was digitized from stormsewer alignments and as-builts received from Ramsey County and the Cities of Falcon Heights and Lauderdale. The as-builts and alignments had complete data coverage of Larpenteur Avenue West through the project area, as well as small portions of Eustis Street, Carl Street, Pleasant Street, and Coffman Street. All other stormsewer in the watershed (an estimated 60-70% of stormsewer in the drainage area), was generated from field inspection surveys conducted by CRWD and Barr Engineering Co (Barr) staff. Final stormsewer data, created by combining available data from as-builts and alignments with data collected during field inspection surveys, was used to evaluate the hydraulic performance and flood inundation throughout the 148 -acre drainage area. Additionally, water quality performance of several ponds upstream of the east -west concrete swale was evaluated using the P8 (Program for Predicting Pollution Particle Passage through Pits, Puddles, and Ponds) Urban Catchment Model. Data from the final XP-SWMM model; as well as pond outlet information and bathymetry data from field investigations; and as-builts were used to create device and watershed modeling parameters used in the P8 model. Below is a summary of tasks performed to complete the water quality model and hydraulic and hydrologic analysis of the concrete swale drainage system: 1. Create modeled stormsewer network by combining data from as-builts and alignments with data collected during field survey inspections. 2. Delineate and field -verify subwatersheds to the location of localized flooding and nearby storm sewer inlets. 3. Develop an XP-SWMM model of the study area to assess the hydraulic performance of the concrete Swale system and evaluate localized flooding. 4. Develop a P8 model to evaluate TSS and TP loading within the drainage area, as well as assess the TSS and TP removal efficiency of four (4) dry and wet ponds. 1.3 Study Area The study area includes all potential sources of direct drainage to the concrete swales near 1568 Eustis Street. This area is generally bounded to the North, East, South, and West by Ione Street, North Cleveland Avenue, West Hoyt Avenue, and Eustis Street, respectively. The extent of the 148 -acre drainage area, subwatershed divides, and the location of localized flooding is shown in Figure 2. St Oq Fl O L W W a) 0 0 CD L ^ VJ L Cl) Z O � 1 c m 0) U) 0� c U o LO N LL U) O U) =3 W :5 u) N W O 2.0 Hydraulic and Hydrologic Modeling 2.1 Field survey of stormsewer network As discussed in Section 1.2, the as-builts and alignments from Ramsey County and the Cities of Lauderdale and Falcon Heights covered roughly 30 percent of the total stormsewer located within the 148 -acre drainage area. The remaining stormsewer was digitized from field surveys conducted by CRWD and Barr staff (two surveys completed June 25, 2015 and July 1, 2015). During field surveys, staff measured relative depths to inverts and pipe sizes using a laser -sight depth meter, which allowed the survey to be performed without entry into the structures. Relative depths were later compared to LiDAR data at the horizontal location where each data -point was collected to determine the elevation of the pipe inverts. Measured inverts and pipe sizes aligned well with available as -built data. The final modeled stormsewer network (Figure 2) is the combination of as -built and collected field survey data. 2.2 Delineation of Subwatersheds and Field Review Barr delineated subwatersheds throughout the 148 -acre drainage area to catch basin clusters and storage areas (low areas, ponds, etc.) using the data sources outlined below: • High resolution (1 -meter grid resolution) LiDAR data for Ramsey County collected in 2011. • As-builts of stormsewer received from Ramsey County and the Cities of Falcon Heights and Lauderdale. • Stormsewer data collected during two field surveys conducted by CRWD and Barr staff. Divides were field -verified during stormsewer field surveys. Figure 2 shows the final subwatershed divides used in XP-SWMM and P8 modeling efforts. A total of 49 subwatersheds were defined within the study area, ranging in area from 0.1 to 13 acres, with an average area of three (3) acres. 2.3 Hydrologic Modeling The XP-SWMM model was developed using similar hydrologic parameters as those used in the 2012 XP-SWMM Trout Brook Interceptor (TBI) model for the CRWD. Calibration parameters used in the TBI 2012 study pertaining to various Horton infiltration parameters and impervious depression storage were not applied to this project area, as drainage to the concrete Swale is not ultimately tributary to the TBI. The following sub -sections outline hydrologic modeling methodology and assumptions developed for the XP-SWMM model. Modeled hydrologic parameters for all subwatersheds are shown in Table A of the Appendix. 2.3.1 Land Use and Imperviousness The same methodology used in the 2012 XP-SWMM TBI model to define land use and related imperviousness was used in this study to calculate total impervious area, directly connected impervious area, and impervious depression storage for each of the 49 subwatersheds in the study area. A vector- based impervious dataset received from CRWD (Figure 3), delineating impervious area surface type, was used to calculate the total impervious area for each subwatershed. To calculate the directly connected impervious area, the impervious dataset was intersected with the 2010 Metropolitan Council land use data (also provided by CRWD). Directly connected impervious fractions for each impervious surface type and land use combination (Table 1) were applied and used to calculate the fraction of total impervious which is directly -connected. Impervious depression storage of 0.06 -inches and impervious Manning's roughness of 0.015 was assumed, consistent with the hydrologic parameters used in the 2012 XP-SWMM TBI model. 2.3.2 Soils and Infiltration Soil and infiltration assumptions were designed to match assumptions made for the 2012 XP-SWMM TBI model. The infiltration modeling parameters were based on Horton infiltration, and infiltration modeling parameters for pervious areas were defined by hydrologic soil group (Table 2). Final infiltration parameters were determined by calculating the area of each hydrologic soil group in each subwatershed from a vector -based file received from CRWD (Figure 3). 2.3.3 Watershed Width and Slope Watershed width is a parameter used in XP-SWMM to define subwatershed time of concentration, as described in the SWMM user's manual, Storm Water Management Model; Version 4 User's Manual, U.S. EPA 1988. Matching the methodology outlined in the 2012 XP-SWMM TBI model, watershed width was calculated by dividing the area of each subwatershed by the longest flow-path.length within the subwatershed (Figure 3). Slope was calculated using the same 30 -meter slope grid dataset used in the 2012 XP-SWMM TBI model. The average slope of each subwatershed was calculated from this dataset using zonal average data processing techniques. 2.3.4 Rainfall The Atlas 14 100 -year, 24-hour and 10 -year, 24-hour events were modeled using the National Resources Conservation Service (NRCS) MSE3 rainfall distribution. Atlas 14 depths were developed from the centroid of the watershed area. 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Where inlet control and stormsewer surcharging were possible; storage, overflow conduits, and hydraulic control structures were included to accurately account for all potential sources of overland flow to the location of flooding. 2.4.1 Stormsewer and Stormsewer Inlets As discussed in Section 2.1, stormsewer throughout the 148 -acre drainage area was digitized from as-builts, alignments, and data from two field surveys. To ensure consistency throughout the model, hydraulic parameters were generated based on methodology and data sources outlined in Section 3.3 of the 2012 TBI model report. A typical reinforced concrete pipe (RCP) Manning's roughness value of 0.013 was assumed, and entrance and exit losses assigned to each individual pipe segment were referenced from the Wurbs and James 2002 Water Resources Engineering textbook. Flared end section (FES) inlets were modeled as having grooved ends, projecting from the surrounding surface. Complex riser -outlet structures on two ponds were modeled based on measured dimensions from field surveys and received as-builts. Riser inlets were modeled as a weir and orifice in series. Modeling the outlet in this fashion ensures that weir flow is correctly controlling at low depths over the riser, and orifice flow becomes controlling as depth increases. Weir and orifice discharge coefficients were modeled consistent with the 2012 XP-SWMM TBI model. 2.4.2 Open -channels and Overflow Conduits Open -channels and overflow conduits were modeled within the project area to convey overland flow and surcharged flow from the stormsewer. Road overflows were modeled using one of two typical section geometries (modeled in XP-SWMM as natural sections). One typical road overflow type was based on the dimensions of Larpenteur Avenue West, and one was created to be typical of area -residential roads. Street flow Manning's roughness was assumed to be 0.013. Overland flow is conveyed to wet and dry ponds in several areas via rocky and earthen ditch channels. Ditch channels were modeled as trapezoidal sections in XP-SWMM based on field observation notes related to channel width, typical channel depth, and side - slope. Manning's roughness values applied to ditch channels were based on field notes related to the material composition of the ditch (e.g., large stones and cobbles, weedy earthen channel, etc.). Assumed values were then based on published roughness values listed in Bedient, Huber and Vieux 2008 Hydrology and Floodplain Analysis. 3.0 Water Quality Modeling 3.1 Hydrologic Modeling Many of the hydrologic parameters used in the P8 sediment transport model were calculated using the same methodology outlined in Section 2.0 (e.g., directly connected impervious fractions, pervious and impervious depression storage, etc.). The only hydrologic parameter calculated that was unique to the P8 water quality model was pervious Curve Number. Because P8 is designed for long-term simulation of sediment transport, hydrologic modeling is simplified by using the SCS Curve Number Method. Curve Numbers for pervious surfaces were taken from the USDA's 1986 Technical Release 55 (TR -55) Urban Hydrology for Small Watersheds. Pervious surfaces were assumed to be grass covered and in "good" conditions. Pervious Curve Number values were then based on soil type, with values of 39, 61, 74, and 80 being assigned to A, B, C, and D hydrologic soil groups, respectively. Continuous simulation was performed for a period of 30 years (1984 through 2013) using precipitation and daily average temperature data pulled from the Minneapolis -Saint Paul International Airport, 3.2 Hydraulic and Particulate Modeling The XP-SWMM model (discussed in Section 2.0) was used to generate all hydraulic data used in the P8 model. Ponds with simple outlet structures (i.e., flared end sections) were modeled as "pond" type devices with the outlet pipe diameter matching the size in the existing XP-SWMM model. Ponds with complex -riser outlet structure were modeled as "general devices", which allows for the modeling of a user -defined rating curve. Rating curves for general devices were pulled directly from the XP-SWMM model. Because P8 models sediment settling, the bathymetric volume of each pond must be entered into the model to allow for the correct calculation particulate settling and associated pollutant removal. Pond bathymetry of the two wet ponds (Gasperre Pond and Brandy Chase Pond, see Figure 2) in the study area were developed from received bathymetric as-builts, or calculated using an average depth measured in the field. Particulate properties (e.g., setline velocity, particle size fractions, event -mean contaminant concentrations, etc.) were assumed to match the NURP 50 percent (NURP50) P8 particle file. NURP50 particulate properties are assumed to be typical of urban stormwater, and are based on data collected under the EPA's Nationwide Urban Runoff Program (NURP, Athayde, 1983). 10 4.0 Modeling Results 4.1 Hydraulic Results The extent of localized flooding was evaluated by modeling the Atlas 1410- and 100 -year, 24-hour events using the XP-SWMM model described in Section 2.0. As outlined in Section 2.3.4, the cumulative depths of the 10- and 100 -year Atlas 14 design events are 4.24 and 7.43 inches, respectively. Inundation elevations of selected subwatersheds are outlined below in Table 3. Additionally, inundation areas developed from the Atlas 14 design events are shown in Figure 4. Table 3 Selected Atlas 14 design event inundation elevations Storage Atlas 14 Design Events, Overflow Max Elev. (ft) Subwatershed Description Elev.' 10 -yr, 24 -hr 100 -yr, 24 -hr CB99013 Gasperre Pond (wet pond) 941.5 942.0 942.5 CB99027 Seminary Pond (dry pond) 913.0 914.0 914.9 CB99029 Concrete swales and parking lot. 899.82 899.0 900.8 Storage overflow elevations are taken from 2011 Ramsey County LiDAR and have not been ground surveyed 2 The overflow elevation for the concrete Swale system is the low elevation along the south retaining wall adjacent to the east -west Swale. As shown in Table 3 and Figure 4, inundation of the parking lot near 1568 Eustis Street occurs during both the 10 -year and 100 -year, 24-hour events. Flooding of this parking lot has been reported to occur during moderately intense rainfall events, and the model confirms that frequent flooding of the parking lot is likely, given that the model suggests that most of the parking lot area inundates during the 10 -year, 24-hour event. Modeling of the 100 -year, 24-hour event shows that capacity issues at the concrete swale drainage system shown in Figure 1 may cause the apartment complex to the northeast to be impacted by flood inundation during that rainfall event. Survey of low -entry to the apartment complex should be collected to determine if the apartment is impacted based on the 100 -year event MWSE. The maximum water surface elevation (MWSE) within many storage subwatersheds coincides with the peak inflow rate. This suggests peak inundation elevations are driven by outflow capacity issues. Figure 5 shows where pipe capacity issues exist during the modeled 10 -year, 24-hour Atlas 14 event. Pipes displayed in red were found to be under -sized to convey the 10 -year design event. In this analysis, a pipe was considered to be undersized if the 10 -year elevation at the upstream node was either greater than the upstream node rim elevation or greater than the upstream node overflow elevation (when the upstream node represented a storage area). Capacity issues exist throughout the model area, but are particularly prevalent in the vicinity of the parking lot near 1568 Eustis Street. In the City of Lauderdale's 2008 Surface Water Management Plan (SWMP), peak outflow rates for a 100 - year, 24-hour design rainfall event are reported for several large drainage areas within the Cities of Lauderdale and Falcon Heights. Reported peak outflow rates are compared to equivalent subwatersheds from the updated modeling results presented in this technical report below in Table 4. 11 Table 4 Comparison of peak outflow rates. Subwatershed ID SA -3 2015 Eustis 2008 Street Lauderdale Regional SWMP Modeling Precipitation Frequency Estimate TP -40 Atlas 14 100 -year, 24-hour cumulative 5.9 7.43 rainfall depth (in) Subwatershed Description Seminary Pond (Dry Pond) Subwatershed ID SA -3 CB99027 Peak Outflow Rate (cfs) 46 210 Subwatershed Description Outflow from confluence of concrete swales Subwatershed ID SA -4 CB99029 Peak Outflow Rate (cfs) 95 240 Peak outflow rates reported in this updated modeling effort are much greater than those reported in the 2008 SWMP. A major reason for the difference in peak outflow rates is that the updated modeling presented in this technical report utilized precipitation frequency estimates published in NOAA Atlas 14 Volume 8 (Atlas 14), whereas the 2008 SWMP modeling effort used precipitation frequency estimates published by the U.S. Weather Bureau's Technical Paper No. 40 (TP -40). As shown in Table 4, the cumulative depth of the 100 -year, 24-hour Atlas 14 event is about 1.5 inches (-25%) greater than the TP - 40 design event. 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W N O O O O O O O O C 0 r' 0 TI a 0 -n ID m � rt Z C o _. o �m �, v o CD c� co 0 0� W -(C n m D O o Z (nn O Cl) V O J 0') QI A W N O Z O O O O O O O p 0 0 0 0 0 0 0 `° c� m0 v o 0 0 0 0 0 0 v o' D n�� �7 cn -n Wc y i i c Z CD COM (Do p o cD C o o <»` 0 o 00 0 (DD n m cn 0 <Jn a Z o cD' cn 5.0 Potential Watershed Improvements 5.1 Flood Mitigation Based on results from the uncalibrated XP-SWMM model (see Section 4.1), the apartment complex immediately northeast of the concrete swales near 1568 Eustis Street appears to be impacted by flooding during the Atlas 14 100 -year, 24-hour design event. As discussed in Section 4.1, survey of low -entry to the apartment complex is required to determine if the apartment is impacted based on the 100 -year event. Additionally, modeling in XP-SWMM indicates that parking lot near 1568 Eustis Street is partially inundated during the 10 -year and 100 -year design events (see Figure 4). To address localized flooding issues in the vicinity of the concrete swales, Barr evaluated several flood mitigation alternatives with the goal of (a) protecting the apartment complex during the 10- and 100 -year, 24-hour design events, and (b) protecting the parking lot during the 10 -year, 24-hour design event. A rating curve developed for the combined outflow from the confluence of the concrete swales (Figure 1) is shown in Figure 11. Total outflow from the confluence is the sum of outflow from the 24 -inch and 36 -inch outlet pipes at Eustis Street, as well as flow which overtops the concrete headwall and flows towards Eustis Street (overflow). In addition to the rating curve, Figure 11 also indicates at what elevation and flow rate the parking lot and apartment complex become potentially impacted, and shows the elevation and flow rate at which flow begins to overtop the headwall. As indicated in Figure 11, to protect the apartment complex, inflow to the confluence of the concrete swales must be restricted to less than 97 cfs. To protect the parking lot, inflow to the confluence must be restricted to less than 70 cfs. The existing conditions outflow hydrographs from the concrete swale system for the 10- and 100 -year design events are shown in Figure 12. As shown in Figure 12, to protect the apartment complex during the 100 -year design event, peak 100 -year outflow must be reduced by 143 cfs (60%), and to protect the parking lot during the 10 -year event, peak 10 -year outflow must be reduced by 19 cfs (21%). 21 Figure 11 Rating curve for combined outflow from the 24 -inch and 36 -inch outlet pipes at the confluence of the concrete swales. Figure 12 Existing condition outflow hydrograph from the confluence of the concrete swales. 22 500 Q Overflow 450 Q Apartment Impacted 4 400 c3 Parking Lot Impacted a, U 350 a, Rating Curve c 300 0 U 0 250 2 200 0 0 150 0 100 ~ 899.5 ft, 899.8 ft, 50 898 ft, 96.6 cfs 99.6 cfs 70.7 cfs 0 894 895 896 897 898 899 900 901 902 903 Elevation (NAVD 88, ft) Figure 11 Rating curve for combined outflow from the 24 -inch and 36 -inch outlet pipes at the confluence of the concrete swales. Figure 12 Existing condition outflow hydrograph from the confluence of the concrete swales. 22 After evaluating several design alternatives, Barr determined that to meet the stated flood mitigation design goals, several existing storage areas throughout the watershed will need to be significantly expanded to further attenuate flow. Specifically, the proposed flood mitigation alternative requires: a) construction of an earthen berm in the ravine immediately upstream of Gasperre Pond (wet pond in CB99013); b) expansion of live storage in Gasperre Pond (wet pond in CB99013); c) expansion of live storage in Seminary Pond (dry pond in CB99027); and d) expansion of live storage near the confluence of the concrete swales (CB99029). Meeting the stated flood mitigation design goal requires the cumulative storage and flow attenuation provided by the four individual projects ("a" through "d"). The four individual storage projects (Figure 13) are described in greater detail in the following subsections. 5.1.1 Earthen Berm in Ravine Over half of the total project drainage area (75 acres) drains to stormsewer along Larpenteur Avenue West between Fulham Street and Cleveland Avenue North. Flow collected by this stormsewer network discharges from a 36 -inch flared end section (FES) into a ravine located in the northeast portion of the CB99013 subwatershed (see Figure 2), which ultimately discharges to Gasperre Pond. The ravine is primarily contained in land owned by the University of Minnesota and the wet pond is owned and maintained by the City of Lauderdale. In large rain events, the peak flow rate from the existing ravine overwhelms the outlet from Gasperre Pond, causing the pond to overflow. To reduce peak flow rates through the ravine, an earthen berm could be constructed to provide additional storage and attenuate flow. The earthen berm proposed as part of the flood mitigation alternative has a maximum elevation of 961 feet (NAVD88), which provides one (1) foot of freeboard during the 100 -year event. Barr estimates that 18,500 cubic feet of suitable fill material would be required to construct the berm. To maximize flow attenuation during smaller rainfall events, Barr modeled a two-stage outlet. The proposed two-stage outlet consists of a 4 -foot diameter riser structure with an 18 -inch orifice located at the existing thalweg (bottom) elevation of the ravine. The height of the proposed 4 -foot diameter riser (958.3 feet, NAVD88) was set to be just higher than the 10 -year MWSE, which results in events up to the 10 -year event being completely controlled by the 18 -inch orifice at the thalweg, with events greater than the 10 -year event discharging into the 4 -foot diameter riser. The orifice and 4 -foot diameter riser discharge to a 24 -inch pipe, which has sufficient capacity to pass events as large as the 100 -year design storm while maintaining 1 -foot of freeboard to the top elevation of the berm. Table 6 compares the maximum storage volume and peak flow rate from the proposed earthen berm to existing conditions and shows that the storage provided by the earthen berm reduces peak flow rate to Gasperre Pond by 30 percent during the 100 -year design event, and nearly 20 percent during the 10 -year event. 23 While this alternative does not achieve the study's flood mitigation goals without a combination of other alternatives (Section 5.1.6), Table 10 shows the flood mitigation benefit achieved at the east -west swale by implementing this alternative alone. Table 6 Storage and peak flow comparison at the proposed earthen berm. Max Storage (ac -ft) Peak Flow (cfs) 10 -year 100 -year 10 -year 100 -year Existing Condition - -- 59.7 75.6 Flood Mitigation Alt. 2.36 3.28 40.4 62.1 Difference (%) I -- I -- 1 -32% 1 -18°% 5.1.2 Expansion of Gasperre Pond (CB99013) Gasperre Pond (the existing wet pond in subwatershed CB99013, see Figure 2), owned and maintained by the City of Lauderdale, has a tributary drainage area of 104 acres (over 70 percent of the entire study area). Even with the flow attenuation provided by the proposed earthen berm, Gasperre Pond will need to be expanded to prevent overflow events and reduce peak flow rate to downstream storage areas (i.e., Seminary Pond and the confluence of the concrete swales). Barr modeled an increase in the live storage (i.e., available storage above the permanent pool) in Gasperre Pond by widening the pond and raising the elevation of the hiking trail along the south side of the pond. By grading the pond from the existing overflow elevation (941.5 feet, NAVD88) to the existing pond bottom elevation (931.66 feet, NAVD88), live storage can be increased by nearly 12,500 cubic feet (0.3 acre-feet). By raising the elevation of the hiking trail along the south side of the pond to 945.5 feet (NAVD88), live storage can be increased by an additional 4 acre-feet. Barr estimates that raising the elevation of the hiking trail would require over 4,000 cubic feet of fill material. In addition to increasing the volume of Gasperre Pond, Barr modeled a two-stage outlet (similar to the outlet proposed for the earthen berm) to maximize flow attenuation. The two-stage outlet modeled consists of a 5 -foot diameter riser structure with a 27 -inch orifice at the existing permanent pool elevation (934.84 feet, NAVD88). The height of the riser, 940.5 feet (NAVD88), was set to bejust higher than the 2 -year design event (meaning events as large as the 2 -year event would be controlled by the 27 -inch orifice). The orifice and riser discharge to a 30 -inch outlet pipe, which has sufficient capacity to pass the 100 -year design event while maintaining 1 -foot of freeboard to the proposed top of the hiking trail. Table 7 compares the maximum storage volume and peak flow rate from the proposed expansion of Gasperre Pond to existing conditions and shows that increasing live storage reduces peak outflow rate during the 10 -year and 100 -year events. While this alternative does not achieve the study's flood mitigation goals without a combination of other alternatives (Section 5.1.6), Table 10 shows the flood mitigation benefit achieved at the east -west swale by implementing this alternative alone. 24 Table 7 Storage and peak flow comparison at the proposed expansion of Gasperre Pond. Max Storage (ac -ft) Peak Flow (cfs) 10 -year 100 -year 10 -year 100 -year Existing Condition 1 4.27 4.72 75.8 1 151.8 Flood Mitigation Alt.' 4.37 6.01 54.9 93.7 Difference M +2% +27% -28% -38% Reflects the combined hydraulic impact of the four projects discussed in Sections 5.1.1, 5.1.2, 5.1.3, and 5.1.5. 5.1.3 Expansion of Seminary Pond and Sheet Pile Wall (CB99027) In addition to the proposed earthen berm in the ravine and expansion of Gasperre Pond, Seminary Pond (the dry pond owned by Luther Seminary in subwatershed CB99027, see Figure 2) would need to be expanded to provide additional storage and flow attenuation. Seminary Pond receives flow from the upstream ravine and Gasperre Pond, a portion of the housing development between Larpenteur Avenue West and Idaho Avenue, and a small residential area to the southeast between Fulham Street and Northrop Ave (128 acres, 87 percent of the total study area). Barr modeled an increase in live storage in Seminary Pond by widening the pond and constructing a sheet pile wall to increase the overflow elevation by 6.5 feet. By grading the pond from the existing overflow elevation (913 feet, NAVD 88) to the existing pond bottom elevation (904.35 feet, NAVD 88), available storage can be increased by over 130,500 cubic feet (3.0 acre-feet). By constructing a sheet pile wall along the west face of the pond at an elevation of 919.6 feet, storage can be increased by an additional 6.3 acre- feet. Barr estimates that nearly 5,000 square feet of sheet pile would be required to construct the proposed sheet pile wall. Similar to the proposed earthen berm and expansion of Gasperre Pond, Barr modeled a two-stage outlet. The modeled two-stage outlet consists of a 5 -foot diameter riser structure with a 24 -inch orifice at the existing pond bottom elevation. The elevation of the riser (910.6 feet, NAVD88) was established to bejust higher than the 2 -year event MWSE (ensuring events as large as the 2 -year event are controlled by the 24 -inch orifice). The orifice and riser discharge to a 30 -inch outlet pipe which has sufficient capacity to pass the 100 -year event with 1 -foot of freeboard below the proposed sheet pile wall top elevation. As shown in Figure 13, the proposed 30 -inch outlet pipe requires that all stormsewer infrastructure downstream be increased from 24 -inch (existing) to 30 -inch diameter pipe. Table 8 compares the maximum storage volume and peak flow rate from the proposed expansion of Seminary Pond to existing conditions. As can be seen, increasing storage in the dry pond significantly reduces peak outflow rate during the 10 -year and 100 -year event. While this alternative does not achieve the study's flood mitigation goals without a combination of other alternatives (Section 5.1.6), Table 10 shows the flood mitigation benefit achieved at the east -west swale by implementing this alternative alone. While a wetland delineation has not been performed for Seminary Pond, Barr staff observed wet soils and other indications that wetlands may exist in this location. Additionally, the City of Lauderdale's 2008 Local 25 Surface Water Management Plan indicates that a portion of the pond is a seasonally -flooded wetland. Before any design work that would involve excavation in Seminary Pond, Barr recommends performing a wetland delineation to determine what areas of Seminary Pond may be wetlands, if any, to aid in the design in order to mitigate or prevent wetland impacts. Table 8 Storage and peak flow comparison at the proposed expansion of Seminary Pond and sheet pile wall. Max Storage (ac -ft) Peak Flow (cfs) 10 -year 100 -year 10 -year 100 -year Existing Condition 2.99 3.85 86.5 1 210.2 Flood Mitigation Alt.' 4.54 11.58 57.3 1 79.0 Difference N +52% +201% -34% -625%1. Reflects the combined hydraulic impact of the four projects discussed in Sections 5.1.1, 5.1.2, 5.1.3, and 5.1.5. 5.1.4 Expansion of Seminary Pond and Earthen Berm (CB99027) The 10 -year flood mitigation goal can be achieved by expanding storage of Seminary Pond (Figure 2). As discussed in Section 5.1.3, nearly 90 percent of the total study area (128 acres) drains through the dry pond owned by Luther Seminary. To meet the 10 -year flood mitigation goal, storage in the pond will need to be increased to prevent overflow and reduce peak flows during the 10 year event. Barr modeled an increase in live storage in Seminary Pond by widening the pond and constructing an earthen berm to increase the overflow elevation by 2.5 feet. By grading the pond from the existing overflow elevation (913 feet, NAVD 88) to the existing pond bottom elevation (904.35 feet, NAVD 88), available storage can be increased by over 130,500 cubic feet (3.0 acre-feet). By constructing an earthen berm along the west face of the pond at an elevation of 915.5 -feet, storage can be increased by an additional 2.3 acre-feet. Barr estimates that constructing the earthen berm would require nearly 1,900 cubic feet of fill material. Barr designed this flood mitigation alternative to meet the 10 -year flood mitigation goal (i.e., protect the apartment complex parking lot during the 10 -year design event) using the existing outlet (24 -inch FES) and based on the existing downstream and upstream stormwater infrastructure. The elevation of the earthen berm (915.5 feet, NAVD 88) was based on the elevation required to completely retain the 10 -year design event. In addition to constructing an earthen berm and converting Seminary Pond into a wet pond, Barr recommends constructing an iron -enhanced sand filter (IESF) bench to enhance dissolved phosphorus removal. The water quality components of this design are discussed further in Section 5.2.3. Table 9 compares the maximum storage volume and peak flow rate from the proposed expansion of Seminary Pond to existing conditions. As can be seen, increasing storage in the dry pond significantly reduces peak outflow rate during the 10 -year event, but has less significant impact on peak outflow during the 100 -year event. This alternative does not achieve the study's flood mitigation goals without further flood mitigation improvements upstream or downstream in the watershed. Table 10 shows the flood mitigation benefit achieved at the east -west swale by implementing this alternative alone. 26 While a wetland delineation has not been performed for Seminary Pond, Barr staff observed wet soils and other indications that wetlands may exist in this location. Before any design work that would involve excavation in Seminary Pond, Barr recommends performing a wetland delineation to determine what areas of Seminary Pond may be wetlands, if any, to aid in the design to mitigate or prevent wetland impacts. Table 9 Storage and peak flow comparison at the proposed expansion of Seminary Pond and earthen berm. Max Storage (ac -ft) Peak Flow (cfs) 10 -year 100 -year 10 -year 100 -year Existing Condition 2.99 3.85 86.5 210.2 Flood Mitigation Alt. 8.81 10.74 42.5 166.6 Difference (%) 1 +195% 1 +179% 1 -51% 1 -21% 1 5.1.5 Expansion of Storage at Confluence (CB99029) Based on the existing conditions XP-SWMM model, if it were possible to increase storage in Gasperre Pond and Seminary Pond sufficiently to completely eliminate outflow from these areas, the parking lot would still become partially inundated during the 10 -year design event based solely on inflow from the northwestern portion of the study area (the "untreated" area shown in Figure 8). For this reason, Barr modeled an increase in storage in the existing concrete and grass swale area (owned by Waste Management) to attenuate flows from the northwestern portion of the watershed (see Figure 13). By grading from the edge of the parking lot to the pipe invert elevation at the confluence (894.5 feet, NAVD88), it is possible to increase storage in this area by nearly 0.5 acre-feet. Barr determined that this volume is sufficient to prevent the peak flow from the northwestern portion of the watershed from impacting the parking lot, in combination with other flood mitigation alternatives (Section 5.1.6). While this alternative does not achieve the study's flood mitigation goals without a combination of other alternatives (Section 5.1.6), Table 10 shows the flood mitigation benefit achieved at the east -west swale by implementing this alternative alone. 5.1.6 Combined Flood Mitigation Alternative The impact of each of flood mitigation alternatives discussed in Sections 5.1.1 through 5.1.5 on maximum water surface elevation (MWSE) and outflow at the confluence of the swales is summarized in Table 10. The maximum outflow and MWSE allowed achieving the stated flood mitigation design goals of (a) protecting the apartment complex during the 10- and 100 -year, 24-hour design events, and (b) protecting the parking lot during the 10 -year, 24-hour design event are shown as the "Protection Goal" targets in this table. As can be seen, none of the individual flood mitigation alternatives described in Sections 5.1.1 through 5.1.5 meet the 10 -year or 100 -year design goals. However, when the alternatives presented in Sections 5.1.1, 5.1.2, 5.1.3, and 5.1.4 are considered in combination (see "Combined Flood Mitigation Alternative" in Table 10), both the 10- and 100 -year design goals are met. The alternative 27 discussed in Section 5.1.4 (expansion of Seminary Pond and earthen berm) meets the 10 -year design goal of protecting the parking lot, but not the 100 -year design goal of protecting the apartment complex. Table 10 Flood mitigation alternative hydraulic summary. Maximum allowed outflow and MWSE to meet the stated design protection goals (protect the parking lot during the 10 -year event; protect the apartment complex during the 100 -year event). MWSE at the confluence of the concrete swales near 1568 Eustis Street. The resulting 10- and 100 -year event hydrographs from the combination of the four storage options discussed in Sections 5.1.1, 5.1.1, 5.1.2, 5.1.3, and 5.1.5 ("combined flood mitigation alternative") and the alternative discussed in Section 5.1.4 ("expansion of Seminary Pond and earthen berm") are shown in Figure 14 and Figure 15, respectively. The figures show that the combined attenuation from the four storage projects protects the apartment during the 100 -year event and the parking lot during the 10- and 100 -year events, and that the alternative discussed in Section 5.1.4 protects the parking lot during the 10 - year design event. Table 11 summarizes the planning level capital cost and annualized cost of the five storage projects discussed in Sections 5.1.1 through 5.1.5. The capital costs include estimated construction and engineering costs, as well as a 30 percent contingency to reflect construction elements not identified at the conceptual level. 28 MWSE at Confluence Peak Flow (cfs) (ft, NAVD88)' Model Scenario 10 -year 100 -year 10 -year 100 -year Protection Goal' 70.73 96.60 898 899.5 Existing Conditions 89.77 239.86 898.98 900.83 Alt. 1. Earthen Berm in Ravine 74.68 166.34 898.14 900.44 Alt. 2. Expansion of Gasperre Pond 87.82 186.17 898.85 900.56 Alt. 3A. Expansion of Seminary Pond and 70.14 106.14 897.99 899.97 Sheet Pile Wall Alt. 3B. Expansion of Seminary Pond and 65.32 182.53 897.86 900.54 Earthen Berm Atl 4. Expansion of Storage at Confluence 89.00 239.68 898.93 900.83 Combined Flood Mitigation Alternative: 63.76 95.81 897.79 899.42 Alternatives 1, 2, 3A, and 4 Maximum allowed outflow and MWSE to meet the stated design protection goals (protect the parking lot during the 10 -year event; protect the apartment complex during the 100 -year event). MWSE at the confluence of the concrete swales near 1568 Eustis Street. The resulting 10- and 100 -year event hydrographs from the combination of the four storage options discussed in Sections 5.1.1, 5.1.1, 5.1.2, 5.1.3, and 5.1.5 ("combined flood mitigation alternative") and the alternative discussed in Section 5.1.4 ("expansion of Seminary Pond and earthen berm") are shown in Figure 14 and Figure 15, respectively. The figures show that the combined attenuation from the four storage projects protects the apartment during the 100 -year event and the parking lot during the 10- and 100 -year events, and that the alternative discussed in Section 5.1.4 protects the parking lot during the 10 - year design event. Table 11 summarizes the planning level capital cost and annualized cost of the five storage projects discussed in Sections 5.1.1 through 5.1.5. The capital costs include estimated construction and engineering costs, as well as a 30 percent contingency to reflect construction elements not identified at the conceptual level. 28 ;,. A. A,ri,... mD_^mD my ;��v ;� (DZ) "(D� w o (n W o (n D 3 3 w w m m O o D 3 a. 0- w w w O 7 Q- Q w � D 3 v Q AY G kil t mD_^mD my ;��v ;� (DZ) "(D� w o (n W o (n D 3 3 w w m m O o D 3 a. 0- w w w O 7 Q- Q w � D 3 v 1101.°1® w m m w m m m m C: x v =r x x o 0 � w m � Et _0 _0 DO <5 = 0 w 7 -u (o (Q 0 (D (U o 0o m cn Cn o- CL =r o o cn � CD 0 'n 9 9 Q O 3 3 3 O 0" O W(n c 3 3 O o 3 N(D cD Q � (D 0 w (D ' C C' m w 0 -n � r cD Dr O 1 cQ � -, O 0 m 0 5. C7 c� W �CL (DO W +'0 co)00 (D `D m > m cf)O Z 0 0 1101.°1® w m m w m m m m C: x v =r x x o 0 � w m � Et _0 _0 DO <5 = 0 w 7 -u (o (Q 0 (D (U o 0o m cn Cn o- CL =r o o cn � CD 0 'n 9 9 Q O 3 3 3 O 0" O W(n c 3 3 O o 3 N(D cD Q � (D 0 w (D ' C C' m w 1CA - 10 -year design event Existing Condition 200 Combined flood mitigation alternative Conversion of Seminary Pond to wet pond with IESF and earthen berm Parking Lot Impacted --- Apartment Impacted 150 — -Overflow T u 3 0 " 100 — — — — — — — — — —XN— — — — — — — — — — 50 0 0:00 3:00 6:00 9:00 12:00 15:00 18:00 21:00 0:00 Time Figure 14 Existing condition compared to combined flood mitigation alternative for 10 -year design event. 100 -year design event Existing Condition 200 _ Combined flood mitigation alternative Conversion of Seminary Pond to wet pondL m Parking Lot Impacted 150 --- Apartment Impacted Overflow u 3 0 100 _ __ --- — — — — — — — — — — — — — — — — 50 0 0:00 3:00 6:00 9:00 12:00 15:00 18:00 21:00 0:00 Time Figure 15 Existing condition compared to combined flood mitigation alternative for 100 -year design event. 30 N a cd+� o N 00 0 o 00 0 o 0 C, C H 0fA- ' N OD O O o CDo CD O C a N 00 CD O ON O OD O O O O O ppLK N Ln O O M IK N o 0 0 0 00 0 0 0 0 0 0 0 0 0 o U 00 i n civ c� CD 0 0 0 0 0 +� 0 O O N oo c O O O O o O W 0 P. p O M O C� O c\i CD O o O C EiUV o - 00oo a� 44 o o a U y o 0 CD 0 O 0 0 r O O O O O O u O O p v C o 0 u U U a maj y U m' cl C by o a v Wcn �� a WU a U o�� b b M_ p rte+ ir' O s`p'a r -11M N O z cV N L)ON c u p 'off W C� SFAP� -a C%U uorido uoR,-2pTj/\j pool d PaLr[quzoD 5.2 Water Quality Using the uncalibrated water quality model (see Section 3.0), Barr evaluated the water quality impacts of several potential best management practices (BMPs) through the study area. Individual BMPs are discussed and evaluated in the following subsections. 5.2.1 Redevelopment of Gasperre Pond (CB99013) Analysis of Gasperre Pond in subwatershed CB99013 (Section 4.2) showed that the wet pond does not meet the NURP annual pollutant removal criteria of 80 percent TSS removal and 60 percent TP removal. Due to the large drainage area to this pond, Barr determined that it is not possible to achieve the NURP removal criteria through excavation and expansion of the pond alone. For this reason, Barr recommends that the water quality performance of the feature be improved by expanding and deepening the pond and installing an iron -enhanced sand filter (IESF). By grading the pond from the existing overflow elevation (941.5 -feet, NAVD 88) to 1.8 feet below the existing pond bottom elevation (929.84 feet, NAVD88), live storage can be increased by nearly 30,500 cubic feet (0.7 acre-feet). Based on this proposed grading, Barr determined that an IESF bench could be constructed along the west and north edge of the proposed pond, creating a total IESF area of 1,280 -feet. To maintain a drawdown time of 48 -hours, the IESF bench would be constructed at an elevation of 934.22 feet NAVD88 (0.6 feet lower than the existing normal water level of the pond). Pollutant removal from the proposed redevelopment of the wet pond is compared to existing conditions in Table 12. As can be seen, pollutant removal provided by the expanded pond storage and infiltration bench is much closer to NURP removal criteria. Table 12 Annual TSS and TP reduction from proposed redeveloped of Gasperre Pond. 5.2.2 Conversion of Seminary Pond to Wet Pond (CB99027) Analysis of the water quality performance of Seminary Pond in subwatershed CB99027 showed that the pond is providing limited pollutant load removal (12 percent removal of TSS and two percent removal of TP, see Table 5). To improve the water quality performance of this feature, Barr recommends expanding storage in the pond, and converting the dry pond into a wet pond. By grading the pond from the existing overflow elevation (913 feet, NAVD88) to three feet below the existing pond bottom elevation (901.35 feet, NAVD88), storage in the pond can be increased by nearly 200,000 cubic feet (4.45 acre-feet). Maintaining the same outlet structure (FES at an elevation of 904.35 feet NAVD88), this expansion would provide nearly 1.5 acre-feet of permanent pool volume. 32 Load Reduction (lbs/yr) Load Reduction (%) Pond ID Description TSS TP TSS TP Existing Condition 6,760 11.4 56% 29% CB99013 Proposed Expansion and Fe- Enhanced Filtration Bench 7,454 15.4 61% 39% Difference 694 4.0 +6% +10% 5.2.2 Conversion of Seminary Pond to Wet Pond (CB99027) Analysis of the water quality performance of Seminary Pond in subwatershed CB99027 showed that the pond is providing limited pollutant load removal (12 percent removal of TSS and two percent removal of TP, see Table 5). To improve the water quality performance of this feature, Barr recommends expanding storage in the pond, and converting the dry pond into a wet pond. By grading the pond from the existing overflow elevation (913 feet, NAVD88) to three feet below the existing pond bottom elevation (901.35 feet, NAVD88), storage in the pond can be increased by nearly 200,000 cubic feet (4.45 acre-feet). Maintaining the same outlet structure (FES at an elevation of 904.35 feet NAVD88), this expansion would provide nearly 1.5 acre-feet of permanent pool volume. 32 Pollutant removal from the proposed wet pond in subwatershed CB99027 is compared to the existing conditions Table 13. Expanding available storage and deepening the pond to create a permanent pool increases TSS and TP removal by 2,643- and 7.4 -pounds per year, respectively. While a wetland delineation has not been performed for Seminary Pond, Barr staff observed wet soils and other indications that wetlands may exist in this location. Before any design work that would involve excavation in the dry pond, Barr recommends performing a wetland delineation to determine what areas of Seminary Pond may be wetlands, if any, to aid in the design to mitigate or prevent wetland impacts. Table 13 Annual TSS and TP reduction provided by conversion of Seminary Pond to wet pond. 5.2.3 Conversion of Seminary Pond to Wet Pond with IESF (CB99027) As discussed in Section 5.2.2, converting Seminary Pond in subwatershed CB99027 into a wet pond improves pollutant removal significantly. To further improve the water quality performance of this proposed design, Barr evaluated the impact of expanding the storage in this area by constructing an IESF bench on two sides of the proposed wet pond. Note that the excavation required to convert the dry pond into a wet pond is described above in Section 5.2.2. Based on the proposed excavation and grading, Barr determined that an IESF bench could be constructed along the north and south edge of the proposed pond, creating a total IESF area of 1,500 square feet. To maintain a drawdown time of 48 -hours, the IESF bench would be constructed at an elevation of 904.44 feet NAVD88 (0.5 feet lower than the existing normal water level of the pond). Pollutant removal from the proposed wet pond and IESF in CB99027 is compared to existing conditions in Table 14. As can be seen, pollutant removal provided by the expanded pond storage and infiltration bench is closer to NURP removal criteria. The alternative presented (i.e., conversion of Seminary Pond to wet pond with IESF) is one of several alternatives evaluated in subwatershed CB99027. Depending on local soils, it may be possible to convert Seminary Pond into a dry filtration or infiltration basin. For this reason Barr recommends that soil samples be taken within the basin to assess the feasibility of filtration or infiltration using local soils. 33 Load Reduction (lbs/yr) Load Reduction (%) Pond ID Description TSS TP TSS TP CB99013 Seminary Pond (existing conditions) 1,180 0.6 12% 2% Proposed Wet Pond 3,824 8.0 38% 19% Difference 2,643 7.4 +26% +17% 5.2.3 Conversion of Seminary Pond to Wet Pond with IESF (CB99027) As discussed in Section 5.2.2, converting Seminary Pond in subwatershed CB99027 into a wet pond improves pollutant removal significantly. To further improve the water quality performance of this proposed design, Barr evaluated the impact of expanding the storage in this area by constructing an IESF bench on two sides of the proposed wet pond. Note that the excavation required to convert the dry pond into a wet pond is described above in Section 5.2.2. Based on the proposed excavation and grading, Barr determined that an IESF bench could be constructed along the north and south edge of the proposed pond, creating a total IESF area of 1,500 square feet. To maintain a drawdown time of 48 -hours, the IESF bench would be constructed at an elevation of 904.44 feet NAVD88 (0.5 feet lower than the existing normal water level of the pond). Pollutant removal from the proposed wet pond and IESF in CB99027 is compared to existing conditions in Table 14. As can be seen, pollutant removal provided by the expanded pond storage and infiltration bench is closer to NURP removal criteria. The alternative presented (i.e., conversion of Seminary Pond to wet pond with IESF) is one of several alternatives evaluated in subwatershed CB99027. Depending on local soils, it may be possible to convert Seminary Pond into a dry filtration or infiltration basin. For this reason Barr recommends that soil samples be taken within the basin to assess the feasibility of filtration or infiltration using local soils. 33 Table 14 Annual TSS and TP reduction provided by conversion of Seminary Pond to wet pond with IESF and earthen berm. 5.2.4 Residential Rain Gardens Barr evaluated the potential to add water quality treatment BMPs in the untreated northwest portion of the study area (see Figure 8). Based on the likely available greenspace in this area and the steep gradient along Eustis Street between Larpenteur Avenue W and Como Avenue, there is limited potential to add water quality treatment features in this portion of the watershed. Along Carl Street, two residences were identified as having sufficient available yard area to construct raingardens to treat runoff from adjacent streets (see Figure 16). The two raingardens were sized based on Minnesota Pollution Control Agency's (MPCA) Minimal Impact Design Standards (MIDS), and water quality performance of the two features was analyzed using the MPCA's MIDS Calculator. The rain gardens were modeled as infiltrating features and a saturated infiltration rate typical of Hydrologic Soil Group (HSG) B soils was assumed. Information related to rain garden sizing and pollutant removal from the proposed rain gardens at 1707 Carl Street and 1701 Carl Street are shown in Table 15 and Table 16, respectively. Table 15 Residential rain garden sizing. Load Reduction (lbs/yr) Load Reduction (%) Pond ID Description TSS TP TSS TP 0.90 Existing Condition 1,180 0.6 12% 2% CB99013 Conversion of Seminary Pond to Wet Pond w/ IESF and Earthen Berm 5,519 17.5 54% 41% 1707 Carl Street Difference 4,338 16.9 +43% +40% 5.2.4 Residential Rain Gardens Barr evaluated the potential to add water quality treatment BMPs in the untreated northwest portion of the study area (see Figure 8). Based on the likely available greenspace in this area and the steep gradient along Eustis Street between Larpenteur Avenue W and Como Avenue, there is limited potential to add water quality treatment features in this portion of the watershed. Along Carl Street, two residences were identified as having sufficient available yard area to construct raingardens to treat runoff from adjacent streets (see Figure 16). The two raingardens were sized based on Minnesota Pollution Control Agency's (MPCA) Minimal Impact Design Standards (MIDS), and water quality performance of the two features was analyzed using the MPCA's MIDS Calculator. The rain gardens were modeled as infiltrating features and a saturated infiltration rate typical of Hydrologic Soil Group (HSG) B soils was assumed. Information related to rain garden sizing and pollutant removal from the proposed rain gardens at 1707 Carl Street and 1701 Carl Street are shown in Table 15 and Table 16, respectively. Table 15 Residential rain garden sizing. Table 16 Annual water load, TSS, and TP reduction provided by residential rain gardens. Tributary Area (ac) Treatment Volume (cf) Average Depth (ft) Top Area (sf) Subwatershed Location Total Area Impervious Area 1707 Carl Street 0.90 0.18 713 1.2 749 CB99022 1701 Carl Street 1.04 0.21 829 1.2 857 Table 16 Annual water load, TSS, and TP reduction provided by residential rain gardens. 34 Pollutant Load Pollutant Load Reduction (lbs/yr) Reduction (%) Water Load Subwatershed Location Reduction (cf/yr) TSS TP TSS TP 1707 Carl Street 713 84 0.46 75% 75% CB99022 1701 Carl Street 829 97 0.53 75% 75% 34 f7 0 N 0 T C: v D - (D n. cu 0 v v CL (D r 0 0 v 0 cQ mDm o Z Uj ��� >m,(D m z CD ;(1 N al �CD(DM Z1 (J, N 0 T C: v D - (D n. cu 0 v v CL (D r 0 0 v 0 5.2.5 BMP Cost and Cost -Benefit Planning level capital cost, annualized cost, and cost -benefit of each of the BMPs evaluated in Sections 5.2.1 through 5.2.4 are compared below in Table 17. The capital costs include estimated construction and engineering costs, as well as a 30 percent contingency to reflect construction elements not identified at the conceptual level. As noted in Table 17, the cost -benefit analysis of water and pollutant load reduction is based on the net reduction from each proposed options. For example, if a feature is being expanded or converted, the load reduction considered in the cost -benefit analysis is the increase in load reduction from the existing to the proposed condition. 36 n O rt CT D (D v v to v V) CD O_ O 7 S (D 7 (D r -r 7� n rD v ED ED h v Q 0 C r -r v 7 -r O v Q O 3 O -e, O 3 (D (D X L r -r O 3 (D 'O O O O 0- 0 O Q o' p C-)� o p Q' o' tT rs oP r -- D N rN N CD W r J rs �7 rt O GS CD a (D a (D a �0 (Co 0 n � b 10 � � R. c R. - - fD 0 rt c rtte(D ^^ //��1 O n r r• 177 W H b r- ~ � � G (D O O O 0.3 t _ r R- � p � a COj 0 a' rD rt Pn a, m N N cn � O O O O O O O O rt n O O O O O 3 N J n N O 0 0 0 0 0 0 0 0 CD o 0 - n O O o 0 w LQ + CD W w n 0 0 0 0 0CDo 0 00 CD 0 0 0 0 n� O O O O O O A� r F. Y, N � C O lV O O O rt O 00 O �+ N tQ IQny N Oo O tQ 41 p O O O O C:) O O O r- �9 \ �.I b M z Z N N .ry CD p.�� O O AD Q+ O rr rD m 'C \ CLn a �, o c a o 0 0 0 0 CD C n 0 0 0 o O w ap,o C 6.0 Recommendation Based on the flood mitigation and water quality alternatives presented in Sections 5.1 and 5.2, Barr has identified that a combination of alternatives targeted at Seminary Pond (the dry pond in subwatershed CB99027, see Figure 2) would be most cost-efficient in achieving flood mitigation goals and producing water quality benefits. Specifically, Barr recommends that the flood mitigation alternative outlined in Section 5.1.4 (expansion of Seminary Pond and earthen berm) be combined with the water quality alternative presented in Section 5.2.3 (conversion of Seminary Pond to wet pond with IESF). By grading the pond from the existing overflow elevation (913 feet, NAVD88) to three feet below the existing pond bottom elevation (901.35 feet, NAVD88), storage in the pond can be increased by nearly 200,000 cubic feet (4.45 acre-feet). Maintaining the same outlet structure (FES at an elevation of 904.35 feet NAVD88), this expansion would provide nearly 1.5 acre-feet of permanent pool volume. Constructing an earthen berm along the west face of the pond at an elevation of 915.5 feet NAVD88 and expanding the storage area as shown on Figure 13 increases live storage by an additional 2.3 acre-feet, and ensures that the 10 -year design event is completely contained without overtopping the berm. In additional to the proposed excavation and earthen berm, Barr recommends that an IESF be constructed along the north and south edge of the proposed pond to provide a total filter area of 1,500 square feet. To maintain a drawdown time of 48 -hours, the IESF bench would be constructed at an elevation of 904.44 feet NAVD88 (0.5 feet lower than the existing normal water level of the pond). A schematic of the proposed berm, pond excavation, and IESF is shown in Figure 17. 925 Outlet (Existing 24" FES) - - Existing Berm and Pond Surface --- Proposed Berm and Pond Grading 920 ...... Proposed Normal Pool 00 0 IESF Elevation z 915 a / a / 0 910 ♦ / j a LU / 905 .............................................../ -------------------------� 900 0 50 100 150 200 250 300 350 Profile Length (ft) Figure 17 Profile: Seminary Pond expansion and conversion to wet pond. 38 Planning level capital cost, annualized cost, and cost -benefit of the combine flood mitigation and water quality alternative is shown in Table 18. In addition to the water quality cost -benefit analysis shown in Table 18, the proposed alternative has the additional benefit of meeting the 10 -year event protection goal (i.e., protecting the parking lot during the 10 -year, 24-hour design event). The hydraulic impact of the proposed alternative is identical to the hydraulic impact of the alternative discussed in Section 5.1.4 (expansion of Seminary Pond and earthen berm) as outlined in Table 9 and Table 10. As noted in Table 10, the proposed alternative does not meet the protection goal for the 100 -year event (i.e., protect the apartment complex during the 100 -year design event). As discussed in Section 5.1.6, only the combination of the four flood mitigation alternatives discussed in Sections 5.1.1, 5.1.2, 5.1.3, and 5.1.5 was shown to meet the 100 -year event protection goal. In addition to the flood mitigation and water quality improvements at Seminary Pond, Barr recommends pursuing the installation of a rain garden at either 1701 or 1707 Carl Street. The two proposed gardens would treat essentially the same drainage area, so there is no need to install rain gardens at both locations. Table 18 displays the cost benefit information for this alternative. As next steps, Barr recommends: • Performing soil borings on top of the existing berm and in the proposed excavation area to determine the infiltration capacity of the soils and the geotechnical stability of the berm. • Performing a wetland delineation of Seminary Pond to determine the permitting feasibility of excavating Seminary Pond for an IESF and permanent pool. • Contact the homeowners and pursue a rain garden installation at EITHER 1701 or 1707 Carl Street. 39 v Q v f+ n O O Z) CD D 0 0 0 LA Q 3 O 3 h 41 0 o o CD o `�° rry ' Q G rt N rD N J N �. 0 C/Oa m a Cf)o o n y 0 o O 0 0 0 0 0 0 0 0 n WIQ CD o CD N O C o O O O O O rt n u 0 0 0 0 Fd Ln O O o P? H c� a 0 0 o 0 d' 0 m CD a, O O p o a rt O O O Go IQ 0 0 cn c, rD eD K rn n P. p. rt 'd 7pl tQ V, O 0 0 0 K ap.o �cn 00 7.0 References Athayde. 1983. United States Environmental Protection Agency's Nationwide Urban Runoff Program (NURP). Bedient, Huber and Vieux. 2008. Hydrology and Floodplain Analysis. Lauderdale, City of. 2008. Surface Water Management Plan (SWMP). United States Department of Agriculture. 1986. Technical Release 55 (TR -55) Urban Hydrology for Small Watersheds. United States Department of Agriculture. 1961. Rainfall Frequency Atlas of the United States. Technical Paper No. 40. United States Environmental Protection Agency. 1988. Storm Water Management Model; Version 4 User's Manual. Wurbs and James. 2002, Water Resources Engineering. 41 Appendix Table A Subwatershed hydrologic parameter summary. 42 Horton Infiltration Parameters SWS ID Area (ac) Slope (%) Width (ft) Impervious Area (%) Directly Connected Impervious Area (%) Max.lnf. Rate (in/hr) Min.lnf. Rate (in/hr) Infiltration decay rate (s-1) AP115 2.9 2.88% 296.92 13% 10% 3.000 0.230 0.00115 CB101 0.54 1.49% 41.07 54% 43% 3.000 0.230 0.00115 CB105B 0.62 2.23% 105.65 55% 50% 3.000 0.230 0.00115 CB112 1.42 3.21% 135.53 42% 42% 3.000 0.230 0.00115 CB143A 9.6 1.87% 305.1 1% 0% 3.000 0.230 0.00115 CB1536 0.23 1.98% 40.04 70% 70% 3.000 0.230 0.00115 CB99001 1.93 1.88% 169.91 63% 51% 3.000 0.230 0.00115 CB99002 0.59 0.99% 88.43 36% 19% 3.000 0.230 0.00115 CB99003 3.05 2.46% 276.75 18% 8% 3.000 0.230 0.00115 CB99004 6.4 3.72% 442.25 6% 0% 3.000 0.230 0.00115 CB99006 4.24 3.20% 251.9 33% 20% 3.000 0.230 0.00115 CB99007 7.6 4.29% 503.83 14% 1% 3.000 0.230 0.00115 CB99008 0.52 5.90% 125.12 38% 37% 3.000 0.230 0.00115 CB99009 0.96 6.53% 143.24 35% 27% 3.000 0.230 0.00115 CB99010 2.86 4.59% 188.51 28% 14% 3.000 0.230 0.00115 CB99011 4.1 6.88% 381.53 24% 12% 3.000 0.230 0.00115 CB99012 1.74 5.55% 152.69 39% 26% 3.000 0.230 0.00115 CB99013 12.87 7.66% 340.09 8% 2% 2.898 0.217 0.00115 CB99014 7.09 2.90% 436.96 41% 28% 3.000 0.230 0.00115 CB99015 1.52 3.38% 127.36 30% 26% 3.000 0.230 0.00115 CB99016 0.4 3.93% 107.73 10% 0% 3.000 0.230 0.00115 CB99017 0.43 2.43% 81.67 9% 5% 2.672 0.187 0.00115 CB99018 1.23 1.41% 134.48 24% 12% 2.986 0.228 0.00115 CB99019 0.89 5.27% 112.07 20% 10% 3.000 0.230 0.00115 CB99020 2.35 4.91% 212.57 43% 31% 2.454 0.159 0.00115 CB99021 0.42 4.63% 91.16 36% 21% 2.678 0.188 0.00115 CB99022 5.21 2.04% 316.92 20% 8% 3.000 0.230 0.00115 CB99023 1.5 2.37% 160.15 16% 0% 3.000 0.230 0.00115 CB99024 4.55 7.85% 297.49 70% 62% 3.000 0.230 0.00115 CB99025 1.9 7.46% 172.16 91% 74% 3.000 0.230 0.00115 CB99026 3.59 6.29% 263.61 53% 42% 2.905 0.218 0.00115 CB99027 8.54 8.31% 395.27 9% 4% 2.635 0.193 0.00115 CB99028 1.06 8.47% 156.5 23% 16% 3.000 0.230 0.00115 42 43 Horton Infiltration Parameters SWS ID Area (ac) Slope (%) Width (ft) Impervious Area (%) Directly Connected Impervious Area (%) Max.lnf. Rate (in/hr) Min.lnf. Rate (in/hr) Infiltration decay rate (s-1) CB99029 3.71 6.97% 273.07 49% 44% 3.000 0.230 0.00115 CBMH102 5.1 3.74% 184.13 31% 23% 3.000 0.230 0.00115 MH113A 0.91 0.67% 101.05 54% 54% 3.000 0.230 0.00115 MH118A 0.82 2.30% 62.85 48% 48% 3.000 0.230 0.00115 MH123 1.01 4.00% 133.69 52% 50% 3.000 0.230 0.00115 MH128 2.59 4.42% 184.36 22% 21% 3.000 0.230 0.00115 MH136 1.14 1.36% 126.15 49% 49% 3.000 0.230 0.00115 MH141 1.27 2.23% 112.78 55% 55% 3.000 0.230 0.00115 MH147 0.75 3.73% 118.13 61% 61% 3.000 0.230 0.00115 MH153 0.73 1.66% 116.44 63% 63% 3.000 0.230 0.00115 MH1540 2.03 1.46% 90.16 19% 15% 3.000 0.230 0.00115 SD130A 10.51 2.65% 351.38 0% 0% 2.794 0.203 0.00115 SD132 9.04 2.31% 385.27 11% 11% 3.000 0.230 0.00115 SD144A 1.08 0.96% 254.06 44% 44% 3.000 0.230 0.00115 SD149 4.58 1.73% 258.2 15% 13% 3.000 0.230 0.00115 SD1552 0.13 3.50% 66.82 0% 0% 2.845 0.210 0.00115 43