BASEMENT FLOODING PUBLIC INFORMATION MEETING ADEL PUBLIC LIBRARY COMMUNITY ROOM CITY OF ADEL SEPTEMBER 30, 2015
WHY ARE WE HERE? June 24-25, 2015: Over 7.5 inches of rain in approximately 3 hours Equivalent to 500 year storm event Widespread basement flooding from multiple sources Image from www.google.com
WHY IS WATER FLOODING MY BASEMENT? Could be a single cause or combination: Water coming up through basement floor drains/toilet Water coming into house through ground level windows or doors Sump pump failed to operate or was hydraulically overwhelmed Water coming in through a foundation wall crack or at the foundation wall and floor joint
SANITARY vs. STORM WHAT IS THE DIFFERENCE? Sanitary Sewer Closed system Receives wastewater directly from homes/businesses Sinks / Dishwashers / Showers / Bathrooms Directs wastewater to the City wastewater treatment facility Storm Sewer Open system Collects stormwater from the ground surface Rain / Snow melt / Excess lawn watering Directs collected water to nearest ditch, creek or river
SANITARY vs. STORM WHAT IS THE DIFFERENCE? Image modified from www.google.com
CITY SANITARY SEWER SYSTEM Approximately 100,000-LF of public sewer (6 to 24 inches) Additional ~100,000-LF of private service (typically 4 to 6 inches)
CITY STORM SEWER SYSTEM Approximately 65,000-LF of public sewer (12 to 48 inches)
WHY IS WATER FLOODING MY BASEMENT? Sanitary Infrastructure Issues: Surcharging in sanitary sewer due to one or more of the following: Excessive inflow and infiltration Roots or blockages in sanitary sewer main Sanitary Property Issues: Improper connections (ie foundation drain into service lateral) Roots or blockages in sanitary service lateral
WHY IS WATER FLOODING MY BASEMENT? Stormwater Infrastructure Issues: Street or property flooding due to one or more of the following: Extreme precipitation event Inadequate number of curb inlets or sewer size Plugged curb inlets Roots or blockages in storm sewer main Stormwater Property Issues: Cracks in foundation wall or foundation wall/floor joint Sump pump failed or hydraulically overwhelmed
SURVEY RESULTS Communitywide survey from July 20th to August 31st. 190 unique responses 69% experienced basement flooding as a result of the June 24-25 th storm event 42% have experienced basement flooding before
SURVEY RESULTS Where did the water come from? 30% - Floor drains 13% - Sump pump issue 12% - Foundation issue 7% - Window well 38% - Other/don t know
SURVEY RESULTS Have you experienced basement flooding prior to the June 24 th and June 25 th storm event? 42% - Yes 58% - No If so, how frequently? 58% - 1 time every 5 years 27% - 1 to 2 times per year 12% - 3 to 5 times per year 3% - Whenever it rains
SURVEY RESULTS Does stormwater typically pond or flow through your property during significant rainfall? Ponding 30% - Yes 70% - No Flow Through 26% - Yes 74% - No Photo from Adel resident.
WHAT HAS BEEN FOUND THUS FAR? Preliminary List of Identified Storm Sewer Needs Brickyard Road Storm Sewer Improvements Cassidy Curve Stormwater Basin Improvements Lynne Drive Storm Sewer Improvements Unsewered Area Storm Sewer Improvements Midtown Greene Storm Sewer Improvements North 15 th Street Storm Sewer Improvements Yet to be Identified
BRICKYARD ROAD STORM SEWER IMPROVEMENTS Significant drainage area through Brickyard Road and Main / Rapids / Grove Street area. Potentially re-route existing drainage to alternative creek basin with additional capacity.
CASSIDY CURVE STORMWATER BASIN Multiple stormwater basin issues. Evaluate basin size and emergency overflow characteristics
LYNNE DRIVE STORM SEWER IMPROVEMENTS Significant flooding of Lynne Drive and South 13 th Street intersection. Potentially reinstate emergency overland flow drainage path Possibly increase storm sewer outlet size
UNSEWERED AREA STORM SEWER IMPROVEMENTS
MIDTOWN GREENE STORM SEWER IMPROVEMENTS New development currently under construction Development includes a new stormwater detention basin. Image from www.solidgroundiowa.com.
NORTH 15 TH STREET STORM SEWER IMPROVEMENTS Significant runoff transporting gravel deposition onto Locust Street -> North 15 th Street -> Grove & Rapids Street Potentially construct new curb inlets and storm sewer at North 15 th and Locust Street intersection.
WHAT ABOUT THE SANITARY SYSTEM? Preliminary List of Identified Sanitary Sewer Needs Potential hydraulic restrictions along: Main / Prairie / Greene Street Area Horse n Buggy / Orchard/ Pleasant / Hyvue Street Area Rehabilitation of selected sanitary sewers Reduction in the level of inflow and infiltration Increase the structural stability of sewers
WHAT IS BEING DONE TO ADDRESS THE ISSUES? Community Basement Flooding Survey COMPLETE Issue Identification Session with Staff COMPLETE Public Information Meeting Tonight Prior Field Investigation Review Ongoing Sanitary & Storm System Review Ongoing Hydraulic Strategy Development Oct. 2015 Immediate Need Project Identification Ongoing Long Term Strategy Development Nov. 2015 PLAN OF ACTION REPORT Dec. 2015
WHEN WILL THE IMPROVEMENTS HAPPEN? PLAN OF ACTION REPORT December 2015 Selection of Desired Projects Spring 2016 Allocation of Funding Spring 2016 Design of Improvements Spring/Summer 2016 CONSTRUCTION STARTS Fall 2016 --> 2017
HOW WILL THE IMPROVEMENTS BE PAID FOR? Projects involving sanitary sewer improvements Paid for through Sanitary Utility Current $34.65 for 5,000 GAL user Projects involving storm sewer or stormwater improvements Paid for through Stormwater Utility Current $3.00 per EDU Funding Sources Clean Water State Revolving Fund USDA Rural Development G.O. Bonds/Revenue Bonds Others
$60.00 $50.00 $40.00 $30.00 $20.00 $10.00 $ HOW DO WE COMPARE CURRENTLY - SANITARY? Monthly Residential Sewer Fees for 5000 gal. Urbandale Windsor Heights Perry Grimes West Des Moines Polk City Johnston Clive Pleasant Hill Des Moines Cumming Adel Altoona Mitchellville Panora De Soto Indianola Carlisle Waukee Urbandale Windsor Heights Perry Grimes West Des Moines Polk City Johnston Clive Pleasant Hill Des Moines Cumming Adel Altoona Mitchellville Panora De Soto Indianola Carlisle Waukee Norwalk Ankeny Bondurant
$12.00 $10.00 $8.00 $6.00 $4.00 $2.00 $ HOW DO WE COMPARE CURRENTLY - STORM? Monthly Residential Stormwater Fees Indianola Adel Perry Pleasant Hill Bondurant Urbandale West Des Moines Waukee Altoona Johnston Windsor Heights Ankeny Grimes Clive Panora Norwalk Des Moines Indianola Adel Perry Pleasant Hill Bondurant Urbandale West Des Moines Waukee Altoona Johnston Windsor Heights Ankeny Grimes Clive Panora Norwalk Des Moines
WHAT TYPE OF RATE IMPACT IS POSSIBLE? Clean Water SRF Project Size A Project Size B Project Size C Project Size D Project Size E Project Size F Total Project Costs $250,000 $500,000 $1,000,000 $2,000,000 $3,000,000 $5,000,000 Financing Terms Interest Rate & Term 2.0% & 20 YR 2.0% & 20 YR 2.0% & 20 YR 2.0% & 20 YR 2.0% & 20 YR 2.0% & 20 YR Financing Terms Origination Fees (0.50%) $1,250 $2,500 $5,000 $10,000 $15,000 $25,000 Total Debt $251,250 $502,500 $1,005,000 $2,010,000 $3,015,000 $5,025,000 Total Annual Debt Service $15,300 $30,700 $61,400 $122,900 $184,300 $307,300 Required Debt Service Reserve (10%) $1,530 $3,070 $6,140 $12,290 $18,430 $30,730 Total Number of Water Users 1,516 1,516 1,516 1,516 1,516 1,516 New Monthly Debt Service per User $0.93 $1.86 $3.71 $7.43 $11.14 $18.58 Example Impact to User Rates Impact to User Rates $20.00 $18.00 $16.00 $14.00 $12.00 $10.00 $8.00 $6.00 $4.00 $2.00 $0.00 $250,000 $500,000 $1,000,000 $2,000,000 $3,000,000 $5,000,000 Example Project Size
HOW CAN YOU HELP? Tell us about the issues affecting your property Fill out a basement flooding survey. Send your outside flooding photos to mbenham@mecresults.com Discuss your situation during breakout session following the meeting. Tell your neighbors to get involved as well. Fill out the survey and send outside photos. https://www.surveymonkey.com/r/adelsurvey
QUESTIONS? Derick Anderson, P.E. E-mail: danderson@mecresults.com Jeff Schug, P.E. E-mail: jschug@mecresults.com Gary Brons, M.B.A. E-mail: gbrons@mecresults.com Curt Kampman, P.E. E-mail: ckampman@mecresults.com McClure Engineering Company 1360 NW 121 st Street, Suite A Clive, IA 50325 Office: 515-964-1229