Presented by: Patricia Gertenbach, P.G. E Sciences Ryan Mitchell, P.E. E Sciences Danielle Straub, P.E. City of Melbourne Florida Stormwater Association 2015 Annual Conference June 17 19, 2015
Presentation will be three parts: 1. Introduction to Topic and Why it s Important Pattie 2. Example of Stormwater Facilities that are NOT Ponds Ryan 3. More Example Projects and Lessons Learned - Dani Welcome
Ponds Ponds are a vital tool in managing stormwater storage and treatment Ponds have traditionally been the focus of the Stormwater Management
Ponds Require Land Land can be expensive Many areas of Florida are already built out and land available for ponds is scarce. Marco Island, FL Miami, FL Where will you store and treat the water?
Stormwater Dynamics are Changing As you have heard and will hear from several presenters at this conference, parts of Florida are experiencing flooding as a result of higher tides. We have noticed mangroves growing at outfalls that never had them before. In addition to sea level rise, stormwater managers may have to address more frequent severe storms, such as happened just a few weeks ago in the Midwest: May is already the wettest on record for several cities in the southern Plains states. So far this year, Oklahoma City has recorded 27.37 inches of rain. Last year the state's capital got only 4.29 inches.
Stormwater Dynamics are Changing The storage capacity in some areas is shrinking due to higher groundwater table levels. E Sciences was contracted by the City of Miami Beach to develop a plan to evaluate the correlation between the City s groundwater table elevation and sea level. To save money, we used existing wells, not as evenly distributed or as representative of different scenarios, but provided sufficient information.
Result: Higher Groundwater Table Very good correlation. City revised their Stormwater Master Plan to design to higher groundwater table elevation. Future Studies: You need at least one year of data You can start with existing wells, but be sure to identify the data gaps, in case you want to expand the study.
Where Will You Put the Water? There is speculation that maybe the 100-year storm is becoming the 25-year storm. That systems designed 30 or even 20 years ago, using gravity flow to surface or marine waters may not drain. Adaptation Plans may need to be tied to surface water and ground water levels, rather than years in operation. Flooded street in older neighborhood. Residents report that flooding here now occurs several times per year, whereas in the past, this street rarely flooded.
Where Will You Put the Water? New designs and technologies give stormwater managers more options not just ponds. Work with manufacturers - they are staying ahead of the curve and getting better all the time Now Ryan is going to talk about projects he s done using these and other products and ideas.
Highlands Avenue Parking Lot 1.4 Acre Drainage Basin Site Characteristics Gravel parking lot Type A soils Commercial Shopping Area Poor Drainage Minor flooding No water quality treatment
Highlands Avenue Parking Lot Project Goals Alleviate Flooding Provide Water Quality Treatment Improve Aesthetics
Highlands Avenue Parking Lot Project Design Install inlets in east alley Convert parking lot into a retention basin using PaveDrain pavers Construction emergency outfall to existing storm inlets
Project Design Installed inlets in alleyway 4 feet of aggregate under pavers Exfiltration pipe runs through aggregate Added ADA sidewalk, existing sidewalk was not on City property or ADA. Low maintenance landscape
Construction Sequence
Croton Road Treatment Swale Sheet Flow
Croton Road Treatment Swale
Stormwater Master Plan Completed November 2013 46 Projects 9,735 lb/year of TN estimated 2,716 lb/year of TP estimated Estimated $18,521,570.76 to complete land cost estimated Project Ranking Project Type
Stormwater Master Plan
Stormwater Master Plan
Stormwater Master Plan Great Resource for Staff Teaching Tool for Elected Officials and Upper Management Rate Increase Identify Properties that Need to be Acquired Justifies WQ projects Used as Reference for non-master Plan Projects CIP Budgeting
Lime Street Project Project #1 in Master Plan 56.84 ac Basin North Side Eau Gallie Boulevard, east of Croton Road Dry Retention Pond Estimated 4 ac-ft storage 1 treatment over basin Free Land Estimated Reduction of 738 lb/yr TN and 188 lb/yr TP Grant Funding!!
Lime Street Project GREAT NOT!!! Problems High Groundwater Free flowing artisian well Wetlands PROJECT!! FDOT Pond Not Functioning Correctly Elevation change
Lime Street Project Options 1. Upsize outfall pipe and impact wetlands 2. Connection to FDOT outfall pipe 3. Acquire FDOT pond and combine systems 4. 2 nd Generation Nutrient Removal Baffle Box 64 acre basin 192 lbs/yr TN Reductions 39 lbs/yr TP Reductions
Garfield and Bell Street Baffle Box Master Plan Projects Exfiltration Projects and Dry Retention Cost Prohibitive Unable to buy land New Project Three 2 nd GNSBB One 2 nd GNSBB Ability to monitor two types of baffle boxes Estimated Reduction of 579 lbs/yr TN and 116 lbs/yr TP
Southwest Park Drainage Improvements at Florida Avenue Flooding problem Failing 36 CMP Undersized Pipe 60 Required Adding 2 nd GNSBB NOT IN THE MASTER PLAN Estimated Reduction of 66 lb/yr TN and 9 lb/yr TP
Southwest Park Drainage Improvements at Florida Avenue
Baffle Box Upgrades Paradise Boulevard ±125 ac Melbourne Avenue ± 13 ac Young Street ± 7 ac 1 st Generation Existing Baffle Boxes Estimated Reduction Paradise 186 lbs/yr TN and 29 lbs/yr TP Melbourne Ave - 37 lbs/yr TN and 8 lbs/yr TP Young Street - 8 lbs/yr TN and 1 lbs/yr TP $220/lbs TN $1,342/lbs TP
Street Sweeping and BMP Cleanout Street Sweeping Study City Staff and Contracted Identified HOT Spots O&M BMP Manual Debris Handling Weight vs. Volume Schedule Educated Staff
Lessons Learned Master Plan is a 10,000 foot suggestion "Ground Truthing" needed Don t expect all the projects to work as anticipated Forces Staff to think Water Quality not just maintenance GREAT TOOL!!
Thank you!