2016 Regional Stormwater Summit Detroit Stormwater Rules and Drainage Fee Updates Dan Christian, PE, D.WRE Tetra Tech
INTRODUCTION 10/7/2016 DRAFT - For Discussion Purposes Only 2
Historically No formal storm water management requirements Caused flooding, backups and sewer overflows in receiving waters NOW. 10/7/2016 DRAFT - For Discussion Purposes Only 3
Ordinance Development & Code Update Development of new post-construction storm water management regulations to require a baseline level of storm water management on specified development projects Greening of code to promote and support storm water management controls (i.e. green infrastructure) 10/7/2016 DRAFT - For Discussion Purposes Only 4
Internal Technical Advisory Committee DWSD (Permits, Engineering) BSEED (Plumbing, Environmental) Planning and Development Public Works City Council Legislative Policy Law The Nature Conservancy 10/7/2016 DRAFT - For Discussion Purposes Only 5
Stakeholder Input/Outreach: History Stormwater ordinance development effort Since early 2015. Focus group meetings Web-based listening sessions Facilitated work sessions Education Input about key decision points More than 75 groups have been engaged 10/7/2016 DRAFT - For Discussion Purposes Only 6
STORMWATER ORDINANCE 10/7/2016 DRAFT - For Discussion Purposes Only 7
Basics Applicability Create 10,000 sf of impervious surface No distinction between new and re-development Exemptions Single family residential Agricultural operations Submittals Post Construction Storm Water Management Plan DRAFT - For Discussion Purposes Only 10/7/2016 8
Performance Standards Discharge To Water Resource Protection Infrastructure / Channel Protection Flood Control Combined Sewer System 97% of the Detroit System Separate Sewer System 3% of the Detroit System Retention Peak flow and volume 90% Storm Match natural conditions Simple: Retain 1-inch Disturbed area < 50% of parcel then applies only to disturbed area Disturbed area >= 50% of parcel then applies to entire parcel Retention Peak flow and volume 90% Storm Match natural conditions Simple: Retain 1-inch Detention Peak flow only The peak flow rate of storm water runoff leaving the development site shall not exceed the allowable discharge rates. See Design Manual. Retention Peak flow and volume 2-year 24-hour storm Match natural conditions *No Requirements when direct discharge to Detroit River or downstream of the Rouge River Turning Basin Detention Peak flow only Site Area Site Area < 5 acres manage 10-year storm Site Area > 5 acres manage 100-year storm Release rate of 0.15 cfs/acre *No Requirements when direct discharge to Detroit River or downstream of the Rouge River Turning Basin 10/7/2016 DRAFT - For Discussion Purposes Only 9
Rain Precipitation Frequency Current Atlas 14 Data Updated IDF Curve Updated 90% Non-Exceedance Temporal Distributions Type II MSE 3 Huff Atlas 14 ii = 38.416TT0.208 12.326 + DD 0.841 DRAFT - For Discussion Purposes Only 10/7/2016 10
Alternative Compliance Enable applicants to invest in projects on other sites Options Construct equivalent off-site measures Fee-in-lieu Purchase or utilize credits 10/7/2016 DRAFT - For Discussion Purposes Only 11
Additional Requirements/Conditions Operation and maintenance agreement Recording of easements and other protective covenants Right of entry for inspections Inspection fee Right of appeal Periodic maintenance self-inspections DRAFT - For Discussion Purposes Only 10/7/2016 12
GREENING OF CODE 10/7/2016 DRAFT - For Discussion Purposes Only 13
Original Code Update Priorities 1 st Post-Construction (w/alternate Compliance) 2 nd Parking Design Requirements 3 rd Landscaping 10/7/2016 DRAFT - For Discussion Purposes Only 14
Greening Objectives Incentivize the creation of multi-functioning landscapes Storm Water Management Shading/Reduce urban heat island Break up pavement Screening Recreation Reduce the creation of impervious cover the volume/velocity of storm water runoff created the volume/velocity that must be managed onsite 10/7/2016 DRAFT - For Discussion Purposes Only 15
Interior Parking Lot Landscaping Remove language requiring six (6) inch island curbing; revise to allow inlets at appropriate intervals Remove language requiring raised islands 10/7/2016 DRAFT - For Discussion Purposes Only 16
Parking Lot Drainage Require parking lots with 25 or more parking spaces to drain to interior or perimeter landscaping Source: NYC Department of City Planning 10/7/2016 DRAFT - For Discussion Purposes Only 17
Parking Lot Design Revise code to remove barriers and allow more flexibility regarding permeable parking lot surfaces Refer to design manual for allowable surfaces and minimum design standards 10/7/2016 DRAFT - For Discussion Purposes Only 18
Screening Support multi-use of screening areas Revise parking lot screening requirements to allow for vegetated barrier DRAFT - For Discussion Purposes Only 10/7/2016 19
Shade & Street Trees Revise Code to require that all interior landscaping trees (shade trees) be planted according to standards which will ensure survival and maximum storm water management Revise Code to allow trees in storm water management practices to count toward shade tree requirement DRAFT - For Discussion Purposes Only 10/7/2016 20
Recreational Space Revise language to require groundlevel, non-roofed recreational space to be permeable or landscaped Specify that landscaping which is also designed to manage storm water qualifies as recreational space landscaping Allow rooftop recreational space to count as 1 ½ feet of ground recreational space if vegetated Source: Greenroofs.com DRAFT - For Discussion Purposes Only 10/7/2016 21
Urban Agriculture Update urban agriculture ordinance to specifically protect sewer system Include specific best management practices to reduce pollutant discharges Source: communitygarden.org 10/7/2016 DRAFT - For Discussion Purposes Only 22
WHERE ARE WE NOW? 10/7/2016 DRAFT - For Discussion Purposes Only 23
Where are we now? Guidance manuals being drafted policy and design Working out the alternate compliance details Finalize greening code updates Continued stakeholder involvement activities throughout the fall/winter of 2016 Presentation to City Planning Commission and City Council in Spring 2017 DRAFT - For Discussion Purposes Only 10/7/2016 24
DRAINAGE CHARGE 10/7/2016 DRAFT - For Discussion Purposes Only 25
Fair Share Drainage Charge Since 1975, DWSD has charged customers for drainage. DWSD incurs more than $125 million each year to store, transport and treat billions of gallons of storm water runoff and ice melt that flow into the city s combined sewer system. DWSD invested $1 billion in Combined Sewer Overflow facilities (CSOs). May be required to invest in additional facilities, costing everyone more. 10/7/2016 DRAFT - For Discussion Purposes Only 26
Fair Share Drainage Charge Working with City Assessor data and flyover views, DWSD identified 22,000 parcels that contribute to the city s drainage but are not being billed. Charged $750 per impervious acre or 1.7 cents per impervious square foot per month starting October 2016. No backbilling. Orange and green parcels are not charged for drainage. Parcels less than 0.02 impervious acres (side lots) will not be billed. Billing these parcels could provide up to $10 million revenue and offset costs. If everyone pays their fair share, DWSD can bring down rates and all customers pay less. 10/7/2016 DRAFT - For Discussion Purposes Only 27
One Rate By January 2018, all property owners will be transitioned to a uniform rate based on impervious acreage. Impervious cover is hard surfaces such as rooftops, driveways, parking lots that cause storm water to run off. *Less impervious cover results in a lower charge. October 2016: DWSD launches drainage charge credits to reduce drainage bills and promote storm water management and green infrastructure. 10/7/2016 DRAFT - For Discussion Purposes Only 28
Resolve Billing Inconsistency Non-Residential Customer A Billed for 2.1 Impervious Acres x Class 5 Rate Non-Residential Customer B Billed per 1 plus Meter Size Paying $1,621 a month in Drainage Non-Residential Customer C Billed for 2.1 Impervious Acre x Class 2 Rate Paying $190.56 a month in Drainage Non-Residential Customer D Billed per 5/8 to 1 Meter Size Paying $685 a month in Drainage Paying $20.36 a month in Drainage 10/7/2016 DRAFT - For Discussion Purposes Only 29
Phasing Plan Phase I Billing Data Import Phase II New Parcels City Owned Phase III Industrial Phase IV Commercial Phase V Tax Exempt Phase VI Residential Phase VII Faith-Based Target Dates: July 2016 October 2016 January 2017 April 2017 June 2017 October 2017 January 2018 Parcels will convert to impervious acreage billing based on zoning classification New parcels charged $750/IA or $0.02/ISF per month starting October 2016 By 2018, all customers pay same rate based on impervious acreage IA = Impervious Acres. ISF = Impervious Square Foot 10/7/2016 DRAFT - For Discussion Purposes Only 30
Drainage Charge Credits Launch October 2016 Customers can earn up to 80% bill credit.* Up to 40% for reducing annual volume of flow i.e. how much water you prevent from going into the sewer per year. Up to 40% for controlling peak flow rate i.e. slowing the rate at which water leaves your site and enters the sewer. *Credits apply only to the managed area of a parcel 10/7/2016 DRAFT - For Discussion Purposes Only 31
Eligible Practices and Potential Credits Detention Pond: 0-40% Disconnected downspoutsimperviousness: 0-40% Bioretention: 0-80% Permeable Pavement: 0-80% 10/7/2016 DRAFT - For Discussion Purposes Only 32
Drainage Charge Credit Process 1. Validate Parcel and Billing Data 2. Review program information on website 3. Attend Drainage Charge Credit Workshop (starting October 19, 2016) 4. Complete Application for Implemented Practices and Submit to DWSD 5. Design and Implement New Practices 6. Maintain Practices 10/7/2016 DRAFT - For Discussion Purposes Only 33
PROJECTS 10/7/2016 DRAFT - For Discussion Purposes Only 34
September 29, 2016 10/7/2016 35
Vacant Lot Bioretention Stahelin 10/7/2016 36
Porous HMA Parking Lane Artesian 10/7/2016 37
PaveDrain Keeler 10/7/2016 38
Bioswale Tireman 10/7/2016 39
Bioretention Tireman 10/7/2016 40
QUESTIONS AND DISCUSSIONS Daniel P. Christian, PE, D.WRE Senior Project Manager, Water Resources Dan.Christian@TetraTech.com 517.316.3939 10/7/2016 DRAFT - For Discussion Purposes Only 41