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CITY OF ANN ARBOR STORMWATER UTILITY BASICS
Jennifer Lawson, CSM, ASLA Water Quality Manager October 2013
How old is that City-owned Pipe?
Decade Constructed Feet of Main Miles of Main Percent of Total 1900s 410 0.08 0.03% 1910s 52,545 9.95 4.29% 1920s 135,768 25.71 11.09% 1930s 40,451 7.66 3.30% 1940s 37,775 7.15 3.09% 1950s 197,359 37.38 16.12% 1960s 303,638 57.51 24.80% 1970s 149,789 28.37 12.24% 1980s 69,027 13.07 5.64% 1990s 114,035 21.60 9.32% 2000s 60,835 11.52 4.97% 2010s 6,689 1.27 0.55% unknown 55,837 10.58 4.56% TOTAL 1,224,158 231.85
Overview
What is a Stormwater Utility? Rate Structure Data Management/Impervious Surface Calculation
What can you do with a utility? Public Education Funded Activities CIP O&M MS4 Compliance
What is a Stormwater Utility?
What is a Stormwater Utility?
A dedicated funding source to support an administrative organization that plans, designs, constructs and maintains a stormwater management system, sediment and flood control programs and projects, and provides stormwater education.
…you have to have an outcome that the community will embrace and support…
Takeaway Message
Stormwater Utility
Formed in early 1980’s; updated 2007 Rates based on Impervious Area Cannot be used for first-time service (i.e., SAD) Revenue only be used for Stormwater Projects and
Programming
Stormwater Utility Does What?
Asset Management Operations Maintenance Scheduling/Work Orders Asset Inventory
Capital Improvements Regulatory Programming
NPDES Permitting NFIP Implementation
Level of Service Principles
Protect public health, safety, and welfare Protect ecological health Conduct comprehensive planning to determine
priorities Encourage shared responsibility Offer incentives to guide desired behaviors Educate stormwater system users Provide an understandable, equitable rate structure
**Developed by Storm Water Citizens Advisory Task Force (2007)
Rate Structure
Residential Rates – 2013
Single-Family and Two-Family Residential
** Plus a $6.77 customer charge per quarter.
Measured impervious area Representative Impervious Area
Quarterly charge
Less than or equal to 2,187 square feet 0.04 acres $14.20
Greater than 2,187 square feet to less than or equal to 4,175 square feet
0.07 acres $24.85
Greater than 4,175 square feet to less than or equal to 7,110 square feet
0.12 acres $42.60
Greater than 7,110 square feet 0.21 acres $74.55
Commercial Rates – 2013
Commercial and other properties (e.g., multi-family, office, institutional, and industrial land uses) are billed directly on the impervious areas at a rate of $355.00 per acre per quarter, plus a $6.77 customer charge per quarter.
Ann Arbor Stormwater Utility Revenue
2007 = $4,041,938.44
2008 = $4,777,706.89
2009 = $5,190,173.61
2010 = $5,298,685.15
2011 = $5,396,396.30
2012 = $6,062,364.00
2013 = $6,059,170.00
Data Management/GIS Classification
Remote Sensing Classification
Use new 6-inch resolution orthoimagery to yield 2-foot resolution imperviousness map grid All pavement and travel ways All buildings, including decks and roof
overhangs Use Ann Arbor GIS data as
classification Benchmark Data Quality Assurance
Manual digitization Field verification
Adjustments & Provisions
Recognize ratepayer actions/situations Possible Adjustments:
Map interpretations (sandbox example) Non-contributing areas Direct flow to Huron River Flow outside City limits Runoff does not enter the City Stormwater system
Retention of ALL stormwater Runoff does not enter the City Stormwater system Back-to-back 100-year storm events
Data Imagery Management
Systems Planning Unit updates every three years Share costs with other City units New orthoimagery acquired in the spring of 2012. New impervious surface layer generated by
consultant. QA/QC by City Staff *time. Implemented updated impervious surface layer in
Fall 2013.
Funded Initiatives
Capital Projects
Mary Beth Doyle Park Wetland Preserve Easy Street – Permeable Pavers Stormwater GIS and SWMM Model Stadium Blvd. Stormwater Quality Units Pioneer HS Underground Detention West Park Stormwater Management Sylvan Ave. – Permeable Asphalt Malletts Creek Bank Stabilization Impervious Area Disconnection/Infiltration Burns Park – Permeable Concrete Alley
Regulatory Compliance
NPDES MS4 Permit Public Education Illicit Discharge Elimination Program Post Construction Stormwater Controls Construction Stormwater Controls (Part 91, etc.) Pollution Prevention/Good Housekeeping
TMDLs E.coli Phosphorus TSS/Biota
Stormwater Education
Public and Political support for stormwater projects and policy improvements
Phosphorous Ordinance
NPDES Education Compliance Single Family Stormwater Management Ordinance Adopt - A - Drain Program
Revised Landscape Ordinance
…you have to have an outcome that the community will embrace and support…
Takeaway Message
