City of Decatur


City of Decatur
December 2007
Storm Water runoff
What is a watershed?
A watershed is all the land area that drains to a given body
of water. Every stream, river and lake has a watershed.
Bisected by the sub-continental drainage divide,
the north drains to the Gulf of Mexico and the
south drains to the Atlantic Ocean
Watersheds and Streams in Decatur
Required by Law
ƒ Before 1977 necessary to qualify for the Flood
insurance program
ƒ Currently required by the EPD
Water Quality
ƒ Two 303(d) listed streams
ƒ Protecting all of our natural water bodies
‣ Development
ƒ Increased rates of runoff that need to be controlled
ƒ Major areas of concern such as those in the Peavine
ƒ Localized areas of concern
National Pollution Discharge and Elimination
System (NPDES) Storm Water Regulations
a Phase I Municipal Separate Storm Sewer
System (MS4) Permit since June 1994
ƒ Requires a Storm Water Management Plan to reduce the
level of pollutants in the City’s storm sewers
ƒ City of Decatur is a Co-applicant to DeKalb County, An
Intergovernmental Agreement (IGA)
Metropolitan North Georgia Water Planning
District (MNGWPD)
Subdivision/Open Space Development
ƒPost-Development Storm Water
Management for New Development
and Redevelopment
ƒIllicit Discharge and Illegal
ƒFloodplain Management
ƒStream Buffer Protection
ƒLitter Control
Chapter 90 Article VI
Sections 500-505
ƒ Provides conservation for
subdivisions in residential
ƒ Minimum open space must be
at least 40% of the gross tract
ƒ At least 75% of the open
space must be in a
contiguous tract
Waddell Park
Chapter 42 Article V Sections 111-121
Controls and minimizes increases in storm
water runoff, soil erosion and sedimentation,
stream channel erosion, and nonpoint source
ƒ Individual single family developments that do not
increase the unmitigated storm water discharge by
more than 0.50 cfs for the 10-year storm event that
are not part of a common or joint development
Requirements for Site Development Review
ƒ Storm Water Management Plan to show in detail
how post-development runoff will be controlled
ƒ Hydrology Study
ƒ Water Quality calculations, if applicable
ƒ Erosion and Sedimentation Control Plan
ƒ Operations and Maintenance Plan for all storm
water management facilities
ƒ Storm Water Management Inspection and
Maintenance Agreement
ƒ Ongoing City inspections
Chapter 42 Article IV Sections 151-160
Any direct or indirect non-stormwater discharge to the
local sewer system
Common Sources
Car washing, Yard Waste, Animal Waste
Dry weather screenings of outfalls annually by DeKalb
Must immediately notify EPD of spills or illegal dumping
City conducts annual commercial/industrial business
City provides storm drain stenciling, promotes picking
up after our pets
Chapter 42 Article IX Sections 251-260
ƒ Updated in January 2007
Currently undergoing floodplain mapping revisions
with FEMA
Prohibits any new construction in the floodplain
Permits are necessary for all land disturbing activity
within the floodplain
Variances granted through
Zoning Board of Appeals
Chapter 42 Article XI Sections 400-412
25 foot for State + 50 foot for City = 75 foot buffer
Benefits of Buffers:
Removes pollutants
Reduces erosion and sedimentation
Protection and stabilization of stream banks
Maintains base flow
Riparian wildlife habitat
Tree canopy for shade and habitat
Chapter 82 Article III Sections 50-55
ƒ Prohibits any and all littering
ƒ Litter = any organic or inorganic waste material
‣ Penalties:
ƒ A fine of not less than $200 and not
more than $1200
ƒ Violator must reimburse the City
for the reasonable cost of
removing the litter
ƒ Pick up litter for a distance not to
exceed one mile
ƒ Commercial Businesses – 131 Businesses, 9 City sites
ƒ Structural and Source Control Measures
• Detention Ponds – public and private 270 per year
• Catch Basins – 500 per year
• Inlets – 500-600 per year
• Manholes – 50-100 per year
• Flumes/Ditches – 10 per year
• Headwalls – 20 per year
• Storm Drain Lines – 200 per year
Street Maintenance
ƒ 56 miles of roads with approximately 735 miles swept
per year
Litter Control
ƒ 30 tons of litter was removed last reporting period
ƒ DeKalb County, per our Intergovernmental
Agreement, IGA, handles all our monitoring
• Storm water sampling in streams
• Water Quality trend monitoring in streams
• Fecal Coliform monitoring for our 303(d) listed
• Dry weather illicit discharge Screenings
Illicit Discharge and Detection and Elimination
ƒ Outfall Screenings - Dry weather illicit discharge
screenings at random outfalls (4 per 5,000
people – 16 outfalls each year in Decatur)
• 99 outfalls mapped
• If flow is found in dry weather, investigative
measures are taken to identify the source and
eliminate it
Fecal Coliform Sampling
ƒ EPD 303(d) listed streams for fecal coliform
• Shoal Creek – headwaters to the South River
• Peavine Creek – 3 miles in DeKalb County
ƒ Long-term goal is to reduce the pollutant loadings
in the streams
• Encourage picking up after our pets
• “Drains to Stream” decals
• Enforce Water quality runoff
requirements on developments
Construction Site Management
ƒ Site Plan Reviews
• Minor Developments – Single family developments
where the runoff is not ≥ 0.50 cfs for the 10-year
storm event – NO Detention Required
x Submit a survey based site plan and include:
x Current conditions
x Proposed work
x Current zoning setbacks
x Lot coverage calculations (<40%)
x Stream bank buffer, if applicable
x Flood plain limits and elevation, if applicable
Construction Site Management
ƒ Site Plan Reviews – All Other Developments
• Storm water detention with hydrology study
• Operation and Maintenance Plan for all storm water
management facilities (inlets, detention, catch basins)
• Water Quality for sites with ≥ 5,000 ft2 of impervious
area or ≥ 10,000 ft2 of disturbed area
• Erosion and Sedimentation Plan – Must be approved by
Georgia Soil and Water Conservation Commission if the
site is ≥ 1.0 acre for a single family development or ≥
5,000 ft2 of for all other developments
• Must comply with EPD’s General Permit for
Construction Activities for Sites ≥ 1.0 ac
Goal to control erosion and sedimentation at
construction sites – 3 types
ƒ GAR100001 – Stand alone projects
ƒ GAR100002 – Infrastructure projects (Linear)
ƒ GAR100003 – Common Developments
Construction activities ≥ 1.0 acre
NOI filed 14 days prior to start of construction
Inspections – Once every 7 days and/or after
every 0.5 inches of rain
Sampling – At every outfall and/or upstream and
downstream in a near by receiving water body
NOT filed at final stabilization
Educational Activities
ƒ Decatur 101 – Storm Water issues presented during
2 sessions of the program
ƒ Floodplain management information on the City’s
ƒ Clean Water Act decals on inlets
ƒ Investigate all citizen complaints
ƒ Distribute literature such as “Put the Brakes on
Water Pollution” and “ Menu for a Cleaner and
Healthier Environment” from the Clean Water
Remodeling efforts completed in September
Improvements Needed:
West Trinity Place to Decatur Police Station
Decatur Police Department parking area to Electric Ave
Electric Avenue to Commerce Drive
Commerce Drive to North McDonough Street
North McDonough Street, along Maple Street, to Church
ƒ Church Street to East Trinity Place
ƒ East Trinity Place to East Howard Avenue to Hillyer Place
Starts at Commerce Drive and Pate Street, crosses several private
properties, and daylights next to the rear of the Postal Service
234 West Davis at Kings Highway
Glenlake Park Master Plan Project
Stream Bank Restoration and Water Quality
•Bioretention Areas
•Stream bank
North Parkwood Drive and Westchester Drive
Tree Ordinance
ƒ Promotes tree conservation
ƒ Promotes an increase in tree canopy
ƒ Protects existing trees
Zoning Ordinance
ƒ Limits the amount of impervious service on
residential lots - Maximum lot coverage is 40%

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