Transcript Stormwater Overview - Union County, North Carolina

Stormwater Overview
Board of County Commissioners
Planning Conference
March 1, 2007
Stormwater Ordinance
 Required to meet Phase II Regulations
 Proposed to address secondary and cumulative
impacts related to:



12 Mile WWTP expansion to 6 mgd
42-inch water transmission main
74 ByPass, Carolina Connector
 Expected to be required for future projects
Proposed Ordinance
 Section I – Stormwater Design Manual
 Section II – General Drainage
Includes requirements in Land Use Ordinance
 Concentrated flow to adjacent properties
 Permanent drainage easement recordation
 Section III – Riparian Buffers
 Streamside Zone
 Undisturbed land along stream channel
 Exemptions include limited access and utility
crossings, gravity sewer and stormwater bmp’s with
no alternative, fences, dam maintenance, stream
restoration

Proposed Ordinance
 Section III – Riparian Buffers (continued)

Upland Zone
 Vegetative land along Streamside Zone

Allowable uses include exemptions from Streamside
Zone, storage buildings less than 150 sq ft, limited
grading, greenways, recreational equipment
Proposed Ordinance
 Section IV – Stormwater Requirements

Applicability:




Cumulatively disturb > 1 acre
Total impervious surface > 20,000 sq ft
Exceed 6% impervious in protected watersheds
Runoff Control




Downstream hydrologic analysis
High Density (exceeds 24% built-upon) control 1-inch
rain, discharge equals pre-development rate, 85% TSS
removal, post equals pre-development run-off rate for 1,
10, and 25-year storm
Convey upstream drainage assuming build-out
conditions
100-year storm elevations defined
Proposed Ordinance
 Section IV – Stormwater Requirements

Final Plat Requirements
 Streams, ponds, wetlands, buffers, base flood boundary
and elevations
 Permanent drainage easements
 Statement lot contains stormwater management facility
 As-Builts
 Annual Inspection Report
 Performance Security
 Plan Review Fee
Schedule
 May 2007 - Presentation to Planning Board
 June 2007 – Public Hearing and comment
period
 August 2007 – Presentation to Board of
County Commissioners