Tennessee NPDES Stormwater & Riparian Buffer — Construction & MS4 Permits (TN)
Tracked preemption from the Tennessee overlay bundle.
Overview
← All state preemptionsTennessee overlay roll-upTennessee zoning wikiTennessee building codesFederal overlaysGlossaryFederal-conflict: Yes
Effective
2003-01-01
Sunset
—
Authority
state
Scope
state:TN
Other Tennessee preemptions
Tennessee State Building Code — 2021 I-Codes via State Fire Marshal SBCOTennessee Voluntary Attainable Housing Incentive Programs — IZ Ban Carve-OutTennessee Short Term Rental Unit Act — Statewide STR GrandfatheringTennessee §6-54-127 — Mandatory Inclusionary Zoning & Rent Control BanTennessee Heritage Protection Act — Memorials on Public PropertyTennessee Agricultural District and Farmland Preservation ActTennessee Industrial Development Board TIF — Economic Impact Plan DistrictsTennessee Public Chapter 1101 (1998) — UGB / PGA / RA Growth Plan Regime
Trigger predicate
When this evaluates true for a parcel, the law's preempted fields take precedence over base zoning.
OR
project.disturbed_acresge1project.within_ms4_jurisdiction==Trueparcel.adjacent_to_perennial_or_intermittent_stream==True
Preempted fields
4 fields on the base district schema are rewritten when the trigger fires.
| Field | Op | Value | Note |
|---|---|---|---|
review_type | require | tdec_construction_general_permit_tnr100000 | Construction sites disturbing ≥1 acre (or <1 acre as part of larger common plan) require CGP coverage with SWPPP, BMPs, and termination notice |
site_design.riparian_buffer_min_width_ft | floor_at | 30 | 30-ft natural water-quality riparian buffer required to maximum extent practicable; buffer-averaging allowed with 15-ft absolute minimum at any point |
site_design.riparian_buffer_protection_perpetual | require | True | Permanent protection of buffers required by MS4 permit rule for new and redevelopment projects in stormwater-regulated municipalities |
site_design.post_construction_runoff_volume_control | require | tdec_ms4_runoff_reduction_or_treatment_equivalent | Permanent stormwater management for new development / redevelopment using runoff-reduction practices; alternative treatment train if site constraints prevent on-site reduction |
Citation
Authority source
Tenn. Code Ann. §§69-3-101 et seq. (Water Quality Control Act); TDEC NPDES Construction General Permit TNR100000 (2021); TDEC General NPDES Permit for Discharges from Small MS4s (TNS075000 / TNS076000); Tennessee Qualifying Local Program standards
§ Construction GP §3.5.4 (riparian buffer); MS4 GP Part 4 (permanent SWM)
Research notes
Distinct from TN_69_3_WATER_QUALITY_WETLANDS (ARAP for waters/wetlands alteration) — this overlay covers diffuse stormwater discharges and the construction-stage buffer/SWPPP regime. Phase II MS4s include ~80 TN jurisdictions plus all Phase I (Memphis, Nashville, Knoxville, Chattanooga). Qualifying Local Programs (QLPs) administer construction-stormwater delegation in lieu of TDEC. Federal conflict check: parallel federal CWA §402 NPDES authority (EPA-delegated). Note: TN does NOT have a statewide post-construction runoff volume standard outside MS4 areas — rural counties may have no MS4 trigger at all.