Environmental Rules in St. Martin Parish, LA (2026)
4 rules for unincorporated St. Martin Parish, Louisiana.
Verified from official government sources
Stormwater Management
Developments in unincorporated St. Martin Parish, Louisiana must be drained to numeric storm standards set in St. Martin Parish Code § 14-102. Subsurface storm sewers are designed for a minimum ten-year storm, channel crossings over 100 square feet for a 25-year storm, and the engineer picks the runoff method by drainage area, with breakpoints at 200 acres and 2,000 acres.
Stormwater and Drainage Design Standards in Unincorporated St. Martin Parish
Some RestrictionsSt. Martin Parish Code § 14-102(b), (c)
(b)Runoff determination methods. For drainage areas less than 200 acres, the design engineer shall use the rational method (Q=ciA) procedure for determining runoff rates. For drainage areas between 200 and 2,000 acres, the design engineer shall use the most recent Soil Conservation Service (SCS) Method, as modified by the state department of transportation and development (DOTD) procedure for d...
Erosion Control
In unincorporated St. Martin Parish, Louisiana, a building permit site larger than one acre needs a stormwater pollution prevention plan (SWPPP) that identifies sediment sources and sets best management practices, under St. Martin Parish Code § 8-52. Smaller sites inside a larger common plan of development count too, and all construction operations must follow the plan as a condition of the permit.
Construction Erosion and Sediment Control in Unincorporated St. Martin Parish
Some RestrictionsSt. Martin Parish Code § 8-52(a)-(c)
(a)A stormwater pollution prevention plan (SWPPP) shall be for each building permit site larger than one acre or which forms a portion of a group of sites greater than one acre.(b)A SWPPP must be prepared if activities disturb one acre or more, including smaller sites in a larger common plan of development.(c)The SWPPP shall be prepared in accordance with good engineering practices and must be ...
Flood Zones
Unincorporated St. Martin Parish, Louisiana prohibits fill, new construction, substantial improvements and other development in the adopted regulatory floodway unless a Louisiana licensed engineer shows no increase in flood levels during the base flood discharge. St. Martin Parish Code § 14-70 sets the rule, and development in a special flood hazard area also needs a floodplain development permit.
Floodplain and Floodway Development Rules in Unincorporated St. Martin Parish
Significant RestrictionsSt. Martin Parish Code § 14-70
Located within areas of special flood hazard established in section 14-7 are areas designated as floodways. Since the floodway is an extremely hazardous area due to the velocity of floodwaters which carry debris, potential projectiles and erosion potential, the following provisions shall apply: (1)Encroachments are prohibited, including fill, new construction, substantial improvements and other...
Flood Elevation Requirements
New residential, nonresidential and manufactured home structures in a special flood hazard area of unincorporated St. Martin Parish, Louisiana must have the lowest floor one foot above the higher of three measurements: the FEMA base flood elevation, the centerline of the nearest street, or the highest recorded or modeled 100-year inundation level. St. Martin Parish Code § 14-66(b) sets the freeboard rule.
Flood Elevation and Freeboard Requirements in Unincorporated St. Martin Parish
Some RestrictionsSt. Martin Parish Code § 14-66(b)
(b)Freeboard requirements: In all areas of special flood hazard the following provisions are required for all new construction and substantial improvements: (1)All new residential, nonresidential and manufactured home structures, and any substantial improvements related to the same shall have the minimum lowest floor elevation be one foot above the higher of the following three measurements:a.B...
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