The District has adopted a permit program which requires property owners to obtain approval for the following plans:
- Shore impact zone alterations (including ice pressure ridge modification and vegetation removal)
- Rip-rap or beach sand blankets (installation, repair, or replacement)
- Bluff Impact Zone/Steep Slope area within shoreland district alterations
- Retaining walls (installation, repair, or replacement within shore impact or bluff impact zones
- Impervious surface coverage (total cumulative coverage)
~More than 25% of lot coverage
~1 acre (43,560 sq. ft.) or greater
~more than 10,000 sq. ft. in Shoreland District
- Subdivisions, plats, or planned unit developments (PUD’s)
- Highway, road, street, parking lot, or public water access (construction or reconstruction)
- Bridge and/or Culverts, inlets to Waters of the State, stormsewers (new or changes to existing structures)
- Groundwater de-watering – (discharges to Waters of the State)
Permits at PRWD fall in to six general categories, Shoreline Impact Zone Alteration, Impervious Surface, Subdivision/Planned Unit Development (PUD), Bluffs and steep slopes, Roads/Bridge/Culverts, and Groundwater de-watering. The graphic below may help explain project permit requirements.
Permits are issued for projects which meet or exceed certain thresholds. These thresholds are based on the location of the project and the impervious surface coverage (size) of the project. The thresholds target activities that have a potential to could degrade water resource with increased runoff, pollution, and erosion. Follow the guidance below to determine if a permit is required.
Small Site Permit Thresholds:
Any project meeting the criteria listed below will need a Small Site permit:
- Shore Impact Zone Alteration
This includes any alteration to the structures, land, or vegetation within the Shore Impact Zone (one-half the distance of the required building setback from the Ordinary High Water level, i.e. 75 Structure Setback = 37.5 foot Shore Impact Zone)
- Rip-rap: installation, repair, additions, or modification
- Sand Beach Blanket: installation, repair, additions, or modification
- Vegetation Removal
- Land Alteration: including Ice Pressure Ridge repair, grading/filling, or any other activity which disturbs soil and has potential for erosion.
- Impervious Surface: installation, repair, addition, or modification to any impervious surfaces (sidewalks, patio, etc.), small site stormwater management plan may be required
- Bluff and Bluff Impact Zone Alteration
A bluff is defined as a land feature and rises more than 25 feet or more above the Ordinary High Water level and has a average slope of 30% or more. A Bluff Impact Zone extends 20-feet behind the top of the bluff. A permit is required for any activity that disturbs soil or vegetation within the Bluff Area or Bluff Impact Zone
Defined as having an average slope of more that 12% over a distance of 50-feet. Permits are required for any land alteration/disturbance or vegetation removal.
- Impervious Surface Coverage
Impervious Surface coverage exceeding 25% total cumulative lot coverage, new/re-constructed and existing surfaces (see large site permit for more than 10,000 S.F coverage), small site stormwater management plan is required.
Small Site Stormwater Management Plan Requirements
Projects that require a small site stormwater management plan will need to show that stormwater from all impervious surfaces that require treatment are conveyed to an appropriatly sized stormwater Best Management Practice, BMPs (i.e. raingarden, underground infiltration basin, etc). The size of the practice will need to be sized appropriately with the capacity to infiltrate a 1.1" rain event over the impervious surfaces that drain to it.
Large/Commercial Stormwater Management Permit Thresholds:
*Permit required for projects which include construction of new or reconstruction of existing impervious surfaces meeting the total cumulative lot overages below
Note: Impervious surface coverage totals include new (or reconstruction) and existing impervious surface coverage
- Commercial Project exceeding 25% impervious surface lot coverage
- Project exceeding 10,000 S.F. impervious surface coverage within a Shoreland District (1,000 feet from a lake, 300 feet from a river)
- Project exceeding 1 acres impervious surface coverage
- Subdivision, Plats, Planned Unit Developments, Developments based on certified survey
- Changes to, including construction or re-construction of stormwater infrastructure, private or public highways, roads, streets, parking lots, Public Water Access, culverts, and inlets to Waters of the State
- Temporary ground dewatering to Waters of the State
Project that meet or exceed the above threshold will require a stormwater management plan.
Please refer to the below Memo from the District Engineer for design of the Plan
Best Practices for the Design of Stormwater Management Systems