Stormwater Management

Question 1

Minimum requirements for managing stormwater?

Answer 1

-Existing drainage ways shall not be filled, altered, or impeded so that water will cause erosion, drainage concerns, or flooding
-Prior to approval the developer shall make provision for continued maintenance of the erosion and sediment control system
-Stormwater management standards and construction activities are undertaken to control and manage runoff from site
-Stormwater management plan in place that addresses the long-term management
-Stormwater management site plan should include site information as required for a development certificate
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Question 2

Design standards for drainageways include?

Answer 2

• no fences or structures constructed across drainageway that will reduce/restrict flow
• banks of drainageway shall not exceed 5 feet horizontal to 1 foot vertical in gradient
• bed of drainageway shall be protected with turf, sod, or perennial vegetation. Rip rap may be used if other options will not function properly

Question 3

Design standards for water velocity?

Answer 3

• flow controlled to a velocity that will minimize erosion of waterway
• flow controlled through installation of diversions, berms, slope drains, and other similarly effective structures
• stormwater velocity to a drainageway must be minimized through an energy dissipation accepted method

Question 4

Design standards for sediment control?

Answer 4

• pervious and impervious sediment traps and other sediment control structures shall be incorporated throughout watershed to prevent sedimentation of drainageways
• temporary pervious sediment traps could consist of a construction of bales of hay with a low spillway embankment section of sand and gravel that permits a slow movement of water while filtering sediment
• permanent impervious sediment control structures consist of sediment basins and shall be utilized to remove sediment from runoff prior to its disposal in any permanent body of water
• sediment control devices must be removed upon stabilization of soils at site

Question 5

Design standards for maintenance of erosion control system?

Answer 5

• erosion and velocity control structures shall be maintained in a condition that will insure continuous functioning
• sediment basins shall be maintained as the need occurs to insure continuous desilting action by the property owner
• areas utilized for runoff waterways and sediment basins shall not be allowed to exist in an unsightly condition. banks of sediment basins and waterways shall be landscaped

Question 6

Purpose and intent of SSTS?

Answer 6

• establish minimum requirements for regulation of ISTS and MSTS for the treatment and dispersal of sewage to protect public health and safety, groundwater quality, and prevent or eliminate the development of public nuisances
• promote the protection of lakes, rivers and streams, wetlands, and groundwater in Winona County essential to the promotion of public health, safety, welfare, socioeconomic growth and development of County
• regulation of proper SSTS construction, reconstruction, repair and maintenance to prevent the entry and migration of contaminants, thereby protecting the degradation of surface water and groundwater quality
• establishment of minimum standards for SSTS to prevent contamination and identify and control of consequences if contamination happens
• appropriate utilization of privy vaults and other non-water carried sewage collection and storage facilities
• provision of technical assistance and education, plan review, inspections, SSTS surveys and complaint investigations to prevent and control water-borne diseases, lake degradation, groundwater related hazards, and public nuisance conditions

Question 7

Purpose of Management Plans for SSTS?

Answer 7

To describe how a particular SSTS is intended to be operated and maintained to sustain the performance required.

Question 8

Required contents of a Management Plan?

Answer 8

• operating requirements describing tasks that the owner can perform and tasks that a service licensed service provider must perform
• monitoring requirements
• maintenance requirements including procedures and a schedule for routine maintenance
• statement that the owner is required to notify the Department when the management plan requirements are not being met
• disclosure of the location and condition of the additional soil treatment and dispersal area on the owner’s property
• other requirements as determined by Department