(A) Minimum requirements. All development disturbing at least one acre and all redevelopment disturbing at least 10,000 square feet must include provisions to preserve or minimize impacts to pre-development site hydrology and topography, to the maximum extent practicable, through runoff pollution prevention techniques. In addition to runoff pollution prevention measures, storm water treatment BMPs shall be incorporated into plan design as needed to meet the performance criteria in § 53.203.
(B) Runoff pollution prevention.
(1) Storm water management begins with thoughtful design. Site planning that integrates comprehensive storm water management from the outset is the most effective way to reduce and prevent pollution and flooding. Good site planning can also reduce the size and cost of structural solutions. When BMP storm water structures are proposed only at the final stages of design and construction, the result is often unnecessarily large and costly facilities. Planning ahead can prevent the need for large structures.
(2) Site-planning practices. With careful site planning, developers and municipalities can reduce the amount of impervious area created by pavement and roofs, and thus, reduce the volume of runoff and associated pollutants requiring control. Practices that could be considered:
(a) Select site designs that preserve or minimize impacts to pre-development site hydrology and topography.
(b) Protect environmentally sensitive areas.
(c) Practice conservation development.
(d) Use cluster development.
(e) Create open space.
(f) Maximize the flow path from inflow points to outflow points.
(g) Provide underdrain systems, where applicable.
(h) Reduce hydraulic connectivity of impervious surfaces.
(i) Practice rooftop greening.
(j) Relax frontage and setback requirements.
(k) Modify sidewalk standards.
(l) Modify driveway standards.
(m) Use alternative cul-de-sac designs.
(n) Use alternative parking lot surfaces.
(C) Storm water treatment BMPs.
(1) Types of treatment BMPs.
(a) A variety of BMPs are effective in:
1. Filtering storm water;
2. Reducing the speed at which it leaves a site; and
3. Reducing the volume of runoff.
(b) These three actions are critical to reducing non-point-source water pollution and protecting downstream water bodies.
(c) Some types of storm water treatment BMPs are:
1. Retention systems;
2. Detention systems;
3. Infiltration systems;
4. Filtration systems;
5. Constructed wetlands; and
6. Alternative outlet designs.
(2) Location and regional treatment options. All storm water storage facilities shall be constructed within a dedicated storm water storage easement, which meets the minimum requirements set forth in the latest edition of the Lowell Town Standards adopted by the Lowell Common Council.
(3) Location of BMPs. BMPs may be located on site or off site as part of a regional storm water device, practice or system.
(4) Off-site management conditions. The administering authority may approve off-site management measures, provided that all of the following conditions are met:
(a) The administering authority determines that the post-construction runoff is covered by a storm water management system plan that is approved by the local public agency; and
(b) The plan approved contains specific management requirements consistent with the stated purposes and intent of this subchapter.
(5) Off-site facility conditions. The off-site facility shall meet all of the following conditions:
(a) The facility is in place;
(b) The facility is designed and adequately sized to provide a level of storm water control equal to or greater than that which would be afforded by on-site practices meeting the performance standards of this subchapter; and
(c) The facility has a person or entity legally obligated and responsible for its long-term operation and maintenance.
(6) Exemption fee. Where a regional treatment option is utilized, such that the Storm Water Management Board may exempt the applicant from all or part of the minimum on-site storm water management requirements, the applicant shall be required to pay a fee in an amount determined in negotiation with the Board. In determining the fee for post-construction runoff, the Board shall consider an equitable distribution of the cost for land, engineering design, construction and maintenance of the regional treatment option.
(Ord. 2006-25, passed 12-28-06; Am. Ord. 2015-21, passed 9-14-15; Am. Ord. 2019-10, passed 5-28-19)