City of Owatonna Stormwater Management

Importance of Adequate Drainage & Lot Grading

A very wet month of June served as a reminder to many residents of Owatonna’s history of flooding and the importance of adequate drainage. Lot grading is an extremely important aspect of conveying from private property to public infrastructure without causing issues on neighboring properties and helps to ensure stormwater management objectives are met. The primary purpose of lot grading is to shape the land to efficiently and effectively direct stormwater away from homes while minimizing impacts to surrounding properties.

Grading plans are blueprints to carry this process out and define how the lot will convey stormwater drainage to designated routes. Based on minimum design standards and best industry practices, they specify design elevations, surface gradients, lot/structure types, swale locations, establishes the grading relationship between adjacent properties. Grading plan review and approval is an effective basis for control of drainage.

Certifying Critical Elevations

To provide a level of protection and assurance to new homeowners and the adjacent landowners, the City of Owatonna requires a Certification of Critical Elevations as part of the permitting process. This ensures the lowest opening to the home has adequate freeboard to any nearby ponding areas, high water levels, emergency overflow routes, and overall lot grading is sufficient when the home is complete. This certification replaces an outdated policy related to foundation height that serves little to no benefit in protecting homes.

After the contractor achieves certification, property owners are then responsible to maintain these drainage patterns and leave intentionally constructed “common property” swales, concentrated drainage routes, and overflow paths unobstructed and free flowing. This includes properly placing fences, utility sheds, and other landscaping items outside of these designated areas. Even simple landscaping projects may have impact to overall drainage.

Residential Infill Development

Residential Infill is the practice of constructing and integrating new buildings into existing neighborhoods. Part of the construction process is re-grading the project area to comply with building codes, drainage laws, and ordinance requirements. Infill developments typically do not have a subdivision lot grading plan, and one must be submitted as part of the building permit application. Many older neighborhoods have little to no mass grading. Final grading of each lot is imperative.

Collaboration with Neighbors

Consulting with adjacent property owners is a critical step when considering any grade changes. In most cases, grading improvements can be made in conjunction with grading for the infill development and avoid future property damage or drainage issues. This may also fix any existing drainage issues, neglected grading, and encourage maintaining common property swales.

Complying with Grading Plan Criteria, It’s Essential

Successful Permit Applications.
Protection from Flooding and Prevents Drainage Issues.
Minimization of Costs.
Harmonious Relations with Neighbors.
Peace of Mind.

Luckily, due to advances in surveying equipment, design software, and automated tools, in conjunction with the required checkpoints, establishing sufficient lot grading, grading plans, and stormwater management has become a far less exhaustive task.

Please visit our construction stormwater website for additional grading permit information: Stormwater Management | Owatonna, MN