Stormwater Detention Policy

Proposed developments must provide stormwater detention to temporarily store runoff.

The Stormwater Detention Policy applies to all new developments with the exception of:

• Downtown St. John's (subject to City infrastructure having sufficient capacity)
• Infill development (exempted provided that the developer can demonstrate that there will be no downstream issues associated with capacity, flooding, erosion control, and velocities)
• Cemeteries, grassed playing fields and vegetated areas of public sports and recreational facilities

Plans

Every developer has to have a stormwater management plan which meets the requirements of this policy. The City reserves the right to accept or reject the stormwater management plan or propose amendments. The City can offer guidance as to the type of stormwater detention which might be acceptable for a particular development if requested.

The City's Development Design Manual provides the design methodology that the developer must use to design and construct the stormwater detention system.

Costs

Developers must pay all costs of stormwater infrastructure constructed within the borders of their property. In the case of a regional stormwater detention system, where the detention infrastructure serves more than one development, the regional detention infrastructure costs will be shared amongst developers in proportion to the amount of stormwater volume each development is expected to detain. Where the City must upgrade its infrastructure outside the borders of the development, the City may recover its costs, including interest and financial charges, through assessment charges or fees.

Ownership  

The City may take ownership and maintenance of stormwater detention systems in residential developments. Detention systems in commercial, industrial, or institutional developments remain the responsibility of the developer or property owner.

When the City takes ownership of a system, it must meet the following requirements:

• The developer must construct a stormwater detention system in accordance with the approved engineering plans and must convey the system, and associated lands, at no cost to the City as a condition of final approval.
• The system must be 100% complete (in accordance with the approved plans), operational, and commissioned in the presence of City staff. The developer must continue to own and maintain the detention system until accepted by the City.
• The City, at its discretion, may require a field test to demonstrate the maximum discharge rate from the detention facility for a designated water level/head.