Proposed Water Quality Requirement for Redevelopment

The City of Springfield is soliciting stakeholder comments through 5 p.m. on December 3, 2021 on a proposed water quality requirement for redevelopment sites and other changes to the Flood Control and Water Quality Protection Manual. The City has been working with a Stormwater Technical Committee on changes to the manual that are primarily technical updates and clarifications to stormwater design standards. The proposed water quality requirement for redevelopment sites is the most significant change.

The proposed water quality requirement for redevelopment can be found in Chapter 10.  Below is more information outlining this proposed requirement.

One of the major components of the City’s stormwater requirements for development is the use of stormwater control measures that reduce stormwater pollutants leaving the site to minimize water quality impacts to downstream waterways. Currently, this water quality requirement only applies to new development projects which refers to sites that have not been previously developed. The City is proposing to require water quality measures on redevelopment projects that are demolishing and replacing existing buildings and parking lots.

Under the federal Clean Water Act, the City is required to have a program and ordinance that addresses water quality on both new development and redevelopment projects to comply with its Municipal Separate Storm Sewer System (MS4) permit. This proposed requirement is also consistent with the Springfield-Greene County Integrated Plan which identified urban stormwater runoff as a high priority pollutant source. 

What is the proposed requirement?

It is proposed that redevelopment projects, as defined below, provide water quality measures for the runoff from a 0.5-inch rainfall. This is a reduced requirement compared to new developments which are required to provide water quality measures for the runoff from a 1-inch rainfall.  A reduced requirement is proposed for redevelopment projects because they may have site constraints not found on new development sites and the federal stormwater rules provide flexibility to consider these constraints. This is also consistent with some other communities in Missouri that have reduced requirements for redevelopment. The reduced requirement is only for the impervious area replaced.   Redevelopment projects that result in a net increase in impervious area must meet the full 1-inch rainfall requirement for the net increase compared to existing impervious area.

Learn more about the proposed water quality requirement from Water Quality Compliance Officer Carrie Lamb

How is redevelopment defined and what project size does the proposed requirement apply to?  

Redevelopment means the removal and replacement of existing impervious surface.  It does not include impervious area that is not removed and replaced or activities that do not result in land disturbance, such as building remodeling or overlay of parking lots. The proposed requirement will apply to redevelopment projects that disturb one or more acres of land, which is the same size threshold used for new development projects. It will not apply to removal and replacement of impervious surface that disturbs less than one acre of land. 

Because a reduced requirement is proposed for redevelopment compared to new development, it is necessary to differentiate between the two types of sites.  It is proposed to define redevelopment sites as those that have 40% or greater existing impervious surface within the limits of disturbance (Figure 1, below).  Sites with less than 40% existing impervious surface within the limits of disturbance would be considered a new development project required to meet the 1-inch rainfall requirement (Figure 2, below).  Existing impervious surface means the impervious area existing within the last 12 months from the date of development plan submittal.

FIGURE 1 - Redevelopment site example with 100% existing impervious surface within the limits of disturbance (red line)

Figure 1

Figure 2. New development example with 36% existing impervious within the limits of disturbance (red line)

Figure 2

How will this apply to zoning districts that do not have open space and off-street parking requirements?

The City recognizes that zoning districts that do not have open space and off-street parking requirements have a limited toolbox of stormwater control measures to meet the water quality requirement. For example, a redevelopment in this district may not have open space to construct a detention basin or rain garden, and may not have a surface parking lot to construct pervious pavement. Currently, these zoning districts include Center City and Commercial Street.  Therefore, redevelopment projects located within zoning districts that do not have open space and off-street parking requirements may choose to pay a fee in lieu of meeting the water quality requirement.  However, if the project does voluntarily include off-street surface parking or open space, the water quality requirement must be met on-site to the extent there is space to do so and will only have the option to pay a fee in lieu for the portion that cannot be met on-site.  The fee would be a rate established by ordinance and the funds collected would be used by the City to implement water quality improvements in the James River or Sac River watersheds in which the development is located.  The proposed fee structure is the same fee structure proposed for the recently revised detention fee in lieu because the same types of stormwater control measures can be used to meet both. The fee will be revisited periodically as a normal part of the annual fee study review. The fee in lieu of water quality will be listed separately from the fee in lieu of stormwater detention in the annual fee study and may vary from the detention fee over time based on review. View the proposed fee.