5.1 Regulatory Program
As discussed in Section 3.6 above, future development is not expected to contribute significant additional stormwater volume or phosphorus loads to Minnehaha Creek. However, an overall reduction in phosphorus loading from the subwatershed is desirable and additional reductions from regulation of pollutant loading and volume should be considered. Additional infiltration and minimization of new impervious surface should be encouraged to reduce pollutant loading from runoff, help restore base flow in the creek and reduce peak runoff rates. To decrease pollutant loading, control new volumes, encourage increased infiltration and provide for additional wetland management, additional regulation may be necessary. A decision on rulemaking needs/standards can only be made after the formal rulemaking process. In addition, further amendments to the Rules should not be precluded by the content of the plan.
Additional regulatory controls on permitted development and redevelopment will be considered for this subwatershed to increase phosphorus load reduction requirements, add volume management and infiltration requirements, implement wetland management in accordance with management classification, and increase scrutiny of development that may impact groundwater or key conservation resources. Regulations providing an incentive such as a volume reduction credit to developers to maintain undisturbed areas, reforest, or plant native vegetation may be considered.
The following are revised or additional regulatory controls in this subwatershed that would be necessary to assist the District in meeting the goals of this Plan:
- Amend existing or establish new District rules requiring abstraction of the first one inch of rainfall on new permitted development and redevelopment.
- Amend existing or establish new District rules requiring greater than 50 percent phosphorus removal on new permitted developments within the subwatershed
- Amend District rules to incorporate a requirement for stormwater management plan approval prior to submittal of a preliminary plat.
- Amend existing or establish new District rules requiring submittal of a functions and values assessment for all proposed wetland impacts requiring a permit; mitigation of all fill in Preserve category wetlands; and specifying by management classification stormwater discharge pretreatment, buffer, hydroperiod, and other wetland standards.
- Establish new District rule requiring an additional level of analysis and review of permitted development and redevelopment where there is a potential to adversely impact groundwater connected to a surface water feature.
- Require pretreatment of stormwater discharged to wetlands or infiltration areas in the areas of high aquifer sensitivity.