Fiscal Note
The proposed changes to Chapter 37 are not expected to have a direct fiscal impact on the City. Several of the regulatory changes will result in increased compliance costs for private sector entities associated with new development. The proposed regulatory changes may also result in increased staff time for review and approval of the new requirements, but this staff time would be recovered through charges for review to developers. No appropriation is required.
Title
Repealing and recreating Chapter 37, The Public Stormwater System Including Erosion Control, of the Madison General Ordinances.
Body
DRAFTER’S ANALYSIS: This ordinance makes numerous changes to Chapter 37 of the Madison General Ordinances to update the City’s stormwater code. To simplify the changes, the entire chapter is being repealed and recreated. The notable changes are as follows:
1. Sec. 37.04 amends the definition of redevelopment by increasing the land disturbance threshold from 4,000 square feet to 10,000 square feet, and exempting out parking lot resurfacing. This is meant to address the unintended consequence of encouraging very small parking lots from being improved due to the need to add very expensive stormwater treatment methods. Dane County is moving this to 20,000 square feet for similar reasons.
2. Sec. 37.05(4)(d) is being amended to allow for credits against the stormwater charge, based upon an approved Rate Adjustment and Credit Policy.
3. Section 37.05(6)(b) reorganizes and alters the design standards for privately financed additions to the public stormwater system, including:
a. Making compliance mandatory for new development, and a goal for redevelopment and/or infill development.
b. Culverts across streets at greenway crossings were previously required to be designed for the 25-year event. This revision changes that to the 100-year event.
c. Overflow of the pipe and road system in the event of a 500-year storm event shall not impact any private habitable structures. Site plans will also be reviewed to confirm that the proposed structure elevations are compliant with this design overflow requirement during a 500-year storm event.
4. Section 37.05(7)(a)2.a. reduces the peak volume of discharge subject to the surcharge fee for stormwater system connection permits from 225 gallons per minute to 100 gallons per minute.
5. Section 37.05(7)(b)5. requires that certain sites with private discharges into an enclosed depression be designed to mitigate the increased volume from include existing discharges during the 25 and 100 year storm events.
6. Section 37.05(7)(b)8 updates the remedial procedures available to the City in the event that a private storm sewer or best management practice is not being adequately maintained.
7. Section 37.05(9) updates language about crossings of the public stormwater system, including clarifying the City’s remedial authority where private drainage systems interfere with the public drainage system.
8. Section 37.08(1)(c) is being amended to require that phasing be considered when reviewing erosion control plans.
9. Section 37.08(4) updates erosion control plan performance standards to prevent or reduce certain types of sediment discharge, to ensure that rate or volumetric discharge doesn’t increase during construction, and to create implementation requirements for best management practices.
10. Existing language in Section 37.09 is being updated to make it uniformly refer to stormwater management plans, instead of also calling them reports.
11. Section 37.09(2)(e) is being amended to update requirements of a stormwater management plan’s runoff peak flow calculations, to require specific levels for pre and post development.
12. Section 37.09(2)(l) is being amended to require that buildings in flood prone areas be designed to provide a minimum flood protection to the 100-year event (instead of half a foot above the regional flood elevation).
13. Section 37.09(3) is being amended in several ways to update the stormwater management performance standards in a stormwater management plan. Among the changes include:
a. In Subd. (b), clarifying when oil and grease controls are necessary;
b. In Subd. (c)1., updating the general runoff rate control requirements by requiring sites already subject to an approved plan at the plat or CSM level to meet new development standards to maintain predevelopment peak runoff rates for the 100-year and 200-year events;
c. In Subd. (c)2., requiring new development to meet the following requirements: maintain predevelopment peak runoff rates for 1, 2, 5, 10, 100 and 200-year events, and to safely pass the 500-year event; factor in downstream system capacity to determine the safe capacity of the off-site drainage system; assure that the 100 year event flows through public right-of-ways and that if private property is to be flooded during a 500-year event, entrance elevations must be set to avoid flooding in this scenario; and requiring the use of green infrastructure to capture the first ½ inch of rainfall to meet the rate and volume reductions;
d. In Subd. (c)3., if redevelopment has proposed impervious cover that exceeds 80% of the existing impervious cover, the site is required to reduce peak runoff rates by 15% and reduce runoff volumes by 5% during a 10-year event by using green infrastructure to remove the first ½ inch of rainfall;
e. In Subd. (c)4., development or redevelopment in flood prone watersheds must comply with the detention and storage requirement identified in individual watershed plans, if on file.
f. In Subd. (c)5., if off-site discharge to private lands is to an enclosed depression, the applicant is require to mitigate the increased volume of discharge to include the 25 and 100-year storm events.
14. Section 37.11(1) is being amended to have the Board of Public Works set the erosion control permit fee and stormwater management permit fee. This change is consistent with other permits and fees and will allow easier adjustment of the fee to better recover the City’s costs incurred to administer the permit.
15. Section 37.11(2) allows a contractor who is responsible for completion of erosion control measures to take out a permit.
***********************************************************************************
The Common Council of the City of Madison do hereby ordain as follows:
See "Body" in Attachments.