Plan commission forwards CDO amendment tightening impervious-cover rules, affirms gravel counts

The Monroe County Plan Commission voted 6-0 at its May meeting to forward ZOA-25-2 — a text amendment to the County Development Ordinance (CDO) addressing maximum impervious cover — to the County Commissioners with a favorable recommendation after clarifying definitions and exceptions.

Jackie Nestor Jelen, planning staff, explained the amendment revises maximum impervious-cover allowances by zone and lot size, adds clarifying superscripts and points readers to Chapter 8.13 (impervious cover rules and exceptions). Jelen said the proposal aims to reduce runoff and other stormwater impacts while recognizing some existing driveways and other built features.

Erica Pena, Monroe County stormwater program manager, advised commissioners that “gravel acts as an impervious surface, because it does not allow the full infiltration, and it compacts over time,” and later stated, “When we look at impervious cover from a stormwater perspective, gravel counts as impervious.” Staff therefore included gravel in the list of surfaces counted toward impervious cover and kept exceptions for driveways that existed on the county’s March 11, 2024 aerial and driveways with proper installation approvals before Dec. 19, 2024.

Planning staff told the commission the county had received 33 variance filings so far this year, 16 of which included impervious-cover requests, and that the amendment is intended to reduce the need for variances going forward while refining per-zone maximums. Visual examples presented by staff showed properties that would remain under the amended limits and others that would require variances absent exemptions for existing driveways.

Commissioners debated how to define gravel and whether to exclude all driveways. Scott Ferris, members and staff noted enforcement and conversion concerns — one commissioner warned that excluding gravel might prompt property owners to install gravel first and later pave without permits. Several commissioners said they support counting gravel as impervious while revisiting the rule’s practical effects in about a year to see how many variance outcomes are affected. After no public comment, the commission voted to send a favorable recommendation to the County Commissioners.

The amendment as forwarded includes: breaking out maximum impervious cover by lot size; pointing to CDO Chapter 8.13 for listed exceptions (including existing driveways documented in the March 11, 2024 aerial); a clarified impervious-cover definition that explicitly includes driveways, parking areas, decks and similar surfaces (now drafted to include gravel); and a staff recommendation to revisit the rule after implementation and observe variance impacts.