Post‑Ian Detention: Orange County vs. Miami‑Dade
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Hurricane Ian reminded Florida that stormwater and drainage are not “check‑the‑box” items—they are core to public safety, property value, and permitting success. In the years since, counties across the state have moved to tighten stormwater detention, water‑quality, and resilience requirements, while the statewide stormwater rule has been modernized under the Clean Waterways Act.
Developers often ask: “How do stormwater detention requirements differ between Orange County (Orlando area) and Miami‑Dade County after Ian?” Understanding those differences is essential for site selection, land budgeting, and design. JRH Engineering & Environmental Services is the premier provider of Civil engineering and Structural engineering design Solutions in the states of Texas, North Carolina, and Florida. Our Florida stormwater expertise helps projects in both regions move “Done Quickly. Done Right. And for the Best Value.”
Below we compare key post‑Ian detention and stormwater expectations in Orange County and Miami‑Dade, then explain how JRH optimizes detention so it protects both communities and pro formas.
Post‑Ian Stormwater Context in Florida
Statewide stormwater tightening
Florida’s updated stormwater rule (Clean Waterways Act implementation) increases performance expectations for new systems:
Minimum treatment performance:
At least 80% reduction in average annual total suspended solids (TSS).
Higher treatment expectations for nutrients, with post‑development nitrogen and phosphorus not exceeding pre‑development loads.
Stronger nutrient and net‑improvement standards for projects discharging to Outstanding Florida Waters (OFWs) or impaired waters.
More robust O&M and inspection requirements to ensure long‑term performance of stormwater systems.
These state rules sit on top of local codes in Orange and Miami‑Dade, which have their own detention and site‑specific criteria. JRH’s Florida stormwater practice is built around these performance‑based rules.
Hurricane Ian’s influence
Although Ian’s landfall impacts were strongest on Florida’s Gulf side, the event:
Highlighted vulnerabilities in inland Central Florida flooding, including in Orange County.
Reinforced Southeast Florida’s need for resilient drainage and on‑site retention as sea level, groundwater levels, and rainfall extremes continue to change.
Both counties have moved toward more resilient stormwater practices, but in different ways.
Orange County: Detention, Retention, and LID Emphasis
Code‑based detention and retention requirements
Orange County’s Code of Ordinances requires that stormwater systems provide:
Pollution abatement via retention or detention with filtration of:
The first 0.5 inches of runoff, or
The runoff from the first 1 inch of rainfall, calculated using the site’s runoff coefficient (C).
Recharge in areas with suitable soils (Hydrologic Soil Group “A”), by retaining total runoff from the 25‑year, 24‑hour storm on‑site.
Rate of discharge limitations:
Post‑development peak discharge from the site must not exceed pre‑development peak discharge for the 25‑year storm.
Flood protection:
Sites with no positive outfall must retain total runoff from the 100‑year storm on‑site.
Structures must be flood‑free (residential) or flood‑free/floodproofed (commercial/industrial) per section 30‑279.
These requirements effectively drive robust detention/retention design even before state rule tightening.
Orange County’s LID and resiliency focus
Orange County has also emphasized:
A Stormwater Low Impact Development (LID) Manual, encouraging distributed retention, infiltration, and green infrastructure to reduce runoff volumes and improve water quality.
A Stormwater Resiliency initiative focusing on long‑term resilience projects and policy updates, explicitly referencing hurricane impacts and climate resilience.
MS4 responsibilities under NPDES, emphasizing stormwater pollution prevention and public education.
For developers, this means:
Strong incentives to use bioswales, permeable pavement, rain gardens, and infiltration features to meet both water‑quantity and water‑quality targets.
A need for performance‑based design that documents how LID and detention features satisfy rule performance criteria.
JRH’s work on Florida stormwater navigation and detention land take directly addresses these Orange County constraints.
Miami‑Dade County: Tight Urban On‑Site Retention
Miami‑Dade code and coastal context
Miami‑Dade County, and many of its municipalities, have historically required:
Detention systems designed per the Miami‑Dade County Stormwater Management Manualand local codes, with:
Clear definitions of detention and stormwater treatment via physical, chemical, or biological processes.
Standards for temporary storage and gradual release so as not to exceed design outfall capacity.
Increasing emphasis on on‑site retention of all stormwater for new single‑family homes in shoreline municipalities like Surfside, with requirements that all stormwater be retained on site and that retention walls and systems comply with Miami‑Dade and FBC criteria.
Because Miami‑Dade is low‑lying and heavily urbanized, regional drainage systems have limited capacity and are stressed by high groundwater and sea level. Local codes respond by forcing more stormwater to be:
Held and treated on private sites, not simply discharged to public systems.
Managed through walls, grading, and outfall controls to prevent runoff onto neighboring properties.
Post‑Ian and new statewide rule interaction
Post‑Ian and under the Clean Waterways stormwater rule:
Miami‑Dade projects must also meet higher nutrient reduction and TSS removal standards.
Many coastal and canal‑connected waters are impaired or sensitive, raising performance expectations.
Practically, Miami‑Dade detention/retention design must solve:
Limited percolation due to high groundwater.
Tight urban sites with minimal surface area for ponds.
Stringent on‑site retention requirements imposed by local ordinances and HOAs.
JRH’s Florida work includes underground detention, infiltration trenches, and high‑performance BMPs that maximize land use under these constraints.
Key Differences: Orange vs. Miami‑Dade Detention Post‑Ian
1. Land availability and strategy
Orange County:
More greenfield and suburban development; surface ponds and integrated LID are common.
Code explicitly anchors retention/detention to 25‑ and 100‑year storms, with recharge emphasis where soils allow.
Miami‑Dade:
Dense urban fabric; retrofits and infill dominate.
On‑site retention often must be achieved with underground systems, elevated decks, and sophisticated grading/retention walls.
2. Flood and groundwater context
Orange County must manage intense rainfall and local flooding but has more variation in soil and elevation.
Miami‑Dade must manage high groundwater, tidal backwater, and limited outfall capacity, driving heavier reliance on on‑site storage and water‑tight construction.
3. Policy direction
Both counties now operate under strengthened state stormwater rules; both emphasize performance‑based treatment, nutrient reduction, and net improvement.
Orange County leans heavily on LID and distributed retention as documented in its LID manual and resiliency programs.
Miami‑Dade and its municipalities are increasingly codifying on‑site retention and stormwater wall standards for small lots and coastal settings.
Why Choose JRH for Detention Design in Both Counties
JRH’s Florida stormwater expertise
JRH’s own Florida stormwater guidance highlights:
Comprehensive stormwater services:
SWPPP design plans.
Storm water compliance design.
Retention/detention pond design.
Infiltration trench design.
Jurisdictional wetland and compliance support.
Performance‑based design excellence aligned with new statewide rules.
Focus on optimal system selection based on seasonal high groundwater, infiltration capacity, and pollutant targets.
Our blog on how much land detention will take from Florida sites explains that ponds can consume 5–30% or more of a site—or potentially none at all with strategic design. That is exactly the trade‑off developers face today in Orange and Miami‑Dade.
Integrated civil, structural, and environmental design
From the JRH home page and capabilities:
We provide Civil Engineering, Structural Engineering, Environmental Engineering, and Land Development in Texas, North Carolina, and Florida.
We support grading plan design, site utility design, windstorm engineering, foundation engineering, retention/detention ponds, infiltration trenches, and SWPPP.
For Orange and Miami‑Dade stormwater projects, that means JRH can:
Align pad elevations, building foundations, and pond/wall systems so structures stay dry and accessible.
Design retaining and stormwater walls that meet both structural and hydrologic requirements.
Integrate littoral zone and ecological requirements for wet ponds where needed.
“Done Quickly. Done Right. And for the Best Value.”
Post‑Ian, both counties have increased complexity in stormwater permitting. JRH responds by:
Quickly identifying applicable county, water management district, and state requirements.
Getting it Right with performance‑based calculations and documentation that shorten review cycles.
Delivering Best Value through optimized detention footprints, underground options, and multi‑functional BMPs that protect both compliance and yield.
Common Questions: Orange vs. Miami‑Dade Detention
“Will detention take more land in Orange or in Miami‑Dade?”
In Orange County, surface detention/retention can easily take 5–30% of a site depending on storm standard, soil, and layout.
In Miami‑Dade, land is scarcer, so detention often shifts underground or into structured systems, trading land area for construction cost.
JRH analyzes both land‑take and construction cost to find the right balance for each market.
“Do both counties now follow the new Florida stormwater rule?”
Yes. The statewide rule provides minimum performance standards for pollutant removal, nutrient control, and long‑term maintenance. Counties then add local criteria (like Orange’s code section 30‑277 and Miami‑Dade’s stormwater manual and local ordinances). JRH designs systems to satisfy all three layers: state, district, and county.
“Can JRH handle projects in both regions?”
Absolutely. JRH is active across Florida, with demonstrated stormwater work and regulatory expertise, and is the premier provider of Civil engineering and Structural engineering design Solutions in Texas, North Carolina, and Florida. We routinely adapt our detention strategies to:
Orange County / Central Florida (Orlando region).
Miami‑Dade / South Florida (high‑density coastal sites).
Getting Started with JRH for Florida Detention Design
For your next site in Orange County or Miami‑Dade:
Share your location, size, and program with JRH.
We review applicable county code, water‑management district rules, and statewide stormwater criteria.
We propose concept detention/retention strategies (surface ponds, underground systems, LID, or combos).
We develop permit‑ready designs and calculations that meet or exceed performance standards.
JRH Engineering & Environmental Services is the premier provider of Civil engineering and Structural engineering design Solutions in the states of Texas, North Carolina, and Florida. For post‑Ian detention design in Orange County and Miami‑Dade, we help you navigate complexity and deliver projects that are “Done Quickly. Done Right. And for the Best Value.”
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