Prior-permit stormwater design basis
Carli Professional Office Building
Seminole County, Florida · permit 123954-1 · issued 2010-06-15 · ERP Stormwater Standard General (40C)
Permit action / sequence reviewed
P01123954-1Original authorization · issued 15 Jun 2010 · primary prior-design basis
P01-D02Permit · 15 Jun 2010
Each source is linked here and cited by source/page throughout. Candidate records found by spatial intersection are not treated as applicable until their relationship to the subject system is established.
Engineering summary
The reviewed permit action documents a dry-retention system and a historical stormwater design baseline for discharge to Crystal Lake. It supports reconstruction of the permitted design; it does not establish present-day capacity or current site conditions. Authorization, constructed geometry, common datum, groundwater, and downstream conditions remain to be confirmed.
Key engineering findings
- Permit lineage. P01 is the analyzed 2010 permit action and primary prior-design basis. The district index lists sequence 1 as Compliance P01-D04; current site relationship and authorization remain to be confirmed.
- Existing system. The sources describe a dry-retention pond, control weir, 15-in RCP, right-of-way drainage, and discharge toward Crystal Lake P01-D01, p.2 · P01-D03, p.2.
- Historical model baseline. The 55.57-hour recovery result and the recorded discharge/stage pairs are model-reconstruction benchmarks, not evidence of available capacity P01-D01, p.12.
- Elevation relationships. The recorded 100-year stage is 1.52 ft below the berm, and the pond bottom is 1.00 ft above recorded SHGWT. A common vertical datum was not resolved P01-D01, p.12 · P01-D01, p.35.
Existing system documented in the record
Site drainage → inlets and piping → dry retention pond → control structure → 15-in RCP → right-of-way drainage/swale → Crystal Lake. P01-D01, p.2 · P01-D03, p.2
Prepared from public regulatory records. Calculated differences are arithmetic over cited inputs. This brief is record research, not a survey, regulatory determination, engineering design, or sealed work.
01 · Recorded design criteria
Recorded stormwater design basis
Record values and calculated differences are grouped by engineering function. References correspond to the linked source index on page 1 and the full register on page 4.
Water quality and recovery
| Parameter | Recorded criterion | Recorded result | Calculated difference | Source |
|---|---|---|---|---|
| Water-quality volume | 0.042 ac-ft required | 0.043 ac-ft provided | 0.001 ac-ft | P01-D01, p.5 P01-D01, p.12 |
| Treatment recovery | ≤ 72 hours | 55.57 hours | 16.43 hours below maximum (22.8%) | P01-D01, p.12 |
Engineering interpretation. Provided volume is essentially equal to the recorded requirement at the precision reported; this comparison does not establish available capacity. The recovery result is historical model performance and remains dependent on soils, groundwater, and constructed pond geometry.
Discharge and stage results
| Event | Pre cfs | Post cfs | Modeled reduction | Peak stage | Source |
|---|---|---|---|---|---|
| Mean annual / 24-hour | 0.503 | 0.372 | 0.131 cfs (26.0%) | El. 50.74 ft | P01-D01, p.12 P01-D01, p.12 |
| 25-year / 24-hour | 1.547 | 1.490 | 0.057 cfs (3.7%) | El. 51.10 ft | P01-D01, p.12 P01-D01, p.12 |
| 100-year / 24-hour | 2.132 | 1.994 | 0.138 cfs (6.5%) | El. 51.23 ft | P01-D01, p.12 P01-D01, p.12 |
Engineering interpretation. The 25-year / 24-hour pair has the smallest modeled reduction. All three pairs and peak stages are historical model-reconstruction benchmarks, not current discharge allowances or approval criteria.
Recorded hydraulic assumptions
| Parameter | Record value | Record note | Source |
|---|---|---|---|
| Seasonal high groundwater | Elev. 48.75 ft | Vertical datum not resolved in the reviewed material. | P01-D01, p.35 |
| Tailwater | Elev. 50.00 ft | Right-of-way piping system modeled as flowing full. | P01-D01, p.2 |
| Control crest | Elev. 50.50 ft | Recorded control-structure elevation. | P01-D01, p.11 |
02 · Permitted system
Permitted drainage system and elevation relationships
The drainage path and components below are documented in permit action P01. Current location, condition, and elevations have not been established by this review.
Site runoff→Inlets + piping→Dry retention pond→Control weir→15-in RCP→ROW system + swale→Crystal Lake
System components
| Facility | Record description | Confirmation needed | Source |
|---|---|---|---|
| Drainage inlets and piping | Onsite drainage inlets and underground piping conveying sheet-flow runoff to the retention pond | Confirm location, inverts, and condition. | P01-D01, p.2 |
| Dry retention pond | Dry retention pond, bottom elevation 49.75 ft, bottom area 2,490 sq ft; stores 0.043 ac-ft at weir crest 50.50 and 0.172 ac-ft at elevation 52.75 | Survey bottom, berm, and storage geometry. | P01-D01, p.35 |
| Control structure weir | Rectangular overflow weir in the drainage control structure; 12-inch weir length, crest/control elevation 50.50 ft | Survey crest, opening, and condition. | P01-D01, p.11 |
| Outfall pipe | 15-inch circular (RCP) outfall pipe from the pond control structure, 40 ft long; upstream invert 48.75 ft, downstream invert 48.55 ft | Confirm inverts, connection, and condition. | P01-D01, p.29 |
| Swale | Offsite open swale downstream of the right-of-way piping system, draining to Crystal Lake | Confirm grades, ownership, maintenance, and tailwater response. | P01-D01, p.2 |
Elevation relationships
| Feature | Record elevation | Relationship in the reviewed record | Source |
|---|---|---|---|
| Seasonal high groundwater | 48.75 ft | Groundwater basis used by the record. | P01-D01, p.35 |
| Pond bottom | 49.75 ft | 1.00 ft above recorded SHGWT (calculated). | P01-D01, p.35 |
| Tailwater | 50.00 ft | Downstream model assumption. | P01-D01, p.2 |
| Control crest | 50.50 ft | Recorded control elevation. | P01-D01, p.11 |
| 100-year / 24-hour peak stage | 51.23 ft | Highest modeled stage in the reviewed record. | P01-D01, p.12 |
| Pond berm | 52.75 ft | 1.52 ft above the highest modeled stage (calculated). | P01-D01, p.12 |
Datum note. A common vertical datum was not resolved from the reviewed material. The relationships above are shown as recorded and require reconciliation with current survey before reliance.
03 · Assessment and follow-up
Engineering assessment and required confirmations
Record-supported conclusions
- Permit lineage.P01 is the analyzed prior permit action and primary design-basis source set. The district index lists sequence 1 as Compliance P01-D04; current site relationship, authorization, and O&M responsibility remain to be confirmed.
- Existing system.The cited sources document the drainage path and principal facilities from site collection through Crystal Lake P01-D01, p.2 · P01-D03, p.2. They do not establish present condition or ownership.
- Historical model baseline.Recorded treatment, recovery, discharge, and stage results form a model-reconstruction baseline; they do not establish present performance or available capacity P01-D01, p.12.
- Current conditions.Constructed geometry, common datum, groundwater, and downstream boundary conditions remain unresolved. Recorded elevation relationships require reconciliation with current survey P01-D01, p.35.
Required confirmations
| Open item | Why it matters | Resolution |
|---|---|---|
| Site relationship, authorization, and O&M | The district index lists sequence 1 as Compliance P01-D04; issued 15 Jun 2010 P01-D02, p.1; five-year construction term P01-D02, p.3; two-year inspection interval P01-D02, p.5. Current authorization and O&M responsibility remain unresolved. | Confirm site/permit relationship, current agency file, O&M entity, and modification path. |
| As-built geometry and datum | Storage, freeboard, and control relationships depend on constructed elevations. | Obtain the completion/as-built record and reconcile it to a current datum-tied survey. |
| Soils, SHGWT, and recovery | Recovery performance depends on infiltration and groundwater conditions. | Confirm current geotechnical and groundwater inputs before rerunning recovery. |
| Outfall and tailwater | The record assumes a full right-of-way pipe and Elev. 50.00 ft tailwater. | Inspect the receiving system and establish the current downstream boundary condition. |
| Baseline model reconstruction | The historical results are the only documented quantitative performance baseline. | Reproduce treatment, recovery, discharge pairs, and stages before evaluating changes. |
Full source register
P01123954-1Original authorization · 15 Jun 2010 · primary prior-design basis
- P01-D01Drainage calculations · 17 Mar 2010
- P01-D02Permit · 15 Jun 2010
- P01-D03Technical Staff Report · 9 Jun 2010
- P01-D04SJRWMD permit index · sequence 1 · queried 24 Jul 2026
Basis and limitations. An analyst selected permit action P01 and reviewed the cited sources. Spatially intersecting records were excluded unless their relationship to the subject system was established. Calculated differences are arithmetic over cited inputs. This is not a title opinion, survey, regulatory determination, engineering design, or sealed work; the source file controls.