Home > Analysis: 321 Sydnor St, Houston, TX 77020 05/01/2025

📊 Environmental Assessment Report

This comprehensive report analyzes both flood risk and industrial pollution exposure for this property. The assessment combines multiple data sources including USGS elevation, FEMA flood zones, historical storm modeling, and EPA Toxic Release Inventory records.

🌊 Part 1: Flood Risk Analysis

Property Overview

This section shows the fundamental characteristics of the property, including its elevation above sea level, FEMA flood zone designation, and our calculated overall flood risk rating based on historical data and topographic analysis.

Address

321 SYDNOR ST HOUSTON 77020

Building Size

1,944 sqft

Total structure area from HCAD building records.

Elevation

36.16 ft

Height above sea level from USGS data.

FEMA Flood Zone

Moderate to Low Risk - Outside 500-year floodplain

Overall Risk

Very Low

Risk based on FEMA zone and simulation.

Risk Assessment Outputs

These detailed metrics show the technical outputs from our flood risk model. They include predicted water depths at the property during a 5000-year flood event and estimated flood damage based on USACE methodology.

Risk Rating

Very Low

Flood Depth

0 ft ±0.5 ft

No flooding at current water level.

Water Surface Elevation (WSE)

N/A

Water surface elevation data not available.

Area Inundated

N/A

Data not available

Nearest Bayou Stage

N/A

No nearby bayou within monitoring range

Depth-Damage Estimate (HCAD Valuation)

Property not flooded at current water level. No damage to calculate.

Depth-Damage Estimate (Neighborhood Comparison)

Property not flooded at current water level. No damage to calculate.

Analysis Method

COG Bathtub Model

Raster-based flood inundation query

Flood Simulation

This simulation shows whether the property would flood based on a 5000-year flood event with 3m (9.84ft) water level. Use the interactive tool to explore different scenarios.

✅ Property Would Be Safe

Safety Margin: 26.16 feet
Severity: Safe

Adjust Flood Simulation

The analysis above uses default settings (5000-year flood, 3m/9.84ft water level). To explore different flood scenarios with interactive maps, return to the main tool:

Open Interactive Analysis Tool

Flood Risk Recommendations

Based on the property's flood risk profile, here are specific action items to consider.

FEMA Zone X (minimal hazard) - flood insurance available at preferred rates.
Review the interactive flood simulator to understand how different rainfall events could affect this property.
Contact Harris County Flood Control District (HCFCD) for drainage projects and flood information.

🏭 Part 2: Industrial Pollution Exposure

Property Pollution Ranking

Moderate

Higher pollution than 72% of Houston homes

This ranking compares pollution levels within 2 miles of this property against 10,000 randomly sampled Houston metro properties. Lower percentiles indicate higher pollution exposure.

Industrial Pollution Nearby (Last 10 Years)

330 thousand lbs

Very High

50.5x more than typical Houston property
≈ 16 dump trucks of chemicals within 2 miles

Total chemical releases from all industrial facilities within a 2-mile radius over the past decade (2014–2024). Data from EPA's Toxic Release Inventory tracking air, water, and land discharges.

💨 Air Pollution (Last 10 Years)

329 thousand lbs

Very High

68.3x more than typical Houston property

Chemicals released into the air from nearby facilities over 10 years. Includes both fugitive emissions (leaks, evaporation) and stack emissions (smokestacks, vents). May affect local air quality.

💧 Water Pollution (Last 10 Years)

54 lbs

Above Typical

Chemical discharges to surface water (bayous, streams, drainage) from industrial facilities within 2 miles over the past decade. May impact local waterways and drainage systems.

❤️ Why It Matters

High chemical activity nearby can indicate industrial zones, truck traffic, or potential odor and noise issues. These factors may affect air quality, long-term property desirability, and neighborhood character. This data helps you understand the industrial footprint around your property.

🏙️ Houston Metro Benchmarks

Comparison with typical Houston properties (based on 10,000 randomly sampled homes). All measurements are for chemicals released within a 2-mile radius.

Period	Total	Air	Water
Typical Houston Property (2014-2024)	6,524 lbs	4,822 lbs	0 lbs
This Property (2014-2024)	329,533 lbs	329,471 lbs	54 lbs
Typical Houston Property (2024 Only)	2 lbs	1 lbs	0 lbs
This Property (2024 Only)	58,823 lbs	35,038 lbs	0 lbs

📊 How This Property Compares to Houston Metro

Based on a random sample of 10,000 Houston properties, this chart shows the distribution of pollution levels across the metro area. The highlighted bar indicates where this property falls compared to other homes. Lower percentiles mean higher pollution exposure.

0-9thMost Polluted

9.9%

10-19th

10.1%

20-29th

9.9%

30-39th

10.1%

40-49th

9.7%

50-59th

10.2%

60-69th

70-79th

5.8%

80-89th

4.3%

90-100thLowest Pollution

34.2%

Higher pollution than 72% of Houston homes

Each bar's width represents the percentage of Houston homes in that pollution range. This property ranks in the 20-29th percentile (top 25% most polluted).

Top chemicals released near this property (past 10 years):

n-Hexane, Styrene, Nitric acid, N-Methyl-2-pyrrolidone, Ammonia

View the full list of 24 chemicals below.

Chemicals Released (2014-2024, 10-Year Total) (24 chemicals)

#	Chemical	CAS#	Air (lbs, 10yr)	Water (lbs, 10yr)	Total (lbs, 10yr)
1	n-Hexane	110-54-3	125,432	0	125,432
2	Styrene	100-42-5	72,717	0	72,717
3	Nitric acid	7697-37-2	35,509	0	35,509
4	N-Methyl-2-pyrrolidone	872-50-4	31,840	0	31,840
5	Ammonia	7664-41-7	25,000	0	25,000
6	Toluene	108-88-3	23,715	0	23,715
7	1,2,4-Trimethylbenzene	95-63-6	8,648	0	8,648
8	Cyclohexane	110-82-7	2,389	0	2,389
9	Xylene (mixed isomers)	1330-20-7	1,434	0	1,434
10	Copper	7440-50-8	1,277	0	1,277
11	Ethylene glycol	107-21-1	856	0	856
12	Zinc compounds	N982	154	0	154
13	Lead compounds	N420	96	54	150
14	Cadmium compounds	N078	106	0	106
15	Chromium compounds (except for chromite ore mined in the Transvaal Region)	N090	84	0	84
16	Cadmium And Cadmium Compounds	N078	70	0	70
17	Cyanide compounds	N106	50	0	50
18	Nitrate compounds (water dissociable; reportable only when in aqueous solution)	N511	25	0	25
19	Nickel	7440-02-0	20	0	20
20	Chromium	7440-47-3	16	0	20
21	Chromium and Chromium Compounds(except for chromite ore mined in the Transvaal Region)	N090	19	0	19
22	Nickel compounds	N495	13	0	13
23	Cobalt	7440-48-4	0	0	4
24	Lead And Lead Compounds	N420	1	0	1

Top chemicals released near this property (2024 only):

n-Hexane, Toluene, Nitric acid, Styrene, Chromium and Chromium Compounds(except for chromite ore mined in the Transvaal Region)

View the full list of 16 chemicals reported within 2 miles for 2024.

Chemicals Released (2024 Only) (16 chemicals)

#	Chemical	CAS#	Air (lbs/yr)	Total (lbs/yr)
1	n-Hexane	110-54-3	12,290	12,290
2	Toluene	108-88-3	11,886	11,886
3	Nitric acid	7697-37-2	755	9,446
4	Styrene	100-42-5	7,400	7,400
5	Chromium and Chromium Compounds(except for chromite ore mined in the Transvaal Region)	N090	6	6,071
6	Nitrate compounds (water dissociable; reportable only when in aqueous solution)	N511	5	3,795
7	Cadmium And Cadmium Compounds	N078	10	1,927
8	Xylene (mixed isomers)	1330-20-7	1,434	1,434
9	Zinc compounds	N982	14	1,335
10	1,2,4-Trimethylbenzene	95-63-6	1,210	1,210
11	Lead And Lead Compounds	N420	0	990
12	Chromium compounds (except for chromite ore mined in the Transvaal Region)	N090	1	902
13	Cyanide compounds	N106	5	46
14	Lead	7439-92-1	0	45
15	Copper	7440-50-8	22	44
16	Lead compounds	N420	0	1