Railroad Lake is a 29-acre productive, nutrient-rich eutrophic lake in Scott County, Iowa. Water quality is graded C based on 2 sampling years through 2024. Overall water quality is improving over recent sampling years. Compared to the 4 other monitored lakes in Scott County, Railroad Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, Iowa DNR, last sampled 2024-09-10. Grade methodology: LakeGrade methodology.
Watch Railroad Lake water quality
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Swimming Safety
Generally safe for swimming, moderate water quality
Water Quality Grade: C, Fair
Murky, only visible to about 5.1 ft. Chlorophyll-a: 8.3 µg/L. Trophic State Index: 53.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 5.1 ft | D |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | 8.3 µg/L | B |
| Trophic State Index (TSI) | 53 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 29 acres |
Where to stay near Railroad Lake
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Fishing Railroad Lake
Water Quality Trend: ↑ Improving
Based on 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.415 m/yr | 4 |
| Chlorophyll-a | ↑ Improving | -51.81 µg/L/yr | 4 |
Location & Depth Map
Free interactive depth-contour map of Railroad Lake, reaching a maximum surveyed depth of 14 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Iowa DNR.
County Ranking
Ranked #2 of 5 lakes in Scott County
Cleaner Lakes Within 30 Miles
Railroad Lake holds Grade C. One nearby lake has a higher grade.
See full comparison →Nearby Lakes in Scott County
Explore Railroad Lake across LakeGrade
More Iowa Lake Rankings
Other Grade C Lakes in Iowa
Eutrophic Lakes in Iowa
More records, surveys & data sources
Reservoir Info (USACE NID)
Railroad Lake is a man-made reservoir impounded by the Railroad Lake Dam (completed 1983), built primarily for recreation on the TR- BLACK HAWK CR.; earth-type dam, 35 ft tall and 525 ft long.
- Surface area
- 29 ac
- Normal storage
- 360 ac-ft
- Max storage
- 750 ac-ft
- Drainage area
- 1.11 sq mi
- Hazard class
- Significant
- Owner
- Scott County Conservation Board
Source: USACE National Inventory of Dams, NID ID IA02208 · Operator website
EPA Impairment Status
Railroad Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit IA 01-NEM-68 · Official waterbody report · Matched by proximity (0.54 km)
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth is a modeled estimate.
Data Sources
Water quality data from the EPA Water Quality Portal
Impairment status from EPA ATTAINS 303(d) database
Lake size & watershed from HydroLAKES (HydroSHEDS)
Grading methodology based on Metropolitan Council standards
Most recent sample: 2024-09-10
Monitoring stations: 1