Williamson Pond Max Depth
Lucas County, Iowa25 acresView mapDirections
Nutrients and algae run well above the regional average.
- Hypereutrophic
- Impaired · Turbidity
- #4 of 4 in the county
- 18 ft max depth
Williamson Pond Max Depth in Lucas County, Iowa has a water quality grade of F (Algae-prone). Water clarity: 1.6 ft visibility. Phosphorus: 236 µg/L. Chlorophyll-a (algae): 73.9 µg/L. Surface area: 25 acres.
- Clarity
- 1.6 ft
- Typical in September
- 77°F
- Max depth
- ~18 ft est.
- Area
- 25 acres
- Type
- Hypereutrophic
- Trend
- ↑ Improving
Stays via Stay22
Stays near Williamson Pond Max Depth
Compare lakeside cabins, hotels, and vacation rentals near Williamson Pond Max Depth in Lucas County, Iowa — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water. The water-quality grade measures nutrients and algae, not lodging — cabins and rentals around Williamson Pond Max Depth are listed below.
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Free interactive depth-contour map of Williamson Pond Max Depth, reaching a maximum surveyed depth of 14 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Iowa DNR.
Williamson Pond Max Depth is a 25-acre highly nutrient-loaded hypereutrophic lake in Lucas County, Iowa with an estimated average depth of about 18 feet. Water quality is graded F based on 2 sampling years through 2024. Overall water quality is improving over recent sampling years. Compared to the 3 other monitored lakes in Lucas County, Williamson Pond Max Depth ranks #4 for water quality.
Source: EPA Water Quality Portal sampling records, Iowa DNR, last sampled 2024-10-02. Grade methodology: LakeQuality methodology.
Swimming Safety
Grade onlyAlgae risk
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
The F is nutrients and algae, not a swimming clearance. Williamson Pond Max Depth is listed impaired under Clean Water Act §303(d) (IR 4A) for turbidity. Check local advisories before you swim.
Water Quality Grade: F (Algae-prone)
Very murky, less than 1.6 ft of visibility. Phosphorus 236 µg/L. Chlorophyll-a 73.9 µg/L. TSI 75. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1.6 ft | Not graded |
| Phosphorus | 236 µg/L | Poor |
| Chlorophyll-a (Algae) | 73.9 µg/L | Poor |
| Trophic State Index (TSI) | 75 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Water Temperature
Williamson Pond Max Depth typically sits around 77°F at the surface in September. Summer average is about 78°F. Usually warmest in Jul (about 82°F) and coldest in May (about 71°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 26 field readings (2010–2023) via the EPA Water Quality Portal. See the full Williamson Pond Max Depth water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | ~18 ft est. |
| Average Depth | ~9 ft est. |
| Surface Area | 25 acres |
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Iowa has not published bathymetry for Williamson Pond Max Depth.
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
Fishing Williamson Pond Max Depth
Water Quality Trend: ↑ Improving
Based on 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.088 m/yr | 4 |
| Phosphorus | ↑ Improving | -44.2 µg/L/yr | 4 |
| Chlorophyll-a | ↓ Declining | +10.72 µg/L/yr | 4 |
Reservoir Info (USACE NID)
Williamson Pond Max Depth is a man-made reservoir impounded by the Williamson Pond Dam (completed 1915), built primarily for recreation on the TR-ENGLISH CREEK; earth-type dam, 32 ft tall and 575 ft long.
- Surface area
- 25 ac
- Normal storage
- 223 ac-ft
- Max storage
- 484 ac-ft
- Drainage area
- 2.28 sq mi
- Hazard class
- Low
- Owner
- Iowa Department of Natural Resources
Source: USACE National Inventory of Dams, NID ID IA01296 · Operator website · Matched by proximity (0.06 km)
EPA Impairment Status
Williamson Pond Max Depth 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 04-LDM-1058 · Official waterbody report · Matched by proximity (0.34 km)
County Ranking
Ranked #4 of 4 lakes in Lucas County
Nearby Lakes With Higher Grades
Williamson Pond Max Depth holds Grade F. One nearby lake has a higher nutrient-and-algae grade — useful for a swim day, not a reason to skip lodging here.
See full comparison →Nearby Lakes in Lucas County
Frequently asked questions about Williamson Pond Max Depth
Where is Williamson Pond Max Depth?
- Williamson Pond Max Depth is a lake in Lucas County, Iowa. LakeQuality grades it F for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Williamson Pond Max Depth?
- Williamson Pond Max Depth in Lucas County, Iowa has a water quality grade of F (Algae-prone). Water clarity: 1.6 ft visibility. Phosphorus: 236 µg/L. Chlorophyll-a (algae): 73.9 µg/L. Surface area: 25 acres.
Is Williamson Pond Max Depth safe to swim in?
- The F is nutrients and algae, not a swimming clearance. Williamson Pond Max Depth is listed impaired under Clean Water Act §303(d) (IR 4A) for turbidity. Check local advisories before you swim.
What is the water temperature of Williamson Pond Max Depth?
- Williamson Pond Max Depth typically sits around 77°F at the surface in September, from 26 EPA Water Quality Portal field readings (2010–2023). That is a typical value for the month, not a live reading.
How deep is Williamson Pond Max Depth?
- No published bathymetric survey covers Williamson Pond Max Depth, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 18 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate. The lake covers 25 acres.
Explore Williamson Pond Max Depth across LakeQuality
More Iowa Lake Rankings
Other Grade F Lakes in Iowa
Hypereutrophic Lakes in Iowa
Where this data comes from
53 measurements from 1 monitoring station, 2021–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Iowa DNR Surface Water Monitoring Data
21IOWA_WQX53 samples · 2021–2024
Analytical methods
- Unknown
- Phosphorus by Colorimetry
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
- In-Vitro Determination of Chlorophyll
- ISU modification of APHA 2130-B
Monitoring station identifiers (1)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
Lake size & watershed from HydroLAKES (HydroSHEDS)