Don Williams Lake
Boone County, Iowa160 acresView mapDirections
Iowa DNR publishes the water-quality measurements for Don Williams Lake. Here is what has been measured.
- Hypereutrophic
- Impaired · Algal growth
- 40 ft max depth
- Public access
Don Williams Lake in Boone County, Iowa has water-quality measurements published by Iowa DNR, shown here as reported. Water clarity: 1.8 ft visibility. Phosphorus: 75 µg/L. Chlorophyll-a (algae): 45.2 µg/L. Surface area: 160 acres.
Free interactive depth-contour map of Don Williams Lake, reaching a maximum surveyed depth of 36 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Iowa DNR.
Don Williams Lake is a 160-acre highly nutrient-loaded hypereutrophic lake in Boone County, Iowa with an estimated average depth of about 40 feet. Overall water quality is declining over recent sampling years. Limited fish-species data available. Public access is available.
Source: EPA Water Quality Portal sampling records, Iowa DNR, last sampled 2024-09-04. Methodology: how these readings are compared.
Don Williams Lake covers about 160 acres in Boone County. For a place on the water, look through cabin and lake-house rentals near Don Williams Lake on Vrbo. For a hotel or motel room, Booking.com and Expedia both search around the lake.
Swimming conditions
Readings onlyRecreation use not supported
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Based on E. coli testing, Don Williams Lake frequently exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 20% of 10 samples across 3 seasons.
This is a historical summary of past testing, not a current condition — bacteria levels change quickly, especially after rain. Always check Iowa’s current beach and health-department advisories before swimming.
Whether Don Williams Lake is safe to swim in today is a call for the Iowa Department of Natural Resources and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Don Williams Lake
These are the measurements Iowa DNR publishes for Don Williams Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Very murky, less than 1.8 ft of visibility. Phosphorus 75 µg/L. Chlorophyll-a 45.2 µg/L. TSI 68.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 1.8ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 75µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | 45.2µg/L | Poor GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 68 | Hypereutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Very high nutrients, dense algae, poor clarity
Ask about Don Williams Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Don Williams Lake typically sits around 76°F at the surface in August. Summer average is about 74°F. Usually warmest in Aug (about 76°F) and coldest in May (about 62°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (62°F) to its warmest (76°F).
Typical surface water temperature by month, from 29 field readings (2010–2023) via the EPA Water Quality Portal. See the full Don Williams Lake water temperature breakdown →
Lake Details
Max depth
~40 ft est.
Surface area
160 acres
Public access
Yes
Listed by Iowa DNR
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Iowa has not published bathymetry for Don Williams Lake.
Lake Size & Watershed
Watershed (drainage) area
31 sq mi
HydroLAKES / HydroSHEDS
Shoreline
4 mi
HydroLAKES / HydroSHEDS
Elevation
1,060 ft
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.
Stays via Stay22
Stays near Don Williams Lake
Compare lakeside cabins, hotels, and vacation rentals near Don Williams Lake in Boone 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 readings cover nutrients and algae, not lodging. Cabins and rentals around Don Williams Lake are listed below.
Top-rated places to stay near Don Williams Lake
Prices for Oct 30–Nov 1, 4 adults. Change dates on the map below.
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Fishing Don Williams Lake
Water Quality Trend: Worsening
Based on 5 years of monitoring (2020–2024).
Water clarity
Stable5 years
Phosphorus
Worsening+64.05 µg/L/yr4 years
Chlorophyll-a
Worsening+4.72 µg/L/yr5 years
Reservoir Info (USACE NID)
Don Williams Lake is a man-made reservoir impounded by the Don Williams Lake Dam (completed 1965), built primarily for recreation on the BLUFF CREEK; earth-type dam, 58 ft tall and 600 ft long.
- Surface area
- 160 ac
- Normal storage
- 2,764 ac-ft
- Max storage
- 4,680 ac-ft
- Drainage area
- 33 sq mi
- Hazard class
- Significant
- Owner
- Boone County Conservation Board
Source: USACE National Inventory of Dams, NID ID IA00134 · Operator website
EPA Impairment Status
Don Williams Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
Designated uses not supporting: Aquatic life, Recreation.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit IA 04-UDM-1249 · Official waterbody report
Regulated Pollution Sources Nearby
4 EPA-permitted facilities operate within about 5 miles of Don Williams Lake under Clean Water Act (NPDES) discharge permits. 3 facilities have a reported Clean Water Act violation in the past three years.
- Pilot Mound City Of StpPilot Mound · 2.8 mi away · NPDES IA0058530Recent violation
- Northern Natural Gas Co. Ogden StationOgden · 4.7 mi away · NPDES IA0046957Recent violation
- Boone, City Of WtpBoone · 5 mi away · NPDES IA0079421Recent violation
- Ymca Camp Of BooneBoone · 4.4 mi away · NPDES IA0070874
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
Nearby Lakes in Boone County
Frequently asked questions about Don Williams Lake
Where is Don Williams Lake?
- Don Williams Lake is a lake in Boone County, Iowa. Its water-quality measurements are published by Iowa DNR and shown on this page as reported.
What is the water quality of Don Williams Lake?
- Don Williams Lake in Boone County, Iowa has water-quality measurements published by Iowa DNR, shown here as reported. Water clarity: 1.8 ft visibility. Phosphorus: 75 µg/L. Chlorophyll-a (algae): 45.2 µg/L. Surface area: 160 acres.
Is Don Williams Lake safe to swim in?
- Based on E. coli testing, Don Williams Lake frequently exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 20% of 10 samples across 3 seasons. That is a historical summary of past bacteria testing, not a current reading and not a swimming clearance. Bacteria levels can spike quickly after heavy rain, so whether Don Williams Lake is safe to swim in today is a call for Iowa's water agency and the county health department; check their current beach advisories before you swim.
What is the water temperature of Don Williams Lake?
- Don Williams Lake typically sits around 76°F at the surface in August, from 29 EPA Water Quality Portal field readings (2010–2023). That is a typical value for the month, not a live reading.
How deep is Don Williams Lake?
- No published bathymetric survey covers Don Williams Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 40 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 160 acres.
Can I fish at Don Williams Lake?
- Public access to Don Williams Lake is listed as yes on the lake record. Seasons, size and bag limits, and whether you need a license are set by Iowa's fish and wildlife agency, so check its current regulations before you go.
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Where this data comes from
63 measurements from 1 monitoring station, 2020–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Iowa DNR Surface Water Monitoring Data
21IOWA_WQX63 samples · 2020–2024
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)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)