Big Creek Lake
Polk County, Iowa885 acresView mapDirections
Iowa DNR publishes the water-quality measurements for Big Creek Lake. Here is what has been measured.
- Hypereutrophic
- Impaired · Algal growth
- Public access
Big Creek Lake in Polk County, Iowa has water-quality measurements published by Iowa DNR, shown here as reported. Water clarity: 2.6 ft visibility. Phosphorus: 80 µg/L. Chlorophyll-a (algae): 35.7 µg/L. Surface area: 885 acres.
Big Creek Lake is a 885-acre highly nutrient-loaded hypereutrophic lake in Polk County, Iowa. Overall water quality is improving over recent sampling years. Limited fish-species data available. Public access is available. Compared to the 11 other monitored lakes in Polk County, Big Creek Lake ranks #9 for water quality.
Source: EPA Water Quality Portal sampling records, Iowa DNR, last sampled 2024-09-30. Methodology: how these readings are compared.
Big Creek Lake covers about 890 acres in Polk County. Vrbo is where to look for cabins and lake homes around Big Creek Lake, and Booking.com and Expedia search hotels near the lake for your dates.
Swimming conditions
Readings onlyBacteria advisory
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, Big Creek Lake never exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 0% of 23 samples across 4 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 Big Creek 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 Big Creek Lake
These are the measurements Iowa DNR publishes for Big Creek 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 2.6 ft of visibility. Phosphorus 80 µg/L. Chlorophyll-a 35.7 µg/L. TSI 65.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 2.6ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 80µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | 35.7µg/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. | 65 | Hypereutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Very high nutrients, dense algae, poor clarity
Ask about Big Creek Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Big Creek Lake typically sits around 74°F at the surface in September. Summer average is about 77°F. Usually warmest in Jul (about 80°F) and coldest in May (about 63°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (63°F) to its warmest (80°F).
Typical surface water temperature by month, from 40 field readings (2010–2023) via the EPA Water Quality Portal. See the full Big Creek Lake water temperature breakdown →
Lake Details
Surface area
885 acres
Public access
Yes
Listed by Iowa DNR
No bathymetric survey has been published for Big Creek Lake, so its depth is not documented here.
Stays via Stay22
Stays near Big Creek Lake
Compare lakeside cabins, hotels, and vacation rentals near Big Creek Lake in Polk 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 Big Creek Lake are listed below.
Top-rated places to stay near Big Creek Lake
Prices for Oct 23–25, 4 adults. Change dates on the map below.
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Fishing Big Creek Lake
Water Quality Trend: Improving
Based on 5 years of monitoring (2020–2024).
Water clarity
Improving5 years
Phosphorus
Improving-4.7 µg/L/yr4 years
Chlorophyll-a
Improving-3.38 µg/L/yr5 years
Reservoir Info (USACE NID)
Big Creek Lake is a man-made reservoir impounded by the Big Creek Diversion Dam (completed 1970), built primarily for flood risk reduction on the BIG CREEK; gravity-type dam, 80 ft tall and 1,750 ft long.
- Surface area
- 885 ac
- Normal storage
- 7,600 ac-ft
- Max storage
- 27,500 ac-ft
- Drainage area
- 76 sq mi
- Hazard class
- High
- Owner
- USACE - Rock Island District
Source: USACE National Inventory of Dams, NID ID IA00014 · Operator website
EPA Impairment Status
Big Creek Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Designated uses not supporting: Recreation.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit IA 04-UDM-1242 · Official waterbody report
Regulated Pollution Sources Nearby
4 EPA-permitted facilities operate within about 5 miles of Big Creek Lake under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- Polk City, City Of Water Treatment PlantPolk City · 1.7 mi away · NPDES IA0082384Recent violation
- Polk City, City Of StpPolk City · 2.1 mi away · NPDES IA0041939
- Jester Park #3-(New Lodge)Granger · 2.5 mi away · NPDES IA0076872
- Jester Park #2Granger · 2.5 mi away · NPDES IA0071803
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 Polk County
Frequently asked questions about Big Creek Lake
Where is Big Creek Lake?
- Big Creek Lake is a lake in Polk County, Iowa. Its water-quality measurements are published by Iowa DNR and shown on this page as reported.
What is the water quality of Big Creek Lake?
- Big Creek Lake in Polk County, Iowa has water-quality measurements published by Iowa DNR, shown here as reported. Water clarity: 2.6 ft visibility. Phosphorus: 80 µg/L. Chlorophyll-a (algae): 35.7 µg/L. Surface area: 885 acres.
Is Big Creek Lake safe to swim in?
- Based on E. coli testing, Big Creek Lake never exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 0% of 23 samples across 4 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 Big Creek 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 Big Creek Lake?
- Big Creek Lake typically sits around 74°F at the surface in September, from 40 EPA Water Quality Portal field readings (2010–2023). That is a typical value for the month, not a live reading.
Can I fish at Big Creek Lake?
- Public access to Big Creek 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.
Explore Big Creek Lake across LakeQuality
Depth, room, public access, and the state wake-sport rules
Species activity outlook by water temperature and season
Where to stay at Iowa's top lakes, each with its readings
Iowa's cleanest lakes, ranked on agency measurements
More lakes in Iowa
Other Lakes in Iowa
Hypereutrophic Lakes in Iowa
Where this data comes from
187 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_WQX187 samples · 2020–2024
Analytical methods
- Unknown
- LAC 10-115-01-1F (UHL)
- Phosphorus by Colorimetry
- LAC 10-115-01-2B (UHL)
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
- In-Vitro Determination of Chlorophyll
- ISU modification of APHA 2130-B
- 2130 B ~ Nephelometric Method
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)