Otter Creek Lake
Tama County, Iowa60 acresView mapDirections
Nutrients and algae run above the regional average.
- Eutrophic
- Impaired · Algal growth
- #1 of 3 in the county
- 47 ft max depth
- Limited data
Otter Creek Lake in Tama County, Iowa has a water quality grade of D (Nutrient-rich). Water clarity: 1.3 ft visibility. Phosphorus: 49 µg/L. Chlorophyll-a (algae): 24 µg/L. Surface area: 60 acres.
- Clarity
- 1.3 ft
- Typical in September
- 68°F
- Max depth
- ~47 ft est.
- Area
- 60 acres
- Type
- Eutrophic
- Phosphorus
- 49 µg/L
- Chlorophyll-a
- 24 µg/L
- Trend
- ↑ Improving
Stays via Stay22
Stays near Otter Creek Lake
Compare lakeside cabins, hotels, and vacation rentals near Otter Creek Lake in Tama 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 Otter Creek Lake are listed below.
Top-rated places to stay near Otter Creek Lake
Prices for Sep 11–13, 4 adults. Change dates on the map below.
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Watch Otter Creek Lake’s letter
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Free interactive depth-contour map of Otter Creek Lake, reaching a maximum surveyed depth of 22 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Iowa DNR.
Otter Creek Lake is a 60-acre productive, nutrient-rich eutrophic lake in Tama County, Iowa with an estimated average depth of about 47 feet. Water quality is graded D based on 1 sampling years through 2021. Overall water quality is improving over recent sampling years. Compared to the 2 other monitored lakes in Tama County, Otter Creek Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, Iowa DNR, last sampled 2021-08-04. Grade methodology: LakeQuality methodology.
Swimming Safety
Grade onlyLimited data
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 D is nutrients and algae, not a swimming clearance. Otter Creek Lake is listed impaired under Clean Water Act §303(d) (IR 5) for algal growth, turbidity. Check local advisories before you swim.
Water Quality Grade: D (Nutrient-rich)
Very murky, less than 1.3 ft of visibility. Phosphorus 49 µg/L. Chlorophyll-a 24 µg/L. TSI 65. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1.3 ft | Not graded |
| Phosphorus | 49 µg/L | Not graded |
| Chlorophyll-a (Algae) | 24 µg/L | Poor |
| Trophic State Index (TSI) | 65 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Water Temperature
Otter Creek Lake typically sits around 68°F at the surface in September. Summer average is about 76°F. Usually warmest in Aug (about 78°F) and coldest in May (about 68°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 63 field readings (2010–2020) via the EPA Water Quality Portal. See the full Otter Creek Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | ~47 ft est. |
| Average Depth | ~14 ft est. |
| Surface Area | 60 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 Otter Creek Lake.
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 Otter Creek Lake
Water Quality Trend: ↑ Improving
Based on 2 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.44 m/yr | 2 |
| Chlorophyll-a | ↑ Improving | -22.6 µg/L/yr | 2 |
Reservoir Info (USACE NID)
Otter Creek Lake is a man-made reservoir impounded by the Otter Creek Lake Dam (completed 1968), built primarily for recreation on the OTTER CREEK; earth-type dam, 45 ft tall and 935 ft long.
- Surface area
- 60 ac
- Normal storage
- 680 ac-ft
- Max storage
- 1,290 ac-ft
- Drainage area
- 1.74 sq mi
- Hazard class
- Significant
- Owner
- Tama County Conservation Board
Source: USACE National Inventory of Dams, NID ID IA01032 · Operator website
EPA Impairment Status
Otter 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
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit IA 02-IOW-720 · Official waterbody report
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Otter Creek Lake under Clean Water Act (NPDES) discharge permits.
- Toledo, City Of WtpToledo · 4.6 mi away · NPDES IA0083526
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.
County Ranking
Ranked #1 of 3 lakes in Tama County
Nearby Lakes With Higher Grades
Otter Creek Lake holds Grade D. 2 nearby lakes hold higher nutrient-and-algae grades — useful for a swim day, not a reason to skip lodging here.
Nearby Lakes in Tama County
Frequently asked questions about Otter Creek Lake
Where is Otter Creek Lake?
- Otter Creek Lake is a lake in Tama County, Iowa. LakeQuality grades it D for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Otter Creek Lake?
- Otter Creek Lake in Tama County, Iowa has a water quality grade of D (Nutrient-rich). Water clarity: 1.3 ft visibility. Phosphorus: 49 µg/L. Chlorophyll-a (algae): 24 µg/L. Surface area: 60 acres.
Is Otter Creek Lake safe to swim in?
- The D is nutrients and algae, not a swimming clearance. Otter Creek Lake is listed impaired under Clean Water Act §303(d) (IR 5) for algal growth, turbidity. Check local advisories before you swim.
What is the water temperature of Otter Creek Lake?
- Otter Creek Lake typically sits around 68°F at the surface in September, from 63 EPA Water Quality Portal field readings (2010–2020). That is a typical value for the month, not a live reading.
How deep is Otter Creek Lake?
- No published bathymetric survey covers Otter Creek Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 47 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 60 acres.
Explore Otter Creek Lake across LakeQuality
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Other Grade D Lakes in Iowa
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Where this data comes from
17 measurements from 1 monitoring station, 2020–2021. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Iowa DNR Surface Water Monitoring Data
21IOWA_WQX17 samples · 2020–2021
Analytical methods
- Unknown
- Phosphorus by Colorimetry
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
- 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
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)