Otter Creek Lake
Tama County, Iowa60 acresView mapDirections
Iowa DNR publishes the water-quality measurements for Otter Creek Lake. Here is what has been measured.
- Eutrophic
- Impaired · Algal growth
- 47 ft max depth
- Limited data
Otter Creek Lake in Tama County, Iowa has water-quality measurements published by Iowa DNR, shown here as reported. Water clarity: 1.3 ft visibility. Phosphorus: 49 µg/L. Chlorophyll-a (algae): 24 µg/L. Surface area: 60 acres.
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. 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. Methodology: how these readings are compared.
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.
Nutrient and algae readings are 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.
Whether Otter 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 Otter Creek Lake
These are the measurements Iowa DNR publishes for Otter 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 1.3 ft of visibility. Phosphorus 49 µg/L. Chlorophyll-a 24 µg/L. TSI 65.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 1.3ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 49µg/L | Measured, not scored The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. |
| Chlorophyll-a (algae) | 24µg/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 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Otter Creek Lake
Answers come straight from the public measurements and survey records on this page.
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.
Column height runs from this lake’s coldest month (68°F) to its warmest (78°F).
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
Max depth
~47 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
Watershed (drainage) area
2 sq mi
HydroLAKES / HydroSHEDS
Shoreline
1.7 mi
HydroLAKES / HydroSHEDS
Elevation
922 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 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 readings cover 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 Oct 23–25, 4 adults. Change dates on the map below.
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a whole trip? See where to stay at Iowa’s top lakes →
Follow Otter Creek Lake’s readings
Email me when new measurements post for this lake. Updates stay free.
Or email
Fishing Otter Creek Lake
Water quality readings over time
2 seasons of samples on record (2020–2021). Calling a direction takes at least 4 years of the same measurement.
Water clarity
Improving2 years
Chlorophyll-a
Improving-22.6 µg/L/yr2 years
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
Designated uses not supporting: Recreation.
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.
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. Its water-quality measurements are published by Iowa DNR and shown on this page as reported.
What is the water quality of Otter Creek Lake?
- Otter Creek Lake in Tama County, Iowa has water-quality measurements published by Iowa DNR, shown here as reported. 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?
- Nutrient and algae readings are 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
More lakes in Iowa
Other Lakes in Iowa
Eutrophic Lakes in Iowa
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)
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)