Slipbluff Lake
Decatur County, Iowa18 acresView mapDirections
Iowa DNR publishes the water-quality measurements for Slipbluff Lake. Here is what has been measured.
- Mesotrophic
Slipbluff Lake in Decatur County, Iowa has water-quality measurements published by Iowa DNR, shown here as reported. Water clarity: 9 ft visibility. Phosphorus: 17.5 µg/L. Chlorophyll-a (algae): 4.5 µg/L. Surface area: 18 acres.
Free interactive depth-contour map of Slipbluff Lake, reaching a maximum surveyed depth of 21 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Iowa DNR.
Slipbluff Lake is a 18-acre mesotrophic lake in Decatur County, Iowa. Overall water quality is declining over recent sampling years. Compared to the 2 other monitored lakes in Decatur County, Slipbluff Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, Iowa DNR, last sampled 2024-09-15. Methodology: how these readings are compared.
Swimming conditions
Readings onlyLow algae
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. Check local advisories before you swim.
Whether Slipbluff 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 Slipbluff Lake
These are the measurements Iowa DNR publishes for Slipbluff Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Moderate clarity, visible to about 9 ft. Phosphorus 17.5 µg/L. Chlorophyll-a 4.5 µg/L. TSI 45.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 9ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 17.5µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | 4.5µg/L | Good GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 45 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Slipbluff Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Slipbluff Lake typically sits around 78°F at the surface in September. Summer average is about 79°F. Usually warmest in Jul (about 83°F) and coldest in May (about 71°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (71°F) to its warmest (83°F).
Typical surface water temperature by month, from 26 field readings (2010–2023) via the EPA Water Quality Portal. See the full Slipbluff Lake water temperature breakdown →
Lake Details
Surface area
18 acres
No bathymetric survey has been published for Slipbluff Lake, so its depth is not documented here.
Stays via Stay22
Stays near Slipbluff Lake
Compare lakeside cabins, hotels, and vacation rentals near Slipbluff Lake in Decatur 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.
Top-rated places to stay near Slipbluff 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 Slipbluff Lake’s readings
Email me when new measurements post for this lake. Updates stay free.
Or email
Fishing Slipbluff Lake
Water Quality Trend: Worsening
Based on 4 years of monitoring (2021–2024).
Water clarity
Improving4 years
Phosphorus
Worsening+6 µg/L/yr4 years
Chlorophyll-a
Worsening+0.25 µg/L/yr4 years
Reservoir Info (USACE NID)
Slipbluff Lake is a man-made reservoir impounded by the Slip Bluff Park Dam (completed 1970), built primarily for recreation on the TR-POTTEROFF CREEK; earth-type dam, 33 ft tall and 333 ft long.
- Surface area
- 18 ac
- Normal storage
- 230 ac-ft
- Max storage
- 464 ac-ft
- Drainage area
- 0.44 sq mi
- Hazard class
- Low
- Owner
- Decatur County Conservation Board
Source: USACE National Inventory of Dams, NID ID IA00349 · Operator website · Matched by proximity (1 km)
Regulated Pollution Sources Nearby
5 EPA-permitted facilities operate within about 5 miles of Slipbluff Lake under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- Davis City, City Of Stp (Sirwa)Davis City · 2.9 mi away · NPDES IA0060232Recent violation
- Iowa Dot Rest Area #34 I35 LamoniLamoni · 0.2 mi away · NPDES IA0068934
- Procom, Inc.Lamoni · 2.2 mi away · NPDES IA0068144
- Chief Lamoni Motel-StpLamoni · 3.1 mi away · NPDES IA0069051
- Lamoni Industrial Park StpLamoni · 3.4 mi away · NPDES IA0070963
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 Decatur County
Frequently asked questions about Slipbluff Lake
Where is Slipbluff Lake?
- Slipbluff Lake is a lake in Decatur County, Iowa. Its water-quality measurements are published by Iowa DNR and shown on this page as reported.
What is the water quality of Slipbluff Lake?
- Slipbluff Lake in Decatur County, Iowa has water-quality measurements published by Iowa DNR, shown here as reported. Water clarity: 9 ft visibility. Phosphorus: 17.5 µg/L. Chlorophyll-a (algae): 4.5 µg/L. Surface area: 18 acres.
Is Slipbluff Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
What is the water temperature of Slipbluff Lake?
- Slipbluff Lake typically sits around 78°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.
Explore Slipbluff Lake across LakeQuality
More lakes in Iowa
Other Lakes in Iowa
Mesotrophic Lakes in Iowa
Where this data comes from
54 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_WQX54 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)
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
Regulated discharger data from EPA ECHO (ICIS-NPDES)