Eldred Sherwood Lake
Hancock County, Iowa23 acresView mapDirections
Iowa DNR publishes the water-quality measurements for Eldred Sherwood Lake. Here is what has been measured.
- Hypereutrophic
- Impaired · Pathogens (E. coli, fecal)
Eldred Sherwood Lake in Hancock County, Iowa has water-quality measurements published by Iowa DNR, shown here as reported. Water clarity: 3 ft visibility. Phosphorus: 89 µg/L. Chlorophyll-a (algae): 31.3 µg/L. Surface area: 23 acres.
Free interactive depth-contour map of Eldred Sherwood Lake, reaching a maximum surveyed depth of 21 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Iowa DNR.
Eldred Sherwood Lake is a 23-acre highly nutrient-loaded hypereutrophic lake in Hancock County, Iowa. Overall water quality is improving over recent sampling years. Compared to the 1 other monitored lakes in Hancock County, Eldred Sherwood Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, Iowa DNR, last sampled 2024-10-28. Methodology: how these readings are compared.
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, Eldred Sherwood Lake never exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 0% of 21 samples across 2 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 Eldred Sherwood 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 Eldred Sherwood Lake
These are the measurements Iowa DNR publishes for Eldred Sherwood 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 3 ft of visibility. Phosphorus 89 µg/L. Chlorophyll-a 31.3 µg/L. TSI 65.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 3ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 89µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | 31.3µg/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 Eldred Sherwood Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Eldred Sherwood Lake typically sits around 71°F at the surface in September. Summer average is about 72°F. Usually warmest in Jul (about 76°F) and coldest in May (about 60°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (60°F) to its warmest (76°F).
Typical surface water temperature by month, from 35 field readings (2010–2023) via the EPA Water Quality Portal. See the full Eldred Sherwood Lake water temperature breakdown →
Lake Details
Surface area
23 acres
No bathymetric survey has been published for Eldred Sherwood Lake, so its depth is not documented here.
Stays via Stay22
Stays near Eldred Sherwood Lake
Compare lakeside cabins, hotels, and vacation rentals near Eldred Sherwood Lake in Hancock 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 Eldred Sherwood Lake are listed below.
Top-rated places to stay near Eldred Sherwood 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 Eldred Sherwood Lake’s readings
Email me when new measurements post for this lake. Updates stay free.
Or email
Fishing Eldred Sherwood Lake
Water Quality Trend: Improving
Based on 4 years of monitoring (2021–2024).
Water clarity
Improving4 years
Phosphorus
Improving-22.88 µg/L/yr4 years
Chlorophyll-a
Stable+0.35 µg/L/yr4 years
Reservoir Info (USACE NID)
Eldred Sherwood Lake is a man-made reservoir impounded by the Eldred Sherwood Park Lake Dam (completed 1967), built primarily for other on the TR-EAST BRANCH IOWA RIVER; earth-type dam, 33 ft tall and 555 ft long.
- Surface area
- 23 ac
- Normal storage
- 220 ac-ft
- Max storage
- 360 ac-ft
- Drainage area
- 4.45 sq mi
- Hazard class
- Low
- Owner
- Hancock County Conservation Board
Source: USACE National Inventory of Dams, NID ID IA00438 · Operator website · Matched by proximity (0.05 km)
EPA Impairment Status
Eldred Sherwood 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-773 · Official waterbody report
Regulated Pollution Sources Nearby
2 EPA-permitted facilities operate within about 5 miles of Eldred Sherwood Lake under Clean Water Act (NPDES) discharge permits. 2 facilities have a reported Clean Water Act violation in the past three years.
- Goodell City Of StpGoodell · 2.5 mi away · NPDES IA0082562Recent violation
- Klemme City Of StpKlemme · 4.7 mi away · NPDES IA0038466Recent violation
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 Hancock County
Frequently asked questions about Eldred Sherwood Lake
Where is Eldred Sherwood Lake?
- Eldred Sherwood Lake is a lake in Hancock County, Iowa. Its water-quality measurements are published by Iowa DNR and shown on this page as reported.
What is the water quality of Eldred Sherwood Lake?
- Eldred Sherwood Lake in Hancock County, Iowa has water-quality measurements published by Iowa DNR, shown here as reported. Water clarity: 3 ft visibility. Phosphorus: 89 µg/L. Chlorophyll-a (algae): 31.3 µg/L. Surface area: 23 acres.
Is Eldred Sherwood Lake safe to swim in?
- Based on E. coli testing, Eldred Sherwood Lake never exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 0% of 21 samples across 2 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 Eldred Sherwood 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 Eldred Sherwood Lake?
- Eldred Sherwood Lake typically sits around 71°F at the surface in September, from 35 EPA Water Quality Portal field readings (2010–2023). That is a typical value for the month, not a live reading.
Explore Eldred Sherwood Lake across LakeQuality
More lakes in Iowa
Other Lakes in Iowa
Hypereutrophic Lakes in Iowa
Where this data comes from
82 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_WQX82 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
- 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)