Lake Hendricks
Howard County, Iowa50 acresView mapDirections
Iowa DNR publishes the water-quality measurements for Lake Hendricks. Here is what has been measured.
- Hypereutrophic
- Impaired · Algal growth
- 23 ft max depth
Lake Hendricks in Howard County, Iowa has water-quality measurements published by Iowa DNR, shown here as reported. Water clarity: 1.5 ft visibility. Phosphorus: 108 µg/L. Chlorophyll-a (algae): 99.1 µg/L. Surface area: 50 acres.
Free interactive depth-contour map of Lake Hendricks, reaching a maximum surveyed depth of 14 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Iowa DNR.
Lake Hendricks is a 50-acre highly nutrient-loaded hypereutrophic lake in Howard County, Iowa with an estimated average depth of about 23 feet. Overall water quality is declining over recent sampling years.
Source: EPA Water Quality Portal sampling records, Iowa DNR, last sampled 2024-10-21. Methodology: how these readings are compared.
Lake Hendricks covers about 50 acres in Howard County. If you are planning to stay, you can search lake houses and cabins around Lake Hendricks on Vrbo, or look for a hotel room near the lake on Booking.com or Expedia.
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. Lake Hendricks is listed impaired under Clean Water Act §303(d) (IR 5) for algal growth. Check local advisories before you swim.
Whether Lake Hendricks 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 Lake Hendricks
These are the measurements Iowa DNR publishes for Lake Hendricks, 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 1.5 ft of visibility. Phosphorus 108 µg/L. Chlorophyll-a 99.1 µg/L. TSI 73.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 1.5ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 108µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | 99.1µg/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. | 73 | Hypereutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Very high nutrients, dense algae, poor clarity
Ask about Lake Hendricks
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Lake Hendricks typically sits around 71°F at the surface in September. Summer average is about 77°F. Usually warmest in Jul (about 81°F) and coldest in Sep (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 (81°F).
Typical surface water temperature by month, from 26 field readings (2010–2023) via the EPA Water Quality Portal. See the full Lake Hendricks water temperature breakdown →
Lake Details
Max depth
~23 ft est.
Surface area
50 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 Lake Hendricks.
Lake Size & Watershed
Watershed (drainage) area
12 sq mi
HydroLAKES / HydroSHEDS
Shoreline
1.3 mi
HydroLAKES / HydroSHEDS
Elevation
1,214 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 Lake Hendricks
Compare lakeside cabins, hotels, and vacation rentals near Lake Hendricks in Howard 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 Lake Hendricks are listed below.
Top-rated places to stay near Lake Hendricks
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 →
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Fishing Lake Hendricks
Water Quality Trend: Worsening
Based on 4 years of monitoring (2021–2024).
Water clarity
Worsening4 years
Phosphorus
Worsening+11.5 µg/L/yr4 years
Chlorophyll-a
Worsening+28.29 µg/L/yr4 years
Reservoir Info (USACE NID)
Lake Hendricks is a man-made reservoir impounded by the Lake Hendricks Dam (completed 1960), built primarily for recreation on the TR-WAPSIPINICON RIVER; earth-type dam, 30 ft tall and 2,375 ft long.
- Surface area
- 50 ac
- Normal storage
- 500 ac-ft
- Max storage
- 960 ac-ft
- Drainage area
- 1.88 sq mi
- Hazard class
- Significant
- Owner
- Howard County Conservation Board
Source: USACE National Inventory of Dams, NID ID IA00495 · Operator website
EPA Impairment Status
Lake Hendricks 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.
Source: EPA ATTAINS assessment unit IA 01-WPS-356 · Official waterbody report
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Lake Hendricks under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- Riceville City Of StpRiceville · 1.2 mi away · NPDES IA0032514Recent 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 Howard County
Frequently asked questions about Lake Hendricks
Where is Lake Hendricks?
- Lake Hendricks is a lake in Howard County, Iowa. Its water-quality measurements are published by Iowa DNR and shown on this page as reported.
What is the water quality of Lake Hendricks?
- Lake Hendricks in Howard County, Iowa has water-quality measurements published by Iowa DNR, shown here as reported. Water clarity: 1.5 ft visibility. Phosphorus: 108 µg/L. Chlorophyll-a (algae): 99.1 µg/L. Surface area: 50 acres.
Is Lake Hendricks safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Lake Hendricks is listed impaired under Clean Water Act §303(d) (IR 5) for algal growth. Check local advisories before you swim.
What is the water temperature of Lake Hendricks?
- Lake Hendricks typically sits around 71°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.
How deep is Lake Hendricks?
- No published bathymetric survey covers Lake Hendricks, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 23 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 50 acres.
Explore Lake Hendricks across LakeQuality
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Where this data comes from
68 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_WQX68 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
Impairment status from EPA ATTAINS 303(d) database
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)