Lake Darling Max Depth
Washington County, Iowa304 acresView mapDirections
Iowa DNR publishes the water-quality measurements for Lake Darling Max Depth. Here is what has been measured.
- Hypereutrophic
- Impaired · Algal growth
- Public access
Lake Darling Max Depth in Washington County, Iowa has water-quality measurements published by Iowa DNR, shown here as reported. Water clarity: 1.6 ft visibility. Phosphorus: 226 µg/L. Chlorophyll-a (algae): 60.5 µg/L. Surface area: 304 acres.
Free interactive depth-contour map of Lake Darling Max Depth, reaching a maximum surveyed depth of 18 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Iowa DNR.
Lake Darling Max Depth is a 304-acre highly nutrient-loaded hypereutrophic lake in Washington County, Iowa. Water clarity is declining over recent sampling years. Limited fish-species data available. Public access is available.
Source: EPA Water Quality Portal sampling records, Iowa DNR, last sampled 2024-08-26. 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, Lake Darling Max Depth never exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 0% of 5 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 Lake Darling Max Depth 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 Darling Max Depth
These are the measurements Iowa DNR publishes for Lake Darling Max Depth, 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 1.6 ft of visibility. Phosphorus 226 µg/L. Chlorophyll-a 60.5 µg/L. TSI 75.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 1.6ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 226µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | 60.5µg/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. | 75 | Hypereutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Very high nutrients, dense algae, poor clarity
Ask about Lake Darling Max Depth
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Lake Darling Max Depth typically sits around 69°F at the surface in September. Summer average is about 78°F. Usually warmest in Jun (about 79°F) and coldest in Sep (about 69°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (69°F) to its warmest (79°F).
Typical surface water temperature by month, from 17 field readings (2015–2023) via the EPA Water Quality Portal. See the full Lake Darling Max Depth water temperature breakdown →
Lake Details
Surface area
304 acres
Public access
Yes
Listed by Iowa DNR
No bathymetric survey has been published for Lake Darling Max Depth, so its depth is not documented here.
Stays via Stay22
Stays near Lake Darling Max Depth
Compare lakeside cabins, hotels, and vacation rentals near Lake Darling Max Depth in Washington 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 Darling Max Depth are listed below.
Top-rated places to stay near Lake Darling Max Depth
Prices for Oct 23–25, 4 adults. Change dates on the map below.
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Fishing Lake Darling Max Depth
Water Quality Trend: Stable
Based on 4 years of monitoring (2021–2024).
Water clarity
Worsening4 years
Phosphorus
Improving-5.1 µg/L/yr4 years
Chlorophyll-a
Stable+0.69 µg/L/yr4 years
Reservoir Info (USACE NID)
Lake Darling Max Depth is a man-made reservoir impounded by the Lake Darling Dam (completed 1950), built primarily for recreation on the HONEY CREEK; earth-type dam, 47 ft tall and 1,230 ft long.
- Surface area
- 304 ac
- Normal storage
- 3,154 ac-ft
- Max storage
- 9,823 ac-ft
- Drainage area
- 19.64 sq mi
- Hazard class
- Significant
- Owner
- Iowa Department of Natural Resources
Source: USACE National Inventory of Dams, NID ID IA01381 · Operator website · Matched by proximity (0.2 km)
EPA Impairment Status
Lake Darling Max Depth 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 03-SKU-924 · Official waterbody report
Nearby Lakes in Washington County
Frequently asked questions about Lake Darling Max Depth
Where is Lake Darling Max Depth?
- Lake Darling Max Depth is a lake in Washington 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 Darling Max Depth?
- Lake Darling Max Depth in Washington County, Iowa has water-quality measurements published by Iowa DNR, shown here as reported. Water clarity: 1.6 ft visibility. Phosphorus: 226 µg/L. Chlorophyll-a (algae): 60.5 µg/L. Surface area: 304 acres.
Is Lake Darling Max Depth safe to swim in?
- Based on E. coli testing, Lake Darling Max Depth never exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 0% of 5 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 Lake Darling Max Depth 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 Lake Darling Max Depth?
- Lake Darling Max Depth typically sits around 69°F at the surface in September, from 17 EPA Water Quality Portal field readings (2015–2023). That is a typical value for the month, not a live reading.
Can I fish at Lake Darling Max Depth?
- Public access to Lake Darling Max Depth is listed as yes on the lake record. Seasons, size and bag limits, and whether you need a license are set by Iowa's fish and wildlife agency, so check its current regulations before you go.
Explore Lake Darling Max Depth across LakeQuality
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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
Impairment status from EPA ATTAINS 303(d) database