Briggs Woods Lake
Hamilton County, Iowa70 acresView mapDirections
Iowa DNR publishes the water-quality measurements for Briggs Woods Lake. Here is what has been measured.
- Hypereutrophic
- Impaired · Algal growth
- 23 ft max depth
- Public access
Briggs Woods Lake in Hamilton County, Iowa has water-quality measurements published by Iowa DNR, shown here as reported. Water clarity: 1.5 ft visibility. Phosphorus: 87 µg/L. Chlorophyll-a (algae): 59.1 µg/L. Surface area: 70 acres.
Free interactive depth-contour map of Briggs Woods Lake, reaching a maximum surveyed depth of 26 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Iowa DNR.
Briggs Woods Lake is a 70-acre highly nutrient-loaded hypereutrophic lake in Hamilton County, Iowa with an estimated average depth of about 23 feet. Overall water quality is declining over recent sampling years. Limited fish-species data available. Public access is available with 2 public boat landings. Compared to the 1 other monitored lakes in Hamilton County, Briggs Woods Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, Iowa DNR, last sampled 2024-10-30. Methodology: how these readings are compared.
What Briggs Woods Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch2 documented ramps
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. Briggs Woods Lake is listed impaired under Clean Water Act §303(d) (IR 5) for algal growth, pH / acidity, turbidity. Check local advisories before you swim.
Whether Briggs Woods 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 Briggs Woods Lake
These are the measurements Iowa DNR publishes for Briggs Woods 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 1.5 ft of visibility. Phosphorus 87 µg/L. Chlorophyll-a 59.1 µg/L. TSI 70.
| 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 | 87µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | 59.1µg/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. | 70 | Hypereutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Very high nutrients, dense algae, poor clarity
Ask about Briggs Woods Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Briggs Woods Lake typically sits around 73°F at the surface in September. Summer average is about 77°F. Usually warmest in Jul (about 82°F) and coldest in May (about 61°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (61°F) to its warmest (82°F).
Typical surface water temperature by month, from 32 field readings (2010–2023) via the EPA Water Quality Portal. See the full Briggs Woods Lake water temperature breakdown →
Lake Details
Max depth
~23 ft est.
Surface area
70 acres
Public access
Yes
Listed by Iowa DNR
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Iowa has not published bathymetry for Briggs Woods Lake.
Lake Size & Watershed
Watershed (drainage) area
17 sq mi
HydroLAKES / HydroSHEDS
Shoreline
2.2 mi
HydroLAKES / HydroSHEDS
Elevation
1,040 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.
Recreation & Access
- Briggs Wood ParkPublic
- Briggs Wood ParkPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Briggs Woods Lake
Compare lakeside cabins, hotels, and vacation rentals near Briggs Woods Lake in Hamilton 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 Briggs Woods Lake are listed below.
Top-rated places to stay near Briggs Woods Lake
Prices for Oct 23–25, 4 adults. Change dates on the map below.
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Fishing Briggs Woods Lake
Water Quality Trend: Worsening
Based on 5 years of monitoring (2020–2024).
Water clarity
Improving5 years
Phosphorus
Worsening+1.9 µg/L/yr4 years
Chlorophyll-a
Worsening+3.97 µg/L/yr5 years
Reservoir Info (USACE NID)
Briggs Woods Lake is a man-made reservoir impounded by the Briggs Woods Lake Dam (completed 1968), built primarily for recreation on the TR-BOONE RIVER; earth-type dam, 44 ft tall and 3,100 ft long.
- Surface area
- 70 ac
- Normal storage
- 1,310 ac-ft
- Max storage
- 2,100 ac-ft
- Drainage area
- 10.62 sq mi
- Hazard class
- Significant
- Owner
- Hamilton County Conservation Board
All listed purposes: Recreation;Water Supply.
Source: USACE National Inventory of Dams, NID ID IA00437 · Operator website
EPA Impairment Status
Briggs Woods 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 04-UDM-1255 · Official waterbody report
Regulated Pollution Sources Nearby
3 EPA-permitted facilities operate within about 5 miles of Briggs Woods Lake under Clean Water Act (NPDES) discharge permits, including 1 classified by the EPA as major discharger. 3 facilities have a reported Clean Water Act violation in the past three years.
- Webster City, City Of StpWebster City · 1.8 mi away · NPDES IA0036625MajorRecent violation
- Webster City Municipal Bldg.Webster City · 2.7 mi away · NPDES IA0066281Recent violation
- Kamrar City Of StpKamrar · 4.7 mi away · NPDES IA0069124Recent 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 Hamilton County
Frequently asked questions about Briggs Woods Lake
Where is Briggs Woods Lake?
- Briggs Woods Lake is a lake in Hamilton County, Iowa. Its water-quality measurements are published by Iowa DNR and shown on this page as reported.
What is the water quality of Briggs Woods Lake?
- Briggs Woods Lake in Hamilton County, Iowa has water-quality measurements published by Iowa DNR, shown here as reported. Water clarity: 1.5 ft visibility. Phosphorus: 87 µg/L. Chlorophyll-a (algae): 59.1 µg/L. Surface area: 70 acres.
Is Briggs Woods Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Briggs Woods Lake is listed impaired under Clean Water Act §303(d) (IR 5) for algal growth, pH / acidity, turbidity. Check local advisories before you swim.
What is the water temperature of Briggs Woods Lake?
- Briggs Woods Lake typically sits around 73°F at the surface in September, from 32 EPA Water Quality Portal field readings (2010–2023). That is a typical value for the month, not a live reading.
How deep is Briggs Woods Lake?
- No published bathymetric survey covers Briggs Woods Lake, 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 70 acres.
Are there boat ramps on Briggs Woods Lake?
- Briggs Woods Lake has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Briggs Wood Park, Briggs Wood Park. Public access is listed as yes.
Can I fish at Briggs Woods Lake?
- Briggs Woods Lake has 2 documented boat landings in the USGS National Boat Ramps inventory. 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 Briggs Woods Lake across LakeQuality
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Where this data comes from
79 measurements from 1 monitoring station, 2020–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Iowa DNR Surface Water Monitoring Data
21IOWA_WQX79 samples · 2020–2024
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)
Named boat-access points from the USGS National Boat Ramps inventory