Iatt Lake Southwest of Fairfield
Iatt Lake Southwest of Fairfield in Grant Parish County, Louisiana has a water quality grade of D (Nutrient-rich). Phosphorus: 100 µg/L. Surface area: 7100 acres.
- Area
- 7,100 acres
- Type
- Hypereutrophic
- Public access
- Yes
Grade D measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Iatt Lake Southwest of Fairfield →
Iatt Lake Southwest of Fairfield is a 7,100-acre highly nutrient-loaded hypereutrophic lake in Grant Parish County, Louisiana. Water quality is graded D based on 1 sampling years through 2022. Limited fish-species data available. Public access is available with 2 public boat landings. Compared to the 1 other monitored lakes in Grant Parish County, Iatt Lake Southwest of Fairfield ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2022-09-07. Grade methodology: LakeGrade methodology.
Watch Iatt Lake Southwest of Fairfield water quality
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Swimming Safety
Grade onlyLimited data
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum
Water Quality Grade: D (Nutrient-rich)
No clarity data. Phosphorus level: 100 µg/L. Trophic State Index: 71.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | 100 µg/L | Poor |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 71 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Where to stay near Iatt Lake Southwest of Fairfield
Compare lakeside cabins, hotels, and vacation rentals near Iatt Lake Southwest of Fairfield in Grant Parish County, Louisiana — 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 grade measures nutrients and algae, not lodging — cabins and rentals around Iatt Lake Southwest of Fairfield are listed below.
Top-rated places to stay near Iatt Lake Southwest of Fairfield
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Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 7,100 acres |
| Public Access | Yes |
No bathymetric survey has been published for Iatt Lake Southwest of Fairfield, so its depth is not documented here.
Recreation & Access
- Dam LandingPublic
- Hydes LandingPublic
Named access points from the USGS National Boat Ramps inventory, snapped within 5 km. More lakes with boat ramps
Fishing Iatt Lake Southwest of Fairfield
Reservoir Info (USACE NID)
Iatt Lake Southwest of Fairfield is a man-made reservoir impounded by the Iatt Lake Dam (completed 1956), built primarily for recreation on the Bayou Rigolette; earth-type dam, 36 ft tall and 5,310 ft long.
- Surface area
- 7,100 ac
- Normal storage
- 31,000 ac-ft
- Max storage
- 167,000 ac-ft
- Drainage area
- 242 sq mi
- Hazard class
- High
- Owner
- State of Louisiana
Source: USACE National Inventory of Dams, NID ID LA00018 · Operator website · Matched by proximity (0.43 km)
EPA Impairment Status
Iatt Lake Southwest of Fairfield is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit LA101302_00 · Official waterbody report · Matched by proximity (0.01 km)
County Ranking
Ranked #1 of 2 lakes in Grant Parish County
Nearby Lakes in Grant Parish County
Frequently asked questions about Iatt Lake Southwest of Fairfield
Where is Iatt Lake Southwest of Fairfield?
- Iatt Lake Southwest of Fairfield is a lake in Grant Parish County, Louisiana. LakeQuality grades it D for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Iatt Lake Southwest of Fairfield?
- Iatt Lake Southwest of Fairfield in Grant Parish County, Louisiana has a water quality grade of D (Nutrient-rich). Phosphorus: 100 µg/L. Surface area: 7100 acres.
Is Iatt Lake Southwest of Fairfield safe to swim in?
- Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum. Iatt Lake Southwest of Fairfield has a water quality grade of D (Nutrient-rich). Always check local health department advisories before swimming.
Are there boat ramps on Iatt Lake Southwest of Fairfield?
- Iatt Lake Southwest of Fairfield has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Dam Landing, Hydes Landing. Public access is listed as yes.
Explore Iatt Lake Southwest of Fairfield across LakeGrade
More Louisiana Lake Rankings
Other Grade D Lakes in Louisiana
LaSalle Parish County · Nutrient-rich
Catahoula Parish County · Nutrient-rich
Beauregard Parish County · Nutrient-rich
Richland Parish County · Nutrient-rich
Franklin Parish County · Nutrient-rich
Catahoula Parish County · Nutrient-rich
Hypereutrophic Lakes in Louisiana
Where this data comes from
21 measurements from 1 monitoring station, 2021–2022. Retrieved from the EPA Water Quality Portal on 2026-08-21.
Collected and reported by
- LDEQ/Water Planning and Assessment (Louisiana)
LADEQWPD_WQX21 samples · 2021–2022
Analytical methods
- Total Phosphorus After Block Digestion
- 2130 B ~ Nephelometric Method
Monitoring station identifiers (1)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
Named boat-access points from the USGS National Boat Ramps inventory