Cascade R W of Sugarloaf Island Lake
Valley County, IdahoView mapDirections
Nutrients and algae run above the regional average.
↓ down from B at the last regrade
- Eutrophic
- Impaired · Nutrients (phosphorus, nitrogen)
- #8 of 9 in the county
- Public access
Cascade R W of Sugarloaf Island Lake in Valley County, Idaho has a water quality grade of D (Nutrient-rich). Water clarity: 8.2 ft visibility. Phosphorus: 28.5 µg/L. Chlorophyll-a (algae): 7.5 µg/L.
- Clarity
- 8.2 ft
- Type
- Eutrophic
- Phosphorus
- 28.5 µg/L
- Chlorophyll-a
- 7.5 µg/L
- Trend
- ↑ Improving
- Public access
- Yes
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Stays near Cascade R W of Sugarloaf Island Lake
Compare lakeside cabins, hotels, and vacation rentals near Cascade R W of Sugarloaf Island Lake in Valley County, Idaho — 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 Cascade R W of Sugarloaf Island Lake are listed below.
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Cascade R W of Sugarloaf Island Lake is a productive, nutrient-rich eutrophic lake in Valley County, Idaho. Water quality is graded D based on 2 sampling years through 2022. Overall water quality is improving over recent sampling years. Limited fish-species data available. Public access is available with 1 public boat landing. Compared to the 8 other monitored lakes in Valley County, Cascade R W of Sugarloaf Island Lake ranks #8 for water quality.
Source: EPA Water Quality Portal sampling records, IDEQ, last sampled 2022-09-22. Grade methodology: LakeQuality methodology.
What Cascade R W of Sugarloaf Island Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
Swimming Safety
Grade onlyElevated nutrients
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.
The D is nutrients and algae, not a swimming clearance. Cascade R W of Sugarloaf Island Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for nutrients (phosphorus, nitrogen), pH / acidity. Check local advisories before you swim.
Water Quality Grade: D (Nutrient-rich)
Moderate clarity, visible to about 8.2 ft. Phosphorus 28.5 µg/L. Chlorophyll-a 7.5 µg/L. TSI 50. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 8.2 ft | Not graded |
| Phosphorus | 28.5 µg/L | Fair |
| Chlorophyll-a (Algae) | 7.5 µg/L | Poor |
| Trophic State Index (TSI) | 50 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Recreation & Access
- SugarloafPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fishing Cascade R W of Sugarloaf Island Lake
Water Quality Trend: ↑ Improving
Based on 7 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.07 m/yr | 7 |
| Phosphorus | ↑ Improving | -1.7 µg/L/yr | 7 |
| Chlorophyll-a | ↓ Declining | +0.51 µg/L/yr | 7 |
EPA Impairment Status
Cascade R W of Sugarloaf Island Lake is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit ID17050123SW007L_0L · Official waterbody report · Matched by proximity (1.88 km)
County Ranking
Ranked #8 of 9 lakes in Valley County
Nearby Lakes in Valley County
Frequently asked questions about Cascade R W of Sugarloaf Island Lake
Where is Cascade R W of Sugarloaf Island Lake?
- Cascade R W of Sugarloaf Island Lake is a lake in Valley County, Idaho. LakeQuality grades it D for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Cascade R W of Sugarloaf Island Lake?
- Cascade R W of Sugarloaf Island Lake in Valley County, Idaho has a water quality grade of D (Nutrient-rich). Water clarity: 8.2 ft visibility. Phosphorus: 28.5 µg/L. Chlorophyll-a (algae): 7.5 µg/L.
Is Cascade R W of Sugarloaf Island Lake safe to swim in?
- The D is nutrients and algae, not a swimming clearance. Cascade R W of Sugarloaf Island Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for nutrients (phosphorus, nitrogen), pH / acidity. Check local advisories before you swim.
Are there boat ramps on Cascade R W of Sugarloaf Island Lake?
- Cascade R W of Sugarloaf Island Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Sugarloaf. Public access is listed as yes.
Explore Cascade R W of Sugarloaf Island Lake across LakeQuality
4 thermal springs within 14.4 mi, nearest Arling Hot Spring
Species activity outlook by water temperature and season
Where to stay at Idaho's top lakes, each with its grade
High nutrients, frequent algae, reduced clarity
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Other Grade D Lakes in Idaho
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Where this data comes from
82 measurements from 1 monitoring station, 2012–2022. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Bureau of Reclamation
1119USBR_WQX82 samples · 2012–2022
Analytical methods
- Depth, Secchi disk depth
- Zebra/Quagga Mussel APHA 10200G Modified
- Phosphorus by Single Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- Turbidity by Nephelometry
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