Little Wood Reservoir
Blaine County, Idaho590 acresView mapDirections
Idaho DEQ publishes the water-quality measurements for Little Wood Reservoir. Here is what has been measured.
- Public access
- Limited data
Little Wood Reservoir in Blaine County, Idaho has water-quality measurements published by Idaho DEQ, shown here as reported. Phosphorus: 70 µg/L. Chlorophyll-a (algae): 30.2 µg/L. Surface area: 590 acres.
Little Wood Reservoir is a 590-acre lake in Blaine County, Idaho. Overall water quality is declining over recent sampling years. Limited fish-species data available. Public access is available with 1 public boat landing.
Source: EPA Water Quality Portal sampling records, IDEQ, last sampled 2021-07-15. Methodology: how these readings are compared.
Little Wood Reservoir covers about 590 acres in Blaine County. It has one public boat landing. If you are planning to stay, you can search lake houses and cabins around Little Wood Reservoir on Vrbo, or look for a hotel room near the lake on Booking.com or Expedia.
What Little Wood Reservoir is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Little Wood Reservoir is safe to swim in today is a call for the Idaho Department of Environmental Quality and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Little Wood Reservoir
These are the measurements Idaho DEQ publishes for Little Wood Reservoir, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
No clarity data. Phosphorus 70 µg/L. Chlorophyll-a 30.2 µg/L. TSI 65.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | No reading How deep a black-and-white disk stays visible from the surface. Higher is clearer. | |
| Total phosphorus | 70µg/L | Measured, not scored The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. |
| Chlorophyll-a (algae) | 30.2µg/L | Measured, not scored The green pigment in algae — a direct measure of how much algae is in the water. |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 65 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Little Wood Reservoir
Answers come straight from the public measurements and survey records on this page.
Lake Details
Surface area
590 acres
Public access
Yes
Listed by Idaho DEQ
No bathymetric survey has been published for Little Wood Reservoir, so its depth is not documented here.
Recreation & Access
- Little Wood ReservoirPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Little Wood Reservoir
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Fishing Little Wood Reservoir
Water Quality Trend: Worsening
Based on 13 years of monitoring (2012–2024).
Water clarity
Worsening11 years
Phosphorus
Worsening+1.98 µg/L/yr13 years
Chlorophyll-a
Worsening+7.79 µg/L/yr11 years
Reservoir Info (USACE NID)
Little Wood Reservoir is a man-made reservoir impounded by the Little Wood River Dam (completed 1939), built primarily for irrigation on the Little Wood River Malad River; earth-type dam, 129 ft tall and 3,100 ft long.
- Surface area
- 590 ac
- Normal storage
- 30,000 ac-ft
- Max storage
- 33,300 ac-ft
- Drainage area
- 273.98 sq mi
- Hazard class
- High
- Owner
- LITTLE WOOD RIVER IRRIGATION DISTRICT
Source: USACE National Inventory of Dams, NID ID ID00041 · Operator website · Matched by proximity (0.72 km)
Nearby Lakes in Blaine County
Frequently asked questions about Little Wood Reservoir
Where is Little Wood Reservoir?
- Little Wood Reservoir is a lake in Blaine County, Idaho. Its water-quality measurements are published by Idaho DEQ and shown on this page as reported.
What is the water quality of Little Wood Reservoir?
- Little Wood Reservoir in Blaine County, Idaho has water-quality measurements published by Idaho DEQ, shown here as reported. Phosphorus: 70 µg/L. Chlorophyll-a (algae): 30.2 µg/L. Surface area: 590 acres.
Is Little Wood Reservoir safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Are there boat ramps on Little Wood Reservoir?
- Little Wood Reservoir has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Little Wood Reservoir. Public access is listed as yes.
Can I fish at Little Wood Reservoir?
- Little Wood Reservoir has 1 documented boat landing in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Idaho's fish and wildlife agency, so check its current regulations before you go.
Explore Little Wood Reservoir across LakeQuality
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Where this data comes from
3 measurements from 1 monitoring station, 2021. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Bureau of Reclamation
1119USBR_WQX3 samples · 2021
Analytical methods
- Phosphorus by Single Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- Turbidity by Nephelometry
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
Named boat-access points from the USGS National Boat Ramps inventory