Walter E Long Lake Mid Lake
Travis County, Texas1,269 acresView mapDirections
Nutrients and algae run above the regional average.
↓ down from C at the last regrade
- Eutrophic
- #2 of 3 in the county
- Limited data
Walter E Long Lake Mid Lake in Travis County, Texas has a water quality grade of D (Nutrient-rich). Water clarity: 3.6 ft visibility. Phosphorus: 30 µg/L. Chlorophyll-a (algae): 15.7 µg/L. Surface area: 1269 acres.
- Clarity
- 3.6 ft
- Area
- 1,269 acres
- Type
- Eutrophic
- Phosphorus
- 30 µg/L
- Chlorophyll-a
- 15.7 µg/L
- Trend
- ↑ Improving
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Stays near Walter E Long Lake Mid Lake
Compare lakeside cabins, hotels, and vacation rentals near Walter E Long Lake Mid Lake in Travis County, Texas — 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 Walter E Long Lake Mid Lake are listed below.
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Watch Walter E Long Lake Mid Lake’s letter
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Walter E Long Lake Mid Lake is a 1,269-acre productive, nutrient-rich eutrophic lake in Travis County, Texas. Water quality is graded D based on 2 sampling years through 2024. Overall water quality is improving over recent sampling years. Compared to the 2 other monitored lakes in Travis County, Walter E Long Lake Mid Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, TCEQ, last sampled 2024-07-31. Grade methodology: LakeQuality methodology.
What Walter E Long Lake Mid Lake is good for
From access and monitoring records, not editorial picks.
- Big water1,269 acres
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.
The D is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
Water Quality Grade: D (Nutrient-rich)
Murky, only visible to about 3.6 ft. Phosphorus 30 µg/L. Chlorophyll-a 15.7 µg/L. TSI 57. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 3.6 ft | Not graded |
| Phosphorus | 30 µg/L | Good |
| Chlorophyll-a (Algae) | 15.7 µg/L | Poor |
| Trophic State Index (TSI) | 57 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 1,269 acres |
No bathymetric survey has been published for Walter E Long Lake Mid Lake, so its depth is not documented here.
Fishing Walter E Long Lake Mid Lake
Water Quality Trend: ↑ Improving
Based on 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.185 m/yr | 4 |
| Phosphorus | ↑ Improving | -6.43 µg/L/yr | 3 |
| Chlorophyll-a | ↑ Improving | -3.36 µg/L/yr | 4 |
Reservoir Info (USACE NID)
Walter E Long Lake Mid Lake is a man-made reservoir impounded by the Decker Creek Dam (completed 1967), built primarily for recreation on the Decker Creek; earth-type dam, 75 ft tall and 6,390 ft long.
- Surface area
- 1,269 ac
- Normal storage
- 33,940 ac-ft
- Max storage
- 45,200 ac-ft
- Drainage area
- 9.3 sq mi
- Hazard class
- High
- Owner
- CITY OF AUSTIN
All listed purposes: Recreation;Other.
Source: USACE National Inventory of Dams, NID ID TX01089 · Operator website · Matched by proximity (0.22 km)
County Ranking
Ranked #2 of 3 lakes in Travis County
Nearby Lakes in Travis County
Frequently asked questions about Walter E Long Lake Mid Lake
Where is Walter E Long Lake Mid Lake?
- Walter E Long Lake Mid Lake is a lake in Travis County, Texas. LakeQuality grades it D for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Walter E Long Lake Mid Lake?
- Walter E Long Lake Mid Lake in Travis County, Texas has a water quality grade of D (Nutrient-rich). Water clarity: 3.6 ft visibility. Phosphorus: 30 µg/L. Chlorophyll-a (algae): 15.7 µg/L. Surface area: 1269 acres.
Is Walter E Long Lake Mid Lake safe to swim in?
- The D is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
Explore Walter E Long Lake Mid Lake across LakeQuality
10.1 mi away · 15 ft
10.3 mi away · cable-pulled, no boat wake
Species activity outlook by water temperature and season
Where to stay at Texas's top lakes, each with its grade
High nutrients, frequent algae, reduced clarity
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Where this data comes from
28 measurements from 1 monitoring station, 2020–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Texas Commission on Environmental Quality
TCEQMAIN28 samples · 2020–2024
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.