Lake Geode is a 195-acre productive, nutrient-rich eutrophic lake in Des Moines County, Iowa. Water quality is graded F based on 2 sampling years through 2024. Overall water quality is declining over recent sampling years. Limited fish-species data available. Public access is available with 1 public boat landing. Compared to the 1 other monitored lakes in Des Moines County, Lake Geode ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, Iowa DNR, last sampled 2024-09-16. Grade methodology: LakeGrade methodology.
Watch Lake Geode water quality
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Swimming Safety
Based on E. coli testing, Lake Geode occasionally exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 8.9% of 45 samples across 3 seasons.
This is a historical summary of past testing, not a current condition — bacteria levels change quickly, especially after rain. Always check Iowa’s current beach and health-department advisories before swimming.
Water Quality Grade: F, Very Poor
Very murky, less than 2.1 ft of visibility. Chlorophyll-a: 30.5 µg/L. Trophic State Index: 65.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 2.1 ft | F |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | 30.5 µg/L | F |
| Trophic State Index (TSI) | 65 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 195 acres |
| Public Access | Yes |
Where to stay near Lake Geode
Compare lakeside cabins, hotels, and vacation rentals near Lake Geode in Des Moines 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.
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Fishing Lake Geode
Water Quality Trend: ↓ Declining
Based on 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | -0.012 m/yr | 4 |
| Chlorophyll-a | ↓ Declining | +10.4 µg/L/yr | 4 |
Recreation & Access
Water Temperature
Lake Geode averages about 78°F at the surface in summer, usually warmest in Jul (about 81°F) and coldest in May (about 71°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 23 field readings (2010–2023) via the EPA Water Quality Portal. See the full Lake Geode water temperature breakdown →
Location
County Ranking
Ranked #2 of 2 lakes in Des Moines County
Cleaner Lakes Within 30 Miles
Lake Geode holds Grade F. One nearby lake has a higher grade.
See full comparison →Nearby Lakes in Des Moines County
Explore Lake Geode across LakeGrade
More Iowa Lake Rankings
Other Grade F Lakes in Iowa
Eutrophic Lakes in Iowa
More records, surveys & data sources
Reservoir Info (USACE NID)
Lake Geode is a man-made reservoir impounded by the Geode Lake Dam (completed 1949), built primarily for recreation on the TR-SKUNK RIVER; earth-type dam, 59 ft tall and 1,060 ft long.
- Surface area
- 195 ac
- Normal storage
- 4,700 ac-ft
- Max storage
- 6,200 ac-ft
- Drainage area
- 15.35 sq mi
- Hazard class
- Significant
- Owner
- Iowa Department of Natural Resources
Source: USACE National Inventory of Dams, NID ID IA01347 · Operator website
EPA Impairment Status
Lake Geode is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit IA 03-SKU-896 · Official waterbody report
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth is a modeled estimate.
Regulated Pollution Sources Nearby
3 EPA-permitted facilities operate within about 5 miles of Lake Geode under Clean Water Act (NPDES) discharge permits. 2 facilities have a reported Clean Water Act violation in the past three years.
- Dnr Geode State ParkDanville · 0.8 mi away · NPDES IA0052732Recent violation
- Danville City Of StpDanville · 4.8 mi away · NPDES IA0025861Recent violation
- Dnr Geode State ParkDanville · 0.8 mi away · NPDES IA0066061
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.
Data Sources
Water quality data from the EPA Water Quality Portal
Impairment status from EPA ATTAINS 303(d) database
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Grading methodology based on Metropolitan Council standards
Public boat-access points from the USGS National Boat Ramps inventory
Most recent sample: 2024-09-16
Monitoring stations: 1