Toxic algae in Ulster County, New York
13 lakes and waterways have harmful algal bloom reports in New York's official data.
Lakes with bloom history
| Lake | Years with reports | Most recent |
|---|---|---|
| Chodikee Lake | 7 | 2025 |
| Wallkill River | 7 | 2025 |
| Ashokan Reservoir | 3 | 2024 |
| Rondout Creek | 3 | 2025 |
| Rondout Reservoir | 2 | 2023 |
Other waterbodies with a report
These have one or two reports in a single year, so there isn't enough history for a page of their own yet.
- Davis Lake (2020)
- Esopus Creek (2017)
- Fourth Lake (2025)
- Lower Esopus Creek (2025)
- Quassaic Creek (2022)
- Seewackamano Lake (2020)
- Tillson Lake (2015)
- Ulster Heights Lake (2025)
Source: New York State Department of Environmental Conservation (DEC), official data. For current conditions see the NYHABS map.