For purposes of developing stream/river water quality assessments for integrated reporting, three years of water quality data are typically used for both conventional pollutant parameters (e.g., indicator bacteria) and the less frequently monitored toxic parameters (e.g., toxic metals). Since the 2004 IR cycle, DNR has used a three-year data gathering period for streams, rivers, and beaches. For most assessments, the use of three years of data increases the number of samples upon which the decision on use support is based and helps address the problem of weather-related year-to-year fluctuations in water quality.
Due to the lower sampling frequency in Iowa’s ambient lake, biological, fish kill, and fish tissue monitoring programs, five years of data are used for developing IR assessments and for identifying Section 303(d) listings.
| Data Type |
Data Timeframe |
| Beach Sampling Data |
CY 2022 - 2024 |
| Stream/River Water Quality Data |
CY 2022 - 2024 |
| Lake Water Quality Data |
CY 2020 - 2024 |
| Biological Sampling Data |
CY 2020 - 2024* |
| Fish Kill Data |
CY 2020 - 2024 |
| Fish Tissue Sampling Data |
CY 2020 - 2024 |
| Continuous Dissolved Oxygen Sampling Data |
CY 2020 - 2024 |
| *Biological sites sampled in both 2019 and 2023 were also assessed. |
