Iowa's Ambient Water Quality Monitoring and Assessment Program
Water Quality Assessments

The Water Quality Monitoring and Assessment Section of the Iowa Department of Natural Resources (IDNR) is responsible for the design, implementation and management of Iowa's Ambient Water Monitoring Programs. The purpose of these programs is to provide consistent, unbiased information about the condition of Iowa's surface and groundwater resources so that decisions regarding the development, management, and protection of these resources may be improved.

With physical and chemical monitoring, a "snapshot" in time is taken of the water's condition. A single sample does not provide very useful data, as a recent rainstorm, drought, fertilizer application, or any number of conditions may have influenced the condition of the water at the time the sample was collected. Many samples over a period of time are needed to get an accurate picture of the water quality of that waterbody.

Current monitoring program activities are guided by the 2016 Ambient Water Monitoring Strategy. In developing the strategy, the DNR held listening sessions with a variety of stakeholders to receive input relating to program usefulness and improvement opportunities. A complete listing of stakeholders and their input and recommendations for monitoring improvements are contained in the strategy document. The DNR also prepared a summary of its responses to stakeholder comments on the draft strategy.

Many different programs within the section help provide data and information, enabling the IDNR to make assessments of the water quality throughout the state. Data used for water quality assessments must meet the requirements of Iowa's Credible Data Law.

What We Do

Ambient Lake Monitoring

The Ambient Lake Monitoring program samples over 130 lakes in Iowa each summer. Each lake is sampled three times between May and September: once in early summer, once in mid-summer, and once in late summer/early fall. Data from this project are used to assess the health of our lakes and target individual lakes for restoration and watershed improvement activities. Monitoring is currently completed through a partnership with the Iowa State University Limnology Laboratory. Monitoring results for individual lakes are available in the  Iowa DNR's AQuIA database.

State Park Beach Monitoring

The IDNR beach monitoring program samples State Parks and participating city/county beaches each week throughout the summer for indicator bacteria and algal toxins. Beach monitoring is targeted at providing up to date information for recreating at our many beaches. A map with currently weekly monitoring results is available.

Ambient Biological Monitoring

Since 1994, the IDNR has sampled fish and benthic macroinvertebrates across the state to assess the biological integrity of Iowa's streams and rivers. Benthic macroinvertebrates are small animals, such as aquatic insects, crustaceans, leeches, and snails that live on the stream bottom. The numbers and types of aquatic organisms found in a stream are useful indicators of the stream's health because they reflect changes in water quality and habitat.

The BioNet online database contains all data collected as part of the biological assessment program. The Standard Operating Procedure for assessing Iowa's wadeable streams can be found in the Publications portion of BioNet.

A report titled Biological Assessment of Iowa's Wadeable Streams is available. The report describes a framework for conducting stream bioassessments and how it is used to evaluate the biological condition of Iowa's wadeable rivers and streams. The document also serves as a foundation for developing biological water quality standards for the protection of designated aquatic life uses and measuring progress toward the achievement of Federal Clean Water Act goals.

Water Quality Assessments

All of the data collected through the IDNR's Water Monitoring Program section and many other agencies is used to make an "assessment" of the water quality for a given stream. These assessments, known as the 305(b) Water Quality Reporting process, use quantitative data to determine the quality of Iowa's water resources.

These assessments are prepared under guidance provided by the US EPA under Section 305(b) of the Clean Water Act to estimate the extent to which Iowa's waterbodies meet the goals of the Clean Water Act and attain State water quality standards, and share this information with planners, citizens and other partners in basin planning and watershed management activities.

The assessments are prepared every two years, and can be found in the ADBNet online database. 

Ambient Stream Monitoring

Monthly ambient stream monitoring in a fixed network of sites across the state have been sampled for a variety of parameters. These data are processed into informational products for the public and resource managers, which can be used to develop strategies to protect and improve water quality in Iowa.

Ambient Wetland Monitoring

Wetlands are essential wildlife habitats and act as natural filters, trapping excess nutrients and sediment traveling downstream. A statewide monitoring program was developed to assess these valuable areas, and results from this monitoring will enable the IDNR to determine the ecological condition of wetlands while documenting the leading contaminants and stressors found in these systems.

Shallow Lakes Monitoring

Shallow Lake monitoring is targeted to show changes in water quality after restoration activities. Monitoring has shown dramatic increases in water clarity after restoration. Future monitoring activities will continue to document water quality and target waterbodies for future work.

Ambient Fish Tissue Monitoring

One of the primary public health concerns in regards to water quality is the suitability of the fish in our waters for human consumption. In Iowa, the Fisheries Bureau of the IDNR is responsible for issuing fish consumption advisories. The IDNR Water Quality Bureau is responsible for coordinating the annual collection of fish tissue for contaminant analysis and is also responsible for the preparation of data summaries.

The current Fish Consumption Advisories and fish tissue sampling methodology information can be found on the Fish Tissue Monitoring page.

Ambient Groundwater Monitoring

Over seventy-five percent of Iowans rely on groundwater as their primary source of drinking water. Assessments of Iowa’s groundwater quality and quantity are necessary to address public health concerns, help communities, industries, individuals, and ecosystems meet their water needs, and ensure the sustainability of this resource.

Fish Kill Tracking

The section also tracks fish kills throughout the state and maintains the Iowa DNR Fishkill Database.

Wasteload Allocation

A Wasteload Allocation (WLA) is the portion of a receiving water’s assimilative capacity that is allocated to one of its existing or future point sources of pollution. The IDNR develops WLAs for some construction projects and for facilities, as part of the NPDES permitting process, before they discharge treated wastewater (for example, domestic sewage treatment plants and industrial plants) into waters of the state. A WLA is calculated in order to assure that the permitted effluent limits meet applicable state Water Quality Standards.

Use Assessments and Use Attainability Analysis

The Use Assessment and Use Attainability Analysis (UA/UAA) staff gather field data and assess available information to determine the highest level of recreation and aquatic life uses a stream is capable of supporting and assigning the most appropriate recreational and aquatic life use classification for each stream in Iowa. The current priority is to collect information on those streams that are receiving a permitted discharge (e.g. wastewater treatment plant).

Section 401 Water Quality Certification

The IDNR has specific regulatory roles, when it comes to construction projects that may impact wetland; rivers; or streams, that are designed to protect these waters of the State. The IDNR’s role is different, but complimentary to the US Army Corps of Engineers (Corps) responsibilities.

A Section 401 Water Quality Certificate is IDNR's certification that a project will not violate state water quality standards and is required before the Corps of Engineers can issue a Section 404 permit.

Other Data Sources

More water monitoring data can be found in the following locations: