Dr. Matt HelmersAssistant Professor and Extension

Agricultural EngineerDept . of Agricultural and Biosystems

EngineeringIowa State University

How is water quality measured? Who measures it?

What do we mean by “water quality”

Water quality is the measure of the suitability of water for a particular use based on physical, chemical, and biological characteristics.

Why do we measure water quality?

To ensure the water is safe for the intended use– Fishing– Swimming– Drinking – Agricultural use– Aquatic life

To make sure the quality of the water is meeting some determined criteria

To understand the impacts of land management practices or changes

How do we measure water quality?

Some aspects determined right in the stream– Flow– Temperature– pH– Dissolved oxygen– Electrical conductivity

Collection of water sample and analysis in the laboratory– Nutrients– Sediment– Bacteria– Etc.

Monitoring site on Upper Maquoketa River; northeast Iowa, above Backbone State Park (1999-2001)

ISCO flow-meter and auto-sampler in insulated enclosure

Flow and sampling set-up/Gilmore City site

Subsurface Flow – Timing of Flow

If drainage main is undersized problems occur

Subsurface Flow – Timing of Flow

Surface Runoff – Small Watersheds with Detailed Sampling

Surface Runoff – Small Watersheds with Detailed Sampling

How do we setup a monitoring scheme?

Depends on contaminant?– For nitrate grab samples on some set

schedule may be appropriate– For constituents primarily transported

during high-flow events more frequent sampling or automated sampling may be necessary

Monitoring sites on Upper Maquoketa River (1999-2001)northeast Iowa, 68% row-crop/significant subsurface drainage

Trends during runoff events of may 1-14, 2001 at Site 4.

0

2

4

6

8

10

12

14

16

18

1-May-01 4-May-01 7-May-01 11-May-01 14-May-010

2

4

6

8

10

12

14

16

18

Q (mm/day)NO3-N

Trends during runoff events of May 1-15, 2001, Site 4

0

2

4

6

8

10

12

14

16

18

1-May-01 4-May-01 7-May-01 11-May-01 14-May-010

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

Q (mm/day)Total P (filtered)

Does pollutant of concern impact ability to detect changes?

In Upper Midwest significant portion of nitrogen inputs to the stream may have fairly defined source from the tile lines – reducing nitrate to some acceptable level from drains may be relatively quickly reflected in watershed N-levels

Phosphorus source may be both field and in-stream which may greatly impact ability to detected impacts of practices changes on watershed P-levels

Monitoring Water Quality Checklist

1.Identify your watershed. 2.Choose between the types of monitoring. 3.Get expert help, including training and equipment. 4.Choose site(s) to collect samples. 5.Collect, organize, and analyze data. 6.Report your results to agencies and the public. 7.Maintain quality control.

Overview

To get a general idea of water quality conditions voluntary water monitoring may be appropriate

If the goal is to document effects of practices or practice changes a more detailed monitoring protocol would be necessary since would need samples over various conditions with corresponding analysis that has a high degree of precision.

Who monitors water quality?

Academia Federal and state agencies (e.g. U.S.G.S. and IA

DNR) Watershed groups Volunteer groups (e.g. IOWATER)

Links for additional information

National Water Quality Monitoring Council– http://acwi.gov/monitoring/index.html

http://www.epa.gov/owow/monitoring/monintr.html

http://iaspub.epa.gov/waters10/w305b_report_control.get_report?p_state=IA&p_cycle=#impairment