Cooperator: Wisconsin
Department of Natural Resources
Project Chief: David J. Graczyk; Dale M. Robertson
Location: Statewide
Project Number: 9KP43
Period of Project: March 2001 to October 2007
updated 2/20/07
Problem
Excessive nutrient loss (primarily phosphorus and nitrogen) from watersheda
is frequently associated with water-quality problems in Wisconsin’s water
bodies. Implementation of the WDNR’s proposed agricultural performance
standards and prohibitions should decrease the risk of excessive nutrient loss
from croplands and livestock operations. Implementation of TMDLs and the enforcement
of phosphorus criteria would also reduce the problems caused by nutrients. The
expected water-quality improvements due to the application of agricultural performance
standards may vary due to possible differences in nutrient responses in each
water body, depending upon where the stream is located. In order to evaluate
the environmental benefits of the proposed performance standards and phosphorus
criteria, sufficient data need to be collected in various types of streams to
define the nutrient response.
Objective
The objectives of the project are to: (1) describe the water quality and biological
communities in streams throughout the state, (2) determine how phosphorus and
nitrogen concentrations impair the biological integrity of streams, (3) develop
a database that can be used to refine the phosphorus criteria for Wisconsin streams,
(4) determine how watershed characteristics affect the relations between phosphorus
and nitrogen concentrations in streams and the biological integrity of the streams,
and (5) improve our biological assessment of nutrient impairments by developing
a nutrient index of biological integrity.
Approach
The approach for the project is to collect water-quality
and biological-community data from streams throughout the state and statistically
determine if significant relations exist between a stream’s nutrient concentrations,
biological integrity, and watershed characteristics. Multivariate statistical
analyses will be used to sort out the importance of the many different variables.
Since these nutrient relations are expected to vary with stream size and the
location of the stream in the state, streams will be grouped by size, and by
four nutrient ecoregions and four nutrient zones. Streams will be divided into
wadeable and non-wadeable streams.
The variables in the statistical analysis
will include indicators of biological integrity, habitat characteristics, nutrient
concentrations, and specific watershed characteristics. The biological indicators
will include fish abundance and diversity, macroinvertebrate diversity, and periphyton
biomass. Water samples collected from the stream will be analyzed for total phosphorus,
dissolved phosphorus, nitrate, total Kjeldahl nitrogen, ammonia, turbidity, conductivity,
and suspended chlorophyll a. Watershed characteristics will include drainage-area
size, stream gradient, climate data, land use, annual runoff, surficial deposits
data, and soil characteristics types.
Approximately 160 small streams will be
monitored in the first year of the study. Approximately 80 larger wadeable streams
will be monitored in the second year of the study and approximately 40 larger
non-wadeable larger streams will be sampled in the third year of the study. The
fish and habitat data in the wadeable streams were collected using similar protocols
at all sites and the data are stored in a readily accessible database. A total
of six water-quality samples will be collected between the months of May and
October at each site. A flow measurement will be collected at the time of the
water-quality grab sample.
Progress (January 2006 to June 2006)
Completed the analysis examining the relations between watershed characteristics
and water quality, between water quality and diatom communities, between water
quality and macroinvertebrate and fish communities, and the analysis examined
the interrelations between all aspects of water quality and biological integrity
of streams. A final report was written describing the impact of phosphorus and
nitrogen concentrations on the biological integrity of wadeable streams in Wisconsin.
Preliminary analysis of the data collected on the non-wadeable streams will be
started.
Plans (June 2006 to December 2007)
Complete analysis of the data collected on the non-wadeable streams will be conducted.
A final report will be written describing the impact of phosphorus and nitrogen
concentrations on the biological integrity of non-wadeable streams in Wisconsin.
Report
Robertson, D. M., Graczyk, D. J., Garrison, P. J., Wang, L., LaLiberte, G., and
Bannerman, R., 2006, Nutrient Concentrations and Their Relations to the Biotic
Integrity of Wadeable Streams in Wisconsin: U.S. Geological Survey Professional
Paper 1722, 139 p.
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