Watershed Classification as a Tool to Partition Variance in Nutrient- Biological Response Relationships
Abstract
Refining effects-based nutrient water quality criteria requires the partitioning of variation in nutrient-response relationships, including responses related to algae and dissolved oxygen, among stream types. In addition to nutrients, algal accrual rate can be limited by shading, herbivory, and the instream flow regime. For example, moderate flow rates can stimulate nutrient uptake, while frequent spates can scour algal biomass. Furthermore, algal accrual affects instream dissolved oxygen through primary production and instream respiration. To better understand the effects of nutrients on Upper Midwest streams, all subwatersheds at the HUC12 scale have been characterized for climatic, soils, geomorphology, andland-use/land-cover variables expected to control flow regime, and subjected to a nonparametric cluster analysis to identify unique hydrologic classes. A regional database also has been constructed comprising historical monitoring data for stream hydrology, water quality, habitat, algal biomass, and algal, macro-invertebrate, and fish community composition. Relationships between nutrients and minimum dissolved oxygen levels, BOD, periphyton or plankton biomass, and between nutrients and aquatic community metrics are being examined for differences in sensitivity across the identified watershed classes. This abstract does not necessarily reflect EPA policy.
- Publication:
-
AGU Spring Meeting Abstracts
- Pub Date:
- May 2005
- Bibcode:
- 2005AGUSMNB14E..02D
- Keywords:
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- 0400 Biogeosciences;
- 1800 HYDROLOGY;
- 1806 Chemistry of fresh water