Topical Teams, NAWQA
Project Title: Topical Teams, NAWQA
Project Number: 4571CRN
Project Chief: Moulton, Stephen R.
Project Start Date: 01-OCT-2006
Project End Date:
Project Objectives
The USGS National Water-Quality Assessment (NAWQA) Program addresses three long-term goals:
(1) Describe the status and trends in the quality of a large, representative part of the Nation's surface-water and groundwater
resources.
(2) Provide an improved understanding of the primary natural factors and human activities affecting these conditions.
(3) Provide information that supports development and evaluation of management, regulatory, and monitoring decisions
by other Federal, State, and local agencies.
(1) Sources and Transport of Agricultural Chemicals
What are the dominant sources and transport mechanisms of the most frequently occurring pesticides (including
agricultural VOCs) and nutrients in streams and shallow ground water within agricultural areas and what are the effects of
physiographic conditions and agricultural management practices on transport?
(2) Effects of Nutrient Enrichment on Agricultural Streams
1. Determine the total algal biomass and the abundance, type, and diversity of algal and aquatic invertebrate
communities in streams with different nutrient conditions, watershed characteristics, habitat, climate, and other natural
factors.
2. Determine the interrelations among nutrient conditions, algal communities, and stream metabolism, which is defined
as the gain and loss in dissolved oxygen associated with photosynthesis and plant and animal respiration. Adequate
levels of dissolved oxygen are critical to fish and other aquatic life.
3. Determine the transport, chemical transformation, and retention of nutrients (referred to as "nutrient cycling") in the
water column and surrounding sediments, and resulting effects on biological communities in stream reaches. Such cycling
differs in different geologic and hydrologic settings, and is controlled, in large part, by ground-water and surface-water
interactions.
4. Determine the extent to which associations between nutrient conditions and biological communities occur over
geographic regions that share common natural features, landscape characteristics, and biological communities.
(3) Transport of Contaminants to Public Water-Supply Wells
What processes govern the transport and concentrations of VOCs, pesticides, trace elements and nitrate from the land
surface through the unsaturated zone and in recently recharged shallow ground as it moves to underlying aquifers and
water-supply wells used for drinking water?
(4) Mercury Accumulation in Aquatic Organisms
What controls the movement of mercury from sources to its accumulation in aquatic organisms? The general objective is
to determine the effects of source strength, mercury cycling (especially methylation and demethylation), and food-web
interactions (food-web complexity) on bioaccumulation of mercury in fish in stream ecosystems. In other words, we seek
to determine environmental characteristics that are associated with a range of methylmercury contamination in fish.
(5) Effects Urbanization on Stream Ecosystems
How do the hydrologic, geomorphic, chemical, and biological characteristics of stream ecosystems respond to land-use
changes associated with urbanization and how do these responses vary across environmental settings?
Strategy and Approach
(1) Sources and Transport of Agricultural Chemicals
(2) Effects of Nutrient Enrichment on Agricultural Streams
Large-Scale Synoptic Studies
Streamflow, nutrient concentrations and other chemical characteristics, dissolved-oxygen concentrations, biological
communities, and stream and riparian habitat are assessed at selected sites within each Study Unit. Data from these
one-time assessments will be used to define relations among nutrients, stream metabolism, and biological communities in
diverse environmental settings, and to aid in statistical analyses for regionalization of nutrient conditions.
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U.S. Department of the Interior |
U.S. Geological Survey
