8226

• UCREFRP Catalog Number: 8226
• Author: Shelton, L. R.
• Title: Field Guide for Collecting and Processing Stream-Water Samples for the National Water-Quality Assessment Program.
• USFW Year: 1994.
• USFW - Doc Type: 94-445,
• Copyright Material: NO

OVERVIEW OF WATER-COLUMN STUDY DESIGN

Water-Column Studies in NA WQA focus on assessing physical and chemical characteristics of stream
water, including suspended sediment, dissolved solids, major ions and metals, nutrients, organic carbon,
and dissolved pesticides, and on relating these characteristics to hydrologic conditions, sources, and
transport. The sampling designs for Water-Column Studies rely on coordinated sampling of varying
intensity and scope at two general types of sites, Integrator Sites and Indicator Sites. Integrator Sites are
chosen to represent water-quality conditions of streams and rivers in heterogeneous large basins that often
are affected by complex combinations of land-use settings, point sources, and natural influences. Indicator
Sites, in contrast, are chosen to represent water-quality conditions of streams in relatively homogeneous
and usually smaller basins associated with specific individual environmental settings (for example, a
particular combination of land-use and geological setting).

Water-column conditions are assessed by three primary sampling strategies employed at the selected
Integrator and Indicator Sites:

1. Basic Fixed-Site assessments characterize the spatial and temporal distribution of general water-
quality and constituent transport in relation to hydrologic conditions and contaminant sources;

2. Intensive Fixed-Site assessments characterize seasonal and short-term temporal variability of
general water quality and constituent transport and determine the occurrence and seasonal patterns
in concentrations and transport of dissolved pesticides; and

3. Synoptic studies are investigations of the geographic distribution of selected water-quality
characteristics in greater detail during specific seasons and in relation to sources.

Site choices and sampling strategies for Basic Fixed Sites and Intensive Fixed Sites are particularly
important to the success of the stream-water design for national water-quality assessment because in this
part of the study design all components are integrated by a nationally consistent strategy in all Study
Units. The focus of this report is on field procedures for collecting and processing samples from Basic
Fixed Sites and Intensive Fixed Sites.

Each Study Unit typically has three to five integrator Basic Fixed Sites and four to eight indicator
Basic Fixed Sites. Intensive Fixed Sites usually are composed of one or two Integrator Sites and one to
four Indicator Sites. Samples are collected from each site at fixed intervals and at extreme flows. The
analytical strategy for samples collected at Basic Fixed Sites is summarized in table 1; the strategy for
samples collected at Intensive Fixed Sites is the same, but with the addition of laboratory analyses of
dissolved pesticides (table 2).

Overview of Water-Column Study Design 3