CONNECTIVITY OF STREAMS AND WETLANDS TO DOWNSTREAM WATERS: AN INTEGRATED SYSTEMS FRAMEWORK.

Interest in connectivity has increased in the aquatic sciences, partly because of its relevance to the Clean Water Act. This paper has two objectives: (1) provide a framework to understand hydrological, chemical, and biological connectivity, focusing on how headwater streams and wetlands connect to and contribute to rivers; and (2) review methods to quantify hydrological and chemical connectivity. Streams and wetlands affect river structure and function by altering material and biological fluxes to the river; this depends on two factors: (1) functions within streams and wetlands that affect material fluxes; and (2) connectivity (or isolation) from streams and wetlands to rivers that allows (or prevents) material transport between systems.

Validation of rapid assessment methods to determine streamflow duration classes in the Pacific Northwest, USA.

United States Supreme Court rulings have created uncertainty regarding U.S. Clean Water Act (CWA) authority over certain waters, and established new data and analytical requirements for determining CWA jurisdiction.

Spatial and temporal patterns of dissolved nitrogen and phosphorus in surface waters of a multi-land use basin.

Research on relationships between dissolved nutrients and land-use at the watershed scale is a high priority for protecting surface water quality. We measured dissolved nitrogen (DN) and ortho-phosphorus (P) along 130 km of the Calapooia River (Oregon, USA) and 44 of its sub-basins for 3 years to test for associations with land-use. Nutrient concentrations were analyzed for spatial and seasonal patterns and for relationships with land-use and stream discharge.

Surface water and groundwater nitrogen dynamics in a well drained riparian forest within a poorly drained agricultural landscape.

The effectiveness of riparian zones in mitigating nutrient in ground and surface water depends on the climate, management, and hydrogeomorphology of a site. The purpose of this study was to determine the efficacy of a well drained, mixed-deciduous riparian forest to buffer a river from N originating from a poorly drained grass seed cropping system. The study site was adjacent to the Calapooia River in the Willamette Valley, Oregon.

Nitrate-nitrogen, land use/land cover, and soil drainage associations at multiple spatial scales.

Managing non-point-source pollution of water requires knowledge of land use/land cover (LULC) influences at altering watershed scales. To gain improved understanding of relationships among LULC, soil drainage, and dissolved nitrate-N dynamics within the Calapooia River Basin in western Oregon, we selected 44 watersheds ranging in size between 3 and 33 km(2) for monthly synoptic sampling of surface water quality between October 2003 and September 2004. Seasonal associations were examined between dissolved nitrate-N and proportion of woody vegetation or poorly drained soils at differing scales (10, 20, 30, 60, 90, 150, 300 m, and entire watershed), which we defined as influence zones (IZs), surrounding stream networks.

Diuron occurrence and distribution in soil and surface and ground water associated with grass seed production.

Little is known about the occurrence and distribution of the herbicide diuron [3-(3,4-dichlorophenyl)-1,1-dimethyl urea] in soil, ground water, and surface water in areas affected by grass-seed production. A field study was designed to investigate the occurrence and distribution of diuron and its transformation products at a poorly drained field site located along an intermittent tributary of Lake Creek in the southern Willamette Valley of Oregon. The experimental sites consisted of a field under commercial grass seed production with a cultivated riparian zone and a second site that was part of the same grass seed field but with a noncultivated riparian zone.

Nitrate removal effectiveness of a riparian buffer along a small agricultural stream in western Oregon.

The Willamette Valley of Oregon has extensive areas of poorly drained, commercial grass seed lands. Little is know about the ability of riparian areas in these settings to reduce nitrate in water draining from grass seed fields. We established two study sites with similar soils and hydrology but contrasting riparian vegetation along an intermittent stream that drains perennial ryegrass (Lolium perenne L.

Floodplain Formation and Cottonwood Colonization Patterns on the Willamette River, Oregon, USA.

/ Using a series of aerial photographs taken between 1936 and 1996, we trace coevolution of floodplain and riparian forest on the Willamette River. Within-channel barforms appear to be the predominant incipient floodplain landform and habitat for primary succession. Interlinked development of bar(s) and erosion of near banks, filling of channels, and establishment and growth of cottonwoods and willows results in coalescence with older floodplain.

Modelling episodic acidification of surface waters: the state of science.

Field studies of chemical changes in surface waters associated with rainfall and snowmelt events have provided evidence of episodic acidification of lakes and streams in Europe and North America. Modelling these chemical changes is particularly challenging because of the variability associated with hydrological transport and chemical transformation processes in catchments. This paper provides a review of mathematical models that have been applied to the problem of episodic acidification.

Comparison of episodic acidification in Canada, Europe and the United States.

Episodic acidification is practically a ubiquitous process in streams and drainage lakes in Canada, Europe and the United States. Depressions of pH are often smaller in systems with low pre-episode pH levels. Studies on European surface waters have reported episodes most frequently with minimum pH levels below 4.