Non-Point-Source Impacts on Stream Nutrient Concentrations Along a Forest to Urban Gradient

We conducted statistical analyses of a 10-year record of stream nutrient and sediment concentrations for 17 streams in the greater Seattle region to determine the impact of urban non-point-source pollutants on stream water quality. These catchments are dominated by either urban (22–87%) or forest (6–73%) land cover, with no major nutrient point sources. Stream water phosphorus concentrations were moderately strongly (r2 = 0.58) correlated with catchment land-cover type, whereas nitrogen concentrations were weakly (r2 = 0.19) and nonsignificantly (at α < 0.05) correlated with land cover. The most urban streams had, on average, 95% higher total phosphorus (TP) and 122% higher soluble reactive phosphorus (SRP) and 71% higher turbidity than the most forested streams. Nitrate (NO3), ammonium (NH4), and total suspended solids (TSS) concentrations did not vary significantly with land cover. These results suggest that urbanization markedly increased stream phosphorus concentrations and modestly increased nitrogen concentrations. However, nutrient concentrations in Seattle region urban streams are significantly less than those previously reported for agricultural area streams.

[1]  I. Droppo,et al.  In‐channel surficial fine‐grained sediment laminae. Part II: Chemical characteristics and implications for contaminant transport in fluvial systems , 1994 .

[2]  S. Carpenter,et al.  NONPOINT POLLUTION OF SURFACE WATERS WITH PHOSPHORUS AND NITROGEN , 1998 .

[3]  M. Abelho,et al.  From Litterfall to Breakdown in Streams: A Review , 2001, TheScientificWorldJournal.

[4]  U. Aswathanarayana,et al.  Assessing the TMDL Approach to Water Quality Management , 2001 .

[5]  Derek B. Booth,et al.  Urbanization and the Natural Drainage System -- Impacts, Solutions, and Prognoses , 1991 .

[6]  J. Melack,et al.  Nitrogen and Sulfate Export from High Elevation Catchments of the Sierra Nevada, California , 1998 .

[7]  Awwa,et al.  Standard Methods for the examination of water and wastewater , 1999 .

[8]  R. Carignan,et al.  Influence of catchment topography on water chemistry in southeastern Québec Shield lakes , 1997 .

[9]  Hans W. Paerl,et al.  Coastal eutrophication and harmful algal blooms: Importance of atmospheric deposition and groundwater as “new” nitrogen and other nutrient sources , 1997 .

[10]  James R. Hussey,et al.  IMPACTS OF URBANIZATION ON NUTRIENT CONCENTRATIONS IN SMALL SOUTHEASTERN COASTAL STREAMS 1 , 2003 .

[11]  Michael J. Wiley,et al.  Empirical relationships between land use/cover and stream water quality in an agricultural watershed , 1988 .

[12]  D. Tufford,et al.  In‐Stream Nonpoint Source Nutrient Prediction with Land‐Use Proximity and Seasonality , 1998 .

[13]  Alletta Brenner,et al.  Review of The quality of our nation's waters : nutrients and pesticides , 2004 .

[14]  Mark A. Nearing,et al.  A Single, Continuous Function for Slope Steepness Influence on Soil Loss , 1997 .

[15]  W. Stahel,et al.  Log-normal Distributions across the Sciences: Keys and Clues , 2001 .

[16]  H. Miegroet,et al.  Soil Nitrogen Dynamics following Harvesting and Conversion of Red Alder and Douglas Fir Stands , 1992 .

[17]  Baoyuan Liu,et al.  Slope Length Effects on Soil Loss for Steep Slopes , 2000 .

[18]  George Tchobanoglous,et al.  Wastewater Engineering Treatment Disposal Reuse , 1972 .

[19]  Richard C. Lathrop,et al.  Phosphorus Loads to Surface Waters: A Simple Model to Account for Spatial Pattern of Land Use , 1996 .

[20]  R. Edmonds,et al.  Biogeochemistry of an old-growth forested watershed, Olympic National Park, Washington. Author's reply , 1996 .

[21]  R. Coats,et al.  Patterns of nitrogen transport in streams of the Lake Tahoe Basin, California‐Nevada , 2001 .

[22]  T. Williams,et al.  Patterns of nutrient loading in forested and urbanized coastal streams , 1997 .

[23]  E. Welch.  Ecological effects of wastewater , 1980 .

[24]  H. Akaike.  Statistical predictor identification , 1970 .

[25]  Kurt H. Riitters,et al.  GEOGRAPHIC TARGETING OF INCREASES IN NUTRIENT EXPORT DUE TO FUTURE URBANIZATION , 2002 .

[26]  J. Meyer,et al.  Streams in the Urban Landscape , 2001 .

[27]  R. Brian E. Shutes,et al.  The impacts of urban discharges on the hydrology and water quality of an urban watercourse , 1996 .

[28]  A Zero Degree of Freedom Total Phosphorus Model; 2. Application to Lake Sammamish, Washington , 1997 .

[29]  T. B. Thomas,et al.  Biogeociiemistry of AN Old-Growth Forested Watershed, Olympic National Park, Washington , 1995 .

[30]  G. Stuart.  DISCUSSION.: "Biogeochemistry of an Old-Growth Forested Watershed, Olympic National Park, Washington," by Robert L. Edmonds, Ted B. Thomas, and Roger D. Blew , 1996 .

[31]  D. Binkley,et al.  Influence of red alder on soil nitrogen transformations in two conifer forests of contrasting productivity , 1997 .

[32]  A. E. Greenberg,et al.  Standard methods for the examination of water and wastewater : supplement to the sixteenth edition , 1988 .

[33]  D. Booth,et al.  A Rapid Land Cover Classification Method for Use in Urban Watershed Analysis , 2003 .

[34]  M. Meybeck.  Man and river interface: multiple impacts on water and particulates chemistry illustrated in the Seine river basin , 1998, Hydrobiologia.

[35]  R. Wetzel.  Limnology: Lake and River Ecosystems , 1975 .

[36]  E. G. McPherson,et al.  Structure and Sustainability of Sacramento's Urban Forest , 1998, Arboriculture &amp; Urban Forestry.

[37]  J. Omernik.  The influence of land use on stream nutrient levels , 1976 .

[38]  R. Edmonds,et al.  TRENDS IN PRECIPITATION AND STREAM CHEMISTRY IN A PRISTINE OLD‐GROWTH FOREST WATERSHED, OLYMPIC NATIONAL PARK, WASHINGTON 1 , 1997 .

[39]  C. Goldman.  The Contribution of Alder Trees (Alnus Tenuifolia) to the Primary Productivity of Castle Lake, California , 1961 .