Responses of Physical, Chemical, and Biological Indicators of Water Quality to a Gradient of Agricultural Land Use in the Yakima River Basin, Washington

Abstract

Abstract. The condition of25 stream sites in the Yakima River Basin, Washington, were assessed by the V.S. Geological Survey's National Water-Quality Assessment Program. Multimetric condition indices were developed and used to rank sites on the basis of physical, chemical, and biological characteristics. These indices showed that sites in the Cascades and Eastern Cascades ecoregions were largely unimpaired. In contrast, all but two sites in the Columbia Basin ecoregion were impaired, some severely. Agriculture (nutrients and pesticides) was the primary factor associated with impairment and all impaired sites were characterized by multiple indicators of impairment. All indices of biological condition (fish, invertebrates, and algae) declined as agricultural intensity increased. The response exhibited by invertebrates and algae suggested a threshold response with conditions declining precipitously at relatively low levels of agricultural intensity and little response at moderate to high levels of agricultural intensity. This pattern of response suggests that the success of mitigation will vary depending upon where on the response curve the mitigation is undertaken. Because the form ofthe community condition response is critical to effective water-quality management, the National Water-Quality Assessment Program is conducting studies to examine the response ofbiota to gradients ofland-use intensity and the relevance ofthese responses to water-quality management. These land-use gradient pilot studies will be conducted in several urban areas starting in 1999.

Influence of land use/land cover on the water chemistry of Wular Lake in Kashmir Himalaya (India)

“…Inorganic nitrogen in freshwaters occurs in three different forms, Over all classification accuracy = 91.45% namely ammonia, nitrates and nitrites. Agricultural as well as horticultural land practices in the immediate catchment has a direct effect on the nitrogen and phosphorus content in the water body whose loading may lead to nutrient enrichment and the deterioration of the water quality (Harding et al 1999;Cuffney et al 2000). Higher concentration of these nitrogenous forms is attributed to the use of fertilizers in and around the lakes and the addition of Parameters: 1 = water temperature; 2 = pH; 3 = dissolved oxygen; 4 = chloride; 5 = free carbon dioxide; 6 = total alkalinity; 7 = ammoniacal nitrogen; 8 = nitrate nitrogen; 9 = orthophosphate; 10 = total phosphate; 11 = agricultural land; 12 = alpine grassland; 13 = built up; 14 = dense forest; 15 = forest plantation; 16 = horticultural land; 17 = snow-covered/glacial area; 18 = sparse forest; 19 = wasteland; 20 = water bodies and 21 = wetland.…”

“…On the basis of annual mean levels of ammoniacal nitrogen, site VI ranked the highest, followed by sites III, I, V, IV and II in decreasing order. Site VI lying on the Wular periphery catchment has the maximum agricultural (r = 0.580) as well as horticultural land (r = 0.919), depicting collinear relationship of ammoniacal nitrogen with the aforesaid parameters (Harding et al 1999;Cuffney et al 2000). The concentration and rate of supply of nitrate nitrogen are intimately connected with the land use practices of the surrounding watershed (Horne and Goldman 1994).…”

Improving the quantification of land cover pressure on stream ecological status at the riparian scale using High Spatial Resolution Imagery

“…C2 and C3 are considered as the two categories causing the main alteration of stream ecological status according to large scale statistical analyses (Allan, 2004). Agricultural practices on land adjacent to streams can lead to soil erosion and subsequent runoff of fine sediments, nutrients, and pesticides (e.g., Cuffney et al, 2000;Schulz and Liess, 1999). Urbanization leads to enhanced runoff, channel erosion, and reduced water quality due to inputs of metals, oils, and road salts (e.g., Booth and Jackson, 1997;Hammer, 1972;Paul and Meyer, 2001).…”

Large‐scale relationships between basin and riparian land cover and the ecological status of European rivers

“…Various studies have demonstrated negative relationships between biological indices and the percentage of agricultural land in the catchment or gradients of agricultural intensity (Roth, Allan & Erickson, 1996;Walser & Bart, 1999;Cuffney et al, 2000). These impacts are dependent on the different categories of production: many authors designate intensive agriculture as a cause of degradation in stream habitats (Allan & Johnson, 1997;Allan, 2004).…”