782 BRADT 



Bushkill Creek exhibits longitudinal zonation in chemistry and in 

 the benthic macro invertebrate community. Longitudinal zonation in 

 streams has been discussed by Minckley (1963), Odum (1971), 

 Hynes (1972), Allen (1975), and Reid and Wood (1976). Total 

 alkalinity, pH, conductivity, nitrate, chloride, total iron, and calcium 

 all increase in the downstream areas. Temperature and orthophos- 

 phate levels increase only slightly. The benthic macroinvertebrate 

 community diversity index decreases in the lower reaches of the 

 stream, and the dominant organisms also change. The stream has 

 recovered partially from the effects of rechanneling, but the extent 

 of recovery is difficult to evaluate owing to the lack of studies before 

 the rechanneling. 



Urbanization in the form of road building, manufacturing, and 

 land development has stressed the homeostatic mechanisms of 

 terrestrial ecosystems in the drainage basin with the export of 

 increased dissolved and particulate matter into streams. This stress 

 has caused increased rates of eutrophication in aquatic ecosystems 

 (Likens and Bormann, 1974). The longitudinal zonation noted in the 

 stream is evidence of the impact of increased urbanization on the 

 chemistry and biology of the lower stream reaches. If the stream is to 

 continue to support a reproducing brown trout population, the 

 impact of urbanization in the drainage basin must be minimized. 



REFERENCES 



Allen, J. D., 1975, The Distributional Ecology and Diversity of Benthic Insects 



in Cement Creek, Colorado, Ecology, 56(5): 1040-1053. 

 American Public Health Association, Inc., 1965, Standard Methods for the 



Examination of Water and Wastewater, 12th ed., American Public Health 



Association, New York. 

 Armitage, K. B., 1958, Ecology of Riffle Insects of the Fire Hole River, 



Wyoming, Ecology, 39: 571-580. 

 Beyerle, G. B., and E. L. Cooper, 1960, Growth of Brown Trout in Selected 



Pennsylvania Streams, Trans. Am. Fish. Soc, 89: 255-262. 

 Bigga, J. W., and R. B. Corey, 1969, Agricultural Drainage and Eutrophication, 



in Eutrophication: Causes. Consequences, Correctives, pp. 404-445, National 



Academy of Sciences, Washington, D. C. 

 Bradt, P. T., 1974, The Ecology of the Benthic Macroinvertebrate Fauna of the 



Bushkill Creek, Northampton County, Pa., Ph. D. Thesis, Lehigh University, 



Bethlehem, Pa. 

 Cairns, J., Jr., and K. L. Dickson, 1971, A Simple Method for the Biological 



Assessment of the Effects of Waste Discharges on Aquatic Bottom-Dwelling 



Organisms, J. Water Pollut. Control Fed., 43(5): 755-772. 

 Denoncourt, R. F., and J. Polk, 1975, A Five- Year Macroinvertebrate Study 



with Discussion of Biotic and Diversity Indices as Indicators of Water 



Quality, Codorus Creek Drainage, York County, Pennsylvania, Proc. Pa. 



Acad. Sci, 49: 113-120. 



