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which enter streams ann rese~voirs, ao- proximately 50 percent comes from agri- cultural areas and sa percent comes from urban and const~uction areas, with the major portion coming from construc- tion areas. Th~ kinetic en~rgy of fal- ling raindrops is the agent primarily responsibl~ for erosion. Kinetic ener- gy of raindrops for a given storm is more than 200 times that of th~ runoff. Rainfall provides the energy necessary for detachment while th~ runoff pro- vides the carrier necessary to carry th~ detached particles away. The am- ount of gross erosion occurring depends on the eroding power of the r~infall and the erodibility of the soil. The Universal Lozs Equation gives erosion as a function of rainfall en~rgy and quantity, soil erodibility, slope and length, cover, and manage~ent practice. BARKDOLL, M.P. et al. 1977: -Some effects of dustfa11 on urban storm water ouali- tyw. J. W~ter pollution Control - Fea- eration. Vol.49(9): pl976-1984. Key words: water pollution: urban ru- noff: air pollution eff~cts; water pollution sources; storm runoff; heavy metals; nutrients; ch~mica1 ox- ygen demand; miscellaneous chemicals: erosion. Runoff from 47 storms in a small urban watershed was analysed for 16 water contaminants. Dustfall was also col- lected and ana1ysed. There were two distinct but overlapping groups o( con- taminants found in the storm water quality analysis. Minerals and solids have r~latively constant concentrations (rom storm to storm, wh~reas, heavy me- tals, nutrients and COD had decreasing concentrations with increasing storm water discharge. Further COD, Hg, Cl, Pb, 5i02, P04 are primarily due to dustfall. The relative influence of dustfall for other constituents will have to be verified by further study. Pervious area in urban watersheds should not he disregarded in determin- ing pollutant yields. ~odels using only street surface contaminants will yield conservative results. Removal was found to be a function of storm ru- noff volume and only mildly affected by runoff rates. Certain pollutants such as 5.5., Ca, Mg, 504, and CaC03 are available in extremely large quanti- ties. These constituents probably arise from the erosion of disturbed land areas. BARNA.RD, J.R. and CROrEY, T.E. 1974: -Physical and economic aspects associated with runoff from urban growth: a methodological approach-. In, Proceedings National Symposium on urban rainfall and runoff and sediment control, University of Kentucky, lex- ington, Ky.: p2l9-228. Key words: mathematical streamflow~ techniques; charge. Ilodel studies: models; urban runo{f~ storm runoff: analytical flood routing: flood di5- Urban growth often impinges upon local watersheds resulting in alteration of ~ the frequency and magnitude of flooding along small creeks ann low areas. Urban development gener~lly takes place within the context of government~l in- tervention through land use zoning and planning with the explicit purpose being to protect property rights. In spite of land use regulation. urban growth frequently produces negative ex- ternalities in the form of increased frequency and magnitude of flood ha- zard. This paper presented the metho- dology for examining the physical and economic aspects of urban growth in a lOcal watershed. Specifically, the Stanford Watershed Hydrologic Model was further d~velop~d for statistically determining the impact of urbanisation upon flooding frequency and magnitude. The results from the hydrologic model were linked to an economic model to de- te~mine the extent that n~gative exter- nalities impinge upon property ~s a re- sult of urbanisation and change in fre- quency and magnitude of flooding. An analysis of the property market is cen- tral to the issue of determining the effect of the changes in flooding ha- zard on property values and the extent of negative externalities upon property owners and possible income distribution effects. . . BARNES. R.C. tices tion p233. 1969: -Erosion adapted for urban abatement-. A5AE prac- pollu- No. 69: control use and Paper Key words: abatement: erosion control~ pollution erosion; flood control. . Changes in land use brought about by rapidly expanding urban centres are causing serious erosion and sediment pollution problems. This is focusing attention on the n~ed for overall plan- ning for best land use for all segments of our society; for adequate zoning to implement orderly development; for trained staff to administer, guid~, ~nd supervise developm~nts, and for quide- lines, standards and soecifications for use by those who r~quire them. Th~ basic principles for erosion control, orderly removal of excess runoff, con- trol of flooding, and reduction of sed- iment damage are known and have been used for other land uses for years, and can be modified for urban use. Any practice which uses these principles will also reduce pollution below the C1evelopment. < BARRE, N.LA. et al. 1973: nation of snow-. Vol.7(B), p1215-121B. - lead Water contami- Research, Key words: snowmelt. oil wastes; lead: , Snow from disposal sites and along roads contained considerable Pb due to the combustion of leaded gasolines by automobiles. In soite of Pb concentra- tions up to 4,330 'ppm in the sample sediment, the highest concentration in the filtrates W3S 0.21 opm with an average of 0.e4 ppm. Dumping snow away from watercourses instead of directly into them significantly reduces Pb con- tamination in the waters from this .