ON CHANGE OF REDUCTION FACTOR OF MAXIMUM RUNOFF MODULUS WITH INCREASE OF CATCHMENT AREA
When forming river runoff, as a rule, its maximum modulus decreases (reduction) as the catchment area increases. For catchments with an area of less than 5 km2, reduction of maximum drainage and runoff modules is not expressed, which confirms the accepted assumption of equal drainage and runoff for small catchment areas. This is the first stage of the process of forming flood water runoff on channel-free slopes. At the second stage, catchments with an area of 5 to 10 km2 tend to decrease the maximum runoff modulus with an increase in catchment area. The reason for the decrease in drainage modules is a decrease in the effective catchment area as a result of a change in the snow cover area; for water flow modules - reduction of the effective catchment area and beginning of channel regulation. At the third stage, at catchments with an area of 10 to 100 km2, a decrease in the maximum water flow modulus depending on the catchment area has a stable tendency, determined by channel regulation, a decrease in the existing catchment area, and features of the increase in the catchment area along the length of the main watercourse. At the fourth stage, at catchments with an area of more than 100 km2, the reduction of the maximum module of water flow has a stable appearance and is determined by channel regulation and features of the increase in the catchment area along the length of the main watercourse. For small watercourses, the dependence of the shape coefficient of the catchment (Kf) on its area reflects the process of development of the catchment from slopes in which the width of the catchment is significantly longer, to watercourses where the width of the catchment becomes less than the length of the watercourse. In general, Kf is not sufficiently informative and does not reflect the features of the increase in catchment area along the length of the channel of the main watercourse. The main reason for using Kf in analysis and calculations is the lack of cadastral data on the increase in catchment area along the length of the main watercourse bed for all hydrologically studied rivers
Nezhikhovskii R.A. Ruslovaya set' basseina i protsess formirovaniya stoka vody [The channel network of the basin and the process of water flow formation]. Leningrad, Publ. Gidrometeoizdat, 1971. 476 p. (In Russian).
Tumanovskaya S.M. Raschet maksimal'nogo stoka vesennego polovod'ya s malykh vodosborov i sklonov na osnove krivoi reduktsii vodootdachi [Calculation of the maximum runoff of spring floods from small catchments and slopes on the basis of the water loss reduction curve] In B.B. Bogoslovskii (ed.) Issledovaniya formirovaniya rechnogo stoka i ego raschety [Studies of river runoff formation and its calculations], Leningrad, Publ. of Leningrad Polytechnic Institute, 1981, pp. 97-106. (In Russian).
Tumanovskaya S.M. Osobennosti organizatsii polevykh issledovanii na malykh vodosborakh dlya otsenki kharakteristik maksimal'nogo stoka [Features of the organization of field research on small catchments to assess the characteristics of maximum runoff]. In V.I. Babkin (ed.) Usloviya formirovaniya i metody prognoza stoka Volgi: sbornik rabot po proektu RFFI (93-05-9111) [Conditions for the formation and methods of forecasting the runoff of the Volga: Collection of papers on the RFBR project (93-05-9111)]. Saint Petersburg, Publ. of Gidrometeoizdat, 1995, pp.70-81. (In Russian).
Vinogradov A.Yu., Nikiforovskii A.A., Doganovskii D.A., Belonogova N.A., Vinogradova T.A., Markov M.L., Salminen E.O., Tyurin N.A. Novye metody raschetov maksimal'nogo stoka dlya malykh vodotokov lesnoi zony [New methods for calculating the maximum flow for small watercourses in the forest zone]. Saint Petersburg, Publ. of SPbGLTU, 2015. 481 p. (In Russian).
Abstract views: 53 PDF Downloads: 0