Bu kapsamda Biga Çayı havzası alt havzalara ayrılarak, alt havzaların morfometrik özellikleri belirlenmiş ve bu özelliklere bağlı taşkın üretme potansiyelleri incelenmiştir. Geographical Analysis 4, 194- 6. This minimum area, which Lambert 1975 termed the threshold area of surface r2moff, is a result of the interaction of local geographical factors. I n this case, the stream segments of lower order are very numerous on the hill slopes. Higher R b indicates a strong structural control on the basin, whereas, lower values indicate that the area is less affected by structural disturbances Strahler, 1964; Vittala et al. Considering the sixth-order basins, those which have developed in mountainous regions have mean surface slopes greater than their mean river-network slopes.
This paper is considered to explore some specific characteristics of very small river system, that how Sapahi river system behaving with their surface configuration. The area unoccupied by the four basins is divided in five interbasin areas coded 1, 3, 5, 7, and 9 also from down--to--upstream. The first part of this book provides detailed insight into conditions of water flows within nine river basins. However, why should it be necessary to employ this formula if all the streams have been measured in order to establish the summed-lengths ratio9 Verification of the law of summed lengths for a large number of cases proves that for sufficiently large basins the summed length of firstorder streams may be omitted, since this is the most expensive to measure. In this context, it should be normal that for the geomorphologic characterization of any geographical space we also take into account the fluvial morphometry parameters, which can be very useful in quantitative geomorphology studies. A good example of the last point is provided by the Pirscov stream, a left-side tributary of the Ialomita, for which a large difference 11.
Entering the data-base of the lines theme, one may obtain information on the law of stream numbers, average lengths and average perimeters. Traditional techniques for calculation of drainage basin characteristics area size, stream length, slope, stream order and so on are field-inspection method Zavoianu 1984 , the blue-line method Horton 1932 Horton , 1945, the contour crenulation method Strahler 1953 , Horton-Strahler ordering method Miller 1953 , slope-criterion method Smart 1978 , calculation of distances along paths extracted from topographic maps Mueller 1979. The drainage basin as a system unit. For instance, Back 1957 established an equation relating channel slope to the ratio 176 of sediment particle size and drainage area. This book examines the numerical approaches used in hydrodynamic and pollutant transport modeling.
Results showed that gullies could generally be accurately interpreted from the image, with an average relative error of gully area and gully perimeter being 11. To judge whether gullies were mapped accurately further, a standard adopting one-pixel tolerance along the mapped gully edges was proposed and proved to be practical. Depending on local conditions, the transition to a higher order may occur before the accumulation of all streams of lower orders, as is the case for the upstream from its confluence with the Brztei Fig. For greater reliability, the average of the partial ratios weighted by the lengths of the streams considered may be used in the computations. For instance, considering the fourth-order basin of the Valea Raciu upstream from its confluence with the Ialomita, the geometric progression 121 : 22 : 4 : 1 is obtained. These models span the range from highly theoretical, fine resolution, physically-based designs to lumped, black-box representations of real world phenomena. However, the values for the mean basin slope define only one curve with a slight inflection corresponding to the border area between nonconsolidated and consolidated rock Fig.
Being such an important parameter, drainage density has been studied by many researchers, who have dealt with both the definition of the concept and quantitative methods of calculation, and the relationships of causality and interdependence with the factors determining it. The value of the abscissa may be established using eqns. Other specialized Soviet work has used a ratio resembling Horton's form factor to express basin shape. Concomitant with the reduction in channel slope, valleyside slope processes carry new material downwards. For nonconsolidated rocks, whose resistance coefficient ranges from 1 to 4, there is a direct relationship between geological resistance and stream or drainage density.
The latter should be determined only after the straight line for all the other streams in the drainage basin concerned has been well established, since it depends on the 2 Fig. The data were extracted from 1 : 25 000 maps, and values were obtained for 550 representative points in basins of various orders from the first to the eighth order in the classification system adopted. The study area was divided into six sub-basins. The accuracy required in drainage-density measurements depends on the goal pursued, and is limited by the scale of the map used. The mean altitude can also be calculated as the mean of the extreme altitudes, but the results are generally not so accurate : However, this method yields good results when applied to lower-order basins with a more homogeneous relief.
Further, the tectonic tilting and moderate to coarse drainage density may possibly be responsible for quicker runoff, amplified erosion, and subsequently increased flooding around the study area. The average mean slopes, obtained by dividing the terms of the preceding series by the corresponding numbers of basins, again form a geometric series in which the average mean slopes of basins of successively hig7er orders tend to form a geometric progression in which the first term i s the average mean dope s b l of first-order basins and the ratio is the ratio rsb of successivs average mean slopes. This volume is the essential reference point for students of physical geography and related environmental disciplines, lecturers and interested individuals alike. Mass wasting often results from the combined effect of tectonic and climate processes. The depth and size of incipient water courses also depend on the physiographical conditions of the slope.
The following conclusions were drawn. When a stream has a well-developedfloodplain, the length of the valley is measured along t,he axis dividing the strip between the bases of the walls into two equal parts Fig. In case digitisation on the maps of scale 1:25 00 is done manually it is recommendable that the smallest fingertip tributaries and their basin units, evidenced and measured, be of the 2nd-order. Progress in Geography 3, 87- 109. For the Ialomita river, the sinuosity coefficient is 1.
Bu çalışmanın amacı, Biga Çayı havzasında meydana gelen uzun süreli taşkın olaylarının nedenlerinin havza ve alt havza morfometrisi bakımından araştırılmasıdır. Simultaneously, drainage basins are being coded in the data-base. It is thus obvious that the energy available for erosion and transport is directly proportional to the amount of runoff and distance of fall specific to a channel network. When the rain intensity remains at values higher than the infiltration capacity, the microdepressions become overfilled and streamlets of water start to run off which may cover large slope areas. As has been seen, the ratio of the two series gives an increasing geometric progression which represents the average lengths of streams of successive orders. For agricultural soil, infiltration depends more on the average weighted porosity of the layer over a depth of 30 cm : where pa is the porosity and m and 91 are parameters Stgnescu, 1964. Similar to the classification of the network, this system allows for the stream of a given order to directly receive lower-order tributaries without changing its order of magnitude.