drainage density formula

Drainage density is the total length of all the streams and rivers in a drainage basin divided by the total area of the drainage basin. endobj 9 0 obj �ŭ P�_�Z�\ۤP�D��ۭ��!�vt:� A�� <> As nouns the difference between discharge and drainage is that discharge is (symptom) (uncountable ) pus or exudate (other than blood) from a wound or orifice, usually due to infection or pathology while drainage is a natural or artificial removal of surface and sub-surface water from a given area. ȳ�Y.��-�t.�|��]�ǩ�&0��;5��5��:��I��&G��CŃM_��䟠��^.xg>�O��\!F�} Ye *;|��X�G�m**�t��~�i�� 6X�i��@� n��8mhQ��tk�LA�ՠ5�ᴊ�|y�e��i��i��b^m͟��w�{��ߘ��5��S��(ˢWt��b��qH�?NY`j:H8�M��$��!�5A�]M=s��LgKi��U��\ƪC�m�T��2VɅ�>��؜��8��|��J��*֧*��,9۷n5@�1t�c�J��c޶��5��S�zx��? The shear strength of soil depends on the effective stress, the drainage conditions, the density of the particles, the rate of strain, and the direction of the strain. <> 21 0 obj v = cross-sectional mean velocity (ft/s, m/s) k n = 1.486 for English units and k n = 1.0 for SI units < Step 3. @T��r̡��!�3n��O{��}6��0�:�ͳ��k0!��sv`�i�Ő�!��3�Kn��P��eJ��dk�%��;$X�w��;ǂԃ I�q�V�� w>��ӝA�3]5�C3��|:�s�/�'�̲X75#��}J�U�!�|`��l)>ބ�;4[�X�m+Vz*��fR�M)O��4�uL圸t�(Qx�� CE322 Basic Hydrology Horton's Laws - Example Jorge A. Ramirez . Since water has a density … As mentioned above, we know that drainage density is equal to the total length of all channels within the basin divided by the total area of the basin: Drainage Density = total length channels (m) = m -1 endstream <> endobj Drainage densities in semi-arid to humid landscapes range from 2 to 12 km km-2, primarily reflecting variations in precipitation (Abrahams 1972) and lithology (Grant 1997) and see Eccker 1984 and Bloomfield et al. My study area is subarnarekha river basin and i want to calculate drainage density for each grid (2km*2km). endobj Runoff Equation In most cases, storm water runoff can be calculated using the Rational Method. <> endobj Freebase (0.00 / 0 votes)Rate this definition: Drainage density. Soil scientists also incorporate the density of water (WD) into θv as: θv = θg * (BD / WD) (Equation 3) However, the value of WD is close to 1 and is typically ignored when calculating θv. 10 0 obj For example, everything else being equal, highly erodible and impermeable rocks tend to have higher drain-age density than areas dominated by resistant or permeable rocks. One drainage basin attribute of particular importance for this research is drainage density. 5 0 obj 19 0 obj <> endobj endobj ��7]W��-<2}�Ս]+V��܁��-�t�u��-��`g.�:U �ݺ�V٘O�I��:�n��~� �+B>p�d��m��t�9;e�s��P6ؕ(��D�b�TS��?��B��e��HaYg��'�� g�e�Y�G��فZ�V��'��h�\'$�ڱ�}0Fj�%J0�ʀ��KoB��P�7�[T�3��l��s�á1�ȁ�Y>��$�T�K{�k~( �&�q�C�h �W](�&�Q�p�^X��.$�D�)��C1�ܻ��_�r��R��o��ʇ��U�3�W�;�ɠV�(��'�lH�6��1ę �9(c��~6��%U �C��k��l�yi�bp�W�Ipbd_a�b� mc�I}P�)�ϵ�u ��l��9>B͎t��3�8��*$��$�G�ȥI��{��toL��2��X��tC��T��=�UՎz��AEkr˚��"�� g�� X�8^Q(��}��m�I�QSАC��}Zh�j�[�^��wD�H�� b�p��s�B"3��\10&�7�F�̌+ -��7��6�UT2��>�� 4̀9��?2�� z��! 6. The destructive power of flowing water, as stated in Section 3.2.2, increases exponentially as its velocity increases. 24 0 obj An object is weighed in air and found to have mass m = 500 g. It is then submerged in water and found to have apparent mass m 2 = 420 g. It is clear that it has displaced m – m 2 = 80 g of water. 15 0 obj endobj The value signifies the storage capacity of a basin and determines the relationship between drainage density and physiographic development of the basin. The design rainfall intensity in inches/hour is one of the parameters needed to calculate peak runoff rate for design of a variety of stormwater management structures, such as storm sewers, stormwater inlets, and stormwater detention structures, using the Rational Method. endobj Obtain estimates of the Bifurcation Ratio, R B, the Length Ratio, R L, and the Area Ratio, R A, using the data tabulated below.Also, for the same data, a) determine the area of the basin, b) the total length of streams, c) the drainage density, D d, and d) the average length of overland flow, L o. Below is a flow diagram of the drainage basin system:All rivers receive a water supply and the area of land this comes from is known as a drainage basin. x��ZI�,��ϯ��[�V��P��o�t:i1?颿�Xr��CuVfDd�k=s�鏷�&3�>F��7-��6��_ҿ��v�|��v�1�ϟ�o>`�8}��ɾ{9�w�.��/'x7�-ȻH�邯f��J��Ƨ�S|7��>�^X/�@$}�pqyx��T�lcz˄�N��U(��s��Ϸ��۷��x��h�ىB�&+yY�:�.=�(��N��e�^PB��B<=܈̕5��9��!��6f��~g�jm�!U{a�wي��VyiY��|Q��_bw��''Ҫ�O[�JR�%B84�YM`&%��{ ٨��:`��[��1v��;E��D#Cv��zm��[��DQW�� Z5�t:�⸕��[��^� �7jE endobj 29 0 obj �oB�k/��,^��"�ybͳ��@�~��o�>]��EâA}��)U8�T QJ)��Wq��9��GR^uT>�*�B�4*�E�d ��C+d,4/��e`]�z��l��@�l[� <> Rf = Form factor, A = watershed area, km 2. Form factor. Volume of water in pipe - calculation example Let's see how to use the pipe volume calculator correctly. A mathematical model for this system, which was developed by C. E. Jacob, can be expressed in the equation T= WD~2/8h0t in which T is transmissibility, W is recharge, D … 16 0 obj 30 0 obj %PDF-1.4 ��(kB"�)��le=�8�:��Z\Y��"�F�.��k��Ē��$~��K��R�8��p��Is�9�y�+� K�Q��Ɏ3�,t{s�E�~T³��m� �QjWno��uBR��;1ה��$9%,��ֻ+�`�4�2�Z �k� �BG��+�="�г�`Ɣ ��an�\��C��x�U��H��Zו� J�T�\�="O�¬�5� ��6�� endobj T{PvSJ��ڎ�GY�0C ��`�e��D�Cդ��u)��2�0L��̛|��k��f["��XF ��!b�6�R�ڲt�1ӕ�zZ֏��ek�K7��;�Ҧ��OI�p�@�AT�w��z�M�Je�5��6��};�eƳF�[�n��~-��7��_�T�j 6�jpƋD �m[,��"�+V�j�!�9��bHD�k��S��՜9�K��HW��?��>b�Yc��!x��q��%,cU�⌳K�O1�b��U�&��rQH�. 28 0 obj endobj Higher drainage density increase time to peak and peak discharge. 8 0 obj Stream order (Shape file) 2. The drainage density exertes on ﬂood peaks signiﬁcant controls which can be broadly divided between direct and indirect effects (Merz and Bloschl¨ , 2008; Bloschl¨ , 2008). /zҠ�t��ʾ�F]��e�"|>?�]�M�)��,2)G|KA �ڗY��r�! 22 0 obj For drainage areas greater than 200 acres, other methods can be used, or the drainage area can be divided into zones less than 200 acres. endobj V��3��( ��z`��[�RN�F�0+�UƵa�0(�!Z� n|ZJ)T��^�dF9w�l�Q�bb��`��VOP��^:�J�&� u�X�^6��FJ��c@w ��&� ��uR��#>/��t drainage density = stream length / basin area. Formula for drainage density = length of the streams within 1 km2 unit area. Drainage density—the length of channels per unit area—varies accord-ing to several environmental factors. Data sets required: 1. It is a measure of how well or how poorly a watershed is drained by stream channels. 7 0 obj Therefore, water must not be allowed to develop sufficient volume or velocity so as to cause excessive wear along ditches, below culverts, or along exposed running surfa… <> <> endobj <> endobj ;�Z�m�P|yJ�0+~�.N� �s��SUl�'2:� A@P�^%�[�q�2Ōl+ L b = watershed length, km. 18 0 obj <> endobj endobj This article describes how to obtain a value for design rainfall intensity. Drainage density. In summary, Equation 1 is used to calculate gravimetric soil water content and Equation 2 is used to calculate volumetric soil water content. endobj Step 2. 13 0 obj Road drainage design has as its basic objective the reduction and/or elimination of energy generated by flowing water. <> Drainage density, surface-water discharge, and ground-water movement are shown to be parts of a single physical system. <> <> A … A = watershed area, km 2. Roads will affect the natural surface and subsurface drainage pattern of a watershed or individual hillslope. <> This method can be used for all drainage areas less than 200 acres. 25 0 obj <> <> %äüöß Subwatersheds belonging to C4 and C5 (Table 3 ; Figure 3(a) ) having high values of are at a greater risk of being eroded by … Drainage density is calculating using the following formula: Drainage Density = total length channels (m) = m-1 2 basin area (m) The procedure outlined below provides the … ѹ�M��Mh��/peL߈A�._��(�5�G(r��@� <> [ 27 0 R] Assume the length of the perforated interval h p.. endobj 6 0 obj For undrained, constant volume shearing, the Tresca theory may be used to predict the shear strength, but for drained conditions, the Mohr–Coulomb theory may be used. This concept reaches into many fields of engineering. <> The book describes the drainage basin as a system unit resulting from the interaction between runoff and topography - a lengthy process of evolution that occurs according to well-defined laws. endobj $.' ?�o��NBoG�3�7�>ҹ� ��@�&=��0R5^n Rb=Nu/ Nu+1; where, Nu=Total number of stream segment of order‘u’,Nu+1=Number of segment of next higher order. Hydrology: Horton's Law & Drainage Density Example - YouTube �� JFIF ` ` �� ZExif MM * J Q Q �Q � �� C So, respectively: liquid mass = volume * liquid density. <> <> ��Y%��U2_ endobj In determining the peak runoff of watersheds, the drainage area is needed. E�l�O��P9w��=n"��X��-`m�� Drainage density is a fundamental landscape metric describing the extent of the fluvial network. <> Calculating drainage density or calculating storm drainage for secondary roads begins with the drainage area. 12 0 obj drainage pattern (Nag, 1998). Calculate the dimensionless perforated length ɛ = h p /h.. For a given dimensionless radius r De and knowing GOC, WOC, and fluids density, the specific steps of the proposed methodology are summarized below:. A drainage basin is a land surface region drained by … =�Z��]�Z[/�[��_��[�n�F{S�wl��u1H�r�N��h2��=]�@�4Ώ��I{�hx��k�X��]��e�Q^F(�t��cE}��s�orsYz��f�R�h��r�@�X ��2��0刚��v�f��s�kFG�q�#�Ew�s��)g�e��%�u,w ڋ,�9�-�(�YN�َ��xl�5'7��{��I��=��MUu�訦�յ��fv�f?��{�lo ",#(7),01444'9=82. endobj Manning's equation can be used to calculate cross-sectional average velocity flow in open channels. As a verb discharge is to accomplish or complete, as an obligation. 11 0 obj <> endobj Drainage density D was defined by Horton as D ≡ L/A, where L is the total length of stream thalwegs in an area of size A. endobj 26 0 obj stream 17 0 obj endobj A = Drainage area, acre Note that our calculation allows you to use a variety of units. 27 0 obj 23 0 obj I have generated grid using fishnet tool in Arc GIS over my study area. 14 0 obj Among the most signiﬁcant direct effects there is the con-trol associated with the length of the stream network and stream Drainage density, defined as channel length per unit watershed area (km km-2), reveals the amount of channels in a watershed. <> The Rational method runoff coefficient (c) is a function of the soil type and drainage basin slope. D = drainage density; Lu = total stream length of all orders, km and. Areal Drainage Density (Dd) (Horton, 1932) Drainage density (Dd) shows the landscape dissection, runoff potential, infiltration capacity of the land, climatic conditions and vegetation cover of the basin. <> P = Density m = Weight or Mass in Air m 2 = Weight in Water. The drainage basin - as stated earlier - is an example of an open system, and many of the terms above are central to it. The mass of the liquid is taken from the transformed density formula. Drainage density, D d, is defined as the total length of channels per unit area [], and it describes the drainage spacing and distribution in a catchment [].It can be said that the ratio that defines drainage density also represents the quantity of rivers in the catchment needed to drain the basin []. Drainage density (Dd), defined as the total length of channels per unit area, is a fundamental property of natural terrain that reflects local climate, relief, geology, and other factors. 20 0 obj v = (k n / n) R h 2/3 S 1/2 (1) where. A drainage network is a system of interconnected stream channels found in a drainage basin. endobj <> In the field of hydrology, calculating drainage area is a critical element in many practical applications. Step 1. Drainage density is strongly correlated with the valley or channel head source area: that is the basin size where the transition from convex or straight hillslopes to concave valleys, or to well‐defined channels occurs [Montgomery and Dietrich, 1989; Moglen et al., 1998]. 2 0 obj 2011. <> endobj Runoff coefficient ( c ) is a critical element in many practical applications and Equation 2 is used to volumetric... Density formula power of flowing water movement are shown to be parts of a basin i... 'S see how to obtain a value for design rainfall intensity so, respectively: liquid =! 2Km * 2km ) density and physiographic development of the soil type and drainage.... Or individual hillslope a variety of units liquid density a … Freebase ( 0.00 / 0 votes ) this... 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Used for all drainage areas less than 200 acres poorly a watershed is drained by stream channels found in drainage! Channels found in a drainage network is a function of the perforated interval h p /h = volume * density! Determines the relationship between drainage density for each grid ( 2km * 2km ) density … in the of... N / n ) R h 2/3 S 1/2 ( 1 ) where or mass in Air m =! Or calculating storm drainage for secondary roads begins with the drainage area is needed ɛ = p.