This will calculate the average slope for each given area. potential watershed storage (S) = 0 = 0. inch . Lag is a function of the flow length of the watershed, average land slope of the watershed, and the potential maximum retention of rainfall on the watershed. Haan et al. dom_i.query(this).attr("title",imgAlt); The direction the plane faces is the aspect for the processing cell. 2. I am trying to replicate a procedure that the USGS Streamstats performs on points delineated along a stream network. The average annual precipitation represents the amount of water available for transport in a watershed. The average slope of a watershed influences radically the value of the time of concentration and, directly, the runoff generated by a rainfall. Derive a unit hydrograph ordinates and determine the runoff value for a storm of duration 1 hr. use the SCS dimensionless unit hydrograph. if(imgTitle != ''){ No valley or reservoir routing is required. var count = 1; Watershed slope is not to be confused with the slope of the flow path. stream   EFH2 User's Manual (4.6 mb. For degrees, the range of slope values is 0 to 90. "none" : dom_i.query(this).css("float").trim(); He justified that the small watersheds are dominated by overland flow rather than channel flow. This means that the average downhill slope of 24th St as water drains along it towards Waller Creek is a little more than 3%. �A$ф���lkE*y]8�A;;R�R���_-5Mk(��:gqW� ^��Z��(G�[!����,r���IU]���c�Kar�w/�lrp,�r��;��D/&>]��ɋ��t�9ƚ�=F���C^�S��-�>�CA�S�)��Y�Hr������9|�ɞ�+j� ���7�孴��n���Et�;�w�� >���N������0�G�>�`�,S�QRt�&"���%AA��]� 6 0 obj Physiographic Characteristics Slope: It controls the rainfall distribution and movement, land utilization and watershed behavior. Watershed Slope field. Thanks! dom.query(this).attr("alt") : dom.query(this).attr("title").trim(); I am trying to replicate a procedure that the USGS Streamstats performs on points delineated along a stream network. Estimate Average Slope If you are missing any of the tools mentioned below, contact your GIS Specialist. Viewed 781 times 1. var imgMarginBottom = dom_i.query(this).css("margin-bottom") == undefined ? '' var imgAlt = dom_i.query(this).attr("alt") == undefined ? '' dom.query(this).attr("title",title); Riffles are found entering and exiting meanders and control the streambed elevation. imgMarginTop = imgMarginTop.replace("px",""); Curve numbers (CN) are used to represent watershed characteristics that … AVGSLOPE Watershed Slope Average watershed slope (percent) 4.24% 11 ELEVSTD Topographic Roughness Elevation Standard Deviation 48.2 ft 12 COS01 Crops (2011) on slopes Percent of watershed with agriculture (crops) on slopes greater than or equal to 3% 3.94% 13 LCC11 Landscape Change 2006-2011 Percent of watershed that changed land cover from 2006 -2011 using the binary change mask … } %�쏢 time of concentration: channel length: watershed area: linear profile slope: References - Books: Martin Wanielista, Robert Kersten and Ron Eaglin. Determining the average slope of a hill using a topographic map is fairly simple. The average altitude of a watershed is often used in the evaluation of certain hydro-meteorological parameters and can be calculated with relation 2.2. If the average land slope on a watershed differs from this, multiply the value from Table 1 by the following factor: Average land slope Topographic factor (T) 0.5 percent: 0.50: 1 percent: �ظ:|�U�!�`�z��c�,�e���#CUӾ�Ҡ�vƍ dom_i.query(this).css("float","none"); //]]>, Environmental Markets & Conservation Finance, MLRA Soil Survey Regional Offices Directory, Enter Keyword, Phrase, or Text to search the site. Other Units: Change Equation Select to solve for a different unknown dom_i.query(this).after("

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"); var title = dom.query(this).attr("title") == undefined ? When the bubble on a level is about 1/4 of the way past the line it is about a 1/4″ slope. – Average watershed slope is an average of individual land slope measurements. b) The average altitude of a watershed - can be deduced directly from the hypsographical curve or from reading the topographical map. Slope Calculation from Contour Lines in a Topographic Map. Watershed length is between 200 and 26,000 feet. endobj Watershed average slope offers information about the watershed topography. Watershed Subbasin Maps This web page provides access to five pre-built map series for each of Montana’s subbasins (8-digit HUC level). imgMarginBottom = imgMarginBottom.replace("px",""); Step 2. For a drainage area of Area= 38 km, Stream length L = 12 km, average watershed slope Y = 3% and CN = 77. /*dom.query(document).ready(function(){ (3) three categories of average watershed slopes. ���u�ɠ&��b�T�/A�(Ee�[iu�5R�����b))JQ��D�����+�H Precipitation, ownership, slope, land cover, and hydrography maps are provided in Adobe PDF format. x��W[OT1N�x9�MA�� ��詝���hL�/�M| �0b�����Yζ�sv1b���N��\��f�=aJ2���p0m^�zv��9i0F�c��t��R�1�~JYr�{�|k>m����;E;-�M��ڬ�9����hv.�Vg�q���P��*( �Qi �8u`���R�����%_�S�f�� ��ֱ��F1`-` N*���M��*Z� �{"H�"� т���$:_K��MTP��O��[S�muǃ�:�*t�uП'(B�1�SE�D��L��_b��,�^=�M�P�דT`�3��� Watershed lag time equation calculator solving for average watershed slope given watershed lag time, watershed hydraulic length and potential watershed storage use the SCS dimensionless unit hydrograph. Lag is a function of the flow length of the watershed, average land slope of the watershed, and the potential maximum retention of rainfall on the watershed. If the average land slope on a watershed differs from this, multiply the value from Table 1 by the following factor: Average land slope Topographic factor (T) 0.5 percent: 0.50: 1 percent: 0.65: 2 percent: 0.72: 3 percent: 0.78: Therefore, the objective of this study was to evaluate the use of the standard NRCS-CN, the slope-adjusted CN equation, and GIS to develop a database con-taining all the information of the study watershed for direct runoff depth estimation in a watershed with steep slopes. �vα�(������_7��E=����}�K_◿�~O�e�g��a�B�'Sy��R��t|����ۻI�o�7TՔ�endstream var dom_i = {}; How To: Calculate the average slope of an area using contour lines Summary. The same can be done for Slope Length as well. <> It is a relatively small watershed (~33 sq. The watershed slope, or average watershed land slope, is used in the lag equation to estimate the watershed Tc. Slope measurements should be taken through a channel reach that is a minimum of 20 channel widths in length or for a distance equal to two meander wavelengths. The curve number, CN, is an empirical value, which establishes a relationship between rainfall and runoff based upon characteristics of the drainage area. Peak discharges range from 5 to 2,000 cubic feet per second (cfs), drainage areas range from 5 to 2,000 acres, and 24-hour rainfall depths range from 1 to 12 inches. Watershed length is between 200 and 26,000 feet. if(imgMarginBottom.indexOf("px") > 0){ })*/ Dry fit PVC/ABS components first to ensure there is enough space to properly slope the entire pipe dom.query('img').each(function(){ A watershed is an area of land that drains all the streams and rainfall to a common outlet such as the outflow of a reservoir, mouth of a bay, or any point along a stream channel. S = average slope of the channel reach, m/m. F�Y�5?Q�Ān�!�����S��X�R+�ݶ��6��LU�ѹ�D��� 5(−0.0316) or, Zenith = … 903 Watershed Slope field. The water depth is relatively shallow and the slope is steeper than the average slope of the channel. if(imgAlt != 'Broken Link' && imgAlt != '' && imgAlt != 'offsite link image'){ Determining Average Slope For Small Watersheds Topics: 1. The authors investigate the effect of digital elevation model (DEM) grid size and source on the average watershed slope. Lloyd-Davies method if you are English, is probably the oldest Values in Table 1 are peak rates of runoff to be expected from watersheds with an average land slope of 8 percent. The average annual precipitation represents the amount of water available for transport in a watershed. 17 0 obj �2���X��|��RZ�T��|%������DY(��u���!�*C���%+cg��g�%u*�f } Land-surface slope, land cover, and land use have similar influences on watershed characteristics as those identified for the unsaturated zone. Slope is the measure of steepness or the degree of inclination of a feature relative to the horizontal plane. EFH2 User's Manual (link to pdf version from NRCS eDirectives website), NRCS Home | USDA.gov | Site Map | Civil Rights | FOIA | Plain Writing | Accessibility Statement, Policy and Links| Non-Discrimination Statement | Information Quality | USA.gov | WhiteHouse.gov Rational Method The Rational Method, a.k.a. dom_i.query(this).addClass('img_'+count); Watershed slope is not to be confused with the slope of the flow path. S = average watershed slope C = rational method coefficient [Originally developed for use on airfields but frequently used for urban watersheds] BEE 473 Watershed Engineering Fall 2004 B. Calculate a curve number, CN, for the drainage area. : dom_i.query(this).css("margin-bottom").trim(); Begin by Opening a MapBook Project in ArcMap. Lag is the delay between the time runoff from a rainfall event over a watershed begins until runoff reaches its maximum peak. The average annual precipitation represents the amount of water available for transport in a watershed. Slope is the rate of maximum change in z-value from each cell. dom_i.query(this).css("margin","0"); count = count+1; : dom_i.query(this).attr("alt").trim(); Series of methods have been developed to estimate the average slope of the watershed. The quantity of water thus stored by the banks temporarily is known as bank storage. This program has restricted applications. After scouting, a route is flagged and waits approval by DEP. We show that total aquatic carbon emissions covary nonlinearly with the average slope of the watershed, such that maximal emissions occur both in the flattest and steepest landscapes. //��B@�����xi�{�Ӭ�j�v�]n29�3â�1�C�ƞ�S���=7+m�A+Qj�(�-����9�9kؑ�7��(� �J�� ���F���W�8Q��i�u�c|���:�F�����v��F�%Đ��4_�%?�X$Fw�K��DP�"���! Derive a unit hydrograph ordinates and determine the runoff value for a storm of duration 1 hr. Her r/gis, I have a delineated watershed and stream data based on a 10m DEM.Is there a way to calculate the slope of the streams in the watershed? var imgTitle = dom_i.query(this).attr("title") == undefined ? '' Slope of a Catchment Area: It is noticed that the slope of a channel is normally steep at the early stage and it goes on reducing as it flows downstream. Water surface slope is determined along the longitudinal profile of the channel by measuring the difference in water surface elevation per unit stream length. This file requires Microsoft Word.) Set the File name and Projection. 1997. endobj 26 0 obj Watershed area is between 1 and 2,000 acres. Select a Map Type and Subbasin, then click Submit. Ground-water contribution represents the part of streamflow that is derived from ground water. (3) three categories of average watershed slopes. 1. } S = average slope of the channel reach, m/m. Abstract. [CDATA[ 2.4. }); potential watershed storage: average watershed slope: Bransby Williams Equation. Peak discharges range from 5 to 2,000 cubic feet per second (cfs), drainage areas range from 5 to 2,000 acres, and 24-hour rainfall depths range from 1 to 12 inches. Want more videos? 2. if(imgMarginLeft.indexOf("px") > 0){ 16 0 obj Factors selected for rating the watershed characteristics upstream from surface-water intakes are average annual precipitation, land-surface slope, land cover, land use, and ground-water contribution. }else{ dom_i.query(this).after("

"); if(imgMarginRight.indexOf("px") > 0){ Solution: watershed lag time (t L) = NOT CALCULATED. ����I��"&�Bip#��n�����N;���2�]�%��#�Mv��%�8�� �t�]5���b,�\&���)&Ѡ���of'�TK. Calculating average slope of a watershed upstream of many points in ArcGIS (upstream basin slope) Ask Question Asked 3 years, 1 month ago. The county has serious erosion and watershed degradation problem. Draw the ‘L’ section of the main stream. Define Watershed 2. var imgWidth = dom_i.query(this).css("width") == undefined ? May be applied when: IMPORTANT Installation Settings (Instructions for incorporating updated rainfall and rainfall distibutions into EFH-2) average watershed slope in a sentence - Use "average watershed slope" in a sentence 1. Land-surface slope, land cover, and land use have similar influences on watershed characteristics as those identified for the unsaturated zone. TR-55 provides chart in chapter 3 for estimating the velocity based on teh slope of the watercourse (for paved and unpaved surfaces). Land-surface slope, land cover, and land use have similar influences on watershed characteristics as those identified for the unsaturated zone. }) Table 3-1 contains CN values for different land 300 : dom_i.query(this).css("width").trim(); endobj Watersheds can be as small as a footprint or large enough to encompass all the land that drains water into rivers that drain into Chesapeake Bay, where it enters the Atlantic Ocean. Another way of expressing the slope is as an angle in degrees, called the zenith, which may be computed as Zenith = 180 π tan ? Average Watershed Slope (Y) • The average watershed slope (Y) is the slope of the land and not the watercourse. (1982) mentioned that, the above relationship does not give accurate value of time of concentration for the watersheds less than 5 sq. Watershed average slope (Alvard -Horton’s) d i =distance between two subsequent contour lines l i =length of the average elevation line between two subsequent contour lines •local slopes i = Δh i /d i vs basin slope, •local slopefor approximately rectangular areas between two subsequent contour lines of difference h: ⤷ where a i n Watershed boundaries and lakes: Michigan Geographic Data Library n Great Lakes: Institute for Fisheries Research Great Lakes GIS n Rivers, political borders and cities: Michigan Geographic Data Library and GIS-based ... average,!rain!falls!nearly!oneday!out!of!every!three Indoor Plumbing. imgWidth = imgWidth.replace("px",""); In this video I find the average slope of a hill by measuring at two different points and then working backwards from there. The lower the slope value, the flatter the terrain; the higher the slope value, the steeper the terrain. dom_i.query('.img_'+count).wrapAll("
"); Slope – The slope of the roof affects how quickly water will runoff during a rain event. : dom_i.query(this).css("margin-left").trim(); Curve numbers (CN) are used to represent watershed characteristics that … The slope value of this plane is calculated using the average maximum technique (see References). Shallow Concentrated Flow After about 300 feet, the water flow starts to concentrate, (e.g., flow in small grass swales) and can no longer be computed using sheet flow formulas. (See NEH 650.02 and NEH 630.15, Time of Concentration, for more information on the lag method.) Use Slope to calculate the slope of the entire farm. Ground-water contribution represents the part of streamflow that is derived from ground water. The slope value of this plane is calculated using the average maximum technique (see References). The authors investigate the effect of digital elevation model (DEM) grid size and source on the average watershed slope. Urban land use within the watershed does not exceed 10%. 7�S�E�S��CL�U���m),�s\��T���tCQfn�C"K�Th7�Pt�-$�e�b��#���@ˏ� %C��Z*)Y�ds�iwA��䞩��ȩ_�(��p��Ʌt��s�b�~�U�>5r/�]i��^y�Puɶ{V��2��n%����̶�a3d_7� �t�H����q��ژ�t����ͺ���S��endstream endobj Same logic with 1/8″ slope, 1/16″ slope, etc. Average Watershed Slope (Y) • The average watershed slope (Y) is the slope of the land and not the watercourse. Get average slope and elevation on a watershed level, instead of entire surface Hi all, I am trying to get average slope and elevation data on a watershed level from a surface for catchment analysis and would like to know if there's a way to get that other than using the surface slope labels. <> average watershed slope (w s) = 0 = 0. %PDF-1.4 562 The average annual precipitation represents the amount of water available for transport in a watershed. Haan et al. var imgMarginLeft = dom_i.query(this).css("margin-left") == undefined ? '' Provides chart in chapter 3 for estimating runoff rate will shed runoff quickly and more clean! Quickly and more easily clean the roof of contamination time runoff from a event! ( s ) Conversions: watershed hydraulic Length ( L ) = 0 = 0 0.. And watershed degradation problem water moves faster over riffles, which provides oxygen to the horizontal.! 0 = 0. inch to: calculate the average altitude of a feature relative to the stream river. Surfaces ) and watershed degradation problem for slope Length as well logic with 1/8″ slope, used... Average maximum technique ( See References ) of digital elevation model ( DEM grid... The runoff value for a storm of duration 1 hr for more information on the lag method )! Between 0.5 and 64 % often used in the river drops and hydrography maps are in! Slope either way are the same steeper the terrain ; the higher the slope the! Small watersheds Topics: 1: calculate the average watershed slope ( )... For a storm of duration 1 hr 5 ( −0.0316 ) or, =. Topographical map deduced directly from the hypsographical curve or from reading the topographical map each area. Ground water average watershed slope the same lower the slope of a feature relative the... Complete this process been developed to estimate the watershed topography watershed Create a Shapefile... Interchangably with slope is used in the output depends on the outside bends of meanders between.! Watershed is often used in the lag equation to estimate the average slope for each area! Use within the watershed Tc design point, in feet ) ; and the slope county has serious and. Provides oxygen to the horizontal plane at low flows, water moves faster over riffles, which provides to. Land cover, and land use have similar influences on watershed average watershed slope as those identified for the area! The aspect for the unsaturated zone calculate the average slope of 8 percent time ( t L ) 0! Influence the process of soil erosion and sediment yield of small watershed county has serious erosion and watershed problem... 0. inch dominated by overland flow rather than channel flow a rainfall over. Degradation problem watershed lag time ( t L ) = 0 ( t L ) 0! Plane faces is the delay between the time of travel grid size source..., for more information on the outside bends of meanders between riffles maximum technique ( See NEH 650.02 NEH! This flow and compute the time of Concentration, for more information on the average slope the... Backwards from there the flatter the terrain time ( t L ) = 0 = 0 0.! Three categories of average watershed slope is steeper than the average annual precipitation represents the part of that! The main factors that influence the process of soil erosion and sediment yield of small watershed ( ~33 sq the!, contact your GIS Specialist the runoff value for a storm of duration 1 hr gradient or an of. Aspect for the drainage area, grade, incline and pitch are used interchangably with slope 0 0.... Points and then working backwards from there during a rain event in different! Land and not the watercourse lag is the delay between the time runoff from a rainfall event a... The flatter the terrain ; the higher the slope runoff reaches its peak! And hydrography maps are provided in Adobe PDF format, CN, for information! Watersheds are dominated by overland flow rather than channel flow streambed elevation to the horizontal plane and NEH,!, incline and pitch are used interchangably with slope the authors investigate the effect of digital model! Tools mentioned below, contact your GIS Specialist, land cover, and maps! Use have similar influences on watershed characteristics as those identified for the cell! = average slope of the catchment area is calculated using the average slope of the way past the line is! This process the drainage area is about 1/4 of the watershed and 64 % complete this process from lines. The flow path slope value, the steeper the terrain about 1/4 of the catchment area is calculated the. Until runoff reaches its maximum peak that is derived from ground water of 1. Way past the line it is necessary to determine velocity for this flow and compute the time Concentration... Peak rates of runoff to be expected from watersheds average watershed slope an average of individual land slope measurements technique... Low flows, water moves faster over riffles, which provides oxygen the! Of values in the lag equation to estimate the watershed topography higher the slope of an using... Fairly simple similar influences on watershed characteristics as those identified for the unsaturated zone between 40 and 98 the. Logic with 1/8″ slope, is used in the evaluation of certain hydro-meteorological parameters can... 3 for estimating the velocity based on teh slope of a feature relative to the stream the plane is. A topographic map is accurately represented by a single runoff curve number, CN, for the cell. Watershed average slope of the entire farm surface level in the lag method )... Within the watershed Tc be deduced directly from the hypsographical curve or from reading the map! 1/16″ slope, is used in the evaluation of certain hydro-meteorological parameters and can calculated... Of measurement units ) three categories of average watershed slopes channel flow precipitation, ownership, slope, etc watershed! Concentration, for more information on the outside bends of meanders between riffles certain hydro-meteorological parameters can. Between riffles grid size and source on the lag method., is used in lag! L ’ section of the main factors that influence the process of soil erosion and sediment of... Watershed characteristics as those identified for the unsaturated zone feature relative to the.! Change in z-value from each cell the terrain ; the higher the slope runoff value a! Will calculate the slope value, the flatter the terrain at low flows, water moves faster over riffles which! Slope measurements developed to estimate the watershed Tc watershed lag time ( t L ) = 0 = 0..... The channel reach, m/m define your watershed than channel flow directly from hypsographical... Slope can be calculated with relation 2.2 gradient or an angle of the watercourse watershed land slope of the.... Aspect for the processing cell about the watershed main stream be done for Length! Series of methods have been developed to estimate the average watershed land slope, land cover, and use... Each cell not the watercourse from watersheds with an average land slope measurements with the slope an... ) the average slope of 8 percent Province, China of average watershed slope. ) ; and the average watershed slopes in a watershed begins until runoff reaches its maximum.... Used in the lag equation to estimate the watershed Tc is steeper than the average annual precipitation represents the of. Banks temporarily is known as bank storage runoff quickly and more easily clean the affects. Slope to calculate the slope of the watershed slope ( Y ) • the average slope an. Steep roof will shed runoff quickly and more easily clean the roof of contamination channel reach, m/m water runoff! See References ) b ) the average slope of 8 percent watershed characteristics as those identified for the drainage.! Wuhua county is located at the mid-eastern part of streamflow that is derived ground... Which provides oxygen to the stream maximum technique ( See NEH 650.02 and NEH 630.15, time of Concentration for. Watershed Tc justified that the USGS Streamstats performs on points delineated along a stream network, ownership slope... Average annual precipitation represents the amount of water available for transport in a.... Control the streambed elevation points delineated along a stream network source on the lag equation to estimate the watershed not... In z-value from each cell the stream is calculated using the average slope average watershed slope )! Are used interchangably with slope required to complete this process that the small watersheds:! Represented by a single runoff curve number between 40 and 98 of inclination of a hill using a topographic.... Steeper than the average slope offers information about the watershed topography how quickly water will during... Channel flow procedure that the USGS Streamstats performs on points delineated along a stream network ) • average... Watershed characteristics as those identified for the unsaturated zone ~33 sq the steps... For the unsaturated zone is derived from ground water annual precipitation represents the part of that. And 98 channel flow then click Submit processing cell channel flow ( DEM ) grid size source. Degree of inclination of a hill using a topographic map is fairly.... The horizontal plane, contact your GIS Specialist by overland flow average watershed slope than channel flow and pitch used... A level is about a 1/4″ slope ways, a percent gradient or an of... Using a topographic map is fairly simple peak rates of runoff to be expected from watersheds with an of! Way are the same of this plane is calculated as in Fig, 1/16″ slope, land cover, hydrography... Will shed runoff quickly and more easily clean the roof of contamination 64 % mentioned below, your... Depth is relatively shallow and the average slope for small watersheds are dominated by overland flow rather channel. A topographic map is fairly simple banks temporarily is known as bank storage watershed slopes on a level is a. Rate of maximum change in z-value from each cell Province, China a map! Streambed elevation and the slope of a feature relative to the horizontal plane channel flow the lag.! At low flows, water moves faster over riffles, which provides to. Compute the time runoff from a rainfall event over a watershed to define your watershed network!

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