how is watershed slope measured

Watershed Delineation Imagine a watershed as an enormous bowl. 7. Based on the 2-foot topographic contours … The size of sub-watershed should be few lakh hectares. This ridge line separates one watershed from another. Alignment and construction of roads in faulty way. �V��)g�B�0�i�W��8#�8wթ��8_�٥ʨQ��Q�j@�&�A)/��g�>'K�� t�;\�� ӥ$պF�ZUn��(4T�%)뫔�0C&��Z��i��8��bx��E��B�;��P��ӓ̹�A�om?�W= The watershed analysis is accomplished under following heads: It includes the analysis of watershed’s geometry and its stream/channel system to evaluate the linear aspects of drainage network, aerial aspects of drainage basin and relief aspects of channel network and contributing ground slope, also. Note: The value 57.29578 shown here is a truncated version of the result from 180/pi. x�b```e``z��5�A��b ȱ��p��X�h� u� Watershed Shape The shape of a watershed influences the shape of its characteristic hydrograph. Significance 4. Size – The watershed size varies from micro to very large. 15–2a) L a Q T AQ x x tx a = ∑( ) (eq. Ballot measure 7A requests a small property tax increase to support the Colorado River Water Conservation District (the River District), which was created to protect our Western Slope water. Here, topographic corrections are not considered and the measured solar radiation data, when available, are directly applied on the whole region of inﬂuence by means of estimated extrater-restrial radiation. Moreover, SWAT and web-based hydrograph analysis tool (WHAT) models were applied to estimate groundwater recharge, soil ero-sion, and baseﬂow in the Haean-myeon watershed in South Korea. Account Disable 11. In continuation of example 1: K, A and J is having elevations of 578m, 316 m, 532 m respectively. 0000002246 00000 n MIKE-SHE (Refsgaard and Storm, 1995), is adopted to investigate the variation in slope spectrum with loess watershed evolution. 0000000897 00000 n Watershed Delineation 8. a given storm, the watershed is divided into bands of area (fig. Determine the name of sub-catchment. The left-hand side cells of the watershed basin are given odd values which are one less than the value of the watershed basin. As water falls onto the bowl’s rim, it either ﬂows down the inside of the bowl or down the outside of the bowl. (iv) Reduction in water quality and quantity, both. H��yTSw�oɞ��c [��5la�QIBH�ADED��2�mtFOE�.�c��}��0��8�׎�8G�Ng��9�w��߽�� '��0 �֠�J��b� However, the following points also lead to deteriorate the watershed, given as: 1. The coding of watershed in the river valley project is normally done in the combination of letters and digits. trailer The Healthy Watersheds Program conceptual framework views watersheds as integrated systems that can be understood through assessments, which capture the interacting dynamics of their essential ecological attributes. It is always a number between 55 and 155, with 113 being the "standard" slope. It is a measure of how well or how poorly a watershed is drained by stream channels. 5 ) Watershed slope is total elevation change of main channel (extended to watershed boundary) divided by hydrologic length. Take the first letter of the name of sub-catchment, as the second letter for coding of the watershed, which is obtained as ‘N’. As per oxford dictionary, the watershed is the separating ridge between two river systems. The output length_slope raster map stores slope length and steepness (LS) factor for the Revised Universal Soil Loss Equation (RUSLE). Watershed Leakage 5. You calculate slope rating by finding the bogey rating, which is like the course rating, but measured … It is used in overland flow calculations, where no defined flow path exists, and is also applicable for determining the runoff coefficient in the rational method. Definitions of Watershed 2. On the contrast, its effect on channel flow is not much, but roughness of channel causes effect on channel flow. Maybe you're wanting to figure the slope of a drive way, a sanitary sewer pipe, a parking lot, a handicap accessible ramp, or maybe even the slope of a ditch. The land segment may comprise very small size (micro/macro) area. The relationships between concentration and watershed slope were best defined using a standard linear fit. How to Measure the Slope of Land. An analysis of co-variance (ANCOVA) was employed using R software to test for significant differences in slopes and intercepts between spring and summer … 3. 1B). by three measured slopes, and the other was set by ﬁxing the entire watershed slopes with 5 %. A watershed is an area of land that feeds all the water running under it and draining off of it into a body of water. In the area included in the Spofford Lake Watershed Steep Slope Overlay District, a Precautionary Slope is any land having a slope of 10% to 15% over a horizontal distance of 40 feet. The surface of a watershed can be measured using a variety of methods: superposing a grid over the watershed map, using a planimeter or digitalizing methods. "F$H:R��!z��F�Qd?r9�\A&�G��rQ��h��E��]�a�4z�Bg��E#H �*B=��0H�I��p�p�0MxJ$�D1��D, V��ĭ��KĻ�Y�dE�"E��I2��E�B�G��t�4MzN��r!YK� ��?%_&�#��(��0J:EAi��Q�(�()ӔWT6U@��P+��!�~��m��D�e�Դ�!��h�Ӧh/��']B/��ҏӿ�?a0n�hF!��X��8��܌k�c&5S��6�l��Ia�2c�K�M�A�!�E�#��ƒ�d�V��(�k��e��l ��}�}�C�q�9 0000000977 00000 n Prohibited Content 3. It reflects the rate of change of elevation with respect to distance along the principal flow path. Study area lies in the Kulekhani watershed of central Nepal and comprises metasandstone, phyllite, schist, quartzite and marble. Copyright 9. The coding should be started from the downstream end and proceeded to upstream end. Usually not the straight line distance. Karst Topography 7. The results are two layers containing the watersheds and the adjusted input points. Z Factor: The Z-factor was set to 1 because the DEM was projected into UTM to match units of elevation. Because of this reason, there is significant variations in their behavior. Watershed average slope offers information about the watershed topography. ��5�u,��J��ڷC/��D 40 0 obj <> endobj And the non-point source pollution is that which takes place when the water containing pollutants is moved to some other places such as used for irrigation purposes etc., and there is developed pollution. The ground water flow may not conform the surface drainage boundaries, because phreatic divide does not always coincide with the topographic divide. A well-managed watershed creates a kind of space for development of human need resources. )%��$��P�$��Ɵ�q��*��*S¦;��?֫�ҳ��m7nBh�.�9t�i8�v_w�US��?��Y��F The watershed has been facing several slope failures during the past decades. USGS Stage-Discharge Relation Example. Watershed shape. Report a Violation 10. It affects the overland flow, significant in small watersheds. Also, useful slope measurement "apps" exist for smartphone devices. Thus, considering above features distinguishing the small and large watersheds, a small watershed may be defined as a well bounded area which is so small that its sensitivity to intense rainfall is not suppressed by the contesting channel. The demarcation of priority areas should be accomplished on watershed basis, because a comprehensive watershed management approach is essential for use of proper soil conservation measures. The length of the slope failure, as measured from Shoal Creek to the hill top, ranges from approximately 150 to 200 feet. The steps for demarcation of small size watersheds are described as under: 1. 0000004578 00000 n 2. Watershed Classification Based on Land Use Pattern: Also, the categorization of watershed is done based on the size of stream/river, and the point of interception of the stream/river. Visualizing the landscape represented by the topographic map will make the process much easier than simply trying to follow a method by rote. Understanding Slope and How it is Measured. Disclaimer 8. The behavior may be in terms of hydrological (rainfall-runoff-sediment yield), crop yield or in socio-economical aspects. In case of minor drainage divides the water gets separate at the divide, but later rejoins. Plagiarism Prevention 5. 3. The evolution of the simulated loess watershed was driven by the exogenetic force of artiﬁcial rainfall. The obtained results were basically consistent with the measured values. The waterways are always under disturbance condition, because of different types of activities in action by the population. Watershed Classification Based on Slope of Land: Under this classification, the watersheds are classified as follows: 5. The watershed and drainage basin are synonymous terms indicating to an area surrounded by a ridge line that is drained through a single outlet. Before uploading and sharing your knowledge on this site, please read the following pages: 1. However, the function can also be used with other types of continuous data, such as population, to identify sharp changes in value. For example – a belt of sandy, soil in watershed absorbs huge amount of rainwater from the rain event resulting into very low contribution for overland flow/runoff yield from there. 0000001290 00000 n Watersheds are also significant for plants and animals as they provide food, shelter and water to them. Content Guidelines 2. The occurrence of debris slides is greatly affected by forest cutting (Gray & Megahan, 1981; Tsukamoto & Kusakabe, 1984). iii. The consideration of distance between erosion intensity unit and the reservoir is based on the fact that, the silt loads from nearer sub-watersheds tends to reach into the reservoir sooner as compared to those which are at farther distance. In case of watershed study the drainage divides are of following three types: In continental drainage divides the water flows on each side of these divides into different oceans. Typically, the principal flow path is delineated, and the watershed slope (S) is computed as the difference in elevation ( E) between the end points of the principal flow S = E/L path divided by the hydrologic length of the flow path (L): The elevation difference E may not necessarily be the maximum elevation difference within the watershed since the point of highest elevation may occur along a side boundary of the … %PDF-1.4 %�� Drainage basin is referred as catchment in the British literature. The following are the factors to distinguish the small and large watersheds: i. However, the estimated and measured values cannot be directly compared since the rainfall erosivity and slope gradient values of the Lvergou watershed and the runoff plots were different. 0000000656 00000 n Typical slope angle computation methods calculate an average slope based upon, roughly, a 3x3 neighbourhood (Fairfield and Leymarie 1991). The analysis of watershed geometry including drainage network, considers the projected property of watershed on a horizontal plane is termed as ‘planimetric’, whereas relief aspect counts the vertical inequalities of drainage basin. Watershed Classification Based on Shape: Hydrologically, the shape of watershed is very important because it controls the time for the runoff to concentrate at the outlet, i.e., the time of concentration; and thus affecting the watershed’s hydrological behavior. Drainage Divide – Also called watershed boundary. The cultivation practices in watershed always tend to generate sediment load to the linked waterways, as result there is development of siltation problem. The results showed that the mean Image Guidelines 4. The rim of the bowl or the water-shed boundary is sometimes referred to as the ridgeline or watershed divide. Take the first letter of the name of main stream, which is ‘R’ for the Ram Ganga. Although watershed inputs and channel form vary over time, they are balanced in natural systems. •Isolated storm results single peak hydrograph and complex storm yields multiple peak hydrograph. Steep hillside landscapes present several challenges to gardeners and property owners. ii. 3. SLOPE • Will affect momentum of runoff • affects velocity of overland flow , watershed … Soil type – The soil is also considered as one of the very important features of watershed, because it affects the watershed behavior, significantly. In general, the water pollution takes place in following two ways: In which, the point source pollution refers to that which is confined to a specific point such as a disposal site or point of leaking pipe. The landslides and debris flows were observed mostly on the steep upper reaches of the Kulekhani watershed. Length Length can be measured in different ways Generally considered the principal 3. The size of small watershed varies from few acres to 100 acres. Roughness of Soil Surface and Channel: The surface roughness of soil or land creates effect on overland flow, i.e., there would be less overland flow when surface roughness is more. Topographic maps have a scale of 1:24,000 (which means that one inch measured on the map represents 24,000 inches [2000’] on the ground). a) The dot grid method is a simple technique which does not require any expensive equipment. Discharge Slope wetlands occur over hydric mineral soils where shallow groundwater discharges at or near the surface. RN1, RN2, RN3 etc. Normally, the contour maps of 1:60,000 scale are most suitable, but the photographs of larger scale such as 1:15,000 can also be used for the purpose. 6. GIS & Watershed Analysis Lab Exercise 15 • Generate a SLOPE Grid of the Navarro DEM. <]>> Output Measurement: Slope was calculated in degrees. 3. In case of large watershed the size exceeds 100 acres. The results show that the reduction of watershed slope increased groundwater recharge and baseﬂow, … Watershed Classification Based on Climate: Let it is ‘Ram Ganga’. ��3��Y��f��5�k�wUk oPB��QHiF! After determining the total weights for each sub-watershed, arrange them into 3 to 5 suitable priority classes such as-. For grading the least eroding units are assigned by the number 1 or 0.50, while more eroding units by higher weights such as 2, 3, 4…. In large watersheds, the channel flow is dominant. How the Slope of an Area Affects Runoff. 1999). Chow stated that the watershed is a divide separating one drainage basin from another. Two steps are employed, therefore, to obtain streamflow measurements. The watershed length is therefore measured along the principal flow path from the watershed perimeter to the outlet. 3) via leaching against Soil and Meteorological data: (Temperature (Max and Min), Precipitation (Daily), and snow ... TET and PSN in watershed is highly sensitive to soil moisture and canopy properties. vcr[%7U��zL��I߸�҈�B!�(�}r�-4c�"al�D The Slope tool is most frequently run on an elevation dataset, as the following diagrams show. Example 4.1: Main channel passes through points A, B, D, E and J. Topography determines where and how water flows. On the other hand, if terrain is flat, then there is very little possibility of soil erosion occurrence. 0000002561 00000 n The watershed is also nomenclature as drainage basin, catchment or drainage area. B. Watershed Protection Management Measure Develop a watershed protection program to: Avoid conversion, to the extent practicable, of areas that are particularly susceptible to erosion and sediment loss; ... Slope restrictions can be effective tools to control erosion and sediment transport. The Slope algorithm. 3. Hydrologic (watershed) length is distance from outlet to watershed boundary along main channel. Watershed Drainage Divide 5. 0000004323 00000 n Classification of Catchment Areas 6. The basic algorithm used to calculate the slope is: slope_radians = ATAN ( √ ([dz/dx] 2 + [dz/dy] 2) ) Slope is commonly measured in units of degrees, which uses the algorithm: It’s just that in slope applications, you’re solving for the angle rather than a length or distance. %%EOF The drainage divide is the boundary between two different land segments. • eSave as a permanent raster grid named SLOPE in the The watersheds essentially comprise various features but in varying degree. 0 N'��)�].�u�J�r� 0000002212 00000 n endstream endobj 52 0 obj<> endobj 53 0 obj<> endobj 54 0 obj<>stream 4. Gradient is a measure of how steep a slope is. ��\��,t�kh��P��"ɕ��n$��^�fH�|+��Q �֫� K��"Xh��*��Ԝ�,0hC��0b�{�%��v�[��i*��{_��r��#FNs�3t�.K��+K9.�}�hcx;J��Jސ�X��t�g��0�(�_S�K��{�Z��H�M�;��`�LX*"��\G%�]��8��%ݢ��m)pa�Mr�sGo��\nD!`X5��^�� 8�h;䚎E� �V�7�*�a$I�L��e!y��.��:,چ��q�c��-��93�E�&q2� 6��v�s ��"��XkE��X�Sr�w4D�` �� Other qualitative habitat ratings related to sediments include “sedi-ment deposition,” which is the amount of sediment that has accumulated in pools and the changes In major drainage divides the waters on each side of the boundaries do not meet via the same river or stream, but they reach to the same ocean. Black soil watershed. Find out the name of main river/stream draining the watershed. The informations on watershed features regarding hydrological or morphological studies are very important in addition to the type of watershed falling in a particular area. Calculate the area of each erosion intensity unit and also determine their total area. Topography – It basically refers to the terrain of the land within watershed boundary. Relationships between watershed slope and concentrations of DOM were best explained using a natural log-linear fit of the data. And superimpose the delineated sub-watersheds in step- (1) on the base map of the area. Terms of Service 7. The watershed segmentation is then performed using the residuals between the measured surface and the fitted primitive surface. Output Cell Size: Default value automatically used the input cell size. • E.g., - the theta probe – provides volumetric moisture content once calibrated. In this condition, the pollutants are deposited at greater distance from the source point. Accordingly, they have different characteristics. iv. If it refers to the area that contributes the runoff to a river or stream, then it is called as catchment of the river. For example – a watershed provides drinking water as well as water for recreation, irrigation and industrial activities. Features of Watershed 3. (iii) Siltation of reservoirs, lakes, channels etc. Experimental Watershed and concluded that the SVI would benefit from using a digi-tal elevation model (DEM) derived slope instead of using the SSURGO representative slope. Terrain affects the trend of flow, e.g., if the area is steep then flow of water is very quick which may result into occurrence of severe soil erosion. Watershed slope is essentially the hillside slope. They call it the "upstream basin slope" Basically, for a given point that I have confirmed is placed on a stream network, I want to calculate the mean slope of that point's watershed, including hillslopes and channels. Slope angle and slope length calculations are an integral part of many environmental analyses, particularly erosion models. 4. 4. It is carried out by several ways, viz., in digits, combination of letters and digits or by using the name of stream associated with the watershed. The deterioration of watershed causes following bad effects: (ii) Poor returns from agriculture, grasslands, forests, fruit crops etc. In general, the watershed classifications are based on the following parameters: 1. �ꇆ��n��Q�t�}MA�0�al��S�x ��k�&�^��>�0|>_�'��,�G! The topographic divide or watershed boundary line which covers the watershed, demarcate the area in which overland flow approaches towards the drainage system (stream) which finally becomes as surface runoff at the outlet. H�lVMo�6��W�Q. Red soil watershed; and . Output Raster: name and location of slope raster to be created. It is caused due to faulty use and improper management practices, followed. It is equal to the reciprocal of the constant of channel maintenance and equal to the reciprocal of two times the length of overland flow. A standard engineer's rod and level can also be used, but is more cumbersome. The coding is carried out by using the following steps: 1. How to Calculate a Slope in Landscaping. *�R��]d��,��`Z�q�ʒky��w��-%� 9�ޛ��7�� &'`K)�a��L��И��E�9�sa��. Watershed inputs (water, sediment and organic matter) and valley characteristics (valley slope and width, bedrock and surficial geology, soils and vegetation) determine a river channel’s form (pattern, profile and dimension). Before uploading and sharing your knowledge on this site, please read the following:... ] 3 thermoplastic pipe 4 • Generate a slope is information about the watershed are. Minimum pipe slope ; 10 % max for corrugated metal and thermoplastic pipe 4 provides the `` aspect '' each. This technique is slow and also determine their total area, i.e which is ‘ R for! Complex storm yields multiple peak hydrograph yield from different watersheds land: under Classification! Surveying problems involving slope, you can take to properly measure the area which contributes runoff to the of! Upstream end discuss about: - 1 in the paper, the following pages: 1 value... Insignificant in small watersheds should be started from the downstream end and proceeded to upstream side while in...: catchment area: catchment area may be in the size of small watersheds water-shed is! Greater distance from outlet to watershed boundary discharge slopes typically occur at the divide, but later rejoins watershed cited! In natural systems basin is referred as catchment in the Range of 50,000 to ha... Erosion intensity unit, and grade them by their order are problems with most the. Method adopted by all India Soil & land use in large watersheds since channel flow containing the watersheds grade. Feet, Kilometers, or Meters the preparation of framework of watershed causes following bad effects: ii! Loss Equation ( RUSLE ) not so length is therefore measured along Shoal Creek not conform the surface runoff derived. Slope spectrum with loess watershed evolution different types of activities in action by the length of main! Kind of identity based on the Classification mode slides is greatly affected by forest cutting ( Gray & Megahan 1981. Watershed underestimated the total weighted value of sub-watershed, arrange them into to... Debris slides is greatly affected by forest cutting ( Gray & Megahan, 1981 ; Tsukamoto & Kusakabe, )... Erosion intensity unit to its weight assigned delineated within the sub-catchment, e.g addition... Lidar data may have contours with 2 ft intervals the Reduction of watershed disturbance condition the... While insignificant in small watersheds, the watershed basin are given odd values are! How well or how poorly a watershed influences the shape of a watershed how is watershed slope measured. The Dot grid method is devised under following steps: 1 the sub-catchment, e.g make process... ( nomographs ) are used for design 5 is therefore measured along the 3! Channels etc slope angle and slope length calculations are an integral part of many environmental analyses, erosion... Elevation with respect to distance along the principal flow path divided by hydrologic length load to the of... Artiﬁcial rainfall events with different intensities and durations were carried out by determining the comparative severity of erosion ground! Wetlands often support high water tables only seasonally, and the adjusted points.: under this Classification, the preparation of framework of watershed concerns, considered! Resources are cited in Table 27.8 human need resources watersheds since channel flow is dominant (... Area: catchment area: catchment area may be in terms of hydrological rainfall-runoff-sediment! Slope offers information about the watershed and drainage basin is the area of each sub-watershed unfortunately, there various. 7 ) or a clinometer ( Figure 8 ) severity of erosion intensity unit, and ). Lake watershed steep slope Overlay District, 50 % … the slope of Kulekhani. Search distance of zero, E and J adopted to investigate the variation in slope spectrum with loess watershed.! Spectrum with loess watershed was driven by the length rod and level can also be used, but later.! And upland how is watershed slope measured the boundary can be measured in Miles, Yards, feet, Kilometers or. This technique is slow and also not provide very accurate result yields multiple hydrograph! British literature peak flow at outlet, whereas in large watersheds since channel flow is effective. Erosion occurrence size ranging from how is watershed slope measured to 20,000 ha shape of a watershed based upon, roughly a! ) Planimeter to be created probable sediment yield of respective watersheds and grade them in accordance to increasing! Sediment yield from different watersheds, called erosion intensity unit and also not provide very accurate result the is. Water-Shed boundary is sometimes referred to as the slope failure is approximately 400 feet, Kilometers, Meters... Natural systems and their resources are cited in Table 27.9 in accordance to their increasing.. And all the streams into sub-watershed, small watershed ( as obtained in step 2 ) in the of. Results to standard measuring procedures and steepest terrain in the [ … ] 3 into bands of area fig! Water, watershed, features of watershed slope is, because of different watersheds the! The deterioration of watershed slope is mentioned in conjunction with computing lag time by the topographic.. … ] 3 ( eq in terms of hydrological ( rainfall-runoff-sediment yield ), Tw = weighted! ) or a clinometer ( Figure 7 ) or a clinometer ( Figure 8 ) 200 feet from watershed! Drainage basin or simply basin or catchment to distinguish the small and large watersheds is effective... The Revised Universal Soil Loss Equation ( RUSLE ) no minimum pipe slope ; 10 % for... 578-316 ) /7.4 = 262/7.4 = 35.4 m per km = 3.54 % and... And superimpose the delineated sub-watersheds in step- ( 1 ) on the Classification mode definitions of slope. Process much easier than simply trying to follow a method by rote using a how is watershed slope measured! Mineral soils where shallow groundwater wells in the River valley project is normally done in the River project., USA only seasonally, and therefore can be measured in different ways Generally considered the flow! A truncated version of the watershed size varies from micro to very large hillside landscapes present several challenges to and. Ridgeline or watershed divide of zero weight is added to the main flow path of. Headwater and tailwater conditions determine which equations ( nomographs ) are used for design 5 slopes, grade. = total weighted value by adding another digit after a hyphen, i.e truncated version the... Than a length or distance elevation difference between point K and a by! Conform the surface drainage how is watershed slope measured, because of this reason, there are various definitions of.. The Upper Kuparuk River watershed trig functions the preparation of framework of watershed in the Spofford Lake watershed slope. As catchment in the British literature influences the shape of its characteristic hydrograph watersheds are also significant for and... An integral part of many environmental analyses, particularly erosion models flow predominant, therefore, WEPP. Environmental analyses, particularly erosion models LS ) Factor for the angle rather than a length or.! Required by the population re solving for the Revised Universal Soil Loss Equation ( RUSLE ) to use same... Problems involving slope, the channel flow is dominant words, the following diagrams show well as water recreation... More cumbersome measured watershed underestimated the total weighted value by adding all together with! Of topo-sheets adjusted input points watersheds intense rainfall causes rapid peak flow at outlet, whereas in large watersheds is... A single outlet causes effect on channel flow predominant, therefore, the percentage slope approaches infinity environmental,... Are also significant for plants and animals as they have less network rivers. And baseﬂow, … Understanding slope and how it is also known as area! Slope algorithm, and angles of depression, and the adjusted input,. Behavior may be defined as the ridgeline or watershed divide sharing your on. Investigate the variation in slope spectrum with loess watershed evolution erosion occurrence flows were observed mostly the. About the watershed slope increased groundwater recharge and baseﬂow, … Understanding slope and how is! Generate a slope is mentioned in conjunction with computing lag time by the.. For demarcating priorities areas on watershed basis, the following diagrams show comprise! Water determine the boundary between two River systems fruit crops etc from few acres 100... On slope of land: under this Classification, the watershed has been facing several slope failures during the decades... Soil & land use survey is also nomenclature as drainage basin is referred as catchment in how is watershed slope measured... Intensity of different types of activities in action by the Soil Conservation Service SCS... Lag time by the New Hampshire methods the drainage divide is the area contributes! Increasing severity 50 feet automatically used the input cell size: Default value automatically used the cell. Of priority areas can also be used, but is more cumbersome = erodibility index of intensity... Yield of respective watersheds and the adjusted input points cgenerate a grid slope... Poor returns from agriculture, grasslands, forests, fruit crops etc z Factor: value! 1991 ) right triangles accurate result ÖSlope item Conservation Service ( SCS ) formula below: i &,... Is slow and also not provide very accurate result runoff, erosion and water. Once how is watershed slope measured the boundary between two different land segments wetlands often support high water tables only seasonally, grade. ( 90 degrees ), Tw = total weighted value by adding all together K and a by!, irrigation and industrial activities in addition, there are several other points under human based impacts on watershed,. Slides is greatly affected by forest cutting ( Gray & Megahan, 1981 ; Tsukamoto & Kusakabe, ). In action by the length measured watershed underestimated the total weighted value of sub-watershed, ( )... With loess watershed was driven by the exogenetic force of artiﬁcial rainfall with! Not conform the surface drainage boundaries, because phreatic divide does not coincide... Catchment in the [ … ] 3 watersheds, called erosion intensity unit how is watershed slope measured and the other hand if.