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Dear Authors/Scientists/Academicians
I would like have a discussion on the monitoring of river (water level/discharge) for early warning We would like to use non contact type of sensors in the Kosi basin of Bihar in India to understand the flow variability and impact on flood. I wanted to know the following
1) How to choose the site for deploying the sensors
2) How to select the sensor type for this
3) What are the criteria to decide the optimum number of the sensors in a watershed.
4) How to generate the cross section to evaluate the discharge.
5) In absence of historical data, how one can develop the model (Rainfall-Runoff)
6) What are the open source software to carry out hydrological model other than HEC-HMS
7) For developing the hydrological model, what the data set we required other than (DEM, LULC, Soil Map)
8) Any technical guide/paper to divide the sub watershed according to gauged sensor
9) How can we best use of dense network of AWS and ARG in that watershed.
10) Best tool to analyze the hydrograph
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River Flow Monitoring and Data Quality for Equitable Nile Water Sharing
  • August 2020
  • Conference: The 2020 International Conference on the Nile and Grand Ethiopian Renaissance Dam: Science, Conflict Resolution and Cooperation, FIU (virtual)
  • At: Virtual Zoom Conference
  • Affiliation: Florida International University
  • Project:
  • 2020 International Conference on Nile and Grand Ethiopian Renaissance Dam (GERD): Science, Conflict Resolution and Cooperation
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In first order watersheds, can the shape index (Ff=A/Lb²) and the elongation ratio (Er=(2/Lb)*(A/Pi^0.5) return values >= 1?
Working with large watersheds, these values tend to be < or = unity. However, working on small hydrographic basins (1st order) I find some volers above the unit.
Is there any convention that the values of Ff and Er cannot exceed unity?
Thanks.
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It is necessary to define the parameters which are in your formula Ff=A/Lb² because in this form Ff is not dimensionless.
Usually, the following parameters are defined for the watershed:
1. Form factor: Watershed Area/(Watershed length)2 = A/L2, Value < 1
2. Shape factor Bs : (Watershed length)2/Watershed Area = L/A2, Value > 1
3. Elongation ratio: Diameter of the circle of watershed area / Watershed length = 1.128A0.5 /L, Value < or equal to 1.
4. Circulatory ratio: Watershed area/Area of the circle of watershed area = 12.57A/P2, where P is the watershed perimeter, Value < or equal to 1
5. Compactness Coefficient: Watershed perimeter/perimeter of the circle of watershed area = 0.2821P/A0.5, Value > or equal to 1.
Regards
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Dear Researchers,
Please share methodologies to quantify the hypothesis that the "reduced evaporation" and "increased transpiration" from tree cover area (forested region) results in increased water conservation.
Thank you!
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Please read the following article; will be useful to find balance between reduced evaporation, and increased transpiration
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Dear Researchers, Water Managers, Climate Experts, and Policymakers,
By understanding the ways in which ancient communities were successful at or failed in attaining sustainable water management, recent studies have attempted to provide important information for modern communities facing climate change impacts which are consequently resulting in water scarcity, security, safety, and sustainability issues. For example:
Can the perspective of re-implementing ancient and indigenous techniques of water management in contemporary conditions be considered as an imperative proposition to drafting modern water management policies? Your opinions, observations from your case studies, and evidence from your published work, if shared, will be gratefully appreciated.
Yours Sincerely,
Aman Srivastava
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Depende del contexto y las condiciones para su aplicación.
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Watershed development is the set of practices to impound the flowing rainwater, and thus help it percolate. But the groundwater recharge is also dependent on many other factors like the amount of rainfall, rainfall pattern, topographic slope, soil type, soil thickness, rock type etc. How do we measure the impact of watershed development on the groundwater?
Please do share publications on this topic.
Thank you.
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As pointed out by Kiprotich Kiptum, one needs to look into quantifying the declined yields. To put it more appropriately, the concretization or increase in the imperviousness of the watersheds will decrease the natural recharge rates that will impact the water tables.
So if the water tables are decreasing, it is a direct consequence of the development, (yes if development here means concretization)!
There are different methodologies for quantifying this issue, and they are discussed elaborately in literature.
I hope this has worked!
Thanks and regards
Gowhar Meraj
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I am studying mobility and socio-cultural interactions among palaeohistorical hunters-fishers-gatherers in the Laurentian part of the Subarctic. My main research hypothesis is that rivers and watersheds are "vectors" that had a structuring role on mobility and social interactions. Since I am interested in examples that has been documented around the world, can you recommend me ethnographies, archaeological publications or researchers that have studied watershed in order to understand cultural or sociological phenomena?
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Dear Olivier,
You may want to have a look on the paper of my former colleagues Tomaž Podobnikar:
Kind regards,
Balázs
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There's any software able to efficiently simulate snowmelt runoff paths on a specific surface (also looking at the geomorphology, e.g. considering available DEMs), starting from local snowmelt runoff measures?
>> More details: I have punctual values of snowmelt runoff (m3/s), crossing the end section of a watershed, but I would like to find out a solution so as to spatially simulate snowmelt runoff flows on the entire watershed, looking at the values obtained to its end section.
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How can we integrate flow and sediment data for flow and sediment calibration during the watershed hydrological modelling? Because they do not explain the watershed reality. Since the time series will not have the same metrological data.
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you need to take real-time field measurements of precipitation, flow and sediment amounts of the study area at least for a year or two, then you should use these field data to calibrate with the results provided by the modelling you used..
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Dear Researchers,
I run multiple times my SWAT-CUP SUFI2 but it is contineously giving this problem as attached in picture. Please let me know your expert opinion why I am facing this error and how to fix it.
Thanks in Anticipation.
Kind Regards
Naveed
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how to solve the SWAT_CUP error dispalyed in figure below.
with regards
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Because I see that to estimate soil loss throught USLE, RUSLE models, some researchers use models that are not compatible with the study region?
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If referring directly or indirectly to the USLE R factor, sometimes called the rainfall runoff factor, it is developed from the frequency and intensity of rainfall events, on average, for specific areas. The US has a map developed for this. The rainfall intensity is one of the driving energy factors or forces that is accumulated into an energy R factor from long term rainfall records. Rainfall rates exceeding 3 inches per hour are apparently the maximum rainfall intensity applied as either the amount sufficient to dislodge soil particles, or perhaps that rate on agricultural soils often leads to puddling, which absorbs any added energy from more intense events. Soil loss estimates through USLE and associated equations do not include any erosion associated with channelized flow, it is basically what one might call sheet erosion and sheet flow. The USLE estimates the dislodgement, entrainment of soil particles in this surface flow and movement and deposited to another area or delivered to a channel network. Since rainfall is the driving force for particle dislodgement, it seems that soil loss models would have to consider local or regional rainfall information. Wind blown soil is another force consideration that is not evaluated in rainfall or runoff with USLE soil loss estimate.
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The check dams used as torrent control works have some characteristics - in my opinion - which are neither quite those of retention dams (hydraulic structures) nor quite those of retaining walls. So, taking into account their behavior over their period of existence (50 to 100 years), a short period the check dam works as a hydraulic structure subject of hydrostatic/hydrodynamic pressures. Then, after the upstream sector is completely filled with sediments, it works as retaining wall, perodically submited to floods. I put this question because, verifying such a structure using Eurocode 7 I obtain larger dimensions than using the old global factors of safety. And a more than 100 years of experience shows that economically the last approach is better. 
According with the experience and technical regulations in the European countries, are them subject of Eurocode 7 or of some special regulations? 
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Check dams reduce erosion of the area around the highway. They can be designed also using EC 2 ON CONCRETE STRUCTURES.
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I am new to HEC HMS. and i am thinking to perform rainfall runoff modelling of a basin near my area using HEC HMS. The data i have is rainfall time series data and flow data of my outlet point. I want to estimate the discharge and compare the discharge obtained from the model to that of the real observed data..how can i perform the modelling without using soil data as i dont have any soil data or soil classification data of my region (for SCS CN method)?
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You actually do not need a soil map to set a HEC-HMS model or to calibrate it. It is a conceptual model, so lot of things are approximated. Of course you can use soil and land use to get the Curve Number and other related parameters in GeoHMS but during calibration they are likely to change also. So, a better idea is, do a literature search, start with reasonable values of soil related parameters and do the calibration and validation for streamflow simulation.
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Despite its importance in watershed hydrology and management, until now I know CN-model is a manually operated model. If there are some experiences I would like to hear from the group.
Best
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The CN value has to be estimated outside a numerical model. Given GIS-based soil and land use data, the CN value can be automatically calculated in AcrGIS. Once estimated this or any other way, the CN is input to numerical models and subsequent calculations are again automatic. This is the current situation. However, if you want you can connect the two automated processes and make the whole thing automatic.
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Our recent study base on delineating and establishing paired watershed in two different vegetation types in Sri Lankan rain forest. Please shire your experience with any countries or regions
thanks
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thanks for your advises
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Coefficient of determination R^2
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Coefficient of Determination and Nash-Sutcliffe Efficiency are based on least squares so give greater weight to the peaks. A high CoD can indicate the peaks fit well but not the recessions. You can get a better idea of the fit of the recessions by taking logs. There are other measures you can use if you trawl through the literature however I used a combination of NSE and logNSE to indicate the fit of my models when working on my PhD. However what value to pick is a very good question - the answer to that is dependent on so many factors and is often a case of as good as you can get given the uncertainties involved. Good luck. It is probably good practice to determine your limits of acceptability before you start to model then throw out any models that don't comply - again trawl the literature particularly the work of Keith Beven.
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A 10, 20 or 30 year period will just be fine. I have got some few maps showing some trends but I need figures to plot some graphs
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Pls how can get rainfall and temperature data for Nigeria between 1971-1981
......pls if any one has pls help me .I need it for my undergraduate project
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The inflow prediction in the reservoir is a very important and challenging task for the reservoir operation. However, in a large basin, there are many sub-catchments. So initially, one needs to forecast inflow for individual sub-catchments and then sequentially progressing downstream to forecast inflow into reservoir. Which data driven or artificial intelligence technique will be more appropriate for such application?
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The last version of TOPKAPI ( (TOPographic Kinematic APproximation and Integration) Distributed Hydrological Model, called TOPKAPI-eXtended or TOPKAPI-X, free software and open source.
MAIN MODIFICATIONS IN TOPKAPI - eXtended Model:
1.- Introduction of an 8-DIRECTIONS drainage network
2.- ADDITIONAL SOIL RESPONSE in order to reproduce different hydrological situations. Two soil layers
3.- Addition of an infiltration module based on the GREEN-AMPT MODEL, to reproduce hortonian processes
4.- Introduction of two coefficients to take into account the sun height with respect to the cell aspect for the RADIATION ASSESSMENT and ALBEDO
5.- Addition of a GROUNDWATER MODEL based on the cellular automa: full 2-D IFD (integrated finite difference) groundwater model 
6.- Development a powerful graphical interface linked to GIS
7.- Development of module adapter for DELFT-FEWS (Deltares) for operational hydrology and flood forecasting
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Yah really used full software to use it in hydrological fields like flood forecasting.
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I want to calculate watershed health using different parameters. The above mentioned parameters are part of the analysis.
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Dear Ravirej,
No, I don't think so. The index is a function of both the slope and the upstream contributing area per unit width orthogonal to the flow direction.
Regards
Bachir ACHOUR
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Dear Researchers,
I have calibrated and validated my swat project for a particular Landuse rasyer data set.
Now, I want to develop Landuse change Scenarios in this swat project.
Plz guide me.
Kind Regards
Naveed
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Hi Naveed Ahmed. I normally analyze LU change scenarios as follows. First I calibrate and validate SWAT with the current LU scenario or whatever your baseline scenario is. Next I will re-run the model but modifying the LU input raster according with the scenarios of interest, and using the calibrated parameters that you came up with during the Calibration process. This approach implies that you create your scenarios of interest out of the model according with the problem that you want to analyze. One simple example would be analyzing a deforestation risk map you may identify future scenarios. SWAT also allows you to analyze BMP inside the model.
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Dear Researchers,
I have created the soil user file and now working of LULC file. I have done almost all only remaining are following:
Townland and
Ruralland
Both belongs to urban landcover, so its code must come from Urban database and accordingly code ID will be assigned in the user define Land-use text file. AM I right?
Secondly, Desert, Dryland and Plaindryland I am still struggling how to replace them from the land cover closest category.
Could you please guide me how to fix these problems.
Thanks in anticipation.
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Dears all
I would like to know what are the relationships among watershed health, watershed sustainability and watershed stability!
Please share your experiences with me.
Thanks
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A healthy watershed, contributes to watershed stability. Different types of internal habitat and structure diversity also help to diversify the system and provide for increased stability .
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Hydrological drough severity and suspended sediment yield.
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Soil is variability
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I have studied an area of rain forest which presents a strong gradient of variation in soil moisture and nutrient. The florestal inventory was conducted in 42 plots of 5-25 meters, distributed in seven lines going through three compartments, in order: 1) A floodable plain forest in a organic soil; 2) Intermediary assembly located in a soil with a steep slope; and 3) a dry forest located in the highest place, with poor white sand soil.
For now, i intend to evaluate the water table variation, but i´m not sure how deep and how many piezometers should be needed to perform multivariate analyses involving plant community and soil water content. Initially, would be interesting install 42 piezometers, 1 per plot, but this would be very difficult to perform. Besides, i am not sure if piezometers of 1,5 meters would be deep the enough to access predictive informations about the influence of soil water content in plant community composition.
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Hi everyone anyone have the complete answer for those questions?
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I am looking for data set to develop a flood forecasting system specifically for an agriculture dominated watershed. The requirements include a) fine resolution DEM b) land use type and soil hydrologic group c) hourly/sub-hourly rainfall data for a minimum of 30 years d) hourly/sub-hourly stream flow data and e)demographic details of the area. It would be helpful if you suggest any data repository/experimental watershed for collecting the above mentioned data. I assure you that the services offered will be duly acknowledged.
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I agree with previous two answers. I must say that there is no single repository of datasets for the whole world. Most often GIS repositories are at state or country level. DEM is most commonly available GIS data. Land use could be variable in resolution depending on the country. In regions where there is no land use maps, you could use remote-sensing to define a better land cover map. Soils data is mostly FAO dataset V2, which is coarse in scale. Soil surveys with countries have better resolution. For rainfall time series, try to contact your meteorological department. You need many stations for watershed modeling. Streamflow is often used to calibrate and validate and often available only in long-term monitoring stations. Many rivers are ungauged in the world. For demographic information, census is best but is available at census district levels. If you can specify the watershed you are planning to model, I can suggest datasets better.
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We observed a huge difference between simulated and observed outflows from a catchment during a hydrological modelling exercise in HEC-HMS. The catchment contains numerous ponds and smaller lakes (of varying areal extent), lacking operational data. How can we account for the effect of these storage structures in the hydrological modelling?
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I am not totally familiar with HEC-HMS. I believe that it runs by reaches, with a stage, storage, outflow for each reach, is that correct? If so, then you need to make each reservoir along the river to to have its own stage storage outflow information. This is challenging modeling, so it will take some time to fully describe each of the reservoirs.
If you are modeling the upland runoff to HEC-HMS using the Curve Number methodology, there is a way in the method to account for the effect of reservoir storage in the sub basins. Let me know if you need some suggestions on how to do that.
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What data do we need?
I got 35 years of daily data of rainfall and river discharge.
I am working on this project for my final year research project in civil engineering.
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I think most kinds of ANNs could well simulate the river discharge with the previous observed streamflow and current rainfall data. But those works highlight the predicted discharge only. Hence, if for something new, your point should focus on if the LSTM can reasonably reflect the mechanistic processes. Specifically, the soil moisture has the memory of previous wetness in a watershed, which may be suitable for the function of short-term memory in LSTM. It means soil moisture productions made from remote sensing or land surface modeling may be useful for your research project. Moreover,some of my work published in 2013 and 2014 could be helpful, as well.
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Dear Researchers, I have daily flows data 1961-2015 and some of the months flows data is missing. This missing period varied; 1 mont, 1.5 months, 7 months, randomly. I would like to ask how to generate this missing data? Please share your expertise and skills. Thanks in anticipation Regards Naveed.
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Hi Naveed,
Assuming you have temperature and precipitation data, you could setup and calibrate a rainfall runoff model to predict missing flows. If instrumental data are not available, most places in the world have gridded meteorlogical data which often works better for runoff simulation than direct measurements from a met. station. You could make the met data as simple or as complex as you like, we've had surprisingly good results for most of the Indian subcontinent using a single precipitation and temperature time series to model river flows. There are a range of straight forward and easy to use rainfall runoff models. My group has had success with Jan Seibert's HBV-Light model and my PERSiST model.
Sincerely,
Martyn
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Dear colleagues,
I am looking for runoff data (ground or satellite) especially for Khartoum, Sennar, El Deim, Kessie and Bahir Dar stations during the period (2008-2018).
Thanks for any help.
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Dear colleagues,
can anyone tell me how can I get the surface discharge of D.S. Jebel Aulia on the White Nile river for any period after 1998.
Thanks in advance.
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I am almost always working on a catchments without river discharge. I am trying to think of a smarter way of calibration the rainfall-runoff (RR) model. Common practice has been to calibrate nearby catchment with data and transfer the parameters. Has anybody tried to use the hydrodynamic model to calibrate the RR model?
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Dear Fredrick :
The hydrodynamic model could be useful. For example, with the hydrodynamic model you can calibrate the stream routing of the reaches defined in the hydrologic model (for example by calibrating the X and K of Muskingum method).
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Hai everyone, I am working of SWAT CUP for my validation and calibration. After doing first calibration , i got the value of NS equals -0.17. Then when i am again doing my calibration again to get the exact value of NS  , i am facing an issue that "the application has requested the run time to terminate in an unusual way ". i attached the screenshot of the problem what i am facing now.  Can anyone give a proper solution for this , so that i can move further. 
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My dear your program got a divergence. this is occurred when the errors summation is exaggerated, correspondingly the program terminates himself. This occasionally is occurred when the boundary conditions are not adjusted.
Please dear colleague give a correct value for every node at the boundary of your model domain and rerun the program again. if you do so, surely, the problem will be diminished.
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I recently downloaded the shapefile (ArcGIS) for Nile River Basin but I failed to download for Blue Nile Basin.
Thank you very much in advance.
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Hi
In the following link you can download all shape files and raster datasets for your study area...
In addition, by using ALOS-30m DEM and ArcHydro in GIS you can extract streams network for your location. I attached a file that describes How can you download high resolution DEMs, such as ALOS-30m, SRTM-30m and SRTM-90m...
I hope that works
the best
Azizian
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Need to understand the long term changes in the release from upstream storages to the intensively cultivated delta.
Normally flows are from July to Feb months only, over the years flow has reduced to Aug to Jan.
flow data is available for a network of 17 gauging stations in delta. how it can be studied ?
any suggested literature ?
Can i do the analysis in Excel ? if not please suggest some software ?
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There may be other considerations to include, and check for data availability or possible for development. Changes in rainfall during period of analysis? Changes in land use -- imperveous surfaces increase runoff peaks, reduce base flow. Changes in vegetation type such as pine trees in my vicinity can have ET of 30 inches, hardwoods 20 inches, grasslands 10 inches. Conversion to some species can exert substantial transpiration demand, enough to lower water tables and cause streamflow to decline. Also are there new or increased water uses in watershed, irrigation, wells, demand for water has increased from people, crops, industry, etc. Are gauged streams showing decline or just some of them. Are streams incising or adjusting to change (eroding, degrading, gullying, ditching or canals for drainage, drainage of wetlands). Are upstream releases of stored waters being changed for some reason? Is there increasing water management, storage or retention in dams, ponds? If there are no rainfall, land use, water use, water management or use, stream morphology or other changes, the problem becomes more difficult. It may be a combination of several factors such as those mentioned, producing this change.
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Hi there,
Scientific efforts in post-fire hydro-geomorphology seem to agree on the dominating importance of the hydro-climatic regime (i.e. precipitation type and timing) on the response of a watershed after a fire. Although variability exists according to scale, fire severity, or soil nature, it appears that post-fire heavy rain or snowmelt can be associated with higher runoff and erosion and eventually higher water and sediment yield.
However, I'm wondering how much topographical settings of a watershed, or of the burned area, can also act as a control of post-fire hydrogeomorphic response, i.e. runoff and erosion? By topographical settings, I mean elevation, ruggedness, slope steepness, curvature, and length, aspect, shape of the watershed or of the burned area...or any metric you could think of to describe a terrain.
To my knowledge, it is something that has hardly been addressed, and only a few papers seem to mention this (I'd be willing to read any reference you may share with me). It also seems that papers focusing on post-fire changes in water or sediment yield, or debris flow, tend to focus on locations displaying a certain level of topographical complexity.
I guess it draws 2 other questions, rather provocative, beside my introductory one:
- Is post-fire hydro-geomorphology "biased" toward complex terrains, especially steeper terrains, because a response is more likely according to general runoff and erosion processes?
- Can we generalize current scientific knowledge and argue that complex terrains, especially those displaying steep slopes, are more likely to experience greater post-fire changes in their hydrogeomorphic regime?
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Good question: macro. I'm not interested here in hillslope processes, but rather in their addition (or product) and how it translates into potential downstream effects that can be potentially problematic in terms of water resource management.
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Dear Expert
I have tried to simulate the hourly rainfall runoff events, peaks are matching but after peak the discharge at which it has to recede is not as expected as seen in the attached file.
Can you please advice me the tuning parameters for that in HEC HMS.
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Dear Vikram,
In HEC-HMS five methods are included to represent recession/ baseflow as contribution to streamflow. These methods vary from the linear reservoir method to the non-linear Boussinesq method. Depending on the method you are using one or more parameters can be calibrated. For instance for the exponential recession method that will be one parameter k: the exponential decay constant.
Regards,
Martijn
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i am working on modeling rainfall-runoff and initial soil moisture is an important data , is there any formula to calculate the initial soil moisture ?  using for example the API or simple inputs ?
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how to measure initial moisture content of plants?
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The data that I have collected came from height gauging station which has an acquisition interval of 10 minutes and a weather station that records every 15 minutes. The site where the gauging station is located has an established rating thus I can derive stream discharge.
I am trying to create a unit hydrograph of storm and heavy rainfall events using these data sets. I have tried using the method stated from the link attached. But I am not sure if the results I have arrived at is satisfactory.
If possible, do you know any method that I could use  to create a unit hydrograph? If so, what are the details of this method (procedure, etc.)?
Thanks in advance!
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With an area of 377 ha and a 15 minute resolution, it is likely that you will not be resolving the peak. Therefore the method I described should be applicable. Note that the time to peak flow will depend on other factors (e.g. topography), I would recommend using a cross correlation analysis (e.g.
to see what the average streamflow response to rainfall would be. This is also available in hydromad (deconvolution.uh).
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I would like to know if it is possible to convert the duration of a unit hydrograph.
For example, I have a unit hydrograph of a storm event that lasted for about 50 hours with a peak discharge after 3 hours. How can I convert this 50-hour hydrograph into a 4-hour duration with its peak discharge being reached at around the 30-minute to 1-hour mark? Has anyone been in a similar situation?
Thank you in advance!
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Yes, Minjiao is right. S-curves is the method. See for example this video: https://www.youtube.com/watch?v=wSvFrX48JOo . The method is explained there very nice.
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Which method do you recommend for estimating monthly and annual runoff data when you have monthly and annual inflows in million gallons, monthly and annual precipitation and temperature data as available data
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You can use either time series analysis or Artificial neural networks with wavelet and SVM techniques
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if you have soil moisture storage at depth (10cm), precipitation, infiltration and runoff value. you can calculate evapotranspiration for catchment?
do you agree with this procedure.
or this procedure is wrong?!!!
 >
1.     Infiltration rate during rainfall event expressed by runoff subtraction from rainfall event according to (Butterworth et al, 1999).
If= P-R .......... (1)
2.     The mass balance for infiltration may be expressed by the change in storage over a given period of time, where ∆SMsat-pre equals the difference between the inflow rate infiltration If in (∆t), and outflow rate infiltration, If out (∆t) by TRENT UNIVERSITY STAFF, so  If out (∆t) expressed in follow equation:
If out (∆t) = If in (∆t) - ∆SMsat-pre …………. (2)
Where:
If out (∆t) = outflow rate infiltration (mm/day)
If in (∆t) = inflow rate infiltration (mm/day)
∆SMpre-sat = difference between soil moisture content pre rainfall event and during rainfall event at saturation condition (mm).
3-The hydrologic processes in both catchments model include infiltration, runoff, soil evaporation, plant transpiration, and deep drainage. From the previous steps, the outflow infiltration considered as a deep percolation, so we can calculate soil catchment evaporation during 24 hr by root zone water balance equation (Lu Zhang et al., 2002):
Epan = (P + θSMpre.) – (Dp + Q + θSMaft.24hr) ………. (3)
Where:
Epan = Soil catchment evaporation (mm/hr).
P = rainfall event (mm/hr).
θSMpre. = Soil moisture content before rainfall event (mm/hr).
Dp = Deep percolation   (mm/hr).
Q = runoff event (mm/hr).
θSMaft.24hr. = Soil moisture content after 24 hr from rainfall event (mm/hr).
4.     Allen et al. (1998) equation used to calculated daily potential evapotranspiration used daily reference soil evaporation corrected by pan coefficient factor (0.65 – 0.70) related to region, as follow:
ETo = Kpan × Epan ……………. (4)
Where:
ETo = reference evapotranspiration (mm/day).
Kpan = pan coefficient factor (0.65 – 0.70).
Epan = pan evaporation (mm/day).
5. 
after them by water balance equation we calculate ground water recharge ?!
  (P) = (Q + ET ± ∆GW ± ∆SM) .
Where:
P = Precipitation rate in (mm).
Q = Stream flow (mm/sec).
ET = Evapotranspiration rate (mm).
∆GW = Ground water storage changes in (mm).
∆SM = Change in soil moisture content (mm).
Sarbast I. Abdi
thanks
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Using the water balance (or budget) approach to build conceptual models is very common in hydrology.
However, I would recommend that you consider the 'linked linear reservoirs' method to write down the model algorithm. For your example, a three reservoir approach - upper, middle and lower reservoir will be appropriate. Starting with the upper reservoir, consider all inputs, outputs and storage change for it. Next, the output from the upper reservoir becomes input to the middle reservoir and will have its own outputs and storage changes. This process may be continued for any number of cascading reservoirs and the model algorithm may be written down. This approach will eliminate the possibility of double accounting for inputs and outputs.
For instance, I believe in your algorithm, precipitation input is appearing in both the soil zone as well as the groundwater zone which is incorrect.
Hope this helps. Good Luck!
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Dear Expert
I would like to know, is it feasible to find out the trend in daily stream flow of very short duration (2 years) to understand the hydrological process? What are its applicability? Any research paper related to this if available then can you please share it.  
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I guess the answer is: not! For trend analisys you need very long time series, i.e. Demetris Kuotsoyanis recomends time series of hundreds years. Nevertheless papers with short time series (40 years) also are published (see attached).
For your very short time series I can recommend to find sincronized, with yours, larger time series and perform the trend analisys with these series and then try to transfer your conclusions to the short ones.
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Our study focuses on the impacts of grazing on hydrological processes, mainly surface runoff, evapotranspiration, and soil loss. We study different animals (with soft-padded feet and hooves) and different grazing intensities, and focus on mountainous areas in Peru. We found empirical evidence in many regions of the world, but not comprehensive review that could support a simple modeling approach.Thanks in advance!
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Since you are here in California, you can see the massive hydrological changes in the Sierra foothills and the upper Sacramento River valley like around the town of Weed, or in the BLM lands north of Reno in the former wetland areas.  
By removing the perennial grasses, the annuals have been soil nutrient and soil organic matter miners, so large parts of the arid West that have been grazed for a period of time, are now nutrient and organic-matter starved.  
Soil has been starved by the cows and sheep to the point, that the nutrient levels are below levels needed by native seedlings to survive.  See pictures at http://www.ecoseeds.com/good.example.html, on the left is the flat with soil only and no nutrients added--the seeds sprouted and died of starvation.
For the acres of grasslands that I am currently restoring from Los Altos Hills to Capay Valley, we have to POUR the nutrients back into the soil, that have been removed by grazing, and also add back organic matter.  On one ranch, we have to add one ton of fertilizer per acre, mostly the calcium that was removed by the dairy operation in the milk that was produced there.
Until you rebuild a grassland ecosystem with diversity from scratch, you do not have a clue on what has been taken away by the cows, and how much you must put back.
Sincerely,  Craig Carlton Dremann
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In my site, ground water table is very deep (>50 m), and the primary water source for plants is from soil water recharged by precipitation. Now I have daily soil moisture observations within the 0-280 cm, and I want to estimate plant water uptake profile by using these observations. First, soil moisture in the 0-10 cm was kicked out because its changes are dominated by soil evaporation. Next, I computed daily changes (δi) of soil moisture in the 20-280 cm (at eight depth intervals). Negative δi values suggest plant water uptake occurs, and positive δi values mean soil water is recharged by rainfall. Is it reasonable in this manner?  Thanks in advance for any help.  
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Gao Xiaodong nihao,
While my work focus is on pasture plants, By using frequent observations of soil water content at discrete layers within the 0-200 cm profile, we have been able to interpret both effective root depth and water uptake by plants.  
As others have indicated earlier, the degree of ground cover present will influence the partitioning of E and T fluxes on a daily basis.
See the attached papers for some examples.
Cheers
Sean
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Hi All, I am working in i-Tree Hydro model which depicts the change in runoff due to change in tree and other land cover. After simulating the model, the results show that the Baseflow, pervious and impervious flows also have been reduced. Whereas, the baseflow should have been increased with a decrease in both other flows. The input parameters are percentage of tree, shrub, impervious and water cover and evergreen tree and shrub cover and the meteorological and evapotranspiration data. Please suggest some measures or change in percentage of parameters so as to get a higher baseflow.
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 Bhavana, Are you taking ground water component also in the model? In an area where ground water is over-exploited, baseflow ought to be minimal.  
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how important is snow interception by plant for central Himalayas. Any reference articles.
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It is an important component of snow hydrology as it influences accretion and melt process. Most watershed hydrological models can simulate this process at regional scale using land cover and the threshold temperature for snow as precipitation. 
Here are some related papers:
Brown, Brown, M. E., Racoviteanu, A. E., Tarboton, D. G., Gupta, A. S., Nigro, J., Policelli, F., ... & Hummel, P. (2014). An integrated modeling system for estimating glacier and snow melt driven streamflow from remote sensing and earth system data products in the Himalayas. Journal of Hydrology, 519, 1859-1869.
Li, H. O. N. G., Beldring, S., Xu, C. Y., & Jain, S. K. (2014). Modelling runoff and its components in Himalayan basins. 7th Global FRIEND-Water, Montpellier, France.
Verdhen, A., & Prasad, T. (1993). Snowmelt runoff simulation models and their suitability in Himalayan conditions. IAHS Publications-Publications of the International Association of Hydrological Sciences, 218, 239-248.
Nepal, S., Krause, P., Flügel, W. A., Fink, M., & Fischer, C. (2014). Understanding the hydrological system dynamics of a glaciated alpine catchment in the Himalayan region using the J2000 hydrological model. Hydrological Processes, 28(3), 1329-1344.
Hope this helps.
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I have completed the simulation through the SWAT model. However, as I don't have the measured flow data, I don't know the accuracy of model output, and I can't adjust the parameter based by measured data, which could improve the model output.
A professor told me that an uncalibrated, or limited calibrated model is still a useful management tool. In fact, he believes SWAT was developed in part to evaluate ungauged watersheds.  
However, I believe that it is necessary to verify the accuracy of model output and adjust the parameter to improve the model output through comparing the simulated flow data and measured flow data.
I can't continue this work now, what should I do now? Can I apply the simulated data without verifying?
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I also have a question, somehow like above!
I have calibrated a watershed with SWAT, and want to calibrate the nutrient loads, I have data for that but the flow is also needed.
Is there any way to use nutrient ex: NO3 (mg/lt) for calibration that needs kg/month?
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Is there any other model more accurate than MODFLOW?
I think MODFLOW only simulates consumptive use of irrigation water, not the returned irrigated water.  In other words, the  effects of pumped water being returned directly to the immediate aquifer are ignored in MODFLOW. 
Also how accurate MODFLOW is in simulating interception by crops, to estimate the water balance in that area. Especially if i want to test different scenarios such as what will happen to water balance (especially ground water table), with landuse change 
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Looks like you need to interface with a surface model to accurately model the return flow nd drawdowns from withdrawal. Have you tried couple models like https://water.usgs.gov/ogw/gsflow/ or SWAT-MODFLOW at http://swat.tamu.edu/software/swat-modflow/
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Dear friends I am working on water balance in a watershed. Assume that water balance equation is as following:
P-ET-In-Int-R=0
In which P is precipitation, ET is evapotranspiration, In is infiltration, Int is interception and R is surface ruoff. Rainfall interception by vegetation cover is calculated using remote sensing techniques. Now, I wonder if I should eliminate all calculated interception from the water balance. As we know a proportion of interception becomes evaporated and the other part becomes infiltrated.
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If your primary aim is to quantify watershed budget, try to test your calculations with monitored values. For example, text your SEBAL ET calculation with other field observations. This way you can validate your calculations. SEBAL method uses energy fluxes in calculating ET, so may not apportion to individual pathways. Intercepted water could also be in the vegetative matter so you can still consider it but use the ET from SEBAl appropriately with additional field observations of individual methods.
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My area of interest is small rural catchment of 40 km², located in the sahelian climat (<600 mm yearly rainfall). In the past years (~1970-19990) a large portion of the watershed was covered with vegetation. Due to the population increase, and a higher demand in food, the cultivated portion of the watershed grew quickly. Due to anthropic stress and very poor land management and land conservation practices, more than 50% of the watershed is now degraded (bare soil) with soil crusts and sealing as described by Casenave and Valentin (see provided links below). As such, those specific soil surface characteristics affect runoff production, increasing discharges even though the total amount of annual rain tends to decrease.
I am interested in modeling runoff and sediment to assess erosion. In am interested in the spatial distribution of runoff and erosion rates. SWAT seems to be a good candidate for my specific study case. But I would like to consider the fact that throught the years, specific land units representing homegeneous soil units with specific soil surface characteristics evolve in terms of shape, size, location in the watershed. Those informations will be derived from a series of Landsat Images of the watershed on the 1979-2016 period. Is there any way to couple such needs with SWAT ? Or can ayone suggest a better approach ?
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I would say that in did SWAT is a good candidate, but not necesarily the best and certainly not the only one. Look at the following publication for an overview of about 50 (yes, 50 such modells).
Being that you are interested on looking into the dynamics (you mention: e.g. specific soil surface characteristics evolve in terms of shape, size, location in the watershed) I would suggest you go for a more physically based approach. Note that the EROSION module of SWAT with the USLE equation and its derivates MUSLE, RUSLE is purely empirical.
You may also want to look at so called "landscape evolution models" like CHILD and CAESAR. Such models are usually developed for very large time scales in mind (thousands of years) but the concept is precisely that of a dynamic lanscape as the one you are interested in. In the case of CAESAR it is supossed to be applicable at shorter time scales (days - years), so a look into them may be worth effort.
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I'm interested to analyse the contribution of different sources such as snow/glaciers, GW, rainfall, etc to the total flow of a river. Which model would be the best fit particularly to the Himalayan region? Please suggest
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Jeeban ji, please try J2000 (http://jams.uni-jena.de), I can provide running version with test data for Dudh Koshi. it is easy to set up (some online tools available for HRU delineation, simple user friendly model, inbuilt optimization, sensitivity and uncertainty tool, can be run in server as well as desktop). It can separate glacier melt (seasonal snowmelt, icemelt and rain runoff from glacier area), snowmelt out side of glacier, surface flow, ground water flow etc. you can also distinguish infiltration, percolation, interception, ET etc. Based on data availablity, you are free to choose complex processes (such as Penman Monteith) or simple (ET driven by temperature based method, Hargreves Salami). Good luck. let me know if you need more information.
Hope this helps.
Santosh
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How to estimate deep percolation from rainfall and runoff data during individual rainfall event, were the soil moisture content before and current event are available?
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Conventionally, it is assumed that deep percolation (or more appropriately drainage below the depth of interest) is assumed to take place only when soil moisture is greater than the 'field capacity' of the soil profile. Field capacity - defined as the moisture content at which gravity drainage ceases, may be determined from the soil water retention curve as the moisture content at 10 -33 kPa soil water tension. Alternatively, it may be estimated from standard values for a given soil class as per the USDA triangle. 
Then as suggested by Prof. Randhir, a simple water balance may be calculated by accounting for rainfall, irrigation, runoff, evapotranspiration and profile soil moisture may be calculated. If this calculated soil moisture is greater than field capacity, the difference between them may be assumed to represent drainage. 
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If I have spatial polygons describing thousands of river catchments in a large region, what is the smartest way to define a relational system between catchments? I'm familiar with concepts from computer science such as linked lists and tree directories. I don't want to re-invent the wheel. Has anyone come up with the definitive method to store the relationship between catchments so that, when needed, it's possible to answer questions such as:
> which catchments are within this catchment;
> which catchment does this catchment drain into;
> what is the chain of catchments upstream and downstream of this one.
I think it's an interesting problem probably with multiple solutions. I would appreciate any thoughts/discussion.
Thanks. 
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On my researchgate list in ~2005, we used the USGS/NRCS numbering system to number the hydrologic units in SC, USA from region, subregion, basin, subbasin, watershed, subwatershed with each category having two digits.  
Separately, a system to order channels and streams and number them by stream from headwaters to watershed was used at barious times.  I believe I uploaded the Chattooga River Water Quality report that included some of this description.  We called these Drainage Basin Response Units (DBRUs), and in an EIS I uploaded in 2013, it shows how I used this information to analyze a large project, and its estimated effects to sediment and water yield from timber management, temporary roads, prescribed burning, etc. The information was all spatially analyzed in GIS using RUSLE approach for estimating erosion.  If you cannot find, let me know and I will send from my files.
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Modelers can make any thing possible, so answer could be 'no'. But from real physics point of view answer could be 'yes'. I am eagre to know ways to tackle the situation if answer is 'yes'.
some thing is better than nothing’ this statement could be more true in routine way or issues, but may be not equally factual in natural science like hydrology. I would like to put a hypothetical scenario - when for a given catchment (say 2000 ha) we have continuous river flow data at the interval of 6 hrs, but the available rainfall data is only at 24 hr time step i.e. daily value. River has continuous flows, giving hydrographs of broader bases say 15 to 20 days atleast. For generating runoff prediction models, this partially gauged catchment is as good as an ungauged catchment ( in want of accurate rain input data). How to deal such situation ? What are the innovative ways to move ahead for coming over to such deficit at one end and carving out some regional predictive models for totally ungauged locations on other hand, eliminating uncertainties of predictions/simulations in accordance to prevailing physics/phyisiographical configurations of catchments.        
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Thanks William
Very nice penetrating and accurate kind of reaction. each and evry bit you wrote is correct and I 100% agree with your views and analysis. Stream flow marks are the best and most reliable data for hydrology, even surpassing modern days sensor based or other hi-tech dynamic modes of gauging flow levels either in stream or over some kind of hydraulic control structure (weir/flume etc). For any kind of hydrologic signature from any natural catchment, it is the peak flow rates which matters a most , and this peak stage of flow has direct connectivity with peak stage of flow in a channel at any given point of time....and yes..as you have very rightly said  the  peak flow marks on sides of the channel in different looks ( may be a sediment layer marks, or vegetation adherence lines or any scour or cut line in regular manner along side walls etc) are the best indicator to work out the peak stage of flow and in turn the peak discharge rates..Very nice example 'Luna Leopold' and i have generated eagerness to sail across it some time. I too have many such attempts in real ground situations, where in degraded un-accessible  forest catchments, some simplistic locally fabricated crest gauges were devised and installed putting / reusing some waste pipes and erecting them in centre / bed of channels at appropriate location and then putting some kind of light floating grounded substances like saw dust or charcoal powder at every morning and then placing a wooden stick or scale inside pipe, and visiting that pipe daily in morning by taking out the wooden scale and observing the layer of saw dust or charcoal particles whatever used ..a circular layer circumferential was easily visualized at each visit, and setting its height in accordance to channel bed, gave a good estimation of peak flow stages and in turn the peak discharge rates too. 
But still,the core theme or expectation from learned friends here, is that " if we like to simulate full hydro-graph " under given situation ( rainfall @ 24 hrs time step; discharge @ 6 hr time step) what could be the simplistic and alternative ways and options  , and which options to be used to make use of such situation where neither it is a truly gauged situation nor a truly ungauged situation. Our intention is to predict full hydrograph under varied rainfall input conditions and input rainfall is available only at 24 hours time step. while we wish to conduct calibration and validation for discharge hydrographs having time steps less than 24 hrs ( may be 3 or 6 hrs).  
for tropical situation like India, even when the base of hydrographs is in days ( as in this case), the exact duration of input rainfall (if taken as 24 hours) is full of errors/uncertainties, as exact rain or storms in real situation which are responsible to produce overland flows/channel flows are hardly of few hours (not 24 hrs) and it has great impact on shape, volume and overall hydrograph function. so at last  it could be termed a work on an ungauged catchment only   , even tough we have some data (partially guaged)..  How to harness the potential benefits of partial observations or how to transform time scales to make them identical? ( conversion of 24 hour rain fall data into 6 hour rainfall values; or taking 6 hours discharge date into a 24 hour time step value- both cases have errors/high uncertainties which are not wise to get recommended for predictions in nearby ungauged catchments ..whatever the kind and model we adopt....
Once again thanks for your nice words and giving time on mine question..
Regards
Gaur
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I have calculated the uncertainty in the developed rating curve (stage discharge relationship). Now the different catchment have different uncertainty level, do we correlate it with any hydrological phenomenon or what will be the reason for that?
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i agree with Rafael Anleu
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I used a rainfall-runoff model to study catchment hydrology and got time-to-peak [hour], peak discharge [cms], and hydrograph duration [hour] for several catchments. Is it possible to construct hydrographs using these three inputs?
I assume some optimization methods are required to create specific shapes of hydrographs...Any ideas which curve should I use and how to create it?
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i want to know about rainfall-runoff method that can be convert rainfall to runoff discharge specify for small,steep catchment area.
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It is better to use any method related to Distributed Hydrology and GIS. While for the large catchments,  it better to use lumped methods.
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The runoff coefficient for a watershed gives a fair idea about the input-response relationship for the system. The major factors that affect the rainfall-runoff relationship can be broadly categorized into Physiographical and Climatological factors. The physiographical factors involve land use land cover, soil type, underlying geology, stream density, elevation, stream slope, land slope, etc.While the climatological factors include rainfall amount, rainfall intensity, antecedent soil moisture, evapotranspiration, etc. The effect of physiographical factors can easily be ascertained but how to relate the climatic parameters such as effect of evapotranspiration rates on runoff coefficient. Are there any metrics or statistical measures to analyze them?
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Hi Priyank,
The runoff coefficient is the ratio of discharge (Q) and precipitation (P): Q/P. If you consider a long time period where the initial water storage is the same as the water storage (S) at the end of the period the water balance of a catchment is dS/dt = P-Q-ET where dS is the change in storage, t is time and ET is evapotranspiration. Since dS/dt = 0, Q = P-ET and the runoff coefficient becomes (P-ET)/P or 1 - ET/P showing directly the influence of ET on the runoff coefficient.
The effect of other climatological factors such as precipitation intensity, precipitation amount, dry spell length etc. can be investigated using a hydrological model which complexity will depend on data availability, aim of the modelling and spatial and temporal variability of relevant hydrological processes.
Regards,
Martijn
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I am using ArcHydro and HEC-GeoHMS extension of GIS for HEC-HMS. Facing the issue while determining the River Slope using HEC-GeoHMS. Error is attached herewith. Kindly guide me how to further proceed?
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I am facing same problem as mentioned in question. I am stuck at river slope calculation using HEC-GeoHMS extension.
I also tried Shahzad Sultan advice but still have problem.
Any one have solution please Share it.
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Dear Firoz,
here is another source with the proceedings of the International Conference on Water Resources of Arid and Semi-Arid Regions of Africa, which took place in 2004:
Also, check out the extensive UNDP material about IWRM, you will find a lot of material on arid regions in there as these tend to be the crucial catchments:
All the best,
Michael
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Conservation of mass and momentum ' the big theory always remains with us for generations. According to it total quantum of water on globe will be same, even to the accuracy of a single drop. But its location and form will change in most unpredictable manner with infinite uncertainties, which will remain exactly equal to the level of unpredictable & uncertain intrusion we people are doing or giving to nature and whole natural system.
My question reflects a virtual scenario, assuming a when not a single drop in ground, all is either on surface or in atmosphere? What we must do and how we prepare ourself for this, which in my opinion can never be said 100% hypothetical question ?
I love to have comments of great experts here. Also I like to supplement that it is based on a quote from one of the famous NASA scientist ..who is going to speak and debate on it...soon
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Thanks  Jan
it was just a philosophical and to a great extent hypothetical issue....just for a discussion and raising food for thought...to promote thinking on optimum conjunctive use of surface and ground water..
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Hello.
I'm using a water level logger named 'HOBO U20'.
According to its manual, the Logger records absolute pressure, which
is later converted to water level readings by the software. Normally, atmospheric pressure is 100 kPa at sea level, but changes with weather and altitude. Because my study site is in the middle of the mountain area, HOBO U20 Water Level Logger can be used as a barometric reference to compensate for barometric pressure changes.
I use two loggers and one is set in the stream to collect water level data and the other is set on the ground as a barometric reference.
I would like to know the principle to deduce the water level from both pressure data. Is there the relationship like some mathematical formula ? 
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I was wondering if anyone knows where I can find Haiti streamflow data because I will be working on it soon it seems to me it is not available at 
it seems to me it is not available on  their website in this link
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Availability of rainfall intensity data at micro scale is a big constraint in attempting rainfall-runoff modeling. often we have daily rainfall data . Is it possible to use that time series , to synthetically derive hourly rainfall values . I hope to get educated and invite supportive stuff if any of us have ? 
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RMC (Random Multiplicative Cascade) model is also an option to disaggregated daily rainfall into hourly rainfall. You can google about it e.g.
I have tested this approach in some of the stations in South India. This approach work reasonable to get the reasonable estimate of distribution at hourly scale.
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I am looking for the value of the HDI, that it would be possible to separate USGS gauges to non-urbanized, semi-urbanized and urbanized watersheds based on that. As I am working in the ArcGIS, I need quantitative values for this index.
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Using watershed metrics like Effective Impervious Area has been successfully used to evaluate stream impairment. This might work well to classify urban, and suburban areas rather than general land cover metrics. Given your background in GIS, I recommend using EIA or similar classifications of the watershed land to develop thresholds. This literature is well developed in past decade. One threshold you could use is 10% EIA that has shown to have a shift in nature of impacts from rural to suburban conditions. Indices like HDI could help but using it to classify the type of land use impact on hydrograph is not straightforward. 
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I research effects of riparian zone on water quality. Have you any idea about this issue?
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Dear Robert L. Vadas thank you so much for your contribution
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I have just one station in the outlet and have monthly rainfall too.
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Basically if your outlet station records water level on stream per time, and you have stage (level) relationship to discharge in cubic meters per second, calculate the flow by time unit, and add it up for each month, and your total will be in cubic meters for each month.  Your watershed will have a size in square kilometers.  Each sq kilometer is 1 million sq meters.  Divide the monthly cubic meters by the watershed area in square meters, and you will get meters of water yield averaged over the watershed.  You may prefer to report that in cm or mm, and can make the conversion to compare with rain data from your station.  Most of this can easily be done with an excel spreadsheet, and there are various ways to report results on a daily, monthly or annual basis. 
If this is not what you were wanting, perhaps I misunderstood and you may clarify. 
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I am looking for ISO 7066-1-1989, Its basically for Assessment of uncertainty in calibration and use of flow measurement devices -Linear calibration relationships. Please share it if some one have. I will be thankful for this. 
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I am using salt dilution method for discharge measurement in small strems, too. Constant injection can do better method (versus single) 
We used as reference measurement of the hydrometric propeller or doppler. 
Our results were no more be within 10%
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I have worked out the sediment loss from two micro watersheds. I am not sure whether the obtained sediment loss values can be categorised as 'within permissible limit'. Pleas guide.
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Oliveira et al. (2008) and Derpsch et al. (1986) obtained mean values for soil loss tolerance in Oxisols of 10.64 and 12 t ha-1 y-1respectively.
Derpsch, R., Sidiras, N., Roth, C.H., 1986. Results of studies made from 1977 to 1984 control erosion by cover crops and no-tillage techniques in Paraná, Brazil. Soil Till. Res. 8, 253–263.
Oliveira, F.P., Santos, D., Silva, I.F., Silva, M.L.N., 2008. Tolerance for soil loss by
erosion in Paraíba State. Rev. Bio. Ci. da Terra 8 (2), 60–71 (in Portuguese).
Observe that these values are for Oxisols. Different classes of soils will have diverse values. Soil conservation is a complex issue and sediment yield must take into account the watershed as a whole. Geomorphology research is fundamental. 
In my research in the mountain region of Rio de Janeiro, sediment yield was            14.8 t ha-1 in the period of March 2008 to January 2009 in an Oxisol.
Nacinovic, M.G.G., Mahler, C.F., Avelar, A.S., 2014. Soil erosion as a function of different agricultural land use in Rio de Janeiro. Soil Till. Res. 144, 164-173.
 Mendes et al. (2011), in a study with erosion plots, observed a sediment yield of  30 t ha-1y-1 in an olericulture parcel in a mountain area of Rio de Janeiro state.
Mendes, C.A.R., Mahler, C.F., Andrade, A.G., 2011. Superficial erosion in a yellow
argisol under perennial crop and fallow forest in a mountainous area. R. Bras. Ci.
Solo 35, 1387–1396 (in Portuguese).
Four thousand lives were lost in floods and landslides in 2011 in the mountain region of Rio de Janeiro State - in particular in the cities of Teresópolis and Nova Friburgo. Erosion is causing siltation of the major rivers in this region which potentializes floods. This fact is not permissible!
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I have only one hydrometric station in the output point of the watershed. but i need a map for all the watershed. How can I access to the maps of my variables or related variables.
Thanks
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Dear Zeinab Hazbavi,
I agree with Maria J. Polo. A hydrological model can be used to generate runoff in a distributed way. You can use SWAT (Soil and Water Assessment Tool) model that will automatically delineate the basin based on the input Digital Elevation Model and divide it into various sub-basins. You can obtain both streamflow as well as sediment yield for your basin area. This is a very widely applied model allover the world. The model gives sub-basin wise analysis and so, it will be possible to generate streamflow and sediment yield based on sub-basins, hence, map for whole watershed can be obtained.
I hope this helps you.
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Our research involves observing the contribution of trees in lessening floods along a watershed area through rainfall interception. To measure rainfall interception in a 900 sq.m area, we plan to use throughfall collectors and stemflow collars. How many throughfall collectors would be ideal to measure rainfall interception in an area this wide and what would be the most effective way to position them in order to obtain accurate results?
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Sent extended message to Tanya Valdez (also Manila) that you might look over.  Spatially, throughfall can be highly variable, so this creates a concern for accuracy with tree and plant species, density, etc.  And under some conditions, moisture can condense on trees, without raining.  But in sampling your area, I would set up a grid of the inexpensive plastic wedge gauges and decide how many I would be willing to install and read.  Also you would want one or more standard raingauges, installed correctly.  One problem with the wedge gauges, is they may not hold enough rain-throughfall from local funneling of water off of a few banches, so you may need to look for something else.  I dont think you could oversample throughfall, but you may overinterpret your result if depending on 900 sq m plot to be representative.  If you installed 1 gauge every 3 meters, assuming 1.5 m buffer of edges, that would be 81 gauges.  If you did 5 m grid, with 2.5 m buffer, you have 25 gauges.  If you were able to cover the entire area with plastic, and funnel all water into storage or measurement gauge, your sampling of that area would be the most accurate, but certainly more difficult, and not necessarily representive of all areas.  
For storms that produce floods, the trees, soils, wetlands, etc., can only hold so much water, and your efforts if converted to measuring rainfall and runoff from small or moderate size catchments may be better suited to your ultimate question as to what actually runs off and what infiltrates or is delayed into reaching streams.  Forests often produce low runoff responses due to high infiltration in comparison to many other land uses.  Certainly there will be an element of interception to consider, but when talking its impact on floods, you will want to look especially at intense or extreme events.  In addition as compared to other land uses, trees often transpire more water, reducing soil moisture and water table which allow for a greater potential for added storage capacity in response to rainfall.  If you could compare water balance and flood peaks from forests to other land uses, forests would typically be the best land use to reduce floods.  But this is not just due to interception.  If this is too much to take on, if you have a hydrology section, perhaps a joint project would be more comprehensive and beneficial to both subjects.
There are many past studies addressing water yield in USA, many by US Forest Service scientists using experimental watersheds.  Some of these studies also probably collected infomation on throughfall.  In my response to Tina, I uploaded a paper you might like that pertains to your topic.
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Ideally this would be a 2-person raft for deploying instruments (e.g. CTD, LISST) off the side. I like the look of the Alpacka rafts but have never used one and don't know how stable they are, especially when trying to pull up an instrument from 50m depth. I'd rather not go into the drink. Any suggestions welcome!
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Thanks Denny - I definitely do remember our holey raft! I also bought an electric bear fence for this summer. Hopefully that'll keep them at bay!
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i am working on dssat  model v 4.6 for climate change studies for rice wheat crop but i am using the automatic irrigation option for irrigation which after simulation gives output effective irrigation less than the recommended for both the crops so i want to know how to increase it to the recommended. what is the reason that it is happining so i am also attaching the file. please have it in attachments
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