Watershed Management - Science topic

The leaching process duration can be estimated using the leaching requirement formula:

t = H/K

where:

- T is the leaching time,

- H is the leaching requirement (difference between initial and desired salt content), and

- K is the hydraulic conductivity.

SWAT is mainly preferred among the models asked in your list. The HEC_HMS model is usually selected for event-based modelings like simulating flood hydrographs or in the design of flood estimation. Since you are simulating for a continuous time period, SWAT is a better choice. It is a widely used model. One can even incorporate management and agricultural practices.

There are various challenges I faced in research and then as a hydrologist/watershed specialist working for the USForest Service. As with any country or land ownership/management, one must understand the pertinent laws, regulations, goals and intentions, such as Caring for the Land and Serving People. Watershed Management is not the only reseource that managers must consider, so it is best to prescribe or suggest measures with reason and meaning. Reading and interpreting the hydrological and watershed research, and then trying to apply it to the land and resources while still allowing a reasonable degree of activities, while keeping effects as erosion, sediment and water yield changes to acceptable levels is a challenge. For example, mass forest land clearing has been shown to produce high effects, but spacing the harvest areas out and not covering more than 25% of any area seemed to be a reasonable compromise as long as the conditions and streams were stable. Rapid reforestation was expected. Other challenges occur when there are landslides, severe erosion, gullies, road or fill failures, other interconnected land or water uses as mining, domestic drinking water, irrigation, wastes from industry or urban areas, structural designs to consider flooding, fish passage, etc. The list of items and the public or stakeholders involved can be complex and change from area, project, watershed or basin.

You might find a few software that purports to address watershed management, and it might be a helpful start. But depending on country, conditions, ownership, stakeholders, etc., watershed management expectations and plans could change. Most watershed scientists and managers are typically consultants, and not the final decision makers. So prescriptions and plans need to be well based in research, reason, field and resource conditions. Many activities that can affect watershed and water conditions have best management practices (BMPs) or soil and water conservation measures developed to fit conditions.

If you want to take the time to look through the papers and reports, etc. that I uploaded, you will find some examples of the types of issues and projects a watershed specialist might deal with. In my last few decades with the USFS, I lead the local development of automating the RUSLE so it could be applied to forest management estimation of effects of erosion, sediment and more recently water yield changes. The emphasis was the calculations were not real, but could be used to estimate differences in land use options or alternatives. I think I uploaded to Researchgate one of our environmental assessments concerning restoration (removal) efforts of mountain areas planted in error to loblolly pine. As remote sensing through aerial photos, and LiDAR coverage, and availability and digitation of soil maps, contour DEMs, land uses and cover types, geology, hydrologic boundaries, etc., these were instrumental in helping to make appropriate field, road and stream checks.

There are various books and papers addressing watershed management or some aspect. A good start at the University level would be taking a few suitable courses land and resource inventory and management including hydrology, soils, geology, vegetation, land uses, etc. Your country, landowners, resource agencies, and communities may have their own ideas or suggested direction. Basically all life to varying degrees depends on the soil, water and air. There is probably no cookbook on how to start, but after some literature review and inventory of conditions, one might proceed. One of our uploaded papers was on the Hydrologic Condition of Indian Creek. It’s not really an example of watershed management, but may give you some idea on some of the factors to assemble. Resource inventories and data assemblage often lead to storing data into a GIS format. How the watershed is managed can affect the water quantity and quality, which in turn can affect the types of resources and uses it can support. Various land uses and associated activities can also influence water, so identifying some best practices and if needed regulations can be helpful to achieve overriding societal goals. But it is not unusual to find conditions of past historical land and resource abuse where watershed conditions are poor or less than desired. Reestablishing acceptable watershed conditions is sometimes difficult and costly to achieve. That is why developing a watershed management plan can be very important to identify current conditions and help determine if protection, constrained management (rules, regulations, BMPs, etc.) and/or improvement measures are needed. As suggested by Dr. Singh, assembling stakeholders for involvement is preferable, but one should also consider in areas of critical water supply and a past history of water use and land ownership, one may need to work to diffuse issues with appropriate meeting management skills.

Thank you Marine Nalbandyan

Identifying the bioclimatic regime of the areas under threat to fires is one of the foremost requirements for an efficient forest fire management strategy. These days Google Earth Engine provides one of the fastest ways to prioritize vulnerable areas within the forests. Janaki Sandamali William F. Hansen and others have provided useful information regarding it.

Dear Dr. Douglas Nuttall

Thank you very much for the insightful description.

Regards

Gowhar Meraj

Good call...

Thank you, Brett Boisjolie, for discussing this issue. Since I live in a Himalayan region, we are still coping up to bring automated data loggers in our hydrological assessments. Usually, the systems we use are stand-alone systems that record data, which field workers manually pick up. However, in downstream areas wherein cellular networks are available, the data is continuously logged and sent to the admin while storing that in the cloud too...

Thanks

Nanco Dolman

From Ladakh, this is a very good example.

look for NASA GPM

all about integration

Make spatial extent

It's about watershed properties and management practice

look for NASA aqua and terra

Morpometric analysis

in which environment

look for GRACE

need agriculture economy

good question

no

Just calssify LULC with systematic approch

its one

Spatial anlysis

Look for spatial parameters and the groundwater settings

Best management practice includes all the hyperspatial aspects and socio-economic

long one I think

Check dams reduce erosion of the area around the highway. They can be designed also using EC 2 ON CONCRETE STRUCTURES.

Management of water resources

In Brazil, each state has regulations about which crops can be planted and where according to agroclimatic zoning principles (coffee examples attached).

They also have laws about amount of land to leave wild but in frontier regions these are often not respected.

have a look this important pdf attachment.

Interested

you can read in the files as text (if you dump them as such),

then you can extract shape descriptors, moments etc., and feed them as features to your neural network classifier.

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.

Hi dear N. Joshi

This old paper (from 1995) summarizes, refers and discusses most of the vegetation indices found in the literature. It presents different existing classifications of indices and proposes to group them in a new classification:

There is other newer reviews about vegetation index:

2017:

2014:

2009:

2006:

see too this research: https://www.researchgate.net/search.Search.html?type=researcher&query=review%20vegetation%20indices

Hugs. Luís P.

Dear Gebiaw - Good links on the topic. Best wishes

Thank you.

Dear Robert,

Thank you for your explanation. I agree with your view. But there is one thing which need to be paid attention. Generally we think that functional connectivity is depends on the structural connectivity but I think some sediment transport processes (such as Sediment Storage or Sediment Redistribution) are due to of inconsistency between structural and functional connectivity.

I would like to know what you and other readers think about this matter.

Best wishes,

Saeed

Hello Saeed,

You can think of 'structural' features as elements that exist in the landscape or environment, even when there is no runoff or sediment transport (i.e. during dry weather). They might include the location and dimensions of patches of bedrock outctop, or patches of plants, or gullies, rills, roads, bunds, etc. 'Functional' connectivity means how the connectivity actually operates when the system is transporting water and sediment. This would clearly depend on things like the length of time rain lasts, how intense the rain is, how wet the soil might already have been when rain began. Structural connectivity in general would only change relatively slowly, but the 'functional' connectivity could change from minute-to-minute or over hours.

Hope this helps,

best wishes

David

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

Hi Kehinde

Hope the following link and papers will be helpful for you.

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.

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. 

In issue in your research design is the selection of NPP as the independent variable and recovery as the dependent variable. How are you measuring the NPP (actual, potential) or are you intend to predict NPP? How do you define recovery? Pre-fire biomass, NPP or species (diversity)? Recovery in all three features is by definition fast in pyro-climaxes on the millennium time scale like the Mediterranean biomes (maquis; garigue, fynbos, savanna, steppe) and those on the century timescale (taiga, heath). Further you may consider your time scale.

An issue you may consider in less frequently burning biomes is the whether the pre-fire plant growth is N or P limited as N is removed from the system by fire.

Hi Alan

I'm not sure whether you are interested in doing household level surveys (although the tool can be adapted beyond that).  If you are, have a look at the tools and support systems for household surveys developed by the Computational Tools Team of the Development Research Group of the World Bank.

The computational tool is named the Computer Assisted Personal Interviewing (CAPI) tool for undertaking household surveys. CAPI tools are part of the World Bank Open Bank, Open Data, Open Knowledge initiative, which has developed analytical tools for applied research by bringing together specialists in high‐level programming, advanced econometrics, and geographic information systems to create appropriate data

gathering and analysis products/tools.

The programme covers a number of areas of support for research, viz.:

 Software for data collection

 Software for automated data analysis

 Software for data dissemination

 Tools for micro‐econometric analysis

The project to develop the CAPI tools was initiated in 2012 as a joint venture collaboration between the World Bank, the Bill & Melinda Gates Foundation, the Living Standards Measurement Study‐Integrated Surveys on Agriculture team and the Food and Agriculture Organization of the United Nations.

The tool allows an efficient household survey process that provides respondents the option of filling in their own questionnaire for privacy if required.  It also facilitates data analysis and consolidation to a central hub that allows updating of data in an uncomplicated and cost‐effective manner and a relatively simple 'in-house' tool for tracking changes from a baseline and for monitoring and evaluation progress.

Good luck

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. 

It was indeed nice to read apt comments by Dr.Hensen and Dr. Green. Here are some of the observations published in recent publications...

Recent research in forest hydrology points to the fact that the general assumption that more trees equal to more water is based upon our inaccurate understanding of the hydrological cycle in forest ecosystems.   This assumption has so far dominated most forest and water policy. In fact the forest ecosystem is the major user of water. With tree canopies, through interception of precipitation and evpotranspiration from foliage there is reduction in the groundwater and stream flow. Both natural and manmade forests use more water than most replacement land cover including the agriculture and grazing. This may be translated in the fact that even partial forest removal may result in the increase in the downstream water yields. Although there are some suggestions of the  removal of water-demanding forest cover as a means of preventing or mitigating droughts, especially in semi-arid regions. However, such a policy is been weighed against the consequent loss of the many other services and goods that forests supply. These include erosion control, improved water quality, carbon fixation, reduced salinization, recreation and aesthetic appeal, timber, fuelwood, other forest products, and biodiversity.

It is also well established that partial or complete removal of the tree cover accelerates water discharge, increasing the risk of flood during the rainy season and drought in the dry season. Although forest cover’s importance in regulating hydrological flows has often been overestimated, the impacts of forest cover removal are evident only at the micro-level and in association with short-duration and low intensity rainfall events (which tend to be the most frequent). As rainfall duration or intensity increases and the distance down the watershed and river basin becomes greater, other factors start to override or dwarf the effects experienced close to the deforested area. These factors include the size and morphometry of the basin, what happens in other tributary streams, the direction of the storm path and the intensity and duration of the storm

At the macro-scale, natural processes – rather than land management in the upper watershed – are responsible for flooding. Hence, although there are many good reasons for reforesting watersheds (e.g. reducing soil loss, keeping sediments out of streams, maintaining agricultural production, wildlife habitat), reducing flood risk control is certainly not one of them. Reforestation to prevent or reduce floods is effective at only a local scale of a few hundred hectares. Even on the local scale, much depends on the depth of the soil and the character of the precipitation event. Deep soils can store more water before they become saturated, and deep-rooted trees make the soil mantle more receptive for storing water from a new event. Antecedent rainfall and soil water storage have a great influence on the generation of runoff. Thus, for frequently occurring rainfall events of short duration or low intensity, forested soils may reduce or prevent flash floods locally. For the rarer prolonged or high-intensity storms, however, once the soil layer becomes saturated, water will run off, even where there is full, undisturbed forest cover. On shallow soils, especially steep ones, storage is much less and the watershed is more prone to flash floods; trees or other vegetation or land use can do little to stem the fast subsurface and overland flows.

A publication by FAO and the Center for International Forestry Research (FAO and CIFOR, 2005) has this to say: Although forests can play a certain role in delaying and reducing peak floodwater flows at local levels, scientific evidence clearly indicates that forests cannot stop catastrophic large-scale floods, commonly caused by severe meteorological events …. This in no way diminishes the need for proper management and conservation of upland forests. But it does point toward the critical need for integrated approaches in river-basin management that look beyond simplistic forest-based “solutions”.

Forests’ most significant contribution to the hydrological balance of watershed ecosystems is in maintaining high-quality water. This is achieved through minimizing soil erosion on site, reducing sediment in water bodies (wetlands, ponds and lakes, streams and rivers) and trapping/filtering other water pollutants in the forest litter and underwood. Good forest cover is the most effective land cover for keeping water as sediment-free as possible. Forest is certainly the best cover for drinking-water supply watersheds, because forestry activities involve no use of fertilizer, pesticide and fossil fuel, or outfalls from domestic sewage or industrial processes.

You might try the USGS Hydrologic unit code website

http://water.usgs.gov/GIS/huc.html 

My expertise is not GIS, but I use it alot.  From your question, I detect you may not have delineated a watershed boundary before.  I would suggest for anyone, even modeler, do it by hand the old fashioned way a few times.  I have done it by hand so many times, the boundaries on topographic maps are easy to pick up, and will give you appreciation of what flow accumulation modeling and boundary determination can and cannot do.  The dam is your hydrologic outlet (low point), and in delineating, you go from dam perpenducular to contours on both sides of the dam to the ridge, then follow the highest ridge that defines water flowing into or out of your watershed.  Your line will intersect top of ridge or mountain, continue through saddles between the highest points.  Doing this by hand may be slow at first, but it is an exercise for understanding.  Infrequently, you may find generally small mistakes in modeling boundaries, that may force a closer look at the stereo pairs as topographic maps are seldom perfect.  We have a researchgate paper from 2015 discussing improved delineation of coastal hydrologic units and streams.  I doubt it will address the GIS process detail you want, but may suggest how difficult this can be in relatively flat terrain with standard topographic map DEMs.  LiDAR DEMs are much better at defining detail -- also 2007 paper discusses other applications for using LiDAR in gully and channel delineation.

Correct, there is no set meander width and geologic conditions can restrict or enhance meander formation at any point along the valley floor. Valley width is probably an incorrect indicator, depending on the type of physical environment in which the stream resides. A steep gradient would restrict lateral migration and thus meandering, while a low gradient would promote a wide meander belt. However, a stream's valley floor (or floodplain) often represents its entire history to grade, thus there could be relict courses, overflow channels, etc. (see JPG). By rule a stream's meander belt is generally about 15 times the stream's width for moderately at-grade (or near-grade) water courses. One meander area in the attached JPG showing LiDAR data along an upland mature stream, however, has a width 20X that of the stream. If good LiDAR data is available for your study area, that would be best way to more accurately assess the meander width along the stream. This can be used along with historical maps and aerials to determine channel ages if you need to restrict the data to 80 years.

There is a good job.

FISRWG – Federal Interagency Stream Restoration Working Group. Stream Corridor Restoration: Principles, Processes, and Practices. Portland: Federal Interagency Stream Restoration Working Group (15 Federal agencies of the US Government). <http://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb1044574.pdf>.

Since water pollutants are chemical in nature and very minute too, their transfer through sediments will have a lot to do with porosity and drainage. Silt has a porosity of about 25% while clay has a porosity of about 30%, slightly more porous than silt. The higher the porosity the higher its water retention ability and the lower its drainage. It follows that silt has a higher drainage ability compared to clay and is likely to transfer  water pollutants more. As to which one of them being more important, it depends on your point of view. From my point of view, both are important since clay retains more pollutants while silt drains more pollutants.

Hello Saeed,

A detailed reply is not possible here but you may get your specific info from following link. 

Water losses specifically from surface could be reduced by mulching on barren surface and reducing the surface area of water ponds.

Subsurface water application may significantly reduce the evaporation losses. The most forgotten part is selection of plant species, we have seen plant recommended for waterlogged area with higher ET were planted in water scares areas :)

Cheers.

yes RUSLE, have capability for monthly soil loss but your all factor r not monthly changeable except R (rainfall) and C (for Vegitation).

And for monthly C you can estimate C from NDVI (monthly), which give u more changes (Monthly based) than the LULC (yearly changes) based,

also u can use this link

The ideas above are not bad.  I really don't know of the perfect answer.  Roehl  (1964 I think) estimated sediment delivery by watershed size for differing physiographic areas using dam efficiency as an indicator.  In general, his data supports smaller hydrologic units deliver more sediment per unit area than larger units.  The term subwatershed does not mean the he same to everyone, but by that term, I assume you are probably 10-40 thousand acres, maybe 4th to 6th order streams.  If you know or are aware of the Rosgen stream types, braided streams D type are efficient at retaining sediments, and other stream types such as G and F types are normally unstable, and more efficient at both eroding and delivering sediments.  Check out wildlandhydrology.com.  However if the ultimate goal is to reduce sediment, knowing streams or sections that are sediment sinks, aggrading, etc., those may be your friends, even though habitat for fish may be bad.  Streams that are degrading or actively widening to reach stability, those are important to find, along with major sediment sources along roads, landslides, gullies, etc.  Habitat for fish is not that great for these either.  The middle of the road are streams in balance as they have regular access to their floodplain at bankfull flow so their bank erosion is limited, and they are able to store some sediment during over bank flows during floods.  By identifying your most critical problems by stream reach or specific activity, such as roads or urban areas, you can more effectively target your objective.  I am not very familiar with SWAT, but it may include some of the land us and other factors that I would consider.I use RUSLE approach is that I have developed and adjusted for our specific circumstances, vicinity land uses, road types, etc. over the years.  Over the years, I have had mixed feelings about beavers, but I know in many areas of the USA, they were native species, and the early explorers suggest clear and clean waters.  I have seen sediment accumulation, and beaver dam failure.  My guess in lower gradient braided systems with ample rain and rapid vegetation response from beaver eating of riparian vegetation, beavers may be beneficial if sediment reduction is critical.  However, they can also stop up culverts or do other damage if they locate in a the wrong places.  Treatments need to fit the circumstances, and you have the right idea in looking for ways to prioritize your effort or advice.

Predicting rain and runoff, flooding is largely based on limited records, and in many instances you are not going everything you want.  Models will typically use all the data you can muster, and be wanting for more.  You need a combination of recording rain guage stations preferred and recording stream gauges and have an absolute minimum of 10 years record for any predictive capability or comparisons with the old data stations, however even 100 years is probably not enough for some things.  Consider the rainfall event we had in October near Charleston, SC.  Using the available data, we had the 1000 year event on the national forest, but as soon as we insert this data into the total and recalibrate, perhaps it may be the 500 year event.  Weather specialists do a reasonable good job now with their data and tools for predicting weather within the next few days, weeks or maybe as far as months, that is pushing it.  However, the predictive tools rely on spatial data, and a lot of it.  In areas with a lot of topographical relief, adding more rainguages can help coverage of individual storms or help locate areas that then to get more rain, but they are not necessarily going to improve prediction but may help with years of data.  Weather patterns shift, the jet stream shifts, you can have wet years, dry years, and individual event severity is dependent on a lot more than a truck load of data.  It is best to model and predict as best as we can, but identify the uncertainty and build infrastructure, homes, etc. accordingly.  If you are in the floodplain, elevate your structure above the 100 year or more elevation, and such as put your garage on the lower level and accept your car may or may not be flooded in your lifetime.  Most people don't have the information at all so that they can consider it as an option. 

You should use whatever you can find and have time to interpret.  A local archeologist, geologist, and land surveyor used to interpreting the records may help.  Aerial photos always good, but how much time to you have?  If you can ascertain the types of land use changes and identify any really major ones like land clearing, farming, overgrazing, mining especially hydraulic mining, hydrologic modifications like ditching, old landslides, geology maps of faults, strikes, dips, and other lithological features all add to your end product.  But in most instances, time is not your friend.  Maybe some old timers or former landowners have info too, pictures, etc.  Even surveys by early explorers may sometimes have touched your area of interest.  And the old boundary surveys and in some instances the SCS early soil maps can show streams and other interesting things.  If you are familiar with the US Forest Service, they have publications on watershed and hydrologic assessments you might find useful on the internet.  But the type and level of detail may also depend on your ultimate purpose.  I used to work on the Siskiyou National Forest years ago, and the land records were all microfiche, and time consuming to read.  Although interesting to read, we seldom had time to consider that detail.  However archeologists and historians of today have many tools including GIS and digital filing to store data that we did not have 40 years ago.  Since you mentioned vegetation associations, so there may be botanical records available from botanists or ecologists.  Sometimes ecologists do surveys of the soils and landtypes, burning, vegetation, etc. and come up with their best guess (they don't call it that, probably something like ecological land classification) of what it once was. 

Unless the dams are pretty big, you need LiDAR.  We have found old dikes in the coastal plain, beaver dams sometimes from LiDAR coverage.  I doubt if satellite imagery is suitable except for the larger dams, which I would not call check dams.  A generality relative to checkdams, the higher the check dam, the more hydrologically unstable it is.  Better to have more frequent low rise check dams for erosion control that the high check dams that are so hydrologically unstable.  You may want a loose rock checkdam for a grade control to stop gullying, but keep them low and make sure the thalweg is low enough or the edges high enough, so that the high flows don't erode around the dam.  In sandy terrain, a 1 foot drop can erode 6 feet deep if the plunge is not rocked and abrupt.  A deep plunge will often lead to failure.  I am unsure that satellite imagery is detailed enough to locate existing ones, but maybe if you don't have a lot of trees or vegetation to hide them like we do. 

In my opinion, once identified properly the beneficiaries, ask the population what are they are prepared to do and how much are they ready to pay to achieve a sustainable system in which water reuse is affordable to farmers. Ask the farmers what are their priorities and limitations and why do they need more water and what product are they planned to cultivate before planning an irrigation system. Ask the politicians what are they really want to do to support the new project. And finally, ask the technicians if the solution is reasonable.

Best regards

Please take a look at the follwing publication: "A Handbook for

Integrated Water Resources Management in Basins" GWP, 2009

Integrated Water Resources Management (IWRM) is the process of supporting the synchronized development and management of water, land and related natural resources, in order to maximize the resultant economic and social welfare in an equitable manner without compromising the sustainability of the vital ecosystem. IWRM is increasingly gaining importance as the approach to water resources management has shifted from supply driven to demand driven. The concept of IWRM is also influenced by the increasing water scarcity and deterioration of water quality. The world is going through tremendous changes in climate, land use, increase in population, industrialization, etc. This has put a lot of pressure on the availability of water to meet the increasing demands for various purposes. The sustainable management of water can be ensured only through integrated approach with cooperation of various departments and stakeholders. Availability of clean and safe water is a major challenge in many of the Nations. Unsound management of water weakens the development of mankind and adds to the imbalanced distribution of economic welfare. Pollution, depletion of water resources and collapse of ecological functions are of universal, regional and local concern.

The concept of IWRM has gained wide acceptance as a guiding principle in the water sector. The aim is to promote economic and social development by addressing and balancing diverse interests of water users, while simultaneously safeguarding water resources. This is the rationale for the IWRM approach that has now been accepted internationally as the way forward for efficient, equitable and sustainable development and management of the world's limited water resources and for coping with conflicting demands.

Using ncdump tool would be the most appropriate, as it's made directly by Unidata - the NetCDF format developer. It can eventually dump the data from NetCDF to e.g. txt format, extract file header and so on. Check https://www.unidata.ucar.edu/software/netcdf/docs/netcdf/ncdump.html

If you need to extract the data for your specific area of interest from the global grid file, then try ncks tool http://linux.die.net/man/1/ncks

Both mentioned works for Windows and Unix environment. 

Good luck!

Thank you Dear Hein & Dear Janaka

Regards

You can use  QGIS software in which have a complement named TauDEM deloloped in Utah State University specifically for hydrology and watershed delineation

Thank you Sir. Abdelazim M Negm. I will look for some documents concerning with this information

Dear Vinayak, Dr. Chandra Prasad Ghimire defended very good thesis on this topic: Hydrological impacts of reforesting degraded pasture land in the Middle Mountain Zone pof Central Nepal at the Vrije Universiteit Amsterdam in spring last year. May be this can help you. Best regards       Jan

Dear Dr-Radwan A Al-Weshah

Thank you very much for your attention and cooperation.

All above discussion is useful. To make things easy, divide your watershed into small subbasins to be able to use the Rational Formula. Route the triangular  flood hydrograph from one outlet to another outlet downstream (e.g., using Muskingum method). The resulting hydrograph shall be trapezoidal shape. Give the time base and shape of hydrograph you can calculate the volume.

Remember to include any other  abstractions if your storm duration is long (greater than 24 hrs)

Hi Frank

I often wondered about micro- and meso-climatic effects of the purposive lowering of the groundwater table over large farm areas in the Netherlands (especially in spring) as well as converting the Zuiderzee (open to the Atlantic) into the IJsselmeer lake fed by the river Rhine system. Both in the past century. Your best chance to get some data would seem from grassland research in "Wageningen" as the groundwater lowering is aimed at earlier grass growth in spring.

May you find this topics interesting!

I agree with colleague Sajid recommendation of using GRASS  GIS  and/or, spatial analysis of GIS, and/or  global Mapper for this task  as you will not be only capable of  delineating watershed boundaries of the basin but you will also be able to calculate and analyze the other watershed and drainage parameters.

Great!Great....

You can also check the attached materials for further reading.

Dear Wilbert,

In my opinion, the most important perception is about pollution of  sources.

In the contexto of "planning", please see:

Nine Minimum Elements to Be Included in a Watershed Plan

Regards,

Vanessa

The question is a good one and as a chemist I am not happy with any of the responses so far.  Most research relies on measuring molybdate reactive P before/after treatment of soil solutions/ runoff/ flow-through to discriminate between organic and inorganic forms of P in solution. Unless the species are first separated molybdate reactivity is an indiscriminate tool.  And separation itself is complex because much of the P, even if present as phosphate, may in fact be part of suspended colloids. I'm sorry to say that separation followed by measurement is the way to go, but I'm unaware of any authoritative research on the topic, i.e. selective measurement is probably a project in itself. Were I to go there I would use  chromatographic separation with  dual post column detection, e.g. using ICP on one leg and molybdate on the other.  On the ICP leg I would simultaneously measure Fe, Al and C for starters as indices of the forms in which the P may be present.  Good luck!!

I think these are useful for you ....

Dear Farzad,

You need to have full permission on your project folder. Be sure that all your layers has the same geographic projection and that they cover your full area. You also need to change the regional setting in your computer to USA,  I hope this helps.

I just try to check with zeolites Molecular Sieve beds and so on, but tritium always permeates even rafm steel...

Hi freind Intigrated development process in watershed means that the enhancement in soil moisture, crop yield, water table greenery, plantation, income of farm family and happiness sows the positive impact of soil and water conservation activities in the watershed. Thanks

My Dear following articles May be useful to you. Thanks

Dear Muhammad,

In our article "Climate projections for ecologists" we have a section that describes the 3 more commonly used techniques to down-scale a Global Climate Model (GCM). Table 2 (Advantages and Disadvantages of Different Techniques for Rationalizing Global Climate Model Output)  in our article briefly describes these techniques, and statistical down-scaling is one of them.

A key question you may ask when choosing down-scaling techniques is if you need to gain pixel resolution (so the map will 'look' better and match other spatial data you already have), or if in addition of adding the pixels resolution you need climate information (a better climatic presentation at a smaller scale). To give you a quick example, you may have an output from a GCM at 100km pixel, and you may use  stats to get a 100m pixel, but you won't be adding any climatic information to it.  Then, if you needed detailed climatic information the statistical downscaling may not be appropriate method, if you had access to a dynamically down-scaled model, then,that would be the best choice.

The paper I mentioned earlier also present a table with links to all public repositories: Table 3. Overview of Climate Projections Available for Use in Ecological Studies, Based on Different Regionalizing Techniques. You may find this information useful perhaps.

Regards,

Luciana 

Check out the following DSS: Mike Basin, WEAP, (Water Situation Assessment Model) WSAM, RIBASIM, Eelbe-DSS!